83 research outputs found

    Early results of treatment for congenital clubfoot using the Ponseti method

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    The purpose of this study was to evaluate the early results of the Ponseti method in reducing extensive corrective surgery rates for congenital idiopathic clubfoot in patients treated in Children’s Orthopaedic Clinic and Rehabilitation Department Medical University of Lublin between the years 2007–2011. Thirty-five patients with 47 idiopathic clubfeet were followed prospectively while being managed with the Ponseti method. Clubfoot severity was graded with use of the Dimeglio system. The initial correction was achieved, and early results were measured by using Pirani scoring method

    What traits are carried on mobile genetic elements, and why?

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    Although similar to any other organism, prokaryotes can transfer genes vertically from mother cell to daughter cell, they can also exchange certain genes horizontally. Genes can move within and between genomes at fast rates because of mobile genetic elements (MGEs). Although mobile elements are fundamentally self-interested entities, and thus replicate for their own gain, they frequently carry genes beneficial for their hosts and/or the neighbours of their hosts. Many genes that are carried by mobile elements code for traits that are expressed outside of the cell. Such traits are involved in bacterial sociality, such as the production of public goods, which benefit a cell's neighbours, or the production of bacteriocins, which harm a cell's neighbours. In this study we review the patterns that are emerging in the types of genes carried by mobile elements, and discuss the evolutionary and ecological conditions under which mobile elements evolve to carry their peculiar mix of parasitic, beneficial and cooperative genes

    Local Gene Silencing of Monocyte Chemoattractant Protein-1 Prevents Vulnerable Plaque Disruption in Apolipoprotein E-Knockout Mice

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    Monocyte chemoattractant protein-1 (MCP-1), a CC chemokine (CCL2), has been demonstrated to play important roles in atherosclerosis and becoming an important therapeutic target for atherosclerosis. The present study was undertaken to test the hypothesis that local RNAi of MCP-1 by site-specific delivery of adenovirus-mediated small hairpin RNA (shRNA) may enhance plaque stability and prevent plaque disruption in ApoE−/− mice. We designed an adenovirus-mediated shRNA against mouse MCP-1 (rAd5-MCP-1-shRNA). Male apolipoprotein E-knockout (ApoE−/−) mice (n = 120) were fed a high-fat diet and vulnerable plaques were induced by perivascular placement of constrictive collars around the carotid artery, intraperitoneal injection of lipopolysaccharide and stress stimulation. Mice were randomly divided into RNA interference (Ad-MCP-1i) group receiving local treatment of rAd5-MCP-1-shRNA suspension, Ad-EGFP group receiving treatment of rAd5-mediated negative shRNA and mock group receiving treatment of saline. Two weeks after treatment, plaque disruption rates were significantly lower in the Ad-MCP-1i group than in the Ad-EGFP group (13.3% vs. 60.0%, P = 0.01), and local MCP-1 expression was significantly inhibited in the Ad-MCP-1i group confirmed by immunostaining, qRT-PCR and western blot (P<0.001). Compared with the Ad-EGFP group, carotid plaques in the Ad-MCP-1i group showed increased levels of collagen and smooth muscle cells, and decreased levels of lipid and macrophages. The expression of inflammatory cytokines and activities of matrix metalloproteinases (MMPs) were lower in the Ad-MCP-1i group than in the Ad-EGFP group. In conclusion, site-specific delivery of adenoviral-mediated shRNA targeting mouse MCP-1 downregulated MCP-1 expression, turned a vulnerable plaque into a more stable plaque phenotype and prevented plaque disruption. A marked suppression of the local inflammatory cytokine expression may be the central mechanism involved

    Multi-host environments select for host-generalist conjugative plasmids

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    BACKGROUND: Conjugative plasmids play an important role in bacterial evolution by transferring ecologically important genes within and between species. A key limit on interspecific horizontal gene transfer is plasmid host range. Here, we experimentally test the effect of single and multi-host environments on the host-range evolution of a large conjugative mercury resistance plasmid, pQBR57. Specifically, pQBR57 was conjugated between strains of a single host species, either P. fluorescens or P. putida, or alternating between P. fluorescens and P. putida. Crucially, the bacterial hosts were not permitted to evolve allowing us to observe plasmid evolutionary responses in isolation. RESULTS: In all treatments plasmids evolved higher conjugation rates over time. Plasmids evolved in single-host environments adapted to their host bacterial species becoming less costly, but in the case of P. fluorescens-adapted plasmids, became costlier in P. putida, suggesting an evolutionary trade-off. When evolved in the multi-host environment plasmids adapted to P. fluorescens without a higher cost in P. putida. CONCLUSION: Whereas evolution in a single-host environment selected for host-specialist plasmids due to a fitness trade-off, this trade-off could be circumvented in the multi-host environment, leading to the evolution of host-generalist plasmids

    Skewed genomic variability in strains of the toxigenic bacterial pathogen, Clostridium perfringens

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    Clostridium perfringens is a Gram-positive, anaerobic spore-forming bacterium commonly found in soil, sediments, and the human gastrointestinal tract. C. perfringens is responsible for a wide spectrum of disease, including food poisoning, gas gangrene (clostridial myonecrosis), enteritis necroticans, and non-foodborne gastrointestinal infections. The complete genome sequences of Clostridium perfringens strain ATCC 13124, a gas gangrene isolate and the species type strain, and the enterotoxin-producing food poisoning strain SM101, were determined and compared with the published C. perfringens strain 13 genome. Comparison of the three genomes revealed considerable genomic diversity with >300 unique "genomic islands" identified, with the majority of these islands unusually clustered on one replichore. PCR-based analysis indicated that the large genomic islands are widely variable across a large collection of C. perfringens strains. These islands encode genes that correlate to differences in virulence and phenotypic characteristics of these strains. Significant differences between the strains include numerous novel mobile elements and genes encoding metabolic capabilities, strain-specific extracellular polysaccharide capsule, sporulation factors, toxins, and other secreted enzymes, providing substantial insight into this medically important bacterial pathogen. ©2006 by Cold Spring Harbor Laboratory Press

    PhenoFam-gene set enrichment analysis through protein structural information

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    <p>Abstract</p> <p>Background</p> <p>With the current technological advances in high-throughput biology, the necessity to develop tools that help to analyse the massive amount of data being generated is evident. A powerful method of inspecting large-scale data sets is gene set enrichment analysis (GSEA) and investigation of protein structural features can guide determining the function of individual genes. However, a convenient tool that combines these two features to aid in high-throughput data analysis has not been developed yet. In order to fill this niche, we developed the user-friendly, web-based application, PhenoFam.</p> <p>Results</p> <p>PhenoFam performs gene set enrichment analysis by employing structural and functional information on families of protein domains as annotation terms. Our tool is designed to analyse complete sets of results from quantitative high-throughput studies (gene expression microarrays, functional RNAi screens, <it>etc</it>.) without prior pre-filtering or hits-selection steps. PhenoFam utilizes Ensembl databases to link a list of user-provided identifiers with protein features from the InterPro database, and assesses whether results associated with individual domains differ significantly from the overall population. To demonstrate the utility of PhenoFam we analysed a genome-wide RNA interference screen and discovered a novel function of plexins containing the cytoplasmic RasGAP domain. Furthermore, a PhenoFam analysis of breast cancer gene expression profiles revealed a link between breast carcinoma and altered expression of PX domain containing proteins.</p> <p>Conclusions</p> <p>PhenoFam provides a user-friendly, easily accessible web interface to perform GSEA based on high-throughput data sets and structural-functional protein information, and therefore aids in functional annotation of genes.</p

    Phage-Induced Expression of CRISPR-Associated Proteins Is Revealed by Shotgun Proteomics in Streptococcus thermophilus

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    The CRISPR/Cas system, comprised of clustered regularly interspaced short palindromic repeats along with their associated (Cas) proteins, protects bacteria and archaea from viral predation and invading nucleic acids. While the mechanism of action for this acquired immunity is currently under investigation, the response of Cas protein expression to phage infection has yet to be elucidated. In this study, we employed shotgun proteomics to measure the global proteome expression in a model system for studying the CRISPR/Cas response in S. thermophilus DGCC7710 infected with phage 2972. Host and viral proteins were simultaneously measured following inoculation at two different multiplicities of infection and across various time points using two-dimensional liquid chromatography tandem mass spectrometry. Thirty-seven out of forty predicted viral proteins were detected, including all proteins of the structural virome and viral effector proteins. In total, 1,013 of 2,079 predicted S. thermophilus proteins were detected, facilitating the monitoring of host protein synthesis changes in response to virus infection. Importantly, Cas proteins from all four CRISPR loci in the S. thermophilus DGCC7710 genome were detected, including loci previously thought to be inactive. Many Cas proteins were found to be constitutively expressed, but several demonstrated increased abundance following infection, including the signature Cas9 proteins from the CRISPR1 and CRISPR3 loci, which are key players in the interference phase of the CRISPR/Cas response. Altogether, these results provide novel insights into the proteomic response of S. thermophilus, specifically CRISPR-associated proteins, upon phage 2972 infection

    Metabolic reconstruction of sulfur assimilation in the extremophile Acidithiobacillus ferrooxidans based on genome analysis

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    BACKGROUND: Acidithiobacillus ferrooxidans is a gamma-proteobacterium that lives at pH2 and obtains energy by the oxidation of sulfur and iron. It is used in the biomining industry for the recovery of metals and is one of the causative agents of acid mine drainage. Effective tools for the study of its genetics and physiology are not in widespread use and, despite considerable effort, an understanding of its unusual physiology remains at a rudimentary level. Nearly complete genome sequences of A. ferrooxidans are available from two public sources and we have exploited this information to reconstruct aspects of its sulfur metabolism. RESULTS: Two candidate mechanisms for sulfate uptake from the environment were detected but both belong to large paralogous families of membrane transporters and their identification remains tentative. Prospective genes, pathways and regulatory mechanisms were identified that are likely to be involved in the assimilation of sulfate into cysteine and in the formation of Fe-S centers. Genes and regulatory networks were also uncovered that may link sulfur assimilation with nitrogen fixation, hydrogen utilization and sulfur reduction. Potential pathways were identified for sulfation of extracellular metabolites that may possibly be involved in cellular attachment to pyrite, sulfur and other solid substrates. CONCLUSIONS: A bioinformatic analysis of the genome sequence of A. ferrooxidans has revealed candidate genes, metabolic process and control mechanisms potentially involved in aspects of sulfur metabolism. Metabolic modeling provides an important preliminary step in understanding the unusual physiology of this extremophile especially given the severe difficulties involved in its genetic manipulation and biochemical analysis

    Experimental annotation of post-translational features and translated coding regions in the pathogen Salmonella Typhimurium

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    <p>Abstract</p> <p>Background</p> <p>Complete and accurate genome annotation is crucial for comprehensive and systematic studies of biological systems. However, determining protein-coding genes for most new genomes is almost completely performed by inference using computational predictions with significant documented error rates (> 15%). Furthermore, gene prediction programs provide no information on biologically important post-translational processing events critical for protein function.</p> <p>Results</p> <p>We experimentally annotated the bacterial pathogen <it>Salmonella </it>Typhimurium 14028, using "shotgun" proteomics to accurately uncover the translational landscape and post-translational features. The data provide protein-level experimental validation for approximately half of the predicted protein-coding genes in <it>Salmonella </it>and suggest revisions to several genes that appear to have incorrectly assigned translational start sites, including a potential novel alternate start codon. Additionally, we uncovered 12 non-annotated genes missed by gene prediction programs, as well as evidence suggesting a role for one of these novel ORFs in <it>Salmonella </it>pathogenesis. We also characterized post-translational features in the <it>Salmonella </it>genome, including chemical modifications and proteolytic cleavages. We find that bacteria have a much larger and more complex repertoire of chemical modifications than previously thought including several novel modifications. Our <it>in vivo </it>proteolysis data identified more than 130 signal peptide and N-terminal methionine cleavage events critical for protein function.</p> <p>Conclusion</p> <p>This work highlights several ways in which application of proteomics data can improve the quality of genome annotations to facilitate novel biological insights and provides a comprehensive proteome map of <it>Salmonella </it>as a resource for systems analysis.</p
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