Computer modeling, based on a combination of voltage- and current-clamp data, suggested that an increasing selleckchem density of these channels with distance from the soma, compared with a uniform distribution, would have no significant effect on the general properties of the cell because of their relatively lower expression. Nonetheless, temporal summation of excitatory inputs was affected by the presence of I(h) in the dendrites in a frequency- and distance-dependent fashion. (C) 2009 IBRO. Published by Elsevier Ltd. All rights reserved.”
“BtuB is a beta-barrel membrane protein that facilitates transport of cobalamin (vitamin B12) from the extracellular medium

across the outer membrane of Escherichia coli. it is thought that binding of B12 to BtuB alters the conformation of its periplasm-exposed N-terminal residues (the TonB box), which enables subsequent binding of a TonB protein and leads to eventual uptake of B12 into the cytoplasm. Structural studies determined the location

of the B12 binding site at the top of the BtuB’s beta-barrel, surrounded by extracellular loops. However, the structure of the loops was found to depend on the method used to obtain the protein crystals, PKC412 mouse which-among other factors-differed in calcium concentration. Experimentally, calcium concentration was found to modulate the binding of the B12 substrate to BtuB. In this study, we investigate the effect of calcium ions on the conformation Tariquidar research buy of the extracellular loops of BtuB and their possible role in B12 binding. Using all-atom molecular dynamics, we simulate conformational fluctuations of several X-ray structures of BtuB in the presence and absence of calcium ions. These simulations demonstrate that calcium ions can stabilize the conformation of loops 3-4, 5-6, and 15-16, and thereby prevent occlusion of the binding site. Furthermore, binding of calcium ions to extracellular loops of BtuB was found to enhance correlated motions in the BtuB structure, which is expected to

promote signal transduction. Finally, we characterize conformation dynamics of the TonB box in different X-ray structures and find an interesting correlation between the stability of the TonB box structure and calcium binding.”
“Climate change is predicted to cause higher temperatures and increased precipitation, resulting in increased inflow of nutrients to coastal waters in northern Europe. This has been assumed to increase the overall heterotrophy, including enhanced bacterial growth. However, the relative importance of temperature, resource availability and bacterial community composition for the bacterial growth response is poorly understood. In the present study, we investigated effects of increased temperature on bacterial growth in waters supplemented with different nutrient concentrations and inoculated with microbial communities from distinct seasonal periods. Seven experiments were performed in the northern Baltic Sea spanning an entire annual cycle.