Physical Sciences and Mathematics Commons^™

Molecular Dynamics Analysis Of Apolipoprotein-D - Lipid Hydroperoxide Interactions: Mechanism For Selective Oxidation Of Met-93, Aaron J. Oakley, Surabhi Bhatia, Heath Ecroyd, Brett Garner

Heath Ecroyd

Background: Recent studies suggest reduction of radical-propagating fatty acid hydroperoxides to inert hydroxides by interaction with apolipoprotein-D (apoD) Met93 may represent an antioxidant function for apoD. The nature and structural consequences of this selective interaction are unknown. Methodology/Principal Findings: Herein we used molecular dynamics (MD) analysis to address these issues. Longtimescale simulations of apoD suggest lipid molecules are bound flexibly, with the molecules free to explore multiple conformations in a binding site at the entrance to the classical lipocalin ligand-binding pocket. Models of 5s- 12s- and 15s hydroperoxyeicosatetraenoic acids were created and the lipids found to wrap around Met93 thus …

Base-Induced Decomposition Of Alkyl Hydroperoxides In The Gas Phase. Part 3. Kinetics And Dynamics In Ho + Ch3ooh, C2h5ooh, And Tert-C4h9ooh Reactions, Shuji Kato, G Barney Ellison, Veronica Bierbaum, Stephen J. Blanksby

Stephen Blanksby

The ECO2 elimination reactions of alkyl hydroperoxides proceed via abstraction of an α-hydrogen by a base: X− + R1R2HCOOH → HX + R1R2CO + HO−. Efficiencies and product distributions for the reactions of the hydroxide anion with methyl, ethyl, and tert-butyl hydroperoxides are studied in the gas phase. On the basis of experiments using three isotopic analogues, HO− + CH3OOH, HO− + CD3OOH, and H18O− + CH3OOH, the overall intrinsic reaction efficiency is determined to be 80% or greater. The ECO2 decomposition is facile for these methylperoxide reactions, and predominates over competing proton transfer at the hydroperoxide moiety. The CH3CH2OOH …

Dynamics Of Land Use/Land Cover Changes And Its Implication On Food Security In Anyigba, North Central, Nigeria, Tokula E. Arome, Sunday P. Ejaro (Phd)

Confluence Journal Environmental Studies (CJES), Kogi State University, Nigeria

This study assessed land use/land cover changes and its effect on Agricultural land in Anyigba. The objectives were to identify and delineate different land use / land cover categories, assess the rate of change that occurred and examine the impact of land use/land cover change on food security using satellite remote sensing data collected at three different years (1987 Land sat TM, 2001 Land Sat TM and 2011 Land Sat ETM). The study utilized GIS software such as Idrisi Andes academic and ArcGIS 9.3. The study area covers approximately 31.8km2, and four major land use/cover classes were utilized (built up, …

Dynamics Of The Solvent Exchange Reaction Of Weakly Bound Organic Solvents To Group 6 Transition Metal Carbonyls And The Molybdenum Hexacarbonyl Mediated Pauson-Khand Reaction, Richard J. Gates

Theses and Dissertations

Many organometallic reactions are solvent-dependent, suggesting solvent molecules interact with reaction intermediates. Studies of the solvent exchange reaction of group 6 transition metal carbonyls with moderately binding ligands have provided insight into these interactions, however, studies of the mechanism for this reaction with weakly binding ligands have not been performed. Experiments were conducted on the nanosecond time scale in methylcyclohexane over the temperature range of 4 to 44 °C using Step Scan FTIR (SS FTIR) spectroscopy with weakly binding ligands benzene and mesitylene. Upon photolysis of the metal hexacarbonyls, the kinetically favored product (M(CO)5(solv)), decays following pseudo-first-order kinetics to the …

Activity And Molecular Dynamics Relationship Within The Family Of Human Cholinesterase, Judith Peters, Marie Trovaslet, Marcus Trapp, Florian Nachon, Flynn Hill, Etienne Royer, Frank Gabel, Lambert Van Eijck, Patrick Masson, Moeava Tehei

Faculty of Science - Papers (Archive)

The temperature dependence of the dynamics of recombinant human acetylcholinesterase (hAChE) and plasma human butyrylcholinesterase (hBChE) is examined using elastic incoherent neutron scattering. These two enzymes belong to the same family and present 50% amino acid sequence identity. However, significantly higher flexibility and catalytic activity of hAChE when compared to the ones of hBChE are measured. At the same time, the average height of the potential barrier to the motions is increased in the hBChE, e.g. more thermal energy is needed to cross it in the latter case, which might be the origin of the increase in activation energy and …

Molecular Dynamics Analysis Of Apolipoprotein-D - Lipid Hydroperoxide Interactions: Mechanism For Selective Oxidation Of Met-93, Aaron J. Oakley, Surabhi Bhatia, Heath Ecroyd, Brett Garner

Faculty of Science - Papers (Archive)

Background: Recent studies suggest reduction of radical-propagating fatty acid hydroperoxides to inert hydroxides by interaction with apolipoprotein-D (apoD) Met93 may represent an antioxidant function for apoD. The nature and structural consequences of this selective interaction are unknown.

Methodology/Principal Findings: Herein we used molecular dynamics (MD) analysis to address these issues. Longtimescale simulations of apoD suggest lipid molecules are bound flexibly, with the molecules free to explore multiple conformations in a binding site at the entrance to the classical lipocalin ligand-binding pocket. Models of 5s- 12s- and 15s hydroperoxyeicosatetraenoic acids were created and the lipids found to wrap around Met93 thus …

Telomere Dynamics And Homeostasis In A Transmissible Cancer, Beata Ujvari, Anne-Maree Pearse, Robyn Taylor, Stephen Pyecroft, Cassandra Flanagan, Sara Gombert, Anthony T. Papenfuss, Thomas R. Madsen, Katherine Belov

Faculty of Science - Papers (Archive)

Background: Devil Facial Tumour Disease (DFTD) is a unique clonal cancer that threatens the world's largest carnivorous marsupial, the Tasmanian devil (Sarcophilus harrisii) with extinction. This transmissible cancer is passed between individual devils by cell implantation during social interactions. The tumour arose in a Schwann cell of a single devil over 15 years ago and since then has expanded clonally, without showing signs of replicative senescence; in stark contrast to a somatic cell that displays a finite capacity for replication, known as the "Hayflick limit". Methodology/Principal Findings: In the present study we investigate the role of telomere length, measured as …

From Ecophysiology To Phenomics: Some Implications Of Photoprotection And Shade-Sun Acclimation In Situ For Dynamics Of Thylakoids In Vitro, Shizue Matsubara, Britta Forster, Melinda Waterman, Sharon A. Robinson, Barry J. Pogson, Brian Gunning, Barry Osmond

Faculty of Science - Papers (Archive)

Half a century of research into the physiology and biochemistry of sun–shade acclimation in diverse plants has provided reality checks for contemporary understanding of thylakoid membrane dynamics. This paper reviews recent insights into photosynthetic efficiency and photoprotection from studies of two xanthophyll cycles in old shade leaves from the inner canopy of the tropical trees Inga sapindoides and Persea americana (avocado). It then presents new physiological data from avocado on the time frames of the slow coordinated photosynthetic development of sink leaves in sunlight and on the slow renovation of photosynthetic properties in old leaves during sun to shade and …

Book Review - Women In Leadership: Contextual Dynamics And Boundaries, Christine Eriksen

Faculty of Science - Papers (Archive)

Leadership scenarios and paradoxes - past, present and future - form the basis of Karin Klenke's analysis of women in leadership. The book sets out to explore the paradoxical nature of women's leadership in male-dominated contexts, paradoxes women leaders are confronted with, as well as the paradox of change versus the persistence of the status quo. Contexts with a 'paradoxical nature'- temporally and spatially - are at the forefront. These 'contexts' for women's leadership range from remarkable female leaders, today and historically, in politics, organisational structures, information technology (IT), the media, sports, the military, religion and spirituality, science, higher education …