Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 17 of 17 for “"alternative sigma factor"”.
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How bacteria tune mixed positive/negative feedback loops to generate diverse gene expression dynamics
… systems for 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, …
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A small RNA regulates RpoS in the Lyme disease spirochete Borrelia burgdorferi
… a 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 …
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A small RNA regulates RpoS in the Lyme disease spirochete Borrelia burgdorferi
… a 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 …
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H-NS Counter-silencing as a Primary Regulatory Mechanism of Curli Gene Expression in Salmonella Typhimurium
… previous studies have implicated a role of the alternative sigma factor σS in directly disrupting H-NS silencing, our system reveals that σS plays a more indirect role, acting through transcriptional regulators such as CsgD, IHF, and MlrA. I have identified an essential role of CsgD as a direct …
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Host-pathogen interactions in the innate immune response of the nematode Caenorhabditis elegans
… to those involved during pathogenesis in alternative animal hosts or mechanisms which are, thus far, unique to the worm. In this thesis, we present data that describes an immunological balance in C. elegans, whereby heightened tolerance to one pathogen, the enteric bacteria Salmonella …
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The roles of secondary metabolites in microcystis inter-strain interactions
… on transcriptional regulators such as the alternative sigma factor SigE, which in return captures an essential role in sugar catabolism and redox-state regulation. For the purpose of simulating community conditions as found in the field, Microcystis colonies are isolated from the eutrophic …
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CONTRIBUTIONS OF SIGMA-B AND PRFA TO STRESS RESPONSE AND VIRULENCE GENE EXPRESSION IN LISTERIA MONOCYTOGENES
… of stress response and virulence genes. The alternative sigma factor sigmaB is a global regulator of genes active under environmental stress conditions and during stationary phase growth. I identified a large portion of the genes regulated by sigmaB using a promoter consensus sequence search …
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Analysis of alkali-inducible genes of Bacillus subtilis
… While most of them are under the control of the alternative sigma factor (sigmaW), the remaining genes are under the control of one or more unknown regulator(s). By their signature, two of them kipR and yvdT code for regulatory proteins, while pspA, member of the sigmaW regulon, encodes another …
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OspC in the pathogenesis of Borrelia burgdorferi
… down-regulation of OspC is achieved by the rpoS alternative sigma factor and by an unidentified repressor, respectively. Several truncated versions of OspC were tested in an OspC-deficient background to better understand the role of the amino acid sequences deleted. Structural deletions of 5 to …
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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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Mechanistic studies on transcription activation via DNA looping in a prokaryotic promoter-enhancer system
… RNA polymerase, 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 …
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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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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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Functional analysis of the role of alternative sigma factors in Vibrio parahaemolyticus host pathogen interactions
… gene expression 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. …
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The contribution of competence system to the virulence of Streptococcus pneumoniae
… attenuates the expression of two virulence factors, CbpD and LytA during competence induction in a concentration-dependent manner. Inhibition of LytA and CbpD by CSP1-E1A reveals the possibility of using this peptide analog to attenuate pneumococcal infection. I examined whether CSP1-E1A …
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THE SUBTLE BIOFILM REGULATION IN ESCHERICHIA COLI: CSGD AND THE YDDV-DOS OPERON
… the expression modulation of the major adhesion factors in Escherichia coli; in particular I focused on the role of GGDEF and EAL proteins, on their modulation in E. coli biofilm formation in response to environmental signals and on regulation of curli fibers, cellulose and …
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Molecular dissection of competence regulated virulence in Streptococcus pneumoniae
… by two identical redundant genes, ComX is an alternative sigma factor which activates the expression of 80 “late” genes, 16 of which are required for DNA uptake and recombination. Some of the proteins encoded by the “late” competence genes, including LytA, CbpD, and CibAB, are capable of …