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You searched for +publisher:"Dalhousie University" +contributor:("Dr. Frances L. Cozens"). Showing records 1 – 3 of 3 total matches.

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Dalhousie University

1. Martinez-Farina, Camilo. Investigations into the Biosynthesis, Derivatization, and Purification of Jadomycins.

Degree: MS, Department of Chemistry, 2015, Dalhousie University

Nature produces many clinically used medicines in the form of natural products. These compounds can be isolated from a variety of sources, but bacteria have been shown to be the most prolific source. The strain Streptomyces has been thoroughly investigated for such natural products, with Streptomyces venezuelae ISP5230 showing the ability to produce the clinically used antibiotic chloramphenicol, as well as the jadomycins, a family of secondary metabolites. These secondary metabolites are produced through a biosynthetic pathway where the incorporation of the amino acid into the jadomycin structure is likely non-enzymatic. This allows for jadomycins to be readily derivatized, where upwards of twenty-five derivatives have been previously isolated. This work presents the amplification of the jadomycin library through the production of novel jadomycins, as well as their further diversification through the use of synthetic derivatization. The study of jadomycins is not only important chemically, but also biologically because they have been shown to possess anti-cancerous properties. For this reason, the two synthetic derivatives were assessed for biological activities and their results are discussed herein. Investigations were also carried out to develop a method to assess biological activity by nuclear magnetic resonance, and are presented. Finally, investigations into the jadomycin purification methodology were carried out using JadX, a potential regulatory protein in the jadomycin biosynthesis, and are discussed. Advisors/Committee Members: n/a (external-examiner), Dr. Mark Stradiotto (graduate-coordinator), Dr. T. Bruce Grindley (thesis-reader), Dr. Frances L. Cozens (thesis-reader), Dr. David L. Jakeman (thesis-supervisor), Not Applicable (ethics-approval), Yes (manuscripts), Yes (copyright-release).

Subjects/Keywords: Natural Products; Jadomycin; Precursor-Directed Biosynthesis; WaterLOGSY

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APA (6th Edition):

Martinez-Farina, C. (2015). Investigations into the Biosynthesis, Derivatization, and Purification of Jadomycins. (Masters Thesis). Dalhousie University. Retrieved from http://hdl.handle.net/10222/56323

Chicago Manual of Style (16th Edition):

Martinez-Farina, Camilo. “Investigations into the Biosynthesis, Derivatization, and Purification of Jadomycins.” 2015. Masters Thesis, Dalhousie University. Accessed May 29, 2020. http://hdl.handle.net/10222/56323.

MLA Handbook (7th Edition):

Martinez-Farina, Camilo. “Investigations into the Biosynthesis, Derivatization, and Purification of Jadomycins.” 2015. Web. 29 May 2020.

Vancouver:

Martinez-Farina C. Investigations into the Biosynthesis, Derivatization, and Purification of Jadomycins. [Internet] [Masters thesis]. Dalhousie University; 2015. [cited 2020 May 29]. Available from: http://hdl.handle.net/10222/56323.

Council of Science Editors:

Martinez-Farina C. Investigations into the Biosynthesis, Derivatization, and Purification of Jadomycins. [Masters Thesis]. Dalhousie University; 2015. Available from: http://hdl.handle.net/10222/56323


Dalhousie University

2. Tovstiga, Tara. Novel Fragmentation Processes of 2-Nitrobenzenesulfonyl Amino Acid Anions.

Degree: MS, Department of Chemistry, 2013, Dalhousie University

A library of 2-nitrobenzenesulfonyl (Ns) derivatives incorporating isotopic labels and a range of structural variations was prepared and characterized to investigate mass spectrometric fragmentation processes. Deprotonated Ns amino acids were formed readily by negative mode electrospray ionization. Collision induced dissociation experiments established precursor-product ion relationships and indicated a novel loss of an aryl ortho substituent (NO2, F, Cl or Br). In total, four distinct fragmentation pathways of Ns-alpha- and Ns-beta-amino acid anions were identified using isotopic labeling, structural variations of the Ns derivatives, and collision induced dissociation of ions generated in source. Overall, the observation of specific fragmentation pathways correlated with anion structure and ionization site. However, the observation of only one of four possible fragmentation processes in the mass spectrum of the Ns derivative of an amino dicarboxylic acid indicated that functional group interactions must also be considered in the interpretation and prediction of fragmentation processes. Advisors/Committee Members: n/a (external-examiner), Dr. Mark Stradiotto (graduate-coordinator), Dr. Jean D. Burnell (thesis-reader), Dr. Frances L. Cozens (thesis-reader), Dr. Louis Ramaley (thesis-reader), Dr. Robert L. White (thesis-supervisor), Not Applicable (ethics-approval), Not Applicable (manuscripts), Not Applicable (copyright-release).

Subjects/Keywords: Chemistry; mass spectrometry; negative ion

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

APA (6th Edition):

Tovstiga, T. (2013). Novel Fragmentation Processes of 2-Nitrobenzenesulfonyl Amino Acid Anions. (Masters Thesis). Dalhousie University. Retrieved from http://hdl.handle.net/10222/35370

Chicago Manual of Style (16th Edition):

Tovstiga, Tara. “Novel Fragmentation Processes of 2-Nitrobenzenesulfonyl Amino Acid Anions.” 2013. Masters Thesis, Dalhousie University. Accessed May 29, 2020. http://hdl.handle.net/10222/35370.

MLA Handbook (7th Edition):

Tovstiga, Tara. “Novel Fragmentation Processes of 2-Nitrobenzenesulfonyl Amino Acid Anions.” 2013. Web. 29 May 2020.

Vancouver:

Tovstiga T. Novel Fragmentation Processes of 2-Nitrobenzenesulfonyl Amino Acid Anions. [Internet] [Masters thesis]. Dalhousie University; 2013. [cited 2020 May 29]. Available from: http://hdl.handle.net/10222/35370.

Council of Science Editors:

Tovstiga T. Novel Fragmentation Processes of 2-Nitrobenzenesulfonyl Amino Acid Anions. [Masters Thesis]. Dalhousie University; 2013. Available from: http://hdl.handle.net/10222/35370

3. Ruzic-Gauthier, Michael. Cleavage of duplex DNA using two-photon excitation of N-(alkoxy)pyridine thiones.

Degree: MS, Department of Chemistry, 2013, Dalhousie University

DNA photocleaving reagents are a unique class of molecules that display the ability to cleave DNA, causing strand breaks, upon exposure to an irradiation source. In terms of biological applications, achieving excitation through a two-photon absorption event provides for unique benefits that can be useful in such applications as photodynamic therapy and cell viability studies. Thus, this thesis pertains to the study of a class of photocleaving reagents that have been shown to become excited through a twophoton process during irradiation with a pulsed femtosecond laser at 775 nm. N-(Alkoxy)pyridinethiones were selected as possible oxygen-based radical generators upon irradiation at two-photon wavelengths. Experiments were carried out with pBR 322 plasmid DNA to determine if these N-(alkoxy)pyridinethiones could cause strand cleavage and if so how efficient they are in doing so. Several compounds were found to be effective DNA strand cleavers when irradiated at two-photon wavelengths, displaying the utility of two-photon excitation in biological studies. Rationale is suggested for the observed variation in cleaving efficiency based on inherent properties of the generated radicals. A second study was done to measure the two-photon cross section of the compound N-(anthracenoyloxy)pyridinethione. The two-photon cross section was found by measuring the fraction of substrate remaining after specific periods of femtosecond laser irradiation at 775 nm, and the two-photon cross section was found to be 0.051 GM. Advisors/Committee Members: n/a (external-examiner), Dr. Mark stradiotto (graduate-coordinator), Dr. Alison Thompson (thesis-reader), Dr. Frances L. Cozens (thesis-reader), Dr. Robert L. White (thesis-reader), Dr. Norman P. Schepp (thesis-supervisor), Not Applicable (ethics-approval), Not Applicable (manuscripts), Yes (copyright-release).

Subjects/Keywords: two-photon excitation; DNA cleavage

…my supervisory committee members Dr. Frances L. Cozens and Dr. Robert L. White. Aside from… 

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

APA (6th Edition):

Ruzic-Gauthier, M. (2013). Cleavage of duplex DNA using two-photon excitation of N-(alkoxy)pyridine thiones. (Masters Thesis). Dalhousie University. Retrieved from http://hdl.handle.net/10222/36323

Chicago Manual of Style (16th Edition):

Ruzic-Gauthier, Michael. “Cleavage of duplex DNA using two-photon excitation of N-(alkoxy)pyridine thiones.” 2013. Masters Thesis, Dalhousie University. Accessed May 29, 2020. http://hdl.handle.net/10222/36323.

MLA Handbook (7th Edition):

Ruzic-Gauthier, Michael. “Cleavage of duplex DNA using two-photon excitation of N-(alkoxy)pyridine thiones.” 2013. Web. 29 May 2020.

Vancouver:

Ruzic-Gauthier M. Cleavage of duplex DNA using two-photon excitation of N-(alkoxy)pyridine thiones. [Internet] [Masters thesis]. Dalhousie University; 2013. [cited 2020 May 29]. Available from: http://hdl.handle.net/10222/36323.

Council of Science Editors:

Ruzic-Gauthier M. Cleavage of duplex DNA using two-photon excitation of N-(alkoxy)pyridine thiones. [Masters Thesis]. Dalhousie University; 2013. Available from: http://hdl.handle.net/10222/36323

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