Demonstration of IS711 transposition in Brucella ovis and Brucella pinnipedialis

<p>Abstract</p> <p>Background</p> <p>The <it>Brucella </it>genome contains an insertion sequence (IS) element called IS<it>711 </it>or IS<it>6501</it>, which is specific to the genus. The copy number of IS<it>711 </it>varies in the genome of the different <it>Brucella </it>species, ranging from 7 in <it>B. abortus</it>, <it>B. melitensis </it>and <it>B. suis </it>to more than 30 in <it>B. ovis </it>and in <it>Brucella </it>strains isolated from marine mammals. At present, there is no experimental evidence of transposition of IS<it>711</it>, but the occurrence of this element with a high copy number in some species, and the isolation of <it>Brucella </it>strains with "ectopic" copies of IS<it>711 </it>suggested that this IS could still transpose.</p> <p>Results</p> <p>In this study we obtained evidence of transposition of IS<it>711 </it>from the <it>B. ovis </it>and <it>B. pinnipedialis </it>chromosomes by using the "transposon trap" plasmid pGBG1. This plasmid expresses resistance to tetracycline only if the repressor gene that it contains is inactivated. The strains <it>B. melitensis </it>16 M, <it>B. abortus </it>RB51, <it>B. ovis </it>BOC22 (field strain) and <it>B. pinnipedialis </it>B2/94, all containing the plasmid pGBG1, were grown in culture media with tetracycline until the appearance of tetracycline resistant mutants (Tc^R). Tc^Rmutants due to IS<it>711 </it>transposition were only detected in <it>B. ovis </it>and <it>B. pinnipedialis </it>strains.</p> <p>Conclusion</p> <p>Four different copies of IS<it>711 </it>were found to transpose to the same target sequence in the plasmid pGBG1. This demonstrated that IS<it>711 </it>are active <it>in vivo</it>, specially in <it>Brucella </it>species with a high number of IS<it>711 </it>copies as <it>B. ovis </it>and <it>B. pinnipedialis</it>.</p

Brucella abortus ure2 region contains an acid-activated urea transporter and a nickel transport system

<p>Abstract</p> <p>Background</p> <p>Urease is a virulence factor that plays a role in the resistance of <it>Brucella </it>to low pH conditions, both <it>in vivo </it>and <it>in vitro</it>. <it>Brucella </it>contains two separate urease gene clusters, <it>ure1 </it>and <it>ure2</it>. Although only <it>ure1 </it>codes for an active urease, <it>ure2 </it>is also transcribed, but its contribution to <it>Brucella </it>biology is unknown.</p> <p>Results</p> <p>Re-examination of the <it>ure2 </it>locus showed that the operon includes five genes downstream of <it>ureABCEFGDT </it>that are orthologs to a <it>nikKMLQO </it>cluster encoding an ECF-type transport system for nickel. <it>ureT </it>and <it>nikO </it>mutants were constructed and analyzed for urease activity and acid resistance. A non-polar <it>ureT </it>mutant was unaffected in urease activity at neutral pH but showed a significantly decreased activity at acidic pH. It also showed a decreased survival rate to pH 2 at low concentration of urea when compared to the wild type. The <it>nikO </it>mutant had decreased urease activity and acid resistance at all urea concentrations tested, and this phenotype could be reverted by the addition of nickel to the growth medium.</p> <p>Conclusions</p> <p>Based on these results, we concluded that the operon <it>ure2 </it>codes for an acid-activated urea transporter and a nickel transporter necessary for the maximal activity of the urease whose structural subunits are encoded exclusively by the genes in the <it>ure1 </it>operon.</p

Chemical Characterization of Asturian Cider

Ninety-four samples of Asturian natural cider were analyzed for titratable and volatile acidities, pH, alcoholic, total polyphenol, and acidic polysaccharide contents, nonvolatile acids, polyalcohols, residual sugars, and major volatile compounds. A partial least-squares regression analysis (PLR-1) was performed to correlate the chemical composition and the origin of the raw material, the cider samples being grouped into two categories: an “odd” class, cider made from foreign apples (1995 and 1997), and an “even” class, ciders made from Asturian apples (1996 and 1998). The mathematical model has a multiple linear correlation coefficient of 80%

Transcriptome Analysis of the Brucella abortus BvrR/BvrS Two-Component Regulatory System

International audienceBackgroundThe two-component BvrR/BvrS system is essential for Brucella abortus virulence. It was shown previously that its dysfunction alters the expression of some major outer membrane proteins and the pattern of lipid A acylation. To determine the genes regulated by BvrR/BvrS, we performed a whole-genome microarray analysis using B. abortus RNA obtained from wild type and bvrR mutant cells grown in the same conditions.Methodology/Principal FindingsA total of 127 differentially expressed genes were found: 83 were over expressed and 44 were less expressed in the bvrR mutant. Two operons, the phosphotransferase system and the maltose transport system, were down-regulated. Several genes involved in cell envelope or outer membrane biogenesis were differentially expressed: genes for outer membrane proteins (omp25a, omp25d), lipoproteins, LPS and fatty acid biosynthesis, stress response proteins, chaperones, flagellar genes, and twelve genes encoding ABC transport systems. Ten genes related with carbon metabolism (pckA and fumB among others) were up-regulated in the bvrR mutant, and denitrification genes (nirK, norC and nosZ) were also regulated. Notably, seven transcriptional regulators were affected, including VjbR, ExoR and OmpR that were less expressed in the bvrR mutant. Finally, the expression of eleven genes which have been previously related with Brucella virulence was also altered.Conclusions/SignificanceAll these data corroborate the impact of BvrR/BvrS on cell envelope modulation, confirm that this system controls the carbon and nitrogen metabolism, and suggest a cross-talk among some regulators to adjust the Brucella physiology to the shift expected to occur during the transit from the extracellular to the intracellular niche

Antibióticos en periodoncia

Como la enfermedad periodontal es basicamente una enfermedad infecciosa, el uso de antibióticos parece justificado. En los últimas años, numerosos ensayos clínicos han demostrado el valor de la antibioticoterapia en el tratamiento de las enfermedades periodontales, aunque siempre como un complemento más que una alternativa al tratamiento periodontal instrumental

Antibióticos en periodoncia

Como la enfermedad periodontal es basicamente una enfermedad infecciosa, el uso de antibióticos parece justificado. En los últimas años, numerosos ensayos clínicos han demostrado el valor de la antibioticoterapia en el tratamiento de las enfermedades periodontales, aunque siempre como un complemento más que una alternativa al tratamiento periodontal instrumental

An international effort towards developing standards for best practices in analysis, interpretation and reporting of clinical genome sequencing results in the CLARITY Challenge

This is an Open Access article distributed under the terms of the Creative Commons Attribution License.-- et al.[Background]: There is tremendous potential for genome sequencing to improve clinical diagnosis and care once it becomes routinely accessible, but this will require formalizing research methods into clinical best practices in the areas of sequence data generation, analysis, interpretation and reporting. The CLARITY Challenge was designed to spur convergence in methods for diagnosing genetic disease starting from clinical case history and genome sequencing data. DNA samples were obtained from three families with heritable genetic disorders and genomic sequence data were donated by sequencing platform vendors. The challenge was to analyze and interpret these data with the goals of identifying disease-causing variants and reporting the findings in a clinically useful format. Participating contestant groups were solicited broadly, and an independent panel of judges evaluated their performance. [Results]: A total of 30 international groups were engaged. The entries reveal a general convergence of practices on most elements of the analysis and interpretation process. However, even given this commonality of approach, only two groups identified the consensus candidate variants in all disease cases, demonstrating a need for consistent fine-tuning of the generally accepted methods. There was greater diversity of the final clinical report content and in the patient consenting process, demonstrating that these areas require additional exploration and standardization. [Conclusions]: The CLARITY Challenge provides a comprehensive assessment of current practices for using genome sequencing to diagnose and report genetic diseases. There is remarkable convergence in bioinformatic techniques, but medical interpretation and reporting are areas that require further development by many groups.This work was supported by funds provided through the Gene Partnership and the Manton Center for Orphan Disease Research at Boston Children’s Hospital and the Center for Biomedical Informatics at Harvard Medical School and by generous donations in-kind of genomic sequencing services by Life Technologies (Carlsbad, CA, USA) and Complete Genomics (Mountain View, CA, USA).Peer Reviewe

Effectiveness of the Natura 2000 network in protecting Iberian endemic fauna

The Iberian Peninsula is a major European region of biodiversity, as it harbours more than 30% of European endemic species. Despite a number of studies having evaluated the ability of nature reserves to protect certain taxa, there is still a lack of knowledge on how Iberian endemic fauna are represented in these reserves. We detected biodiversity hotspots of Iberian endemicity and evaluated the effectiveness of the Natura 2000 network (N2000) in representing 249 endemic species from eight animal taxonomic groups (amphibians, mammals, freshwater fishes, reptiles, water beetles, butterflies, lacewings and dung beetles). We found that only the 10% of these Iberian endemic species are considered species of community interest (i.e. species included in the Annexes of the Habitats Directive). We conducted gap analyses and null models of representativeness in N2000. Generally, N2000 is effective in its representation of Iberian endemic fauna, although we detected species and few hotspots of endemism that were still not represented. It is necessary to declare a few new protected areas, thus enhancing N2000's effectiveness in the conservation of the Iberian endemic fauna. Although the aim of N2000 is to protect species listed in the Birds and Habitats Directives, the conservation status of endemic species from one of the most important areas of Europe in terms of biodiversity, could be also a concern for the European Union. Our results are useful in the context of the recent European Commission mandate calling for a ‘fitness check’ of the Birds and Habitats Directives. This approach could be also applicable to other regions with high value of endemicity.DS‐F was supported by a post‐doctoral contract funded by Universidad de Castilla‐La Mancha and the European Social Fund (ESF). PA was supported by a ‘Ramón y Cajal’ contract (RYC‐2011‐07670, MINECO). This research was partially funded by project POII11‐0277‐5747 (Junta de Castilla‐La Mancha).Peer Reviewe

Impact of global PTP1B deficiency on the gut barrier permeability during NASH in mice.

OBJECTIVE:Non-alcoholic steatohepatitis (NASH) is characterized by a robust pro-inflammatory component at both hepatic and systemic levels together with a disease-specific gut microbiome signature. Protein tyrosine phosphatase 1 B (PTP1B) plays distinct roles in non-immune and immune cells, in the latter inhibiting pro-inflammatory signaling cascades. In this study, we have explored the role of PTP1B in the composition of gut microbiota and gut barrier dynamics in methionine and choline-deficient (MCD) diet-induced NASH in mice. METHODS:Gut features and barrier permeability were characterized in wild-type (PTP1B WT) and PTP1B-deficient knockout (PTP1B KO) mice fed a chow or methionine/choline-deficient (MCD) diet for 4 weeks. The impact of inflammation was studied in intestinal epithelial and enteroendocrine cells. The secretion of GLP-1 was evaluated in primary colonic cultures and plasma of mice. RESULTS:We found that a shift in the gut microbiota shape, disruption of gut barrier function, higher levels of serum bile acids, and decreased circulating glucagon-like peptide (GLP)-1 are features during NASH. Surprisingly, despite the pro-inflammatory phenotype of global PTP1B-deficient mice, they were partly protected against the alterations in gut microbiota composition during NASH and presented better gut barrier integrity and less permeability under this pathological condition. These effects concurred with higher colonic mucosal inflammation, decreased serum bile acids, and protection against the decrease in circulating GLP-1 levels during NASH compared with their WT counterparts together with increased expression of GLP-2-sensitive genes in the gut. At the molecular level, stimulation of enteroendocrine STC-1 cells with a pro-inflammatory conditioned medium (CM) from lipopolysaccharide (LPS)-stimulated macrophages triggered pro-inflammatory signaling cascades that were further exacerbated by a PTP1B inhibitor. Likewise, the pro-inflammatory CM induced GLP-1 secretion in primary colonic cultures, an effect augmented by PTP1B inhibition. CONCLUSION:Altogether our results have unraveled a potential role of PTP1B in the gut-liver axis during NASH, likely mediated by increased sensitivity to GLPs, with potential therapeutic value