How simple can a model of an empty viral capsid be? Charge distributions in viral capsids

We investigate and quantify salient features of the charge distributions on viral capsids. Our analysis combines the experimentally determined capsid geometry with simple models for ionization of amino acids, thus yielding the detailed description of spatial distribution for positive and negative charge across the capsid wall. The obtained data is processed in order to extract the mean radii of distributions, surface charge densities and dipole moment densities. The results are evaluated and examined in light of previously proposed models of capsid charge distributions, which are shown to have to some extent limited value when applied to real viruses.Comment: 10 pages, 10 figures; accepted for publication in Journal of Biological Physic

Mechanical and Assembly Units of Viral Capsids Identified via Quasi-Rigid Domain Decomposition

Key steps in a viral life-cycle, such as self-assembly of a protective protein container or in some cases also subsequent maturation events, are governed by the interplay of physico-chemical mechanisms involving various spatial and temporal scales. These salient aspects of a viral life cycle are hence well described and rationalised from a mesoscopic perspective. Accordingly, various experimental and computational efforts have been directed towards identifying the fundamental building blocks that are instrumental for the mechanical response, or constitute the assembly units, of a few specific viral shells. Motivated by these earlier studies we introduce and apply a general and efficient computational scheme for identifying the stable domains of a given viral capsid. The method is based on elastic network models and quasi-rigid domain decomposition. It is first applied to a heterogeneous set of well-characterized viruses (CCMV, MS2, STNV, STMV) for which the known mechanical or assembly domains are correctly identified. The validated method is next applied to other viral particles such as L-A, Pariacoto and polyoma viruses, whose fundamental functional domains are still unknown or debated and for which we formulate verifiable predictions. The numerical code implementing the domain decomposition strategy is made freely available

Quantitative analysis of social grooming behavior of the honey bee Apis mellifera carnica

We observed social grooming behavior in the Carniolan bee, Apis mellifera carnica. Bouts of grooming lasted up to 45 s, and were directed to the wing axis (44.6%), the petiolus (18%) and the sternite regions of abdomen (2.8%) of the receiving bee (41 bees). During grooming, the receiving bees held their wings perpendicular to the body axis. Groomer bees most often cleaned those body parts which could not be reached during self-cleaning by receiving bees. During 18% of the grooming time, groomer bees cleaned their own mouth parts and antennae. The grooming behavior removed dust and pollen from the wing bases and petiolus and realigned the body hairs. No attempts to remove Varroa mites were observed during self-cleaning or social grooming behavior

Compliance of proposed Codex Alimentarius Guidelines for virus management with principles of good practice

Public concerns relating to food safety remain high, with most attention focused on manufactured foods and those served in catering operations. The viral contamination of food can occur anywhere in the food supply chain from farm to fork, but most food-borne viral infections can be traced back to infected persons who handle food that is neither heated nor otherwise treated. Regard to the increasing incidence of food-borne viral infections, the Codex Alimentarius Committee on Food Hygiene issued an international draft on a Code of Hygienic Practice for the control of viruses in foods. Using SWOT analysis as a methodological tool, the main results of the analysis revealed limitations of the document regarding language terminology, detection methodology and transparency

Anti-phospholipid antibodies following vaccination with recombinant hepatitis B vaccine

This study was undertaken to evaluate the possible role of hepatitis B recombinant vaccine inducing the synthesis of IgG and IgM anti-cardiolipin antibodies (aCL), antibodies against β(2)GPI (anti-β(2)GPI), lupus anti-coagulant (LA), anti-nuclear antibodies and antibodies against extractable nuclear antigens (anti-ENA). The study population consisted of 85 healthy students (63 female, 22 male; mean age 20·8 years), vaccinated with three doses of recombinant DNA hepatitis B vaccine. One month after vaccination with the first dose of hepatitis B vaccine a minority of vaccinated individuals showed changes in IgG or IgM aCL or anti-β(2)GPI or LA activity (P < 0·001). Among subjects in whom changes of IgG anti-β(2)GPI were observed, a significantly higher number of increased (8/85) than decreased (2/85) values were found (P < 0·01). Analyses of paired data showed that differences in aCL or anti-β(2)GPI levels before vaccination or 1 month later did not reach statistical significance. In two people aCL transitorily reached medium positivity after the first dose of hepatitis B vaccine with a drop 5 months later. Similar evident anti-β(2)GPI fluctuation was also observed in one person. Another participant was initially low positive for IgG anti-β2GPI and the levels were increasing after vaccination. Two participants became positive for anti-nuclear antibodies during 6 months' follow-up. There were no sex-dependent differences in tested antibodies observed and no associations between levels of aPL and levels of anti-HBV antibodies. We conclude that HBV can induce aPL, although rarely. In genetically susceptible individuals or together with some other triggers such combination might confer the risk of developing a continuous autoimmune response in an individual

Dissociable and Paradoxical Roles of Rat Medial and Lateral Orbitofrontal Cortex in Visual Serial Reversal Learning

Much evidence suggests that reversal learning is mediated by cortico-striatal circuitries with the orbitofrontal cortex (OFC) playing a prominent role. The OFC is a functionally heterogeneous region, but potential differential roles of lateral (lOFC) and medial (mOFC) portions in visual reversal learning have yet to be determined. We investigated the effects of pharmacological inactivation of mOFC and lOFC on a deterministic serial visual reversal learning task for rats. For reference, we also targeted other areas previously implicated in reversal learning: prelimbic (PrL) and infralimbic (IL) prefrontal cortex, and basolateral amygdala (BLA). Inactivating mOFC and lOFC produced opposite effects; lOFC impairing, and mOFC improving, performance in the early, perseverative phase specifically. Additionally, mOFC inactivation enhanced negative feedback sensitivity, while lOFC inactivation diminished feedback sensitivity in general. mOFC and lOFC inactivation also affected novel visual discrimination learning differently; lOFC inactivation paradoxically improved learning, and mOFC inactivation had no effect. We also observed dissociable roles of the OFC and the IL/PrL. Whereas the OFC inactivation affected only perseveration, IL/PrL inactivation improved learning overall. BLA inactivation did not affect perseveration, but improved the late phase of reversal learning. These results support opponent roles of the rodent mOFC and lOFC in deterministic visual reversal learning.</p

BeechCOSTe52 Database

The BeechCOSTe52 includes phenotypic trait measurements from individual trees measured in an international network of provenance tests compiled by the COST Action E52 (2006 – 2010). It comprises 39 trial sites and 217 provenances covering the distribution of European beech (Fagus sylvatica L.). The BeechCOSTe52 database provides individual tree phenotypic measurements of height, diameter at breast height, basal diameter, mortality, spring and autumn leaf phenology

Design of a single-chain polypeptide tetrahedron assembled from coiled-coil segments

Protein structures evolved through a complex interplay of cooperative interactions, and it is still very challenging to design new protein folds de novo. Here we present a strategy to design self-assembling polypeptide nanostructured polyhedra based on mo

Design of a single-chain polypeptide tetrahedron assembled from coiled-coil segments

Protein structures evolved through a complex interplay of cooperative interactions, and it is still very challenging to design new protein folds de novo. Here we present a strategy to design self-assembling polypeptide nanostructured polyhedra based on mo