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The lactate concentration gradient and the components of the electrochemical proton gradient (delta micro H+) were determined in cells of Streptococcus cremoris growing in batch culture. The membrane potential (delta psi) and the pH gradient (delta pH) were determined from the accumulation of the lipophilic cation tetraphenylphosphonium and the weak acid(More)
Streptococcus cremoris was grown in pH-regulated batch and continuous cultures with lactose as the energy source. During growth the magnitude and composition of the electrochemical proton gradient and the lactate concentration gradient were determined. The upper limit of the number of protons translocated with a lactate molecule during lactate excretion(More)
Lactobacillus buchneri ST2A vigorously decarboxylates histidine to the biogenic amine histamine, which is excreted into the medium. Cells grown in the presence of histidine generate both a transmembrane pH gradient, inside alkaline, and an electrical potential (delta psi), inside negative, upon addition of histidine. Studies of the mechanism of histidine(More)
The 'energy-recycling model' [Michels et al. (1979) FEMS Microbiol. Lett. 5, 357-364] postulates the generation of an electrochemical gradient across the bacterial cytoplasmic membrane by carrier-mediated efflux of metabolic endproducts in symport with protons. Experimental evidence for this model is presented. In membrane vesicles from Escherichia coli ML(More)
This paper presents a trial of a species population trend indicator for evaluating progress towards the 2010 biodiversity target in Europe, using existing data. The indicator integrates trends on different species (groups), and can be aggregated across habitats and countries. Thus, the indicator can deliver both headline messages for high-level(More)
ACA-DC 0040 produced an antimicrobial agent, which was named thermophilin T, active against several lactic acid bacteria strains of different species and food spoilage bacteria, such as Clostridium sporogenes C22/10 and Cl. tyrobutyricum NCDO-1754. The crude antimicrobial compound is sensitive to proteolytic enzymes and alpha-amylase, heat-stable (100(More)
In an in vitro demineralization experiment with a plaque of S. mutans C180-2 over enamel, the effect of 0.5 mmol fluoride/L was compared with that of 10 nmol nigericin/L. Since the effects of both substances on the acid production in a dense cell suspension were of the same magnitude, and since nigericin did not affect the enamel solubility, the present(More)
On the basis of the comparison of the nucleotide sequences of the histidine decarboxylase genes (hdcA) of Lactobacillus 30A and Clostridium perfringens and the amino acid sequences of these histidine decarboxylases and those of Lactobacillus buchneri and Micrococcus, oligonucleotides unique to the hdcA genes were synthesized and used in PCR. All(More)
Approximately 1000 lactobacillus strains were isolated and screened for the production of antimicrobial activity, using a target panel of spoilage organisms and pathogens. Only eight positive strains were found; two of these were studied in more detail. Lactobacillus salivarius M7 produces the new broad spectrum bacteriocin salivaricin B which inhibits the(More)