Functional split and crosslinking of the membrane domain of the β subunit of proton-translocating transhydrogenase from Escherichia coli

Proton pumping nicotinamide nucleotide transhydrogenase from Escherichia coli contains an α subunit with the NAD(H)-binding domain I and a β subunit with the NADP(H)-binding domain III. The membrane domain (domain II) harbors the proton channel and is made up of the hydrophobic parts of the α and β subunits. The interface in domain II between the α and the β subunits has previously been investigated by cross-linking loops connecting the four transmembrane helices in the α subunit and loops connecting the nine transmembrane helices in the β subunit. However, to investigate the organization of the nine transmembrane helices in the β subunit, a split was introduced by creating a stop codon in the loop connecting transmembrane helices 9 and 10 by a single mutagenesis step, utilizing an existing downstream start codon. The resulting enzyme was composed of the wild-type α subunit and the two new peptides β1 and β2. As compared to other split membrane proteins, the new transhydrogenase was remarkably active and catalyzed activities for the reduction of 3-acetylpyridine-NAD + by NADPH, the cyclic reduction of 3-acetylpyridine-NAD + by NADH (mediated by bound NADP(H)), and proton pumping, amounting to about 50-107% of the corresponding wild-type activities. These high activities suggest that the α subunit was normally folded, followed by a concerted folding of β1 + β2. Cross-linking of a βS105C-βS237C double cysteine mutant in the functional split cysteine-free background, followed by SDS-PAGE analysis, showed that helices 9, 13, and 14 were in close proximity. This is the first time that cross-linking between helices in the same β subunit has been demonstrated.

Caffeine, cognition, and persuasion:evidence for caffeine increasing the systematic processing of persuasive messages

Caffeine is known to increase arousal, attention, and information processing–all factors implicated in facilitating persuasion. In a standard attitude-change paradigm, participants consumed an orange-juice drink that either contained caffeine (3.5 mg/kg body weight) or did not (placebo) prior to reading a counterattitudinal communication (anti-voluntary euthanasia). Participants then completed a thought-listing task and a number of attitude scales. The first experiment showed that those who consumed caffeine showed greater agreement with the communication (direct attitude: voluntary euthanasia) and on an issue related to, but not contained in, the communication (indirect attitude: abortion). The order in which direct and indirect attitudes were measured did not affect the results. A second experiment manipulated the quality of the arguments in the message (strong vs. weak) to determine whether systematic processing had occurred. There was evidence that systematic processing occurred in both drink conditions, but was greater for those who had consumed caffeine. In both experiments, the amount of message-congruent thinking mediated persuasion. These results show that caffeine can increase the extent to which people systematically process and arc influenced by a persuasive communication.

Ethnicities and values in a changing world

Recent debates about national identity, belonging and community cohesion can appear to suggest that ethnicity is a static entity and that ethnic difference is a source of conflict in itself. "Ethnicities and Values in a Changing World" presents an alternative account of ethnicity and calls into question models of community cohesion that present ethnicity as the source of antagonisms and differences that must be overcome. It suggests instead that ethnicity is itself multiple and changing and is unlikely to be a basis for articulating shared values. This volume brings together an international team of leading scholars in the field of ethnic studies in order to examine innovative articulations of ethnicity and challenge the contention that ethnicity is static or that it necessarily represents traditional values and cultures. Asserting that ethnicity is deployed in part as an expression of values and a model of ethical practice, this book examines displays of ethnicity as assertions of identity and statements about way of life, sense of entitlement and manner of connection to others. "Ethnicities and Values in a Changing World" draws together debates about the articulation of ethnic identity, the nature of our relation to each other and discussions of everyday ethics, thus engaging with discussions of racism, multiculturalism and community cohesion. As such, it will appeal not only to sociologists, but to anyone working in the fields of cultural studies, race and ethnicity, globalization, migration and anthropology. Table of Contents: Introduction: ethnicities, values and old-fashioned racism, Gargi Bhattacharyya; Teaching race and racism in the 21st century: thematic considerations, Howard Winant; Diaspora conversations: ethics, ethicality, work and life; Migrant women's networking: new articulations of transnational ethnicity, Ronit Lentin; 'The people do what the political class isn't able to do': antigypsyism, ethnicity denial and the politics of racism without racism, Robbie McVeigh; Violent urban protest - identities, ethics and Islamism, Max Farrar; Beliefs, boundaries and belonging: African Pentecostals in Ireland, Abel Ugba; On being a 'good' refugee, John Gabriel and Jenny Harding; Narrating lived experience in a binational community in Costa Rica, Carlos Sandoval Garcia; Conclusion: ethnicity and ethicality in an unequal world, Gargi Bhattacharyya; Index.

Measurement of key compositional parameters in two species of energy grass by Fourier transform infrared spectroscopy

Two energy grass species, switch grass, a North American tuft grass, and reed canary grass, a European native, are likely to be important sources of biomass in Western Europe for the production of biorenewable energy. Matching chemical composition to conversion efficiency is a primary goal for improvement programmes and for determining the quality of biomass feed-stocks prior to use and there is a need for methods which allow cost effective characterisation of chemical composition at high rates of sample through-put. In this paper we demonstrate that nitrogen content and alkali index, parameters greatly influencing thermal conversion efficiency, can be accurately predicted in dried samples of these species grown under a range of agronomic conditions by partial least square regression of Fourier transform infrared spectra (R2 values for plots of predicted vs. measured values of 0.938 and 0.937, respectively). We also discuss the prediction of carbon and ash content in these samples and the application of infrared based predictive methods for the breeding improvement of energy grasses.