Ip Lai Fong. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references (leaves 81-92). / Abstracts in English and Chinese. / Table of Contents --- p.1 / Abbreviations --- p.4 / Chapter Chapter 1 --- Introduction and Background --- p.5 / Chapter 1.1 --- Endothelin system --- p.5 / Chapter 1.1.1 --- Endothelins --- p.5 / Chapter 1.1.2 --- Endothelin converting enzyme (ECE) isoforms --- p.12 / Chapter 1.1.3 --- Endothelin receptors --- p.24 / Chapter 1.2 --- Signal-transduction mechanisms in ET system --- p.27 / Chapter 1.3 --- The aim of the present thesis --- p.31 / Chapter Chapter 2 --- Materials and Methods --- p.32 / Chapter 2.1 --- Primer Design --- p.32 / Chapter 2.2 --- Total RNA Isolation --- p.33 / Chapter 2.3 --- Reverse transcriptase polymerase chain reaction (RT-PCR) --- p.34 / Chapter 2.3.1 --- First Strand cDNA Synthesis --- p.34 / Chapter 2.3.2 --- PCR reaction --- p.34 / Chapter 2.4 --- Agarose gel electrophoresis --- p.35 / Chapter 2.5 --- Ligation of PCR inserts to cloning vector by TA cloning method --- p.35 / Chapter 2.6 --- Competent cell preparation --- p.36 / Chapter 2.7 --- Transformation and Screening --- p.37 / Chapter 2.8 --- Plasmid DNA Extraction --- p.38 / Chapter 2.9 --- DNA sequencing --- p.38 / Chapter 2.10 --- DIG RNA Labeling --- p.38 / Chapter 2.10.1 --- Plasmid Linearization --- p.38 / Chapter 2.10.2 --- Transcription --- p.39 / Chapter 2.10.3 --- Probe purification --- p.39 / Chapter 2.11 --- In situ hybridizaion --- p.40 / Chapter 2.11.1 --- Tissue preparation and slide mounting --- p.40 / Chapter 2.11.2 --- Non-radioactive in situ hybridization --- p.41 / Chapter 2.12 --- Whole Mount non-radioactive in situ hybridization --- p.42 / Chapter 2.12.1 --- Dissection and fixation --- p.42 / Chapter 2.12.2 --- Hybridization --- p.43 / Chapter 2.12.3 --- Antibody incubation --- p.43 / Chapter 2.12.4 --- Histochemistry --- p.44 / Chapter Chapter 3 --- Results --- p.46 / Chapter 3.1 --- The molecular cloning of ECE-2 from rat brain --- p.46 / Chapter 3.2 --- Sequence characteristics of rat ECE-2 --- p.52 / Chapter 3.3 --- Comparison of rat ECE-2 with bovine and human ECE-2 and with the rat ECE-1 --- p.53 / Chapter 3.4 --- Tissue distribution of ECE-2 in rat and localization in C6 glial cells by RT-PCR --- p.60 / Chapter 3.5 --- ECE-2 in rat embryos at different gestation stages by RT-PCR --- p.60 / Chapter 3.6 --- ECE-2 distribution in C6 glioma cells --- p.63 / Chapter 3.7 --- ECE-2 distribution in rat embryo E15.5 --- p.63 / Chapter 3.8 --- ECE-2 distribution in rat brain sections --- p.63 / Chapter Chapter 4 --- p.74 / Discussion --- p.74 / References --- p.81

by Chung Wilson. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2002. / Includes bibliographical references (leaves 126-149). / Abstracts in English and Chinese. / Acknowledgements --- p.i / Abstract (English) --- p.ii / Abstract (Chinese) --- p.v / Content --- p.vii / Abbreviations --- p.xii / List of Figures --- p.xv / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Alzheimer's disease --- p.1 / Chapter 1.1.1 --- History of Alzheimer's disease --- p.1 / Chapter 1.1.2 --- Definition of Alzheimer's disease --- p.2 / Chapter 1.1.3 --- Symptoms of Alzheimer's disease --- p.6 / Chapter 1.1.3.1 --- Memory deficit --- p.6 / Chapter 1.1.3.2 --- Difficulty in learning --- p.6 / Chapter 1.1.3.3 --- Language difficulties --- p.7 / Chapter 1.1.3.4 --- Decline in ability to perform routine tasks --- p.7 / Chapter 1.1.4 --- Prevalence of Alzheimer's disease --- p.8 / Chapter 1.2 --- Present treatment of Alzheimer's disease --- p.9 / Chapter 1.2.1 --- Acetylcholine and dementia --- p.9 / Chapter 1.2.2 --- Tacrine as first drug approved by US Food and Drug Administration --- p.9 / Chapter 1.3 --- Proposed theory of Alzheimer's disease formation --- p.10 / Chapter 1.3.1 --- The amyloid cascade hypothesis --- p.10 / Chapter 1.3.1.1 --- The amyloid precursor protein --- p.10 / Chapter 1.3.1.2 --- The processing of amyloid precursor protein --- p.12 / Chapter 1.3.1.3 --- Neurotoxic effect of amyloid plaque --- p.15 / Chapter 1.3.1.4 --- Genetic factors --- p.15 / Chapter 1.3.1.4.1 --- The amyloid precursor protein --- p.15 / Chapter 1.3.1.4.2 --- Apolipoprotein E (ApoE) --- p.16 / Chapter 1.3.1.4.3 --- Presenilin genes --- p.17 / Chapter 1.3.2 --- Tau and tangle hypothesis --- p.19 / Chapter 1.3.2.1 --- Tau protein --- p.19 / Chapter 1.3.2.2 --- Paired helical filaments (PHF) --- p.20 / Chapter 1.3.2.3 --- Tau protein kinase --- p.20 / Chapter 1.3.2.3.1 --- Glycogen synthase kinase-3 (GSK-3) --- p.21 / Chapter 1.3.2.3.2 --- Cyclin-dependent kinase 5 (CDK5) --- p.21 / Chapter 1.3.2.4 --- Tangle leads to dementia --- p.22 / Chapter 1.4 --- Cross-talk between the two hypotheses --- p.24 / Chapter 1.5 --- β -secretase (BACE) --- p.24 / Chapter 1.5.1 --- Discovery of β-secretase (BACE) --- p.24 / Chapter 1.5.2 --- Detailed structure of BACE --- p.25 / Chapter 1.5.3 --- Comparsion of human and mouse BACE --- p.27 / Chapter 1.5.4 --- Comparsion of BACE-1 with BACE-2 --- p.27 / Chapter 1.5.5 --- Properties of BACE-1 --- p.28 / Chapter 1.5.6 --- Expression of BACE in E.coli --- p.29 / Chapter 1.5.7 --- Expression of BACE in mammalian cells --- p.30 / Chapter 1.6 --- Objectives of the present study --- p.32 / Chapter Chapter 2 --- Materials and Methods --- p.34 / Chapter 2.1 --- Recombinant DNA techniques --- p.34 / Chapter 2.1.1 --- Amplification of genes by PCR techniques --- p.34 / Chapter 2.1.2 --- Agarose gel electrophoresis --- p.34 / Chapter 2.1.3 --- Extraction of DNA from agarose gel --- p.35 / Chapter 2.1.4 --- Digestion of various vectors and inserts --- p.36 / Chapter 2.1.5 --- Ligation of DNA fragments --- p.36 / Chapter 2.1.6 --- Preparation of Escherichia coli competent cells --- p.37 / Chapter 2.1.7 --- Bacterial transformation --- p.38 / Chapter 2.1.8 --- Minipreparation of plasmid DNA --- p.38 / Chapter 2.1.9 --- Large scale preparation of plasmid DNA --- p.39 / Chapter 2.1.10 --- Strain storage and revival --- p.40 / Chapter 2.1.11 --- Plasma DNA purification by High Pure plasmid isolation kit --- p.41 / Chapter 2.1.12 --- DNA sequencing --- p.42 / Chapter 2.1.13 --- Quantitation of DNA by spectrophotometric method --- p.43 / Chapter 2.2 --- Prokaryotic protein expression --- p.43 / Chapter 2.2.1 --- Selection of appropriate clones for recombinant protein expression using conventional method --- p.43 / Chapter 2.2.2 --- Selection of appropriate clones for recombinant protein expression using modified method --- p.44 / Chapter 2.2.3 --- Large -scale expression of recombinant human BACE protein using modified method --- p.45 / Chapter 2.2.4 --- Preparation of inclusion body from the bacterial expression culture --- p.46 / Chapter 2.2.5 --- Refolding of human BACE --- p.47 / Chapter 2.2.6 --- Purification of recombinant human BACE by immobilized metal ion affinity chromatography (IMAC) --- p.47 / Chapter 2.2.7 --- Protein concentration determination --- p.48 / Chapter 2.2.8 --- Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) --- p.48 / Chapter 2.2.9 --- Western blotting --- p.50 / Chapter 2.2.10 --- Plasmid stability test --- p.50 / Chapter 2.3 --- Mammalian cell expression --- p.51 / Chapter 2.3.1 --- Transient transfection --- p.51 / Chapter 2.3.2 --- Measuring transfection efficiency --- p.52 / Chapter 2.3.3 --- Stable transfection --- p.52 / Chapter 2.3.4 --- Preparation of membrane extracts from CHO cells --- p.53 / Chapter 2.4 --- HPLC analysis --- p.53 / Chapter 2.4.1 --- Preparation of samples --- p.53 / Chapter 2.4.2 --- Reverse phase HPLC --- p.54 / Chapter 2.5 --- Fluorometric assay --- p.54 / Chapter 2.6 --- Immunohistochemistry --- p.55 / Chapter 2.7 --- Reagents and buffers --- p.55 / Chapter 2.7.1 --- Medium for bacterial culture --- p.56 / Chapter 2.7.2 --- Reagents for preparation of plasmid DNA --- p.56 / Chapter 2.7.3 --- Buffers for agarose gel electrophoresis --- p.57 / Chapter 2.7.4 --- Buffers for SDS-PAGE --- p.58 / Chapter 2.7.5 --- Buffer for purification of protein --- p.60 / Chapter 2.7.6 --- Buffer for Western Blotting --- p.61 / Chapter 2.7.7 --- Culturing medium of CHO cells --- p.62 / Chapter 2.7.8 --- Solutions for estimating transfection efficiency --- p.63 / Chapter 2.7.9 --- Reagents for HPLC --- p.64 / Chapter 2.7.10 --- Reagents for fluorometric assays --- p.65 / Chapter 2.7.11 --- Reagents for Immunohistochemistry --- p.66 / Chapter Chapter 3 --- Results --- p.67 / Chapter 3.1 --- Expression of BACE in E. coli --- p.67 / Chapter 3.1.1 --- Cloning of truncated human and mouse BACE into pRSET --- p.67 / Chapter 3.1.2 --- Expression of BACE in BL21(DE3)LysS cells --- p.70 / Chapter 3.1.2.1 --- Expression of truncated mouse and human BACEin BL21(DE3)LysS cells using conventional method --- p.70 / Chapter 3.1.2.2 --- Expression of truncated mouse and human BACEin BL21(DE3)LysS cells using modified method --- p.72 / Chapter 3.1.3 --- Analysis of BACE activity of purified recombinant proteins --- p.76 / Chapter 3.1.3.1 --- Fluorometric analysis --- p.76 / Chapter 3.2 --- Expression of BACE in mammalian cells --- p.81 / Chapter 3.2.1 --- "Cloning of full length mouse and human BACE into pCDNA3, pCDNA4HisMax" --- p.81 / Chapter 3.2.2 --- Transient transfection --- p.84 / Chapter 3.2.2.1 --- Western blot analysis --- p.86 / Chapter 3.2.2.2 --- Fluorometric analysis --- p.88 / Chapter 3.2.2.3 --- HPLC --- p.91 / Chapter 3.2.3 --- Stable transfection --- p.100 / Chapter 3.2.3.1 --- Western blot analysis --- p.101 / Chapter 3.2.3.2 --- Fluorometric analysis --- p.103 / Chapter 3.2.3.3 --- HPLC --- p.105 / Chapter 3.2.3.4 --- Immunohistochemistry --- p.112 / Chapter Chapter 4 --- Discussion --- p.115 / References --- p.126 / Appendix --- p.i / Chapter A1 --- Vector circle map --- p.i / Chapter A1-1 --- Vector circle map of pBluescript II- --- p.i / Chapter A1-2 --- Vector circle map of pCDNA3 --- p.ii / Chapter A1-3 --- Vector circle map of pCDNA4HisMax --- p.iii / Chapter A1-4 --- Vector circle map of pRSET --- p.iv / Chapter A2 --- Primer lists --- p.v / Chapter A3 --- Chemical structure of fluorophore and quench used in fluorometric assay --- p.vi

Variable-temperature Fourier transform infrared (VT-FTIR) spectroscopy in conjunction with 2D correlation analysis was employed to study the unfolding of aspartate transcarbamylase (ATCase) and its individual subunits. The regulatory subunit (RSU) was uniformly labeled with 13C/15N and then reconstituted with the unlabeled catalytic subunit (CSU) to form the holoenzyme. The activity of the holoenzyme was shown to be unaffected by the isotopic labeling of the RSU. The VT-FTIR investigation of the isolated CSU and the CSU in the holoenzyme revealed that the CSU is more thermally stable when bound to the RSU (i.e., in the holoenzyme). The RSU also showed more thermal stability when bound to the CSU. The sequences of events leading to the unfolding of the isolated CSU and RSU and the CSU in the holoenzyme were deduced by 2D correlation analysis of the VT-FTIR spectra. The results for the isolated CSU demonstrated that beta-sheets unfold first, followed by a-helices and then turns, and finally aggregates form. The sequence of unfolding of the RSU showed an increase of turns followed by a loss of intramolecular beta sheets, then a loss of alpha-helices and the formation of aggregates. The CSU in the holoenzyme exhibited a slightly different unfolding pathway and was observed to unfold subsequent to the unfolding of the RSU, consistent with the two thermal transitions observed by differential scanning calorimetry.

Fourier transform infrared (FTIR) spectroscopy is a powerful tool for probing protein structure-function relationships. With the use of isotope editing, it can also be employed to elucidate protein-nucleic acid interactions. This technique was used to study the sequence of heat-induced unfolding of the uniformly labeled 13C regulatory subunit (RSU) of E. coli aspartate transcarbamylase (ATCase) with its inhibitor CTP. The absorption of CTP in the amide I' region limits our ability to detect protein conformational changes upon binding of CTP. Therefore, by labeling the protein with 13C shifts the amide I' band ~ 40 cm -1 and clearly separates the protein bands from those of CTP. Variable-temperature (VT) FTIR spectroscopy was then employed to monitor the thermal unfolding of the labeled RSU in the presence and absence of CTP. / In addition, isotope editing was further explored to probe domain-domain interactions of the two domains of RSU using intein technology. Intein technology provides a novel means by which isotope editing can be performed to extract information on protein inter-domain and inter-subunit interactions by spectroscopic analysis but has not yet been exploited in Fourier transform infrared (FTIR) spectroscopy. The objective of this project is to present for the first time the feasibility of segmental labeling through intein-mediated protein ligation (IPL) for the purpose of studying conformational changes by FTIR spectroscopy, using ATCase as a model enzyme. In the first phase of this project, the RSU of ATCase, which houses a Zn-binding domain and a nucleotide binding domain, was reconstructed from its isolated domains using commercially available intein-base expression vectors. As steps towards obtaining an isotope labeled RSU, we have fused each domain to separate inteins. Following affinity purification, the intein tags were chemically cleaved and the reactive ends of the two RSU domains were ligated together to form a peptide. Although ligation was successful, improved yields are required for the FTIR spectroscopic studies.

Title from PDF of title page (University of Missouri--Columbia, viewed on February 23, 2010). The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file. Dissertation advisor: Dr. Jonathan A. Green. Vita Includes bibliographical references.

Thesis (Ph.D.)--McMaster University, 2003. / Advisor: Gerard Wright. Includes bibliographical references. Also available via World Wide Web.

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In everybody’s lives, there are strong emotional or surprising events that, for being special, are vividly remembered for a lifetime. Sometimes, these memories include one-shot images or details of associated daily life events that, for being ordinary, should have been rapidly forgotten. Why and how does the brain form and retain detailed memories of trivial events? The synaptic tagging and capture (STC) hypothesis of memory formation (Frey & Morris, Nature 1997) provides a theoretical framework that might explain the formation of these flashbulb memories at a cellular level. The hypothesis suggests that strong events, producing long-lasting memories, might stabilise memory for weak events by up-regulating the synthesis of late-phase plasticity-related proteins in neurons encoding memory traces for both events. This thesis tests this prediction of the STC hypothesis during the formation of long-term place memory in rodents. First, two new behavioural tasks are developed which provide sensitive measures of rapidly acquired place memory persistence - a new one-trial place memory task in the “event arena” and a modified delayed matching-to-place (DMP) protocol in the watermaze. Persistence of place memory is assessed and compared in these tasks. Given the important role of NMDA receptor activation during STC mechanisms, the contribution of NMDA and AMPA receptor activation in the hippocampus for the encoding and retrieval of place memory, respectively, is also established. Finally, weak and strong encoding events, leading to the formation of either shortor long-lasting place memory in the watermaze DMP task, are characterized. A second series of experiments investigates the possibility of synergistic interactions between different encoding events that occur in two different watermazes. First, weak and strong encoding events are arranged to occur within a short time-window to test behavioural analogues of the “strong-before-weak” and “weak-before-strong” STC paradigms characterised in electrophysiological experiments in rat hippocampal slices (Frey and Morris, 1997, 1998b). Then, after establishing i) the time course and local specificity of protein synthesis inhibition by intra-hippocampal infusion of anisomycin in vivo, ii) the dependence of long-term memory for strong encoding events on protein synthesis in the hippocampus, and iii) the induction of transcriptional and translational mechanisms in the hippocampus by strong encoding events, a behavioural analogue of the “strong-before-strong” STC paradigm (Frey and Morris, 1997) is also investigated. The results of these experiments are supportive of i) a role for hippocampal NMDA receptor-mediated synaptic plasticity in the encoding of rapidly acquired place memory; ii) a role for hippocampal AMPA receptor-mediated synaptic transmission in both encoding and retrieval of memory; and iii) a role for transcriptional and translational mechanisms in the hippocampus in the stabilisation of place memory. However, no evidence could be found supporting the involvement of synaptic tagging and capture mechanisms during the formation of long-lasting place memory.

The hydrogenation of β-ketoesters over chirally modified Ni catalysts is a celebrated and thoroughly researched example of an enantioselective heterogeneous catalytic reaction. Enantioselective heterogeneous processes, although extremely attractive in terms of fewer complications in the separation of products from the catalyst, are hindered in their viability as industrial applications due to the lack of detailed knowledge on how chirality is conferred to the metal surface. Surface science techniques have afforded substantial progress into determining mechanisms between modifier, reactant and catalyst to explain the source of enantioselectivity of the system. In this study, a combination of solution and ultra-high vacuum (UHV)-based experiments allow a more realistic interpretation of the surface chemistry underpinning the catalytic reaction as the key step in achieving enantioselective performance is the adsorption of chiral modifiers from solution. The behaviour of (S)-aspartic acid and (S)-lysine on Ni{111} and their interaction with the prochiral β-ketoester methylacetoacetate is investigated in this study to understand their potential as chiral modifiers for the system. In UHV, scanning tunnelling microscopy (STM), reflection absorption infrared spectroscopy (RAIRS), and temperature programmed desorption (TPD) are used to analyse the conformation and order of the amino acids on the metal, and their thermal stability. Additionally, liquid-solid interface RAIRS and X-ray photoelectron spectroscopy (XPS) are used to examine the modified Ni surface, prepared under aqueous conditions, to give an accurate representation of the catalytic studies. It has been found highly likely that, for (S)-aspartic acid modified Ni{111}, enantioselective sites exist at step or step/kink defects, formed by corrosive leaching of the Ni substrate. Conversely, lysine appears to bind with a high sticking probability to Ni, in the form of lysine islands, and does not appear to etch the Ni chirally. Finally, similar experiments have been carried out on Au{111}, where lysine was found to chiral restructure the surface and form nanofingers, and 2D Ni clusters grown on Au{111} in order to investigate the formation of possible metal-organic frameworks.