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You searched for +publisher:"Duquesne University" +contributor:("Valerie Oke"). Showing records 1 – 3 of 3 total matches.

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Duquesne University

1. Hasipek, Metis. Characterization of Streptomyces coelicolor ParH in development-associated chromosome segregation.

Degree: PhD, Biological Sciences, 2016, Duquesne University

S. coelicolor uses an active chromosome partitioning system for developmentally-regulated genome segregation, which is associated with spore formation. There are four known trans-acting segregation proteins (ParA, ParB, ParJ and Scy) and cis-acting centromere-like sites (parS). parA encodes a Walker-type ATPase that is required for efficient DNA segregation and proper placement of the ParB-parS nucleoprotein complexes. A paralogue of ParA is encoded by the S. coelicolor genome, SCO1772 (named ParH), that has 45% identical residues to ParA. In S. coelicolor aerial hyphae, a ∆parH mutant produces 5% of anucleate spores. In this study, ParH was identified as a novel interaction partner of S. coelicolor ParB. However, a Walker A motif K99E substitution in ParH and removal an N-terminal extension in ParH impaired interaction between ParH and ParB, as judged by bacterial two-hybrid analyses. ParH-EGFP localization resembles the evenly-spaced localization pattern of ParH-EGFP in aerial hyphae, which might suggest that ParH colocalizes with ParB. A parH-null mutant appears to be unable to properly organize the oriC regions within a subset of prespores, as judged by ParB-EGFP foci. In this study, through a random chromosomal library screening, a novel protein that interacts with ParA and ParH was also identified. HaaA (ParH and ParA Associated protein A) is required for proper chromosome segregation and is one of the 24 signature proteins of the Actinomycetes that are not found in other bacterial lineages. A bacterial two-hybrid analysis showed that HaaA interacts with itself and interaction between ParH and ParA was through the C-terminal unstructured region. Interaction between HaaA and ParA and ParA-like proteins was conserved in other Actinomycetes, such as S. venezuelae, C. glutamicum and M. smegmatis. There was no evidence for interaction with other tested segregation proteins. In addition, a haaA insertion-deletion mutant strain revealed that loss of HaaA affected chromosome segregation (6% anucleate spores) and HaaA-EGFP localizes within spores of the mature spore chains. Together these data revealed new information to further understand chromosome segregation in S. coelicolor. Advisors/Committee Members: Joseph McCormick, Valerie Oke, Jana Vogt, Michael Seaman.

Subjects/Keywords: Chromosome Segregation

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APA (6th Edition):

Hasipek, M. (2016). Characterization of Streptomyces coelicolor ParH in development-associated chromosome segregation. (Doctoral Dissertation). Duquesne University. Retrieved from https://dsc.duq.edu/etd/1502

Chicago Manual of Style (16th Edition):

Hasipek, Metis. “Characterization of Streptomyces coelicolor ParH in development-associated chromosome segregation.” 2016. Doctoral Dissertation, Duquesne University. Accessed October 15, 2019. https://dsc.duq.edu/etd/1502.

MLA Handbook (7th Edition):

Hasipek, Metis. “Characterization of Streptomyces coelicolor ParH in development-associated chromosome segregation.” 2016. Web. 15 Oct 2019.

Vancouver:

Hasipek M. Characterization of Streptomyces coelicolor ParH in development-associated chromosome segregation. [Internet] [Doctoral dissertation]. Duquesne University; 2016. [cited 2019 Oct 15]. Available from: https://dsc.duq.edu/etd/1502.

Council of Science Editors:

Hasipek M. Characterization of Streptomyces coelicolor ParH in development-associated chromosome segregation. [Doctoral Dissertation]. Duquesne University; 2016. Available from: https://dsc.duq.edu/etd/1502


Duquesne University

2. Czapski, Tiffany R. Determination of the Expression Patterns of the Nine CSP Genes in Escherichia coli K-12 MG1655 and the Growth Defects Associated with Deletion of These Genes.

Degree: PhD, Biological Sciences, 2014, Duquesne University

Cold-shock proteins (CSPs) are a family of small nucleic acid-binding proteins. In Escherichia coli K-12, there are 9 homologous csp genes named A-I. Aside from microarray studies, transcript levels from all nine csp genes have never been assayed using the same technique. The objectives of this study were to determine when these genes are expressed, if homologous pairs are expressed the same, how many are cold-shock inducible, and if there is a ranking of importance for these genes. To answer these questions, I determined csp mRNA expression patterns for all nine csp genes during normal growth at 37°C, and after cold-shock, using quantitative real-time PCR. To uncover functional redundancies, deletion mutants were analyzed for their colony-forming ability after cold-shock, and after exposure to the chromosome decondensing agent, camphor. The results show that mRNA levels for each csp gene change with growth phase, and growth rate, and that homologous pairs are not expressed the same. The six most highly expressed csp genes in E. coli K-12 at 37°C are cspA, -B, -C, -E, -G, and -I. Transcription of cspA, -B, -G, and -I was induced after a shift to 15°C in defined minimal medium. Of the six quintuple csp deletion mutants that were created, one shows the most severe macroscopic phenotypes (TC155, cspABCEG). TC155 is cold-sensitive, and camphor-sensitive on both defined rich and defined minimal agar and only overexpression of CspC, CspE, CspG, or CspI can rescue the growth of this mutant. Taken together, these results indicate that there is some functional redundancy among the nine CSPs in E. coli K-12, but there is also a ranking of importance for these proteins in the cell. Advisors/Committee Members: Nancy Trun, Joseph McCormick, Valerie Oke, Jana Patton-Vogt.

Subjects/Keywords: Cold-shock proteins; gene expression; nucleic acid-binding proteins; qRT-PCR; RNA chaperones; stress response

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Czapski, T. R. (2014). Determination of the Expression Patterns of the Nine CSP Genes in Escherichia coli K-12 MG1655 and the Growth Defects Associated with Deletion of These Genes. (Doctoral Dissertation). Duquesne University. Retrieved from https://dsc.duq.edu/etd/449

Chicago Manual of Style (16th Edition):

Czapski, Tiffany R. “Determination of the Expression Patterns of the Nine CSP Genes in Escherichia coli K-12 MG1655 and the Growth Defects Associated with Deletion of These Genes.” 2014. Doctoral Dissertation, Duquesne University. Accessed October 15, 2019. https://dsc.duq.edu/etd/449.

MLA Handbook (7th Edition):

Czapski, Tiffany R. “Determination of the Expression Patterns of the Nine CSP Genes in Escherichia coli K-12 MG1655 and the Growth Defects Associated with Deletion of These Genes.” 2014. Web. 15 Oct 2019.

Vancouver:

Czapski TR. Determination of the Expression Patterns of the Nine CSP Genes in Escherichia coli K-12 MG1655 and the Growth Defects Associated with Deletion of These Genes. [Internet] [Doctoral dissertation]. Duquesne University; 2014. [cited 2019 Oct 15]. Available from: https://dsc.duq.edu/etd/449.

Council of Science Editors:

Czapski TR. Determination of the Expression Patterns of the Nine CSP Genes in Escherichia coli K-12 MG1655 and the Growth Defects Associated with Deletion of These Genes. [Doctoral Dissertation]. Duquesne University; 2014. Available from: https://dsc.duq.edu/etd/449


Duquesne University

3. Bennett, Jennifer Ann. Molecular Genetic Analysis of Division and Development in Streptomyces coelicolor.

Degree: PhD, Biological Sciences, 2006, Duquesne University

Here I describe both molecular and classical genetic approaches to the study of prokaryotic cell division. I detail the characterization of four cell division gene homologues: ftsL, divIC, ftsW and ftsI. FtsI, a penicillin-binding protein and transpeptidase involved specifically in septal peptidoglycan biosynthesis, is the only protein product of these four genes with a known role during cell division. I show that a null-mutation in any of the four genes resulted in a mutant with a medium-dependent division phenotype that was more severe on a rich medium. In E. coli, B. subtilis and other bacteria, these genes are essential, but in S. coelicolor they are only required for efficient division. Using phase-contrast and transmission electron microscopy, I was able to propose a role in cell division for FtsL and DivIC. In addition, I describe the development of a high efficiency, Tn5-based in vivo transposon system for the random insertional mutagenesis of Streptomyces coelicolor. This method allows high throughput screening of insertion mutants to identify novel genes involved in a variety of cellular processes. Because cell division is only required for spore formation in Streptomyces, new cell division genes can be identified by transposon mutagenesis, a strategy that would not be possible in other organisms. I have successfully conducted screens to identify transposon insertions in known developmental genes, and have also partially characterized a mutant with an interesting developmental phenotype. This mutant possessed a transposon insertion in a gene of previously unknown function, and displayed a spore shape and size defect upon examination with phase-contrast and transmission electron microscopy. Thus, I describe two different approaches to elucidate the process of cell division in S. coelicolor and other bacteria. Advisors/Committee Members: Joseph R. McCormick, David Lampe, Nancy Trun, Valerie Oke.

Subjects/Keywords: cell division; streptomyces; cytokinesis; differentiation; sporulation; transposon

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Bennett, J. A. (2006). Molecular Genetic Analysis of Division and Development in Streptomyces coelicolor. (Doctoral Dissertation). Duquesne University. Retrieved from https://dsc.duq.edu/etd/301

Chicago Manual of Style (16th Edition):

Bennett, Jennifer Ann. “Molecular Genetic Analysis of Division and Development in Streptomyces coelicolor.” 2006. Doctoral Dissertation, Duquesne University. Accessed October 15, 2019. https://dsc.duq.edu/etd/301.

MLA Handbook (7th Edition):

Bennett, Jennifer Ann. “Molecular Genetic Analysis of Division and Development in Streptomyces coelicolor.” 2006. Web. 15 Oct 2019.

Vancouver:

Bennett JA. Molecular Genetic Analysis of Division and Development in Streptomyces coelicolor. [Internet] [Doctoral dissertation]. Duquesne University; 2006. [cited 2019 Oct 15]. Available from: https://dsc.duq.edu/etd/301.

Council of Science Editors:

Bennett JA. Molecular Genetic Analysis of Division and Development in Streptomyces coelicolor. [Doctoral Dissertation]. Duquesne University; 2006. Available from: https://dsc.duq.edu/etd/301

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