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Showing 1 to 20 of 65 for “"Sigma Factor"”.
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A model for sigma factor competition in bacterial cells
… several stress-specific molecules such as sigma factors. They reversibly bind the RNA polymerase to form the so-called holoenzyme and direct it towards the appropriate stress response genes. In exponentially growing E. coli cells, the majority of the transcriptional activity is carried out …
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Sigma factor engineering for natural product synthesis in Actinoplanes sp. SE50/110
… to growth, this study mainly focused on σ factors, which are transcriptional activators that are involved in major cellular processes such as growth phase-dependent and stress response regulation. It was demonstrated in less complex bacteria that the engineering of σ factors enabled the …
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Investigation of Bacillus subtilis Sigma Factor Dynamics Using Improved Single Cell Tools
… conditions by activating alternative sigma factors. It has been shown previously that single cell approaches can reveal hidden dynamics in sigma factor activation. Here, we investigate the single cell response dynamics of the \textit{B. subtilis} extracytoplasmic function sigma …
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Regulated intramembrane proteolysis in the control of the Bacillus subtilis anti-sigma factor RsiW.
… activity of the extracytoplasmic function (ECF)-sigma factor SigW of the Gram-positive soil bacterium Bacillus subtilis is modulated by a specific membrane-bound anti-sigma factor (RsiW). Initiated most likely by cell wall stress, RsiW is degraded by the mechanism of regulated intramembrane …
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Characterization of the Sigma Factor Proteins and the Dna Binding Protein Euo of Chlamydia
… gene expression in chlamydiae: a cascade of sigma factor expression and the binding of the early stage protein EUO to DNA. </p> <p> The protein expression levels of each of the three sigma factors were monitored throughout the developmental cycle to determine if expression of the sigma …
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Structural Analysis of an RNA Polymerase Sigma Factor and Its Anti-sigma: sigma28/FLGM
<p>Eubacterial sigma (σ) factors are required during the initiation of transcription, where they play key roles in promoter recognition, melting, and transcriptional regulation, sigma is a dissociable subunit of RNA polymerase (RNAP), and sequence-specifically recognizes promoters, but only after …
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Role of the Aspartyl Protease SpoIIGA in the Compartmentalization of Sigma Factor Activation During Sporulation of Bacillus subtilis
… and larger mother cell. The transcription factor σF becomes active in the prespore, and directs the transcription of approximately 50 genes. One of those genes, paramount to this study, is spoIIR. The SpoIIR protein is exported, and localizes to the inter-membrane space of the sporulation …
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Influence of Membrane-Damaging Agents and the Sigma Factor AlgU on the Induction of the MexCD-OprJ Efflux System of Pseudomonas Aeruginosa
… fusion and RT-PCR. Since the P. aeruginosa sigma factor AlgU is responsive to envelope stress, it was of interest to ascertain whether AlgU is capable of mediating this increased mexCD-oprJ expression. Thus, the impact of AlgU loss on mexCD-oprJ expression in response to membrane-damaging …
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How bacteria tune mixed positive/negative feedback loops to generate diverse gene expression dynamics
… sensing and responding to change are alternative sigma factors. These are a type of transcription factor, and unique in that they integrate into the RNA polymerase molecule itself, often with dramatic effect on the bacterium’s transcriptional program. They exist in great diversity, both within and …
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Investigation of the regulatory interactions and dynamics between the circadian clock and sigma factors in the cyanobacterium Synechococcus elongatus
… studied the coupling of the circadian clock to sigma factor expression in Synechococcus elongatus PCC 7942 (S. elongatus), a fresh-water unicellular cyanobacterium. The core of the circadian clock of S. elongatus is composed of only three proteins, KaiA, KaiB and KaiC, but generates a 24 h …
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A small RNA regulates RpoS in the Lyme disease spirochete Borrelia burgdorferi
… non-canonical RNA chaperone Hfq. The alternative sigma factor RpoS (sigma 38 or sigma S) plays a central role in the reciprocal regulation of the virulence-associated major outer surface proteins OspC and OspA. Temperature is one of the key environmental signals controlling RpoS, but the molecular …
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A small RNA regulates RpoS in the Lyme disease spirochete Borrelia burgdorferi
… non-canonical RNA chaperone Hfq. The alternative sigma factor RpoS (sigma 38 or sigma S) plays a central role in the reciprocal regulation of the virulence-associated major outer surface proteins OspC and OspA. Temperature is one of the key environmental signals controlling RpoS, but the molecular …
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Functional analysis of the role of alternative sigma factors in Vibrio parahaemolyticus host pathogen interactions
… patterns through the use of alternative sigma factors. V. parahaemolyticus has 11 sigma factors, compared to Escherichia coli which has 7. This work examined the distribution and functionality of sigma factors in V. parahaemolyticus. Distribution analysis of V. parahaemolyticus sigma …
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Allosteric activation of periplasmic HtrA proteases
… protease, cleaves RseA, a transmembrane anti-sigma factor, causing downstream release of the [sgima]E sigma factor and transcription of stress-response genes. Each subunit of the DegS trimer contains a trypsin-like protease domain and a PDZ domain. In the absence of stress, autoinhibitory …
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Alternative regulation of the alginate algD operon by an activated AlgB in nonmucoid Pseudomonas aeruginosa is dependent on Sigma 54
… causes a mucoid phenotype, is a major virulence factor associated with chronic pulmonary infections in cystic fibrosis patients. Expression of the algD operon for alginate biosynthesis requires three major regulators in association with the ECF sigma factor, σ22, in mucoid strains that are …
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An Adaptive Approach to Gibbs’ Phenomenon
… the unwanted oscillations, we used the Lanczos sigma factor to adjust the Fourier series and we came across three cases. Out of the three, two of them failed to give us the right reconstructions because either it was removing the oscillations partially but not entirely or it was completely …
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Regulation and production of extracellular signaling molecules in Bacillus subtilis
… in B. subtilis by regulating transcription factors. I showed that the transcription of these peptide regulators is in turn controlled in part by the alternate sigma factor sigma-H. The activity of sigma-H is stimulated by nutrient starvation I determined that B. subtilis produces a putative …
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The transcriptional control of virulence gene expression in Helicobacter pylori
… adenocarcinoma. Although many of the bacterial factors associated with disease development have been analysed in some detail in the recent years, very few studies have focused so far on the mechanisms that regulate expression of these factors at the molecular level. In an attempt to obtain an …
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Mechanistic studies on transcription activation via DNA looping in a prokaryotic promoter-enhancer system
… which is associated with the alternative sigma factor sigma54 (RNAP-sigma54), and the transcription activator protein NtrC (nitrogen regulatory protein C), which binds to a remote enhancer region to the promoter. Enhancer-bound NtrC contacts the RNA polymerase at the promoter by means of …
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Investigation of the Genetic Basis of Antibiotic Resistance in Mycobacterium tuberculosis
… genotypic marker suggests that other factors, such as differential gene expression, may play a role in the development of drug resistance in M. tuberculosis. This investigation aims to both develop and evaluate rapid genotypic assays for the detection of resistance to both first- and …
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