Hasil untuk "physics.geo-ph"

C. L. Karr, E. Gentry

T. Clayton, R. Byrne

J. Dressman, R. Berardi, Lambros C. Dermentzoglou et al.

P. Dunfield, R. Knowles, R. Dumont et al.

J. Russell, D. Wilson

Ruminant animals depend on cellulolytic ruminal bacteria to digest cellulose, but these bacteria cannot resist the low ruminal pH that modern feeding practices can create. Because the cellulolytic bacteria cannot grow on cellobiose at low pH, pH sensitivity is a general aspect of growth and not just a limitation of the cellulases per se. Acid-resistant ruminal bacteria have evolved the capacity to let their intracellular pH decrease, maintain a small pH gradient across the cell membrane, and prevent an intracellular accumulation of VFA anions. Cellulolytic bacteria cannot grow with a low intracellular pH, and an increase in pH gradient leads to anion toxicity. Prevotella ruminicola cannot digest native cellulose, but it grows at low pH and degrades the cellulose derivative, carboxymethylcellulose. The Prevotella ruminicola carboxymethylcellulase cannot bind to cellulose, but a recombinant enzyme having the Prevotella ruminicola catalytic domain and a binding domain from Thermomonspora fusca was able to bind and had cellulase activity that was at least 10-fold higher. Based on these results, gene reconstruction offers a means of converting Prevotella ruminicola into a ruminal bacterium that can digest cellulose at low pH.

V. O. Konstantinov, E. A. Baranov, Zhang Fan et al.

Edwin A. Yates, B. Philipp, C. Buckley et al.

Jianzhong Du, Yiqing Tang, A. Lewis et al.

T. Rabilloud, C. Adessi, A. Giraudel et al.

Membrane and nuclear proteins of poor solubility have been separated by high resolution two‐dimensional (2‐D) gel electrophoresis. Isoelectric focusing with immobilized pH gradients leads to severe quantitative losses of proteins in the resulting 2‐D map, although the resolution is usually high. Protein solubility could be improved by using denaturing solutions containing various detergents and chaotropes. Best results were obtained with a denaturing solution containing urea, thiourea, and detergents (both nonionic and zwitterionic). The usefulness of thiourea‐containing denaturing mixtures is shown for microsomal and nuclear proteins as well as for tubulin, a protein highly prone to aggregation.

G. Aad, A. Kupco, P. Laurelli et al.

Rick Orij, J. Postmus, Alexander Ter Beek et al.

C. López-Vázquez, A. Oehmen, C. M. Hooijmans et al.

L. de Nooijer, T. Toyofuku, H. Kitazato

Justin D Brown, Ginger Goekjian, R. Poulson et al.

Jun Chen, Xiaozhong Qiu, Jun Ouyang et al.

Barry P. Young, John J. H. Shin, Rick Orij et al.

K. Talley, E. Alexov

Sunaina Surana, Jaffar M. Bhat, S. Koushika et al.

J. A. Wallace, Jana K. Shen

S. Schreml, R. Meier, O. Wolfbeis et al.