This review of protein dynamics studied by neutron scattering focuses on data collected in the last 10 years. After an introduction to thermal neutron scattering and instrumental aspects, theoretical models that have been used to interpret the data are presented and discussed. Experiments are described according to sample type, protein powders, solutions and membranes. Neutron-scattering results are compared to those obtained from other techniques. The biological relevance of the experimental results is discussed. The major conclusion of the last decade concerns the strong dependence of internal dynamics on the macromolecular environment.

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The European Commission has requested EFSA to assess animal diseases according to the criteria as laid down in Articles 5, 7, 8 and Annex IV for the purpose of categorisation of diseases in accordance with Article 9 of the Regulation (EU) No 2016/429 (Animal Health Law). This scientific opinion addresses the ad hoc method developed for assessing any animal disease for the listing and categorisation of diseases within the Animal Health Law (AHL) framework. The assessment of individual diseases is addressed in distinct scientific opinions that are published separately. The assessment of Articles 5, 8 and 9 criteria is performed on the basis of the information collected according to Article 7 criteria. For that purpose, Article 7 criteria were structured into parameters and the information was collected at parameter level. The resulting fact sheets on the profile and impact of each disease were compiled by disease scientists. A mapping was developed to identify which parameters from Article 7 were needed to inform each Article 5, 8 and 9 criterion. Specifically, for Articles 5 and 9 criteria, a categorical assessment was performed, by applying an expert judgement procedure, based on the mapped information. The judgement was performed by EFSA Panel experts on Animal Health and Welfare in two rounds, individual and collective judgement. The output of the expert judgement on the criteria of Articles 5 and 9 for each disease is composed by the categorical answer, and for the questions where no consensus was reached, the different supporting views are reported.

Fractional power dependence of mean lifetime of electron transfer reaction on viscosity of solvent An ab initio study of specific solvent effects on the electronic coupling element in electron transfer reactions Solvent effects play a major role in controlling electron-transfer reactions. The solvent dynamics happens on a very high-dimensional surface, and this complex landscape is populated by a large number of minima. A critical problem is to understand the conditions under which the solvent dynamics can be represented by a single collective reaction coordinate. When this unidimensional representation is valid, one recovers the successful Marcus theory. In this study the approach used in a previous work V. B. P. Leite and J. N. Onuchic; J. Phys. Chem. 100, 7680 1996 is extended to treat a more realistic solvent model, which includes energy correlation. The dynamics takes place in a smooth and well behaved landscape. The single shell of solvent molecules around a cavity is described by a two-dimensional system with periodic boundary conditions with nearest neighbor interaction. It is shown how the polarization-dependent effects can be inferred. The existence of phase transitions depends on a factor proportional to the contribution from the two parameters of the model. For the present model, suggests the existence of ''weak kinetic phase transitions,'' which are used in the analysis of solvent effects in charge-transfer reactions.

A standard analysis of the scattered neutron incoherent elastic intensity measured with very good energy resolution yields elastic scans, i.e., mean-square displacements of atomic motions (in a pico to nanosecond time scale) in a sample as a function of temperature. This provides a quick way for characterizing the dynamical behavior of biological macromolecules, such behavior being correlated with biological function and activity. Elastic scans of proteins exhibit a dynamical transition at approximately 200 K, marking a cross-over in molecular fluctuations between harmonic and nonharmonic dynamical regimes. This paper presents an approach allowing analysis of the elastic scan in terms of force constants and related parameters, such as the free energy barrier DeltaG at the transition. We find that the increased protein flexibility beyond the dynamical transition is associated with DeltaG approximately equals RT and effective force constants of the order of 0.1-3 N/m. The analysis provides a set of parameters for characterizing molecular resilience and exploring relations among dynamics, function, and activity in proteins.

To identify the mosquito species able to sustain the transmission of West Nile Virus (WNV) in the Camargue region (the main WNV focus of southern France), we assessed the vector competence of Culex modestus and Culex pipiens, the most abundant bird-feeders, and Aedes caspius, the most abundant mammophilic species occasionally found engorged with avian blood. Female mosquitoes were exposed to the infectious meal (10(10.3) plaque forming units (PFU)/mL) by membrane feeding, and hold at 26 degrees C. After the incubation period, disseminated infection was assessed by WNV detection using an indirect fluorescent antibody assay (IFA) on head squashes, and the transmission rate was assessed by the presence of WNV RNA in salivary secretions with a real-time reverse transcriptase-polymerase chain reaction (RT-PCR). After 14 incubation days, the disseminated infection and the transmission rates were 89.2% and 54.5% for Cx. modestus, 38.5% and 15.8% for Cx. pipiens, and 0.8% and 0 for Ae. caspius. Culex modestus was found to be an extremely efficient laboratory WNV vector and could thus be considered the main WNV vector in wetlands of the Camargue. Culex pipiens was a moderately efficient laboratory WNV vector, but in dry areas of the region it could play the main role in WNV transmission between birds and from birds to mammals. Aedes caspius was an inefficient vector of WNV in the laboratory, and despite its high densities, its role in WNV transmission may be minor in southern France.

This paper presents an analytically tractable model that captures the most elementary aspect of the protein folding problem, namely that both the energy and the entropy decrease as a protein folds. In this model, the system diffuses within a sphere in the presence of an attractive spherically symmetric potential. The native state is represented by a small sphere in the center, and the remaining space is identified with unfolded states. The folding temperature, the timedependence of the populations, and the relaxation rate are calculated, and the folding dynamics is analyzed for both golf-course and funnel-like energy landscapes. This simple model allows us to illustrate a surprising number of concepts including entropic barriers, transition states, funnels, and the origin of single exponential relaxation kinetics. Keywords: diffusion; exponential kinetics; free energy barriers; protein foldingProtein folding is a complex chemical reaction in which a polymer interconverts between an ensemble of unfolded states and a compact native configuration. Over the last decade, considerable theoretical and computational effort~Bryngelson et al., 1995;Dill et al., 1995;Fersht, 1995;Karplus & Sali, 1995;Zwanzig, 1995;Orland et al., 1996;Thirumalai & Woodson, 1996;Onuchic et al., 1997;Shakhnovich, 1997;Dobson et al., 1998;Muñoz et al., 1998;Pande et al., 1998! has been devoted to understanding this phenomena on a fundamental level. Much of the conceptual framework that has evolved is based on simple ideas. The purpose of this paper is to illustrate some of these ideas in the context of an exceedingly simple model that can be analytically solved. This model is designed to capture only the most fundamental aspect of the folding problem, namely that both the entropy~i.e., the number of configurations! and the energy decrease as the protein folds.In this model, protein folding is described as diffusion within a closed sphere in the presence of a spherically symmetric potential. The native state is represented by a small spherical region in the center, and the remaining space represents unfolded states. This model is simple enough to yield analytical results, yet it is rich enough to describe many of the features exhibited by more realistic models and even experiments.In the most elementary version of this model, the energy of all unfolded states is zero, but the energy of the native region is so low that it acts as an irreversible trap or "black hole." Mathematically, this means that the surface of the inner~i.e., native! sphere is an absorbing boundary. In the biophysical context, this model has been previously used to analyze how the reduction of spatial dimensionality influences the rate of binding to receptors~Adam & Delbrück, 1968! and to estimate the rate of coalescence of two microdomains during folding~Karplus & Weaver, 1976!. In this paper, this model will be used to illustrate the Levinthal "paradox" Levinthal, 1969! on a golf-course landscape~Bryngelson & Wolynes, 1989!. In three dimensions, when the native regi...

Migratory movements of wild birds likely spread zoonotic infectious agents, such as avian influenza and West Nile viruses.