5 research outputs found

    Genome-wide analysis of myxobacterial two-component systems: genome relatedness and evolutionary changes

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    BACKGROUND: Two-component systems (TCSs) are abundant prokaryotic signaling pathways, whose evolution is of particular importance because of their role in bacterial pathogenicity. Comparative genomics can provide important insights into the evolution of these genes, but inferences are dependent on the relatedness of the compared genomes. This study investigated the relationship between evolutionary distance and TCS evolution in myxobacterial genomes, of which there are several sequenced examples, of varying relatedness, and which encode large numbers of TCSs.METHODS: Myxobacterial TCS gene sets were compared, orthologues defined, and changes in TCS properties such as gene organisation, domain architecture and size identified.RESULTS: Genome relatedness/evolutionary distance was found to have a large effect on the apparent frequency of evolutionary events affecting TCS genes, but not on the relative dominance of different types of mutations. Large (≥1 gene) indels were the most common changes, often giving rise to gene organisation changes. Smaller indels were also common, sometimes changing domain architecture, and/or leading to pseudogene formation. Individuality of myxobacterial TCS gene sets seems primarily due to lineage specific gene loss. However, there is also evidence of extensive acquisition of genes by lateral transfer, with gene duplication also creating new TCS genes.CONCLUSIONS: This study provides catalogues of myxobacterial TCS gene sets and their orthology relationships, benchmarked against genome relatedness. It also provides insights into the relationship between evolutionary distance and the inference of TCS estudies of TCS evolution beyond the myxobacteriavolution, which may be important for studies of TCS evolutiThe online version of this articleon beyond the myxobacteria.</p

    Procalcitonin impairs liver cell viability and function in vitro: A potential new mechanism of liver dysfunction and failure during sepsis?

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    Purpose. Liver dysfunction and failure are severe complications of sepsis and result in poor outcome and increased mortality. The underlying pathologic mechanisms of hepatocyte dysfunction and necrosis during sepsis are only incompletely understood. Here, we investigated whether procalcitonin, a biomarker of sepsis, modulates liver cell function and viability. Materials and Methods. Employing a previously characterized and patented biosensor system evaluating hepatocyte toxicity in vitro, human hepatocellular carcinoma cells (HepG2/C3A) were exposed to 0.01-50 ng/mL procalcitonin for 2 x 72h and evaluated for proliferation, necrosis, metabolic activity, cellular integrity, microalbumin synthesis, and detoxification capacity. Acetaminophen served as positive control. For further standardization, procalcitonin effects were confirmed in a cellular toxicology assay panel employing L929 fibroblasts. Data were analyzed using ANOVA/Tukey's test. Results. Already at concentrations as low as 0.25 ng/mL, procalcitonin induced HepG2/C3A necrosis (P < 0.05) and reduced metabolic activity, cellular integrity, synthesis, and detoxification capacity (all P < 0.001). Comparable effects were obtained employing L929 fibroblasts. Conclusion. We provide evidence for procalcitonin to directly impair function and viability of human hepatocytes and exert general cytotoxicity in vitro. Therapeutical targeting of procalcitonin could thus display a novel approach to reduce incidence of liver dysfunction and failure during sepsis and lower morbidity and mortality of septic patients

    Genetische und pathologische Linkshändigkeit als möglicher ursächlicher und prognostischer Faktor für Stottern

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    Für das Auftreten von Stottern sind disponierende, auslösende und chronifizierende Faktoren bedeutungsvoll. Unter den Dispositionen werden in der Literatur immer wieder veränderte cerebrale Dominanzverhältnisse diskutiert. Dies stützt sich unter anderem auf die Beobachtung zahlreicher Forscher über eine erhöhte Inzidenz von Linkshändigkeit bei Stotterern, denn Linkshändigkeit ist das am leichtesten erfassbare Beispiel für veränderte cerebrale Dominanz. In der hier vorgestellten Studie wurden die Fragen untersucht, ob Links- bzw. Nichtrechtshändigkeit auch vermehrt bei entwicklungsunflüssigen bzw. stotternden Kindern im Vorschulalter auftritt, diese pathologischer oder genetischer Natur ist und ob Handpräferenzen Rückschlüsse auf die Manifestation von chronischem Stottern im Kindesalter zulassen
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