Preparation and characterization of inverted cell envelopes of Halobacterium halobium.

Inside-out cell envelopes from Halobacterium halobium R1M1 have been isolated by sonication and subsequent sucrose-density-gradient fractionation. The inverted cell envelopes transport protons from the exterior of the vesicles by a light-dependent, uncoupler-inhibited process. Enzymes usually facing the inside of the cell are exposed to the external medium in this preparation.

Furosemide reduces gastric acid secretion.

Furosemide (10(-3) M) reduced acid secretion of isolated fundic mucosa of the guinea pig by 40%, and lowered the short circuit current, carried mainly by Cl- ions, by 49 +/- 2 (SE) %. These effects occurred within seconds of application of the drug to the serosal side of the mucosa and were fully reversible. When the drug was applied to the mucosal side, the same effects were obtained.

Photoelectric conversion by bacteriorhodopsin in charged synthetic membranes.

Photoelectroactivity of oriented purple membrane layers attached to an ion exchange film has been investigated. The action spectrum of the photocurrent followed the absorption spectrum of bacteriorhodopsin. The intactness of structure and function of bacteriorhodopsin was demonstrated by studies of absorption and photocycle kinetics.

Proton and carbon-13 nuclear magnetic resonance studies of the polar lipids of Halobacterium halobium.

The thermotropic behavior and the dynamic properties of the polar lipids of Halobacterium halobium were studied by 1H and 13C NMR. The studies were performed on three different preparations: micellar solutions in deuterated chloroform, multilamellar dispersions in 2H2O, and unilamellar vesicles obtained from the latter by ultrasonication. Due to the methyl side groups in the alkyl chains of these lipids, the 13C spectra are highly resolved in particular in the micellar solution, allowing peak assignment of the alkyl chain carbons.

Effect of ouabain on electrical conductance of frog skins. Evidence against recycling of sodium.

Ouabain (10(-4) M) added to the serosal solution of isolated frog skin not only stops the active transport of Na+ but causes a dramatic increase in the electric conductance of the skin. The effect also appears when ouabain is added to amiloride-pretreated skins, ruling out the possibility of a cellular effect. The similarity between the effect of ouabain on normal and amiloride-pretreated skins indicates that no appreciable recycling of Na+ across the basolateral membrane of frog skin takes place.

Light-induced conductivity changes in purple membrane suspensions.

Small light-induced changes in the conductivity of light-adapted purple membrane suspended in strong electrolyte solutions were detected. The method used involved modulated light and a phase sensitive detector and it allowed us to detect accurately changes as small as 0.0001% in the conductivity of the suspension.

Interaction of purple membrane with solvents. II. Mode of interaction.

Using the solubility parameter mapping technique (Eisenbach, M., Caplan, S.R.

Interaction of purple membrane with solvents. I. Applicability of solubility parameter mapping.

We carried out spectral studies on the interaction between purple membrane fragments (isolated from Halobacterium halobium) and a series of different solvents, classified quantitatively according to their solubility parameters delta d, delta p, delta h. These represent the contribution of dispersion forces, polar forces, and hydrogen bonding, respectively, to the cohesive energy density of the solvent. Purple membrane fragments, kept in the dark, were suspended in each of the solvents as well as in binary mixtures of solvents, and the spectrum of the resulting suspension was recorded in the wavelength region 250-700 nm.

The use of linear nonequilibrium thermodynamics in the study of renal physiology.

Classical formulations for the analysis of membrane transport processes, which ignored possible interactions between flows of diverse permeant species, often led to inconsistencies in the evaluation of permeability coefficients. For water flow induced by an osmotic pressure difference this difficulty was resolved by Staverman's introduction of the reflection coefficient sigma, a parameter which incorporates the interaction between solute and solvent in the course of their passage through a membrane. A comprehensive nonequilibrium thermodynamic (NET) formalism suitable for many biological systems was provided by Kedem and Katchalsky.

Light-induced pH changes in sub-bacterial particles of Halobacterium halobium. Effects of ionophores.

The kinetics of light-induced acidification and of the subsequent dark-induced alkalization in suspensions of sub-bacterial particles of Halobacterium halobium may be expressed as the sum of two exponentials, indicating two processes (Eisenbach, M., Bakker, E.P.

Measurement of oxygen consumption in voltage-clamped epithelia.

Standard apparatus for in vitro study of anuran epithelia was adapted for the incorporation of Clark oxygen electrodes, permitting the concurrent measurement of electrical current (active sodium transport) and oxygen consumption under voltage-clamp conditions, with independent manipulation of the two bathing solutions. Stability was enhanced by electrical isolation of the O2 electrodes, sensitive temperature control (+/- 0.03 degrees C), and constancy of stirring rate.

Proteolysis and flash photolysis of bacteriorhodopsin in purple membrane fragments.

Pronase treatment of aqueous suspensions of purple membrane fragments from H.halobium leads to the cleavage of bacteriorhodopsin. The protein fragments remaining in the membrane after treatment with relatively small concentrations of enzyme (2% w/w) in normal daylight range in molecular weight from 20,000--21,000 daltons, indicating that cleavage occurs mainly near the extremities of the protein chain.

Supportive granulocyte transfusion in the infected severely neutropenic patient.

The patterns and types of infection in 93 infectious episodes in 76 patients who received supportive granulocyte transfusions are presented. In this population of infected patients 86 per cent had debilitating malignancies, 88 per cent of the infectious episodes were associated with severe (less than 100/microleters) neutropenia and septicemia was documented in 56 per cent. The overall four-week survival was 71 per cent.

Phospholipid substitution of the purple membrane. The stoichiometry of light-induced proton release by phospholipid-substituted purple membranes.

The method of Warren et al. (1974, Proc. Natl.

ABO-incompatible bone marrow transplantation: preparation by plasma exchange and in vivo antibody absorption.

The threat of fatal hemolytic transfusion reaction has been a major deterrent to the use of ABO-incompatible bone marrow donors. An eighteen year old type O male with acute leukemia was prepared to receive type A HLA identical marrow using large volume plasma exchange prior to and following cyclophosphamide administration. Saline agglutinating anti-A antibody was initially present at a titer of 1:128.

Influence of membrane lipids on the photochemistry of bacteriorhodopsin in the purple membrane of Halobacterium halobium.

Purple membrane fragments from Halobacterium halobium were reconstituted with the native lipids replaced by dipalmitoyl phosphatidylcholine and by egg lecithin. In parallel studies the temperature dependence of bacteriorhodopsin phototransient lifetime and absorption dichroism and of in situ lipid microviscosity were determined; the former two by, respectively, conventional and polarization flash photometry, and the latter by observation of emission depolarization of an embedded fluorescent dye, 1,6-diphenyl-1,3,5-hexatriene. Discontinuities in lipid microviscosity profiles in native and egg lecithin purple membrane were reflected in both the photochemical cycle frequency and bacteriorhodopsin chromophore rotational mobility.

Management of chronic myelocytic leukemia in pregnancy by cell pheresis.

Cell pheresis was employed in the initial management of a pregnant patient with chronic myelocytic leukemia (CML). Reduction in circulating leukocyte and platelet counts was evident after two weeks of therapy. This technique is an effective mode of management of the pregnant patient with CML and may play an important therapeutic role in the treatment of other myeloproliferative diseases characterized by dangerously high levels of circulating platelets or myeloblasts.

Bacteriorhodopsin: lipid environment and conformational changes.

The polar lipids of the purple membrane were exchanged for different phosphatidylcholine species. The resulting complexes had the same protein to lipid-phosphorus ratio as the natural membrane, but only about 0.5-1.

Cytotoxins against a granulocyte antigen system: detection by a new method employing cytochalasin-B-treated cells.

A method for demonstrating granulocyte cytotoxins using a modified microdroplet dye exclusion technique and cytochalasin-B-treated cells is described. Cytochalasin-B-treated granulocytes were reacted against 223 sera from multitransfused pregnant and renal transplant patients. Incidence of granulocyte cytotoxins was 11.

Biogenesis of the purple membrane of Halobacterium halobium.

A protein closely resembling the purple membrane protein pre-exists in the cell membrane of H. halobium prior to the appearance of functional bacteriorhodopsin. It is associated with a differentiated membranous structure which has been isolated on a sucrose gradient and appears to be a precursor of the purple membrane.