Calcium transport by red blood cell membranes from young and adult cattle

Summary It is shown using inside-out membrane vesicles that cattle red cells extrude calcium by means of a calmodulin sensitive Ca-pump whose activity is high in calves and extremely low in adult cows. The deline is not due to loss of calmodulin susceptibility nor to a drop in Ca-affinity.     

Solubilization of human red cell membranes by lysolecithins of various chain lengths

Summary Red cells and membranes prepared from them were treated with graded amounts of palmitoyl, myristoyl and lauroyl lysolecithins. There was no release of phospholipids from the intact red cells in the absence of hemolysis. The solubilization pattern of lipid and protein from the red cell membranes by lysolecithins varies with their chain length.The skillful technical assistance of Mrs Isca Levy is gratefully acknowledged.     

Calcium ion binding to blood cell surfaces

Zusammenfassung Neue Erkenntnisse über die quantitativen Zusammenhänge von fixierten, negativen Ladungen an Zellmembranen und ihren Interaktionen mit Kalzium-Ionen. Die elektrophoretische Analyse der Bindung von Ca-Ionen an menschliche polymorphkernige Leukozyten und rote Blutkörperchen deutet die Anwesenheit von mindestens 3 verschiedenen anionischen Ladungskonfigurationen in der peripheren Zone der Zellen an. Die zwischen den Ca-Ionen und den Oberflächen-Anionen existierenden elektrochemischen freien Bindungsenergien sind relativ schwach; daraus folgert, dass die Ca-Ionen nur schlechte Komponenten für eine direkte interzelluläre überbrückung darstellen.     

Protein transport across and into cell membranes in bacteria and archaea

In the three domains of life, the Sec, YidC/Oxa1, and Tat translocases play important roles in protein translocation across membranes and membrane protein insertion. While extensive studies have been performed on the endoplasmic reticular and Escherichia coli systems, far fewer studies have been done on archaea, other Gram-negative bacteria, and Gram-positive bacteria. Interestingly, work carried out to date has shown that there are differences in the protein transport systems in terms of the number of translocase components and, in some cases, the translocation mechanisms and energy sources that drive translocation. In this review, we will describe the different systems employed to translocate and insert proteins across or into the cytoplasmic membrane of archaea and bacteria.     

Effect of prolactin on human red cell sodium transport

Summary Incubation of red cells with higher concentrations of prolactin in vitro enhanced the cellular sodium level and produced a significant reduction in erythrocyte membrane adenosine triphosphatase activity. This effect was dose and time-dependent. It is the result of an inhibition of the active sodium pump similar to that produced by ouabain, suggesting altered red cell function and electrolyte balance in hyperprolactinemic states.Acknowledgments. Ovine prolactin was generously supplied by Ferring (Malmö, Sweden) and NPA, NIH (Maryland, USA). Thanks are also due to Prof. S. Dutta, Wayne State University, Detroit, for the gift, of ouabain octahydrate and Dr M. Ramachandran and Prof. S. Ramakrishnan, Department of Biochemistry, JIPMER, Pondicherry, for their encouragement and keen interest in this study.     

Effect of prolactin on human red cell sodium transport

Incubation of red cells with higher concentrations of prolactin in vitro enhanced the cellular sodium level and produced a significant reduction in erythrocyte membrane adenosine triphosphatase activity. This effect was dose and time-dependent. It is the result of an inhibition of the active sodium pump similar to that produced by ouabain, suggesting altered red cell function and electrolyte balance in hyperprolactinemic states.     

Of membranes and malaria: phospholipid asymmetry in Plasmodium falciparum-infected red blood cells

Cellular and Molecular Life Sciences - Malaria is a vector-borne parasitic disease with a vast impact on human history, and according to the World Health Organisation, Plasmodium parasites still...     

Biphasic regulation of transport through plant cell membranes by kinetin and its possible relation to directed transport between source and sink

Summary The significance of a biphasic dose-response curve of kinetin for the source-sink relation is shown. Such a regulator can create simultaneously both source and sink.I am indebted to Mrs. Dr.R. Grill for help with the translation of this paper.     

Inversal relationship between basal adenylcyclase activity and maximal degree of stimulation in membranes of red blood cells from rats

Summary The degree of stimulation of adenylcyclase activity, in membranes from immature red blood cells from rats, brought about by isoprenaline, guanylyl-imidodiphosphate and sodium fluoride is strongly dependent on the basal activity of the enzyme. The inversal relationship between basal activity and the maximal degree of stimulation by (–) isoprenaline, shows an apparent seasonal dependence.This work was supported by a grant from the Deutsche Forschungsgemeinschaft.     

Inversal relationship between basal adenylcyclase activity and maximal degree of stimulation in membranes of red blood cells from rats.

The degree of stimulation of adenylcyclase activity, in membranes from immature red blood cells from rats, brought about by isoprenaline, guanylyl-imidodiphosphate and sodium fluoride is strongly dependent on the basal activity of the enzyme. The inversal relationship between basal activity and the maximal degree of stimulation by (--) isoprenaline, shows an apparent seasonal dependence.     

The response to potassium of the Na-K pump ATPase in low-K red blood cells from cattle at birth and in later life

It is shown that in low-K red blood cells of cattle the apparent affinity for K(1/Kapp K) at an inhibitory site of the Na-K ATPase increases markedly during the first 3 months of life. This site probably is the Na accepting site at the internal membrane surface and the change in Kapp K reflects an increase in KNa/KK, the ratio of the true dissociation constants. This effect may explain the concomitant fall in cellular K concentration.     

A fluid drop model of the elliptical red blood cell

Zusammenfassung Der Flächeninhalt der elliptischen Erythrozyten des triploidenTriturus viridescens ist bei gleichbleibender Dicke der Zellen ungefähr 50% grösser als bei diploiden Kontrolltieren. Als Ellipse betrachtet, zeigt die triploide Zelle eine grössere Exzentrizität als die diploide. Im Kontakt mit der Wand eines horizontal gelagerten Zylinders vergrössert sich die Exzentrizität elliptischer Quecksilbertropfen mit zunehmendem Volumen; sie gleichen den Blutkörperchen auch insofern, als ihre Dicke weitgehend konstant bleibt. Diese Beobachtungen unterstützen unsere Ansicht, wonach die endgültige Form der Erythrozyten weitgehend durch die physikalischen Kräfte bestimmt wird, welche während ihrer Reifung in den zylindrischen Blutgefässen, vor allem in den Kapillaren, wirksam sind.     

Separation of catalase and other red cell enzymes from hemoglobin by gel filtration

Zusammenfassung Es wird über ein einfaches Verfahren zur Abtrennung von Katalase und anderer Enzyme aus konzentriertem Haemolysat mit Hilfe der Gel-Filtration unter Verwendung von Sephadex G-100 berichtet.     

Studies of lipid extracts from red blood cells

Zusammenfassung 35 Sera von Patienten mit infektiöser Mononukleose (10 Kranke, 25 Rekonvaleszenten), 15 Sera von Patienten mit anderen Krankheiten und 15 normale Sera wurden im Komplementbindungstest geprüft, wobei als Antigen ein Lipoidextrakt von Rinder-Erythrozyten verwendet wurde. Sera von Rekonvaleszenten nach infektiöser Mononukleose zeigten eine spezifische Komplementbindung, während bei Patienten vor der Rekonvaleszenz die heterophilen Antikörper im Komplementbindungstest nur dann nachgewiesen werden konnten, wenn die Paul-Bunnellsche Reaktion auch positiv ausfiel.     

Changes in red blood cell choline and choline-bound lipids with oral lithium

Summary The influence of oral lithium on the concentration of red blood cell choline (Ch), lecithin, glycerophosphorylcholine (GPCh) and phosphorylcholine (PCh) was studied. The concentration of RBC Ch was significantly elevated and the concentration of lecithin, GPCh and PCh significantly depressed in 16 patients on oral lithium compared to 9 age-matched controls. We conclude that lithium markedly depletes the red blood cell of choline containing compounds including lecithin. These changes may be responsible for both the therapeutic efficacy and the toxicity of lithium.     

Changes in red blood cell choline and choline-bound lipids with oral lithium

The influence of oral lithium on the concentration of red blood cell choline (Ch), lecithin, glycerophosphorylcholine (GPCh) and phosphorylcholine (PCh) was studied. The concentration of RBC Ch was significantly elevated and the concentration of lecithin, GPCh and PCh significantly depressed in 16 patients on oral lithium compared to 9 age-matched controls. We conclude that lithium markedly depletes the red blood cell of choline containing compounds including lecithin. These changes may be responsible for both the therapeutic efficacy and the toxicity of lithium.