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 20 of 24 for “"sigma factors"”.
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Role of Extracytoplasmic Function Sigma Factors in Porphyromonas gingivalis
… of transcription which involves the alternative sigma factors. Extracytoplasmic function (ECF) sigma factors are the largest group of alternative sigma factors that play a major role in bacterial response to environmental stress conditions. Here we characterize the σ-70 factor, SigH and SigG, the …
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Sporulation and enterotoxin regulation by sigma factors in Clostridium perfringens
… the forespore. The cell-specific RNA polymerase sigma factors coordinate the development of the differentiating cell. These sigma factors are Ï F, Ï E, Ï G, and Ï K. The C. perfringens cpe gene, encoding the enterotoxin CPE, is transcribed from three promoters, P1, P2, and P3. P2 and P3 were …
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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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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 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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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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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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Characterization of major virulence regulators of Erwinia amylovora
… secretion system (T3SS) are two major virulence factors in E. amylovora. However, how these virulence factors are regulated is not completely understood. In bacteria, gene expression is mainly regulated at the transcription initiation level and its core RNA polymerase (RNAP) requires sigma …
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Microprocessor applications to the phenomena associated with high-voltage transmission line transients
… affects global response.<br/><br/>Experimental Sigma Factors, analogous to those developed in Fourier Transform analysis, have been devised to locally average the digitised uncompensated line response. They have been applied to uncompensated line receiving-end waveforms resulting from ideal and …
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Structural and Computational Studies of RNA Polymerase
… element recognition by domain 4 of the Group IV sigma factors, revealing that conserved positions within -35 element induce an AA/TT-tract like DNA geometry, allowing for indirect promoter recognition despite the absence of direct protein/DNA interactions with several highly conserved DNA bases. …
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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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Requirements for Compartmentalization of Penicillin-Binding Proteins during Sporulation in Bacillus subtilis
… by coordinated expression of different sigma factors that recognize specific promoters in each compartment. The functional and compartmental specificity of individual penicillin-binding proteins from the different classes of PBP's were examined during sporulation in B. subtilis. Analyses …
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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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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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Phenotypic diversity as a tool to guide and optimize random strain improvement approaches
… laboratory through mutagenesis of the principal sigma factor, sigma D. Initially, we explored new targets for transcriptional engineering. Using error-prone PCR, we constructed libraries of several stress-related sigma factors in Escherichia coli (sigma S, sigma E, and sigma H) and screened them …
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How did Listeria monocytogenes become pathogenic?
… The areas I personally investigated, namely, sigma factors and stationary phase functions, are also presented. L. monocytogenes and L. innocua both possess surprisingly few sigma factors: SigA, SigB, SigH, SigL, and an extra-cytoplasmic function type sigma factor (SigECF). The stationary phase …
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Alternative regulation of the alginate algD operon by an activated AlgB in nonmucoid Pseudomonas aeruginosa is dependent on Sigma 54
… major regulators in association with the ECF sigma factor, σ22, in mucoid strains that are typically defective in anti-sigma factor, MucA. One such algD regulator is AlgB, a member of the NtrC family of two-component systems, which typically utilize σ54. However, neither σ54 nor the cognate …
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THE ROLE OF THE PARTNER SWITCHING MECHANISM IN REGULATION OF THE CHLAMYDIAL DEVELOPMENTAL CYCLE
… into phenotypic changes via regulation of sigma28. The putative chlamydial PSM is composed of two sensor phosphatases (SPs: RsbU and CTL0852), two anti-anti-sigma factors (AASFs: RsbV1 and RsbV2), an anti-sigma factor (ASF: RsbW), and sigma28. Using the Bacterial Adenylate Cyclase Two …
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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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Identification and Characterization of Flagellar Co-expressed Determinants (Feds) of Campylobacter jejuni
… flagellar genes is dependent on two alternative sigma factors, σ54 and σ28. Μany rod and hook genes are dependent on σ54 for expression, whereas σ28 is involved in the expression of the major flagellin and other filament genes. We investigated the σ28 regulon and identified five genes that are …
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