Citrate metabolism in the lactic acid bacterium Leuconostoc mesenteroides generates an electrochemical proton gradient across the membrane by a secondary mechanism (C. Marty-Teysset, C. Posthuma, J. S. Lolkema, P. Schmitt, C. Divies, and W. N. Konings, J. Bacteriol. 178:2178-2185, 1996). Reports on the energetics of citrate metabolism in the related organism Lactococcus lactis are contradictory...

Introduction Since glucose can be converted readily into many useful compounds, efficient conversion of cellulose to this building block is important to successful utilization of biomass for large-scale fuels and chemicals production, The conversion of cellulose to glucose is catalyzed by acid and by glycosidase enzymes. In the general acid catalyzed reaction, it has been shown that the rate of...

To successfully colonize the human gut, enteric bacteria must activate acid resistance systems to survive the extreme acidity (pH 1.5-3.5) of the stomach. The antiporter AdiC is the master orchestrator of the arginine-dependent system. Upon acid shock, it imports extracellular arginine (Arg) into the cytoplasm, providing the substrate for arginine decarboxylases, which consume a cellular proton...

RhoA, RhoB and RhoC GTPases are over 85% identical at the amino acid level, with RhoA and RhoC differing at only one residue (43) across the initial two-thirds of their sequences. A putative regulatory distinction between the molecules is their capacity to be uniquely activated by guanine nucleotide exchange factors (GEFs). We hypothesize that variation of amino acid residue 43 between RhoA/B (...

A simple filtration method is developed to prepare a partially oriented superhydrophobic film of carbon nanotubes (CNTs) that have been catalyzed with uniform small Pt nanoparticles (2.8 nm) at high metal loading (30 wt %). A proton-exchange membrane fuel cell with the oriented CNT film as the cathode achieves higher single-cell performance than those with carbon black and a disordered CNT-film...

Selective Proton Transport In article number 2215109, Tongwen Xu, Liang Ge, Xingya Li, and co-workers report a series of dibenzo-18-crown-6 functionalized sulfonated poly(biphenyl alkylene) membranes. The membranes possess synergistic hydrophilic networks induced by bi-functional sites (crown ether sulfonic-acid group), increasing selective proton transport, providing efficient acid recovery in...

in the current work, graphene oxide (go) samples were prepared at room temperature from graphite flakes using a modified hummer's method to produce metal-free electrocatalysts. the effect of the duration of the oxidation process on the structural, chemical and physical characteristics of the go samples was evaluated using x-ray diffraction (xrd), fourier transform infrared spectroscopy (ftir), ...

We have previously introduced an anisotropic leaky-mode modulator as a waveguide-based, acousto-optic solution for spatial light modulation in holographic video display systems. Waveguide fabrication for these and similar surface acoustic wave devices relies on proton exchange of a lithium niobate substrate, which involves the immersion of the substrate in an acid melt. While simple and effecti...