7,618 research outputs found

    Altered expression of an ankyrin-repeat protein results in leaf abnormalities, necrotic lesions, and the elaboration of a systemic signal

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    Summary: The PR-like proteins, class I β-1,3-glucanase (GLU I) and chitinase (CHN I), are induced as part of a stereotypic response that can provide protection against viral, bacterial, and fungal pathogens. We have identified two Nicotiana plumbaginifolia ankyrin-repeat proteins, designated G\underline{G} lucanohydrolase B\underline{B} inding P\underline{P} roteins (GBP) 1 and 2, that bind GLU I and CHN I both in vitro and when expressed in yeast cells. Sense as well as antisense transformants of tobacco carrying the GBP1 gene elaborated graft-transmissible acropetally moving signals that induced the downward curling of young leaves. This phenotype was associated with reduced starch, sucrose, and fructose accumulation; the formation of necrotic lesions; and, the induction of markers for the hypersensitive response. GBP1/2 are members of a conserved P\underline{P} lant-specific Ank\underline{Ank} yrin- repeat (PANK) family that includes proteins implicated in carbohydrate allocation, reactive oxygen metabolism, hypersensitive cell death, rapid elicitor responses, virus pathogenesis, and auxin signaling. The similarity in phenotype of PANK transformants and transformants altered in carbohydrate metabolism leads us to propose that PANK family members are multifunctional proteins involved in linking plant defense responses and carbohydrate metabolis

    Molecular docking studies on InhA, MabA and PanK enzymes from Mycobacterium tuberculosis of ellagic acid derivatives from Ludwigia adscendens and Trewia nudiflora

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    There is an urgent need to discover and develop new drugs to combat Mycobacterium tuberculosis, the causative agent of tuberculosis (TB) in humans. In recent years, there has been a renewed interest in the discovery of new anti-TB agents from natural sources. In the present investigation, molecular docking studies were carried out on two ellagic acid derivatives, namely pteleoellagic acid (1) isolated from Ludwigia adscendens, and 3,3′-di-O-methyl ellagic acid 4-O-α-rhamnopyranoside (2) isolated from Trewia nudiflora, to investigate their binding to two enzymes involved in M. tuberculosis cell wall biogenesis, namely 2-trans-enoyl-ACP reductase (InhA) and β-ketoacyl-ACP reductase (MabA), and to pantothenate kinase (PanK type I) involved in the biosynthesis of coenzyme A, essential for the growth of M. tuberculosis. Molecular docking experiments were performed using AutoDock Vina. The crystal structures of InhA, MabA and PanK were retrieved from the RCSB Protein Data Bank (PDB). Isonicotinic-acyl-NADH for InhA and MabA, and triazole inhibitory compound for PanK, were used as references. Pteleoellagic acid showed a high docking score, estimated binding free energy of −9.4 kcal/mol, for the MabA enzyme comparable to the reference compound isonicotinic-acyl-NADH.Knowledge on the molecular interactions of ellagic acid derivatives with essential M. tuberculosis targets could prove a useful tool for the design and development of future anti-TB drugs

    Extracting Leading Indicators of Bank Fragility from Market Prices – Estonia Focus

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    Banking reform has proved to be one of the most problematic elements of economic transition in central and Eastern Europe. Therefore the paper considers the development of the Estonian banking sector and derives individual banks´ fragility scores during transition. To this end we use option-based tools and equity prices to estimate distance-to-default measures of banks´ distress probabilities. Overall, the results suggest that market indicators are moderately useful for anticipating future financial distress and rating changes in transition economies. The implication for an effective supervisory framework is to use a plurality of risk scores when assessing bank vulnerability.banking, financial stability, bank fragility, options, Estonia

    Foreign banks increase the social orientation of Estonian financial sector

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    Reconstruction of Estonian banking system started twenty years ago. Estonia built up for the market economy a banking oriented financial sector, which is centred on commercial banks. During the two decades less than ten banks remained from more than 50 licensed commercial banks, the rest were not able to continue independently, they merged or have failed. The bad result of such kind of development was also the excessive concentration of banking. Banking sector in Estonia during the transition period was opened to the invasion of foreign banks due to the openness of the economy and excessive risks taken. Two banking crises, selected quickly the very limited number of prosperous banks, and the major commercial banks went into the ownership of Scandinavian banks. The qualitative effects of foreign banks’ entry into the Estonian banking market were new features of competition in banking market and transfer of various knowhow from foreign banks. Better liquidity risk management techniques, information systems, credit policy and personnel policy transfer from foreign banks supported banks to have high profitability and low credit losses rates. These directions are noticeable also by quantitative analyses of banking market development. The takeover of main commercial banks by the large Swedish and Finnish banks was one of important factors in the gradual increase of the social orientation of Estonian banks however the ideas of social responsibility of enterprises are especially popular in Scandinavia. In our paper we analyse also Estonian banks’ practices of supporting the social development of Estonia. --

    Assessment of air void content of asphalt using dielectric constant measurements by GPR and with VNA

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    For several years, Ground Penetrating Radar (GPR) has been used in Finland to evaluate the air void content of asphalt pavements. Air void content is an important quality measure of pavement condition for both old and new asphalt pavements. The objective is to investigate if the existing GPR technique and application employed in Finland is sufficiently accurate to be used as a quality control tool in assessing the compaction of newly laid asphalt pavements. The work comprised field and laboratory experiments and a review of the existing PANK calibration method for the GPR measurements. Field experiments were conducted in the summer of 2013 on highways Vt3 and Vt12, near the City of Tampere. The test roads were paved with SMA16 using an approx. 40 mm thick layer of new asphalt. Roads were measured with GPR several times during the fall of 2013. A total of 36 cores and 2 slabs were obtained from the roads and tested in the laboratory with a Vector Network Analyzer. Measurements were done with a 7 to 17 GHz transmission configuration to measure the reference dielectric constant of the asphalt mixture. A major finding is that the PANK calibration method for the GPR inadvertently reduces observed density variations and may introduce a systematic bias. This makes pavements appear to be more homogenous and dense than they actually are according to conventional measurements.Maatutkaa (Ground Penetrating Radar, GPR) on käytetty Suomessa pitkään asfalttipäällysteiden tyhjätilan määrittämiseen. Tyhjätila on tärkeä kriteeri sekä uusien että vanhojen asfalttipäällysteiden laadun selvittämisessä. Tavoitteena on tutkia, onko Suomessa tällä hetkellä käytössä oleva GPR-tekniikka ja sen soveltaminen tarpeeksi tarkkaa uusien asfalttipäällysteiden tiiveyden mittaamiseen. Työ koostui kenttä- ja laboratoriotutkimuksista sekä GPR-mittausten kalibrointiin käytetyn PANK-kalibraatiomallin arvioinnista. Kenttäkokeet suoritettiin kesällä 2013 Tampereen lähellä valtateillä 3 ja 12. Teiden päällyste oli tyyppiä SMA16, ja uuden asfalttikerroksen paksuus oli 40 mm. Tiet mitattiin 1 GHz maatutkalla useita kertoja syksyn 2013 aikana. Teiltä otettiin 36 poranäytettä ja 2 laattanäytettä, jotka testattiin laboratoriossa vektoripiirianalysaattorilla. Asfalttiseoksen dielektrisyysvakio mitattiin 7-17 GHz läpimittauskonfiguraatiolla vertailuarvojen saamiseksi. Tärkein havainto oli se, että PANK-kalibraatiomallin käyttö maatutkamittauksissa vähentää havaittuja tiheyden vaihteluita ja saattaa lisätä systemaattisen virheen mittauksiin. Tämä saa päällysteet näyttämään tasalaatuisemmilta ja tiiviimmiltä kuin mitä ne oikeasti ovat

    Estimating the equilibrium exchange rate of the Estonian kroon

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    The paper presents empirical estimations of the equilibrium exchange rate of the Estonian kroon. The behavioural equilibrium exchange rate (BEER) approach is used to analyse the dynamics of the real effective exchange rate in the time period from 1995 to 2002. The estimates range from a 15% undervaluation to a small overvaluation of the kroon in the beginning of the period and indicate a position close to equilibrium in 2002.equilibrium exchange rate, BEER, cointegration, Estonia