Countercurrent chromatography (CCC) is a generic term covering all forms of liquid–liquid chromatography that use a support-free liquid stationary phase held in place by a simple centrifugal or complex centrifugal force field. Biphasic liquid systems are used with one liquid phase being the stationary phase and the other being the mobile phase. Although initiated almost 30 years ago, CCC lacked...

We consider the Ginzburg-Landau equation for a complex scalar field in one dimension and show that small phase and amplitude perturbations of a stationary solution repair diffusively to converge to a stationary solution. Our methods explain the range of validity of the phase equation, and the coupling between the “fast” amplitude equation and the “slow” phase equation.

The increased expression of the uspA gene of Escherichia coli is an essential part of the cell's response to growth arrest. We demonstrate that stationary-phase activation of the uspA promoter is in part dependent on growth phase-dependent inactivation or repression of the FadR regulator. Transcription of uspA is derepressed during exponential growth in fadR null mutants or by including the fat...

As yeast cultures enter stationary phase in rich, glucose-based medium, differentiation of two major subpopulations of cells, termed quiescent and nonquiescent, is observed. Differences in mRNA abundance between exponentially growing and stationary-phase cultures and quiescent and nonquiescent cells are known, but little was known about protein abundance in these cells. To measure protein abund...

Bacterial persisters are rare phenotypic variants that temporarily tolerate high antibiotic concentrations. Persisters have been hypothesized to underlie the recalcitrance of biofilm infections, and strategies to eliminate these cells have the potential to improve treatment outcomes for many hospital-treated infections. Here we investigate the role of stationary phase metabolism in generation o...

Xanthomonas oryzae pv. oryzae causes bacterial leaf blight, a serious disease of rice. Spontaneous mutants which are deficient for virulence and extracellular polysaccharide (Eps) production accumulate in large numbers in stationary-phase cultures of this bacterium, a phenomenon which we have called stationary-phase variation. A clone (pSD1) carrying the Eps biosynthetic gene (gum) cluster of X...

Cell surface hydrophobicity influences pathogenesis of Candida albicans. Previous studies suggested that stationary-phase hydrophilic and hydrophobic cells, obtained by growth at 37 and 23 degrees C, respectively, may have similar hydrophobic proteins. However, whether hydrophilic and hydrophobic surface proteins differ during the growth cycle at 37 degrees C is unknown. Freeze-fracture analysi...

Metabolomics is a powerful and widely used approach that aims to screen endogenous small molecules (metabolites) of different families present in biological samples. The large variety of compounds to be determined and their wide diversity of physical and chemical properties have promoted the development of different types of hydrophilic interaction liquid chromatography (HILIC) stationary phase...

We are interested in characterizing the process of entry into and the maintenance of the stationary phase. To identify proteins that are induced during growth to stationary phase, we examined protein synthesis in long-term stationary-phase cultures using two-dimensional polyacrylamide gel electrophoresis (2D-PAGE). Although the total rate of protein synthesis declined when growth ceased after t...