Improved purification of pyruvate decarboxylase from wheat germ. Its partial characterisation and comparison with the yeast enzyme

An improved procedure was developed for the isolation of pyruvate decarboxylase from wheat germ. Its final step, an electrophoresis of the native apoenzyme in concave pore gradient polyacrylamide gels, followed by superficial activity-staining, produced two bands of different molecular masses and chain compositions. The high-molecular-mass band occurred in low quantity and consisted of, probably eight, apparently identical chains of Mr = 33,000, as judged from sodium dodecyl sulfate electrophoreses. The low-molecular-mass band contained two types of chains with Mr alpha = 63,000-65,000 and Mr beta = 61,000-62,000. The N termini of both chains were threonine, whereas their C-terminal sequences were different: alpha, -(Val)-(Ser)-(Ala)-Leu; beta, -(His)-(Asp)-(Ala)-Ser. Their amino acid composition was too different to be compatible with our original concept of one chain being produced from the other by proteolytic shortening. Limited proteolysis by Staphylococcus aureus V8 proteinase yielded peptides partly identical size and partly quite different. In all properties investigated, the low-molecular-mass enzyme largely resembled yeast pyruvate decarboxylase; the holoenzyme appeared to possess (alpha beta)2 structure, the apoenzyme alpha beta. SH reagents inactivated the enzyme. Binding and fluorescence of 2-p-toluidinonaphthalene-6-sulfonate indicated a similar lipophilicity of the active site as found earlier for the yeast enzyme. 2-Hydroxy-5-nitrobenzyl modification of exposed tryptophan residues left the holoenzyme intact, but in the apoenzyme it destroyed most of the cofactor-binding ability and hence the activity. The strength of cofactor binding and the maximal specific activity were found somewhat lower than in yeast pyruvate decarboxylase.     

Bayesian Phylogeography of Crimean-Congo Hemorrhagic Fever Virus in Europe

Crimean-Congo hemorrhagic fever (CCHF) is a zoonosis mainly transmitted by ticks that causes severe hemorrhagic fever and has a mortality rate of 5-60%. The first outbreak of CCHF occurred in the Crimean peninsula in 1944-45 and it has recently emerged in the Balkans and eastern Mediterranean. In order to reconstruct the origin and pathway of the worldwide dispersion of the virus at global and regional (eastern European) level, we investigated the phylogeography of the infection by analysing 121 publicly available CCHFV S gene sequences including two recently characterised Albanian isolates. The spatial and temporal phylogeny was reconstructed using a Bayesian Markov chain Monte Carlo approach, which estimated a mean evolutionary rate of 2.96 x 10^-4 (95%HPD=1.6 and 4.7 x 10^-4) substitutions/site/year for the analysed fragment. All of the isolates segregated into seven highly significant clades that correspond to the known geographical clades: in particular the two new isolates from northern Albania clustered significantly within the Europe 1 clade. Our phylogeographical reconstruction suggests that the global CCHFV clades originated about one thousand years ago from a common ancestor probably located in Africa. The virus then spread to Asia in the XV century and entered Europe on at least two occasions: the first in the early 1800s, when a still circulating but less or non-pathogenic virus emerged in Greece and Turkey, and the second in the early 1900s, when a pathogenic CCHFV strain began to spread in eastern Europe. The most probable location for the origin of this European clade 1 was Russia, but Turkey played a central role in spreading the virus throughout Europe. Given the close proximity of the infected areas, our data suggest that the movement of wild and domestic ungulates from endemic areas was probably the main cause of the dissemination of the virus in eastern Europe.     

Proteins from bovine tissues and biological fluids: defining a reference electrophoresis map for liver,kidney, muscle,plasma and red blood cells

A number of high resolution two-dimensional electrophoresis (2-DE) reference maps for bovine tissues and biological fluids have been determined for animals in basal state. Among the 1863 distinct protein features detected in samples of liver, kidney, muscle, plasma and red blood cells, 509 species were identified and associated to 209 different genes. Difficulties in the identification were related to the poorly characterized Bos taurus genome and were solved by a combined matrix-assisted laser desorption/ionisation-mass spectrometry and liquid chromatography-electrospray ionization tandem mass spectrometry approach. The experimental output allowed us to establish a 2-DE database accessible through the World Wide Web network at the URL address (http://www.iabbam.na.cnr.it/Biochem). These reference maps may serve as a tool in future veterinary medical studies aimed at the evaluation of changes in protein repertoire for altered animal physiological conditions and infectious diseases, to the definition of molecular markers for novel diagnostic kits and vaccines, as well as the characterization of protein modifications in bovine materials following technological processes used in the food industry.     

Reconstruction of the Evolutionary Dynamics of A(H3N2) Influenza Viruses Circulating in Italy from 2004 to 2012

Background

Influenza A viruses are characterised by their rapid evolution, and the appearance of point mutations in the viral hemagglutinin (HA) domain causes seasonal epidemics. The A(H3N2) virus has higher mutation rate than the A(H1N1) virus. The aim of this study was to reconstruct the evolutionary dynamics of the A(H3N2) viruses circulating in Italy between 2004 and 2012 in the light of the forces driving viral evolution.

Methods

Phylodinamic analyses were made using a Bayesian method, and codon-specific positive selection acting on the HA coding sequence was evaluated.

Results

Global and local phylogenetic analyses showed that the Italian strains collected between 2004 and 2012 grouped into five significant Italian clades that included viral sequences circulating in different epidemic seasons. The time of the most recent common ancestor (tMRCA) of the tree root was between May and December 2003. The tMRCA estimates of the major clades suggest that the origin of a new viral strain precedes the effective circulation of the strain in the Italian population by 6–31 months, thus supporting a central role of global migration in seeding the epidemics in Italy. The study of selection pressure showed that four codons were under positive selection, three of which were located in antigenic sites. Analysis of population dynamics showed the alternation of periods of exponential growth followed by a decrease in the effective number of infections corresponding to epidemic and inter-epidemic seasons.

Conclusions

Our analyses suggest that a complex interaction between the immune status of the population, migrations, and a few selective sweeps drive the influenza A(H3N2) virus evolution. Our findings suggest the possibility of the year-round survival of local strains even in temperate zones, a hypothesis that warrants further investigation.     

New aspects of ICD therapy: from rhythm therapy to complex cardiac monitoring. Development of an implantable, ICD-assisted, intrathoracic 6-channel ECG for continuous monitoring of high infarct risk patients]

Implantable defibrillator systems (ICD) are therapy of choice for the treatment of life-threatening ventricular arrhythmias and in prevention of sudden cardiac death. In more than 80% of patients who receive an ICD, the underlying cardiac disease is a coronary heart disease. Since arrhythmogenic sudden cardiac death can be reliably prevented in these patients by the use of ICD technology, the cardiac prognosis for these patients is determined by the occurrence of myocardial ischemia and myocardial infarction, as well as from the heart failure which develops in consequence. An intrathoracic 6-channel ECG comparable to the standard surface ECG can be reconstructed by further technical development of the electrode configurations currently present in ICD systems. The importance of this development in early diagnosis of myocardial ischemias and myocardial infarction can hardly be adequately estimated at the moment. The chronic consequences of myocardial infarction can be completely prevented or at least greatly reduced by means of such diagnostics and inclusion of immediate initiation of effective, appropriate early therapeutic measures before more serious symptoms even occur. In the development and pilot studies thus far, it has been found that the intrathoracic 6-channel ECG which can be generated in the ICD is capable of reliably recognizing acute myocardial ischemia, irrespective of localization or extent earlier and better than the standard surface ECG. Continuous preventive ischemia monitoring using the implanted ICD thus appears possible in patients at risk of infarction.     

Eine einfache Methode zur Isolierung der „Membran-Grundsubstanz” grampositiver und gramnegativer Baketerien

Zusammenfassung Nach Extraktion von grampositiven und gramnegativen Bakterien in 1 n NaOH verbleibt ein schleimiges Sediment, das nach phasenkontrast-und elektronenmikroskopischen Untersuchungen aus leeren Membranen besteht. Die Hydrolyse in 6 n NaOH und anschließende papierchromatographische Trennung zeigt als Hauptbestandteile der Membranen Glutaminsäure, Alanin und ,-Diaminopimelinsäure bzw. Lysin. Außerdem sind in den alkaliunlöslichen Membranen noch größere Mengen Kohlenhydrate enthalten. Es wird darauf hingewiesen, daß durch die gute Alkalibeständigkeit der Grundsubstanz der Bakterienmembran eine einfache Methode gegeben ist, auch von geringen Bakterienmengen die Grundsubstanz relativ rein zu gewinnen. Bei Benützung der Aminosäurezusammensetzung der Grundsubstanz als Bestimmungsmerkmal für die taxonomische Einordnung der Bakterien dürfte diese Methode von Vorteil sein.     

Genetic diversity of Usutu virus

Usutu virus is a mosquito-borne virus first isolated from Culex naevei in South Africa in 1959. The first emergence of Usutu virus outside Africa was recorded in Austria. Here, a phylogenetic analysis targeting the E5 and NS5 genes was carried out on the viral strains circulating in Europe. The NS5 gene tree showed two main clades, one of which included the Italian sequences. In the E gene tree all sequences grouped into the same main clade, with sequences from Austria divided into two separate clusters. Only sites under negative selective pressure were found in E and NS5 proteins. The results suggest that Usutu virus circulating in Europe has a degree of genetic diversity higher than expected and that infection may arise from different sources.     

Pharmacogenomics of anesthetic drugs in transgenic LQT1 and LQT2 rabbits reveal genotype-specific differential effects on cardiac repolarization

Anesthetic agents prolong cardiac repolarization by blocking ion currents. However, the clinical relevance of this blockade in subjects with reduced repolarization reserve is unknown. We have generated transgenic long QT syndromes type 1 (LQT1) and type 2 (LQT2) rabbits that lack slow delayed rectifier K+ currents (IKs) or rapidly activating K+ currents (IKr) and used them as a model system to detect the channel-blocking properties of anesthetic agents. Therefore, LQT1, LQT2, and littermate control (LMC) rabbits were administered isoflurane, thiopental, midazolam, propofol, or ketamine, and surface ECGs were analyzed. Genotype-specific heart rate correction formulas were used to determine the expected QT interval at a given heart rate. The QT index (QTi) was calculated as percentage of the observed QT/expected QT. Isoflurane, a drug that blocks IKs) prolonged the QTi only in LQT2 and LMC but not in LQT1 rabbits. Midazolam, which blocks inward rectifier K+ current (IK1), prolonged the QTi in both LQT1 and LQT2 but not in LMC. Thiopental, which blocks both IKs and IK1, increased the QTi in LQT2 and LMC more than in LQT1. By contrast, ketamine, which does not block IKr, IKs, or IK1, did not alter the QTi in any group. Finally, anesthesia with isoflurane or propofol resulted in lethal polymorphic ventricular tachycardia (pVT) in three out of nine LQT2 rabbits. Transgenic LQT1 and LQT2 rabbits could serve as an in vivo model in which to examine the pharmacogenomics of drug-induced QT prolongation of anesthetic agents and their proarrhythmic potential. Transgenic LQT2 rabbits developed pVT under isoflurane and propofol, underlining the proarrhythmic risk of IKs blockers in subjects with reduced IKr.