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You searched for +publisher:"University of Alabama – Birmingham" +contributor:("Bej, Asim <br>"). Showing records 1 – 3 of 3 total matches.

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1. Heath, Cara Hope. Determinants that confer stop codon specificity to Tetrahymena thermophila eRF1.

Degree: MS, 2007, University of Alabama – Birmingham

In eukaryotes, translation termination is a process which is initiated by the presence of a stop codon in the A site of the ribosome and mediated by the binding of a release factor (eRF1). In most eukaryotes, any one of three stop codons UGA, UAG, or UAA, is required for the binding of eRF1. However some organisms, such as the ciliates, have diverged from this universal coding. In one type of ciliate species, Tetrahymena thermophila, UAA and UAG are no longer recognized as stop codons and now both encode a glutamine residue. It was previously thought that domain 1 of eRF1 is solely responsible for the stop codon specificity in eukaryotes. Through fusion of Tetrahymena domain 1 to domains 2 and 3 of the yeast Saccharomyces cerevisiae (Tt1/Sc23), it was shown that Tetrahymena’s domain 1 recognized all three stops when expressed in yeast cells. This suggests that other domains of Tetrahymena eRF1 may be involved in restricting stop codon recognition. In order to determine what region of Tetrahymena’s eRF1 is linked to their altered recognition, new fusion proteins were made with increasing amounts of Tetrahymena eRF1. The results of a fusion protein with domains 1 and 2 or domain 3 from Tetrahymena (Tt12/Sc3 or Sc12/Tt3, respectively) indicate that domains 2 and 3 each reduced the ability of domains 1 to recognize UAG and UAA. The complete Tetrahymena eRF1 was unable to support growth in an eRF1 knockout strain. Analysis in the presence of the second Tetrahymena release factor, eRF3 which has a GTPase domain required for the proper function of the intact Tetrahymena eRF1, also did not restore function of Tetrahymena eRF1, suggesting that the full length eRF1 from this organism may not interact properly with yeast ribosomes.

M.S.

viii, 42 p. : digital, PDF file, col. ill.

Biology

Natural Sciences and Mathematics

erfi translation termination ciliates

UNRESTRICTED

Advisors/Committee Members: Bedwell, David, Bej, Asim <br>, Keeling, Kim.

Subjects/Keywords: Tetrahymena  – Genetics <; br>; Saccharomyces cerevisiae  – Genetics <; br>; Genetic translation.

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

APA (6th Edition):

Heath, C. H. (2007). Determinants that confer stop codon specificity to Tetrahymena thermophila eRF1. (Masters Thesis). University of Alabama – Birmingham. Retrieved from http://contentdm.mhsl.uab.edu/u?/etd,77

Chicago Manual of Style (16th Edition):

Heath, Cara Hope. “Determinants that confer stop codon specificity to Tetrahymena thermophila eRF1.” 2007. Masters Thesis, University of Alabama – Birmingham. Accessed December 05, 2019. http://contentdm.mhsl.uab.edu/u?/etd,77.

MLA Handbook (7th Edition):

Heath, Cara Hope. “Determinants that confer stop codon specificity to Tetrahymena thermophila eRF1.” 2007. Web. 05 Dec 2019.

Vancouver:

Heath CH. Determinants that confer stop codon specificity to Tetrahymena thermophila eRF1. [Internet] [Masters thesis]. University of Alabama – Birmingham; 2007. [cited 2019 Dec 05]. Available from: http://contentdm.mhsl.uab.edu/u?/etd,77.

Council of Science Editors:

Heath CH. Determinants that confer stop codon specificity to Tetrahymena thermophila eRF1. [Masters Thesis]. University of Alabama – Birmingham; 2007. Available from: http://contentdm.mhsl.uab.edu/u?/etd,77

2. Philpott, Rachel. Identification of the function of Rv0194 in mycobacterium tuberculosis.

Degree: MS, 2009, University of Alabama – Birmingham

Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis (TB), has become increasingly resistant to antibiotics due to the lack of new drugs, poor treatment compliances in certain regions, and the increase of co-infections with HIV/AIDS. Multi-drug efflux pumps and a highly impermeable outer membrane are predominant factors that contribute to its intrinsic drug resistance. A better understanding of the molecular mechanisms of Mtb antibiotic resistance is needed. A transposon library in Mycobacterium bovis BCG contained a mutant with an in-sertion upstream of the gene bcg0231. This mutant overexpressed bcg0231 and was ex-tremely resistant to ampicillin, chloramphenicol, and streptomycin. Expression of the identical homolog Rv0194 of Mtb in the model organism M. smegmatis increased resis-tance to multiple drugs via increased drug efflux. Rv0194 is similar to other ABC trans-porters and, considering the increased resistance to ampicillin of M. bovis BCG and M. smegmatis upon overexpression of Rv0194, we concluded that Rv0194 is a novel multi-drug efflux pump and likely functions as the inner membrane component of a multi-component drug efflux system capable of effluxing drugs across two membranes and out of the cell. To begin accessing drug resistance in mycobacteria, accurate antibiotic suscepti-bility assays must first be established and validated. The Nitrate Reductase Assay (NRA) was evaluated and compared to the Microplate Alamar Blue Assay. The NRA proved to be a more advantageous assay when studying Mtb due to time, ease of use, and materials factors. To examine the role of Rv0194 in the antibiotic resistance of Mtb, an rv0194 ex-pression plasmid was constructed. However, the NRA showed only minor increases in drug resistance. Possible explanations include the lack of upregulation of other proteins in the multi-component efflux system. Gfp fluorescence was measured in Mtb using a plasmid expressing a rv0194-gfp fusion demonstrating that Rv0194 is expressed. An unmarked rv0194 deletion mutant of Mtb was constructed. The NRA did not reveal any difference in resistance to ampicillin, chloramphenicol, and streptomycin when Rv0194 was absent. These results suggest that Mtb is able to compensate for the loss of Rv0194 by using one or several other drug efflux pumps.

M.S.

1 online resource (xi, 64 p.) : ill. (chiefly col.)

Biology

College of Arts and Sciences

UNRESTRICTED

Advisors/Committee Members: Niederweis, Michael, Bej, Asim <br>, Ghanta, Vithal.

Subjects/Keywords: Mycobacterium tuberculosis  – Genetic aspects <; br>; Multidrug-resistant tuberculosis  – Genetic aspects

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

APA (6th Edition):

Philpott, R. (2009). Identification of the function of Rv0194 in mycobacterium tuberculosis. (Masters Thesis). University of Alabama – Birmingham. Retrieved from http://contentdm.mhsl.uab.edu/u?/etd,925

Chicago Manual of Style (16th Edition):

Philpott, Rachel. “Identification of the function of Rv0194 in mycobacterium tuberculosis.” 2009. Masters Thesis, University of Alabama – Birmingham. Accessed December 05, 2019. http://contentdm.mhsl.uab.edu/u?/etd,925.

MLA Handbook (7th Edition):

Philpott, Rachel. “Identification of the function of Rv0194 in mycobacterium tuberculosis.” 2009. Web. 05 Dec 2019.

Vancouver:

Philpott R. Identification of the function of Rv0194 in mycobacterium tuberculosis. [Internet] [Masters thesis]. University of Alabama – Birmingham; 2009. [cited 2019 Dec 05]. Available from: http://contentdm.mhsl.uab.edu/u?/etd,925.

Council of Science Editors:

Philpott R. Identification of the function of Rv0194 in mycobacterium tuberculosis. [Masters Thesis]. University of Alabama – Birmingham; 2009. Available from: http://contentdm.mhsl.uab.edu/u?/etd,925

3. Dodd, Keela. The molecular biology of temperature-dependent sex determination in reptiles.

Degree: PhD, 2007, University of Alabama – Birmingham

Temperature-dependent sex determination (TSD) is a type of environmental sex determination in which the egg’s incubation temperature determines the sex of the embryo. The exact physiology of TSD is not yet understood. Hormones and temperature-triggered genes have been hypothesized to play a role. This study evaluates putative male and female factors that may play a role in TSD. Regarding female factors, this study evaluates clutch sensitivity to estradiol-17?? and an aromatase inhibitor, and estradiol-17??’s potential role in müllerian duct differentiation. Regarding male factors, this study also quantifies SOX9 mRNA during TSD in untreated and estradiol-17?? treated embryos. In the evaluation of clutch sensitivity to estradiol-17?? and fadrozole, results showed clutch sensitivity to both chemicals. Clutch sex ratios of treated eggs ranged from 100% male to 100% female and exhibited significant inter-clutch variation. The current study found that müllerian duct development is estradiol-17?? sensitive. Estradiol-17?? blocks development of the müllerian duct if applied before the duct’s differentiation began. If differentiation had begun, estradiol-17?? caused hypertrophy in the differentiated portion, but prevented further differentiation of the müllerian duct in more caudal regions. SOX9 was chosen for the gene expression portion of the study because it is involved in testis differentiation in all vertebrates studied. Portions of turtle SOX9 were cloned in order to develop a semi-quantitative real-time PCR for examining SOX9 expression before, during, and after TSD. Results showed no significant difference in SOX9 expression levels between male-producing temperature and female-producing temperature during the thermosensitive period of sex determination, but a significant increase was detected after the thermosensitive period during a time when the testes were differentiating. SOX9 was also evaluated in estradiol-17?? treated embryos. Embryos incubated at male-producing temperatures and treated with estradiol-17?? produce females. Adrenalkidney-gonad complexes were dissected from embryos at developmental stages corresponding to SOX9 upregulation in males. Results showed a downregulation of SOX9 at stage 23, the time of testis differentiation, but showed male SOX9 levels at stage 26. This implies that estradiol-17?? downregulation of SOX9 at stage 23 is sufficient for ovary formation and that SOX9 activity may be time-specific and temperature-dependent.

x, 67 p. : ill. (some col.), facsims., digital, PDF file.

Biology

Natural Sciences and Mathematics

Estrogen Clutch sensitivity Inter-clutch variation Temperature-dependent sex determination SOX9

UNRESTRICTED

Advisors/Committee Members: Wibbels, Thane, Bej, Asim <br>, Hines, Gene <br>, Watson, Douglas <br>, Weigent, Douglas.

Subjects/Keywords: Red-eared slider  – Embryos <; br>; Sex determination, Genetic <; br>; Red-eared slider  – Reproduction  – Effect of temperature on <; br>; Estradiol  – Physiological effect <; br>; Aromatase  – Inhibitors  – Physiological effect <; br>; Transcription factors  – Physiological effect

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

APA (6th Edition):

Dodd, K. (2007). The molecular biology of temperature-dependent sex determination in reptiles. (Doctoral Dissertation). University of Alabama – Birmingham. Retrieved from http://contentdm.mhsl.uab.edu/u?/etd,317

Chicago Manual of Style (16th Edition):

Dodd, Keela. “The molecular biology of temperature-dependent sex determination in reptiles.” 2007. Doctoral Dissertation, University of Alabama – Birmingham. Accessed December 05, 2019. http://contentdm.mhsl.uab.edu/u?/etd,317.

MLA Handbook (7th Edition):

Dodd, Keela. “The molecular biology of temperature-dependent sex determination in reptiles.” 2007. Web. 05 Dec 2019.

Vancouver:

Dodd K. The molecular biology of temperature-dependent sex determination in reptiles. [Internet] [Doctoral dissertation]. University of Alabama – Birmingham; 2007. [cited 2019 Dec 05]. Available from: http://contentdm.mhsl.uab.edu/u?/etd,317.

Council of Science Editors:

Dodd K. The molecular biology of temperature-dependent sex determination in reptiles. [Doctoral Dissertation]. University of Alabama – Birmingham; 2007. Available from: http://contentdm.mhsl.uab.edu/u?/etd,317

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