Rat liver nodules produced by intermittent 2-acetylaminofluorene feed ing exhibit alterations in cell surface receptors reminiscent of impairment of vacuolar acidification. In this report, vacuolar acidification activity, measured as the ATP-dependent quenching of acridine orange, was characterized in liver and nodular membrane fractions using various iontransport inhibitors and with respect to...

The effects of esophageal acidification on airway function are unclear. Some have found that the esophageal acidification causes a small increase in airway resistance, but this change is too small to cause significant symptoms. The aims of this study were to investigate the effects of esophageal acidification on multiple measures of airway function in chloralose-anesthetized cats. The esophagus...

The light-dependent pH changes in the suspending medium of guard cell protoplasts (GCP) from Vicia faba were studied. Upon illumination, the medium was initially slightly alkalinized and then acidified. The extent of alkalinization was lower in CO(2)-free air than in normal air. This initial alkalinization was inhibited by DCMU. Acidification in CO(2)-free air became observable in shorter durat...

High levels of atmospheric carbon dioxide are driving the acidification of the world’s oceans, with considerable and generally negative impacts on the physiology, performance and survival of marine organisms. The differential and often idiosyncratic responses shown by different taxa suggest that interspecific interactions may be drastically affected by ocean acidification. Here, we quantified t...

The natural acidification of groundwater in some types of environment has accelerated by acid atmospheric emissions and cultivation during the last 200 years. The direct effects are seen in changes of the groundwater chemistry in four stages, (1) seasonal depression of pH, alkalinity and some cations in very shallow groundwater, (2) long-term increase of calcium, magnesium, nitrate and sulphate...

Rat liver nodules produced by intermittent 2-acetylaminofluorene feeding exhibit alterations in cell surface receptors reminiscent of impairment of vacuolar acidification. In this report, vacuolar acidification activity, measured as the ATP-dependent quenching of acridine orange, was characterized in liver and nodular membrane fractions using various ion-transport inhibitors and with respect to...

The profound luminal acidification essential for the degradative function of lysosomes requires a counter-ion flux to dissipate an opposing voltage that would prohibit proton accumulation. It has generally been assumed that a parallel anion influx is the main or only counter-ion transport that enables acidification. Indeed, defective anion conductance has been suggested as the mechanism underly...

The best characterized survival mechanism of Mycobacterium tuberculosis inside the macrophage is the inhibition of phagosomal maturation. Phagosomal maturation involves several steps including fusion with lysosomes and acidification. However, it has not been elucidated which components of phagosomal maturation correlate with growth restriction of virulent mycobacteria in human macrophages, and ...

Carbonic anhydrase activity was characterized in freshly dissociated Müller cells of the salamander retina. Intracellular pH was monitored using ratio imaging of the indicator dye BCECF as extracellular PCO2 was varied. The extracellular solution was switched rapidly (141 ms rise time) from a HEPES buffered to a CO2-HCO3- buffered solution (both pH 7.4). Introduction of CO2-HCO3- produced a rap...

[Formula: see text]/NH3fluxes were used to probe apical Na-K-2Cl transport activity of macula densa (MD) cells from rabbit kidney. In the presence of 25 mM NaCl and 5 mM Ba2+, addition of 20 mM[Formula: see text] to the lumen produced a profound intracellular acidification, and ∼80% of the initial acidification rate was bumetanide sensitive. The[Formula: see text]-induced acidification rate was...