Modulation of renal epithelial ion transport allows organisms to maintain ionic and osmotic homeostasis in the face of varying external conditions. The Drosophila melanogaster Malpighian (renal) tubule offers an unparalleled opportunity to study the molecular mechanisms of epithelial ion transport, due to the powerful genetics of this organism and the accessibility of its renal tubules to physi...

Unidirectional chloride ion jiuxes were measured in the cat ciliary body isolated as a living membrane in vitro. A statistically significant net chloride ion influx (nutrient to secretory) was demonstrated both in the presence of the spontaneous membrane potential and in short-circuited membranes. The isotopically measured net chloride ion influx exceeded the short-circuit current of the membra...

The identification of any enzyme in broken cells as a participant in membrane transport has not been reported. In this paper an enzymatic activity has been so identified through a demonstration that an unusual constellation of characteristics is common to it and to a transport system. Evidence is presented that an adenosine triphosphatase in broken human erythrocyte membranes is a part of the s...

Potassium channels are trans-membrane proteins, which selectively transport K+ ions across cell membranes and play a key role in regulating the physiology of excitability cells and signal transduction pathways. Bothutous Schach (BS) scorpion venom consists of several polypeptides that could modulate ion channels. In this study, the effects of BS crude venom on passive and active electrophysiolo...

Two hypotheses have been proposed recently that offer different views on the role of airway surface liquid (ASL) in lung defense. The "compositional" hypothesis predicts that ASL [NaCl] is kept low (<50 mM) by passive forces to permit antimicrobial factors to act as a chemical defense. The "volume" hypothesis predicts that ASL volume (height) is regulated isotonically by active ion transport to...

Efficient delivery of therapeutic macromolecules and nanomaterials into the nucleus is imperative for gene therapy and nanomedicine. Nucleocytoplasmic molecular transport, however, is tightly regulated by the nuclear pore complex (NPC) with the hydrophobic transport barriers based on phenylalanine and glycine repeats. Herein, we apply scanning electrochemical microscopy (SECM) to quantitatively...

Potassium channels are trans-membrane proteins, which selectively transport K+ ions across cell membranes and play a key role in regulating the physiology of excitability cells and signal transduction pathways. Bothutous Schach (BS) scorpion venom consists of several polypeptides that could modulate ion channels. In this study, the effects of BS crude venom on passive and active electrophysiolo...