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You searched for +publisher:"Georgia Tech" +contributor:("Dr. Donald Doyle"). Showing records 1 – 3 of 3 total matches.

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1. Wu, Di. Discovery and characterization of a signaling molecule regulating somatic embryogenesis in loblolly pine.

Degree: PhD, Chemistry and Biochemistry, 2008, Georgia Tech

myo-Inositol-1,2,3,4,5,6-hexakisphosphate (InsP6), also called phytic acid, is ubiquitous in eukaryotic cells and the most abundant inositol phosphate derivative. Loblolly pine (LP, Pinus taeda) constitutes the primary commercial species in the southern forest of U.S. Somatic embryogenesis (SE) is an effective technique to maintain the desirable genetic composition of the progeny and to accomplish the efficiency of propagation. SE can also serve as a tool for study of plant development. Unlike angiosperm embryos with attached cotyledons as seed storage organs, the diploid conifer embryo is surrounded by the unattached haploid female gametophyte (FG). In LP SE, FG tissue is absent in the embryogenic tissue culture. We found that extracts from early-stage FG stimulate growth and multiplication of early-stage somatic embryos, whereas FG water extracts from late stage contain substance(s) inhibitory to early-stage somatic embryo growth (DeSilva et al., 2007). We now present the isolation and identification of the inhibitory substance as InsP6 by means of water extraction, two gel filtrations and two ion exchange FPLC chromatographies. The results represent the first complete structural characterization of InsP6 from a natural product using LC/MS, LC/MS/MS, exact MS, 1D- and 2D-NMR analyses. We also report that there is a good correlation between the amount of InsP6 purified from FG tissue (1.3 nmoles per full-term FG) and the amount of InsP6 which inhibits somatic embryo growth. This novel approach of isolating and characterizing InsP6 from plant tissue, and investigating its role on SE can allow us to improve SE technology by circumventing current bottleneck, to elucidate enigmatic functions of InsP6 in plants, and most importantly, to utilize this molecule properly. Advisors/Committee Members: Dr. Sheldon May (Committee Chair), Dr. Donald Doyle (Committee Member), Dr. Gerald Pullman (Committee Member), Dr. James Powers (Committee Member), Dr. Nicholas Hud (Committee Member).

Subjects/Keywords: NMR; LC/MS; FPLC; Female gametophyte; Loblolly pine; Somatic embryogenesis; Myo-inositol hexakisphosphate; Loblolly pine; Somatic embryogenesis; Phytic acid

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APA (6th Edition):

Wu, D. (2008). Discovery and characterization of a signaling molecule regulating somatic embryogenesis in loblolly pine. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/28252

Chicago Manual of Style (16th Edition):

Wu, Di. “Discovery and characterization of a signaling molecule regulating somatic embryogenesis in loblolly pine.” 2008. Doctoral Dissertation, Georgia Tech. Accessed January 17, 2021. http://hdl.handle.net/1853/28252.

MLA Handbook (7th Edition):

Wu, Di. “Discovery and characterization of a signaling molecule regulating somatic embryogenesis in loblolly pine.” 2008. Web. 17 Jan 2021.

Vancouver:

Wu D. Discovery and characterization of a signaling molecule regulating somatic embryogenesis in loblolly pine. [Internet] [Doctoral dissertation]. Georgia Tech; 2008. [cited 2021 Jan 17]. Available from: http://hdl.handle.net/1853/28252.

Council of Science Editors:

Wu D. Discovery and characterization of a signaling molecule regulating somatic embryogenesis in loblolly pine. [Doctoral Dissertation]. Georgia Tech; 2008. Available from: http://hdl.handle.net/1853/28252


Georgia Tech

2. Das, Prolay. Long-Range Charge Transfer in Plasmid DNA Condensates and DNA-Directed Assembly of Conducting Polymers.

Degree: PhD, Chemistry and Biochemistry, 2007, Georgia Tech

Long-distance radical cation transport was studied in DNA condensates where linearized pUC19 plasmid was ligated to an oligomer and transformed into DNA condensates with spermidine. DNA condensates were detected by Dynamic Light Scattering and observed by Transmission Electron Microscopy. Introduction of charge into the condensates causes long-distance charge migration, which is detected by reaction at the remote guanines. The efficiency of charge migration in the condensate is significantly less than it is for the corresponding oligomer in solution. This result is attributed to a lower mobility for the migrating radical cation in the condensate, caused by inhibited formation of charge-transfer-effective states. Radical cation transport was also studied in DNA condensates made from an oligomer sandwiched between two linearized plasmids by double ligation. Unlike the single ligated plasmid condensates, the efficiency of charge migration in the double ligated plasmid-condensates is high, indicative of local structural and conformational transformation of the DNA duplexes. Organic monomer units having extended ð-conjugation as part of a long conducting polymer was synthesized and characterized. The monomer units were covalently attached to particular positions in DNA oligonucleotides by either the convertible nucleotide approach or by phosphoramidite chemistry. Successful attachment of the monomer units to DNA were confirmed by mass spectral analysis. The DNA-conjoined monomer units can self assemble in the presence of complementary sequences which act as templates that can control polymer formation and structure. By this method the para-direction of the polymer formation can be enforced and may be used to generate materials having nonrecurring, irregular structures. Advisors/Committee Members: Dr. Gary B. Schuster (Committee Chair), Dr. David M. Collard (Committee Member), Dr. Donald Doyle (Committee Member), Dr. Marcus Weck (Committee Member), Dr. Uzi Landman (Committee Member).

Subjects/Keywords: DNA charge transfer; Conducting polymers; Radical cation; Self assembly; Conducting polymers; Charge tranfer in biology; Cations; DNA; Self-organizing systems

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

APA (6th Edition):

Das, P. (2007). Long-Range Charge Transfer in Plasmid DNA Condensates and DNA-Directed Assembly of Conducting Polymers. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/19856

Chicago Manual of Style (16th Edition):

Das, Prolay. “Long-Range Charge Transfer in Plasmid DNA Condensates and DNA-Directed Assembly of Conducting Polymers.” 2007. Doctoral Dissertation, Georgia Tech. Accessed January 17, 2021. http://hdl.handle.net/1853/19856.

MLA Handbook (7th Edition):

Das, Prolay. “Long-Range Charge Transfer in Plasmid DNA Condensates and DNA-Directed Assembly of Conducting Polymers.” 2007. Web. 17 Jan 2021.

Vancouver:

Das P. Long-Range Charge Transfer in Plasmid DNA Condensates and DNA-Directed Assembly of Conducting Polymers. [Internet] [Doctoral dissertation]. Georgia Tech; 2007. [cited 2021 Jan 17]. Available from: http://hdl.handle.net/1853/19856.

Council of Science Editors:

Das P. Long-Range Charge Transfer in Plasmid DNA Condensates and DNA-Directed Assembly of Conducting Polymers. [Doctoral Dissertation]. Georgia Tech; 2007. Available from: http://hdl.handle.net/1853/19856


Georgia Tech

3. Gotz, Marion Gabriele. Design, synthesis, and evaluation of irreversible peptidyl inhibitors for clan CA and clan CD cysteine proteases.

Degree: PhD, Chemistry and Biochemistry, 2004, Georgia Tech

Cysteine proteases are a class of proteolytic enzymes, which are involved in a series of metabolic and catabolic processes, such as protein turnover, digestion, blood coagulation, apoptosis, fertilization and cell differentiation, and the immune response system. The development of novel potent and selective inhibitors for cysteine proteases has therefore gained increasing attention among medicinal chemists. In this thesis we have reported the design, synthesis, and evaluation of several peptidyl inhibitors for clan CA and clan CD cysteine proteases. We have continued the investigation of dipeptidyl vinyl sulfones as potent and selective inhibitors for dipeptidyl peptidase I (DPPI), a lysosomal cysteine protease, which is involved in the processing of intracellular proteases, such as granzymes. We have found that DPPI tolerates negatively charged amino acid residues in the P2 position with inhibition rates of 7,600 M-1s-1. Dipeptidyl vinyl sulfones with positively charged amino acid residues at the P1 position, however, do not inhibit DPPI at all. A second project focused on the epoxidation of the double bond of the vinyl sulfone moiety of the dipeptidyl vinyl sulfones. Instead of epoxidizing the double bond, we found that an isomerization had occurred. The newly formed compounds were determined to be allyl sulfones. We tested this new class of inhibitors with clan CA proteases and obtained inhibition rates of 560 M-1s-1 for Cbz-Leu-Phe-AS-Ph with calpain I. Two new classes of compounds for the clan CD protease S. mansoni legumain were designed, synthesized, and evaluated. Aza-peptidyl epoxides were found to be potent and selective inhibitors of S. mansoni legumain with IC50’s as low as 45 nM. Aza-peptide Michael acceptors were derived from the aza-peptide epoxide design and synthesized in an analogous fashion. The aza-peptide Michael acceptors inhibited S. mansoni legumain with even lower IC50’s, as low as 10 nM. However, the aza-peptide Michael acceptors react with thioalkylating agents contained in the buffer, such as DTT. The rates of degradation were determined spectroscopically, and half-lives of 3 to 20 minutes were measured. This observation gave us insights into the enzymatic mechanism and allowed us to determine the point of attack for the legumain active site cysteine thiol. Advisors/Committee Members: Dr. James C. Powers (Committee Chair), Dr. Donald Doyle, Dr. Nicholas Hud, Dr. Niren Murthy, and Dr. Suzanne Shuker (Committee Members).

Subjects/Keywords: Allyl sulfone; Aza-peptide; Biosynthesis; Cysteine protease; Cysteine proteinases; Irreversible inhibitors; Protease inhibitors; Sulphones; Vinyl sulfone

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

APA (6th Edition):

Gotz, M. G. (2004). Design, synthesis, and evaluation of irreversible peptidyl inhibitors for clan CA and clan CD cysteine proteases. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/8072

Chicago Manual of Style (16th Edition):

Gotz, Marion Gabriele. “Design, synthesis, and evaluation of irreversible peptidyl inhibitors for clan CA and clan CD cysteine proteases.” 2004. Doctoral Dissertation, Georgia Tech. Accessed January 17, 2021. http://hdl.handle.net/1853/8072.

MLA Handbook (7th Edition):

Gotz, Marion Gabriele. “Design, synthesis, and evaluation of irreversible peptidyl inhibitors for clan CA and clan CD cysteine proteases.” 2004. Web. 17 Jan 2021.

Vancouver:

Gotz MG. Design, synthesis, and evaluation of irreversible peptidyl inhibitors for clan CA and clan CD cysteine proteases. [Internet] [Doctoral dissertation]. Georgia Tech; 2004. [cited 2021 Jan 17]. Available from: http://hdl.handle.net/1853/8072.

Council of Science Editors:

Gotz MG. Design, synthesis, and evaluation of irreversible peptidyl inhibitors for clan CA and clan CD cysteine proteases. [Doctoral Dissertation]. Georgia Tech; 2004. Available from: http://hdl.handle.net/1853/8072

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