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You searched for +publisher:"Georgia Tech" +contributor:("Sheldon May"). 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 November 27, 2020. 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. 27 Nov 2020.

Vancouver:

Wu D. Discovery and characterization of a signaling molecule regulating somatic embryogenesis in loblolly pine. [Internet] [Doctoral dissertation]. Georgia Tech; 2008. [cited 2020 Nov 27]. 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

2. Shaffer, Hally A. Engineering the pregnane X receptor and estrogen receptor alpha to bind novel small molecules using negative chemical complementation.

Degree: PhD, Chemistry and Biochemistry, 2011, Georgia Tech

Nuclear receptors are ligand-activated transcription factors that play significant roles in various biological processes within the body, such as cell development, hormone metabolism, reproduction, and cardiac function. As transcription factors, nuclear receptors are involved in many diseases, such as diabetes, cancer, and arthritis, resulting in approximately 10-15% of the pharmaceutical drugs presently on the market being targeted toward nuclear receptors. Structurally, nuclear receptors consist of a DNA-binding domain (DBD), responsible for binding specific sequences of DNA called response elements, fused to a ligand-binding domain (LBD) through a hinge region. The LBD binds a small molecule ligand. Upon ligand binding, the LBD changes to an active conformation leading to the recruitment of coactivator (CoAC) proteins and initiation of transcription. As a result of their involvement in disease, there is an emphasis on engineering nuclear receptors for applications in gene therapy, drug discovery and metabolic engineering. Advisors/Committee Members: Bahareh Azizi (Committee Chair), Donald Doyle (Committee Chair), Andreas Bommarius (Committee Co-Chair), Loren Williams (Committee Co-Chair), Adegboyega Oyelere (Committee Member), Nick Hud (Committee Member), Sheldon May (Committee Member).

Subjects/Keywords: Nuclear receptors; Chemical complementation; Negative chemical complementation; Yeast-two hybrid selection; Pregnane X receptor; Estrogen receptor; Pregnane; Protein engineering; Nuclear receptors (Biochemistry); Transcription factors; Yeast Genetics

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

APA (6th Edition):

Shaffer, H. A. (2011). Engineering the pregnane X receptor and estrogen receptor alpha to bind novel small molecules using negative chemical complementation. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/39620

Chicago Manual of Style (16th Edition):

Shaffer, Hally A. “Engineering the pregnane X receptor and estrogen receptor alpha to bind novel small molecules using negative chemical complementation.” 2011. Doctoral Dissertation, Georgia Tech. Accessed November 27, 2020. http://hdl.handle.net/1853/39620.

MLA Handbook (7th Edition):

Shaffer, Hally A. “Engineering the pregnane X receptor and estrogen receptor alpha to bind novel small molecules using negative chemical complementation.” 2011. Web. 27 Nov 2020.

Vancouver:

Shaffer HA. Engineering the pregnane X receptor and estrogen receptor alpha to bind novel small molecules using negative chemical complementation. [Internet] [Doctoral dissertation]. Georgia Tech; 2011. [cited 2020 Nov 27]. Available from: http://hdl.handle.net/1853/39620.

Council of Science Editors:

Shaffer HA. Engineering the pregnane X receptor and estrogen receptor alpha to bind novel small molecules using negative chemical complementation. [Doctoral Dissertation]. Georgia Tech; 2011. Available from: http://hdl.handle.net/1853/39620


Georgia Tech

3. DeSilva, Veronica. Selenium redox cycling; isolation and characterization of a stimulatory component from tissue of loblolly pine for multiplication of somatic embryos; development of an assay to measure l-phenylalanine concentration in blood plasma.

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

Exogenously supplied organoselenium compounds, capable of propagating a selenium redox cycle, were shown to supplement natural cellular defenses against oxidants generated during biological activity. Phenylaminoalkyl selenides were developed in our laboratory as novel substrate analogs for the enzyme dopamine beta-monooxygenase. Recently, phenylaminoalkyl selenides were found to protect plasmid DNA and Molecular beacons from oxoperoxynitrate – mediated damage by scavenging this oxidant and forming the corresponding selenoxides as the sole selenium – containing products. Rate constants were determined for the reactions of the phenylaminoalkyl selenoxides with GSH at physiological pH and 25 degrees C. The kinetic data obtained in current and previous research was subsequently used in a MatLab simulation, which showed the feasibility of selenium redox cycling by GSH in the presence of a cellular oxidant, oxoperoxynitrate. Loblolly pine (LP, Pinus taeda) is the primary commercial species in southern forests covering 11.7 million hectares. Somatic embryogenesis (SE) is an effective technique to implement production of high value genotypes of LP. SE is a multi-step process, which includes initiation of somatic embryo (SME) growth from tree tissue, maintenance and multiplication of early stage SMEs and the maturation / germination phase. In this work, we isolated a substance from stage 2 or 3 LP female gametophyte (FG) tissue that stimulates early stage SME growth, and characterized this substance as citric acid on the basis of 1H NMR and mass spectrometry. We then demonstrated that topical application of citric acid to SMEs stimulates embryo colony growth at p = 0.05 for 3 of the 5 genotypes tested. Phenylketonuria (PKU) is an autosomal recessive disorder caused by an impaired conversion of L-phenylalanine (L-Phe) to L-tyrosine (L-Tyr). A novel assay based on enzymatic - colorimetric methodology (ECA) was developed in order to detect elevated concentrations of L-Phe in undeproteinized plasma of PKU patients via continuous spectrophotometric detection. We report here that L-Phe concentrations in undeproteinized plasma measured using our ECA were comparable to those determined on an amino acid analyzer based on Pearson correlation coefficients and a Bland and Altman comparison. Advisors/Committee Members: Sheldon May (Committee Chair), Nicholas Hud, Stanley Pollock, James Powers, and Gerald Pullman (Committee Members).

Subjects/Keywords: Phenylalanine dehydrogenase; PMS; MTS; Phenylketonuria; Enzymatic colorimetric assay; Citric acid; Loblolly pine; Somatic embryogenesis; GSH; Recycling; Molecular beacon; Phenylaminoalkyl selenides; Plasma amino acid analysis; HPLC; Tandem mass spectrometry; Peroxynitrite; Oxoperoxynitrate; Phenylaminoalkylselenoxides; Comparison; L-phenylalanine; Selenium; Oxidation-reduction reaction; Loblolly pine; Somatic embryogenesis; Phenylalanine; Blood plasma

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

APA (6th Edition):

DeSilva, V. (2007). Selenium redox cycling; isolation and characterization of a stimulatory component from tissue of loblolly pine for multiplication of somatic embryos; development of an assay to measure l-phenylalanine concentration in blood plasma. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/29788

Chicago Manual of Style (16th Edition):

DeSilva, Veronica. “Selenium redox cycling; isolation and characterization of a stimulatory component from tissue of loblolly pine for multiplication of somatic embryos; development of an assay to measure l-phenylalanine concentration in blood plasma.” 2007. Doctoral Dissertation, Georgia Tech. Accessed November 27, 2020. http://hdl.handle.net/1853/29788.

MLA Handbook (7th Edition):

DeSilva, Veronica. “Selenium redox cycling; isolation and characterization of a stimulatory component from tissue of loblolly pine for multiplication of somatic embryos; development of an assay to measure l-phenylalanine concentration in blood plasma.” 2007. Web. 27 Nov 2020.

Vancouver:

DeSilva V. Selenium redox cycling; isolation and characterization of a stimulatory component from tissue of loblolly pine for multiplication of somatic embryos; development of an assay to measure l-phenylalanine concentration in blood plasma. [Internet] [Doctoral dissertation]. Georgia Tech; 2007. [cited 2020 Nov 27]. Available from: http://hdl.handle.net/1853/29788.

Council of Science Editors:

DeSilva V. Selenium redox cycling; isolation and characterization of a stimulatory component from tissue of loblolly pine for multiplication of somatic embryos; development of an assay to measure l-phenylalanine concentration in blood plasma. [Doctoral Dissertation]. Georgia Tech; 2007. Available from: http://hdl.handle.net/1853/29788

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