HDQ (1-hydroxy-2-dodecyl-4(1H)quinolone), a high affinity inhibitor for mitochondrial alternative NADH dehydrogenase

Alternative NADH dehydrogenases (NADH:ubiquinone oxidoreductases) are single subunit respiratory chain enzymes found in plant and fungal mitochondria and in many bacteria. It is unclear how these peripheral membrane proteins interact with their hydrophobic substrate ubiquinone. Known inhibitors of alternative NADH dehydrogenases bind with rather low affinities. We have identified 1-hydroxy-2-dodecyl-4(1H)quinolone as a high affinity inhibitor of alternative NADH dehydrogenase from Yarrowia lipolytica. Using this compound, we have analyzed the bisubstrate and inhibition kinetics for NADH and decylubiquinone. We found that the kinetics of alternative NADH dehydrogenase follow a ping-pong mechanism. This suggests that NADH and the ubiquinone headgroup interact with the same binding pocket in an alternating fashion.

Secondary Transfer Effects of Intergroup Contact: Alternative Accounts and Underlying Processes

Although intergroup contact is one of the most prominent interventions to reduce prejudice. the generalization of contact effects is still a contentious issue This research further examined the rarely studied secondary transfer effect (STE, Pettigrew, 2009) by which contact with a primary outgroup reduces prejudice toward secondary groups that are not directly involved in the contact Across 3 cross-sectional studies conducted in Cyprus (N = 1.653), Northern Ireland (N = 1,973). and Texas (N = 275) and 1 longitudinal study conducted in Northern Ireland (N = 411). the present research sought to systematically rule out alternative accounts of the STE and to investigate 2 potential mediating mechanisms (ingroup reappraisal and attitude generalization) Results indicated that, consistent with the STE. contact with a primary outgroup predicts attitudes toward secondary outgroups. over and above contact with the secondary outgroup, socially desirable responding. and prior attitudes Mediation analyses found strong evidence for attitude generalization but only limited evidence for ingroup reappraisal as an underlying process Two out of 3 tests of a reverse model, where contact with the secondary outgroup predicts attitudes toward the primary outgroup. provide further evidence for an indirect effect through attitude generalization Theoretical and practical implications of these results are discussed, and directions for future research are identified