Molecular epidemiology and evolutionary trajectory of emerging echovirus 30, Europe

In 2018, an upsurge in echovirus 30 (E30) infections was reported in Europe. We conducted a large-scale epidemiologic and evolutionary study of 1,329 E30 strains collected in 22 countries in Europe during 2016-2018. Most E30 cases affected persons 0-4 years of age (29%) and 25-34 years of age (27%). Sequences were divided into 6 genetic clades (G1-G6). Most (53%) sequences belonged to G1, followed by G6 (23%), G2 (17%), G4 (4%), G3 (0.3%), and G5 (0.2%). Each clade encompassed unique individual recombinant forms; G1 and G4 displayed >= 2 unique recombinant forms. Rapid turnover of new clades and recombinant forms occurred over time. Clades G1 and G6 dominated in 2018, suggesting the E30 upsurge was caused by emergence of 2 distinct clades circulating in Europe. Investigation into the mechanisms behind the rapid turnover of E30 is crucial for clarifying the epidemiology and evolution of these enterovirus infections.Molecular basis of virus replication, viral pathogenesis and antiviral strategie

Variation of the Half-Wave Potential of Organic Compounds With pH. Report No. 78

From 19th International Union of Pure and Applied Chemistry Congress, London. A systematic introduction is presented to the subject of the variation with pH of the polarographic half-wave potential, which is probably the most readily measured electrochemical energetic parameter of organic compounds. Emphasis is placed on (a) the types of relationships observed for both reversible and irreversible electrode processes, (b) the mathematical formulation of these relationships, (c) the structural, mechanistic, kinetic, and environmental factors influencing such relationships, and (d) the presumptive physical causes for such relationships, e.g., the effect of pH on the electrochemical kinetics. Although the discussion is primarily concerned with behavior in aqueous solution, the conclusions drawn are equally valid for nonaqueous media in which hydrogen ion or some other Lewis acid can play a significant role. The half-wave potential for an organic electrode process may be independent of pH, or may vary lineanly or sigmoidally; other types of relationships observed are likely to be combinations of such effects. These variations may be due (a) to direct participation of hydrogen ion in the transition state involving the electroactive site in the organic molecule and the electron source, e.g., polarization of the bond to be broken, (b) to control of the state of reactants and/or products via participation in pre- and postequilibria, e.g., acid-base equilibria affecting the nature of the reactant or (c) to the effects of other kinetic, adsorption, steric, hydrogen-bonding and electrical double layer phenomena, as well as to combinations and variations of these effects. Solution composition factors influencing the observed variation of half-wave potential with pH include the ionic strength, the nature of the solvent, the specific identity of buffer components, and nonspecific salt effects. The implications of the experimentally observed half-wave potential-pH relations are considered in respect to the development of analytical procedures and the correlation of half-wave potential data. (auth

Correlation of Polarographic Walf-Wave Potentials With Nuclear Magnetic Resonance "Chemical Shifts." Parallel Correlation With Chemical Reactivity Parameters. Report No. 35

Since nuclear magnetic resonance ''chemical shifts'' are considered to be good measures of electron densities in molecules, the extent to which they can be correlated with the polarographic half-wave potentials of organic compounds has been surveyed. To extend the applicability and interpretation of the proposed correlation, parallel correlatioan of E, with Hammett's sigma and Taft's sigma parameters were made, since both of the latter are also regarded as indication of electronic distrinution at the reactive center. The data in general support the view that changes in half-wave potential with structure are due to both electronic and steric effects, as well as perhaps to adsorption phenomena. Significantly, NMR data obtained with one type of substituent could be correlated with E/sub 1/2 data for a similar type of substituent. New NMR data for aliphatic nitro and halogen compounds are reported. (auth