You searched for +publisher:"Georgia Tech" +contributor:("Bommarius, Andreas").
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1.
Brittain, Alex David.
Mechanocatalytic depolymerization of lignin.
Degree: MS, Chemical and Biomolecular Engineering, 2016, Georgia Tech
URL: http://hdl.handle.net/1853/58208 
► In this work, mechanochemical reactions were performed to depolymerize organosolv lignin with sodium hydroxide in a mixer ball mill at ambient conditions. GPC analysis revealed…
(more)
▼ In this work, mechanochemical reactions were performed to depolymerize organosolv lignin with sodium hydroxide in a mixer ball mill at ambient conditions. GPC analysis revealed rapid depolymerization into small oligomers occurred within minutes of milling time, followed by a slower reduction in average relative molecular weight over the next eight hours of milling. Additionally, monomeric products were identified and quantified by GC-MS. The extent of depolymerization appeared to be limited by condensation reactions that form bonds between products. Suppression of these condensation reactions could be achieved through the addition of methanol as a scavenger or adjustment of the moisture content of the feedstock. These modifications resulted in lower average relative molecular weights and higher monomeric yields. The second portion of this work focuses on the mechanocatalytic depolymerization of lignin under ambient conditions using a variety of solid acid and base catalysts. The use of solid catalysts provides an easier separation from reaction products than sodium hydroxide, which will result in cost savings in industrial applications. Of the catalysts tested, only Mg(OH)2 proved to catalyze significant depolymerization, as determined by a decrease in relative average molecular weight measured by GPC, and creation of substantial yields of monomers as measured by GC-MS. Depolymerization with Mg(OH)2 was not as effective as sodium hydroxide catalyzed depolymerization, with smaller reductions in molecular weight and lower production of monomers for similar milling times. However, Mg(OH)2 was able to be easily completely recovered after the reaction through filtration, which was not possible with sodium hydroxide. The final section of this work involved the construction of a modified milling reactor to facilitate mechanocatalytic hydrogenation reactions at ambient conditions. Reactions of lignin model compound diphenyl ether using a Pt/Al2O3 catalyst revealed conversion to dicyclohexyl ether, cyclohexanol, and cyclohexanone. GC-MS quantification of products showed that reactivity was low for the first hour of milling, followed by a large increase in conversion at two hours of milling. This was followed by a slower increase in conversion between two and eight hours of milling. The volatile products of this reaction were carried out of the reactor by the effluent hydrogen stream and collected in a condenser downstream. The reactor designed for this work can be envisioned to provide an environment in which to simultaneously perform lignin depolymerization and hydrogenation reactions, creating a one-pot system for the creation and separation of fuel precursors.
Advisors/Committee Members: Sievers, Carsten (advisor), Bommarius, Andreas (advisor), Meredith, Carson (advisor).
Subjects/Keywords: Mechanocatalysis; Mechanochemistry; Lignin; Biomass; Ball mill
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APA (6th Edition):
Brittain, A. D. (2016). Mechanocatalytic depolymerization of lignin. (Masters Thesis). Georgia Tech. Retrieved from http://hdl.handle.net/1853/58208
Chicago Manual of Style (16th Edition):
Brittain, Alex David. “Mechanocatalytic depolymerization of lignin.” 2016. Masters Thesis, Georgia Tech. Accessed January 22, 2021.
http://hdl.handle.net/1853/58208.
MLA Handbook (7th Edition):
Brittain, Alex David. “Mechanocatalytic depolymerization of lignin.” 2016. Web. 22 Jan 2021.
Vancouver:
Brittain AD. Mechanocatalytic depolymerization of lignin. [Internet] [Masters thesis]. Georgia Tech; 2016. [cited 2021 Jan 22].
Available from: http://hdl.handle.net/1853/58208.
Council of Science Editors:
Brittain AD. Mechanocatalytic depolymerization of lignin. [Masters Thesis]. Georgia Tech; 2016. Available from: http://hdl.handle.net/1853/58208
Georgia Tech
2.
Perez Cuevas, Monica Beatriz.
Hepatitis B vaccination using a dissolvable microneedle patch.
Degree: MS, Chemical and Biomolecular Engineering, 2017, Georgia Tech
URL: http://hdl.handle.net/1853/59807
► Despite improved vaccination rates against hepatitis B, there remain critical barriers to addressing gaps in vaccination coverage. The need of an effective supply chain, vaccine…
(more)
▼ Despite improved vaccination rates against hepatitis B, there remain critical barriers to addressing gaps in vaccination coverage. The need of an effective supply chain, vaccine waste management, trained healthcare providers and cost are all issues that impede mass vaccination campaigns around the world. Microneedle patches have been proposed as an alternative mode of vaccination. Microneedle patches consist of micron-scale projections that are capable of disrupting the stratum corneum by creating holes in the skin to deliver therapeutic agents. Small and lightweight, microneedle patches are a promising alternative to the bulky multi-dose vials and syringes currently used in mass vaccination campaigns. Furthermore, the high density of antigen presenting cells in the the skin make transcutaneous immunization via microneedles advantageous, as they target vaccine cargo to the topmost layer of the skin. The key goal of this project was to develop a microneedle patch for hepatitis B vaccination that is simple to administer and of comparable immunogenicity to conventional intramuscular vaccination. Trehalose was used as a stabilizing excipient for both coated metal and dissolvable microneedles. Moreover, patches were used in vivo to compare the elicited immune response in both mice and rhesus macaques. Additionally, the mechanical properties of our microneedle patch were evaluated via both theoretical and experimental approaches to predict failure force. This work shows that microneedle patches can successfully encapsulate and deliver hepatitis B antigen to generate a strong and sustained immune response in multiple animal models.
Advisors/Committee Members: Prausnitz, Mark R. (advisor), Garcia, Andres J. (committee member), Bommarius, Andreas S. (committee member).
Subjects/Keywords: Microneedles; Hepatitis b
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APA (6th Edition):
Perez Cuevas, M. B. (2017). Hepatitis B vaccination using a dissolvable microneedle patch. (Masters Thesis). Georgia Tech. Retrieved from http://hdl.handle.net/1853/59807
Chicago Manual of Style (16th Edition):
Perez Cuevas, Monica Beatriz. “Hepatitis B vaccination using a dissolvable microneedle patch.” 2017. Masters Thesis, Georgia Tech. Accessed January 22, 2021.
http://hdl.handle.net/1853/59807.
MLA Handbook (7th Edition):
Perez Cuevas, Monica Beatriz. “Hepatitis B vaccination using a dissolvable microneedle patch.” 2017. Web. 22 Jan 2021.
Vancouver:
Perez Cuevas MB. Hepatitis B vaccination using a dissolvable microneedle patch. [Internet] [Masters thesis]. Georgia Tech; 2017. [cited 2021 Jan 22].
Available from: http://hdl.handle.net/1853/59807.
Council of Science Editors:
Perez Cuevas MB. Hepatitis B vaccination using a dissolvable microneedle patch. [Masters Thesis]. Georgia Tech; 2017. Available from: http://hdl.handle.net/1853/59807
Georgia Tech
3.
Sarria, Stephen.
Microbial synthesis of terpene and fatty acid biofuel precursors.
Degree: PhD, Chemistry and Biochemistry, 2018, Georgia Tech
URL: http://hdl.handle.net/1853/61119
► Our dependence on petroleum-derived fuels has accelerated the need for renewable fuel production. Microbial engineering is a promising avenue for production of advanced biofuels that…
(more)
▼ Our dependence on petroleum-derived fuels has accelerated the need for renewable fuel production. Microbial engineering is a promising avenue for production of advanced biofuels that can be dropped into existing transportation infrastructure. In this thesis, Escherichia coli was engineered to produce the terpene pinene, which is a precursor to a biosynthetic tactical fuel. The combinatorial approach of screening and fusing pinene-producing enzymes in E. coli improved pinene titers to 32 mg/L. This work also led to the discovery that pinene isomer ratios depend not only on the pinene synthase, but also the geraniol diphosphate synthase. In a similar light, medium-chain chemicals (MCCs) are also used as precursors to biofuels in addition to specialty chemicals. The engineering strategies, applications, and challenges surrounding the microbial production of MCCs are also explored in this thesis. To date, MCCs have generally been produced in mg/L levels; yet engineering of MCC precursor and tailoring enzymes can help improve microbial MCC titers to reach g/L levels. Medium-chain fatty acids (MCFAs) are key intermediates for MCCs but have low natural availability, which hinders their microbial production. In this thesis, E. coli MCFA production was improved over 3-fold by engineering the Acinetobacter baylyi medium-chain specific thioesterase (TE) for an improved interface with the E. coli acyl carrier protein. Finally, a phylogenetic-guided approach was used to engineer the A. baylyi TE for improved E. coli MCFA titers. The best phylogenetic-derived mutants improved MCFAs 1.3-fold with one mutant shifting the profile toward long-chain fatty acids. In conclusion, this work encompassed a combination of pathway and enzyme engineering to develop microbial strains capable of producing biofuel precursors. The accomplishments in this thesis work contribute engineered strains and improved enzymes to scientific community and sets essential groundwork for developing industrially relevant strains in the future.
Advisors/Committee Members: Kubanek, Julia (advisor), Lieberman, Raquel (committee member), Bommarius, Andreas (committee member), Wu, Ronghu (committee member).
Subjects/Keywords: Biofuels; Microbial engineering; Synthetic biology; Enzyme engineering
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APA (6th Edition):
Sarria, S. (2018). Microbial synthesis of terpene and fatty acid biofuel precursors. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/61119
Chicago Manual of Style (16th Edition):
Sarria, Stephen. “Microbial synthesis of terpene and fatty acid biofuel precursors.” 2018. Doctoral Dissertation, Georgia Tech. Accessed January 22, 2021.
http://hdl.handle.net/1853/61119.
MLA Handbook (7th Edition):
Sarria, Stephen. “Microbial synthesis of terpene and fatty acid biofuel precursors.” 2018. Web. 22 Jan 2021.
Vancouver:
Sarria S. Microbial synthesis of terpene and fatty acid biofuel precursors. [Internet] [Doctoral dissertation]. Georgia Tech; 2018. [cited 2021 Jan 22].
Available from: http://hdl.handle.net/1853/61119.
Council of Science Editors:
Sarria S. Microbial synthesis of terpene and fatty acid biofuel precursors. [Doctoral Dissertation]. Georgia Tech; 2018. Available from: http://hdl.handle.net/1853/61119
Georgia Tech
4.
Kwok, Thomas Tai-min.
Process engineering for lignin value prior to pulping.
Degree: PhD, Chemical and Biomolecular Engineering, 2019, Georgia Tech
URL: http://hdl.handle.net/1853/62663
► Biomass pretreatment unlocks chemical moieties for downstream valorization. This thesis focuses on organic solvent pretreatments that complement pulp production by delivering an additional lignin stream…
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▼ Biomass pretreatment unlocks chemical moieties for downstream valorization. This thesis focuses on organic solvent pretreatments that complement pulp production by delivering an additional lignin stream for the production of renewable chemicals. This work proposes and assesses a next-generation pulping process named Lignin Value Prior to Pulping (LVPP). Tools are developed to measure treatment efficacy, rank solvents for LVPP, and describe the process of retrofitting a pulp mill. This thesis presents Direct Yellow 11 as a replacement for Direct Orange 15 to measure cellulose accessibility, compare organic solvents, and enhance a cellulose conversion rate model. Additional screens and metrics are established to compare organic solvents within a solvent selection guide for LVPP. A set of solvents are evaluated using performance, hazard, exposure, cost, and process economic metrics. From this selection guide, 1,6 hexamethylenediamine, diethanolamine, propylene glycol, and 1-methyl piperazine are recommended for additional process development. A complete process design is presented for an LVPP treatment with 1,6 hexamethylenediamine, and a techno-economic analysis yields a minimum lignin selling price of $0.829/kg for economic viability. By incorporating an integrated computational and experimental technique, this thesis presents process and cost models that highlight feasibility constraints and technological barriers to future LVPP processes. This thesis aids the diversification of the pulp and paper industry towards new products, and it pushes the field towards favorable economics for renewable chemicals.
Advisors/Committee Members: Bommarius, Andreas S. (advisor), Realff, Matthew J. (advisor), Luettgen, Christopher O. (committee member), Peralta-Yahya, Pamela P. (committee member), Sievers, Carsten (committee member).
Subjects/Keywords: Lignocellulosic biomass; Techno-economics; Lignin value prior to pulping; Solvent selection; Delignification; Pretreatment; Pulping; Organosolv
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APA (6th Edition):
Kwok, T. T. (2019). Process engineering for lignin value prior to pulping. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/62663
Chicago Manual of Style (16th Edition):
Kwok, Thomas Tai-min. “Process engineering for lignin value prior to pulping.” 2019. Doctoral Dissertation, Georgia Tech. Accessed January 22, 2021.
http://hdl.handle.net/1853/62663.
MLA Handbook (7th Edition):
Kwok, Thomas Tai-min. “Process engineering for lignin value prior to pulping.” 2019. Web. 22 Jan 2021.
Vancouver:
Kwok TT. Process engineering for lignin value prior to pulping. [Internet] [Doctoral dissertation]. Georgia Tech; 2019. [cited 2021 Jan 22].
Available from: http://hdl.handle.net/1853/62663.
Council of Science Editors:
Kwok TT. Process engineering for lignin value prior to pulping. [Doctoral Dissertation]. Georgia Tech; 2019. Available from: http://hdl.handle.net/1853/62663
Georgia Tech
5.
Hudson, Benjamin Cole.
Solid-state NMR structural characterization of self-assembling peptide analogues.
Degree: PhD, Chemical and Biomolecular Engineering, 2018, Georgia Tech
URL: http://hdl.handle.net/1853/62215
► Research in the field of designer nanostructure has shown great potential for use of peptides, peptide analogues, and a wide array of small molecules in…
(more)
▼ Research in the field of designer nanostructure has shown great potential for use of peptides, peptide analogues, and a wide array of small molecules in a variety of industries and applications. As the field continues to expand, the need for techniques which are capable of providing structural detail at atomic-level resolution will only grow. The question of how best to extract atomic-level structural detail from these systems has yet to be adequately addressed, however. Here I show the efficacy of solid-state nuclear magnetic resonance (NMR) in extracting molecular-level detail from two self-assembling peptide analogues: peptoid B28 and fluorenylmethoxycarbonyl-diphenylalanine (Fmoc-FF). A study of peptoid B28 nanosheets has shown the capability of dipolar recoupling solid-state NMR to distinguish between the cis and trans configurations of peptoid backbone amide bonds, providing refined physical constraints for an evolving B28 nanosheet molecular model and revealing previously unconsidered peptoid backbone folding behavior. My study of Fmoc-FF suggests this system is highly polymorphic despite its small size, and that the polymorphism appears to be dependent on solvent environment. Despite this polymorphism however, two-dimensional solid-state NMR indicates each of our Fmoc-FF systems feature a common backbone hydrogen-bonding pattern of diphenylalanine sidechains inconsistent with the most widely accepted Fmoc-FF nanofiber model.
Solid-state NMR has never been applied either peptoid B28 or Fmoc-FF, nor is there any evidence in the literature that it has ever been applied a peptoid system or Fmoc-dipeptide. I am borrowing these solid-state NMR experiments from peptide characterization methods and applying them to probe for structural phenomena that has never been tested in either system. I have simply looked at the proposed molecular arrangements in both peptoid B28 and Fmoc-FF and applied measurements sensitive to the details I want to see. This is a not a standard application of solid-state NMR, but nothing new ever began as standard.
Advisors/Committee Members: Paravastu, Anant K. (advisor), Champion, Julie (committee member), Bommarius, Andreas (committee member), Grover, Martha (committee member), Lieberman, Raquel (committee member).
Subjects/Keywords: Solid-state NMR; Peptide analogue; Peptoid nanosheet; Low molecular weight gelator
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APA (6th Edition):
Hudson, B. C. (2018). Solid-state NMR structural characterization of self-assembling peptide analogues. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/62215
Chicago Manual of Style (16th Edition):
Hudson, Benjamin Cole. “Solid-state NMR structural characterization of self-assembling peptide analogues.” 2018. Doctoral Dissertation, Georgia Tech. Accessed January 22, 2021.
http://hdl.handle.net/1853/62215.
MLA Handbook (7th Edition):
Hudson, Benjamin Cole. “Solid-state NMR structural characterization of self-assembling peptide analogues.” 2018. Web. 22 Jan 2021.
Vancouver:
Hudson BC. Solid-state NMR structural characterization of self-assembling peptide analogues. [Internet] [Doctoral dissertation]. Georgia Tech; 2018. [cited 2021 Jan 22].
Available from: http://hdl.handle.net/1853/62215.
Council of Science Editors:
Hudson BC. Solid-state NMR structural characterization of self-assembling peptide analogues. [Doctoral Dissertation]. Georgia Tech; 2018. Available from: http://hdl.handle.net/1853/62215
Georgia Tech
6.
Bruce, Kathryn Lyn.
Roles of protein sequence and cell environment in cross-species prion transmission and amyloid interference.
Degree: PhD, Biology, 2014, Georgia Tech
URL: http://hdl.handle.net/1853/52288
► Proteinaceous infectious particles, termed 'prions' are self-perpetuating protein isoforms that transmit neurodegenerative diseases in mammals and phenotypic traits in yeast. Each conformational variant of a…
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▼ Proteinaceous infectious particles, termed 'prions' are self-perpetuating protein isoforms that transmit neurodegenerative diseases in mammals and phenotypic traits in yeast. Each conformational variant of a prion protein is faithfully propagated to a homologous protein in the same cell environment. However, a reduction in the efficiency of prion transmission between different species is often observed and is termed "species barrier". Prion transmission to a heterologous protein may, in some cases, permanently change the structure of the prion variant, and divergent proteins may interfere with prion propagation in a species-specific manner. To identify the importance of both protein sequence and the cell environment on prion interference and cross-species transmission, we employed heterologous Sup35 proteins from three Saccharomyces sensu stricto species: Saccharomyces cerevisiae (Sc), Saccharomyces paradoxus (Sp), and Saccharomyces bayanus (Sb). We performed our experiments in two different cell environments (Sc and Sp). Our data show that Sup35 from one species can form a prion in another, and we employed a transfection procedure to perform cross-species transfer of the prion. Using a shuffle procedure, we demonstrate that the specificity of prion transmission is determined by the protein itself rather than the cell environment. Interestingly, we noted that variant-specific prion patterns can be altered irreversibly during cross-species transmission through S. bayanus module II. We further show that prion interference does not always correlate with cross-species prion transmission, and the identity of particular regions or even a specific amino acid, rather than the overall level of PrD homology is crucial for determining cross-species transmission and interference. Lastly we provide evidence to suggest that prion interference is specific to the cell environment.
Advisors/Committee Members: Chernoff, Yury O. (advisor), Lobachev, Kirill S. (committee member), Storici, Francesca (committee member), Bommarius, Andreas S. (committee member), Gleason, Michael L. (committee member).
Subjects/Keywords: Prion; Amyloid; Prion interference; Saccharomyces; Species barrier; Sup35
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APA (6th Edition):
Bruce, K. L. (2014). Roles of protein sequence and cell environment in cross-species prion transmission and amyloid interference. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/52288
Chicago Manual of Style (16th Edition):
Bruce, Kathryn Lyn. “Roles of protein sequence and cell environment in cross-species prion transmission and amyloid interference.” 2014. Doctoral Dissertation, Georgia Tech. Accessed January 22, 2021.
http://hdl.handle.net/1853/52288.
MLA Handbook (7th Edition):
Bruce, Kathryn Lyn. “Roles of protein sequence and cell environment in cross-species prion transmission and amyloid interference.” 2014. Web. 22 Jan 2021.
Vancouver:
Bruce KL. Roles of protein sequence and cell environment in cross-species prion transmission and amyloid interference. [Internet] [Doctoral dissertation]. Georgia Tech; 2014. [cited 2021 Jan 22].
Available from: http://hdl.handle.net/1853/52288.
Council of Science Editors:
Bruce KL. Roles of protein sequence and cell environment in cross-species prion transmission and amyloid interference. [Doctoral Dissertation]. Georgia Tech; 2014. Available from: http://hdl.handle.net/1853/52288
Georgia Tech
7.
Al-Hmoud, Linda.
Understanding heterogeneous copper catalysts for coupling reactions in organic synthesis.
Degree: PhD, Chemical and Biomolecular Engineering, 2014, Georgia Tech
URL: http://hdl.handle.net/1853/52997
► Copper is an inexpensive, earth-abundant, non-toxic metal that is found to have widespread applications in catalysis. Ullmann and Ullmann-type reactions and Glaser-Hay oxidative coupling of…
(more)
▼ Copper is an inexpensive, earth-abundant, non-toxic metal that is found to have widespread applications in catalysis. Ullmann and Ullmann-type reactions and Glaser-Hay oxidative coupling of terminal alkynes are some of the well-established copper catalyzed coupling reactions used for the construction of important organic molecules, including pharmaceuticals, commodity chemicals and polymers. Those reactions have been mainly performed homogeneously, where the removal of residual copper from the reaction mixture is a challenge. Therefore, many researchers tried supporting copper precatalysts in order to help recover, and thus reduce final product contamination. Some studies showed that copper leached significantly from the support, with others showing that leached copper has a role in the catalysis. Nevertheless, many studies reported that the used supported catalysts were recyclable and claimed catalyst's heterogeneity. In most cases, the nature of the truly active copper species is still not clear.
The objectives of this thesis were (1) to assess the heterogeneity/homogeneity of active copper species in popular catalytic C-N coupling reactions with already studied catalysts, mainly a copper exchanged zeolite and copper oxide nanoparticles, and (2) to use the collected information in designing a truly heterogeneous (stable and recyclable) catalyst.
Initially, and because of its shape selectivity characteristics, copper-exchanged NaY zeolite, Cu(II)Y, was chosen to study the heterogeneity of copper catalyzed amination of aryl iodide with imidazole. The collected results from conducted shape selectivity tests indicated that Cu(II)Y might be heterogeneous catalyst, but because of the used base, that is crucial for this C-N coupling reaction, the crystallinity of the zeolite structure was diminished. Therefore, it was important to support copper on a framework that is stable under the basic conditions required for this type of reaction if a heterogeneous, recyclable catalyst were to be achieved. For this purpose, cerium oxide was chosen, and copper oxide supported on cerium oxide, CuO-CeOâ‚‚, was investigated as a potential heterogeneous catalyst for C-N coupling reaction. This investigation included the role of each reaction reagent in facilitating copper leaching into solution. It was found that copper leached from the support and it was demonstrated through hot filtration tests that the leached copper species was the main active catalyst. Leaching was caused by the solvent (DMSO) as well as the used reactants and the base. Similar conclusions were drawn when this CuO-CeOâ‚‚ catalyst was used for the direct synthesis of imines from amines under aerobic conditions. Although this CuO-CeOâ‚‚ catalyst has the advantages of being more recoverable and active than unsupported CuO nanoparticles at similar copper loadings, it is not fully recyclable, as the copper catalysis occurs in solution.
These findings meant that designing a truly heterogeneous catalyst for this reaction is a challenging task. Understanding the effect of each…
Advisors/Committee Members: Jones, Christopher W. (advisor), Zhang, Z. John (committee member), Soper, Jake (committee member), Agrawal, Pradeep K. (committee member), Bommarius, Andreas S. (committee member).
Subjects/Keywords: Copper catalysis; Heterogeneous catalysis; Organic synthesis
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APA ·
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APA (6th Edition):
Al-Hmoud, L. (2014). Understanding heterogeneous copper catalysts for coupling reactions in organic synthesis. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/52997
Chicago Manual of Style (16th Edition):
Al-Hmoud, Linda. “Understanding heterogeneous copper catalysts for coupling reactions in organic synthesis.” 2014. Doctoral Dissertation, Georgia Tech. Accessed January 22, 2021.
http://hdl.handle.net/1853/52997.
MLA Handbook (7th Edition):
Al-Hmoud, Linda. “Understanding heterogeneous copper catalysts for coupling reactions in organic synthesis.” 2014. Web. 22 Jan 2021.
Vancouver:
Al-Hmoud L. Understanding heterogeneous copper catalysts for coupling reactions in organic synthesis. [Internet] [Doctoral dissertation]. Georgia Tech; 2014. [cited 2021 Jan 22].
Available from: http://hdl.handle.net/1853/52997.
Council of Science Editors:
Al-Hmoud L. Understanding heterogeneous copper catalysts for coupling reactions in organic synthesis. [Doctoral Dissertation]. Georgia Tech; 2014. Available from: http://hdl.handle.net/1853/52997
Georgia Tech
8.
Yanto, Yanto.
Evaluation of novel enoate reductases as potential biocatalyst for enantiomerically pure compound synthesis.
Degree: PhD, Chemical Engineering, 2011, Georgia Tech
URL: http://hdl.handle.net/1853/39576
► Asymmetric synthesis with biocatalyst has become an increasingly interesting and cost effective manufacturing process in fine chemicals, pharmaceuticals, and agrochemical intermediates. Enoate reductases from the…
(more)
▼ Asymmetric synthesis with biocatalyst has become an increasingly interesting and cost effective manufacturing process in fine chemicals, pharmaceuticals, and agrochemical intermediates. Enoate reductases from the Old Yellow Enzyme family offer high substrate efficiency, region, stereo-, and enantioselectivity in the catalyzed biotransformations. Asymmetric reduction of activated C=C bond is one of the most widely applied synthetic tools for the potential to generate up to two stereogenic centers in one step reaction. The thesis contributed to the development and characterization of the Old Yellow Enzyme family members including NRSal from Salmonella typhimurium, YersER from Yersinia bercoviei, KYE1 from Kluyveromyces lactis, and XenA from Pseudomonas putida. We explored the possible new chemistry, gathered further understanding of enzymes functionality and biochemistry, evaluated parameters such as enzyme stability, productivity, and selectivity, and improved enzyme specificity through computational guided protein engineering method. In overall, the increasing knowledge about this Old Yellow Enzyme family together with recent advances in biotechnology renders the enoate reductases a tool of choice for industrial applications.
Advisors/Committee Members: Bommarius, Andreas (Committee Chair), Edmondson, Dale (Committee Member), Jones, Christopher (Committee Member), Prausnitz, Mark (Committee Member), Spain, Jim (Committee Member).
Subjects/Keywords: Biocatalyst; Enoate Reductases; Asymmetric Reduction; Biotechnology; Enzymes; Chiral drugs Synthesis; Alkenes; Reduction (Chemistry); Oxidoreductases
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APA (6th Edition):
Yanto, Y. (2011). Evaluation of novel enoate reductases as potential biocatalyst for enantiomerically pure compound synthesis. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/39576
Chicago Manual of Style (16th Edition):
Yanto, Yanto. “Evaluation of novel enoate reductases as potential biocatalyst for enantiomerically pure compound synthesis.” 2011. Doctoral Dissertation, Georgia Tech. Accessed January 22, 2021.
http://hdl.handle.net/1853/39576.
MLA Handbook (7th Edition):
Yanto, Yanto. “Evaluation of novel enoate reductases as potential biocatalyst for enantiomerically pure compound synthesis.” 2011. Web. 22 Jan 2021.
Vancouver:
Yanto Y. Evaluation of novel enoate reductases as potential biocatalyst for enantiomerically pure compound synthesis. [Internet] [Doctoral dissertation]. Georgia Tech; 2011. [cited 2021 Jan 22].
Available from: http://hdl.handle.net/1853/39576.
Council of Science Editors:
Yanto Y. Evaluation of novel enoate reductases as potential biocatalyst for enantiomerically pure compound synthesis. [Doctoral Dissertation]. Georgia Tech; 2011. Available from: http://hdl.handle.net/1853/39576
Georgia Tech
9.
Mistilis, Matthew Joseph.
Thermostabilization of influenza vaccine in microneedle patches.
Degree: PhD, Chemical and Biomolecular Engineering, 2016, Georgia Tech
URL: http://hdl.handle.net/1853/58153
► Vaccine delivery to the skin via microneedles confers several advantages over the traditional hypodermic needle and syringe. This work focuses on developing microneedles as a…
(more)
▼ Vaccine delivery to the skin via microneedles confers several advantages over the traditional hypodermic needle and syringe. This work focuses on developing microneedles as a thermostable delivery method for the influenza vaccine that can be completely removed from the cold-chain, thus minimizing cost and wastage during storage and transportation. Microneedle formulations were screened for their effect on influenza vaccine activity during drying. A number of excipients, particularly the combination of arginine and heptagluconate, successfully stabilized influenza vaccine during storage in the dried state and in microneedle patches at ambient or elevated temperatures for up to eighteen months. Influenza vaccine microneedle patches were shown to be resistant against several stresses and remained immunogenic in a mouse model after long-term storage. The primary mechanism of influenza vaccine activity loss during drying was aggregation, which can be mitigated by stabilizing excipients.
Advisors/Committee Members: Prausnitz, Mark R. (advisor), Bommarius, Andreas S. (advisor), Champion, Julie A. (committee member), Compans, Richard W. (committee member), Lieberman, Raquel L. (committee member).
Subjects/Keywords: Vaccine delivery; Vaccine stability; Microneedles; Drug delivery; Formulations; Dermal delivery
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APA (6th Edition):
Mistilis, M. J. (2016). Thermostabilization of influenza vaccine in microneedle patches. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/58153
Chicago Manual of Style (16th Edition):
Mistilis, Matthew Joseph. “Thermostabilization of influenza vaccine in microneedle patches.” 2016. Doctoral Dissertation, Georgia Tech. Accessed January 22, 2021.
http://hdl.handle.net/1853/58153.
MLA Handbook (7th Edition):
Mistilis, Matthew Joseph. “Thermostabilization of influenza vaccine in microneedle patches.” 2016. Web. 22 Jan 2021.
Vancouver:
Mistilis MJ. Thermostabilization of influenza vaccine in microneedle patches. [Internet] [Doctoral dissertation]. Georgia Tech; 2016. [cited 2021 Jan 22].
Available from: http://hdl.handle.net/1853/58153.
Council of Science Editors:
Mistilis MJ. Thermostabilization of influenza vaccine in microneedle patches. [Doctoral Dissertation]. Georgia Tech; 2016. Available from: http://hdl.handle.net/1853/58153
Georgia Tech
10.
Au, Samantha Kaling.
Development of amine dehydrogenases toward production of chiral amines.
Degree: PhD, Chemical and Biomolecular Engineering, 2016, Georgia Tech
URL: http://hdl.handle.net/1853/58172
► One in four of the top 200 selling pharmaceutical drugs contain a chiral amine. Chiral amines often require difficult synthesis through traditional heterogeneous catalysts. As…
(more)
▼ One in four of the top 200 selling pharmaceutical drugs contain a chiral amine. Chiral amines often require difficult synthesis through traditional heterogeneous catalysts. As a result, the use of biocatalysts in industrial applications to create amines has been increasingly desired and developed. Amine dehydrogenases (AmDHs) are a novel class of enzymes that catalyze the reaction of prochiral ketones to chiral amines. Through protein engineering on existing amino acid dehydrogenase scaffolds, ketones instead of carboxylic acids are now substrates of the AmDH. This work will describe the use of biocatalysts, specifically the AmDHs, as a green alternative to catalyze ketones to enantiomerically pure amines.
Advisors/Committee Members: Bommarius, Andreas S. (advisor), Styczynski, Mark (committee member), Champion, Julie (committee member), Peralta-Yahya, Pamela (committee member), Abrahamson, Michael J. (committee member).
Subjects/Keywords: Chiral amines; Dehydrogenases; Biocatalysts
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APA (6th Edition):
Au, S. K. (2016). Development of amine dehydrogenases toward production of chiral amines. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/58172
Chicago Manual of Style (16th Edition):
Au, Samantha Kaling. “Development of amine dehydrogenases toward production of chiral amines.” 2016. Doctoral Dissertation, Georgia Tech. Accessed January 22, 2021.
http://hdl.handle.net/1853/58172.
MLA Handbook (7th Edition):
Au, Samantha Kaling. “Development of amine dehydrogenases toward production of chiral amines.” 2016. Web. 22 Jan 2021.
Vancouver:
Au SK. Development of amine dehydrogenases toward production of chiral amines. [Internet] [Doctoral dissertation]. Georgia Tech; 2016. [cited 2021 Jan 22].
Available from: http://hdl.handle.net/1853/58172.
Council of Science Editors:
Au SK. Development of amine dehydrogenases toward production of chiral amines. [Doctoral Dissertation]. Georgia Tech; 2016. Available from: http://hdl.handle.net/1853/58172
Georgia Tech
11.
Raji, Idris.
Novel approaches towards the discovery of tumor-selective histone deacetylase inhibitors.
Degree: PhD, Chemistry and Biochemistry, 2016, Georgia Tech
URL: http://hdl.handle.net/1853/59152
► Developing safer and/ or more effective chemotherapeutics has been a long-standing challenge in the drug discovery field. To address these shortcomings, the designed-multiple ligand (DML)…
(more)
▼ Developing safer and/ or more effective chemotherapeutics has been a long-standing challenge in the drug discovery field. To address these shortcomings, the designed-multiple ligand (DML) and targeted approaches were used to design novel series of histone deacetylase inhibitors (HDACi). Under the DML approach, bifunctional compounds capable of binding to both histone deacetylase and cyclooxygenase enzymes were made. A subset of the bifunctional compounds was significantly less toxic towards healthy cells compared to the US Food Drug and Administration (FDA) approved HDACi, vorinostat, despite their impressive anticancer profiles. On the other hand, the targeted approach was conceptualized to address the lack of efficacy in solid tumors seen with clinically approved HDACi. Two different series of compounds are reported herein as potential interventions in lung cancer and melanoma. In one of the series, clarithromycin- known for its preferential accumulation in lung tissues, was incorporated into the structures of HDACi to generate clarithromycin-targeted HDACi. With the eventual goal of achieving compounds that will preferentially localize in lung cancer tissues, the clarithromycin-targeted HDACi showed very good anticancer profiles in in vitro studies. The second series of compounds generated using the targeted approach are aimed as potential intervention in melanoma. In this approach, a template, known as benzamide, with high affinity for melanin, was incorporated into the design of HDACi. The benzamide compounds obtained showed some promise in melanoma cell lines, and warrant further studies to optimize for potency.
Advisors/Committee Members: Oyelere, Adegboyega K. (advisor), Finn, M. G. (committee member), France, Stefan (committee member), Bommarius, Andreas (committee member), Bellamkonda, Ravi (committee member).
Subjects/Keywords: Histone deacetylase; HDACi; Cyclooxygenase; Macrolide; Clarithromycin; Melanoma; Designed-multiple ligand; Lung cancer; Prostate cancer; Liposome; PGE2; NF-kB; Celecoxib; Indomethacin; Benzamides; Androgen receptor
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APA (6th Edition):
Raji, I. (2016). Novel approaches towards the discovery of tumor-selective histone deacetylase inhibitors. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/59152
Chicago Manual of Style (16th Edition):
Raji, Idris. “Novel approaches towards the discovery of tumor-selective histone deacetylase inhibitors.” 2016. Doctoral Dissertation, Georgia Tech. Accessed January 22, 2021.
http://hdl.handle.net/1853/59152.
MLA Handbook (7th Edition):
Raji, Idris. “Novel approaches towards the discovery of tumor-selective histone deacetylase inhibitors.” 2016. Web. 22 Jan 2021.
Vancouver:
Raji I. Novel approaches towards the discovery of tumor-selective histone deacetylase inhibitors. [Internet] [Doctoral dissertation]. Georgia Tech; 2016. [cited 2021 Jan 22].
Available from: http://hdl.handle.net/1853/59152.
Council of Science Editors:
Raji I. Novel approaches towards the discovery of tumor-selective histone deacetylase inhibitors. [Doctoral Dissertation]. Georgia Tech; 2016. Available from: http://hdl.handle.net/1853/59152
Georgia Tech
12.
Faraji Mosalman, Mozhdeh Sadat.
From experimental observations to a functional model of the lignin pathway: Computational modeling reveals new insights.
Degree: PhD, Mechanical Engineering, 2018, Georgia Tech
URL: http://hdl.handle.net/1853/59881
► Lignin is a natural polymer that is interwoven with cellulose and hemicellulose within plant cell walls. Due to this molecular arrangement, lignin is a major…
(more)
▼ Lignin is a natural polymer that is interwoven with cellulose and hemicellulose within plant cell walls. Due to this molecular arrangement, lignin is a major
contributor to the recalcitrance of plant materials with respect to the extraction of sugars and their fermentation into ethanol, butanol, and other potential bioenergy crops. The lignin biosynthetic pathway is similar, but not identical in different plant species. It is in each case comprised of a moderate number of enzymatic steps, but its responses to manipulations, such as gene knock-downs, are complicated by the fact that several of the key enzymes are involved in several reaction steps. This feature poses a challenge to bioenergy production, as it renders it difficult to select the most promising combinations of genetic manipulations for the optimization of lignin composition and amount. Moreover, species specific regulatory features and distinct spatial and topological characteristics hinder accuracy of a unified lignin pathway model. In this dissertation a systems biology approach is used to address these challenges by means of computational modeling. Novel mathematical techniques are employed on different types of experimental data in situ, and shed light on complexities of lignin biosynthesis pathway. The developed methods are nevertheless general enough to be used in a wide range of metabolic modeling applications.
Advisors/Committee Members: Voit, Eberhard O. (advisor), Bommarius, Andreas S. (committee member), Leamy, Michael J. (committee member), Peralta-Yahya, Pamela (committee member), Qiu, Peng (committee member).
Subjects/Keywords: Lignin; Computational modeling
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APA (6th Edition):
Faraji Mosalman, M. S. (2018). From experimental observations to a functional model of the lignin pathway: Computational modeling reveals new insights. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/59881
Chicago Manual of Style (16th Edition):
Faraji Mosalman, Mozhdeh Sadat. “From experimental observations to a functional model of the lignin pathway: Computational modeling reveals new insights.” 2018. Doctoral Dissertation, Georgia Tech. Accessed January 22, 2021.
http://hdl.handle.net/1853/59881.
MLA Handbook (7th Edition):
Faraji Mosalman, Mozhdeh Sadat. “From experimental observations to a functional model of the lignin pathway: Computational modeling reveals new insights.” 2018. Web. 22 Jan 2021.
Vancouver:
Faraji Mosalman MS. From experimental observations to a functional model of the lignin pathway: Computational modeling reveals new insights. [Internet] [Doctoral dissertation]. Georgia Tech; 2018. [cited 2021 Jan 22].
Available from: http://hdl.handle.net/1853/59881.
Council of Science Editors:
Faraji Mosalman MS. From experimental observations to a functional model of the lignin pathway: Computational modeling reveals new insights. [Doctoral Dissertation]. Georgia Tech; 2018. Available from: http://hdl.handle.net/1853/59881
Georgia Tech
13.
Vermeersch, Kathleen A.
Systems-level characterization of ovarian cancer metabolism.
Degree: PhD, Chemical and Biomolecular Engineering, 2014, Georgia Tech
URL: http://hdl.handle.net/1853/54258
► The purpose of this thesis was to characterize cancer metabolism in vitro using epithelial ovarian cancer as a model on an untargeted, systems-level, basis with…
(more)
▼ The purpose of this thesis was to characterize cancer metabolism in vitro using epithelial ovarian cancer as a model on an untargeted, systems-level, basis with particular attention paid to the difference between cancer stem cell metabolism and cancer cell metabolism. Two-dimensional gas chromatography coupled to mass spectrometry was used to measure the metabolite profiles of the ovarian cancer and cancer stem cell lines under normal baseline conditions and also under chemotherapeutic and environmental perturbations. These two cell lines exhibited significant metabolic differences under normal baseline conditions and results demonstrated that metabolism in the ovarian cancer stem cell line was distinct from that of more differentiated isogenic cancer cells, showing similarities to stem cell metabolism that suggest the potential importance of metabolism for the cancer stem cell phenotype. Glucose deprivation, hypoxia, and ischemia all perturbed ovarian cancer and cancer stem cell metabolism, but not in the same ways between the cell types. Chemotherapeutic treatment with docetaxel caused metabolic changes mostly in amino acid and carbohydrate metabolism in ovarian cancer cells, while ovarian cancer stem cell metabolism was not affected by docetaxel. Overall, these metabolic differences between the two cell types will deepen our understanding of the metabolic changes occurring within the in vivo tumor and will help drive development of cancer stem cell targeted therapeutics.
Advisors/Committee Members: Styczynski, Mark P. (advisor), Chen, Rachel (committee member), Bommarius, Andreas S. (committee member), Dawson, Michelle R. (committee member), McDonald, John F. (committee member).
Subjects/Keywords: Cancer stem cells; Cancer metabolism; Ovarian cancer; Metabolomics
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APA (6th Edition):
Vermeersch, K. A. (2014). Systems-level characterization of ovarian cancer metabolism. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/54258
Chicago Manual of Style (16th Edition):
Vermeersch, Kathleen A. “Systems-level characterization of ovarian cancer metabolism.” 2014. Doctoral Dissertation, Georgia Tech. Accessed January 22, 2021.
http://hdl.handle.net/1853/54258.
MLA Handbook (7th Edition):
Vermeersch, Kathleen A. “Systems-level characterization of ovarian cancer metabolism.” 2014. Web. 22 Jan 2021.
Vancouver:
Vermeersch KA. Systems-level characterization of ovarian cancer metabolism. [Internet] [Doctoral dissertation]. Georgia Tech; 2014. [cited 2021 Jan 22].
Available from: http://hdl.handle.net/1853/54258.
Council of Science Editors:
Vermeersch KA. Systems-level characterization of ovarian cancer metabolism. [Doctoral Dissertation]. Georgia Tech; 2014. Available from: http://hdl.handle.net/1853/54258
Georgia Tech
14.
Encarnacion-Gomez, Luis G.
Design and operation of enzymatic reactive crystallization: Applications in chiral purity and kinetically controlled synthesis.
Degree: PhD, Chemical and Biomolecular Engineering, 2015, Georgia Tech
URL: http://hdl.handle.net/1853/54322
► The work presented in this thesis is aimed to design efficient reactive crystallization operations that could potentially be implemented in the manufacture of enantiomerically pure…
(more)
▼ The work presented in this thesis is aimed to design efficient reactive crystallization operations that could potentially be implemented in the manufacture of enantiomerically pure compounds and β-lactam antibiotics. Multiple aspects of solution thermodynamics, reaction engineering and crystallization from complex solutions are involved and will be discussed in detail through the following chapters.
The first piece of this work utilizes reactive crystallization for the manufacture of enantiomerically pure amino acids. Chemo-enzymatic stereoiversion reactions are used to enrich saturated or supersaturated solutions to favor the selection of a desired enantiomer. L-Methionine and L-Phenylalanine were resolve successfully from racemic mixtures by cyclic stereoinversion. r D-amino acids were oxidized by D-amino acid oxidase (D-AAO) and the resulting ketoacid was subsequently reduced by ammonia borane producing a racemic-mixture After the necessary enantiomeric enrichment was reached, system conditions were changed to induce supersaturation and promote crystal formation. In each case crystals with chemical and enantiomeric purities greater than 99% wt. were recovered. experimental information about reaction and crystallization kinetics was used to developed models. Such models were used to design model-based optimizations in which the productivity of the operation was enhanced by selecting an optimal temperature profile.
The second example is a reactive crystallization towards the manufacture of β-lactam antibiotics. One of the major drawbacks of the utilization of enzymes towards the manufacture of β-lactam antibiotics is the fact that the same enzyme that catalyzes the synthesis of the antibiotic also catalyzes its hydrolysis and thus, its degradation. The reaction scheme is a kinetically controlled synthesis in which the desired product is an intermediate within the network. Hence, the focus of this work is to design an efficient reactive crystallization in which the product is crystallized before it is consumed by hydrolysis. In order to accomplish this goal we have study solution equilibria, reaction kinetics, and crystallization kinetics. Even though crystallization kinetics of ampicillin has been previously reported; the reported models are not applicable to a reactive crystallization scheme for a variety of reasons. In this work, we have developed a robust model that can be applied to multiple crystallization protocols that are consistent with the conditions at which the enzymatic reaction can be performed.
Finally, a reactive-crystallization scheme in which ampicillin was successfully recovered from solution was developed. In this work, crystal seeds were used to promote crystallization of the desired product from the complex media. The results indicated that is possible to perform the reaction and crystallization in parallel, and still recover crystals with high purity. This work is the first example in which ampicillin was produced and recovered with high purity in a single stage. Previous work on…
Advisors/Committee Members: Rousseau, Ronald W. (advisor), Bommarius, Andreas S. (committee member), Kawajiri, Yoshiaki (committee member), Realff, Matthew J. (committee member), Liotta, Charles (committee member).
Subjects/Keywords: Crystallization; Reactive-crystallization; Enantiomers; Antibiotics
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APA (6th Edition):
Encarnacion-Gomez, L. G. (2015). Design and operation of enzymatic reactive crystallization: Applications in chiral purity and kinetically controlled synthesis. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/54322
Chicago Manual of Style (16th Edition):
Encarnacion-Gomez, Luis G. “Design and operation of enzymatic reactive crystallization: Applications in chiral purity and kinetically controlled synthesis.” 2015. Doctoral Dissertation, Georgia Tech. Accessed January 22, 2021.
http://hdl.handle.net/1853/54322.
MLA Handbook (7th Edition):
Encarnacion-Gomez, Luis G. “Design and operation of enzymatic reactive crystallization: Applications in chiral purity and kinetically controlled synthesis.” 2015. Web. 22 Jan 2021.
Vancouver:
Encarnacion-Gomez LG. Design and operation of enzymatic reactive crystallization: Applications in chiral purity and kinetically controlled synthesis. [Internet] [Doctoral dissertation]. Georgia Tech; 2015. [cited 2021 Jan 22].
Available from: http://hdl.handle.net/1853/54322.
Council of Science Editors:
Encarnacion-Gomez LG. Design and operation of enzymatic reactive crystallization: Applications in chiral purity and kinetically controlled synthesis. [Doctoral Dissertation]. Georgia Tech; 2015. Available from: http://hdl.handle.net/1853/54322
Georgia Tech
15.
Kang, Yuzhi.
Biomass pretreatment toward efficient hydrolysis for sustainable biofuel applications.
Degree: PhD, Chemical and Biomolecular Engineering, 2015, Georgia Tech
URL: http://hdl.handle.net/1853/54852
► The production of biofuels from non-edible plant biomass has been necessitated by the concern for the environmental consequences of fossil fuel use and the tightening…
(more)
▼ The production of biofuels from non-edible plant biomass has been necessitated by the concern for the environmental consequences of fossil fuel use and the tightening of supply and demand for liquid fuels. In contrast to first generation biofuels which rely on crops used for food supplies, second generation biofuels, derived from lignin-containing feedstocks, completely eliminate the competition for food. The major challenges associated with second generation biofuels are both technical and economic. Due to the recalcitrant nature of the raw biomass materials to further biological conversion, their structural degradation often requires severe and costly pretreatment processes such as heat, physical and chemical treatments to disturb and fractionate the biomass. Significant research effort has been devoted to understanding the recalcitrant nature and to accelerate the commercialization process of second generation biofuels. In this thesis, three pretreatment methods that belong to different categories have been investigated to understand their impacts on cellulose and/or lignocellulose and the subsequent hydrolysis steps.
Physicochemical pretreatments, such as steam explosion, have been identified as one of the most effective and cost-efficient pretreatment methods for lignocelluosic materials. In Chapter 2, SO2-catalyzed steam explosion will be discussed and the effect of pretreatment severity on the substrate characteristics and degradation efficiency is also elucidated. Although the crystallinity index (CrI) of cellulose decreases as the severity increases, significant non-specific degradation and low yield of cellulose was observed at high severity. A new method for cellulose CrI determination has been developed with least squares curve fitting and validated with mechanically mixed cellulose samples. Biological pretreatment is another pathway through which the biomass structure can be modified to obtain a more amenable state for enzymatic degradation. Cellulose-binding domain (CBD) originated from Trichoderma reesei Cel7A (i.e. Tr cellobiohydrolase I) has been discovered as a potential biological pretreatment agent which is capable of modifying cellulose crystal structure. An extensive study on the protein engineering, expression, purification and functionalities of Cel7A CBDs was carried out (Chapter 3). The target mutations were identified with a computational protein engineering method involving principal component analysis (PCA). Due to the lack of catalytic activity and high throughput screening method, the library size was limited to nine. The wild-type and mutated CBDs were compared for their adsorption behavior and decrystallization effect on cellulose. Resulting saccharification efficiency after CBD pretreatment were studied and a possible explanation for the rate enhancement was proposed.
In addition to physicochemical and biological pretreatment methods, chemical pretreatment is also a commonly employed method to overcome the recalcitrance of lignocellulosic materials. The most widely studied…
Advisors/Committee Members: Bommarius, Andreas S. (advisor), Realff, Matthew J. (advisor), Lee, Jay H. (committee member), Peralta-Yahya, Pamela (committee member), Doran-Peterson, Joy (committee member).
Subjects/Keywords: Biofuels; Pretreatment
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APA (6th Edition):
Kang, Y. (2015). Biomass pretreatment toward efficient hydrolysis for sustainable biofuel applications. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/54852
Chicago Manual of Style (16th Edition):
Kang, Yuzhi. “Biomass pretreatment toward efficient hydrolysis for sustainable biofuel applications.” 2015. Doctoral Dissertation, Georgia Tech. Accessed January 22, 2021.
http://hdl.handle.net/1853/54852.
MLA Handbook (7th Edition):
Kang, Yuzhi. “Biomass pretreatment toward efficient hydrolysis for sustainable biofuel applications.” 2015. Web. 22 Jan 2021.
Vancouver:
Kang Y. Biomass pretreatment toward efficient hydrolysis for sustainable biofuel applications. [Internet] [Doctoral dissertation]. Georgia Tech; 2015. [cited 2021 Jan 22].
Available from: http://hdl.handle.net/1853/54852.
Council of Science Editors:
Kang Y. Biomass pretreatment toward efficient hydrolysis for sustainable biofuel applications. [Doctoral Dissertation]. Georgia Tech; 2015. Available from: http://hdl.handle.net/1853/54852
Georgia Tech
16.
Herrera Estrada, Lina Paola.
Production and Engineering of Therapeutic Protein Nanoparticles.
Degree: PhD, Chemical and Biomolecular Engineering, 2014, Georgia Tech
URL: http://hdl.handle.net/1853/56153
► Protein nanoparticles were proposed as therapeutic protein or enzyme delivery vehicles. The production of protein-enzyme nanoparticles via desolvation and self-assembly was investigated and optimized. First,…
(more)
▼ Protein nanoparticles were proposed as therapeutic protein or enzyme delivery vehicles. The production of protein-enzyme nanoparticles via desolvation and self-assembly was investigated and optimized. First, β-galactosidase –a model enzyme– was incorporated into enhanced green fluorescent protein (eGFP) nanoparticles prepared via desolvation. Particle size was shown to be sensitive to type of cross-linker, cross-linking time, and the presence of imidazole. Protein-enzyme nanoparticles are shown to effectively deliver active enzyme to multiple cell lines in vitro. Then the potential of protein nanoparticles for therapeutic protein and enzyme delivery was studied in two diseases models: inflammatory bowel disease (IBD) and breast cancer. Bacterial effector proteins, AvrA and YopJ, were proposed as potential therapeutic agents because of their ability to efficiently subvert the MAPK and NF-κB pathways, which have been implicated in the pathogenesis and progression of IBD and breast cancer. AvrA was incorporated into eGFP nanoparticles and the resulting particles were shown to effectively deliver the effector to target cells in vitro and in vivo, inhibit inflammatory signaling and decrease inflammation in murine colitis models. YopJ was fused to Glutathione-S-Transferase (GST), which caused self-assembly of the fusion into stable nanoparticles. These particles were shown to induce cell death in a panel of breast cancer cell lines, but were not cytotoxic to non-breast cancer cells. Furthermore, these particles decreased cell migration in vitro and performed better or as well as a chemotherapeutic agent, doxorubicin. This data suggests that protein nanoparticles are a biocompatible, high efficiency alternative for intracellular delivery of active enzyme therapeutics, and demonstrates the potential of effector proteins as therapeutic agents.
Advisors/Committee Members: Champion, Julie A (advisor), Kemp, Melissa (committee member), Bommarius, Andreas (committee member), Payne, Christine (committee member), Taite, Lakeisha (committee member).
Subjects/Keywords: Nanoparticles; Enzymes; Bacterial Protein Effectors; Desolvation; Self-assembly; IBD; Breast Cancer; YopJ; AvrA
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APA (6th Edition):
Herrera Estrada, L. P. (2014). Production and Engineering of Therapeutic Protein Nanoparticles. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/56153
Chicago Manual of Style (16th Edition):
Herrera Estrada, Lina Paola. “Production and Engineering of Therapeutic Protein Nanoparticles.” 2014. Doctoral Dissertation, Georgia Tech. Accessed January 22, 2021.
http://hdl.handle.net/1853/56153.
MLA Handbook (7th Edition):
Herrera Estrada, Lina Paola. “Production and Engineering of Therapeutic Protein Nanoparticles.” 2014. Web. 22 Jan 2021.
Vancouver:
Herrera Estrada LP. Production and Engineering of Therapeutic Protein Nanoparticles. [Internet] [Doctoral dissertation]. Georgia Tech; 2014. [cited 2021 Jan 22].
Available from: http://hdl.handle.net/1853/56153.
Council of Science Editors:
Herrera Estrada LP. Production and Engineering of Therapeutic Protein Nanoparticles. [Doctoral Dissertation]. Georgia Tech; 2014. Available from: http://hdl.handle.net/1853/56153
Georgia Tech
17.
Padmore, Trudy J.
Controlled release of GLP-1 from affinity-based protein microspheres and quantitative analysis of the role of fiber length on phagocytosis and inflammatory response by macrophages.
Degree: PhD, Chemical and Biomolecular Engineering, 2016, Georgia Tech
URL: http://hdl.handle.net/1853/56336
► Peptide drugs are highly specific and efficacious; interest in them remains high despite the challenges of rapid clearance and degradation. To overcome these limitations peptide…
(more)
▼ Peptide drugs are highly specific and efficacious; interest in them remains high despite the challenges of rapid clearance and degradation. To overcome these limitations peptide delivery systems must prolong release while protecting biological activity. Glucagon-like peptide 1 (GLP-1) stimulates insulin secretion from pancreatic β-cells and is used for treatment of type 2 diabetes. However, GLP-1 undergoes rapid deactivation by proteolytic degradation and its size leads to a short, 2-minute half-life. An affinity-mediated delivery system can prolong half-life, while modification of its amino acid sequence can confer protease resistance. Here we describe a strategy to prolong the release of active Glucagon-like peptide 1 (GLP-1) using Src homology 3 (SH3) domain protein microparticles that bind GLP-1 through affinity-mediated interactions. GLP-1 modified with SH3-binding peptides of weak and strong affinities (GLP-1-SBPs) facilitate tunable release from SH3 microparticles. Release rates of GLP-1 from SH3 microspheres were strongly dependent on the SH3 binding peptide affinity, with the weaker binding GLP-1-SBP13 releasing 40% of its total cargo and the stronger binding GLP-1-SBP2 releasing 20% over a 7-day period. Released GLP-1 stimulated significant increases in Beta cell number, while insulin secretion stimulation was not significant in comparison to basal untreated level. Mathematical models qualitatively replicated affinity-dependent release trends. Quantitative analysis of the role of fiber length on phagocytosis and inflammatory response by macrophages. Asbestos fibers induce chronic lung inflammation and have been associated (WHO estimate) with 105 lung cancer deaths per year worldwide. In the lung, immune cells (macrophages) attempt to engulf inhaled foreign materials (like asbestos), secreting inflammatory molecules. The inability of macrophages to effectively remove asbestos leads to chronic inflammation and disease. Although the health effects of asbestos have been extensively investigated, this study examines the role of fiber length on phagocytosis and molecular inflammatory responses so as to characterize fiber toxicity at the cellular level. A major challenge is obtaining fibers of the same diameter, d, but differing in length, L. Glass fibers, with d ~1micron, were used as a model for asbestos. Samples with different measured length distributions were prepared: aggressive crushing for short fibers populations and successive sedimentation for long fibers populations. The interactions of MH-S murine alveolar macrophages with the fibers were analyzed by time-lapse video microscopy, to qualitatively describe attempted phagocytosis in real time, and by flow cytometry, to quantitatively measure attachment and internalization of fibers. Short fibers were observed to bind to macrophages, being internalized with little effort. Conversely, macrophages literally wrestled with long fibers over many hours, usually with unsuccessful internalization. Short fibers were twice as likely to be internalized as the long…
Advisors/Committee Members: Champion, Julie A. (advisor), Behrens, Sven (committee member), Bommarius, Andreas (committee member), GarcÃa, Andrés J. (committee member), McDevitt, Todd (committee member).
Subjects/Keywords: GLP-1; Controlled release; Affinity-based release; Protein microspheres; Fiber length; Length models
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APA (6th Edition):
Padmore, T. J. (2016). Controlled release of GLP-1 from affinity-based protein microspheres and quantitative analysis of the role of fiber length on phagocytosis and inflammatory response by macrophages. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/56336
Chicago Manual of Style (16th Edition):
Padmore, Trudy J. “Controlled release of GLP-1 from affinity-based protein microspheres and quantitative analysis of the role of fiber length on phagocytosis and inflammatory response by macrophages.” 2016. Doctoral Dissertation, Georgia Tech. Accessed January 22, 2021.
http://hdl.handle.net/1853/56336.
MLA Handbook (7th Edition):
Padmore, Trudy J. “Controlled release of GLP-1 from affinity-based protein microspheres and quantitative analysis of the role of fiber length on phagocytosis and inflammatory response by macrophages.” 2016. Web. 22 Jan 2021.
Vancouver:
Padmore TJ. Controlled release of GLP-1 from affinity-based protein microspheres and quantitative analysis of the role of fiber length on phagocytosis and inflammatory response by macrophages. [Internet] [Doctoral dissertation]. Georgia Tech; 2016. [cited 2021 Jan 22].
Available from: http://hdl.handle.net/1853/56336.
Council of Science Editors:
Padmore TJ. Controlled release of GLP-1 from affinity-based protein microspheres and quantitative analysis of the role of fiber length on phagocytosis and inflammatory response by macrophages. [Doctoral Dissertation]. Georgia Tech; 2016. Available from: http://hdl.handle.net/1853/56336
Georgia Tech
18.
Park, Won Min.
Self-assembly of protein-based suprastructures.
Degree: PhD, Chemical and Biomolecular Engineering, 2015, Georgia Tech
URL: http://hdl.handle.net/1853/58135
► Strategies for self-assembly of protein-based suprastructures were developed. Recombinant protein building blocks were designed, produced, and self-assembled into various suprastructures, which include spheres, vesicles, nanosheets…
(more)
▼ Strategies for self-assembly of protein-based suprastructures were developed. Recombinant protein building blocks were designed, produced, and self-assembled into various suprastructures, which include spheres, vesicles, nanosheets and porous particles. Morphology was manipulated by engineering protein building blocks, controlling self-assembly processes, and combining inorganic nanocrystals into hybrid materials. Self-assembly of spherical protein coacervates was achieved in the extracellular matrix, mediated by spontaneous diffusion-coacervation and high-affinity binding of building blocks. Vesicles and two-dimensional nanosheets were self-assembled from recombinant protein complexes, whose molecular geometry dictated the morphologies of self-assembled structures. Self-clustering hybrid flower-shaped nanoparticles were prepared and further assembled into hierarchically structured porous supraparticles. All the suprastructures were created as modular systems which enabled incorporation folded functional proteins. Enzymes incorporated in the porous supraparticles showed enhanced inactivation of a pro-inflammatory cytokine, tumor necrosis factor-α. The modular design approach, combined with manipulation of morphology, offer opportunities for practical applications.
Advisors/Committee Members: Champion, Julie A. (advisor), Babensee, Julia E. (committee member), Behrens, Sven H. (committee member), Bommarius, Andreas S. (committee member), Sambanis, Athanassios (committee member).
Subjects/Keywords: Protein; Self-assembly
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APA (6th Edition):
Park, W. M. (2015). Self-assembly of protein-based suprastructures. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/58135
Chicago Manual of Style (16th Edition):
Park, Won Min. “Self-assembly of protein-based suprastructures.” 2015. Doctoral Dissertation, Georgia Tech. Accessed January 22, 2021.
http://hdl.handle.net/1853/58135.
MLA Handbook (7th Edition):
Park, Won Min. “Self-assembly of protein-based suprastructures.” 2015. Web. 22 Jan 2021.
Vancouver:
Park WM. Self-assembly of protein-based suprastructures. [Internet] [Doctoral dissertation]. Georgia Tech; 2015. [cited 2021 Jan 22].
Available from: http://hdl.handle.net/1853/58135.
Council of Science Editors:
Park WM. Self-assembly of protein-based suprastructures. [Doctoral Dissertation]. Georgia Tech; 2015. Available from: http://hdl.handle.net/1853/58135
Georgia Tech
19.
Rose, Harrison B.
Towards an enzymatic route to 2,5-furandicarboxylic acid.
Degree: PhD, Chemical and Biomolecular Engineering, 2018, Georgia Tech
URL: http://hdl.handle.net/1853/61151
► This research project explored the selection and development of an enzymatic route from the renewable feedstocks furfural and carbon dioxide to 2,5-furandicarboxylic acid, a building…
(more)
▼ This research project explored the selection and development of an enzymatic route from the renewable feedstocks furfural and carbon dioxide to 2,5-furandicarboxylic acid, a building block for bio-based polyesters. A putative prenylated flavin-dependent reversible decarboxylase was identified as the most reasonable biocatalyst choice, although it was not isolated in a stable and active form in this work. To support future reaction engineering endeavors, this project also included studies of the aqueous liquid and solid solubility relationships between the reactive pathway intermediates and possible side products: furfural, 2 furancarboxylic acid, 5-formyl-2-furancarboxylic acid, and 2,5-furandicarboxylic acid. Finally, this work included an exploration into the mathematics of pH equilibria in aqueous reaction systems. These mathematical techniques were used to develop tools for assessing such systems by both colorimetric and calorimetric methods.
Advisors/Committee Members: Bommarius, Andreas S. (advisor), Realff, Matthew J. (committee member), Jones, Christopher W. (committee member), Finn, M. G. (committee member), Sadowski, Gabriele (committee member).
Subjects/Keywords: 2,5-furandicarboxylic acid; pH equilibria; Biocatalysis
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APA (6th Edition):
Rose, H. B. (2018). Towards an enzymatic route to 2,5-furandicarboxylic acid. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/61151
Chicago Manual of Style (16th Edition):
Rose, Harrison B. “Towards an enzymatic route to 2,5-furandicarboxylic acid.” 2018. Doctoral Dissertation, Georgia Tech. Accessed January 22, 2021.
http://hdl.handle.net/1853/61151.
MLA Handbook (7th Edition):
Rose, Harrison B. “Towards an enzymatic route to 2,5-furandicarboxylic acid.” 2018. Web. 22 Jan 2021.
Vancouver:
Rose HB. Towards an enzymatic route to 2,5-furandicarboxylic acid. [Internet] [Doctoral dissertation]. Georgia Tech; 2018. [cited 2021 Jan 22].
Available from: http://hdl.handle.net/1853/61151.
Council of Science Editors:
Rose HB. Towards an enzymatic route to 2,5-furandicarboxylic acid. [Doctoral Dissertation]. Georgia Tech; 2018. Available from: http://hdl.handle.net/1853/61151
Georgia Tech
20.
McNerney, Monica Pearl.
Biosensor development for field-deployable diagnostics.
Degree: PhD, Chemical and Biomolecular Engineering, 2019, Georgia Tech
URL: http://hdl.handle.net/1853/63490
► Almost all current tests for biomarkers require venous blood draws, extensive sample processing, and analysis with complex equipment. Inexpensive, easy-to-use tests are critical for expanding…
(more)
▼ Almost all current tests for biomarkers require venous blood draws, extensive sample processing, and analysis with complex equipment. Inexpensive, easy-to-use tests are critical for expanding healthcare to under-developed regions, but the requirement for reliable quantification in complex sample types (like blood) has been a critical roadblock in developing such diagnostics. Microbial-based biosensors have the potential to serve as a robust and generalizable platform for such diagnostics, as microbes can sense a wide variety of clinically relevant analytes and can produce colored outputs that are visible to the naked eye. Further, cell-free systems, which use bacterial protein extract to implement genetic networks, can be freeze-dried and rehydrated in the sample to be analyzed, enabling long-term storage at ambient temperatures and point-of-care test implementation and interpretation. This work describes the development of bacteria-based diagnostic assays that use bacterial sensing methods to control production of different colored readouts that are visible to the naked eye, yet quantitative and robust to the interference effects seen in complex samples. Using this platform, I develop a nearly field-deployable test for zinc deficiency (which is estimated to cause over 100,000 childhood deaths annually) that accurately measures clinically relevant zinc concentrations. The test requires just a finger-prick of blood, is robust to temperature variation, and can be freeze-dried for long term storage. I also use this approach to measure other classes of biomarkers, demonstrating a generalizable platform for low-cost quantitative diagnostics.
Advisors/Committee Members: Styczynski, Mark P (advisor), Hammer, Brian (committee member), Peralta-Yahya, Pamela (committee member), Bommarius, Andreas (committee member), Lu, Hang (committee member).
Subjects/Keywords: synthetic biology; biosensors; bioengineering
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APA (6th Edition):
McNerney, M. P. (2019). Biosensor development for field-deployable diagnostics. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/63490
Chicago Manual of Style (16th Edition):
McNerney, Monica Pearl. “Biosensor development for field-deployable diagnostics.” 2019. Doctoral Dissertation, Georgia Tech. Accessed January 22, 2021.
http://hdl.handle.net/1853/63490.
MLA Handbook (7th Edition):
McNerney, Monica Pearl. “Biosensor development for field-deployable diagnostics.” 2019. Web. 22 Jan 2021.
Vancouver:
McNerney MP. Biosensor development for field-deployable diagnostics. [Internet] [Doctoral dissertation]. Georgia Tech; 2019. [cited 2021 Jan 22].
Available from: http://hdl.handle.net/1853/63490.
Council of Science Editors:
McNerney MP. Biosensor development for field-deployable diagnostics. [Doctoral Dissertation]. Georgia Tech; 2019. Available from: http://hdl.handle.net/1853/63490
Georgia Tech
21.
Polizzi, Karen Marie.
Tools for Maximizing the Efficiency of Protein Engineering.
Degree: PhD, Chemical Engineering, 2005, Georgia Tech
URL: http://hdl.handle.net/1853/7511
► Biocatalysts offer advantages over their chemical counterparts in terms of their high enantioselectivity and the opportunity to develop more environmentally friendly processes. However, the widespread…
(more)
▼ Biocatalysts offer advantages over their chemical counterparts in terms of their high enantioselectivity and the opportunity to develop more environmentally friendly processes. However, the widespread adoption of biocatalytic processes is hampered by the long development times for enzymes with novel and sufficient activity and adequate stability under operating conditions. Protein engineering, while extremely useful for modifying the properties of protein catalysts in select cases, still cannot be performed rapidly enough for many applications. In order for biocatalysts to become a competitive alternative to chemical catalysts, new tools to make the tailoring of biocatalysts by protein engineering methods speedier and more efficient are necessary. The aim of this work was to develop methods to aid in the faster production of novel biocatalysts.
Protein engineering involves two steps: the generation of diversity and the screening or selection of variants with the desired properties. Both of these must be targeted to create a faster protein engineering process. In the case of the former, this work sought to clone and overexpress some template enzymes which would create smaller, more manageable libraries of mutants with a higher likelihood of function by the manipulation of a few focused amino acid residues. For the latter, this work developed and validated a Monte-Carlo simulation model of pooling to increase screening throughput and created a set of vectors to aid in high-throughput screening by eliminating unwanted mutants from the assay procedure entirely.
Advisors/Committee Members: Bommarius, Andreas (Committee Chair).
Subjects/Keywords: Pooling; Cloning vector; High-throughput screening; Protein engineering; Biocatalysis; Enzymes; Protein engineering; Biochemical engineering
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APA (6th Edition):
Polizzi, K. M. (2005). Tools for Maximizing the Efficiency of Protein Engineering. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/7511
Chicago Manual of Style (16th Edition):
Polizzi, Karen Marie. “Tools for Maximizing the Efficiency of Protein Engineering.” 2005. Doctoral Dissertation, Georgia Tech. Accessed January 22, 2021.
http://hdl.handle.net/1853/7511.
MLA Handbook (7th Edition):
Polizzi, Karen Marie. “Tools for Maximizing the Efficiency of Protein Engineering.” 2005. Web. 22 Jan 2021.
Vancouver:
Polizzi KM. Tools for Maximizing the Efficiency of Protein Engineering. [Internet] [Doctoral dissertation]. Georgia Tech; 2005. [cited 2021 Jan 22].
Available from: http://hdl.handle.net/1853/7511.
Council of Science Editors:
Polizzi KM. Tools for Maximizing the Efficiency of Protein Engineering. [Doctoral Dissertation]. Georgia Tech; 2005. Available from: http://hdl.handle.net/1853/7511
Georgia Tech
22.
Ichikawa, Hiroyuki.
Biosynthesis of the thiopetins and identification of an F420H2-dependent dehydropiperidine reductase.
Degree: PhD, Chemistry and Biochemistry, 2019, Georgia Tech
URL: http://hdl.handle.net/1853/62709
► Thiopeptins are highly decorated thiopeptide antibiotics similar in structure to thiostrepton A and harbor two unusual features. All thiopeptins contain a thioamide, a rare moiety…
(more)
▼ Thiopeptins are highly decorated thiopeptide antibiotics similar in structure to thiostrepton A and harbor two unusual features. All thiopeptins contain a thioamide, a rare moiety among natural products, and a subset of thiopeptins present with a piperidine in the core macrocycle rather than the more oxidated dehydropiperidine or pyridine rings typically observed in the thiopeptides. Here, we report the identification of the thiopeptin biosynthetic gene (tpn) cluster in Streptomyces tateyamensis and the gene products, TpnLMNW. TpnW shows sequence similarity to transaminases and is likely involved in the biosynthesis of the 4-(1-hydroxyethyl)quinoline-2-carboxylic acid (HEQ) moiety of thiopeptin. HEQ is derived from L-tryptophan and the second step of HEQ biosynthesis requires a transaminase that catalyzes the conversion of 2-methyl-L-tryptophan to 3-(2-methylindolyl)pyruvate. In vitro reconstitution of TpnW activity confirmed that this enzyme is a 2-methyl-L-tryptophan aminotransferase. TpnW is able to utilize 3 indolylpyruvate, p-hydroxyphenylpyruvate, and phenylpyruvate as α-keto acid acceptors but not pyruvate, oxaloacetate, or α-ketoglutarate. TpnMN share homology to YcaO and TfuA proteins, respectively, responsible for thioamidation of peptidic substrates. Heterologous expression of TpnMN in the thiostrepton A producer, Streptomyces laurentii (S. laurentii), led to the production of a metabolite with a mass matching a thioamidated thiostrepton A. Structural characterization of this metabolite is required to determine if it contains a thioamide suggested by the proposed functions of TpnMN. TpnL shows sequence similarity to (deaza)flavin-dependent oxidoreductases. Heterologous expression of TpnL in the thiostrepton A producer, S. laurentii, led to the production of a piperidine-containing analog. Binding studies revealed TpnL preferentially binds the deazaflavin cofactor, coenzyme F420, and in vitro reconstitution of TpnL activity confirmed that this enzyme is an F420H2-dependent dehydropiperidine reductase. The identification of TpnL and its activity establishes the basis for the piperidine-containing series a thiopeptides, one of the five main structural groups of this diverse family of antibiotics. This work was published in J. Am. Chem. Soc. in 2018.
Advisors/Committee Members: Kelly, Wendy L. (advisor), Bommarius, Andreas S. (committee member), Kubanek, Julia M. (committee member), Lobachev, Kirill S. (committee member), Oyelere, Adegboyega K. (committee member).
Subjects/Keywords: Biosynthesis thiopeptide
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APA (6th Edition):
Ichikawa, H. (2019). Biosynthesis of the thiopetins and identification of an F420H2-dependent dehydropiperidine reductase. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/62709
Chicago Manual of Style (16th Edition):
Ichikawa, Hiroyuki. “Biosynthesis of the thiopetins and identification of an F420H2-dependent dehydropiperidine reductase.” 2019. Doctoral Dissertation, Georgia Tech. Accessed January 22, 2021.
http://hdl.handle.net/1853/62709.
MLA Handbook (7th Edition):
Ichikawa, Hiroyuki. “Biosynthesis of the thiopetins and identification of an F420H2-dependent dehydropiperidine reductase.” 2019. Web. 22 Jan 2021.
Vancouver:
Ichikawa H. Biosynthesis of the thiopetins and identification of an F420H2-dependent dehydropiperidine reductase. [Internet] [Doctoral dissertation]. Georgia Tech; 2019. [cited 2021 Jan 22].
Available from: http://hdl.handle.net/1853/62709.
Council of Science Editors:
Ichikawa H. Biosynthesis of the thiopetins and identification of an F420H2-dependent dehydropiperidine reductase. [Doctoral Dissertation]. Georgia Tech; 2019. Available from: http://hdl.handle.net/1853/62709
Georgia Tech
23.
Edens, William Christopher.
Measles and polio vaccination using a microneedle patch to increase vaccination coverage in the developing world.
Degree: PhD, Biomedical Engineering (Joint GT/Emory Department), 2013, Georgia Tech
URL: http://hdl.handle.net/1853/52951
► Despite the existence of effective vaccines for both diseases, measles and poliomyelitis still cause significant worldwide morbidity and mortality. The live-attenuated measles and inactivated polio…
(more)
▼ Despite the existence of effective vaccines for both diseases, measles and poliomyelitis still cause significant worldwide morbidity and mortality. The live-attenuated measles and inactivated polio vaccines are both given using a standard needle and syringe injection. This method of delivery poses many problems for large-scale vaccination campaigns. Microneedles are micron-scale needles which have the potential to overcome many of these hurdles.
In the first study, we showed that the measles vaccine could be successfully incorporated into a solid, metal microneedle system which induced potent neutralizing antibody titers after administration into cotton rats. This response was statistically identical to the same dose delivered using a subcutaneous injection.
The second study focused on enhancing the stability of the measles vaccine after drying and long-term storage. Using a new assay developed from a measles virus variant engineered to encode for green fluorescent protein, it was determined that a combination of sucrose and threonine provided the highest stabilizing effect. Vaccine mixed with this solution retained more than 90% of its activity after 6 months of storage at 4°C and 25°C.
The third study involved the incorporation of the measles vaccine into a dissolving microneedle patch. These patches were used to vaccinate rhesus macaques and the immune response was found to be statistically identical to the same dose delivered by syringe injection. Furthermore, after creation and storage, these patches retained 100% of their infectivity after 2 months at 4°C and 25°C.
The final study attempted to create a dissolving microneedle patch containing a full dose of the inactivated polio vaccine. These patches were then used to deliver a full dose of IPV into the skin of a rhesus macaque. This delivery method produced neutralizing antibody titers to IPV type 1 and 2 that were statistically identical to the same dose delivered using a needle and syringe.
Overall, these studies show that the microneedle patch was a safe, simple and effective method for measles and polio vaccination. This delivery platform has the potential to overcome many of the hurdles that currently stand in the way of measles elimination and polio eradication.
Advisors/Committee Members: Prausnitz, Mark R. (advisor), Bommarius, Andreas S. (committee member), Dixon, J. Brandon (committee member), Kemp, Melissa L. (committee member), Rota, Paul A. (committee member).
Subjects/Keywords: Measles; Microneedle; Polio; Vaccination; Monkey; Skin; Vaccine stability
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APA (6th Edition):
Edens, W. C. (2013). Measles and polio vaccination using a microneedle patch to increase vaccination coverage in the developing world. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/52951
Chicago Manual of Style (16th Edition):
Edens, William Christopher. “Measles and polio vaccination using a microneedle patch to increase vaccination coverage in the developing world.” 2013. Doctoral Dissertation, Georgia Tech. Accessed January 22, 2021.
http://hdl.handle.net/1853/52951.
MLA Handbook (7th Edition):
Edens, William Christopher. “Measles and polio vaccination using a microneedle patch to increase vaccination coverage in the developing world.” 2013. Web. 22 Jan 2021.
Vancouver:
Edens WC. Measles and polio vaccination using a microneedle patch to increase vaccination coverage in the developing world. [Internet] [Doctoral dissertation]. Georgia Tech; 2013. [cited 2021 Jan 22].
Available from: http://hdl.handle.net/1853/52951.
Council of Science Editors:
Edens WC. Measles and polio vaccination using a microneedle patch to increase vaccination coverage in the developing world. [Doctoral Dissertation]. Georgia Tech; 2013. Available from: http://hdl.handle.net/1853/52951
Georgia Tech
24.
Sandridge, Matthew J.
Dehydrative cyclizations via acid catalysis as a method for molecular diversity.
Degree: PhD, Chemistry and Biochemistry, 2018, Georgia Tech
URL: http://hdl.handle.net/1853/59880
► Development of new synthetic methodologies that allow for efficient access to desirable core structures is a consistently valuable area of research for synthetic chemistry. Good…
(more)
▼ Development of new synthetic methodologies that allow for efficient access to desirable core structures is a consistently valuable area of research for synthetic chemistry. Good methodologies provide rapid access to systematically varying compounds with desirable properties, enabling functional testing and the discovery of new, useful compounds and materials. Three novel synthetic methodologies that make use of dehydrative cyclizations of carbinols via Lewis acid catalysis have been developed towards this end: (1) A calcium-catalyzed, dehydrative, ring-opening cyclization of cyclopropyl carbinols to form (hetero)aryl-fused cyclohexa-1,3-dienes; (2) A Bi(OTf)3-catalyzed synthesis of α-alkylidene-γ-butyrolactones from the ring-opening cyclization of cyclopropyl carbinols; (3) A calcium-catalyzed synthesis of cyclopenta[b]thiophenes and indenes via dehydrative Nazarov-type electrocyclizations of alkenyl (hetero)aryl carbinols. The mechanistic details of how each of these methods perform have also been investigated. Initial results and proposals for consequent projects, which span the breadth of target synthesis and new methodologies, have also been established.
Advisors/Committee Members: France, Stefan (advisor), Collard, David (committee member), Bommarius, Andreas (committee member), Finn, M. G. (committee member), Payne, Christine (committee member), Gutekunst, William (committee member).
Subjects/Keywords: Acid catalysis; Molecular diversity; Dehydrative cyclizations; Organic synthesis
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APA (6th Edition):
Sandridge, M. J. (2018). Dehydrative cyclizations via acid catalysis as a method for molecular diversity. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/59880
Chicago Manual of Style (16th Edition):
Sandridge, Matthew J. “Dehydrative cyclizations via acid catalysis as a method for molecular diversity.” 2018. Doctoral Dissertation, Georgia Tech. Accessed January 22, 2021.
http://hdl.handle.net/1853/59880.
MLA Handbook (7th Edition):
Sandridge, Matthew J. “Dehydrative cyclizations via acid catalysis as a method for molecular diversity.” 2018. Web. 22 Jan 2021.
Vancouver:
Sandridge MJ. Dehydrative cyclizations via acid catalysis as a method for molecular diversity. [Internet] [Doctoral dissertation]. Georgia Tech; 2018. [cited 2021 Jan 22].
Available from: http://hdl.handle.net/1853/59880.
Council of Science Editors:
Sandridge MJ. Dehydrative cyclizations via acid catalysis as a method for molecular diversity. [Doctoral Dissertation]. Georgia Tech; 2018. Available from: http://hdl.handle.net/1853/59880
Georgia Tech
25.
Agrawal, Gaurav.
Systematic optimization and experimental validation of simulated moving bed chromatography systems for ternary separations and equilibrium limited reactions.
Degree: PhD, Chemical and Biomolecular Engineering, 2014, Georgia Tech
URL: http://hdl.handle.net/1853/54028
► Simulated Moving Bed (SMB) chromatography is a separation process where the components are separated due to their varying affinity towards the stationary phase. Over the…
(more)
▼ Simulated Moving Bed (SMB) chromatography is a separation process where the components are separated due to their varying affinity towards the stationary phase. Over the past decade, many modifications have been proposed in SMB chromatography in order to effectively separate a binary mixture. However, the separation of multi-component mixtures using SMB is still one of the major challenges. Although many different strategies have been proposed, previous studies have rarely performed comprehensive investigations for finding the best ternary separation strategy from various possible alternatives. Furthermore, the concept of combining reaction with SMB has been proposed in the past for driving the equilibrium limited reactions to completion by separating the products from the reaction zone. However, the design of such systems is still challenging due to the complex dynamics of simultaneous reaction and adsorption.
The first objective of the study is to find the best ternary separation strategy among various alternatives design of SMB. The performance of several ternary SMB operating schemes, that are proposed in the literature, are compared in terms of the optimal productivity obtained and the amount of solvent consumed. A multi- objective optimization problem is formulated which maximizes the SMB productivity and purity of intermediate eluting component at the same time. Furthermore, the concept of optimizing a superstructure formulation is proposed, where numerous SMB operating schemes can be incorporated into a single formulation. This superstructure approach has a potential to find more advantageous operating scheme compared to existing operating schemes in the literature.
The second objective of the study is to demonstrate the Generalized Full Cycle (GFC) operation experimentally for the first time, and compare its performance to the JO process. A Semba OctaveTM chromatography system is used as an experimental SMB unit to implement the optimal operating schemes. In addition, a simultaneous optimization and model correction (SOMC) scheme is used to resolve the model mismatch in a systematic way. We also show a systematic comparison of both JO and GFC operations by presenting a Pareto plot of the productivity achieved against the desired purity of the intermediate eluting component experimentally.
The third objective of the study is to develop an simulated moving bed reactor (SMBR) process for an industrial-scale application, and demonstrate the potential of the ModiCon operation for improving the performance of the SMBR compared to the conventional operating strategy. A novel industrial application involving the esterification of acetic acid and 1-methoxy-2-propanol is considered to produce propylene glycol methyl ether (PMA) as the product. A multi-objective optimization study is presented to find the best reactive separation strategy for the production of the PMA product. We also present a Pareto plot that compares the ModiCon operation, which allows periodical change of the feed composition and the…
Advisors/Committee Members: Kawajiri, Yoshiaki (advisor), Realff, Matthew J. (committee member), Grover, Martha (committee member), Nenes, Athanasios (committee member), Bommarius, Andreas S. (committee member), Tsiotras, Panagiotis (committee member).
Subjects/Keywords: Simulated moving bed chromatography; Reactive separation; Parameter estimation; Modeling and optimization; Ternary separation
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APA (6th Edition):
Agrawal, G. (2014). Systematic optimization and experimental validation of simulated moving bed chromatography systems for ternary separations and equilibrium limited reactions. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/54028
Chicago Manual of Style (16th Edition):
Agrawal, Gaurav. “Systematic optimization and experimental validation of simulated moving bed chromatography systems for ternary separations and equilibrium limited reactions.” 2014. Doctoral Dissertation, Georgia Tech. Accessed January 22, 2021.
http://hdl.handle.net/1853/54028.
MLA Handbook (7th Edition):
Agrawal, Gaurav. “Systematic optimization and experimental validation of simulated moving bed chromatography systems for ternary separations and equilibrium limited reactions.” 2014. Web. 22 Jan 2021.
Vancouver:
Agrawal G. Systematic optimization and experimental validation of simulated moving bed chromatography systems for ternary separations and equilibrium limited reactions. [Internet] [Doctoral dissertation]. Georgia Tech; 2014. [cited 2021 Jan 22].
Available from: http://hdl.handle.net/1853/54028.
Council of Science Editors:
Agrawal G. Systematic optimization and experimental validation of simulated moving bed chromatography systems for ternary separations and equilibrium limited reactions. [Doctoral Dissertation]. Georgia Tech; 2014. Available from: http://hdl.handle.net/1853/54028
Georgia Tech
26.
Oh, Jung Min.
Development of reactive chromatography system for equilibrium-limited reactions.
Degree: PhD, Chemical and Biomolecular Engineering, 2016, Georgia Tech
URL: http://hdl.handle.net/1853/56333
► In the present work, an application of reactive chromatography and SMBR using ion exchange resin as a catalyst and adsorbent will be studied, which will…
(more)
▼ In the present work, an application of reactive chromatography and SMBR using ion exchange resin as a catalyst and adsorbent will be studied, which will be a new platform for production of industrial esters. Among numerous esters, this study focuses on the production of propylene glycol methyl ether acetate (DOWANOLTM PMA glycol ether acetate), one of the most commonly used esters with a high industrial demand. DOWANOLTM PMA glycol ether acetate is the second-most used propylene glycol ether with nearly 90% of its use in surface coatings.
Advisors/Committee Members: Kawajiri, Yoshiaki (committee member), Bommarius, Andreas S. (committee member), Koros, William J. (committee member), Walton, Krista S. (committee member), Donaldson, Megan E. (committee member).
Subjects/Keywords: Reactive chromatography; Esterification; Transesterification; Ion exchange resin
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APA (6th Edition):
Oh, J. M. (2016). Development of reactive chromatography system for equilibrium-limited reactions. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/56333
Chicago Manual of Style (16th Edition):
Oh, Jung Min. “Development of reactive chromatography system for equilibrium-limited reactions.” 2016. Doctoral Dissertation, Georgia Tech. Accessed January 22, 2021.
http://hdl.handle.net/1853/56333.
MLA Handbook (7th Edition):
Oh, Jung Min. “Development of reactive chromatography system for equilibrium-limited reactions.” 2016. Web. 22 Jan 2021.
Vancouver:
Oh JM. Development of reactive chromatography system for equilibrium-limited reactions. [Internet] [Doctoral dissertation]. Georgia Tech; 2016. [cited 2021 Jan 22].
Available from: http://hdl.handle.net/1853/56333.
Council of Science Editors:
Oh JM. Development of reactive chromatography system for equilibrium-limited reactions. [Doctoral Dissertation]. Georgia Tech; 2016. Available from: http://hdl.handle.net/1853/56333
27.
Smith, McKenzie L.
Systematic investigation of protein-metabolite regulatory interactions: methodologies and context.
Degree: PhD, Chemical and Biomolecular Engineering, 2016, Georgia Tech
URL: http://hdl.handle.net/1853/56353
► A systems-level understanding of metabolism will have far-reaching benefits from medicine to ecology to industry, as it will facilitate the comprehensive profiling and prediction of…
(more)
▼ A systems-level understanding of metabolism will have far-reaching benefits from medicine to ecology to industry, as it will facilitate the comprehensive profiling and prediction of metabolic states in organisms of interest. Systematic characterization strategies have thus far been successfully applied at the genomic, transcriptomic, and proteomic levels, but downstream regulatory interactions have remained comparatively underexplored. We believe this is largely due to the wide sensitivity spectrum required to effect a similarly comprehensive study: the binding affinities of known protein-metabolite regulatory pairs span multiple orders of magnitude. The overarching aim of this work was therefore to explore and develop multiple complementary strategies for discovery and characterization of these interactions. An in vitro reaction assay-based pipeline was developed to provide a flexible framework for both the validation of putative regulatory interactions found via other methods, and the discovery of new regulatory interactions over a wide range of binding affinities. Small-molecule microarrays were explored as a potential platform for high-throughput discovery of the stronger range of binding interactions, which work will provide a basis for future development and wide-range implementation of the assay. Additionally, a concurrent metabolomics study of inappetence in spawning salmon yielded insights into the metabolic profile of inappetent versus fed cohorts; these results also provide high-level context for protein- and pathway- level studies. Taken together, these findings provide a methodological framework to increase the efficiency and range of study for protein-metabolite regulatory interactions, as well as lay groundwork for further expansion of that range, ultimately in service of the future development of systems-level metabolic models.
Advisors/Committee Members: Styczynski, Mark P (advisor), Bommarius, Andreas S (committee member), Champion, Julie A (committee member), Fernandez, Facundo M (committee member), Kelly, Wendy L (committee member).
Subjects/Keywords: Allostery; Metabolomics; Systems biology
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APA ·
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APA (6th Edition):
Smith, M. L. (2016). Systematic investigation of protein-metabolite regulatory interactions: methodologies and context. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/56353
Chicago Manual of Style (16th Edition):
Smith, McKenzie L. “Systematic investigation of protein-metabolite regulatory interactions: methodologies and context.” 2016. Doctoral Dissertation, Georgia Tech. Accessed January 22, 2021.
http://hdl.handle.net/1853/56353.
MLA Handbook (7th Edition):
Smith, McKenzie L. “Systematic investigation of protein-metabolite regulatory interactions: methodologies and context.” 2016. Web. 22 Jan 2021.
Vancouver:
Smith ML. Systematic investigation of protein-metabolite regulatory interactions: methodologies and context. [Internet] [Doctoral dissertation]. Georgia Tech; 2016. [cited 2021 Jan 22].
Available from: http://hdl.handle.net/1853/56353.
Council of Science Editors:
Smith ML. Systematic investigation of protein-metabolite regulatory interactions: methodologies and context. [Doctoral Dissertation]. Georgia Tech; 2016. Available from: http://hdl.handle.net/1853/56353
28.
McClendon, Shara Demetria.
Molecular design, construction, and characterization of a xylanosome: a protein nanostructure for biomass utilization.
Degree: PhD, Chemical Engineering, 2011, Georgia Tech
URL: http://hdl.handle.net/1853/43610
► Lignocellulosic biomass is an abundant renewable resource targeted for biofuel production. Cellulose and hemicellulose from biomass both contain fermentable sugars and other moieties that can…
(more)
▼ Lignocellulosic biomass is an abundant renewable resource targeted for biofuel production. Cellulose and hemicellulose from biomass both contain fermentable sugars and other moieties that can be converted to biofuels or other commodity chemicals. Enzymatic hydrolysis of these biopolymers is a critical step in the liberation of sugars for fermentation into desired products. In nature, anaerobic microbes produce protein nanostructures called cellulosomes that efficiently degrade cellulose substrates by combining multiple enzyme activities onto a scaffolding protein. However, current enzyme cocktails used in industry contain secretomes of aerobic microbes and are not efficient enough to be highly economical. Furthermore, most bio-processes focus on cellulose, rendering hemicellulose under-utilized. The three main objectives of this dissertation are to 1) develop multi-functional, self-assembling protein nanostructures for hemicellulose degradation using the architecture provided by cellulosomes, 2) understand the self-assembly mechanism at conditions for consolidated bioprocessing applications, and 3) compare the effectiveness of structured to non-structured hemicellulases in the hydrolysis of biomass.
Xylan is a major type of hemicellulose in biomass feedstocks targeted for biofuel production. Six different xylanosomes were designed for hydrolysis of xylan within multiple biomass substrates using the cohesin-dockerin domain systems from Clostridium thermocellum, Clostridium cellulovorans, and Clostridium cellulolyticum. Each two-unit structure contained a xylanase for internal cleavage of the xylan backbone and one side-chain acting enzyme, either a ferulic acid esterase or bi-functional arabinofuranosidase/xylosidase. Expansion to three-unit xylanosomes included a family 10 or 11 xylanase, a bi-functional arabinofuranosidase/xylosidase, and bi-functional ferulic acid esterase/acetylxylan esterase. These multi-functional biocatalysts were used to degrade hemicellulose-rich wheat arabinoxylan and cellulose-containing destarched corn bran. Synergistic release of soluble sugars and ferulic acid was observed with select xylanosomes and in some cases required addition of an endoglucanase and cellobiohydrolase for enhanced hydrolysis. Furthermore, a putative ferulic acid esterase gene from the soil bacterium Cellvibrio japonicus was characterized and its role in xylan hydrolysis investigated.
Information for the development of stable and functional cellulosome-like biocatalysts in metabolically-engineered microbes was collected using surface plasmon resonance. The protein-protein interaction of cohesin and dockerin domains for xylanosome self-assembly was examined at various temperatures and in the presence of ethanol to mimic different hydrolysis and fermentation processes and found to retain high affinities at the selected conditions. Moreover, the high-affinity interaction of cohesin and dockerin domains in the presence of non-specific proteins eliminated the need for protein purification for…
Advisors/Committee Members: Chen, Rachel (Committee Chair), Bommarius, Andreas (Committee Member), Champion, Julie (Committee Member), May, Sheldon (Committee Member), Meredith, Carson (Committee Member).
Subjects/Keywords: Cellulosomes; Cohesin-dockerin interaction; Xylan hydroysis; Consolidated bioprocessing; Ferulic acid esterase; Cellulose Chemistry; Cellulose; Cellulose Biodegradation; Biomass; Renewable energy sources; Renewable natural resources
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APA ·
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APA (6th Edition):
McClendon, S. D. (2011). Molecular design, construction, and characterization of a xylanosome: a protein nanostructure for biomass utilization. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/43610
Chicago Manual of Style (16th Edition):
McClendon, Shara Demetria. “Molecular design, construction, and characterization of a xylanosome: a protein nanostructure for biomass utilization.” 2011. Doctoral Dissertation, Georgia Tech. Accessed January 22, 2021.
http://hdl.handle.net/1853/43610.
MLA Handbook (7th Edition):
McClendon, Shara Demetria. “Molecular design, construction, and characterization of a xylanosome: a protein nanostructure for biomass utilization.” 2011. Web. 22 Jan 2021.
Vancouver:
McClendon SD. Molecular design, construction, and characterization of a xylanosome: a protein nanostructure for biomass utilization. [Internet] [Doctoral dissertation]. Georgia Tech; 2011. [cited 2021 Jan 22].
Available from: http://hdl.handle.net/1853/43610.
Council of Science Editors:
McClendon SD. Molecular design, construction, and characterization of a xylanosome: a protein nanostructure for biomass utilization. [Doctoral Dissertation]. Georgia Tech; 2011. Available from: http://hdl.handle.net/1853/43610
29.
Clairmont, Ryan Michael.
Azolium ions: A versatile framework for chemistry on early earth.
Degree: PhD, Chemical and Biomolecular Engineering, 2016, Georgia Tech
URL: http://hdl.handle.net/1853/55021
► This work examines azolium catalysis of the small molecules formaldehyde and glyoxylic acid to yield product sugars as the starting point for synthesis of new…
(more)
▼ This work examines azolium catalysis of the small molecules formaldehyde and glyoxylic acid to yield product sugars as the starting point for synthesis of new azolium catalysts. It is broken into two projects: the first focusing on developing a proof of concept process to couple the two reactions, and the second expanding the reaction space using different solvents and catalyst. From these projects, a model for chemical evolution of small molecule catalysts was proposed. Reaction stoichiometry suggests that the process displays autocatalysis; however, the reactions were conducted separately so that kinetic enhancement was not observed. Even without kinetic enhancement, the findings indicate that synthesis of new catalyst from formaldehyde as the sole carbon source is possible, and that the process is robust due to effects such as catalyst deactivation or other loss pathways over time. Alternative work using glyoxylic acid demonstrated that the kinetics for carbohydrate synthesis are much slower.
Advisors/Committee Members: Bommarius, Andreas S. (advisor), Liotta, Charles L. (advisor), Schork, Francis J. (advisor), Grover, Martha (advisor), Weber, Arthur (advisor).
Subjects/Keywords: Azolium; Autocatalysis; Prebiotic
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APA (6th Edition):
Clairmont, R. M. (2016). Azolium ions: A versatile framework for chemistry on early earth. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/55021
Chicago Manual of Style (16th Edition):
Clairmont, Ryan Michael. “Azolium ions: A versatile framework for chemistry on early earth.” 2016. Doctoral Dissertation, Georgia Tech. Accessed January 22, 2021.
http://hdl.handle.net/1853/55021.
MLA Handbook (7th Edition):
Clairmont, Ryan Michael. “Azolium ions: A versatile framework for chemistry on early earth.” 2016. Web. 22 Jan 2021.
Vancouver:
Clairmont RM. Azolium ions: A versatile framework for chemistry on early earth. [Internet] [Doctoral dissertation]. Georgia Tech; 2016. [cited 2021 Jan 22].
Available from: http://hdl.handle.net/1853/55021.
Council of Science Editors:
Clairmont RM. Azolium ions: A versatile framework for chemistry on early earth. [Doctoral Dissertation]. Georgia Tech; 2016. Available from: http://hdl.handle.net/1853/55021
30.
Chen, Buxin.
Prion species barrier at the short phylogenetic distances in the yeast model.
Degree: PhD, Biology, 2008, Georgia Tech
URL: http://hdl.handle.net/1853/29762
► Prions are self-perpetuating and, in most cases, aggregation-prone protein isoforms that transmit neurodegenerative diseases in mammals and control heritable traits in yeast. Prion conversion requires…
(more)
▼ Prions are self-perpetuating and, in most cases, aggregation-prone protein isoforms that transmit neurodegenerative diseases in mammals and control heritable traits in yeast. Prion conversion requires a very high level of identity of the interacting protein sequences. Decreased transmission of the prion state between divergent proteins is termed "species barrier" and was thought to occur due to the inability of divergent prion proteins to co-aggregate. Species barrier can be overcome in cross-species infections, for example from "mad cows" to humans. We studied the counterparts of yeast prion protein Sup35, originated from three different species of the Saccharomyces sensu stricto group and exhibiting the range of prion domain divergence that overlaps with the range of divergence observed among distant mammalian species. Heterologous Sup35 proteins co-aggregated in S. cerevisiae cells. However, in vivo cross-species prion conversion was decreased and in vitro polymerization was cross-inhibited in at least some heterologous combinations, thus demonstrating the existence of prion species barrier. Our data suggests that species-specificity of prion transmission is controlled at the level of conformational transition rather than co-aggregation. We have shown the Sup35 prion domain is sufficient for the species barrier among the S. sensu stricto species, and constructed SUP35 chimeric prion domains, combining the subregions of various origins Our data demonstrated in different cross-species combinations, different modules of prion domain play a crucial role in the controlling of species-specificity of prion transmission. One essential amino acid position has been identified in S. cerevisiae and S. paradoxus system. Our data support a model suggesting that identity of the short amyloidogenic sequences is crucial for the species barrier. Sup35 originated from three different species of the S. sensu stricto group were capable of forming a prion in S. cerevisiae. However, it was not known whether they are capable of generating and maintaining the prion state in the homologous cell environment. We have constructed the S. paradoxus and S. bayanus strains with appropriate markers, and we were able to demonstrate de novo [PSI+] formation in S. paradoxus but not in S. bayanus. Our data show that [PSI+] formation is not a unique property of S. cerevisiae.
Advisors/Committee Members: Chernoff, Yury (Committee Chair), Bommarius, Andreas (Committee Member), Doyle, Donald (Committee Member), Lobachev, Kirill (Committee Member), Yi, Soojin (Committee Member).
Subjects/Keywords: Species barrier; S. paradoxus; S. cerevisiae; Prion; S. bayanus; Prions; Prion diseases; Yeast; Communicable diseases
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APA ·
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MLA ·
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APA (6th Edition):
Chen, B. (2008). Prion species barrier at the short phylogenetic distances in the yeast model. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/29762
Chicago Manual of Style (16th Edition):
Chen, Buxin. “Prion species barrier at the short phylogenetic distances in the yeast model.” 2008. Doctoral Dissertation, Georgia Tech. Accessed January 22, 2021.
http://hdl.handle.net/1853/29762.
MLA Handbook (7th Edition):
Chen, Buxin. “Prion species barrier at the short phylogenetic distances in the yeast model.” 2008. Web. 22 Jan 2021.
Vancouver:
Chen B. Prion species barrier at the short phylogenetic distances in the yeast model. [Internet] [Doctoral dissertation]. Georgia Tech; 2008. [cited 2021 Jan 22].
Available from: http://hdl.handle.net/1853/29762.
Council of Science Editors:
Chen B. Prion species barrier at the short phylogenetic distances in the yeast model. [Doctoral Dissertation]. Georgia Tech; 2008. Available from: http://hdl.handle.net/1853/29762
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Open Access Theses and Dissertations
