He, Guoyun. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (leaves 62-69). / Abstracts in English and Chinese. / Title Page --- p.i / Abstract (English Version) --- p.iv / Abstract (Chinese Version) --- p.v / Acknowledgement --- p.vi / List of Tables --- p.ix / List of Figures --- p.x / List of Abbreviations and Symbols --- p.xii / Chapter Chapter One: --- Introduction --- p.1 / Chapter 1.1 --- Mismatches in DNA Duplex --- p.1 / Chapter 1.2 --- T.T Mismatches in DNA Duplex --- p.5 / Chapter 1.3 --- Purpose of the Work --- p.7 / Chapter 1.4 --- DNA Structure --- p.7 / Chapter 1.4.1 --- Structure and Nomenclature of Nucleotide --- p.7 / Chapter 1.4.2 --- Base Pairing --- p.8 / Chapter 1.4.3 --- Double Helical DNA Conformation --- p.9 / Chapter Chapter Two: --- Materials and Methods --- p.10 / Chapter 2.1 --- Sample Design --- p.10 / Chapter 2.2 --- Sample Preparation --- p.11 / Chapter 2.3 --- NMR Study --- p.11 / Chapter 2.3.1 --- Non-labile Proton Resonance Assignment --- p.12 / Chapter 2.3.2 --- Labile Proton Resonance Assignment in Normal Base Pairs --- p.13 / Chapter 2.3.3 --- Method to Determine T.T Pairing Mode --- p.14 / Chapter Chapter Three: --- Determination of T.T Pairing Mode --- p.16 / Chapter 3.1 --- NMR Resonance Assignment --- p.16 / Chapter 3.2 --- Result --- p.18 / Chapter 3.2.1 --- Preferential Pairing Mode: W --- p.18 / Chapter 3.2.2 --- Preferential Pairing Mode: W --- p.19 / Chapter 3.2.3 --- Exchanging and Pairing Modes --- p.20 / Chapter 3.3 --- Discussion --- p.23 / Chapter 3.3.1 --- Patterns of T.T Pairing Mode --- p.23 / Chapter 3.3.2 --- Reason for Preferential Pairing Mode --- p.24 / Chapter 3.3.3 --- Temperature Effect on T.T Pairing Mode --- p.26 / Chapter Chapter Four: --- Conclusions and Future Works --- p.29 / Chapter Appendix I: --- NOESY and WATERGATER-NOESY Assignment --- p.30 / Chapter Appendix II: --- Chemical Shifts of XTY --- p.46 / References --- p.62

Graduation date: 1995

published_or_final_version / Physiology / Master / Master of Philosophy

Not available / text

No description available.

The synthesis of the tertbutyldimethylsilyl derivatives of adenosine is described. The 2',5'-protected nucleosides were rapidly and easily prepared in relatively good yields. / The silylated nucleosides are easily incorporated into ribonucleotides using the fast and efficient dichlorophosphite method. The ribonucleotide GpCpApApCpCpA corresponding to the 3'-terminus of / (DIAGRAM, TABLE OR GRAPHIC OMITTED...PLEASE SEE DAI) / was successfully synthesized in a stepwise fashion. The stepwise and block condensation pathways were compared in the synthesis of CpCpCpCpC. The syntheses of A2'p5'A2'p5'A and other 2',5'- and symmetrically-linked ribonucleotides were readily accomplished. ('31)P NMR was very useful in elucidating the structure of the diribonucleoside monophosphates. A study of the effect of temperature and solvents on yield of final product is undertaken. Various phosphate protecting groups are also evaluated. / A suitable deprotection procedure is investigated and the identity of the phosphate linkages confirmed by enzyme degradations.

The nucleic acids digested by ruminants are essentially of microbial origin. Absorbed purines are extensively degraded and excreted in urine as allantoin, uric acid, xanthine and hypoxanthine. The measurement of the urinary purine derivatives could be used to estimate the uptake of purines and hence that of microbial protein. 1) Automated methods for measurements of purine derivatives were improved. A HPLC method for determining total adenine and guanine was used to measure the purine contents of mixed rumen bacteria and the digestibility of microbial purines in sheep. 2) Endogenous excretions of purine derivatives by sheep and cattle of different physiological states were measured using animals nourished by intragastric infusions of VFA and casein. The species difference in and the effects of changes in protein supply on the endogenous excretion were studied. 3) A microbial nucleic acid extract was infused into the abomasum of lambs at 6 levels. The subsequent urinary excretion of purine derivatives was examined. The results suggested that exogenous purines were utilised by the sheep. A model is proposed to describe the relationship between purine derivative excretion and purine uptake. 4) Allantoin was infused intravenously to sheep and the changes in plasma concentration, nephric tubular re-absorption and urinary excretion of allantoin were studied. Results showed that plasma allantoin was rapidly removed and a constant proportion of the allantoin entering the blood was excreted in urine of sheep. 5) Secretion of allantoin and uric acid into the gut via saliva was quantified in sheep. The possible decomposition of the allantoin in the rumen by microbes in the rumen fluid and in the rumen wall of sheep was examined <i>in vitro</i> and <i>in vivo</i>. Allantoin infused into the rumen or abomasum of sheep and cattle was not recovered in urine. 6) A model for calculation of microbial protein available to sheep is proposed. It is suggested that a different model should be used for cattle. These models were applied in two feeding experiments with sheep and steers.

Thesis (Ph. D.)--Rutgers University, 2010. / "Graduate Program in Chemistry and Chemical Biology." Includes bibliographical references.

Thesis (M.S.)--University of Wisconsin--Madison. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (M.S.)--University of Wisconsin--Madison, 1966. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.