Chlorite dismutase (CD) catalyzes the disproportionation of chlorite to chloride (ClO(2)(-)-->Cl(-)+O(2)) and is present in bacteria capable of cell respiration using perchlorate or chlorate. The activity of this enzyme has previously been measured by monitoring oxygen evolution using a Clark-type dissolved oxygen (DO) probe. We demonstrate here, using two other methods to measure CD activity (...

Tracer chloride and potassium net efflux from valinomycin-treated human erythrocytes were measured into media of different chloride concentrations, Clo, at 25 degrees C and pH 7.8. Net efflux was maximal [45-50 mmol (kg cell solids)-1 min-1] at Clo = 0. It decreased hyperbolically with increasing Clo to 14-16 mmol (kg cell solids)-1 min-1. Half-maximal inhibition occurred at Clo = 3 mM. In the ...

Chloride exit across the apical membranes of secretory epithelial cells is acutely regulated by the cAMP-mediated second messenger cascade. To better understand the regulation of transepithelial chloride secretion, we have characterized the complement of cAMP-dependent protein kinase (PKA) isoforms present in the human colonic epithelial cell line T84. Our results show that both type I and type...

The effects of aldosterone on sodium transport and chloride permeability were investigated by electrophysiology in two structurally distinct epithelial used as models for the distal renal tubule: the A6 cell monolayer as compared with the amphibian skin epithelium (ASE). Short-circuit current (Isc) and transepithelial conductance (Gt) were measured in A6 monolayers incubated overnight with(out)...

Mechanisms regulating the red cell pH in lamprey (Lampetra fluviatilis) were studied using the ammonium chloride prepulse technique. The cells were initially incubated in a physiological saline containing 20 mmol l-1 ammonium chloride, and intracellular pH measured with the DMO technique. Ammonium chloride was then rapidly removed by centrifugation, and the changes in the intracellular pH follo...

Degenerative histopathalogical alterations were seen in liver due to chronic exposure of the fish, Labeo rohita to chlorides of chromium, nickel and zinc for 30 days. However, more severe degenerative changes were observed in case of zinc chloride exposed fish than nickel chloride and chromium chloride treated fishes, indicating more toxic nature of zinc chloride. There were enlarged nuclei, co...

Human malignant gliomas are highly invasive tumors. Mechanisms that allow glioma cells to disseminate, migrating through the narrow extracellular brain spaces are poorly understood. We recently demonstrated expression of large voltage-dependent chloride (Cl(-)) currents, selectively expressed by human glioma cells in vitro and in situ (Ullrich et al., 1998). Currents are sensitive to several Cl...

The distribution and rates of exchange of the ions sodium, potassium, and chloride in single internodal cells of the ecorticate characean, Nitdlopsis obtusa, have been studied. In tracer experiments three kinetic compartments were found, the outermost "free space" of the cell, a compartment we have called "protoplasmic non4ree space", and the cell sap. The concentrations in the vacuole were 54 ...

The hindgut of the desert locust possesses an unusual chloride transport system. The isolated locust rectum absorbs chloride from the mucosal (lumen) to the serosal (haemolymph) side at a rate which is equal to the short-circuit current (Isc). Net chloride transport (JClnet) persists in nominally Na-free or HCO3(CO2)-free saline, is insensitive to normal inhibitors of NaCl co-transport and anio...

Debaryomyces hanseniZopf isolated from the fructoplane of apples were found to be effective as biocontrol agent against rot of papaya caused by Ulocladium. chartarum(Pr.) Simm. The ability of D. hansenii to prevent infection of U. chartarum was lost when the antagonist cells were killed by autoclaving. Cell free culture filtrates of antagonist were unable to prevent disease incidence. Efficacy ...