Although auxin plays a central role in plant development, little is known about the signal transduction pathways triggered by auxin regulating cell elongation, division and differentiation. We describe the molecular analysis of the mutant tobacco line axi 4/1, which was regenerated from an auxin-independent callus created by activation T-DNA tagging. Transcriptional enhancer-mediated deregulate...

Malpighian tubules of the mealworm Tenebrio molitor were isolated for intracellular measurement of basolateral (V(bl)) and, indirectly, apical (V(ap)) membrane potentials. In control Ringer (50 mmol l(-1) K(+), 140 mmol l(-1) Na(+)), V(bl) was 24 mV, cell negative, and V(ap) was 48 mV, cell negative with reference to the lumen. Ion substitution experiments involving K(+) and Na(+) indicated tha...

The function of the apical Na+-K+-2Cl-cotransporter in mammalian choroid plexus (CP) is uncertain and controversial. To investigate cotransporter function, we developed a novel dissociated rat CP cell preparation in which single, isolated cells maintain normal polarized morphology. Immunofluorescence demonstrated that in isolated cells the Na+-K+-ATPase, Na+-K+-2Cl-cotransporter, and aquaporin ...

The transport of Na+, K+ and Cl- across the isolated epithelium of the eel intestine was studied using a combination of four experimental strategies: short-circuiting, measurements of intracellular potentials and ion concentrations, application of a variety of transport inhibitors and measurement of unidirectional fluxes with radioactive tracers. When short-circuited, the system performs a net ...

1 2 3 4 5 6 7 Kinetics of hyperosmotically-stimulated Na-K-2Cl cotransporter 8 in Xenopus laevis oocytes 9 10 11 12 Eric Delpire and Kenneth B. Gagnon 13 Department of Anesthesiology, Vanderbilt University School of Medicine, 14 Nashville, Tennessee 37232 15 16 17 18 Running title: Na-K-2Cl cotransporter kinetics in frog oocytes. 19 20 21 22 23 24 Address correspondence to: 25 Eric Delpire, 26 ...

Superoxide (O(2)(-)) regulates renal function and is implicated in hypertension. O(2)(-) production increases in response to increased ion delivery in thick ascending limbs (TALs) and macula densa and mechanical strain in other cell types. Tubular flow in the kidney acutely varies causing changes in ion delivery and mechanical stress. We hypothesized that increasing luminal flow stimulates O(2)...

Electroneutral Na(+)-K(+)-2Cl- cotransporters represent one of the major routes for Cl- movement in epithelia. A secretory form of the cotransporter has been described in the basolateral membrane of a variety of epithelia from fish to mammals. We isolated a putative bumetanide-sensitive Na(+)-K(+)-2Cl- cotransporter cDNA, BSC2, from mIMCD-3 cells. Northern analysis indicates that in contrast to...

Furosemide and hydrochlorothiazide (HCTZ) exert their diuretic actions by binding to apical Na(+) transporters, viz., the Na(+)-K(+)-2Cl(-) cotransporter in the thick ascending limb and the Na(+)-Cl(-) cotransporter in the distal convoluted tubule, respectively. We carried out semiquantitative immunoblotting and immunohistochemistry of rat kidneys to investigate whether chronic administration o...

We previously reported that the bumetanide-sensitive Na(+)-K(+)-2Cl- cotransporter (NKCC1) is involved in the hepatic Na+ and K+ sensor mechanism. In the present study, we examined the effects of a high-NaCl or high-KCl diet on hepatic Na+ and K+ receptor sensitivity and NKCC1 expression in the liver of Sprague-Dawley rats. RT-PCR and Western blots were used to measure NKCC1 mRNA and protein ex...