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You searched for subject:(l rare). Showing records 1 – 3 of 3 total matches.

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University of Georgia

1. Han, Qi. Reducing degradation of intracellular cofactors to improve bioconversion to oxidized chemicals and production of recombinant proteins by escherichia coli.

Degree: PhD, Biological and Agricultural Engineering, 2018, University of Georgia

Microorganisms are widely used to synthesize chemicals. One set of microbial conversions involves the transfer of electron from a starting material to a microbial electron carrier (such as NAD+): A + NAD+ to B + NADH. L-xylulose formation is a good example of this microbial conversion, which is a rare sugar generated from xylitol by an NAD+-dependent xylitol 4-dehydrogenase (XDH) from Pantoea ananatis. Since the general conversion of A to B (or the specific example of xylitol to L-xylulose) involves the utilization of NAD+ and the formation of NADH, the continued presence of NAD+ is necessary to drive the process. Two fundamental challenges exist, however. First, to drive the reaction forward at a fast rate toward the product, a relatively high ratio of NAD+/NADH is required. Second, microbes continually degrade both NAD+ and NADH as part of biochemical recycling that occurs in living systems, which will lead essentially to a loss of NAD(H) availability. Using the conversion of xylitol to L-xylulose as a model system, we co-expressed water-forming NADH oxidase (NOX) from Streptococcus pneumoniae with XDH to regenerate NAD+, and also modified the biochemical pathways involved in NAD(H) degradation. Controlled batch process demonstrated that the final equilibrium L-xylulose/xylitol ratio was correlated to an elevated ratio of NAD+/NADH. The E. coli strain (MEC697) with deletions of the nadR nudC mazG genes in the degradation pathway of NAD(H) increased the total amount of NAD(H) and delayed the degradation of this cofactor, further improving the conversion of xylitol to L-xylulose. As a potential platform for enhancing formation of the oxidized biochemical product, MEC697 also successfully improved the conversion of galactitol to L-tagatose, with almost a 60% increase in the final product. In addition, MEC697 reduced the acetate formation when grown on glucose and improved galactosidase production. Using steady-state cultures, we demonstrated the enhanced total NAD(H) in MEC697 delayed the threshold growth rate for acetate formation to beyond 0.27 h-1. At the 1 liter scale, a batch process with 10 g/L glucose, MEC697 as the host strain for recombinant protein production reduced acetate by about 50% and doubled the formation of galactosidase. Advisors/Committee Members: Mark Eiteman.

Subjects/Keywords: Escherichia coli; Rare sugars; Recombinant protein; NAD+/NADH; Xylitol 4-dehydrogenase; NADH oxidase; galactosidase; Glucose; Glycerol; Xylitol; L-xylulose; Acetate; Batch process; Chemostat

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APA (6th Edition):

Han, Q. (2018). Reducing degradation of intracellular cofactors to improve bioconversion to oxidized chemicals and production of recombinant proteins by escherichia coli. (Doctoral Dissertation). University of Georgia. Retrieved from http://hdl.handle.net/10724/38600

Chicago Manual of Style (16th Edition):

Han, Qi. “Reducing degradation of intracellular cofactors to improve bioconversion to oxidized chemicals and production of recombinant proteins by escherichia coli.” 2018. Doctoral Dissertation, University of Georgia. Accessed February 27, 2020. http://hdl.handle.net/10724/38600.

MLA Handbook (7th Edition):

Han, Qi. “Reducing degradation of intracellular cofactors to improve bioconversion to oxidized chemicals and production of recombinant proteins by escherichia coli.” 2018. Web. 27 Feb 2020.

Vancouver:

Han Q. Reducing degradation of intracellular cofactors to improve bioconversion to oxidized chemicals and production of recombinant proteins by escherichia coli. [Internet] [Doctoral dissertation]. University of Georgia; 2018. [cited 2020 Feb 27]. Available from: http://hdl.handle.net/10724/38600.

Council of Science Editors:

Han Q. Reducing degradation of intracellular cofactors to improve bioconversion to oxidized chemicals and production of recombinant proteins by escherichia coli. [Doctoral Dissertation]. University of Georgia; 2018. Available from: http://hdl.handle.net/10724/38600

2. Pepper, George H. L X-Ray Production in the Rare Earths by 0.33-2.66-MeV/amu Carbon- and 0.50-2.25-MeV/amu Oxygen-Ion Bombardment.

Degree: 1975, North Texas State University

Experimentally measured L-shell x-ray production cross sections are presented for 8-36-MeV oxygen-ion bombardment of Ce, Pr, Sm, Eu, Dy, and Ho; for 4-32-MeV carbon-ion bombardment of La and Yb; for 6-32-MeV carbon-ion bombardment of Pr, Nd, Sm, and Dy; and for ll-29-MeV carbon-ion bombardment of Ce, Eu, Gd, and Ho. Theoretical predictions via the plane wave Born approximation (PWBA) with corrections for increased binding of target electrons and Coulomb deflection of the incident projectile tend to underestimate the experimental data; and this underestimation tends to get worse at the low- and high-energy ends of the range of energies used in this work. Advisors/Committee Members: Gray, Thomas, Muthu, R. Muthu, Seiler, David G., McIntyre, Bernard, Foster, Bruce P..

Subjects/Keywords: L-shell; ion bombardment; Cross sections (Nuclear physics); Rare earths.; Ionization.; Ion bombardment.

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APA (6th Edition):

Pepper, G. H. (1975). L X-Ray Production in the Rare Earths by 0.33-2.66-MeV/amu Carbon- and 0.50-2.25-MeV/amu Oxygen-Ion Bombardment. (Thesis). North Texas State University. Retrieved from https://digital.library.unt.edu/ark:/67531/metadc500238/

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Pepper, George H. “L X-Ray Production in the Rare Earths by 0.33-2.66-MeV/amu Carbon- and 0.50-2.25-MeV/amu Oxygen-Ion Bombardment.” 1975. Thesis, North Texas State University. Accessed February 27, 2020. https://digital.library.unt.edu/ark:/67531/metadc500238/.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Pepper, George H. “L X-Ray Production in the Rare Earths by 0.33-2.66-MeV/amu Carbon- and 0.50-2.25-MeV/amu Oxygen-Ion Bombardment.” 1975. Web. 27 Feb 2020.

Vancouver:

Pepper GH. L X-Ray Production in the Rare Earths by 0.33-2.66-MeV/amu Carbon- and 0.50-2.25-MeV/amu Oxygen-Ion Bombardment. [Internet] [Thesis]. North Texas State University; 1975. [cited 2020 Feb 27]. Available from: https://digital.library.unt.edu/ark:/67531/metadc500238/.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Pepper GH. L X-Ray Production in the Rare Earths by 0.33-2.66-MeV/amu Carbon- and 0.50-2.25-MeV/amu Oxygen-Ion Bombardment. [Thesis]. North Texas State University; 1975. Available from: https://digital.library.unt.edu/ark:/67531/metadc500238/

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

3. Abrath, Frederick G. Proton-Induced L-shell X-Rays of Pr, Sm, Eu, Gd, and Dy.

Degree: 1974, North Texas State University

Characteristic L-shell x rays of the five rare earths Pr, Sm, Eu, Gd, and Dy were studied in this work. The x rays were produced by ionization from 0.3 to 2.0 MeV protons from the 2.0 MV Van de Graaff at North Texas State University. Total L-shell ionization and x-ray production cross sections were measured for Sm and compared to the BEA, CBEA and PWBA theories. Total L-shell ionization cross sections were measured for Pr, Eu, Gd, and Dy and compared to the BEA, CBEA, and PWBA. The CBEA and PWBA fit the samarium data well for both ionization and x-ray production cross sections. The BEA was generally 40 per cent lower than the data. The CBEA and the PWBA also fit the ionization cross section data for Pr, Eu, Gd and Dy, while the BEA was generally 40 per cent lower than the data. Advisors/Committee Members: Gray, Thomas James, 1917-, Redding, Rogers W., Foster, Bruce P., Seiler, David G., Krishnan, Raj Muthu.

Subjects/Keywords: L-shell x-rays; Rare earths  – Spectra.; Cross sections (Nuclear physics)  – Tables.; X-ray spectroscopy  – Tables.; L-shell ionization; x-ray production

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

APA (6th Edition):

Abrath, F. G. (1974). Proton-Induced L-shell X-Rays of Pr, Sm, Eu, Gd, and Dy. (Thesis). North Texas State University. Retrieved from https://digital.library.unt.edu/ark:/67531/metadc500284/

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Abrath, Frederick G. “Proton-Induced L-shell X-Rays of Pr, Sm, Eu, Gd, and Dy.” 1974. Thesis, North Texas State University. Accessed February 27, 2020. https://digital.library.unt.edu/ark:/67531/metadc500284/.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Abrath, Frederick G. “Proton-Induced L-shell X-Rays of Pr, Sm, Eu, Gd, and Dy.” 1974. Web. 27 Feb 2020.

Vancouver:

Abrath FG. Proton-Induced L-shell X-Rays of Pr, Sm, Eu, Gd, and Dy. [Internet] [Thesis]. North Texas State University; 1974. [cited 2020 Feb 27]. Available from: https://digital.library.unt.edu/ark:/67531/metadc500284/.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Abrath FG. Proton-Induced L-shell X-Rays of Pr, Sm, Eu, Gd, and Dy. [Thesis]. North Texas State University; 1974. Available from: https://digital.library.unt.edu/ark:/67531/metadc500284/

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

.