Two subpopulations of Listeria monocytogenes occur at subinhibitory concentrations of leucocin 4010 and nisin.

In situ analyses of single Listeria monocytogenes cells at subinhibitory concentrations of leucocin 4010 and nisin revealed two subpopulations when measured by fluorescence ratio imaging microscopy (FRIM) after staining with 5(6)-carboxyfluorescein diacetate succinimidyl ester. One subpopulation consisted of cells with a dissipated pH gradient (DeltapH), and the other consisted of cells that maintained DeltapH. The proportion of cells belonging to each subpopulation was estimated, and the concentrations of bacteriocins required to dissipate DeltapH for 90% of the cell population (ED90) was predicted.

Global transcription profiles and intracellular pH regulation measured in Bacillus licheniformis upon external pH upshifts.

For optimization of propagation conditions for an industrially used Bacillus licheniformis, this study examines the effect of transferring cells at the early-stationary growth phase (pH 5.3) to fresh growth medium at pH 5.0-8.

The effect of inoculum age and solid versus liquid propagation on inoculum quality of an industrial Bacillus licheniformis strain.

Shorter lag phases were obtained in cultivations of Bacillus licheniformis using early-compared to late-stationary growth phase inocula and using liquid versus solid propagation medium. Flow cytometry and fluorescence ratio imaging microscopy (FRIM) after staining with 5(6)-carboxyfluorescein diacetate succinimidyl ester (CFDA-SE), confirmed that liquid early-stationary growth phase inoculum had a higher vitality and was more homogeneous than solid late-stationary growth phase inoculum. DNA-microarray analyses indicated that liquid early-stationary growth phase inoculum was in a more active state in terms of cell multiplication whereas solid late-stationary growth phase inoculum was induced to some spore formation potentially causing delayed growth initiation.

Lactic acid tolerance determined by measurement of intracellular pH of single cells of Candida krusei and Saccharomyces cerevisiae isolated from fermented maize dough.

Strains of Candida krusei and Saccharomyces cerevisiae were grown together at 30 degrees C in MYGP broth, pH 2.5, in the presence of 106.4 mM undissociated lactic acid.

The antilisterial effect of Leuconostoc carnosum 4010 and leucocins 4010 in the presence of sodium chloride and sodium nitrite examined in a structured gelatin system.

To further enhance biopreservation of meat products, the antilisterial effect of the newly described protective culture Leuconostoc carnosum 4010 and its bacteriocins, leucocins 4010, was examined in the presence of sodium chloride and sodium nitrite in a solid matrix using a structured gelatin system. Interaction between Listeria monocytogenes 4140 and Leuc. carnosum 4010 or the leucocins 4010-resistant mutant L.