Evolution of antibiotic resistance in microbes is frequently achieved by acquisition of spontaneous mutations during antimicrobial therapy. Here we demonstrate that inactivation of a central regulator of iron homeostasis (fur) facilitates laboratory evolution of ciprofloxacin resistance in Escherichia coli. To decipher the underlying molecular mechanisms, we first performed a global transcriptome analysis and demonstrated a substantial reorganization of the Fur regulon in response to antibiotic treatment. We hypothesized that the impact of Fur on evolvability under antibiotic pressure is due to the elevated intracellular concentration of free iron and the consequent enhancement of oxidative damage-induced mutagenesis. In agreement with expectations, over-expression of iron storage proteins, inhibition of iron transport, or anaerobic conditions drastically suppressed the evolution of resistance, while inhibition of the SOS response-mediated mutagenesis had no such effect in fur deficient population. In sum, our work revealed the central role of iron metabolism in de novo evolution of antibiotic resistance, a pattern that could influence the development of novel antimicrobial strategies.
Perturbation of iron homeostasis promotes the evolution of antibiotic resistance.
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View SamplesIt has been unclear whether ischemic stroke induces neurogenesis or neuronal DNA-rearrangements in the human neocortex. We show here that neither is the case, using immunohistochemistry, transcriptome-, genome- and ploidy-analyses, and determination of nuclear bomb test-derived 14C-concentration in neuronal DNA. A large proportion of cortical neurons display DNA-fragmentation and DNA-repair short time after stroke, whereas neurons at chronic stages after stroke show DNA-integrity, demonstrating the relevance of an intact genome for survival. Overall design: Analyze of potential fusion transcripts in 13 samples, seven cortical ischemic stroke tissue and six control cortex, by deep sequencing using Illumina HiSeq 2000
The age and genomic integrity of neurons after cortical stroke in humans.
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View SamplesThe STOX1 transcription factor has been involved in a complex human disease of pregnancy, preeclampsia, in human families, and mouse models. However, its mode of action is still largely unknown. Overexpression of either the long (STOX1A) or the short (STOX1B) isoform was obtained in the BeWo villous trophoblast model, a cell line able to fuse in syncytiotrophoblast following induction by forskolin treatment. The effects at the transcriptional level are evaluated in every condition.
Molecular Mechanisms of Trophoblast Dysfunction Mediated by Imbalance between STOX1 Isoforms.
Cell line, Treatment
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