The Structure and Functions of Hantavirus Nucleocapsid Protein

Hantaviruses, members of the genus Hantavirus in the Bunyaviridae family, are enveloped single-stranded RNA viruses with tri-segmented genome of negative polarity. In humans, hantaviruses cause two diseases, hemorrhagic fever with renal syndrome (HFRS) and hantavirus pulmonary syndrome (HPS), which vary in severity depending on the causative agent. Each hantavirus is carried by a specific rodent host and is transmitted to humans through excreta of infected rodents. The genome of hantaviruses encodes four structural proteins: the nucleocapsid protein (N), the glycoproteins (Gn and Gc), and the polymerase (L) and also the nonstructural protein (NSs). This thesis deals with the functional characterization of hantavirus N protein with regard to its structure. Structural studies of the N protein have progressed slowly and the crystal structure of the whole protein is still not available, therefore biochemical assays coupled with bioinformatical modeling proved essential for studying N protein structure and functions. Presumably, during RNA encapsidation, the N protein first forms intermediate trimers and then oligomers. First, we investigated the role of N-terminal domain in the N protein oligomerization. The results suggested that the N-terminal region of the N protein forms a coiled-coil, in which two antiparallel alpha helices interact via their hydrophobic seams. Hydrophobic residues L4, I11, L18, L25 and V32 in the first helix and L44, V51, L58 and L65 in the second helix were crucial for stabilizing the structure. The results were consistent with the head-to-head, tail-to-tail model for hantavirus N protein trimerization. We demonstrated that an intact coiled-coil structure of the N terminus is crucial for the oligomerization capacity of the N protein. We also added new details to the head-to-head, tail-to-tail model of trimerization by suggesting that the initial step is based on interaction(s) between intact intra-molecular coiled-coils of the monomers. We further analyzed the importance of charged aa residues located within the coiled-coil for the N protein oligomerization. To predict the interacting surfaces of the monomers we used an upgraded in silico model of the coiled-coil domain that was docked into a trimer. Next the predicted target residues were mutated. The results obtained using the mammalian two-hybrid assay suggested that conserved charged aa residues within the coiled-coil make a substantial contribution to the N protein oligomerization. This contribution probably involves the formation of interacting surfaces of the N monomers and also stabilization of the coiled-coil via intramolecular ionic bridging. We proposed that the tips of the coiled-coils are the first to come into direct contact and thus initiate tight packing of the three monomers into a compact structure. This was in agreement with the previous results showing that an increase in ionic strength abolished the interaction between N protein molecules. We also showed that residues having the strongest effect on the N protein oligomerization are not scattered randomly throughout the coiled-coil 3D model structure, but form clusters. Next we found evidence for the hantaviral N protein interaction with the cytoplasmic tail of the glycoprotein Gn. In order to study this interaction we used the GST pull-down assay in combination with mutagenesis technique. The results demonstrated that intact, properly folded zinc fingers of the Gn protein cytoplasmic tail as well as the middle domain of the N protein (that includes aa residues 80 248 and supposedly carries the RNA-binding domain) are essential for the interaction. Since hantaviruses do not have a matrix protein that mediates the packaging of the viral RNA in other negatve stranded viruses (NSRV), hantaviral RNPs should be involved in a direct interaction with the intraviral domains of the envelope-embedded glycoproteins. By showing the N-Gn interaction we provided the evidence for one of the crucial steps in the virus replication at which RNPs are directed to the site of the virus assembly. Finally we started analysis of the N protein RNA-binding region, which is supposedly located in the middle domain of the N protein molecule. We developed a model for the initial step of RNA-binding by the hantaviral N protein. We hypothesized that the hantaviral N protein possesses two secondary structure elements that initiate the RNA encapsidation. The results suggest that amino acid residues (172-176) presumably act as a hook to catch vRNA and that the positively charged interaction surface (aa residues 144-160) enhances the initial N-RNA interacation. In conclusion, we elucidated new functions of hantavirus N protein. Using in silico modeling we predicted the domain structure of the protein and using experimental techniques showed that each domain is responsible for executing certain function(s). We showed that intact N terminal coiled-coil domain is crucial for oligomerization and charged residues located on its surface form a interaction surface for the N monomers. The middle domain is essential for interaction with the cytoplasmic tail of the Gn protein and RNA binding.

An alkaline direct borohydride fuel cell with hydrogen peroxide as oxidant

A novel alkaline direct borohydride fuel cell (ADBFC) using varying concentrations of hydrogen peroxide as oxidant and sodium borohydride with sodium hydroxide, each of differing concentration, as fuel is reported. A peak power density of ca. 150 in W cm(-2) at a cell voltage of 540 mV can be achieved from the optimized ADBFC operating at 70 degrees C. (c) 2004 Elsevier B.V. All rights reserved.

Temperature dependence of g values in tetragonal ionic Cu++ salts

A temperature dependence has been observed in the spin-Hamiltonian parameters of the Cu++ ion in a tetragonal crystal field and the variation has been interpreted in terms of vibronic effects.

Stability of a cylindrical plasma in the presence of a monotonic field-II

The stability of an incompressible inviscid, perfectly conducting cylindrical plasma against azimuthal disturbances in the presence of a monotonic decreasing magnetic field having a constant pitch is discussed by using energy principle. The results obtained by this principle are compared for m = 1 mode (which is a dangerous mode in which there is a lateral shift of the entire column) with that obtained by normal mode analysis. It is found that m = 1 mode is always unstable. Further, an axial line current, external axial field and the surface tension tend to stabilise m ≠ modes.

TOTEM early measurements

The status of the TOTEM experiment is described as well as the prospects for the measurements in the early LHC runs. The primary goal of TOTEM is the measurement of the total p-p cross section, using a method independent of the luminosity. A final accuracy of 1% is ex- pected with dedicated β∗ = 1540 m runs, while at the beginning a 5% resolution is achievable with a β∗ = 90 m optics. Accordingly to the running scenarios TOTEM will be able to measure the elastic scattering in a wide range of t and to study the cross-sections and the topologies of diffractive events. In a later stage, physics studies will be extended to low-x and forward physics collaborating with CMS as a whole experimental apparatus.

Valkoinen läiskä kartalla : Perusvärinnimet ja niiden merkityskentät unkarin- ja suomenkielisissä idiomeissa

Työni tavoitteena on vertailla unkarilaisia ja suomalaisia idiomeja, joissa esiintyy jokin perusvärinnimi. Perusvärinnimiä ovat fehér (valkoinen), fekete (musta), szürke (harmaa), piros tai vörös (punainen), zöld (vihreä), sárga (keltainen), kék (sininen) ja barna (ruskea). Erityisesti pyrin ottamaan selvää käytetäänkö samaa värinnimeä molemmissa kielissä samasta asiasta vai onko värinnimien käytössä tarkasteltujen kielten välillä eroja. Vertailen unkarilaisia idiomeja suomalaisiin ja käytän vertailussa Tamás Forgácsin esittämää mallia ekvivalenssin lajeista. Aineisto on kerätty unkarin- ja suomenkielisistä fraasi- ja idiomisanakirjoista sekä yleissanakirjoista. Idiomi on yksi fraseologismien alaryhmistä. Idiomi koostuu vähintään kahdesta lekseemistä, jotka voidaan kirjoittaa joko yhteen tai erikseen. Idiomi on puhtaimmillaan opaakki, kiteytynyt sanaliitto, mutta idiomi voi olla myös osittain sananmukaisesti tulkittavissa. Idiomaattisuuden ja metaforisuuden aste on jatkumo, jonka toisessa päässä ovat täysin läpinäkymättömät ja toisessa transparentit sanaliitot. Idiomit ovat puhtaimmillaan tiettyyn kieleen sidottuja. Idiomit voivat olla kuitenkin laajalevikkisiä, koska niitä on lainattu eri kieliin suoraan kääntämällä esimerkiksi Raamatusta tai antiikin teksteistä. Viime vuosisatojen ja vuosikymmenten idiomit ovat hypoteettisesti useimmiten käännöslainoja jostain Euroopan valtakielestä. Värinnimitutkimuksen tunnetuimpia teorioita on Berlinin ja Kayn teoria kielessä esiintyvien värinnimien järjestyksestä. Heidän mukaansa musta, valkoinen ja punainen esiintyvät maailman kielissä kaikista yleisimmin, sininen, ruskea ja harmaa puolestaan esiintyvät vain korkeakulttuureissa, eivät esimerkiksi luonnonkansojen kielissä. Hypoteesini on, että aineistossa esiintyvien värinnimien lukumäärä korreloi jossain määrin Berlinin ja Kayn esittämän värinnimien järjestyksen kanssa. Täysin identtisiä idiomeja sanastoltaan ja merkitykseltään löytyy aineistosta suhteellisen paljon, useimmat näistä ovat valkoisen, mustan tai harmaan värin sisältäviä idiomeja. Täysin toisiaan vastaavista idiomeista suurin osa on tullut unkariin ja suomeen Raamatusta tai lainattu sellaisenaan englannista, saksasta tai ranskasta. Osittaisessa vastaavuussuhteessa ja funktionaalisessa vastaavuussuhteessa löytyy värinnimien kannalta mielenkiintoisimmat idiomit: keltainen ja vihreä esiintyvät parissa idiomissa ristikkäin. Pääasiassa idiomeissa esiintyvät värinnimet ovat unkarin ja suomen välillä identtisiä, mikäli unkarilaiselle idiomille löytyy vastine suomen kielestä. Idiomit ilman vastinetta ovat aineiston suurin ja samalla myös kirjavin ryhmä analysoitavaksi, pienin ryhmä puolestaan ovat leksikaalisen vastaavuuden ryhmään kuuluvat idiomit. Suurin osa unkarilaisista idiomeista on työssä analysoitu, mutta suomenkieliset vastineettomat idiomit jäävät vähäiselle huomiolle tutkimusongelman näkökulmasta johtuen. Aineiston 143 unkarilaisesta idiomista noin puolet sijoittuu nollaekvivalenssin eli vastineettomien idiomien ryhmään. Täydellisen ekvivalenssin ryhmä on toiseksi suurin, leksikaalisen vastaavuuden ryhmä pienin. Idiomeissa esiintyvistä väreistä yleisimpiä ovat musta, valkoinen, punainen ja vihreä. Ruskeaa väriä ei esiinny unkarilaisissa idiomeissa lainkaan, suomalaisissa idiomeissa viidessä. Unkarin ja suomen värien merkityskentät vastaavat pitkälti toisiaan. Ainoastaan keltainen ja vihreä esiintyivät selkeästi ristikkäin: unkariksi kateus on keltaista ja suomeksi vihreää, tulokkaaseen liitetään unkarissa vihreä, suomessa keltainen väri.

Steroids and related natural products. VIII. Synthesis of oxasteroids

Peroxydisulfuric acid oxidation of testosterone propionate, progesterone, and cholest-4-en-3-one has been shown to yield 3-oxo-17β-hydroxy-4-oxa-5α-androstane (I, after saponification), 3,20-dioxo-4-oxa-5α-pregnane (V) and 3-oxo-4-oxa-5α-cholestane (VII) respectively. Boron trifluoride etherate-lithium aluminum hydride reduction of δ-lactones I, V, and VII led to the corresponding tetrahydropyran derivatives (IIb, VIa, and VIII). Similar reduction of 3β-hydroxy-17-oxo-17a-oxa-D-homo-5α-androstane (XI) gave 3β-hydroxy-17a-oxa-D-homo-5α-androstane (XIIa). Diborane-boron trifluoride etherate was also found to reduce lactones to cyclic ethers, while reduction with diborane gave hemiacetals. Evidence in support of the structures and stereochemistry assigned to the lactones and their unusual reduction products has been summarized. A tentative mechanism is proposed for lactone → ether reduction employing diborane-boron trifluoride etherate.

The Influence of World Factors on Finnish Stock Market Volatility

This paper investigates to what extent the volatility of Finnish stock portfolios is transmitted through the "world volatility". We operationalize the volatility processes of Finnish leverage, industry, and size portfolio returns by asymmetric GARCH specifications according to Glosten et al. (1993). We use daily return data for January, 2, 1987 to December 30, 1998. We find that the world shock significantly enters the domestic models, and that the impact has increased over time. This applies also for the variance ratios, and the correlations to the world. The larger the firm, the larger is the world impact. The conditional variance is higher during recessions. The asymmetry parameter is surprisingly non-significant, and the leverage hypothesis cannot be verified. The return generating process of the domestic portfolio returns does usually not include the world information set, thus indicating that the returns are generated by a segmented conditional asset pricing model.

Crystal structures and photocatalysis of the triclinic polymorphs of BiNbO4 and BiTaO4

The high-temperature polymorphs of two photocatalytic materials, BiNbO4 and BiTaO4 were synthesized by the ceramic method. The crystal structures of these materials were determined by single-crystal X-ray diffraction. BiNbO4 and BiTaO4 crystallize into the triclinic system P (1) over bar (No. 2), with a = 5.5376(4) angstrom, b = 7.6184(3) angstrom, c = 7.9324(36) angstrom, alpha = 102.565(3)degrees, beta = 90.143(2)degrees, gamma = 92.788 (4)degrees, V = 326.21 (5) angstrom(3). Z = 4 and a = 5.931(1) angstrom, b = 7.672(2) angstrom, c = 7.786(2) angstrom, alpha = 102.94 (3)degrees, beta = 90.04(3)degrees gamma = 93.53(3)degrees, V = 344.59(1) angstrom(3) and Z = 4, respectively. The structures along the c-axis, consist of layers of [Bi2O2] units separated by puckered sheets of (Nb/Ta)O-6 octahedra. Photocatalytic studies on the degradation of dyes indicate selectivity of BiNbO4 towards aromatics containing quinonic and azo functional groups

A new chiral oxazoline derived from camphor and its conversion to (R)-2-methylalkanoic acids

1S,5R,7R)-(-)-10, 10-Dimethyl-3-ethyl-4-oxa--atricyclo[5.2.1.0(1,5)]dec-2-ene 2 was prepared in 95% yield from (1S)-1-amino-2-exo-hydroxyapocamphane 1. The chiral oxazoline could be alkylated (Lhttp://eprints.iisc.ernet.in/cgi/users/home?screen=EPrint::Edit&eprintid=31175&stage=core#tDA/THF/-78 degrees C/RX, RX = ethyl, n-propyl, n-butyl iodides or benzyl bromide) to 3 in 95% yield and > 95% diastereoselectivity, and the products hydrolysed to (R)-2-methylalkanoic acids 4 (43-47% yield, 93-98% e.e.). (C) 2000 Elsevier Science Ltd. All rights reserved.

Prediction of inplane damping from deterministic and stochastic models

This paper reviews computational reliability, computer algebra, stochastic stability and rotating frame turbulence (RFT) in the context of predicting the blade inplane mode stability, a mode which is at best weakly damped. Computational reliability can be built into routine Floquet analysis involving trim analysis and eigenanalysis, and a highly portable special purpose processor restricted to rotorcraft dynamics analysis is found to be more economical than a multipurpose processor. While the RFT effects are dominant in turbulence modeling, the finding that turbulence stabilizes the inplane mode is based on the assumption that turbulence is white noise.

Drained shear strength of fine-grained soil-solid surface interfaces

Herein are reported the results of an investigation on the effective angle of interfacial friction between fine-grained soils and solid surfaces as influenced by the roughness of the material surface, the soil type and the overconsolidation ratio. The ratio of interfacial friction angle to the angle of internal friction (evaluated at constant overconsolidation ratio) of the soil is independent of the overconsolidation ratio. An empirical correlation between this ratio and the roughness of the interface has been proposed.