The principal aim of this thesis was to investigate the effects of altering the energy density of the diet (kJ/g) on post-restriction weight regain in domestic cats and laboratory mice. Secondly, evidence for body weight regulation was examined in mice. In cats, consumption of the same number of calories of a low energy dense diet (with added water) induced significantly less weight rebound than a more energy dense diet (with no added water). This was accounted for by differences in physical activity, as cats on the low energy dense diet were significantly more active. It was assumed the less energy dense diet held cats in a perceived state of energy restriction and they were actively searching for more food. In mice, cellulose was used to alter the energy density of the diet. Post-restriction body weight rebound was also observed on an energy dense diet (no cellulose). However, body weight not did reach pre-restriction levels when consuming a low energy dense diet (with added cellulose) and digestibility was significantly reduced. It was likely that the fibre-rich induced a gut processing limit on the bulk of digestible food that could be consumed. Overall, the energy density of the diet was shown to modulate post-restriction body weight rebound, but results varied with species and the energy dilutant used. The implications for human weight management have yet to be elucidated. The second principle finding was that post-restriction hyperphagia was induced to replenish food deficiencies incurred during caloric restriction, rather than to replenish body mass loss in mice. This provided preliminary evidence for a ‘calorie-counting’ body weight regulatory system in mammals.

by Leung Sau-mei. / With: Two articles bound together subsequent to publication. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1990. / Bibliography: leaves 101-108. / Abstract --- p.i / Acknowledgements --- p.iv / List of Abbreviations --- p.v / Table of content --- p.vi / Chapter Section 1 --- Introduction / Chapter 1.1 --- The phenomenon of host controlled restriction and modification in bacteria --- p.2 / Chapter 1.2 --- Classification of restriction and modification systems --- p.3 / Chapter 1.3 --- The nomenclature system for restriction and modification systems --- p.8 / Chapter 1.4 --- Variety of type II restriction and modification systems --- p.9 / Chapter 1.5 --- Properties of type II restriction endonucleases --- p.11 / Chapter 1.5.1 --- Biological function --- p.11 / Chapter 1.5.2 --- Protein structure --- p.12 / Chapter 1.5.3 --- Genetics --- p.16 / Chapter 1.5.4 --- Cleavage mechanism --- p.18 / Chapter 1.5.5 --- Factors affecting optimal activity --- p.21 / Chapter 1.6 --- Aim of study --- p.27 / Chapter Section 2 --- Materials and methods / Chapter 2.1 --- Screening for type II restriction endonucleases --- p.28 / Chapter 2.1.1 --- Sources --- p.28 / Chapter 2.1.2 --- Preparation of crude enzyme extract --- p.29 / Chapter 2.1.3 --- Assay of restriction enzyme activity --- p.30 / Chapter 2.1.4 --- Characterization of strains --- p.31 / Chapter 2.2 --- Purification of restriction endonucleases --- p.31 / Chapter 2.2.1 --- Preparation of column materials --- p.32 / Chapter 2.2.2 --- Purification of BcoI --- p.33 / Chapter 2.2.3 --- "Purification of Bcol0278I, BspI, Bsu8646I and PvuHKU" --- p.33 / Chapter 2.2.4 --- Purification of Bsu8565I and Pei9403I --- p.33 / Chapter 2.2.5 --- Purification of Sol3335I --- p.34 / Chapter 2.3 --- Characterization of discovered restriction endonucleases --- p.34 / Chapter 2.3.1 --- Determination of recognition specificity --- p.34 / Chapter 2.3.2 --- Determination of cleavage specificity of BcoI --- p.35 / Chapter 2.3.3 --- Unit definition --- p.36 / Chapter 2.3.4 --- Assays for ionic requirement and optimal temperature --- p.37 / Chapter 2.3.5 --- Heat inactivation --- p.37 / Chapter 2.4 --- Construction of Bacillus coagulans SM1 genomic library --- p.38 / Chapter 2.4.1 --- Preparation of chromosomal DNA --- p.38 / Chapter 2.4.1.1 --- Restriction digestion of chromosomal DNA --- p.40 / Chapter 2.4.2 --- Large scale preparation of vector pBR322 DNA --- p.43 / Chapter 2.4.2.1 --- Restriction digestion of vector DNA --- p.44 / Chapter 2.4.2.2 --- Preparation of lambda insert DNA for control tests --- p.45 / Chapter 2.4.3 --- Ligation of insert and vector DNA --- p.46 / Chapter 2.4.4 --- Transformation --- p.46 / Chapter 2.4.4.1 --- Preparation of electro-competent cells --- p.46 / Chapter 2.4.4.2 --- Electro-transformation --- p.47 / Chapter 2.4.5 --- Rapid screening for the presence of plasmid --- p.49 / Chapter Section 3 --- Results / Chapter 3.1 --- Presence of type II restriction endonucleases --- p.50 / Chapter 3.2 --- Strain identification --- p.50 / Chapter 3.3 --- Purification and properties of the discovered restriction endonucleases --- p.52 / Chapter 3.3.1 --- BcoI --- p.55 / Chapter 3.3.2 --- "Bco10278I, BspI, Bsu8646I and PvuHKUI" --- p.59 / Chapter 3.3.3 --- Bsu8565I and Pei9403I --- p.65 / Chapter 3.3.4 --- Sol3335I --- p.70 / Chapter 3.4 --- Construction of Bacillus coagulans SM1 genomic library --- p.73 / Chapter 3.4.1 --- Preparation of chromosomal DNA --- p.73 / Chapter 3.4.1.1 --- Generation of 4-10 kb insert fragments --- p.73 / Chapter 3.4.2 --- Preparation of plasmid DNA --- p.75 / Chapter 3.4.3 --- Ligation of insert and vector DNA --- p.76 / Chapter 3.4.4 --- Rapid screening for the presence of plasmid --- p.77 / Chapter Section 4 --- Discussion / Chapter 4.1 --- Screening of type II restriction endonucleases --- p.79 / Chapter 4.1.1 --- Methods for screening of type II restriction endonucleases --- p.79 / Chapter 4.1.2 --- Factors affecting the detection of restriction endonucleases --- p.83 / Chapter 4.2 --- Purification of the discovered restriction endonucleases --- p.87 / Chapter 4.3 --- Characterization of discovered restriction endonucleases --- p.91 / Chapter 4.3.1 --- Determination of recognition site --- p.91 / Chapter 4.3.2 --- Determination of cleavage specificity --- p.93 / Chapter 4.4 --- Characteristics of the discovered restriction endonucleases --- p.95 / Chapter 4.5 --- Molecular cloning of BcoI --- p.96 / Chapter 4.6 --- Future prospects --- p.99 / References --- p.101 / Appendix I --- p.109

This paper develops an idea of saving ordinary uses of vague predicates from the Sorites by means of domain restriction. A tolerance level for a pred- icate, along a dimension, is a difference with respect to which the predicate is semantically insensitive. A central gap for the predicate+dimension in a domain is a segment of an associated scale, larger than this difference, where no object in the domain has a measure, and such that the extension of the predicate has measures on one side of the gap and the anti-extension on the other. The domain restriction imposes a central gap. / <p>Author count: 1;</p> / Vagueness and Context Factors

In their natural environment animals must balance their safety requirements (i.e., avoiding predation) with their need to satisfy their energy demands (i.e., securing food). How the brain integrates these competing demands to promote adaptive responding is not well understood. The current study examined the effects of chronic food restriction on rats' behavioural defense profiles in two animal models of anxiety; the shock-probe burying and elevated plus-maze tests. In agreement with previous research, food restriction dramatically increased rats' open-arm exploration in the plus-maze. By contrast, food restriction did not alter the duration of time rats spent burying an electrified probe in the shock-probe burying test. Furthermore, food restricted rats displayed increases in risk assessment behaviour in both tests. Animals’ behaviour in both animal models of anxiety does not suggest a food-restriction induced reduction in anxiety. Alternatively, the results suggest that rats' willingness to explore normally avoided open arenas is sensitive to their current energy demands. In particular, it appears that under conditions of food scarcity rodents adapt their defensive profiles in order to meet both safety needs and satisfy energy demands. Further, the dramatic shift in open-arm exploration displayed by food-restricted animals seems to involve activation (as indexed by cFos) of brain regions previously implicated in feeding behaviour and normal open arm avoidance. Notably, an interaction effect of feeding and testing was observed in the anterior basolateral amygdala. This nucleus may be involved in integrating the competing demands of safety and energy requirements. / Thesis (Master, Neuroscience Studies) -- Queen's University, 2008-09-18 16:58:44.385

No description available.

We study two related inequalities that arise in Harmonic Analysis: restriction type inequalities and isoperimetric inequalities. The (Lp, Lq) Restriction type inequalities have been the subject of much interest since they were first conceived in the 1960s. The classical restriction type inequality involving surfaces of non-vanishing curvature is only fully resolved in two dimensions and there have been a lot of recent developments to establish the conjectured (p,q) range in higher dimensions. However, it also interesting to consider what can be said for curves where the curvature does vanish. In particular we build upon a restriction result for homogeneous polynomial surfaces, using what is considered the natural weight - the one induced by the affine curvature of the surface. This is known to hold with a non-universal constant which depends in some way on the coefficients of the polynomial. In this dissertation we shall quantify that relationship. Restriction estimates (for curves or surfaces) using the affine curvature weight can be shown to lead to an affine isoperimetric inequality for such curves or surfaces. We first prove, directly, this inequality for polynomial curves, where the constant depends only on the degree of the underlying polynomials. We then adapt this method, to prove an isoperimetric inequality for a wide class of curves, which includes curves for which a restriction estimate is not yet known. Next we state and prove an analogous result of the relative affine isoperimetric inequality, which applies to unbounded convex sets. Lastly we demonstrate that this relative affine isoperimetric inequality for unbounded sets is in fact equivalent to the classical affine isoperimetric inequality.

The paper talks about the topic of pursuing the perfect body and how we are controlled by the standards of per- fections. I chose this topic because of the development of the Chinese gym industry and personal experience . Many people try to pursue the standards of perfect bodies and use these standards to define themselves. Most people take it for granted that our bodies should look a certain way. In this paper, I want to question these standards and raise people’s awareness of the image of their bodies. I will also talk about my opinions about bodies.   In my practical work, I mix different metals with different values into one piece and shape the material into vessel forms. I use the material and the forms to question perfections and the attitude towards bodies in the society . Then I make the vessels into jewelry pieces to discuss how our bodies are treated as jewelry . I use my jewelry works to question what our bodies are and help people see their bodies in a different perspective.

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Sucrose content is one of the important seed quality traits in soybean, especially for oriental soyfood production. However, little genetic information is available on this quantitative trait yet. A previous study was conducted on seed sucrose content of soybean using a population of F2-derived lines from an interspecific cross between an adapted high-sucrose (8.3%) G. max breeding line (V71-370) and a low sucrose (1.6%) G. soja plant introduction (PI407162). Nineteen marker loci, mapping to seven linkage groups (A1, A2, E, F, L1, I, and M), were significantly associated with seed sucrose content after screening 178 polymorphic genetic markers, including RFLPs, SSRs, RAPDs and morphological markers. The replicated field experiments were planted in 1993 and 1995. The objective of my study was to evaluate QTLs associated with seed sucrose content utilizing an additional 153 F2:3 families from the same cross. DNA samples from the additional families were analyzed with the nineteen genetic markers associated with sucrose in the previous study. Sucrose data were obtained from seeds harvested from a field experiment conducted in 1995. Single factor analysis of variance results for the sucrose data obtained from the 153 F2:3 families were compared to the 1995 data for the 144 F2:3 families of the previous study. Of the nineteen genetic markers significantly associated with seed sucrose content in the previous study, seven were also significantly associated in this study. These genetic markers include sgA458a on linkage group A2, NBS61 on linkage group E, sgB164, R-B4a and sgB162 on linkage group L1, and R-B4b and sgA144 on linkage group I. The percent phenotypic variation explained by significant individual markers varied from 2.9 to 6.8% in the 153 F2:3 families. This study shows that seed sucrose content, a quantitative trait, may be improved using the molecular marker technology. Further research is necessary in different genetic backgrounds of G. max in order to implement these markers in a breeding program for selection. / Master of Science

Bacteria employ survival strategies to protect themselves against foreign invaders, including bacteriophages. The ‘immune system’ of bacteria relies mostly on restriction-modification (R-M) systems. The primary role of R-M systems is to protect the host from invading foreign DNA molecules. Three major types of R–M system are found in bacteria, viz.Types I, II and III. Type II R–M systems comprise a separate restriction endonuclease (REase) and a methyltransferase (MTase) that act independently of each other. Type II REases generally recognize palindromic sequences in DNA and cleave within or near their recognition sequences and produce DNA fragments of defined sizes. They have become indispensable tools in molecular biology and have been widely exploited for studying site-specific protein–DNA interactions. Surprisingly, these enzymes share little or no sequence homology among them, though the three-dimensional structures determined to date reveal a common-core motif (‘PD...D/EXK’ motif) with a central β-sheet that is flanked by α-helices on both sides. In the motif, two acidic residues (D and D/E) are important for the metal ion binding and catalysis. The work presented in this thesis deals with the determination of active site, elucidation of kinetic mechanism and study of evolution of sequence specificity using the well known, R.KpnI, from Klebsiella pneumoniae. The enzyme is a homodimer, which recognizes a palindromic double stranded DNA sequence, GGTAC↓C, and cleaves as shown. Unlike other REases, R.KpnI shows prolific promiscuous DNA cleavage in presence of Mg2+. Surprisingly, Ca2+ completely suppresses the Mg2+ mediated promiscuous activity and induces high fidelity cleavage at the recognition sequence. These unusual properties of R.KpnI led to the characterization of the active site of the enzyme. This thesis is divided into five chapters. Chapter 1 is a general introduction of R-M systems and an overview of the literature on active sites of Type II REases. It deals with discovery, nomenclature and classification followed by description of the enzymes diversity and general features of Type II REases. The different active site folds of the REases have been discussed in detail. The features of sequence specificity and the efforts undertaken to engineer the new specificity in the REases have been dealt at the end of the chapter. Chapter 2 describes identification and characterization of the R.KpnI active site by bioinformatics analyses, homology modeling and mutational studies. Bioinformatics analyses reveal that R.KpnI contains a ββα-Me-finger fold, which is a characteristic of many HNH-superfamily endonucleases. According to the homology model of R.KpnI, the putative active site residues correspond to the conserved residues present in HNH nucleases. Substitutions of these conserved residues in R.KpnI resulted in loss of the DNA cleavage activity, confirming their importance. This study provides the first experimental evidence for a Type IIP REase that is a member of the HNH superfamily and does not belong to the PD...D/EXK superfamily of nucleases. In Chapter 3 DNA binding and kinetic analysis of R.KpnI is presented. The metal ions which exhibit disparate pattern of DNA cleavage have no role in DNA recognition. The enzyme binds to both canonical and non-canonical DNA with comparable affinity irrespective of the metal ions used. Further, it was shown that Ca2+-imparted exquisite specificity of the enzyme is at the level of DNA cleavage and not at the binding step. The kinetic constants were obtained through steady-state kinetic analysis of R.KpnI in presence of different metal ions. With the canonical oligonucleotides, the cleavage rate of the enzyme was comparable for both Mg2+- and Mn2+-mediated reactions and was about three times slower with Ca2+. The enzyme discriminates non-canonical sequences poorly from the canonical sequence in Mg2+-mediated reactions unlike any other Type II REases, accounting for its promiscuous behavior. These studies suggest that R.KpnI displays properties akin to that of typical Type II REases and also endonucleases with degenerate specificity for DNA recognition and cleavage. In chapter 4, two uncommon roles for Zn2+ in R.KpnI are described. Examination of the sequence revealed the presence of a zinc finger (CCCH) motif rarely found in proteins of prokaryotic origin. Biophysical experiments and subsequent mutational analysis showed that the zinc binding motif tightly coordinates zinc to provide a rigid structural framework for the enzyme needed for its function. In addition to this structural scaffold, another atom of zinc binds to the active site to induce high fidelity cleavage and suppress the Mg2+- and Mn2+-mediated promiscuous behavior of the enzyme. This is the first demonstration of distinct structural and catalytic roles for zinc in a REase. Chapter 5 describes generation of highly sequence specific R.KpnI. Towards this end, site-directed mutants were generated at the putative secondary metal binding site. The DNA binding and cleavage analyses of the mutants at putative secondary metal binding site revealed that the secondary site is not important for primary catalysis and have a role in sequence specificity. A single amino acid change at the D163 position abolished the promiscuous activity of the wt enzyme in the presence of Mg2+ and Mn2+. Thus, a single point mutation converts the promiscuous endonuclease to a high fidelity REase. In conclusion, the work described in the thesis reveals new information on the REases in general and R.KpnI in particular. Many of the properties of R.KpnI elucidated in this thesis represent hitherto unknown features amongst REases. The presence of an HNH catalytic motif in the enzyme indicates the diversity of active site fold in REases and their distinct origin. Similarly, the high degree of promiscuity exhibited by the enzyme may hint at the evolutionary link between non-specific and highly sequence specific nucleases. The present studies also provide an example for the role of mutations in the evolution of sequence specificity. The utilization of different metal ions for DNA cleavage and the architectural role for Zn2+ in maintaining the structural integrity are other unusual properties of the enzyme.