Alteración de la microbiota intestinal y su relación con enfermedades gastrointestinales y hepatobiliares / Disruption of the intestinal microbiota and its relationship with gastrointestinal and hepatobiliary diseases

La interrupción de la simbiosis que existe entre el cuerpo humano y su microbioma puede resultar en una disbiosis, un desequilibrio en la interacción huésped-microbiota, que puede asociarse al desarrollo de diversas enfermedades como el síndrome de intestino irritable, hígado graso no alco-hólico, enfermedad hepática alcohólica y cirrosis, entre otras. En ciertas condiciones patológicas y por múltiples factores de riesgo, la capacidad de autorregulación del intestino se puede alterar, contribuyendo al incremento de la permeabilidad con inflamación intestinal crónica. El diagnóstico y el tratamiento, así como la relación entre la permeabilidad intestinal, la disbiosis y las patologías gastrointestinales y hepatobiliares, todavía no tienen estudios clínicos validados o con el soporte científico adecuado, por lo que se realiza una revisión de la literatura con la finalidad de aportar conceptos que puedan orientar con respecto a la importancia del estudio del microbioma humano en estas enfermedades.

Disruption of the symbiosis that exists between the human body and its microbiome can result in dys-biosis, an imbalance in the host-microbiota interaction, which may be associated with the develop-ment of various diseases such as irritable bowel syndrome, non-alcoholic fatty liver disease, alcoholic liver disease and cirrhosis, among others. In certain pathological conditions and due to multiple risk factors, the self-regulating capacity of the intestine may be lost, contributing to increased permeability with chronic intestinal inflammation. Its diagnosis and treatment as well as the relationship between intestinal permeability, dysbiosis and gastrointestinal and hepatobiliary pathologies have not been validated in clinical studies or have adequate scientific support, so a review of the literature is carried out in order to provide concepts that can guide with respect to the importance of the study of the human microbiome in these diseases

Metagenomics approach to identify lignocellulose-degrading enzymes in the gut microbiota of the Chinese bamboo rat cecum

BACKGROUND: Lignocellulose is considered a renewable organic material, but the industrial production of biofuel from lignocellulose is challenging because of the lack of highly active hydrolytic enzymes. The guts of herbivores contain many symbiotic microorganisms that have evolved to hydrolyze plant lignocellulose. Chinese bamboo rats mainly consume high-fiber foods, indicating that some members of the intestinal tract microbiota digest lignocellulose, providing these rats with the energy required for growth. RESULTS: Here, we used metagenomics to analyze the diversity and functions of the gut microbiota in Chinese bamboo rats. We identified abundant populations of lignocellulose-degrading bacteria, whose main functions involved carbohydrate, amino acid, and nucleic acid metabolism. We also found 587 carbohydrate-active enzyme genes belonging to different families, including 7 carbohydrate esterase families and 21 glycoside hydrolase families. The glycoside hydrolase 3, glycoside hydrolase 1, glycoside hydrolase 43, carbohydrate esterase 4, carbohydrate esterase 1, and carbohydrate esterase 3 families demonstrated outstanding performance. CONCLUSIONS: The microbes and enzymes identified in our study expand the existing arsenal of proficient degraders and enzymes for lignocellulosic biofuel production. This study also describes a powerful approach for targeting gut microbes and enzymes in numerous industries.

Repeated mild traumatic brain injury affects microbial diversity in rat jejunum

Traumatic brain injuries (TBI) manifest into post-traumatic stress disorders such as anxiety comorbid with gut ailments. Theperturbations in gut microbial communities are often linked to intestinal and neuropsychological disorders. We havepreviously reported anxiety and abnormalities in gut function in mild TBI (MTBI)-exposed rats. The current studydemonstrates the changes in gut microbiome of MTBI-exposed animals and discusses its implications in intestinal healthand behaviours. The rats were subjected to repeated MTBI (rMTBI) and microbial composition in jejunum was examinedafter 6 h, 48 h and 30 days of rMTBI. Significant reduction in bacterial diversity was observed in the rMTBI-exposedanimals at all the time points. Principal coordinate analysis based on weighted UniFrac distances indicated substantialdifferences in gut microbial diversity and abundances in rMTBI-exposed animals as compared to that in healthy controls.The abundance of Proteobacteria increased dramatically with reciprocal decrease in Firmicutes after rMTBI. At the genuslevel, Helicobacter, Lactobacillus, Campylobacter, and Streptococcus were found to be differentially abundant in thejejunum of rMTBI-exposed rats as compared to sham controls indicating profound dysbiosis from the healthy state.Furthermore, substantial depletion in butyrate-producing bacterial communities was observed in rMTBI-exposed animals.These results suggest that the traumatic stress alters the gut microbiome with possible implications in gut health andneuropsychopathology.

Bacterial community structure in soils contaminated with electronic waste pollutants from Delhi NCR, India

Background: Microbial community analysis of electronic waste (e-waste)-polluted environments is of interest to understand the effect of toxic e-waste pollutants on the soil microbial community and to evaluate novel microorganisms resisting the toxic environment. The present study aims to investigate the bacterial community structure in soils contaminated with e-waste from various sites of Loni and Mandoli (National Capital Region (NCR), India) where e-waste dumping and recycling activities are being carried out for many years. Results: Interferences to soil metagenomic DNA extraction and PCR amplification were observed because of the presence of inhibiting components derived from circuit boards. Whole-metagenome sequencing on the Illumina MiSeq platform showed that the most abundant phyla were Proteobacteria and Firmicutes. Deltaproteobacteria and Betaproteobacteria were the most common classes under Proteobacteria. Denaturing gradient gel electrophoresis (DGGE) analysis of the bacterial 16S rRNA gene showed that e-waste contamination altered the soil bacterial composition and diversity. There was a decrease in the number of predominant bacterial groups like Proteobacteria and Firmicutes but emergence of Actinobacteria in the contaminated soil samples. Conclusions: This is the first report describing the bacterial community structure of composite soil samples of ewaste-contaminated sites of Loni and Mandoli, Delhi NCR, India. The findings indicate that novel bacteria with potential bioremediating properties may be present in the e-waste-contaminated sites and hence need to be evaluated further.

Composition of bacterial community in enrichment cultures of shale by-products from Irati Formation, Brazil

ABSTRACT We examined microbial communities from enriched fine and retorted shale particles using sequencing of V4 variable region of 16S rRNA. High number of microbial genera was found in both enriched shale by-products that were dominate by Actinobacteria, Firmicutes and Proteobacteria, showing differences due to microbial colonization after the pyrolysis process.

Early bacterial biofilm colonizers in the coastal waters of Mauritius

Background: The past years have witnessed a growing number of researches in biofilm forming communities due to their environmental and maritime industrial implications. To gain a better understanding of the early bacterial biofilm community, microfiber nets were used as artificial substrates and incubated for a period of 24 h in Mauritian coastal waters. Next-generation sequencing technologies were employed as a tool for identification of early bacterial communities. Different genes associated with quorum sensing and cell motility were further investigated. Results: Proteobacteria were identified as the predominant bacterial microorganisms in the biofilm within the 24 h incubation, of which members affiliated to Gammaproteobacteria, Alphaproteobacteria and Betaproteobacteria were among the most abundant classes. The biofilm community patterns were also driven by phyla such as Firmicutes, Bacteroidetes, Chloroflexi, Actinobacteria and Verrucomicrobia. The functional analysis based on KEGG classification indicated high activities in carbohydrate, lipid and amino acids metabolism. Different genes encoding for luxI, lasI, agrC, flhA, cheA and cheB showed the involvement of microbial members in quorum sensing and cell motility. Conclusion: This study provides both an insight on the early bacterial biofilm forming community and the genes involved in quorum sensing and bacterial cell motility.

Bioleaching of nickel from spent petroleum catalyst using Acidithiobacillus thiooxidans DSM-11478.

The present work deals with optimization of culture conditions and process parameters for bioleaching of spent petroleum catalyst collected from a petroleum refinery. The efficacy of Ni bioleaching from spent petroleum catalyst was determined using pure culture of Acidithiobacillus thiooxidans DSM-11478. The culture conditions of pH, temperature and headspace volume to media volume ratio were optimized. EDX analysis was done to confirm the presence of Ni in the spent catalyst after roasting it to decoke its surface. The optimum temperature for A. thiooxidans DSM-11478 growth was found to be 32 °C. The enhanced recovery of nickel at very low pH was attributed to the higher acidic strength of sulfuric acid produced in the culture medium by the bacterium. During the bioleaching process, 89% of the Ni present in the catalyst waste could be successfully recovered in optimized conditions. This environment friendly bioleaching process proved efficient than the chemical method. Taking leads from the lab scale results, bioleaching in larger volumes (1, 5 and 10 L) was also performed to provide guidelines for taking up this technology for in situ industrial waste management.

Taxonomy of the Rhizobia: Current Perspectives.

The classification of rhizobia has been gone through a substantial change in recent years due to the addition of several new genera and species to this important bacterial group. Recent studies have shown the existence of a great diversity among nitrogen-fixing bacteria isolated from different legumes. Currently, more than 98 species belonging to 14 genera of α- and β- proteobacteria have been described as rhizobia. The genera Rhizobium, Mezorhizobium, Ensifer (formerly Sinorhizobium), Bradyrhizobium, Phyllobacterium, Microvirga, Azorhizobium, Ocrhobactrum, Methylobacterium, Devosia, Shinella (Class of α- proteobacteria), Burkholderia, Cupriavidus (formerly Ralstonia) (Class of β-proteobacteria) and some γ-proteobacteria, form the set of the bacteria known as legume’s symbionts. There is certainly much to discover, since only 23% of known legumes were identified specifically for symbiotic relationship up to date. The discovery of new symbionts associated with legumes is necessary to gain deep insight into the taxonomy of the rhizobia. A literature review of the currently recognized classification of rhizobia is presented in this paper.

Does Wolbachia infection affect Trichogramma atopovirilia behaviour? / A infecção por Wolbachia afeta o comportamento de Trichogramma atopovirilia?

Unisexual Trichogramma forms have attracted much attention due to their potential advantages as biocontrol agents. Fitness studies have been performed and understanding the cost that Wolbachia may inflict on their hosts will help in deciding if Wolbachia infected (unisexual) forms are indeed better than sexual forms when used in biological control programmes. The influence of Wolbachia on the foraging behaviour (including walking activity and speed) of T. atopovirilia is reported in this paper. Temperature strongly affected T. atopovirilia female walking activity, but Wolbachia infected and uninfected females differed in none of the behavioural components that were measured such as walking activity and walking speed. Walking activity was highest at 25 ºC and differed significantly from that at 20 and 15 ºC. Trichogramma wasps were highly affected at 15 ºC. Behaviour analysis with females showed that female wasps spend most of the time on drilling + ovipositing on host eggs followed by host drumming and walking while drumming. The parasitism rate and number of offspring did not differ significantly between infected and cured Trichogramma females. Biological control implications of these findings are discussed.

Formas unissexuais de Trichogramma têm despertado a atenção de pesquisadores devido as potenciais vantagens deste parasitóide como agente de controle biológico. O estudo do "Fitness" tem sido avaliado e entender o custo de ser infectado por Wolbachia ajudará em determinar se formas infectadas por Wolbachia (unisexuais) são realmente melhores que as sexuadas quando utilizadas em programas de controle biológico. A influência de Wolbachia no comportamento de procura (incluindo a atividade e a velocidade de caminhamento) de T. atopovirilia é relatada neste artigo. A temperatura afetou grandemente a atividade de caminhamento de fêmeas de T. atopovirilia, entretanto os componentes de comportamento tais como a atividade e a velocidade de caminhamento não diferiram em relação às fêmeas infectadas e não infectadas. A atividade de caminhamento foi maior a 25 ºC e diferiu significativamente de 20 e 15 ºC. Fêmeas de Trichogramma foram altamente afetados a 15 ºC. Em função da análise do comportamento com fêmeas, pode-se verificar que houve maior tempo gasto no processo de oviposição, seguido pelo toque com as antenas sobre os ovos dos hospedeiros e do caminhamento ao mesmo tempo que toca os ovos com as antenas. A taxa de parasitismo e o número de descendentes não diferiram significativamente entre fêmeas de Trichogramma infectadas e curadas da infecção por Wolbachia. As implicações dos resultados obtidos sobre o controle biológico são discutidas.

Bioinformatics Analysis of Hsp20 Sequences in Proteobacteria

Heat shock proteins are a class of molecular chaperones that can be found in nearly all organisms from Bacteria, Archaea and Eukarya domains. Heat shock proteins experience increased transcription during periods of heat induced osmotic stress and are involved in protein disaggregation and refolding as part of a cell's danger signaling cascade. Heat shock protein, Hsp20 is a small molecular chaperone that is approximately 20kDa in weight and is hypothesized to prevent aggregation and denaturation. Hsp20 can be found in several strains of Proteobacteria, which comprises the largest phyla of the Bacteria domain and also contains several medically significant bacterial strains. Genomic analyses were performed to determine a common evolutionary pattern among Hsp20 sequences in Proteobacteria. It was found that Hsp20 shared a common ancestor within and among the five subclasses of Proteobacteria.This is readily apparent from the amount of sequence similarities within and between Hsp20 protein sequences as well as phylogenetic analysis of sequences from proteobacterial and non-proteobacterial species.