The effect of pediocin JD, a bacteriocin produced by Pediococcus acidilactici JD1-23, on the proton motive force and proton permeability of resting whole cells of Listeria monocytogenes Scott A was determined. Control cells, treated with trypsin-inactivated bacteriocin at a pH of 5.3 to 6.1, maintained a pH gradient and a membrane potential of approximately 0.65 pH unit and 75 mV, respectively....

This new method for fractionation of serum alkaline phosphatase isoenzymes is based on isoelectric focusing on a mixed-type polyacrylamide support containing an immobilized pH gradient with a superimposed carrier-ampholyte gradient. All known forms of alkaline phosphatase are separated in an Immobiline pH 3.5-6.0 gradient, the sample being applied into pockets cast on a pH 8.0 plateau. Sharp zy...

The influence of membrane pH gradients on the transbilayer distribution of some common phospholipids has been investigated. We demonstrate that the transbilayer equilibrium of the acidic phospholipids egg phosphatidylglycerol (EPG) and egg phosphatidic acid (EPA) can be manipulated by membrane proton gradients, whereas phosphatidylethanolamine, a zwitterionic phospholipid, remains equally distr...

The internal pH of lung lamellar bodies was investigated with membrane permeable basic amines. Isolated granular pneumocytes and isolated lung lamellar bodies exhibited fluorescence when exposed to 8 microM quinacrine, suggesting accumulation of this dye due to an acidic internal pH. Uptake of [14C]methylamine by isolated lung lamellar bodies was measured to quantitate the intralamellar body pH...

1. Mammalian erythrocytes swell as the pH of the isotonic suspending medium is lowered, as a direct consequence of the specialized permeability properties of the erythrocyte membrane. Lymphocytes and granulocytes from a variety of sources did not exhibit this property. 2. The behaviour of mouse bone marrow erythroid cells at various stages of differentiation was studied by using a change in buo...

BACKGROUND The serotonin system has repeatedly been associated with the pathogenesis of pulmonary hypertension (PH). OBJECTIVE To comparatively analyze plasmatic and intrathrombocytic serotonin levels in arterial and mixed venous blood of patients with PH and unaffected controls to elucidate pulmonary serotonin metabolisms. PATIENTS AND METHODS Catheters were placed in the radial and pulmon...

Strains of oral streptococci maintain an intracellular pH (pHi) that is more alkaline than the external pH (pHo). The delta pH (pHi-pHo) was about 0.6 in neutral media and about 0.9 in media of pH 5.5. Addition of 10 micrograms of F- per ml at pH 7.0 reduced the delta pH in Streptococcus salivarius to 0.17. The reduction of delta pH in S. sanguis H7PR3 was less pronounced, whereas the delta pH ...

It is now almost 30 years since Heatley' first published his mathematical model of the mucus barrier to acid-pepsin attack. At that time, techniques were not available to evaluate the components of his model and the existence of a pH gradient across mucus gel, sustaining the cell surface at near neutral pH despite luminal acid, could not be confirmed. During the last decade advances in technolo...