Reconstitution and functional comparison of purified GlpF and AqpZ, the glycerol and water channels from Escherichia coli

A large family of membrane channel proteins selective for transport of water (aquaporins) or water plus glycerol (aquaglyceroporins) has been found in diverse life forms. Escherichia coli has two members of this family—a water channel, AqpZ, and a glycerol facilitator, GlpF. Despite having similar primary amino acid sequences and predicted structures, the oligomeric state and solute selectivity of AqpZ and GlpF are disputed. Here we report biochemical and functional characterizations of affinity-purified GlpF and compare it to AqpZ. Histidine-tagged (His-GlpF) and hemagglutinin-tagged (HA-GlpF) polypeptides encoded by a bicistronic construct were expressed in bacteria. HA-GlpF and His-GlpF appear to form oligomers during Ni-nitrilotriacetate affinity purification. Sucrose gradient sedimentation analyses showed that the oligomeric state of octyl glucoside-solubilized GlpF varies: low ionic strength favors subunit dissociation, whereas Mg2+ stabilizes tetrameric assembly. Reconstitution of affinity-purified GlpF into proteoliposomes increases glycerol permeability more than 100-fold and water permeability up to 10-fold compared with control liposomes. Glycerol and water permeability of GlpF both occur with low Arrhenius activation energies and are reversibly inhibited by HgCl2. Our studies demonstrate that, unlike AqpZ, a water-selective stable tetramer, purified GlpF exists in multiple oligomeric forms under nondenaturing conditions and is highly permeable to glycerol but less well permeated by water.

Cloning the human and mouse MMS19 genes and functional complementation of a yeast mms19 deletion mutant

The MMS19 gene of the yeast Saccharomyces cerevisiae encodes a polypeptide of unknown function which is required for both nucleotide excision repair (NER) and RNA polymerase II (RNAP II) transcription. Here we report the molecular cloning of human and mouse orthologs of the yeast MMS19 gene. Both human and Drosophila MMS19 cDNAs correct thermosensitive growth and sensitivity to killing by UV radiation in a yeast mutant deleted for the MMS19 gene, indicating functional conservation between the yeast and mammalian gene products. Alignment of the translated sequences of MMS19 from multiple eukaryotes, including mouse and human, revealed the presence of several conserved regions, including a HEAT repeat domain near the C-terminus. The presence of HEAT repeats, coupled with functional complementation of yeast mutant phenotypes by the orthologous protein from higher eukaryotes, suggests a role of Mms19 protein in the assembly of a multiprotein complex(es) required for NER and RNAP II transcription. Both the mouse and human genes are ubiquitously expressed as multiple transcripts, some of which appear to derive from alternative splicing. The ratio of different transcripts varies in several different tissue types.

Effect of the surface chemical groups of activated carbons on their surface adsorptivity to aromatic adsorbates based on π-π interactions

Three activated carbons with different surface chemical groups were used to analyse the influence of these groups on their adsorption capacities towards aromatic-type molecules whose adsorption is based on π-π interactions with surface arene centres. The three activated carbons studied were a low-functionalized carbon (Merck), an oxygen-rich carbon obtained by HNO3 oxidation of Merck, and a nitrogen-rich carbon also prepared from Merck by mild HNO3 oxidation followed by treatment with a dicyanodiamide/dimethyl formamide mixture at 300 °C. The nature of the surface chemical groups of the three activated carbons was investigated by both physical and chemical techniques (TPD, XPS, Boehm analysis and pH potentiometric titration). A systematic study of the adsorptions of a series of analogous aromatic adsorbates on the three activated carbons was carried out to study the adsorption mechanisms. In all cases the adsorption mechanism is based on π-π interactions between the aromatic moiety of the adsorbates and the arene centres of the graphite sheets. The differences in the normalized adsorption capacities of the adsorbents for a set of adsorbates indicate that the π-donor or π-withdrawing character of the functional groups have a clear influence on the basicity of the arene centres.

Journal of the Senate of the ... Legislative Assembly.

Includes special sessions.

Acts of the General Assembly of the State of South-Carolina.

Includes index.

Acts and resolutions passed at the first session of the General Assembly of the State of Iowa : which convened at Iowa City, on the thirtieth day of November, A.D. 1846.

Includes index.

The statutes at large; : being a collection of all the laws of Virginia, from the first session of the legislature, in the year 1619. : Published pursuant to an act of the General Assembly of Virginia, passed on the fifth day of February one thousand eight hundred and eight. : Volume I[-XIII]. /

Each volume contains a certification statement and an errata statement, either tipped in or printed on the title page verso.

The public statute laws of the state of Connecticut, compiled in obedience to a resolve of the General assembly, passed May 1835, to which is prefixed the Declaration of Independence, Constitution of the United States, and Constitution of the state of Connecticut. Published by the authority of the state.

Includes index.

Revised ordinances of the city of Winchester : together with the city charter, and other acts of the General Assembly relating to cities and towns.

Includes index.

Direct support and general support maintenance repair parts and special tools list (including depot maintenance repair parts and special tools) for TOW subsystem consisting of TOW launcher assembly, NSN 1440-01-085-5517, command guidance electronics, NSN 1430-01-085-5521.

Includes index.

Acts of the General Assembly of the state of Virginia, passed at called session, 1862 : in the eighty-seventh year of the Commonwealth.

Includes index.

Acts of the General Assembly of the State of Virginia, passed in 1866-67, in the ninety-first year of the Commonwealth.

Index for the Acts of 1865-66, 1866-67, and of the Extra session, 1867, at end of volume, with title: General index. Sessions 1865-6 and 1866-7.

The functional impact of developmental co-ordination disorder during adolescence and early adult life

PURPOSE: The purpose of this study was to increase the understanding of the functional impact that coordination problems have during adolescence and early adult life. In particular, this study aimed to investigate the impact coordination deficits have on day-to-day functioning, activity levels, self-concept with respect to coordination, leisure pursuits, occupational types, accidents and injuries, as well as experiences learning to drive. RELEVANCE: This study may enable clinicians to identify at risk situations, such that appropriate prevention and targeting of treatment can occur. SUBJECTS: The participants involved in this study comprised two groups; 40 subjects previously diagnosed with DCD, and their matched controls. METHODS: Participants were initially contacted by mail for their consent to the study. Consenting participants were then contacted via telephone, and interviewed. ANALYSES: Data analysis was performed using SPSS. Chi squared analysis and Mann Whitney U test was also used to compare groups. RESULTS: During both age periods, the number of DCD subjects participating in sport was significantly less than the number of controls. Although in the 12-14 years age category, the two groups displayed similar results for the type of sport chosen, the 18 – 20 years age group, showed significant differences, with the number of DCD subjects participating in High level coordination activities, being significantly less than controls. Self-perception with respect to coordination was also significantly different amongst groups with more DCD subjects, having perceived themselves as being clumsy. Similarly, a significantly greater number of DCD subjects admitted to tripping over themselves regularly. Some differences have also been noted in the experiences of subjects learning to drive. First, the number of DCD subjects, who had difficulties learning to drive was significantly greater than controls. Second, a much greater number of Control subjects, compared to DCD subjects were successful in obtaining drivers license. Finally, also of interest is the 58% of DCD subjects who have experienced an accident whilst driving, compared to the 35% of controls. The last result of this study was that whilst there was no significant difference between groups, in the number of broken bones, dislocated joints, sprain, burns, stitches, or other significant injuries, the number of control subjects suffering muscle strains was significantly greater than the number of DCD subjects. CONCLUSION: The results of this study indicate that DCD has many implications on day-to-day functioning, both in adolescence and early adulthood. Findings have shown despite the significant sensory-motor deficits displayed by DCD subjects, the impact that this has on day-to-day functioning may be reduced by lifestyle modification.

ROC Curves within the Framework of Neural Network Assembly Memory Model: Some Analytic Results

On the basis of convolutional (Hamming) version of recent Neural Network Assembly Memory Model (NNAMM) for intact two-layer autoassociative Hopfield network optimal receiver operating characteristics (ROCs) have been derived analytically. A method of taking into account explicitly a priori probabilities of alternative hypotheses on the structure of information initiating memory trace retrieval and modified ROCs (mROCs, a posteriori probabilities of correct recall vs. false alarm probability) are introduced. The comparison of empirical and calculated ROCs (or mROCs) demonstrates that they coincide quantitatively and in this way intensities of cues used in appropriate experiments may be estimated. It has been found that basic ROC properties which are one of experimental findings underpinning dual-process models of recognition memory can be explained within our one-factor NNAMM.

Cocrystallisation involving the thioamide, amide and imide functional groups

The work presented in this dissertation focused on the development and characterisation of novel cocrystals that incorporated the thioamide, amide and imide functional groups. A particular emphasis was placed on the characterisation of these cocrystals by single crystal X-ray diffraction methods. In Chapter One a summary of the intermolecular interactions utilised in this work and a short review of the solid state and multicomponent systems is provided. A brief introduction to the ways in which different multicomponent systems can be distinguished, crystal engineering strategies and a number of cocrystal applications highlights the importance the understanding of intermolecular interactions can have on the physical and chemical properties of crystalline materials. Chapter Two is the first Results and Discussion chapter and includes an introduction that is specific to the chapter. The main body of this work focuses on the primary aromatic thioamide functional group and its propensity to cocrystallise with a number of sulfoxides. Unlike the amide functional group, thioamides are not commonly employed in cocrystallisation studies. This chapter presents the first direct comparison between the cocrystallisation abilities of these two functional groups and the intermolecular hydrogen bonding interactions present in the cocrystal structures are examined. Chapter Three describes the crystal landscape of a short series of secondary aromatic amides and their analogous thioamides. Building on the results obtained in Chapter Two, a cocrystal screen of the secondary thioamides with the sulfoxide functional group was carried out in order to determine the effect removing a hydrogen bond had on the supramolecular synthons observed in the cocrystals. These secondary thioamides are also utilised in Chapter Four, which examines their halogen bonding capabilities with two organoiodine coformers: 1,2- and 1,4-diiodotetrafluorobenzene. Chapter Five explores the cocrystallisation abilities of three related cyclic imides as coformers for cocrystallisation with a range of commonly used coformers. Chapter Six is an overall conclusions chapter that highlights the findings of the results presented in Chapters Two to Five. Chapter Seven details the instrument and experimental data for the compounds and cocrystals discussed in the Results and Discussion Chapters. The accompanying CD contains all of the crystallographic data in .cif format for the novel single crystal structures characterised in this work.