Expression and phosphorylation of the Na+-Cl- cotransporter NCC in vivo is regulated by dietary salt, potassium, and SGK1.

PubMed

Vallon, Volker; Schroth, Jana; Lang, Florian; Kuhl, Dietmar; Uchida, Shinichi

2009-09-01

The Na-Cl cotransporter NCC is expressed in the distal convoluted tubule, activated by phosphorylation, and has been implicated in renal NaCl and K(+) homeostasis. The serum and glucocorticoid inducible kinase 1 (SGK1) contributes to renal NaCl retention and K(+) excretion, at least in part, by stimulating the epithelial Na(+) channel and Na(+)-K(+)-ATPase in the downstream segments of aldosterone-sensitive Na(+)/K(+) exchange. In this study we confirmed in wild-type mice (WT) that dietary NaCl restriction increases renal NCC expression and its phosphorylation at Thr(53), Thr(58), and Ser(71), respectively. This response, however, was attenuated in mice lacking SGK1 (Sgk1(-/-)), which may contribute to impaired NaCl retention in those mice. Total renal NCC expression and phosphorylation at Thr(53), Thr(58), and Ser(71) in WT were greater under low- compared with high-K(+) diet. This finding is consistent with a regulation of NCC to modulate Na(+) delivery to downstream segments of Na(+)/K(+) exchange, thereby modulating K(+) excretion. Dietary K(+)-dependent variation in renal expression of total NCC and phosphorylated NCC were not attenuated in Sgk1(-/-) mice. In fact, high-K(+) diet-induced NCC suppression was enhanced in Sgk1(-/-) mice. The hyperkalemia induced in Sgk1(-/-) mice by a high-K(+) diet may have augmented NCC suppression, thereby increasing Na(+) delivery and facilitating K(+) excretion in downstream segments of impaired Na(+)/K(+) exchange. In summary, changes in NaCl and K(+) intake altered NCC expression and phosphorylation, an observation consistent with a role of NCC in NaCl and K(+) homeostasis. The two maneuvers dissociated plasma aldosterone levels from NCC expression and phosphorylation, implicating additional regulators. Regulation of NCC expression and phosphorylation by dietary NaCl restriction appears to involve SGK1.

Protein Phosphatase 1 Inhibitor-1 Deficiency Reduces Phosphorylation of Renal NaCl Cotransporter and Causes Arterial Hypotension

PubMed Central

Picard, Nicolas; Trompf, Katja; Yang, Chao-Ling; Miller, R. Lance; Carrel, Monique; Loffing-Cueni, Dominique; Fenton, Robert A.; Ellison, David H.

2014-01-01

The thiazide-sensitive NaCl cotransporter (NCC) of the renal distal convoluted tubule (DCT) controls ion homeostasis and arterial BP. Loss-of-function mutations of NCC cause renal salt wasting with arterial hypotension (Gitelman syndrome). Conversely, mutations in the NCC-regulating WNK kinases or kelch-like 3 protein cause familial hyperkalemic hypertension. Here, we performed automated sorting of mouse DCTs and microarray analysis for comprehensive identification of novel DCT-enriched gene products, which may potentially regulate DCT and NCC function. This approach identified protein phosphatase 1 inhibitor-1 (I-1) as a DCT-enriched transcript, and immunohistochemistry revealed I-1 expression in mouse and human DCTs and thick ascending limbs. In heterologous expression systems, coexpression of NCC with I-1 increased thiazide-dependent Na+ uptake, whereas RNAi-mediated knockdown of endogenous I-1 reduced NCC phosphorylation. Likewise, levels of phosphorylated NCC decreased by approximately 50% in I-1 (I-1−/−) knockout mice without changes in total NCC expression. The abundance and phosphorylation of other renal sodium-transporting proteins, including NaPi-IIa, NKCC2, and ENaC, did not change, although the abundance of pendrin increased in these mice. The abundance, phosphorylation, and subcellular localization of SPAK were similar in wild-type (WT) and I-1−/− mice. Compared with WT mice, I-1−/− mice exhibited significantly lower arterial BP but did not display other metabolic features of NCC dysregulation. Thus, I-1 is a DCT-enriched gene product that controls arterial BP, possibly through regulation of NCC activity. PMID:24231659

Deficiency of electroneutral K+-Cl- cotransporter 3 causes a disruption in impulse propagation along peripheral nerves.

PubMed

Sun, Yuan-Ting; Lin, Thy-Sheng; Tzeng, Shun-Fen; Delpire, Eric; Shen, Meng-Ru

2010-10-01

Nerve conduction requires the fine tuning of ionic currents through delicate interactions between axons and Schwann cells. The K(+)-Cl(-) cotransporter (KCC) family includes four isoforms (KCC1-4) that play an important role in the maintenance of cellular osmotic homeostasis via the coupled electroneutral movement of K(+) and Cl(-) with concurrent water flux. Mutation in SLC12A6 gene encoding KCC3 results in an autosomal recessive disease, known as agenesis of the corpus callosum associated with peripheral neuropathy. Nevertheless, the role of KCC3 in nerve function remains a puzzle. In this study, the microscopic examination of KCC isoforms expressed in peripheral nerves showed high expression of KCC2-4 in nodal segments of the axons and in the perinucleus and microvilli of Schwann cells. The KCC inhibitor [[(dihydroindenyl)oxy]alkanoic acid] but not the Na(+)-K(+)-2Cl(-)-cotransport inhibitor (bumetanide) dose-dependently suppressed the amplitude and area of compound muscle action potential, indicating the involvement of KCC activity in peripheral nerve conduction. Furthermore, the amplitude and area under the curve were smaller, and the nerve conduction velocity was slower in nerves from KCC3(-/-) mice than in nerves from wild-type mice, while the expression pattern of KCC2 and KCC4 was similar in KCC3 kockout and wild-type strains. KCC3(-/-) mice also manifested a prominent motor deficit in the beam-walking test. This is the first study to demonstrate that the K(+)-Cl(-) cotransporter activity of KCC3 contributes to the propagation of action potentials along peripheral nerves. (c) 2010 Wiley-Liss, Inc.

Molecular cloning and biochemical characterization of two cation chloride cotransporter subfamily members of Hydra vulgaris.

PubMed

Hartmann, Anna-Maria; Pisella, Lucie I; Medina, Igor; Nothwang, Hans Gerd

2017-01-01

Cation Chloride Cotransporters (CCCs) comprise secondary active membrane proteins mainly mediating the symport of cations (Na+, K+) coupled with chloride (Cl-). They are divided into K+-Cl- outward transporters (KCCs), the Na+-K+-Cl- (NKCCs) and Na+-Cl- (NCCs) inward transporters, the cation chloride cotransporter interacting protein CIP1, and the polyamine transporter CCC9. KCCs and N(K)CCs are established in the genome since eukaryotes and metazoans, respectively. Most of the physiological and functional data were obtained from vertebrate species. To get insights into the basal functional properties of KCCs and N(K)CCs in the metazoan lineage, we cloned and characterized KCC and N(K)CC from the cnidarian Hydra vulgaris. HvKCC is composed of 1,032 amino-acid residues. Functional analyses revealed that hvKCC mediates a Na+-independent, Cl- and K+ (Tl+)-dependent cotransport. The classification of hvKCC as a functional K-Cl cotransporter is furthermore supported by phylogenetic analyses and a similar structural organization. Interestingly, recently obtained physiological analyses indicate a role of cnidarian KCCs in hyposmotic volume regulation of nematocytes. HvN(K)CC is composed of 965 amino-acid residues. Phylogenetic analyses and structural organization suggest that hvN(K)CC is a member of the N(K)CC subfamily. However, no inorganic ion cotransport function could be detected using different buffer conditions. Thus, hvN(K)CC is a N(K)CC subfamily member without a detectable inorganic ion cotransporter function. Taken together, the data identify two non-bilaterian solute carrier 12 (SLC12) gene family members, thereby paving the way for a better understanding of the evolutionary paths of this important cotransporter family.

Internal magnesium, 2,3-diphosphoglycerate, and the regulation of the steady-state volume of human red blood cells by the Na/K/2Cl cotransport system

PubMed Central

1992-01-01

This study is concerned with the relationship between the Na/K/Cl cotransport system and the steady-state volume (MCV) of red blood cells. Cotransport rate was determined in unfractionated and density- separated red cells of different MCV from different donors to see whether cotransport differences contribute to the difference in the distribution of MCVs. Cotransport, studied in cells at their original MCVs, was determined as the bumetanide (10 microM)-sensitive 22Na efflux in the presence of ouabain (50 microM) after adjusting cellular Na (Nai) and Ki to achieve near maximal transport rates. This condition was chosen to rule out MCV-related differences in Nai and Ki that might contribute to differences in the net chemical driving force for cotransport. We found that in both unfractionated and density-separated red cells the cotransport rate was inversely correlated with MCV. MCV was correlated directly with red cell 2,3-diphosphoglycerate (DPG), whereas total red cell Mg was only slightly elevated in cells with high MCV. Thus intracellular free Mg (Mgifree) is evidently lower in red cells with high 2,3-DPG (i.e., high MCV) and vice versa. Results from flux measurements at their original MCVs, after altering Mgifree with the ionophore A23187, indicated a high Mgi sensitivity of cotransport: depletion of Mgifree inhibited and an elevation of Mgifree increased the cotransport rate. The apparent K0.5 for Mgifree was approximately 0.4 mM. Maximizing Mgifree at optimum Nai and Ki minimized the differences in cotransport rates among the different donors. It is concluded that the relative cotransport rate is regulated for cells in the steady state at their original cell volume, not by the number of copies of the cotransporter but by differences in Mgifree. The interindividual differences in Mgifree, determined primarily by differences in the 2,3-DPG content, are responsible for the differences in the relative cotransport activity that results in an inverse relationship

Phosphorylation and transport in the Na-K-2Cl cotransporters, NKCC1 and NKCC2A, compared in HEK-293 cells.

PubMed

Hannemann, Anke; Flatman, Peter W

2011-03-25

Na-K-2Cl cotransporters help determine cell composition and volume. NKCC1 is widely distributed whilst NKCC2 is only found in the kidney where it plays a vital role reabsorbing 20% of filtered NaCl. NKCC2 regulation is poorly understood because of its restricted distribution and difficulties with its expression in mammalian cell cultures. Here we compare phosphorylation of the N-termini of the cotransporters, measured with phospho-specific antibodies, with bumetanide-sensitive transport of K(+) ((86)Rb(+)) (activity) in HEK-293 cells stably expressing fNKCC1 or fNKCC2A which were cloned from ferret kidney. Activities of transfected transporters were distinguished from those of endogenous ones by working at 37 °C. fNKCC1 and fNKCC2A activities were highest after pre-incubation of cells in hypotonic low-[Cl(-)] media to reduce cell [Cl(-)] and volume during flux measurement. Phosphorylation of both transporters more than doubled. Pre-incubation with ouabain also strongly stimulated fNKCC1 and fNKCC2A and substantially increased phosphorylation, whereas pre-incubation in Na(+)-free media maximally stimulated fNKCC1 and doubled its phosphorylation, but inhibited fNKCC2A, with a small increase in its phosphorylation. Kinase inhibitors halved phosphorylation and activity of both transporters whereas inhibition of phosphatases with calyculin A strongly increased phosphorylation of both transporters but only slightly stimulated fNKCC1 and inhibited fNCCC2A. Thus kinase inhibition reduced phosphorylation and transport, and transport stimulation was only seen when phosphorylation increased, but transport did not always increase with phosphorylation. This suggests phosphorylation of the N-termini determines the transporters' potential capacity to move ions, but final activity also depends on other factors. Transport cannot be reliably inferred solely using phospho-specific antibodies on whole-cell lysates.

Revisiting the NaCl cotransporter regulation by with-no-lysine kinases

PubMed Central

Bazúa-Valenti, Silvana

2015-01-01

The renal thiazide-sensitive Na+-Cl− cotransporter (NCC) is the salt transporter in the distal convoluted tubule. Its activity is fundamental for defining blood pressure levels. Decreased NCC activity is associated with salt-remediable arterial hypotension with hypokalemia (Gitelman disease), while increased activity results in salt-sensitive arterial hypertension with hyperkalemia (pseudohypoaldosteronism type II; PHAII). The discovery of four different genes causing PHAII revealed a complex multiprotein system that regulates the activity of NCC. Two genes encode for with-no-lysine (K) kinases WNK1 and WNK4, while two encode for kelch-like 3 (KLHL3) and cullin 3 (CUL3) proteins that form a RING type E3 ubiquitin ligase complex. Extensive research has shown that WNK1 and WNK4 are the targets for the KLHL3-CUL3 complex and that WNKs modulate the activity of NCC by means of intermediary Ste20-type kinases known as SPAK or OSR1. The understanding of the effect of WNKs on NCC is a complex issue, but recent evidence discussed in this review suggests that we could be reaching the end of the dark ages regarding this matter. PMID:25788573

Elevated FGF23 Levels in Mice Lacking the Thiazide-Sensitive NaCl cotransporter (NCC).

PubMed

Pathare, Ganesh; Anderegg, Manuel; Albano, Giuseppe; Lang, Florian; Fuster, Daniel G

2018-02-26

Fibroblast growth factor 23 (FGF23) participates in the orchestration of mineral metabolism by inducing phosphaturia and decreasing the production of 1,25(OH) 2 D 3 . It is known that FGF23 release is stimulated by aldosterone and extracellular volume depletion. To characterize this effect further in a model of mild hypovolemia, we studied mice lacking the thiazide sensitive NaCl cotransporter (NCC). Our data indicate that NCC knockout mice (KO) have significantly higher FGF23, PTH and aldosterone concentrations than corresponding wild type (WT) mice. However, 1,25(OH) 2 D 3 , fractional phosphate excretion and renal brush border expression of the sodium/phosphate co-transporter 2a were not different between the two genotypes. In addition, renal expression of FGF23 receptor FGFR1 and the co-receptor Klotho were unaltered in NCC KO mice. FGF23 transcript was increased in the bone of NCC KO mice compared to WT mice, but treatment of primary murine osteoblasts with the NCC inhibitor hydrochlorothiazide did not elicit an increase of FGF23 transcription. In contrast, the mineralocorticoid receptor blocker eplerenone reversed excess FGF23 levels in KO mice but not in WT mice, indicating that FGF23 upregulation in NCC KO mice is primarily aldosterone-mediated. Together, our data reveal that lack of renal NCC causes an aldosterone-mediated upregulation of circulating FGF23.

Urine concentrating mechanism: impact of vascular and tubular architecture and a proposed descending limb urea-Na+ cotransporter.

PubMed

Layton, Anita T; Dantzler, William H; Pannabecker, Thomas L

2012-03-01

We extended a region-based mathematical model of the renal medulla of the rat kidney, previously developed by us, to represent new anatomic findings on the vascular architecture in the rat inner medulla (IM). In the outer medulla (OM), tubules and vessels are organized around tightly packed vascular bundles; in the IM, the organization is centered around collecting duct clusters. In particular, the model represents the separation of descending vasa recta from the descending limbs of loops of Henle, and the model represents a papillary segment of the descending thin limb that is water impermeable and highly urea permeable. Model results suggest that, despite the compartmentalization of IM blood flow, IM interstitial fluid composition is substantially more homogeneous compared with OM. We used the model to study medullary blood flow in antidiuresis and the effects of vascular countercurrent exchange. We also hypothesize that the terminal aquaporin-1 null segment of the long descending thin limbs may express a urea-Na(+) or urea-Cl(-) cotransporter. As urea diffuses from the urea-rich papillary interstitium into the descending thin limb luminal fluid, NaCl is secreted via the cotransporter against its concentration gradient. That NaCl is then reabsorbed near the loop bend, raising the interstitial fluid osmolality and promoting water reabsorption from the IM collecting ducts. Indeed, the model predicts that the presence of the urea-Na(+) or urea- Cl(-) cotransporter facilitates the cycling of NaCl within the IM and yields a loop-bend fluid composition consistent with experimental data.

The Thiazide-sensitive NaCl Cotransporter Is Targeted for Chaperone-dependent Endoplasmic Reticulum-associated Degradation*

PubMed Central

Needham, Patrick G.; Mikoluk, Kasia; Dhakarwal, Pradeep; Khadem, Shaheen; Snyder, Avin C.; Subramanya, Arohan R.; Brodsky, Jeffrey L.

2011-01-01

The thiazide-sensitive NaCl cotransporter (NCC, SLC12A3) mediates salt reabsorption in the distal nephron of the kidney and is the target of thiazide diuretics, which are commonly prescribed to treat hypertension. Mutations in NCC also give rise to Gitelman syndrome, a hereditary salt-wasting disorder thought in most cases to arise from impaired NCC biogenesis through enhanced endoplasmic reticulum-associated degradation (ERAD). Because the machinery that mediates NCC quality control is completely undefined, we employed yeast as a model heterologous expression system to identify factors involved in NCC degradation. We confirmed that NCC was a bona fide ERAD substrate in yeast, as the majority of NCC polypeptide was integrated into ER membranes, and its turnover rate was sensitive to proteasome inhibition. NCC degradation was primarily dependent on the ER membrane-associated E3 ubiquitin ligase Hrd1. Whereas several ER luminal chaperones were dispensable for NCC ERAD, NCC ubiquitination and degradation required the activity of Ssa1, a cytoplasmic Hsp70 chaperone. Compatible findings were observed when NCC was expressed in mammalian kidney cells, as the cotransporter was polyubiquitinated and degraded by the proteasome, and mammalian cytoplasmic Hsp70 (Hsp72) coexpression stimulated the degradation of newly synthesized NCC. Hsp70 also preferentially associated with the ER-localized NCC glycosylated species, indicating that cytoplasmic Hsp70 plays a critical role in selecting immature forms of NCC for ERAD. Together, these results provide the first survey of components involved in the ERAD of a mammalian SLC12 cation chloride cotransporter and provide a framework for future studies on NCC ER quality control. PMID:22027832

The Effect of WNK4 on the Na+-Cl- Cotransporter Is Modulated by Intracellular Chloride.

PubMed

Bazúa-Valenti, Silvana; Chávez-Canales, María; Rojas-Vega, Lorena; González-Rodríguez, Xochiquetzal; Vázquez, Norma; Rodríguez-Gama, Alejandro; Argaiz, Eduardo R; Melo, Zesergio; Plata, Consuelo; Ellison, David H; García-Valdés, Jesús; Hadchouel, Juliette; Gamba, Gerardo

2015-08-01

It is widely recognized that the phenotype of familial hyperkalemic hypertension is mainly a consequence of increased activity of the renal Na(+)-Cl(-) cotransporter (NCC) because of altered regulation by with no-lysine-kinase 1 (WNK1) or WNK4. The effect of WNK4 on NCC, however, has been controversial because both inhibition and activation have been reported. It has been recently shown that the long isoform of WNK1 (L-WNK1) is a chloride-sensitive kinase activated by a low Cl(-) concentration. Therefore, we hypothesized that WNK4 effects on NCC could be modulated by intracellular chloride concentration ([Cl(-)]i), and we tested this hypothesis in oocytes injected with NCC cRNA with or without WNK4 cRNA. At baseline in oocytes, [Cl(-)]i was near 50 mM, autophosphorylation of WNK4 was undetectable, and NCC activity was either decreased or unaffected by WNK4. A reduction of [Cl(-)]i, either by low chloride hypotonic stress or coinjection of oocytes with the solute carrier family 26 (anion exchanger)-member 9 (SLC26A9) cRNA, promoted WNK4 autophosphorylation and increased NCC-dependent Na(+) transport in a WNK4-dependent manner. Substitution of the leucine with phenylalanine at residue 322 of WNK4, homologous to the chloride-binding pocket in L-WNK1, converted WNK4 into a constitutively autophosphorylated kinase that activated NCC, even without chloride depletion. Elimination of the catalytic activity (D321A or D321K-K186D) or the autophosphorylation site (S335A) in mutant WNK4-L322F abrogated the positive effect on NCC. These observations suggest that WNK4 can exert differential effects on NCC, depending on the intracellular chloride concentration. Copyright © 2015 by the American Society of Nephrology.

Circadian exosomal expression of renal thiazide-sensitive NaCl cotransporter (NCC) and prostasin in healthy individuals.

PubMed

Castagna, Annalisa; Pizzolo, Francesca; Chiecchi, Laura; Morandini, Francesca; Channavajjhala, Sarath Kiran; Guarini, Patrizia; Salvagno, Gianluca; Olivieri, Oliviero

2015-06-01

A circadian timing system is involved in the maintenance of fluid and electrolyte balance and blood pressure control. Aldosterone and vasopressin modulate ion transporters and channels crucial in sodium (Na) and water reabsorption such as the epithelium Na channel and the renal thiazide-sensitive NaCl cotransporter (NCC). We analyzed in urinary exosomes the intraday variations of NCC and prostasin expression and the association with electrolytes and water balance parameters. Blood and urine samples were collected at five time points during the day from five healthy subjects. Blood renin, aldosterone, cortisol, ACTH, and plasmatic and urinary Na, potassium, creatinine, adiuretin (ADH), NCC, and prostasin were evaluated. ACTH and cortisol showed a circadian pattern, similarly to aldosterone, while exosomal NCC and prostasin pattern were similar to urinary ADH, decreased in the morning and subsequently increased in the afternoon and evening. In urinary exosomes, NCC and prostasin had a diurnal pattern parallel to ADH and aquaporin 2, confirming that, in healthy subjects, both prostasin and NCC relate to water balance. These results provide suggestions for a possible chronotherapeutic approach in patients treated with thiazides, diuretic drugs acting as specific inhibitors of NCC-mediated Na reabsorption. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Osmoregulation Requires Brain Expression of the Renal Na-K-2Cl Cotransporter NKCC2

PubMed Central

Konopacka, Agnieszka; Qiu, Jing; Yao, Song T.; Greenwood, Michael P.; Greenwood, Mingkwan; Lancaster, Thomas; Inoue, Wataru; de Souza Mecawi, Andre; Vechiato, Fernanda M.V.; de Lima, Juliana B.M.; Coletti, Ricardo; Hoe, See Ziau; Martin, Andrew; Lee, Justina; Joseph, Marina; Hindmarch, Charles; Paton, Julian; Antunes-Rodrigues, Jose; Bains, Jaideep

2015-01-01

The Na-K-2Cl cotransporter 2 (NKCC2) was thought to be kidney specific. Here we show expression in the brain hypothalamo-neurohypophyseal system (HNS), wherein upregulation follows osmotic stress. The HNS controls osmotic stability through the synthesis and release of the neuropeptide hormone, arginine vasopressin (AVP). AVP travels through the bloodstream to the kidney, where it promotes water conservation. Knockdown of HNS NKCC2 elicited profound effects on fluid balance following ingestion of a high-salt solution—rats produced significantly more urine, concomitant with increases in fluid intake and plasma osmolality. Since NKCC2 is the molecular target of the loop diuretics bumetanide and furosemide, we asked about their effects on HNS function following disturbed water balance. Dehydration-evoked GABA-mediated excitation of AVP neurons was reversed by bumetanide, and furosemide blocked AVP release, both in vivo and in hypothalamic explants. Thus, NKCC2-dependent brain mechanisms that regulate osmotic stability are disrupted by loop diuretics in rats. PMID:25834041

K-Cl cotransport function and its potential contribution to cardiovascular disease.

PubMed

Adragna, Norma C; Lauf, Peter K

2007-12-01

K-Cl cotransport is the coupled electroneutral movement of K and Cl ions carried out by at least four protein isoforms, KCC1-4. These transporters belong to the SLC12A family of coupled cotransporters and, due to their multiple functions, play an important role in the maintenance of cellular homeostasis. Significant information exists on the overall function of these transporters, but less is known about the role of the specific isoforms. Most functional studies were done on K-Cl cotransport fluxes without knowing the molecular details, and only recently attention has been paid to the isoforms and their individual contribution to the fluxes. This review summarizes briefly and updates the information on the overall functions of this transporter, and offers some ideas on its potential contribution to the pathophysiological basis of cardiovascular disease. By virtue of its properties and the cellular ionic distribution, K-Cl cotransport participates in volume regulation of the nucleated and some enucleated cells studied thus far. One of the hallmarks in cardiovascular disease is the inability of the organism to maintain water and electrolyte balance in effectors and/or target tissues. Oxidative stress is another compounding factor in cardiovascular disease and of great significance in our modern life styles. Several functions of the transporter are modulated by oxidative stress, which in turn may cause the transporter to operate in either "overdrive" with the purpose to counteract homeostatic changes, or not to respond at all, again setting the stage for pathological changes leading to cardiovascular disease. Intracellular Mg, a second messenger, acts as an inhibitor of K-Cl cotransport and plays a crucial role in regulating the activity of protein kinases and phosphatases, which, in turn, regulate a myriad of cellular functions. Although the role of Mg in cardiovascular disease has been dealt with for several decades, this chapter is evolving nowadays at a faster

Prolactin regulates transcription of the ion uptake Na+/Cl- cotransporter (ncc) gene in zebrafish gill

USGS Publications Warehouse

Breves, Jason P.; Serizier, Sandy B.; Goffin, Vincent; McCormick, Stephen D.; Karlstrom, Rolf O.

2013-01-01

Prolactin (PRL) is a well-known regulator of ion and water transport within osmoregulatory tissues across vertebrate species, yet how PRL acts on some of its target tissues remains poorly understood. Using zebrafish as a model, we show that ionocytes in the gill directly respond to systemic PRL to regulate mechanisms of ion uptake. Ion-poor conditions led to increases in the expression of PRL receptor (prlra), Na+/Cl− cotransporter (ncc; slc12a10.2), Na+/H+ exchanger (nhe3b; slc9a3.2), and epithelial Ca2+ channel (ecac; trpv6) transcripts within the gill. Intraperitoneal injection of ovine PRL (oPRL) increased ncc and prlra transcripts, but did not affect nhe3b or ecac. Consistent with direct PRL action in the gill, addition of oPRL to cultured gill filaments stimulated ncc in a concentration-dependent manner, an effect blocked by a pure human PRL receptor antagonist (Δ1-9-G129R-hPRL). These results suggest that PRL signaling through PRL receptors in the gill regulates the expression of ncc, thereby linking this pituitary hormone with an effector of Cl− uptake in zebrafish for the first time.

Cloning, characterization, and chromosomal mapping of a human electroneutral Na(+)-driven Cl-HCO3 exchanger.

PubMed

Grichtchenko, I I; Choi, I; Zhong, X; Bray-Ward, P; Russell, J M; Boron, W F

2001-03-16

The electroneutral Na(+)-driven Cl-HCO3 exchanger is a key mechanism for regulating intracellular pH (pH(i)) in neurons, glia, and other cells. Here we report the cloning, tissue distribution, chromosomal location, and functional characterization of the cDNA of such a transporter (NDCBE1) from human brain (GenBank accession number AF069512). NDCBE1, which encodes 1044 amino acids, is 34% identical to the mammalian anion exchanger (AE2); approximately 50% to the electrogenic Na/HCO3 cotransporter (NBCe1) from salamander, rat, and humans; approximately 73% to mammalian electroneutral Na/HCO3 cotransporters (NBCn1); 71% to mouse NCBE; and 47% to a Na(+)-driven anion exchanger (NDAE1) from Drosophila. Northern blot analysis of NDCBE1 shows a robust approximately 12-kilobase signal in all major regions of human brain and in testis, and weaker signals in kidney and ovary. This human gene (SLC4A8) maps to chromosome 12q13. When expressed in Xenopus oocytes and running in the forward direction, NDCBE1 is electroneutral and mediates increases in both pH(i) and [Na(+)](i) (monitored with microelectrodes) that require HCO3(-) and are blocked by 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS). The pH(i) increase also requires extracellular Na(+). The Na(+):HCO3(-) stoichiometry is 1:2. Forward-running NDCBE1 mediates a 36Cl efflux that requires extracellular Na(+) and HCO3(-) and is blocked by DIDS. Running in reverse, NDCBE1 requires extracellular Cl(-). Thus, NDCBE1 encodes a human, electroneutral Na(+)-driven Cl-HCO3 exchanger.

Urine concentrating mechanism: impact of vascular and tubular architecture and a proposed descending limb urea-Na+ cotransporter

PubMed Central

Dantzler, William H.; Pannabecker, Thomas L.

2012-01-01

We extended a region-based mathematical model of the renal medulla of the rat kidney, previously developed by us, to represent new anatomic findings on the vascular architecture in the rat inner medulla (IM). In the outer medulla (OM), tubules and vessels are organized around tightly packed vascular bundles; in the IM, the organization is centered around collecting duct clusters. In particular, the model represents the separation of descending vasa recta from the descending limbs of loops of Henle, and the model represents a papillary segment of the descending thin limb that is water impermeable and highly urea permeable. Model results suggest that, despite the compartmentalization of IM blood flow, IM interstitial fluid composition is substantially more homogeneous compared with OM. We used the model to study medullary blood flow in antidiuresis and the effects of vascular countercurrent exchange. We also hypothesize that the terminal aquaporin-1 null segment of the long descending thin limbs may express a urea-Na+ or urea-Cl− cotransporter. As urea diffuses from the urea-rich papillary interstitium into the descending thin limb luminal fluid, NaCl is secreted via the cotransporter against its concentration gradient. That NaCl is then reabsorbed near the loop bend, raising the interstitial fluid osmolality and promoting water reabsorption from the IM collecting ducts. Indeed, the model predicts that the presence of the urea-Na+ or urea- Cl− cotransporter facilitates the cycling of NaCl within the IM and yields a loop-bend fluid composition consistent with experimental data. PMID:22088433

Renal Na+-K+-Cl− cotransporter activity and vasopressin-induced trafficking are lipid raft-dependent

PubMed Central

Welker, Pia; Böhlick, Alexandra; Mutig, Kerim; Salanova, Michele; Kahl, Thomas; Schlüter, Hartmut; Blottner, Dieter; Ponce-Coria, Jose; Gamba, Gerardo; Bachmann, Sebastian

2008-01-01

Apical bumetanide-sensitive Na+-K+-2Cl− cotransporter (NKCC2), the kidney-specific member of a cation-chloride cotransporter superfamily, is an integral membrane protein responsible for the transepithelial reabsorption of NaCl. The role of NKCC2 is essential for renal volume regulation. Vasopressin (AVP) controls NKCC2 surface expression in cells of the thick ascending limb of the loop of Henle (TAL). We found that 40–70% of Triton X-100-insoluble NKCC2 was present in cholesterol-enriched lipid rafts (LR) in rat kidney and cultured TAL cells. The related Na+-Cl− cotransporter (NCC) from rat kidney was distributed in LR as well. NKCC2-containing LR were detected both intracellularly and in the plasma membrane. Bumetanide-sensitive transport of NKCC2 as analyzed by 86Rb+ influx in Xenopus laevis oocytes was markedly reduced by methyl-β-cyclodextrin (MβCD)-induced cholesterol depletion. In TAL, short-term AVP application induced apical vesicular trafficking along with a shift of NKCC2 from non-raft to LR fractions. In parallel, increased colocalization of NKCC2 with the LR ganglioside GM1 and their polar translocation were assessed by confocal analysis. Apical biotinylation showed twofold increases in NKCC2 surface expression. These effects were blunted by mevalonate-lovastatin/MβCD-induced cholesterol deprivation. Collectively, these findings demonstrate that a pool of NKCC2 distributes in rafts. Results are consistent with a model in which LR mediate polar insertion, activity, and AVP-induced trafficking of NKCC2 in the control of transepithelial NaCl transport. PMID:18579701

CD8+ T cells stimulate Na-Cl co-transporter NCC in distal convoluted tubules leading to salt-sensitive hypertension.

PubMed

Liu, Yunmeng; Rafferty, Tonya M; Rhee, Sung W; Webber, Jessica S; Song, Li; Ko, Benjamin; Hoover, Robert S; He, Beixiang; Mu, Shengyu

2017-01-09

Recent studies suggest a role for T lymphocytes in hypertension. However, whether T cells contribute to renal sodium retention and salt-sensitive hypertension is unknown. Here we demonstrate that T cells infiltrate into the kidney of salt-sensitive hypertensive animals. In particular, CD8 + T cells directly contact the distal convoluted tubule (DCT) in the kidneys of DOCA-salt mice and CD8 + T cell-injected mice, leading to up-regulation of the Na-Cl co-transporter NCC, p-NCC and the development of salt-sensitive hypertension. Co-culture with CD8 + T cells upregulates NCC in mouse DCT cells via ROS-induced activation of Src kinase, up-regulation of the K + channel Kir4.1, and stimulation of the Cl - channel ClC-K. The last event increases chloride efflux, leading to compensatory chloride influx via NCC activation at the cost of increasing sodium retention. Collectively, these findings provide a mechanism for adaptive immunity involvement in the kidney defect in sodium handling and the pathogenesis of salt-sensitive hypertension.

Late-onset manifestation of antenatal Bartter syndrome as a result of residual function of the mutated renal Na+-K+-2Cl- co-transporter.

PubMed

Pressler, Carsten A; Heinzinger, Jolanta; Jeck, Nikola; Waldegger, Petra; Pechmann, Ulla; Reinalter, Stephan; Konrad, Martin; Beetz, Rolf; Seyberth, Hannsjörg W; Waldegger, Siegfried

2006-08-01

Genetic defects of the Na+-K+-2Cl- (NKCC2) sodium potassium chloride co-transporter result in severe, prenatal-onset renal salt wasting accompanied by polyhydramnios, prematurity, and life-threatening hypovolemia of the neonate (antenatal Bartter syndrome or hyperprostaglandin E syndrome). Herein are described two brothers who presented with hyperuricemia, mild metabolic alkalosis, low serum potassium levels, and bilateral medullary nephrocalcinosis at the ages of 13 and 15 yr. Impaired function of sodium chloride reabsorption along the thick ascending limb of Henle's loop was deduced from a reduced increase in diuresis and urinary chloride excretion upon application of furosemide. Molecular genetic analysis revealed that the brothers were compound heterozygotes for mutations in the SLC12A1 gene coding for the NKCC2 co-transporter. Functional analysis of the mutated rat NKCC2 protein by tracer-flux assays after heterologous expression in Xenopus oocytes revealed significant residual transport activity of the NKCC2 p.F177Y mutant construct in contrast to no activity of the NKCC2-D918fs frameshift mutant construct. However, coexpression of the two mutants was not significantly different from that of NKCC2-F177Y alone or wild type. Membrane expression of NKCC2-F177Y as determined by luminometric surface quantification was not significantly different from wild-type protein, pointing to an intrinsic partial transport defect caused by the p.F177Y mutation. The partial function of NKCC2-F177Y, which is not negatively affected by NKCC2-D918fs, therefore explains a mild and late-onset phenotype and for the first time establishes a mild phenotype-associated SLC12A1 gene mutation.

Expression of Na+-glucose cotransporter (SGLT1) in visceral and parietal mesothelium of rabbit pleura.

PubMed

Sironi, Chiara; Bodega, Francesca; Porta, Cristina; Zocchi, Luciano; Agostoni, Emilio

2007-10-15

Indirect evidence for a solute-coupled liquid absorption from rabbit pleural space indicated that it should be caused by a Na(+)/H(+)-Cl(-)/HCO(3)(-) double exchanger and a Na(+)-glucose cotransporter [Agostoni, E., Zocchi, L., 1998. Mechanical coupling and liquid exchanges in the pleural space. In: Antony, V.B. (Ed.), Clinics in Chest Medicine: Diseases of the Pleura, vol. 19. Saunders, Philadelphia, pp. 241-260]. In this research we tried to obtain molecular evidence for Na(+)-glucose cotransporter (SGLT1) in visceral and parietal mesothelium of rabbit pleura. To this end we performed immunoblot assays on total protein extracts of scraped visceral or parietal mesothelium of rabbits. These showed two bands: one at 72kDa (m.w. of SGLT1), and one at 55kDa (which should also provide Na(+)-glucose cotransport). Both bands disappeared in assays in which SGLT1 antibody was preadsorbed with specific antigen. Molecular evidence for Na(+)/K(+) ATPase (alpha1 subunit) was also provided. Immunoblot assays for SGLT1 on cultured mesothelial cells of rabbit pleura showed a band at 72kDa, and in some cases also at 55kDa, irrespectively of treatment with a differentiating agent. Solute-coupled liquid absorption hinders liquid filtration through parietal mesothelium caused by Starling forces, and favours liquid absorption through visceral mesothelium caused by these forces.

Inactivation of the Na-Cl co-transporter (NCC) gene is associated with high BMD through both renal and bone mechanisms: analysis of patients with Gitelman syndrome and Ncc null mice.

PubMed

Nicolet-Barousse, Laurence; Blanchard, Anne; Roux, Christian; Pietri, Laurence; Bloch-Faure, May; Kolta, Sami; Chappard, Christine; Geoffroy, Valérie; Morieux, Caroline; Jeunemaitre, Xavier; Shull, Gary E; Meneton, Pierre; Paillard, Michel; Houillier, Pascal; De Vernejoul, Marie-Christine

2005-05-01

Chronic thiazide treatment is associated with high BMD. We report that patients and mice with null mutations in the thiazide-sensitive NaCl cotransporter (NCC) have higher renal tubular Ca reabsorption, higher BMD, and lower bone remodeling than controls, as well as abnormalities in Ca metabolism, mainly caused by Mg depletion. Chronic thiazide treatment decreases urinary Ca excretion (UVCa) and increases BMD. To understand the underlying mechanisms, Ca and bone metabolism were studied in two models of genetic inactivation of the thiazide-sensitive NaCl cotransporter (NCC): patients with Gitelman syndrome (GS) and Ncc knockout (Ncc(-/-)) mice. Ca metabolism was analyzed in GS patients and Ncc(-/-) mice under conditions of low dietary Ca. BMD was measured by DXA in patients and mice, and bone histomorphometry was analyzed in mice. GS patients had low plasma Mg. They exhibited reduced UVCa, but similar serum Ca and GFR as control subjects, suggesting increased renal Ca reabsorption. Blood PTH was lower despite lower serum ionized Ca, and Mg repletion almost corrected both relative hypoparathyroidism and low UVCa. BMD was significantly increased in GS patients at both lumbar (+7%) and femoral (+16%) sites, and osteocalcin was reduced. In Ncc(-/-) mice, serum Ca and GFR were unchanged, but UVCa was reduced and PTH was elevated; Mg repletion largely corrected both abnormalities. Trabecular and cortical BMD were higher than in Ncc(+/+) mice (+4% and +5%, respectively), and despite elevated PTH, were associated with higher cortical thickness and lower endosteal osteoclastic surface. Higher BMD is observed in GS patients and Ncc(-/-) mice. Relative hypoparathyroidism (human) and bone resistance to PTH (mice), mainly caused by Mg depletion, can explain the low bone remodeling and normal/low serum Ca despite increased renal Ca reabsorption.

CD8+ T cells stimulate Na-Cl co-transporter NCC in distal convoluted tubules leading to salt-sensitive hypertension

PubMed Central

Liu, Yunmeng; Rafferty, Tonya M.; Rhee, Sung W.; Webber, Jessica S.; Song, Li; Ko, Benjamin; Hoover, Robert S.; He, Beixiang; Mu, Shengyu

2017-01-01

Recent studies suggest a role for T lymphocytes in hypertension. However, whether T cells contribute to renal sodium retention and salt-sensitive hypertension is unknown. Here we demonstrate that T cells infiltrate into the kidney of salt-sensitive hypertensive animals. In particular, CD8+ T cells directly contact the distal convoluted tubule (DCT) in the kidneys of DOCA-salt mice and CD8+ T cell-injected mice, leading to up-regulation of the Na-Cl co-transporter NCC, p-NCC and the development of salt-sensitive hypertension. Co-culture with CD8+ T cells upregulates NCC in mouse DCT cells via ROS-induced activation of Src kinase, up-regulation of the K+ channel Kir4.1, and stimulation of the Cl− channel ClC-K. The last event increases chloride efflux, leading to compensatory chloride influx via NCC activation at the cost of increasing sodium retention. Collectively, these findings provide a mechanism for adaptive immunity involvement in the kidney defect in sodium handling and the pathogenesis of salt-sensitive hypertension. PMID:28067240

Interleukin 18 function requires both interleukin 18 receptor and Na-Cl co-transporter

PubMed Central

Wang, Jing; Sun, Chongxiu; Gerdes, Norbert; Liu, Conglin; Liao, Mengyang; Liu, Jian; Shi, Michael A.; He, Aina; Zhou, Yi; Sukhova, Galina K.; Chen, Huimei; Cheng, Xianwu; Kuzuya, Masafumi; Murohara, Toyoaki; Zhang, Jie; Cheng, Xiang; Jiang, Mengmeng; Shull, Gary E.; Rogers, Shaunessy; Yang, Chao-Ling; Ke, Qiang; Jelen, Sabina; Bindels, René; Ellison, David H.; Jarolim, Petr; Libby, Peter; Shi, Guo-Ping

2015-01-01

Interleukin-18 (IL18) participates in atherogenesis through several putative mechanisms1,2. Interruption of IL18 action reduces atherosclerosis in mice3,4. This study shows that the absence of IL18 receptor (IL18r) does not affect atherosclerosis in apolipoprotein E-deficient (Apoe−/−) mice, nor does it affect IL18 cell surface binding or signaling. IL18 antibody-mediated immunoprecipitation identified an interaction between IL18 and Na-Cl co-transporter (NCC), a 12-transmembrane-domain ion transporter protein preferentially expressed in the kidney5. Yet, we find NCC expression and colocalization with IL18r in atherosclerotic lesions and both molecules form a complex. IL18 also binds to the cell surface and induces cell signaling and down-stream cytokine expression in NCC-transfected COS-7 cells that do not express IL18r. In Apoe−/− mice, combined deficiency of IL18r and NCC, but not single deficiency, protects mice from atherosclerosis. Peritoneal macrophages from Apoe−/− mice or those lacking IL18r or NCC respond to IL18 binding or IL18 induction of cell signaling and cytokine and chemokine production, but those with combined deficiency of IL18r and NCC do not. This study identifies NCC as an IL18-binding protein that coordinates with IL18r in cell signaling, inflammatory molecule expression, and experimental atherogenesis. PMID:26099046

Rapid increase in red blood cell density driven by K:Cl cotransport in a subset of sickle cell anemia reticulocytes and discocytes.

PubMed

Fabry, M E; Romero, J R; Buchanan, I D; Suzuka, S M; Stamatoyannopoulos, G; Nagel, R L; Canessa, M

1991-07-01

We have previously demonstrated that young normal (AA) and sickle cell anemia (SS) red blood cells are capable of a volume regulatory decrease response (VRD) driven by a K:Cl cotransporter that is activated by low pH or hypotonic conditions. We now report on the characteristics of young SS cells (SS2, discocytes) capable of rapid increase in density in response to swelling. We have isolated cells with high VRD response (H-VRD) and low VRD response (L-VRD) cells by incubation and density-gradient centrifugation under hypotonic conditions. Comparison of these cells in patients homozygous for hemoglobin (Hb)S indicated that H-VRD cells have 91% more reticulocytes (P less than 9 x 10(-9) than L-VRD cells, 25% less HbF (P less than 5.5 x 10(-5), 106% more NEM (N-methylmaleimide)-stimulated K:Cl cotransport activity (P less than 2 x 10(-4), and 86% more volume-stimulated K:Cl cotransport activity (P less than 1.8 x 10(-3). H-VRD and L-VRD cells have similar G-6-PD and Na+/H+ antiport activity. In agreement with the reduced percent HbF in H-VRD cells, F cells (red blood cells that contain fetal Hb) are depleted from the H-VRD population; however, F reticulocytes are enriched in the H-VRD population to the same extent as non-F reticulocytes, which suggests that both F and non-F reticulocytes have a similar initial distribution of volume-sensitive K:Cl cotransport activity but that it may be more rapidly inactivated in F than in S reticulocytes. We find that H-VRD cells consist of 20% reticulocytes (or 79% of all reticulocytes in SS2) and 80% more mature cells. This study demonstrates the role of K:Cl cotransport in determining red blood cell density, the heterogeneity of K:Cl cotransport activity in reticulocytes, and the capacity for rapid change in the density of reticulocytes with high K:Cl cotransport activity. We speculate that the H-VRD population may be more susceptible to generation of dense and irreversibly sickled cells.

Na-K-Cl Cotransporter-1 in the Mechanism of Ammonia-induced Astrocyte Swelling*

PubMed Central

Jayakumar, Arumugam R.; Liu, Mingli; Moriyama, Mitsuaki; Ramakrishnan, Ramugounder; Forbush, Bliss; Reddy, Pichili V. B.; Norenberg, Michael D.

2008-01-01

Brain edema and the consequent increase in intracranial pressure and brain herniation are major complications of acute liver failure (fulminant hepatic failure) and a major cause of death in this condition. Ammonia has been strongly implicated as an important factor, and astrocyte swelling appears to be primarily responsible for the edema. Ammonia is known to cause cell swelling in cultured astrocytes, although the means by which this occurs has not been fully elucidated. A disturbance in one or more of these systems may result in loss of ion homeostasis and cell swelling. In particular, activation of the Na-K-Cl cotransporter (NKCC1) has been shown to be involved in cell swelling in several neurological disorders. We therefore examined the effect of ammonia on NKCC activity and its potential role in the swelling of astrocytes. Cultured astrocytes were exposed to ammonia (NH4Cl; 5 mm), and NKCC activity was measured. Ammonia increased NKCC activity at 24 h. Inhibition of this activity by bumetanide diminished ammonia-induced astrocyte swelling. Ammonia also increased total as well as phosphorylated NKCC1. Treatment with cyclohexamide, a potent inhibitor of protein synthesis, diminished NKCC1 protein expression and NKCC activity. Since ammonia is known to induce oxidative/nitrosative stress, and antioxidants and nitric-oxide synthase inhibition diminish astrocyte swelling, we also examined whether ammonia caused oxidation and/or nitration of NKCC1. Cultures exposed to ammonia increased the state of oxidation and nitration of NKCC1, whereas the antioxidants N-nitro-l-arginine methyl ester and uric acid all significantly diminished NKCC activity. These agents also reduced phosphorylated NKCC1 expression. These results suggest that activation of NKCC1 is an important factor in the mediation of astrocyte swelling by ammonia and that such activation appears to be mediated by NKCC1 abundance as well as by its oxidation/nitration and phosphorylation. PMID:18849345

With no lysine L-WNK1 isoforms are negative regulators of the K+-Cl- cotransporters.

PubMed

Mercado, Adriana; de Los Heros, Paola; Melo, Zesergio; Chávez-Canales, María; Murillo-de-Ozores, Adrián R; Moreno, Erika; Bazúa-Valenti, Silvana; Vázquez, Norma; Hadchouel, Juliette; Gamba, Gerardo

2016-07-01

The K(+)-Cl(-) cotransporters (KCC1-KCC4) encompass a branch of the SLC12 family of electroneutral cation-coupled chloride cotransporters that translocate ions out of the cell to regulate various factors, including cell volume and intracellular chloride concentration, among others. L-WNK1 is an ubiquitously expressed kinase that is activated in response to osmotic stress and intracellular chloride depletion, and it is implicated in two distinct hereditary syndromes: the renal disease pseudohypoaldosteronism type II (PHAII) and the neurological disease hereditary sensory neuropathy 2 (HSN2). The effect of L-WNK1 on KCC activity is unknown. Using Xenopus laevis oocytes and HEK-293 cells, we show that the activation of KCCs by cell swelling was prevented by L-WNK1 coexpression. In contrast, the activity of the Na(+)-K(+)-2Cl(-) cotransporter NKCC1 was remarkably increased with L-WNK1 coexpression. The negative effect of L-WNK1 on the KCCs is kinase dependent. Elimination of the STE20 proline-alanine rich kinase (SPAK)/oxidative stress-responsive kinase (OSR1) binding site or the HQ motif required for the WNK-WNK interaction prevented the effect of L-WNK1 on KCCs, suggesting a required interaction between L-WNK1 molecules and SPAK. Together, our data support that NKCC1 and KCCs are coordinately regulated by L-WNK1 isoforms. Copyright © 2016 the American Physiological Society.

Double knockout of carbonic anhydrase II (CAII) and Na(+)-Cl(-) cotransporter (NCC) causes salt wasting and volume depletion.

PubMed

Xu, Jie; Barone, Sharon; Brooks, Mary-Beth; Soleimani, Manoocher

2013-01-01

The thiazide-sensitive Na(+)-Cl(-) cotransporter NCC and the Cl(-)/HCO3(-)exchanger pendrin are expressed on apical membranes of distal cortical nephron segments and mediate salt absorption, with pendrin working in tandem with the epithelial Na(+) channel (ENaC) and the Na(+)-dependent chloride/bicarbonate exchanger (NDCBE), whereas NCC is working by itself. A recent study showed that NCC and pendrin compensate for loss of each other under basal conditions, therefore masking the role that each plays in salt reabsorption. Carbonic anhydrase II (CAII, CA2 or CAR2) plays an important role in acid-base transport and salt reabsorption in the proximal convoluted tubule and acid-base transport in the collecting duct. Animals with CAII deletion show remodeling of intercalated cells along with the downregulation of pendrin. NCC KO mice on the other hand show significant upregulation of pendrin and ENaC. Neither model shows any significant salt wasting under baseline conditions. We hypothesized that the up-regulation of pendrin is essential for the prevention of salt wasting in NCC KO mice. To test this hypothesis, we generated NCC/CAII double KO (dKO) mice by crossing mice with single deletion of NCC and CAII. The NCC/CAII dKO mice displayed significant downregulation of pendrin, along with polyuria and salt wasting. As a result, the dKO mice developed volume depletion, which was associated with the inability to concentrate urine. We conclude that the upregulation of pendrin is essential for the prevention of salt and water wasting in NCC deficient animals and its downregulation or inactivation will result in salt wasting, impaired water conservation and volume depletion in the setting of NCC inactivation or inhibition. © 2014 S. Karger AG, Basel.

Long-term myocardial preservation: effects of hyperkalemia, sodium channel, and Na/K/2Cl cotransport inhibition on extracellular potassium accumulation during hypothermic storage.

PubMed

Snabaitis, A K; Shattock, M J; Chambers, D J

1999-07-01

We previously demonstrated improved myocardial preservation with polarized (tetrodotoxin-induced), compared with depolarized (hyperkalemia-induced), arrest and hypothermic storage. This study was undertaken to determine whether polarized arrest reduced ionic imbalance during ischemic storage and whether this was influenced by Na+/K +/2Cl- cotransport inhibition. We used the isolated crystalloid perfused working rat heart preparation (1) to measure extracellular K+ accumulation (using a K+-sensitive intramyocardial electrode) during ischemic (control), depolarized (K+ 16 mmol/L), and polarized (tetrodotoxin, 22 micromol/L) arrest and hypothermic (7.5 degrees C) storage (5 hours), (2) to determine dose-dependent (0.1, 1.0, 10 and 100 micromol/L) effects of the Na +/K+/2Cl- cotransport inhibitor, furosemide, on extracellular K+ accumulation during polarized arrest and 7.5 degrees C storage, and (3) to correlate extracellular K+ accumulation to postischemic recovery of cardiac function. Characteristic triphasic profiles of extracellular K+ accumulation were observed in control and depolarized arrested hearts; a significantly attenuated profile with polarized arrested hearts demonstrated reduced extracellular K+ accumulation, correlating with higher postischemic function (recovery of aortic flow was 54% +/-4% [P =.01] compared with 39% +/-3% and 32% +/-3% in depolarized and control hearts, respectively). Furosemide (0.1, 1.0, 10, and 100 micromol/L) modified extracellular K+ accumulation by -18%, -38%, -0.2%, and +9%, respectively, after 30 minutes and by -4%, -27%, +31%, and +42%, respectively, after 5 hours of polarized storage. Recovery of aortic flow was 53% +/-4% (polarized arrest alone), 56% +/-8%, 70% +/-2% (P =.04 vs control), 69% +/-4% (P =.04 vs control), and 65% +/-3% ( P =. 04 vs control), respectively. Polarized arrest was associated with a reduced ionic imbalance (demonstrated by reduced extracellular K+ accumulation) and improved recovery of cardiac

Dynamin2, Clathrin, and Lipid Rafts Mediate Endocytosis of the Apical Na/K/2Cl Cotransporter NKCC2 in Thick Ascending Limbs*

PubMed Central

Ares, Gustavo R.; Ortiz, Pablo A.

2012-01-01

Steady-state surface levels of the apical Na/K/2Cl cotransporter NKCC2 regulate NaCl reabsorption by epithelial cells of the renal thick ascending limb (THAL). We reported that constitutive endocytosis of NKCC2 controls NaCl absorption in native THALs; however, the pathways involved in NKCC2 endocytosis are unknown. We hypothesized that NKCC2 endocytosis at the apical surface depends on dynamin-2 and clathrin. Measurements of steady-state surface NKCC2 and the rate of NKCC2 endocytosis in freshly isolated rat THALs showed that inhibition of endogenous dynamin-2 with dynasore blunted NKCC2 endocytosis by 56 ± 11% and increased steady-state surface NKCC2 by 67 ± 27% (p < 0.05). Expression of the dominant negative Dyn2K44A in THALs slowed the rate of NKCC2 endocytosis by 38 ± 8% and increased steady-state surface NKCC2 by 37 ± 8%, without changing total NKCC2 expression. Inhibition of clathrin-mediated endocytosis with chlorpromazine blunted NKCC2 endocytosis by 54 ± 6%, while preventing clathrin from interacting with synaptojanin also blunted NKCC2 endocytosis by 52 ± 5%. Disruption of lipid rafts blunted NKCC2 endocytosis by 39 ± 4% and silencing caveolin-1 by 29 ± 4%. Simultaneous inhibition of clathrin- and lipid raft-mediated endocytosis completely blocked NKCC2 internalization. We concluded that dynamin-2, clathrin, and lipid rafts mediate NKCC2 endocytosis and maintain steady-state apical surface NKCC2 in native THALs. These are the first data identifying the endocytic pathway for apical NKCC2 endocytosis. PMID:22977238

Sodium-bicarbonate cotransport in retinal Müller (glial) cells of the salamander.

PubMed

Newman, E A

1991-12-01

An electrogenic Na+/HCO3- cotransport system was studied in freshly dissociated Müller cells of the salamander retina. Cotransporter currents were recorded from isolated cells using the whole-cell, voltage-clamp technique following the block of K+ conductance with external Ba2+ and internal Cs+. At constant pHo, an outward current was evoked when extracellular HCO3- concentration was raised by pressure ejecting a HCO3(-)-buffered solution onto the surface of cells bathed in nominally HCO3(-)-free solution. The HCO3(-)-evoked outward current was reduced to 4.4% of control by 0.5 mM DIDS (4,4'-diisothiocyanatostilbene-2,2'-disulfonate), to 28.8% of control by 2 mM DNDS (4,4'-dinitrostilbene-2,2'-disulfonate), and to 28.4% of control by 2 mM harmaline. Substitution of choline for Na+ in bath and ejection solutions reduced the response to 1.3% of control. Bicarbonate-evoked currents of normal magnitude were recorded when methane sulfonate was substituted for Cl- in bath, ejection, and intracellular solutions. Similarly, an outward current was evoked when extracellular Na+ concentration was raised in the presence of HCO3-. The Na(+)-evoked response was reduced to 16.2% of control by 2 mM DNDS and was abolished by removal of HCO3- from bath and ejection solutions. Taken together, these results (block by stilbenes and harmaline, HCO3- and Na+ dependence, Cl- independence) indicate that salamander Müller cells possess an electrogenic Na+/HCO3- cotransport system. Na+/HCO3- cotransporter sites were localized primarily at the endfoot region of Müller cells. Ejection of HCO3- onto the endfoot evoked outward currents 10 times larger than currents evoked by ejections onto the opposite (distal) end of the cell. The reversal potential of the cotransporter was determined by DNDS block of cotransport current. In the absence of a transmembrane HCO3- gradient, the reversal potential varied systematically as a function of the transmembrane Na+ gradient. The reversal potential was

Extracellular K+ rapidly controls NaCl cotransporter phosphorylation in the native distal convoluted tubule by Cl−‐dependent and independent mechanisms

PubMed Central

Penton, David; Czogalla, Jan; Wengi, Agnieszka; Himmerkus, Nina; Loffing‐Cueni, Dominique; Carrel, Monique; Rajaram, Renuga Devi; Staub, Olivier; Bleich, Markus; Schweda, Frank

2016-01-01

Key points High dietary potassium (K+) intake dephosphorylates and inactivates the NaCl cotransporter (NCC) in the renal distal convoluted tubule (DCT).Using several ex vivo models, we show that physiological changes in extracellular K+, similar to those occurring after a K+ rich diet, are sufficient to promote a very rapid dephosphorylation of NCC in native DCT cells.Although the increase of NCC phosphorylation upon decreased extracellular K+ appears to depend on cellular Cl− fluxes, the rapid NCC dephosphorylation in response to increased extracellular K+ is not Cl−‐dependent.The Cl−‐dependent pathway involves the SPAK/OSR1 kinases, whereas the Cl− independent pathway may include additional signalling cascades. Abstract A high dietary potassium (K+) intake causes a rapid dephosphorylation, and hence inactivation, of the thiazide‐sensitive NaCl cotransporter (NCC) in the renal distal convoluted tubule (DCT). Based on experiments in heterologous expression systems, it was proposed that changes in extracellular K+ concentration ([K+]ex) modulate NCC phosphorylation via a Cl−‐dependent modulation of the with no lysine (K) kinases (WNK)‐STE20/SPS‐1‐44 related proline‐alanine‐rich protein kinase (SPAK)/oxidative stress‐related kinase (OSR1) kinase pathway. We used the isolated perfused mouse kidney technique and ex vivo preparations of mouse kidney slices to test the physiological relevance of this model on native DCT. We demonstrate that NCC phosphorylation inversely correlates with [K+]ex, with the most prominent effects occurring around physiological plasma [K+]. Cellular Cl− conductances and the kinases SPAK/OSR1 are involved in the phosphorylation of NCC under low [K+]ex. However, NCC dephosphorylation triggered by high [K+]ex is neither blocked by removing extracellular Cl−, nor by the Cl− channel blocker 4,4′‐diisothiocyano‐2,2′‐stilbenedisulphonic acid. The response to [K+]ex on a low extracellular chloride

Regulated phosphorylation of the K-Cl cotransporter KCC3 is a molecular switch of intracellular potassium content and cell volume homeostasis.

PubMed

Adragna, Norma C; Ravilla, Nagendra B; Lauf, Peter K; Begum, Gulnaz; Khanna, Arjun R; Sun, Dandan; Kahle, Kristopher T

2015-01-01

The defense of cell volume against excessive shrinkage or swelling is a requirement for cell function and organismal survival. Cell swelling triggers a coordinated homeostatic response termed regulatory volume decrease (RVD), resulting in K(+) and Cl(-) efflux via activation of K(+) channels, volume-regulated anion channels (VRACs), and the K(+)-Cl(-) cotransporters, including KCC3. Here, we show genetic alanine (Ala) substitution at threonines (Thr) 991 and 1048 in the KCC3a isoform carboxyl-terminus, preventing inhibitory phosphorylation at these sites, not only significantly up-regulates KCC3a activity up to 25-fold in normally inhibitory isotonic conditions, but is also accompanied by reversal of activity of the related bumetanide-sensitive Na(+)-K(+)-2Cl(-) cotransporter isoform 1 (NKCC1). This results in a rapid (<10 min) and significant (>90%) reduction in intracellular K(+) content (Ki) via both Cl-dependent (KCC3a + NKCC1) and Cl-independent [DCPIB (VRAC inhibitor)-sensitive] pathways, which collectively renders cells less prone to acute swelling in hypotonic osmotic stress. Together, these data demonstrate the phosphorylation state of Thr991/Thr1048 in KCC3a encodes a potent switch of transporter activity, Ki homeostasis, and cell volume regulation, and reveal novel observations into the functional interaction among ion transport molecules involved in RVD.

NaCl regulation of plasma membrane H(+)-ATPase gene expression in a glycophyte and a halophyte.

PubMed

Niu, X; Narasimhan, M L; Salzman, R A; Bressan, R A; Hasegawa, P M

1993-11-01

NaCl regulation of plasma membrane H(+)-ATPase gene expression in the glycophyte tobacco (Nicotiana tabacum L. var Wisconsin 38) and the halophyte Atriplex nummularia L. was evaluated by comparison of organ-specific mRNA abundance using homologous cDNA probes encoding the ATPases of the respective plants. Accumulation of mRNA was induced by NaCl in fully expanded leaves and in roots but not in expanding leaves or stems. The NaCl responsiveness of the halophyte to accumulate plasma membrane H(+)-ATPase mRNA in roots was substantially greater than that of the glycophyte. Salt-induced transcript accumulation in A. nummularia roots was localized by in situ hybridization predominantly to the elongation zone, but mRNA levels also increased in the zone of differentiation. Increased message accumulation in A. nummularia roots could be detected within 8 h after NaCl (400 mM) treatment, and maximal levels were severalfold greater than in roots of untreated control plants. NaCl-induced plasma membrane H(+)-ATPase gene expression in expanded leaves and roots presumably indicates that these organs require increased H(+)-electrochemical potential gradients for the maintenance of plant ion homeostasis for salt adaptation. The greater capacity of the halophyte to induce plasma membrane H(+)-ATPase gene expression in response to NaCl may be a salt-tolerance determinant.

NaCl regulation of plasma membrane H(+)-ATPase gene expression in a glycophyte and a halophyte.

PubMed Central

Niu, X; Narasimhan, M L; Salzman, R A; Bressan, R A; Hasegawa, P M

1993-01-01

NaCl regulation of plasma membrane H(+)-ATPase gene expression in the glycophyte tobacco (Nicotiana tabacum L. var Wisconsin 38) and the halophyte Atriplex nummularia L. was evaluated by comparison of organ-specific mRNA abundance using homologous cDNA probes encoding the ATPases of the respective plants. Accumulation of mRNA was induced by NaCl in fully expanded leaves and in roots but not in expanding leaves or stems. The NaCl responsiveness of the halophyte to accumulate plasma membrane H(+)-ATPase mRNA in roots was substantially greater than that of the glycophyte. Salt-induced transcript accumulation in A. nummularia roots was localized by in situ hybridization predominantly to the elongation zone, but mRNA levels also increased in the zone of differentiation. Increased message accumulation in A. nummularia roots could be detected within 8 h after NaCl (400 mM) treatment, and maximal levels were severalfold greater than in roots of untreated control plants. NaCl-induced plasma membrane H(+)-ATPase gene expression in expanded leaves and roots presumably indicates that these organs require increased H(+)-electrochemical potential gradients for the maintenance of plant ion homeostasis for salt adaptation. The greater capacity of the halophyte to induce plasma membrane H(+)-ATPase gene expression in response to NaCl may be a salt-tolerance determinant. PMID:8022933

Double knockout of pendrin and Na-Cl cotransporter (NCC) causes severe salt wasting, volume depletion, and renal failure.

PubMed

Soleimani, Manoocher; Barone, Sharon; Xu, Jie; Shull, Gary E; Siddiqui, Faraz; Zahedi, Kamyar; Amlal, Hassane

2012-08-14

The Na-Cl cotransporter (NCC), which is the target of inhibition by thiazides, is located in close proximity to the chloride-absorbing transporter pendrin in the kidney distal nephron. Single deletion of pendrin or NCC does not cause salt wasting or excessive diuresis under basal conditions, raising the possibility that these transporters are predominantly active during salt depletion or in response to excess aldosterone. We hypothesized that pendrin and NCC compensate for loss of function of the other under basal conditions, thereby masking the role that each plays in salt absorption. To test our hypothesis, we generated pendrin/NCC double knockout (KO) mice by crossing pendrin KO mice with NCC KO mice. Pendrin/NCC double KO mice displayed severe salt wasting and sharp increase in urine output under basal conditions. As a result, animals developed profound volume depletion, renal failure, and metabolic alkalosis without hypokalemia, which were all corrected with salt replacement. We propose that the combined inhibition of pendrin and NCC can provide a strong diuretic regimen without causing hypokalemia for patients with fluid overload, including patients with congestive heart failure, nephrotic syndrome, diuretic resistance, or generalized edema.

Double knockout of pendrin and Na-Cl cotransporter (NCC) causes severe salt wasting, volume depletion, and renal failure

PubMed Central

Soleimani, Manoocher; Barone, Sharon; Xu, Jie; Shull, Gary E.; Siddiqui, Faraz; Zahedi, Kamyar; Amlal, Hassane

2012-01-01

The Na-Cl cotransporter (NCC), which is the target of inhibition by thiazides, is located in close proximity to the chloride-absorbing transporter pendrin in the kidney distal nephron. Single deletion of pendrin or NCC does not cause salt wasting or excessive diuresis under basal conditions, raising the possibility that these transporters are predominantly active during salt depletion or in response to excess aldosterone. We hypothesized that pendrin and NCC compensate for loss of function of the other under basal conditions, thereby masking the role that each plays in salt absorption. To test our hypothesis, we generated pendrin/NCC double knockout (KO) mice by crossing pendrin KO mice with NCC KO mice. Pendrin/NCC double KO mice displayed severe salt wasting and sharp increase in urine output under basal conditions. As a result, animals developed profound volume depletion, renal failure, and metabolic alkalosis without hypokalemia, which were all corrected with salt replacement. We propose that the combined inhibition of pendrin and NCC can provide a strong diuretic regimen without causing hypokalemia for patients with fluid overload, including patients with congestive heart failure, nephrotic syndrome, diuretic resistance, or generalized edema. PMID:22847418

Renal-Specific Silencing of TNF (Tumor Necrosis Factor) Unmasks Salt-Dependent Increases in Blood Pressure via an NKCC2A (Na+-K+-2Cl- Cotransporter Isoform A)-Dependent Mechanism.

PubMed

Hao, Shoujin; Hao, Mary; Ferreri, Nicholas R

2018-06-01

We tested the hypothesis that TNF (tumor necrosis factor)-α produced within the kidney and acting on the renal tubular system is part of a regulatory mechanism that attenuates increases in blood pressure in response to high salt intake. Intrarenal administration of a lentivirus construct, which specifically silenced TNF in the kidney, did not affect baseline blood pressure. However, blood pressure increased significantly 1 day after mice with intrarenal silencing of TNF ingested 1% NaCl in the drinking water. The increase in blood pressure, which was continuously observed for 11 days, promptly returned to baseline levels when mice were switched from 1% NaCl to tap water. Silencing of renal TNF also increased NKCC2 (Na + -K + -2Cl - cotransporter) phosphorylation and induced a selective increase in NKCC2A (NKCC2 isoform A) mRNA accumulation in both the cortical and medullary thick ascending limb of Henle loop that was neither associated with a compensatory decrease of NKCC2F in the medulla nor NKCC2B in the cortex. The NaCl-mediated increases in blood pressure were completely absent when NKCC2A, using a lentivirus construct that did not alter expression of NKCC2F or NKCC2B, and TNF were concomitantly silenced in the kidney. Moreover, the decrease in urine volume and NaCl excretion induced by renal TNF silencing was abolished when NKCC2A was concurrently silenced, suggesting that this isoform contributes to the transition from a salt-resistant to salt-sensitive phenotype. Collectively, the data are the first to demonstrate a role for TNF produced by the kidney in the modulation of sodium homeostasis and blood pressure regulation. © 2018 American Heart Association, Inc.

Expression of a highly basic peroxidase gene in NaCl-adapted tomato cell suspensions.

PubMed

Medina, M I; Botella, M A; Quesada, M A; Valpuesta, V

1997-05-05

A tomato peroxidase gene, TPX2, that is only weakly expressed in the roots of young tomato seedlings is highly expressed in tomato suspension cells adapted to high external NaCl concentration. The protein encoded by this gene, with an isolectric point value of approximately 9.6, is found in the culture medium of the growing cells. Our data suggest that the expression of TPX2 in the salt-adapted cells is not the result of the elicitation imposed by the in vitro culture or the presence of high NaCl concentration in the medium.

A thermodynamic study of electroneutral K-Cl cotransport in pH- and volume-clamped low K sheep erythrocytes with normal and low internal magnesium.

PubMed

Lauf, P K; Adragna, N C

1996-10-01

Swelling-induced human erythrocyte K-Cl cotransport is membrane potential independent and capable of uphill transport. However, a complete thermodynamic analysis of basal and stimulated K-Cl cotransport, at constant cell volume, is missing. This study was performed in low K sheep red blood cells before and after reducing cellular free Mg into the nanomolar range with the divalent cation ionophore A23187 and a chelator, an intervention known to stimulate K-Cl cotransport. The anion exchange inhibitor 4,4'diisothiocyanato-2,2'disulfonic stilbene was used to clamp intracellular pH and Cl or NO3 concentrations. Cell volume was maintained constant as external and internal pH differed by more than two units. K-Cl cotransport was calculated from the K effluxes and Rb (as K congener) influxes measured in Cl and NO3, at constant internal K and external anions, and variable concentrations of extracellular Rb and internal anions, respectively. The external Rb concentration at which net K-Cl cotransport is zero was defined as flux reversal point which changed with internal pH and hence Cl. Plots of the ratio of external Rb concentrations corresponding to the flux reversal points and the internal K concentration versus the ratio of the internal and external Cl concentrations (i.e., the Donnan ratio of the transported ions) yielded slopes near unity for both control and low internal Mg cells. Thus, basal as well as low internal Mg-stimulated net K-Cl cotransport depends on the electrochemical potential gradient of KCl.

A thermodynamic study of electroneutral K-Cl cotransport in pH- and volume-clamped low K sheep erythrocytes with normal and low internal magnesium

PubMed Central

1996-01-01

Swelling-induced human erythrocyte K-Cl cotransport is membrane potential independent and capable of uphill transport. However, a complete thermodynamic analysis of basal and stimulated K-Cl cotransport, at constant cell volume, is missing. This study was performed in low K sheep red blood cells before and after reducing cellular free Mg into the nanomolar range with the divalent cation ionophore A23187 and a chelator, an intervention known to stimulate K- Cl cotransport. The anion exchange inhibitor 4,4'diisothiocyanato- 2,2'disulfonic stilbene was used to clamp intracellular pH and Cl or NO3 concentrations. Cell volume was maintained constant as external and internal pH differed by more than two units. K-Cl cotransport was calculated from the K effluxes and Rb (as K congener) influxes measured in Cl and NO3, at constant internal K and external anions, and variable concentrations of extracellular Rb and internal anions, respectively. The external Rb concentration at which net K-Cl cotransport is zero was defined as flux reversal point which changed with internal pH and hence Cl. Plots of the ratio of external Rb concentrations corresponding to the flux reversal points and the internal K concentration versus the ratio of the internal and external Cl concentrations (i.e., the Donnan ratio of the transported ions) yielded slopes near unity for both control and low internal Mg cells. Thus, basal as well as low internal Mg-stimulated net K-Cl cotransport depends on the electrochemical potential gradient of KCl. PMID:8894982

Generation and analysis of the thiazide-sensitive Na+ -Cl- cotransporter (Ncc/Slc12a3) Ser707X knockin mouse as a model of Gitelman syndrome.

PubMed

Yang, Sung-Sen; Lo, Yi-Fen; Yu, I-Shing; Lin, Shu-Wha; Chang, Tai-Hsiang; Hsu, Yu-Juei; Chao, Tai-Kuang; Sytwu, Huey-Kang; Uchida, Shinichi; Sasaki, Sei; Lin, Shih-Hua

2010-12-01

Gitelman syndrome (GS) is characterized by salt-losing hypotension, hypomagnesemia, hypokalemic metabolic alkalosis, and hypocalciuria. To better model human GS caused by a specific mutation in the thiazide-sensitive Na(+) -Cl(-) cotransporter (NCC) gene SLC12A3, we generated a nonsense Ncc Ser707X knockin mouse corresponding to human p.Ser710X (c.2135C>A), a recurrent mutation with severe phenotypes in Chinese GS patients. Compared with wild-type or heterozygous littermates, homozygous (Hom) knockin mice fully recapitulated the phenotype of human GS. The markedly reduced Ncc mRNA and virtually absent Ncc protein expression in kidneys of Hom mice was primarily due to nonsense-mediated mRNA decay (NMD) surveillance mechanisms. Expression of epithelial Na(+) channel (Enac), Ca(2+) channels (Trpv5 and Trpv6), and K(+) channels (Romk1 and maxi-K) were significantly increased. Late distal convoluted tubules (DCT) volume was increased and DCT cell ultrastructure appeared intact. High K(+) intake could not correct hypokalemia but caused a further increase in maxi-K but not Romk1 expression. Renal tissue from a patient with GS also showed the enhanced TRPV5 and ROMK1 expression in distal tubules. We suggest that the upregulation of TRPV5/6 and of ROMK1 and Maxi-K may contribute to hypocalciuria and hypokalemia in Ncc Ser707X knockin mice and human GS, respectively. © 2010 Wiley-Liss, Inc.

Downregulation of NCC and NKCC2 cotransporters by kidney-specific WNK1 revealed by gene disruption and transgenic mouse models.

PubMed

Liu, Zhen; Xie, Jian; Wu, Tao; Truong, Thao; Auchus, Richard J; Huang, Chou-Long

2011-03-01

WNK1 (with-no-lysine[K]-1) is a protein kinase of which mutations cause a familial hypertension and hyperkalemia syndrome known as pseudohypoaldosteronism type 2 (PHA2). Kidney-specific (KS) WNK1 is an alternatively spliced form of WNK1 kinase missing most of the kinase domain. KS-WNK1 downregulates the Na(+)-Cl(-) cotransporter NCC by antagonizing the effect of full-length WNK1 when expressed in Xenopus oocytes. The physiological role of KS-WNK1 in the regulation of NCC and potentially other Na(+) transporters in vivo is unknown. Here, we report that mice overexpressing KS-WNK1 in the kidney exhibited renal Na(+) wasting, elevated plasma levels of angiotensin II and aldosterone yet lower blood pressure relative to wild-type littermates. Immunofluorescent staining revealed reduced surface expression of total and phosphorylated NCC and the Na(+)-K(+)-2Cl(-) cotransporter NKCC2 in the distal convoluted tubule and the thick ascending limb of Henle's loop, respectively. Conversely, mice with targeted deletion of exon 4A (the first exon for KS-WNK1) exhibited Na(+) retention, elevated blood pressure on a high-Na(+) diet and increased surface expression of total and phosphorylated NCC and NKCC2 in respective nephron segments. Thus, KS-WNK1 is a negative regulator of NCC and NKCC2 in vivo and plays an important role in the control of Na(+) homeostasis and blood pressure. These results have important implications to the pathogenesis of PHA2 with WNK1 mutations.

Expression of apical Na(+)-L-glutamine co-transport activity, B(0)-system neutral amino acid co-transporter (B(0)AT1) and angiotensin-converting enzyme 2 along the jejunal crypt-villus axis in young pigs fed a liquid formula.

PubMed

Yang, Chengbo; Yang, Xiaojian; Lackeyram, Dale; Rideout, Todd C; Wang, Zirong; Stoll, Barbara; Yin, Yulong; Burrin, Douglas G; Fan, Ming Z

2016-06-01

Gut apical amino acid (AA) transport activity is high at birth and during suckling, thus being essential to maintain luminal nutrient-dependent mucosal growth through providing AA as essential metabolic fuel, substrates and nutrient stimuli for cellular growth. Because system-B(0) Na(+)-neutral AA co-transporter (B(0)AT1, encoded by the SLC6A19 gene) plays a dominant role for apical uptake of large neutral AA including L-Gln, we hypothesized that high apical Na(+)-Gln co-transport activity, and B(0)AT1 (SLC6A19) in co-expression with angiotensin-converting enzyme 2 (ACE2) were expressed along the entire small intestinal crypt-villus axis in young animals via unique control mechanisms. Kinetics of Na(+)-Gln co-transport activity in the apical membrane vesicles, prepared from epithelial cells sequentially isolated along the jejunal crypt-villus axis from liquid formula-fed young pigs, were measured with the membrane potential being clamped to zero using thiocyanate. Apical maximal Na(+)-Gln co-transport activity was much higher (p < 0.05) in the upper villus cells than in the middle villus (by 29 %) and the crypt (by 30 %) cells, whereas Na(+)-Gln co-transport affinity was lower (p < 0.05) in the upper villus cells than in the middle villus and the crypt cells. The B(0)AT1 (SLC6A19) mRNA abundance was lower (p < 0.05) in the crypt (by 40-47 %) than in the villus cells. There were no significant differences in B(0)AT1 and ACE2 protein abundances on the apical membrane among the upper villus, the middle villus and the crypt cells. Our study suggests that piglet fast growth is associated with very high intestinal apical Na(+)-neutral AA uptake activities via abundantly co-expressing B(0)AT1 and ACE2 proteins in the apical membrane and by transcribing the B(0)AT1 (SLC6A19) gene in the epithelia along the entire crypt-villus axis.

Signal transduction mechanisms of K+-Cl- cotransport regulation and relationship to disease.

PubMed

Adragna, N C; Ferrell, C M; Zhang, J; Di Fulvio, M; Temprana, C F; Sharma, A; Fyffe, R E W; Cool, D R; Lauf, P K

2006-01-01

The K+-Cl- cotransport (COT) regulatory pathways recently uncovered in our laboratory and their implication in disease state are reviewed. Three mechanisms of K+-Cl- COT regulation can be identified in vascular cells: (1) the Li+-sensitive pathway, (2) the platelet-derived growth factor (PDGF)-sensitive pathway and (3) the nitric oxide (NO)-dependent pathway. Ion fluxes, Western blotting, semi-quantitative RT-PCR, immunofluorescence and confocal microscopy were used. Li+, used in the treatment of manic depression, stimulates volume-sensitive K+-Cl- COT of low K+ sheep red blood cells at cellular concentrations <1 mM and inhibits at >3 mM, causes cell swelling, and appears to regulate K+-Cl- COT through a protein kinase C-dependent pathway. PDGF, a potent serum mitogen for vascular smooth muscle cells (VSMCs), regulates membrane transport and is involved in atherosclerosis. PDGF stimulates VSM K+-Cl- COT in a time- and concentration-dependent manner, both acutely and chronically, through the PDGF receptor. The acute effect occurs at the post-translational level whereas the chronic effect may involve regulation through gene expression. Regulation by PDGF involves the signalling molecules phosphoinositides 3-kinase and protein phosphatase-1. Finally, the NO/cGMP/protein kinase G pathway, involved in vasodilation and hence cardiovascular disease, regulates K+-Cl- COT in VSMCs at the mRNA expression and transport levels. A complex and diverse array of mechanisms and effectors regulate K+-Cl- COT and thus cell volume homeostasis, setting the stage for abnormalities at the genetic and/or regulatory level thus effecting or being affected by various pathological conditions.

KCNJ10 determines the expression of the apical Na-Cl cotransporter (NCC) in the early distal convoluted tubule (DCT1).

PubMed

Zhang, Chengbiao; Wang, Lijun; Zhang, Junhui; Su, Xiao-Tong; Lin, Dao-Hong; Scholl, Ute I; Giebisch, Gerhard; Lifton, Richard P; Wang, Wen-Hui

2014-08-12

The renal phenotype induced by loss-of-function mutations of inwardly rectifying potassium channel (Kir), Kcnj10 (Kir4.1), includes salt wasting, hypomagnesemia, metabolic alkalosis and hypokalemia. However, the mechanism by which Kir.4.1 mutations cause the tubulopathy is not completely understood. Here we demonstrate that Kcnj10 is a main contributor to the basolateral K conductance in the early distal convoluted tubule (DCT1) and determines the expression of the apical Na-Cl cotransporter (NCC) in the DCT. Immunostaining demonstrated Kcnj10 and Kcnj16 were expressed in the basolateral membrane of DCT, and patch-clamp studies detected a 40-pS K channel in the basolateral membrane of the DCT1 of p8/p10 wild-type Kcnj10(+/+) mice (WT). This 40-pS K channel is absent in homozygous Kcnj10(-/-) (knockout) mice. The disruption of Kcnj10 almost completely eliminated the basolateral K conductance and decreased the negativity of the cell membrane potential in DCT1. Moreover, the lack of Kcnj10 decreased the basolateral Cl conductance, inhibited the expression of Ste20-related proline-alanine-rich kinase and diminished the apical NCC expression in DCT. We conclude that Kcnj10 plays a dominant role in determining the basolateral K conductance and membrane potential of DCT1 and that the basolateral K channel activity in the DCT determines the apical NCC expression possibly through a Ste20-related proline-alanine-rich kinase-dependent mechanism.

Double Knockout of the Na+-Driven Cl−/HCO3− Exchanger and Na+/Cl− Cotransporter Induces Hypokalemia and Volume Depletion

PubMed Central

Sinning, Anne; Radionov, Nikita; Trepiccione, Francesco; López-Cayuqueo, Karen I.; Jayat, Maximilien; Baron, Stéphanie; Cornière, Nicolas; Alexander, R. Todd; Hadchouel, Juliette; Eladari, Dominique; Hübner, Christian A.

2017-01-01

We recently described a novel thiazide–sensitive electroneutral NaCl transport mechanism resulting from the parallel operation of the Cl−/HCO3− exchanger pendrin and the Na+–driven Cl−/2HCO3− exchanger (NDCBE) in β-intercalated cells of the collecting duct. Although a role for pendrin in maintaining Na+ balance, intravascular volume, and BP is well supported, there is no in vivo evidence for the role of NDCBE in maintaining Na+ balance. Here, we show that deletion of NDCBE in mice caused only subtle perturbations of Na+ homeostasis and provide evidence that the Na+/Cl− cotransporter (NCC) compensated for the inactivation of NDCBE. To unmask the role of NDCBE, we generated Ndcbe/Ncc double–knockout (dKO) mice. On a normal salt diet, dKO and single-knockout mice exhibited similar activation of the renin-angiotensin-aldosterone system, whereas only dKO mice displayed a lower blood K+ concentration. Furthermore, dKO mice displayed upregulation of the epithelial sodium channel (ENaC) and the Ca2+–activated K+ channel BKCa. During NaCl depletion, only dKO mice developed marked intravascular volume contraction, despite dramatically increased renin activity. Notably, the increase in aldosterone levels expected on NaCl depletion was attenuated in dKO mice, and single-knockout and dKO mice had similar blood K+ concentrations under this condition. In conclusion, NDCBE is necessary for maintaining sodium balance and intravascular volume during salt depletion or NCC inactivation in mice. Furthermore, NDCBE has an important role in the prevention of hypokalemia. Because NCC and NDCBE are both thiazide targets, the combined inhibition of NCC and the NDCBE/pendrin system may explain thiazide-induced hypokalemia in some patients. PMID:27151921

Pituitary control of branchial NCC, NKCC and Na(+), K (+)-ATPase α-subunit gene expression in Nile tilapia, Oreochromis niloticus.

PubMed

Breves, Jason P; Seale, Andre P; Moorman, Benjamin P; Lerner, Darren T; Moriyama, Shunsuke; Hopkins, Kevin D; Grau, E Gordon

2014-05-01

This study investigated endocrine control of branchial ionoregulatory function in Nile tilapia (Oreochromis niloticus) by prolactin (Prl188 and Prl177), growth hormone (Gh) and cortisol. Branchial expression of Na(+)/Cl(-) cotransporter (ncc) and Na(+)/K(+)/2Cl(-) cotransporter (nkcc) genes were employed as specific markers for freshwater- and seawater-type ionocytes, respectively. We further investigated whether Prl, Gh and cortisol direct expression of two Na(+), K(+)-ATPase (nka)-α1 subunit genes, denoted nka-α1a and nka-α1b. Tilapia transferred to fresh water following hypophysectomy failed to adequately activate gill ncc expression; ncc expression was subsequently restored by Prl replacement. Prl188 and Prl177 stimulated ncc expression in cultured gill filaments in a concentration-related manner, suggesting that ncc is regulated by Prl in a gill-autonomous fashion. Tilapia transferred to brackish water (23 ‰) following hypophysectomy exhibited a reduced capacity to up-regulate nka-α1b expression. However, Gh and cortisol failed to affect nka-α1b expression in vivo. Similarly, we found no clear effects of Gh or cortisol on nkcc expression both in vivo and in vitro. When considered with patterns previously described in euryhaline Mozambique tilapia (O. mossambicus), the current study suggests that ncc is a conserved target of Prl in tilapiine cichlids. In addition, we revealed contrasting dependencies upon the pituitary to direct nka-α1b expression in hyperosmotic environments between Nile and Mozambique tilapia.

Influence of salinity on the localization of Na+/K +-ATPase, Na+/K+/2Cl- cotransporter (NKCC) and CFTR anion channel in chloride cells of the Hawaiian goby (Stenogobius hawaiiensis)

USGS Publications Warehouse

McCormick, S.D.; Sundell, K.; Bjornsson, Bjorn Thrandur; Brown, C.L.; Hiroi, J.

2003-01-01

Na+/K+-ATPase, Na+/K+/2Cl- cotransporter (NKCC) and cystic fibrosis transmembrane conductance regulator (CFTR) are the three major transport proteins thought to be involved in chloride secretion in teleost fish. If this is the case, the levels of these transporters should be high in chloride cells of seawater-acclimated fish. We therefore examined the influence of salinity on immunolocalization of Na +/K+-ATPase, NKCC and CFTR in the gills of the Hawaiian goby (Stenogobius hawaiiensis). Fish were acclimated to freshwater and 20??? and 30??? seawater for 10 days. Na+/K +-ATPase and NKCC were localized specifically to chloride cells and stained throughout most of the cell except for the nucleus and the most apical region, indicating a basolateral/tubular distribution. All Na+/K +-ATPase-positive chloride cells were also positive for NKCC in all salinities. Salinity caused a slight increase in chloride cell number and size and a slight decrease in staining intensity for Na+/K +-ATPase and NKCC, but the basic pattern of localization was not altered. Gill Na+/K+-ATPase activity was also not affected by salinity. CFTR was localized to the apical surface of chloride cells, and only cells staining positive for Na+/K+-ATPase were CFTR-positive. CFTR-positive cells greatly increased in number (5-fold), area stained (53%) and intensity (29%) after seawater acclimation. In freshwater, CFTR immunoreactivity was light and occurred over a broad apical surface on chloride cells, whereas in seawater there was intense immunoreactivity around the apical pit (which was often punctate in appearance) and a light subapical staining. The results indicate that Na+/K +-ATPase, NKCC and CFTR are all present in chloride cells and support current models that all three are responsible for chloride secretion by chloride cells of teleost fish.

[New perspective on the role of WNK1 and WNK4 in the regulation of NaCl reabsorption and K(+) secretion by the distal nephron].

PubMed

Rafael, Chloé; Chavez-Canales, Maria; Hadchouel, Juliette

2016-03-01

The study of Familial Hyperkalemic Hypertension (FHHt), a rare monogenic disease, allowed remarkable advances in the understanding of the mechanisms of regulation of NaCl reabsorption by the distal nephron. FHHt results from mutations in the genes encoding WNK1 and WNK4, two serine-threonine kinases of the WNK (With No lysine [K]) family. The clinical manifestations of FHHt are due, among others, to an increased activity of the Na(+)-Cl(-) cotransporter NCC. Several groups therefore tried to understand how WNK1 and WNK4 could regulate NCC. However, the data were often contradictory. Two of our recent studies allowed to partially explain these controversies and to propose a new model for the regulation of NCC by the WNKs. © 2016 médecine/sciences – Inserm.

Long-term aldosterone administration increases renal Na+-Cl- cotransporter abundance in late distal convoluted tubule.

PubMed

Poulsen, Søren Brandt; Christensen, Birgitte Mønster

2017-09-01

Renal Na + -Cl - cotransporter (NCC) is expressed in early distal convoluted tubule (DCT) 1 and late DCT (DCT2). NCC activity can be stimulated by aldosterone administration, and the mechanism is assumed to depend on the enzyme 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2), which inactivates glucocorticoids that would otherwise occupy aldosterone receptors. Because 11β-HSD2 in rat may only be abundantly expressed in DCT2 cells and not in DCT1 cells, it has been speculated that aldosterone specifically stimulates NCC activity in DCT2 cells. In mice, however, it is debated if 11β-HSD2 is expressed in DCT2 cells. The present study examined whether aldosterone administration in mice stimulates NCC abundance and phosphorylation in DCT2 cells but not in DCT1 cells. B6/C57 male mice were administered 100 µg aldosterone·kg body weight -1 ·24 h -1 for 6 days and euthanized during isoflurane inhalation. Western blotting of whole kidney homogenate showed that aldosterone administration stimulated NCC and pT58-NCC abundances ( P < 0.001). In DCT1 cells, confocal microscopy detected no effect of the aldosterone administration on NCC and pT58-NCC abundances. By contrast, NCC and pT58-NCC abundances were stimulated by aldosterone administration in the middle of DCT2 ( P < 0.001 and <0.01, respectively) and at the junction between DCT2 and CNT ( P < 0.001 and <0.05, respectively). In contrast to rat, immunohistochemistry in mouse showed no/very weak 11β-HSD2 expression in DCT2 cells. Collectively, long-term aldosterone administration stimulates mouse NCC and pT58-NCC abundances in DCT2 cells and presumably not in DCT1 cells. Copyright © 2017 the American Physiological Society.

Human NKCC2 cation–Cl– co-transporter complements lack of Vhc1 transporter in yeast vacuolar membranes.

PubMed

Petrezselyova, Silvia; Dominguez, Angel; Herynkova, Pavla; Macias, Juan F; Sychrova, Hana

2013-10-01

Cation–chloride co-transporters serve to transport Cl– and alkali metal cations. Whereas a large family of these exists in higher eukaryotes, yeasts only possess one cation–chloride co-transporter, Vhc1, localized to the vacuolar membrane. In this study, the human cation–chloride co-transporter NKCC2 complemented the phenotype of VHC1 deletion in Saccharomyces cerevisiae and its activity controlled the growth of salt-sensitive yeast cells in the presence of high KCl, NaCl and LiCl. A S. cerevisiae mutant lacking plasma-membrane alkali–metal cation exporters Nha1 and Ena1-5 and the vacuolar cation–chloride co-transporter Vhc1 is highly sensitive to increased concentrations of alkali–metal cations, and it proved to be a suitable model for characterizing the substrate specificity and transport activity of human wild-type and mutated cation–chloride co-transporters. Copyright © 2013 John Wiley & Sons, Ltd.

Regulation of the renal Na+-Cl− cotransporter by phosphorylation and ubiquitylation

PubMed Central

2012-01-01

The activity of the renal thiazide-sensitive NaCl cotransporter (NCC) in the distal convoluted tubule plays a key role in defining arterial blood pressure levels. Increased or decreased activity of the NCC is associated with arterial hypertension or hypotension, respectively. Thus it is of major interest to understand the activity of NCC using in vivo models. Phosphorylation of certain residues of the amino-terminal domain of NCC has been shown to be associated with its activation. The development of phospho-specific antibodies against these sites provides a powerful tool that is helping to increase our understanding of the molecular physiology of NCC. Additionally, NCC expression in the plasma membrane is modulated by ubiquitylation, which represents another major mechanism for regulating protein activity. This work presents a review of our current knowledge of the regulation of NCC activity by phosphorylation and ubiquitylation. PMID:23034942

Acute hypertension provokes acute trafficking of distal tubule Na-Cl cotransporter (NCC) to subapical cytoplasmic vesicles.

PubMed

Lee, Donna H; Riquier, Anne D M; Yang, Li E; Leong, Patrick K K; Maunsbach, Arvid B; McDonough, Alicia A

2009-04-01

When blood pressure (BP) is elevated above baseline, a pressure natriuresis-diuresis response ensues, critical to volume and BP homeostasis. Distal convoluted tubule Na(+)-Cl(-) cotransporter (NCC) is regulated by trafficking between the apical plasma membrane (APM) and subapical cytoplasmic vesicles (SCV). We aimed to determine whether NCC trafficking contributes to pressure diuresis by decreasing APM NCC or compensates for increased volume flow to the DCT by increasing APM NCC. BP was raised 50 mmHg (high BP) in rats by arterial constriction for 5 or 20-30 min, provoking a 10-fold diuresis at both times. Kidneys were excised, and NCC subcellular distribution was analyzed by 1) sorbitol density gradient fractionation and immunoblotting and 2) immunoelectron microscopy (immuno-EM). NCC distribution did not change after 5-min high BP. After 20-30 min of high BP, 20% of NCC redistributed from low-density, APM-enriched fractions to higher density, endosome-enriched fractions, and, by quantitative immuno-EM, pool size of APM NCC decreased 14% and SCV pool size increased. Because of the time lag of the response, we tested the hypothesis that internalization of NCC was secondary to the decrease in ANG II that accompanies high BP. Clamping ANG II at a nonpressor level by coinfusion of captopril (12 microg/min) and ANG II (20 ng.kg(-1).min(-1)) during 30-min high BP reduced diuresis to eightfold and prevented redistribution of NCC from APM- to SCV-enriched fractions. We conclude that DCT NCC may participate in pressure natriuresis-diuresis by retraction out of apical plasma membranes and that the retraction is, at least in part, driven by the fall in ANG II that accompanies acute hypertension.

Effects of ACE inhibition and ANG II stimulation on renal Na-Cl cotransporter distribution, phosphorylation, and membrane complex properties

PubMed Central

Lee, Donna H.; Maunsbach, Arvid B.; Riquier-Brison, Anne D.; Nguyen, Mien T. X.; Fenton, Robert A.; Bachmann, Sebastian; Yu, Alan S.

2013-01-01

The renal distal tubule Na-Cl cotransporter (NCC) reabsorbs <10% of the filtered Na+ but is a key control point for blood pressure regulation by angiotensin II (ANG II), angiotensin-converting enzyme inhibitors (ACEI), and thiazide diuretics. This study aimed to determine whether NCC phosphorylation (NCCp) was regulated by acute (20–30 min) treatment with the ACEI captopril (12 μg/min × 20 min) or by a sub-pressor dose of ANG II (20 ng·kg−1·min−1) in Inactin-anesthetized rats. By immuno-EM, NCCp was detected exclusively in or adjacent to apical plama membranes (APM) in controls and after ACEI or ANG II treatment, while NCC total was detected in both APM and subapical cytoplasmic vesicles (SCV) in all conditions. In renal homogenates, neither ACEI nor ANG II treatment altered NCCp abundance, assayed by immunoblot. However, by density gradient fractionation we identified a pool of low-density APM in which NCCp decreased 50% in response to captopril and was restored during ANG II infusion, and another pool of higher-density APM that responded reciprocally, indicative of regulated redistribution between two APM pools. In both pools, NCCp was preferentially localized to Triton-soluble membranes. Blue Native gel electrophoresis established that APM NCCp localized to ∼700 kDa complexes (containing γ-adducin) while unphosphorylated NCC in intracellular membranes primarily localized to ∼400 kDa complexes: there was no evidence for native monomeric or dimeric NCC or NCCp. In summary, this study demonstrates that phosphorylated NCC, localized to multimeric complexes in the APM, redistributes in a regulated manner within the APM in response to ACEI and ANG II. PMID:23114965

Isotonic transport by the Na+-glucose cotransporter SGLT1 from humans and rabbit

PubMed Central

Zeuthen, T; Meinild, A-K; Loo, D D F; Wright, E M; Klaerke, D A

2001-01-01

In order to study its role in steady state water transport, the Na+-glucose cotransporter (SGLT1) was expressed in Xenopus laevis oocytes; both the human and the rabbit clones were tested. The transport activity was monitored as a clamp current and the flux of water followed optically as the change in oocyte volume. SGLT1 has two modes of water transport. First, it acts as a molecular water pump: for each 2 Na+ and 1 sugar molecule 264 water molecules were cotransported in the human SGLT1 (hSGLT1), 424 for the rabbit SGLT1 (rSGLT1). Second, it acts as a water channel. The cotransport of water was tightly coupled to the sugar-induced clamp current. Instantaneous changes in clamp current induced by changes in clamp voltage were accompanied by instantaneous changes in the rate of water transport. The cotransported solution was predicted to be hypertonic, and an osmotic gradient built up across the oocyte membrane with continued transport; this resulted in an additional osmotic influx of water. After 5-10 min a steady state was achieved in which the total influx was predicted to be isotonic with the intracellular solution. With the given expression levels, the steady state water transport was divided about equally between cotransport, osmosis across the SGLT1 and osmosis across the native oocyte membrane. Coexpression of AQP1 with the SGLT1 increased the water permeability more than 10-fold and steady state isotonic transport was achieved after less than 2 s of sugar activation. One-third of the water was cotransported, and the remainder was osmotically driven through the AQP1. The data suggest that SGLT1 has three roles in isotonic water transport: it cotransports water directly, it supplies a passive pathway for osmotic water transport, and it generates an osmotic driving force that can be employed by other pathways, for example aquaporins. PMID:11251046

Regulated phosphorylation of the K-Cl cotransporter KCC3 is a molecular switch of intracellular potassium content and cell volume homeostasis

PubMed Central

Adragna, Norma C.; Ravilla, Nagendra B.; Lauf, Peter K.; Begum, Gulnaz; Khanna, Arjun R.; Sun, Dandan; Kahle, Kristopher T.

2015-01-01

The defense of cell volume against excessive shrinkage or swelling is a requirement for cell function and organismal survival. Cell swelling triggers a coordinated homeostatic response termed regulatory volume decrease (RVD), resulting in K+ and Cl− efflux via activation of K+ channels, volume-regulated anion channels (VRACs), and the K+-Cl− cotransporters, including KCC3. Here, we show genetic alanine (Ala) substitution at threonines (Thr) 991 and 1048 in the KCC3a isoform carboxyl-terminus, preventing inhibitory phosphorylation at these sites, not only significantly up-regulates KCC3a activity up to 25-fold in normally inhibitory isotonic conditions, but is also accompanied by reversal of activity of the related bumetanide-sensitive Na+-K+-2Cl− cotransporter isoform 1 (NKCC1). This results in a rapid (<10 min) and significant (>90%) reduction in intracellular K+ content (Ki) via both Cl-dependent (KCC3a + NKCC1) and Cl-independent [DCPIB (VRAC inhibitor)-sensitive] pathways, which collectively renders cells less prone to acute swelling in hypotonic osmotic stress. Together, these data demonstrate the phosphorylation state of Thr991/Thr1048 in KCC3a encodes a potent switch of transporter activity, Ki homeostasis, and cell volume regulation, and reveal novel observations into the functional interaction among ion transport molecules involved in RVD. PMID:26217182

KCl cotransport regulation and protein kinase G in cultured vascular smooth muscle cells.

PubMed

Adragna, N C; Zhang, J; Di Fulvio, M; Lincoln, T M; Lauf, P K

2002-05-15

K-Cl cotransport is activated by vasodilators in erythrocytes and vascular smooth muscle cells and its regulation involves putative kinase/phosphatase cascades. N-ethylmaleimide (NEM) activates the system presumably by inhibiting a protein kinase. Nitrovasodilators relax smooth muscle via cGMP-dependent activation of protein kinase G (PKG), a regulator of membrane channels and transporters. We investigated whether PKG regulates K-Cl cotransport activity or mRNA expression in normal, PKG-deficient-vector-only-transfected (PKG-) and PKG-catalytic-domain-transfected (PKG+) rat aortic smooth muscle cells. K-Cl cotransport was calculated as the Cl-dependent Rb influx, and mRNA was determined by semiquantitative RT-PCR. Baseline K-Cl cotransport was higher in PKG+ than in PKG- cells (p <0.01). At 0.5 mM, NEM stimulated K-Cl cotransport by 5-fold in PKG- but not in PKG+ cells. However, NEM was more potent although less effective to activate K-Cl cotransport in normal (passage 1-3) and PKG+ than in PKG- cells. In PKG- cells, [(dihydroindenyl) oxy] alkanoic acid (300 mM) but not furosemide (1 mM) inhibited K-Cl cotransport. Furthermore, no difference in K-Cl cotransport mRNA expression was observed between these cells. In conclusion, this study shows that manipulation of PKG expression in vascular smooth muscle cells affects K-Cl cotransport activity and its activation by NEM.

NaCl-Induced Alterations in Both Cell Structure and Tissue-Specific Plasma Membrane H+ -ATPase Gene Expression.

PubMed Central

Niu, X.; Damsz, B.; Kononowicz, A. K.; Bressan, R. A.; Hasegawa, P. M.

1996-01-01

NaCl-induced plasma membrane H+-ATPase gene expression, which occurs in roots and fully expanded leaves of the halophyte Atriplex nummularia L. (X. Niu, M.L. Narasimhan, R.A. Salzman, R.A. Bressan, P.M. Hasegawa [1993] Plant Physiol 103: 713-718), has been differentially localized to specific tissues using in situ RNA hybridization techniques. Twenty-four-hour exposure of plants to 400 mM NaCl resulted in substantial accumulation of H+ pump message in the epidermis of the root tip and the endodermis of the root elongation/differentiation zone. In expanded leaves, NaCl induction of plasma membrane H+-ATPase message accumulation was localized to bundle-sheath cells. Ultrastructural analyses indicated that significant cytological adaptations in root cells included plasmolysis that is accompanied by plasma membrane invaginations, formation of Hechtian strands and vesiculation, and vacuolation. These results identify specific tissues that are involved in the regulation of Na+ and Cl- uptake into different organs of the halophyte A. nummularia and provide evidence of the intercellular and interorgan coordination that occurs in the mediation of NaCl adaptation. PMID:12226321

NaCl-Induced Alterations in Both Cell Structure and Tissue-Specific Plasma Membrane H+ -ATPase Gene Expression.

PubMed

Niu, X.; Damsz, B.; Kononowicz, A. K.; Bressan, R. A.; Hasegawa, P. M.

1996-07-01

NaCl-induced plasma membrane H+-ATPase gene expression, which occurs in roots and fully expanded leaves of the halophyte Atriplex nummularia L. (X. Niu, M.L. Narasimhan, R.A. Salzman, R.A. Bressan, P.M. Hasegawa [1993] Plant Physiol 103: 713-718), has been differentially localized to specific tissues using in situ RNA hybridization techniques. Twenty-four-hour exposure of plants to 400 mM NaCl resulted in substantial accumulation of H+ pump message in the epidermis of the root tip and the endodermis of the root elongation/differentiation zone. In expanded leaves, NaCl induction of plasma membrane H+-ATPase message accumulation was localized to bundle-sheath cells. Ultrastructural analyses indicated that significant cytological adaptations in root cells included plasmolysis that is accompanied by plasma membrane invaginations, formation of Hechtian strands and vesiculation, and vacuolation. These results identify specific tissues that are involved in the regulation of Na+ and Cl- uptake into different organs of the halophyte A. nummularia and provide evidence of the intercellular and interorgan coordination that occurs in the mediation of NaCl adaptation.

Characterization of an extracellular epitope antibody to the neuronal K-Cl cotransporter, KCC2.

PubMed

Gagnon, Kenneth Be; Fyffe, Robert Ew; Adragna, Norma C; Lauf, Peter K

2007-07-01

1. Ion gradients across the cell membrane are important for proper cellular communication and homeostasis. With the exception of erythrocytes, chloride (Cl), one of the most important free anions in animal cells, is not distributed at thermodynamic equilibrium across the plasma membrane. The K-Cl cotransporter (COT), consisting of at least four isoforms, utilizes the larger outwardly directed chemical driving force of K to expel Cl from the cell against its inwardly directed chemical gradient and has been implicated recently as one of the main Cl extruders in developing neurons. 2. Previous in situ hybridization studies have indicated widespread mRNA distribution of the neuronal-specific K-Cl COT isoform (KCC2) throughout the rat central nervous system (CNS). However, immunohistochemical studies have been limited owing to the availability of a more selective antibody to KCC2. The goal of the present study was to develop a new molecular tool for the immunohistochemical identification and neuronal distribution of KCC2. 3. Herein, we present evidence of immunohistochemical corroboration of the widespread KCC2 mRNA expression using a novel extracellular anti-peptide antibody directed against the second extracellular loop (ECL2) of KCC2. Immunoperoxidase and immunofluorescent labelling revealed widespread post-synaptic somatic and dendritic localization of KCC2 in multiple neuronal populations in the cerebral cortex, hippocampus, brainstem, lumbar spinal cord and cerebellum. We also demonstrate that binding of the antibody to an extracellular epitope within ECL2 does not alter cotransporter function. In essence, the present study reports on a new molecular tool for structural and functional studies of KCC2.

Postnatal Changes in K+/Cl- Cotransporter-2 Expression in the Forebrain of Mice Bearing a Mutant Nicotinic Subunit Linked to Sleep-Related Epilepsy.

PubMed

Amadeo, Alida; Coatti, Aurora; Aracri, Patrizia; Ascagni, Miriam; Iannantuoni, Davide; Modena, Debora; Carraresi, Laura; Brusco, Simone; Meneghini, Simone; Arcangeli, Annarosa; Pasini, Maria Enrica; Becchetti, Andrea

2018-06-24

The Na + /K + /Cl - cotransporter-1 (NKCC1) and the K + /Cl - cotransporter-2 (KCC2) set the transmembrane Cl - gradient in the brain, and are implicated in epileptogenesis. We studied the postnatal distribution of NKCC1 and KCC2 in wild-type (WT) mice, and in a mouse model of sleep-related epilepsy, carrying the mutant β2-V287L subunit of the nicotinic acetylcholine receptor (nAChR). In WT neocortex, immunohistochemistry showed a wide distribution of NKCC1 in neurons and astrocytes. At birth, KCC2 was localized in neuronal somata, whereas at subsequent stages it was mainly found in the somatodendritic compartment. The cotransporters' expression was quantified by densitometry in the transgenic strain. KCC2 expression increased during the first postnatal weeks, while the NKCC1 amount remained stable, after birth. In mice expressing β2-V287L, the KCC2 amount in layer V of prefrontal cortex (PFC) was lower than in the control littermates at postnatal day 8 (P8), with no concomitant change in NKCC1. Consistently, the GABAergic excitatory to inhibitory switch was delayed in PFC layer V of mice carrying β2-V287L. At P60, the amount of KCC2 was instead higher in mice bearing the transgene. Irrespective of genotype, NKCC1 and KCC2 were abundantly expressed in the neuropil of most thalamic nuclei since birth. However, KCC2 expression decreased by P60 in the reticular nucleus, and more so in mice expressing β2-V287L. Therefore, a complex regulatory interplay occurs between heteromeric nAChRs and KCC2 in postnatal forebrain. The pathogenetic effect of β2-V287L may depend on altered KCC2 amounts in PFC during synaptogenesis, as well as in mature thalamocortical circuits. Copyright © 2018. Published by Elsevier Ltd.

Localization of a renal sodium-phosphate cotransporter gene to human chromosome 5q35

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kos, C.H.; Tenenhouse, H.S.; Tihy, F.

1994-01-01

Several Mendelian disorders of renal phosphate reabsorption, associated with hypophosphatemia and bone disease, have been described. These include X-linked hypophosphatemia (XLH), hereditary hypophosphatemic rickets with hypercalciuria, hypophosphatemic bone disease, and autosomal dominant and autosomal recessive hypophosphatemic rickets. The underlying mechanisms for renal phosphate wasting in these disorders remain unknown. The proximal tubule is the major site of renal phosphate reabsorption. Thus, mutations in genes that participate in the transepithelial transport of phosphate in this segment of the nephron may be responsible for these disorders. Recently, a cDNA encoding a renal proximal tubular, brush-border membrane Na[sup +]-phosphate cotransporter (NaP[sub i]-3) wasmore » cloned from human kidney cortex. As a first step in establishing whether mutations in the NaP[sub i]-3 gene are the cause of inherited disorders in phosphate homeostasis, the authors sought to determine its chromosomal localization. 9 refs., 1 fig.« less

Renal Dysfunction Induced by Kidney-Specific Gene Deletion of Hsd11b2 as a Primary Cause of Salt-Dependent Hypertension.

PubMed

Ueda, Kohei; Nishimoto, Mitsuhiro; Hirohama, Daigoro; Ayuzawa, Nobuhiro; Kawarazaki, Wakako; Watanabe, Atsushi; Shimosawa, Tatsuo; Loffing, Johannes; Zhang, Ming-Zhi; Marumo, Takeshi; Fujita, Toshiro

2017-07-01

Genome-wide analysis of renal sodium-transporting system has identified specific variations of Mendelian hypertensive disorders, including HSD11B2 gene variants in apparent mineralocorticoid excess. However, these genetic variations in extrarenal tissue can be involved in developing hypertension, as demonstrated in former studies using global and brain-specific Hsd11b2 knockout rodents. To re-examine the importance of renal dysfunction on developing hypertension, we generated kidney-specific Hsd11b2 knockout mice. The knockout mice exhibited systemic hypertension, which was abolished by reducing salt intake, suggesting its salt-dependency. In addition, we detected an increase in renal membrane expressions of cleaved epithelial sodium channel-α and T53-phosphorylated Na + -Cl - cotransporter in the knockout mice. Acute intraperitoneal administration of amiloride-induced natriuresis and increased urinary sodium/potassium ratio more in the knockout mice compared with those in the wild-type control mice. Chronic administration of amiloride and high-KCl diet significantly decreased mean blood pressure in the knockout mice, which was accompanied with the correction of hypokalemia and the resultant decrease in Na + -Cl - cotransporter phosphorylation. Accordingly, a Na + -Cl - cotransporter blocker hydrochlorothiazide significantly decreased mean blood pressure in the knockout mice. Chronic administration of mineralocorticoid receptor antagonist spironolactone significantly decreased mean blood pressure of the knockout mice along with downregulation of cleaved epithelial sodium channel-α and phosphorylated Na + -Cl - cotransporter expression in the knockout kidney. Our data suggest that kidney-specific deficiency of 11β-HSD2 leads to salt-dependent hypertension, which is attributed to mineralocorticoid receptor-epithelial sodium channel-Na + -Cl - cotransporter activation in the kidney, and provides evidence that renal dysfunction is essential for developing the

Natural variability in Drosophila larval and pupal NaCl tolerance.

PubMed

Riedl, Craig A L; Oster, Sara; Busto, Macarena; Mackay, Trudy F C; Sokolowski, Marla B

2016-05-01

The regulation of NaCl is essential for the maintenance of cellular tonicity and functionality, and excessive salt exposure has many adverse effects. The fruit fly, Drosophila melanogaster, is a good osmoregulator and some strains can survive on media with very low or high NaCl content. Previous analyses of mutant alleles have implicated various stress signaling cascades in NaCl sensitivity or tolerance; however, the genes influencing natural variability of NaCl tolerance remain for the most part unknown. Here, we use two approaches to investigate natural variation in D. melanogaster NaCl tolerance. We describe four D. melanogaster lines that were selected for different degrees of NaCl tolerance, and present data on their survival, development, and pupation position when raised on varying NaCl concentrations. After finding evidence for natural variation in salt tolerance, we present the results of Quantitative Trait Loci (QTL) mapping of natural variation in larval and pupal NaCl tolerance, and identify different genomic regions associated with NaCl tolerance during larval and pupal development. Copyright © 2016 Elsevier Ltd. All rights reserved.

Involvement of a Na+/HCO-3 cotransporter in mouse sperm capacitation.

PubMed

Demarco, Ignacio A; Espinosa, Felipe; Edwards, Jennifer; Sosnik, Julian; De La Vega-Beltran, Jose Luis; Hockensmith, Joel W; Kopf, Gregory S; Darszon, Alberto; Visconti, Pablo E

2003-02-28

Mammalian sperm are incapable of fertilizing eggs immediately after ejaculation; they acquire fertilization capacity after residing in the female tract for a finite period of time. The physiological changes sperm undergo in the female reproductive tract that render sperm able to fertilize constitute the phenomenon of "sperm capacitation." We have demonstrated that capacitation is associated with an increase in the tyrosine phosphorylation of a subset of proteins and that these events are regulated by an HCO(3)(-)/cAMP-dependent pathway involving protein kinase A. Capacitation is also accompanied by hyperpolarization of the sperm plasma membrane. Here we present evidence that, in addition to its role in the regulation of adenylyl cyclase, HCO(3)(-) has a role in the regulation of plasma membrane potential in mouse sperm. Addition of HCO(3)(-) but not Cl(-) induces a hyperpolarizing current in mouse sperm plasma membranes. This HCO(3)(-)-dependent hyperpolarization was not observed when Na(+) was replaced by the non-permeant cation choline(+). Replacement of Na(+) by choline(+) also inhibited the capacitation-associated increase in protein tyrosine phosphorylation as well as the zona pellucida-induced acrosome reaction. The lack of an increase in protein tyrosine phosphorylation was overcome by the presence of cAMP agonists in the incubation medium. The lack of a hyperpolarizing HCO(3)(-) current and the inhibition of the capacitation-dependent increase in protein tyrosine phosphorylation in the absence of Na(+) suggest that a Na(+)/HCO(3)(-) cotransporter is present in mouse sperm and is coupled to events regulating capacitation.

Mutation of the Na(+)-K(+)-2Cl(-) cotransporter NKCC2 in mice is associated with severe polyuria and a urea-selective concentrating defect without hyperreninemia.

PubMed

Kemter, Elisabeth; Rathkolb, Birgit; Bankir, Lise; Schrewe, Anja; Hans, Wolfgang; Landbrecht, Christina; Klaften, Matthias; Ivandic, Boris; Fuchs, Helmut; Gailus-Durner, Valérie; Hrabé de Angelis, Martin; Wolf, Eckhard; Wanke, Ruediger; Aigner, Bernhard

2010-06-01

The bumetanide-sensitive Na(+)-K(+)-2Cl(-) cotransporter NKCC2, located in the thick ascending limb of Henle's loop, plays a critical role in the kidney's ability to concentrate urine. In humans, loss-of-function mutations of the solute carrier family 12 member 1 gene (SLC12A1), coding for NKCC2, cause type I Bartter syndrome, which is characterized by prenatal onset of a severe polyuria, salt-wasting tubulopathy, and hyperreninemia. In this study, we describe a novel chemically induced, recessive mutant mouse line termed Slc12a1(I299F) exhibiting late-onset manifestation of type I Bartter syndrome. Homozygous mutant mice are viable and exhibit severe polyuria, metabolic alkalosis, marked increase in plasma urea but close to normal creatininemia, hypermagnesemia, hyperprostaglandinuria, hypotension,, and osteopenia. Fractional excretion of urea is markedly decreased. In addition, calcium and magnesium excretions are more than doubled compared with wild-type mice, while uric acid excretion is twofold lower. In contrast to hyperreninemia present in human disease, plasma renin concentration in homozygotes is not increased. The polyuria observed in homozygotes may be due to the combination of two additive factors, a decrease in activity of mutant NKCC2 and an increase in medullary blood flow, due to prostaglandin-induced vasodilation, that impairs countercurrent exchange of urea in the medulla. In conclusion, this novel viable mouse line with a missense Slc12a1 mutation exhibits most of the features of type I Bartter syndrome and may represent a new model for the study of this human disease.

Bumetanide increases Cl--dependent short-circuit current in late distal colon: Evidence for the presence of active electrogenic Cl- absorption.

PubMed

Tang, Lieqi; Fang, Xiefan; Winesett, Steven P; Cheng, Catherine Y; Binder, Henry J; Rivkees, Scott A; Cheng, Sam X

2017-01-01

Mammalian colonic epithelia consist of cells that are capable of both absorbing and secreting Cl-. The present studies employing Ussing chamber technique identified two opposing short-circuit current (Isc) responses to basolateral bumetanide in rat distal colon. Apart from the transepithelial Cl--secretory Isc in early distal colon that was inhibited by bumetanide, bumetanide also stimulated Isc in late distal colon that had not previously been identified. Since bumetanide inhibits basolateral Na+-K+-2Cl- cotransporter (NKCC) in crypt cells and basolateral K+-Cl- cotransporter (KCC) in surface epithelium, we proposed this stimulatory Isc could represent a KCC-mediated Cl- absorptive current. In support of this hypothesis, ion substitution experiments established Cl- dependency of this absorptive Isc and transport inhibitor studies demonstrated the involvement of an apical Cl- conductance. Current distribution and RNA sequencing analyses revealed that this Cl- absorptive Isc is closely associated with epithelial Na+ channel (ENaC) but is not dependent on ENaC activity. Thus, inhibition of ENaC by 10 μM amiloride or benzamil neither altered the direction nor its activity. Physiological studies suggested that this Cl- absorptive Isc senses dietary Cl- content; thus when dietary Cl- was low, Cl- absorptive Isc was up-regulated. In contrast, when dietary Cl- was increased, Cl- absorptive Isc was down-regulated. We conclude that an active Cl- extrusion mechanism exists in ENaC-expressing late distal colon and likely operates in parallel with ENaC to facilitate NaCl absorption.

Long-term myocardial preservation: beneficial and additive effects of polarized arrest (Na+-channel blockade), Na+/H+-exchange inhibition, and Na+/K+/2Cl- -cotransport inhibition combined with calcium desensitization.

PubMed

Snabaitis, A K; Chambers, D

1999-11-27

Polarized arrest, induced by tetrodotoxin (TTX) at an optimal concentration of 22 micromol/L, has been shown to reduce ionic imbalance and improve myocardial preservation compared with hyperkalemic (depolarized) arrest. Additional pharmacologic manipulation of ionic changes (involving inhibition of Na+ influx by the Na+/H+ exchanger [HOE694] and Na+/K+/2Cl- cotransporter [furosemide], and calcium desensitization [BDM]) may further improve long-term preservation. In this study, we (i) established optimal concentrations of each drug, (ii) determined additive effects of optimal concentrations of each drug and (iii) compared our optimal preservation solution to an established depolarizing cardioplegia (St Thomas' Hospital solution No 2: STH2) used during long-term hypothermic storage for clinical transplantation. The isolated working rat heart, perfused with Krebs Henseleit (KH) buffer was used; cardiac function was measured after 20 min aerobic working mode perfusion. The hearts (n=6/group) were arrested with a 2 ml infusion (for 30 sec) of the polarizing (control) solution (22 micromol/L TTX in KH) or control+drug and subjected to 5 hr or 8 hr of storage at 7.5 degrees C in the arresting solution. Postischemic function during reperfusion was measured (expressed as percentage of preischemic function). Dose-response studies established optimal concentrations of HOE694 (10 micromol/L), furosemide (1.0 micromol/L) and BDM (30 mmol/L) in the polarizing (control) solution. Sequential addition to the control solution (Group I) of optimal concentrations of HOE694 (Group II), furosemide (Group III), and BDM (Group IV) were compared with STH2 (Group V); postischemic recovery of aortic flow was 29+/-7%, 49+/-6%*, 56+/-2%*, 76+/-3%*, and 25+/-6%, respectively (*P<0.05 vs. I and V). Creatine kinase leakage was lowest, and myocardial ATP content was highest in Group IV. A polarizing preservation solution (KH+TTX) containing HOE694, furosemide, and BDM significantly enhanced long

Characterization of NaCl tolerance in Desulfovibrio vulgaris Hildenborough through experimental evolution

PubMed Central

Zhou, Aifen; Baidoo, Edward; He, Zhili; Mukhopadhyay, Aindrila; Baumohl, Jason K; Benke, Peter; Joachimiak, Marcin P; Xie, Ming; Song, Rong; Arkin, Adam P; Hazen, Terry C; Keasling, Jay D; Wall, Judy D; Stahl, David A; Zhou, Jizhong

2013-01-01

Desulfovibrio vulgaris Hildenborough strains with significantly increased tolerance to NaCl were obtained via experimental evolution. A NaCl-evolved strain, ES9-11, isolated from a population cultured for 1200 generations in medium amended with 100 mM NaCl, showed better tolerance to NaCl than a control strain, EC3-10, cultured for 1200 generations in parallel but without NaCl amendment in medium. To understand the NaCl adaptation mechanism in ES9-11, we analyzed the transcriptional, metabolite and phospholipid fatty acid (PLFA) profiles of strain ES9-11 with 0, 100- or 250 mM-added NaCl in medium compared with the ancestral strain and EC3-10 as controls. In all the culture conditions, increased expressions of genes involved in amino-acid synthesis and transport, energy production, cation efflux and decreased expression of flagellar assembly genes were detected in ES9-11. Consistently, increased abundances of organic solutes and decreased cell motility were observed in ES9-11. Glutamate appears to be the most important osmoprotectant in D. vulgaris under NaCl stress, whereas, other organic solutes such as glutamine, glycine and glycine betaine might contribute to NaCl tolerance under low NaCl concentration only. Unsaturation indices of PLFA significantly increased in ES9-11. Branched unsaturated PLFAs i17:1 ω9c, a17:1 ω9c and branched saturated i15:0 might have important roles in maintaining proper membrane fluidity under NaCl stress. Taken together, these data suggest that the accumulation of osmolytes, increased membrane fluidity, decreased cell motility and possibly an increased exclusion of Na+ contribute to increased NaCl tolerance in NaCl-evolved D. vulgaris. PMID:23575373

The Role of Na:K:2Cl Cotransporter 1 (NKCC1/SLC12A2) in Dental Epithelium during Enamel Formation in Mice

PubMed Central

Jalali, Rozita; Lodder, Johannes C.; Zandieh-Doulabi, Behrouz; Micha, Dimitra; Melvin, James E.; Catalan, Marcelo A.; Mansvelder, Huibert D.; DenBesten, Pamela; Bronckers, Antonius

2017-01-01

Na+:K+:2Cl− cotransporters (NKCCs) belong to the SLC12A family of cation-coupled Cl− transporters. We investigated whether enamel-producing mouse ameloblasts express NKCCs. Transcripts for Nkcc1 were identified in the mouse dental epithelium by RT-qPCR and NKCC1 protein was immunolocalized in outer enamel epithelium and in the papillary layer but not the ameloblast layer. In incisors of Nkcc1-null mice late maturation ameloblasts were disorganized, shorter and the mineral density of the enamel was reduced by 10% compared to wild-type controls. Protein levels of gap junction protein connexin 43, Na+-dependent bicarbonate cotransporter e1 (NBCe1), and the Cl−-dependent bicarbonate exchangers SLC26A3 and SLC26A6 were upregulated in Nkcc1-null enamel organs while the level of NCKX4/SLC24A4, the major K+, Na+ dependent Ca2+ transporter in maturation ameloblasts, was slightly downregulated. Whole-cell voltage clamp studies on rat ameloblast-like HAT-7 cells indicated that bumetanide increased ion-channel activity conducting outward currents. Bumetanide also reduced cell volume of HAT-7 cells. We concluded that non-ameloblast dental epithelium expresses NKCC1 to regulate cell volume in enamel organ and provide ameloblasts with Na+, K+ and Cl− ions required for the transport of mineral- and bicarbonate-ions into enamel. Absence of functional Nkcc1 likely is compensated by other types of ion channels and ion transporters. The increased amount of Cx43 in enamel organ cells in Nkcc1-null mice suggests that these cells display a higher number of gap junctions to increase intercellular communication. PMID:29209227

Functional classification of mitochondrion-rich cells in euryhaline Mozambique tilapia (Oreochromis mossambicus) embryos, by means of triple immunofluorescence staining for Na+/K+-ATPase, Na +/K+/2Cl- cotransporter and CFTR anion channel

USGS Publications Warehouse

Hiroi, J.; McCormick, S.D.; Ohtani-Kaneko, R.; Kaneko, T.

2005-01-01

Mozambique tilapia Oreochromis mossambicus embryos were transferred from freshwater to seawater and vice versa, and short-term changes in the localization of three major ion transport proteins, Na+/K +-ATPase, Na+/K+/2Cl- cotransporter (NKCC) and cystic fibrosis transmembrane conductance regulator (CFTR) were examined within mitochondrion-rich cells (MRCs) in the embryonic yolk-sac membrane. Triple-color immunofluorescence staining allowed us to classify MRCs into four types: type I, showing only basolateral Na+/K +-ATPase staining; type II, basolateral Na+/K +-ATPase and apical NKCC; type III, basolateral Na+/K +-ATPase and basolateral NKCC; type IV, basolateral Na +/K+-ATPase, basolateral NKCC and apical CFTR. In freshwater, type-I, type-II and type-III cells were observed. Following transfer from freshwater to seawater, type-IV cells appeared at 12 h and showed a remarkable increase in number between 24 h and 48 h, whereas type-III cells disappeared. When transferred from seawater back to freshwater, type-IV cells decreased and disappeared at 48 h, type-III cells increased, and type-II cells, which were not found in seawater, appeared at 12 h and increased in number thereafter. Type-I cells existed consistently irrespective of salinity changes. These results suggest that type I is an immature MRC, type II is a freshwater-type ion absorptive cell, type III is a dormant type-IV cell and/or an ion absorptive cell (with a different mechanism from type II), and type IV is a seawater-type ion secretory cell. The intracellular localization of the three ion transport proteins in type-IV cells is completely consistent with a widely accepted model for ion secretion by MRCs. A new model for ion absorption is proposed based on type-II cells possessing apical NKCC.

Activation of ferret erythrocyte Na+–K+–2Cl− cotransport by deoxygenation

PubMed Central

Flatman, Peter W

2005-01-01

Deoxygenation of ferret erythrocytes stimulates Na+–K+–2Cl− cotransport by 111% (s.d., 46) compared to controls in air. Half-maximal activation occurs at a PO2 of 24 mmHg (s.d., 2) indicating that physiological changes in oxygen tension can influence cotransport function. Approximately 25–35% of this stimulation can be attributed to the rise of intracellular free magnesium concentration that occurs on deoxygenation (from 0.82 (s.d., 0.07) to 1.40 mm (s.d., 0.17)). Most of the stimulation is probably caused by activation of a kinase which can be prevented or reversed by treating cells with the kinase inhibitors PP1 or staurosporine, or by reducing cell magnesium content to submicromolar levels. Stimulation by deoxygenation is comparable with that caused by calyculin A or sodium arsenite, compounds that cause a 2- to 3-fold increase in threonine phosphorylation of the cotransporter which can be detected with phospho-specific antibodies. However, the same approach failed to detect significant changes in threonine phosphorylation following deoxygenation. The results suggest that deoxygenation causes activation of a kinase that either phosphorylates the transporter, but probably not on threonine, or phosphorylates another protein that in turn influences cotransporter behaviour. They also indicate that more than one kinase and phosphatase are involved in cotransporter phosphorylation. PMID:15618270

WNK-SPAK-NCC cascade revisited: WNK1 stimulates the activity of the Na-Cl cotransporter via SPAK, an effect antagonized by WNK4.

PubMed

Chávez-Canales, María; Zhang, Chong; Soukaseum, Christelle; Moreno, Erika; Pacheco-Alvarez, Diana; Vidal-Petiot, Emmanuelle; Castañeda-Bueno, María; Vázquez, Norma; Rojas-Vega, Lorena; Meermeier, Nicholas P; Rogers, Shaunessy; Jeunemaitre, Xavier; Yang, Chao-Ling; Ellison, David H; Gamba, Gerardo; Hadchouel, Juliette

2014-11-01

The with-no-lysine (K) kinases, WNK1 and WNK4, are key regulators of blood pressure. Their mutations lead to familial hyperkalemic hypertension (FHHt), associated with an activation of the Na-Cl cotransporter (NCC). Although it is clear that WNK4 mutants activate NCC via Ste20 proline-alanine-rich kinase, the mechanisms responsible for WNK1-related FHHt and alterations in NCC activity are not as clear. We tested whether WNK1 modulates NCC through WNK4, as predicted by some models, by crossing our recently developed WNK1-FHHt mice (WNK1(+/FHHt)) with WNK4(-/-) mice. Surprisingly, the activated NCC, hypertension, and hyperkalemia of WNK1(+/FHHt) mice remain in the absence of WNK4. We demonstrate that WNK1 powerfully stimulates NCC in a WNK4-independent and Ste20 proline-alanine-rich kinase-dependent manner. Moreover, WNK4 decreases the WNK1 and WNK3-mediated activation of NCC. Finally, the formation of oligomers of WNK kinases through their C-terminal coiled-coil domain is essential for their activity toward NCC. In conclusion, WNK kinases form a network in which WNK4 associates with WNK1 and WNK3 to regulate NCC. © 2014 American Heart Association, Inc.

Modeling glial contributions to seizures and epileptogenesis: cation-chloride cotransporters in Drosophila melanogaster.

PubMed

Rusan, Zeid M; Kingsford, Olivia A; Tanouye, Mark A

2014-01-01

Flies carrying a kcc loss-of-function mutation are more seizure-susceptible than wild-type flies. The kcc gene is the highly conserved Drosophila melanogaster ortholog of K+/Cl- cotransporter genes thought to be expressed in all animal cell types. Here, we examined the spatial and temporal requirements for kcc loss-of-function to modify seizure-susceptibility in flies. Targeted RNA interference (RNAi) of kcc in various sets of neurons was sufficient to induce severe seizure-sensitivity. Interestingly, kcc RNAi in glia was particularly effective in causing seizure-sensitivity. Knockdown of kcc in glia or neurons during development caused a reduction in seizure induction threshold, cell swelling, and brain volume increase in 24-48 hour old adult flies. Third instar larval peripheral nerves were enlarged when kcc RNAi was expressed in neurons or glia. Results suggest that a threshold of K+/Cl- cotransport dysfunction in the nervous system during development is an important determinant of seizure-susceptibility in Drosophila. The findings presented are the first attributing a causative role for glial cation-chloride cotransporters in seizures and epileptogenesis. The importance of elucidating glial cell contributions to seizure disorders and the utility of Drosophila models is discussed.

K-Cl cotransporters, cell volume homeostasis, and neurological disease.

PubMed

Kahle, Kristopher T; Khanna, Arjun R; Alper, Seth L; Adragna, Norma C; Lauf, Peter K; Sun, Dandan; Delpire, Eric

2015-08-01

K(+)-Cl(-) cotransporters (KCCs) were originally characterized as regulators of red blood cell (RBC) volume. Since then, four distinct KCCs have been cloned, and their importance for volume regulation has been demonstrated in other cell types. Genetic models of certain KCCs, such as KCC3, and their inhibitory WNK-STE20/SPS1-related proline/alanine-rich kinase (SPAK) serine-threonine kinases, have demonstrated the evolutionary necessity of these molecules for nervous system cell volume regulation, structure, and function, and their involvement in neurological disease. The recent characterization of a swelling-activated dephosphorylation mechanism that potently stimulates the KCCs has pinpointed a potentially druggable switch of KCC activity. An improved understanding of WNK/SPAK-mediated KCC cell volume regulation in the nervous system might reveal novel avenues for the treatment of multiple neurological diseases. Copyright © 2015 Elsevier Ltd. All rights reserved.

Na/beta-alumina/NaAlCl4, Cl2/C circulating cell

NASA Technical Reports Server (NTRS)

Cherng, Jing-Yih; Bennion, Douglas N.

1987-01-01

A study was made of a high specific energy battery based on a sodium negative electrode and a chlorine positive electrode with molten AlCl3-NaCl electrolyte and a solid beta alumina separator. The basic performance of a Na beta-alumina NaAlCl4, Cl2/C circulating cell at 200 C was demonstrated. This cell can be started at 150 C. The use of melting sodium chloroaluminate electrolyte overcomes some of the material problems associated with the high working temperatures of present molten salt systems, such as Na/S and LiAl/FeS, and retains the advantages of high energy density and relatively efficient electrode processes. Preliminary investigations were conducted on a sodium-chlorine static cell, material compability, electrode design, wetting, and theoretical calculations to assure a better chance of success before assembling a Na/Cl2 circulating cell. Mathematical models provide a theoretical explanation for the performance of the NaCl2 battery. The results of mathematical models match the experimental results very well. According to the result of the mathematical modeling, an output at 180 mA/sq cm and 3.2 V can be obtained with optimized cell design.

A thermochemical explanation for the stability of NaCl3 and NaCl7

NASA Astrophysics Data System (ADS)

Fernandes de Farias, Robson

2017-03-01

Thermodynamically stable cubic and orthorhombic NaCl3 as well as NaCl7 have been synthesized (Zhang et al., 2013). In the present work, a thermochemical explanation for the stability of such unusual sodium chlorides is provided, based on lattice energy values. Using the Glasser-Jenkins generalized equation (Glasser and Jenkins, 2000) lattice energies (kJ mol-1) of -162.5, -168.9 and -113.1 are calculated for Pm3n NaCl3, Pnma NaCl3 and NaCl7, respectively. It is postulated that any NaxCly compound could be synthesized, if the ionic character of the Nasbnd Cl bond in the prepared compound remains around 80%, and the sodium charge below unit.

Trehalose-producing enzymes MTSase and MTHase in Anabaena 7120 under NaCl stress.

PubMed

Asthana, Ravi K; Nigam, Subhasha; Maurya, Archana; Kayastha, Arvind M; Singh, Sureshwar P

2008-05-01

Salt tolerance, a multigenic trait, necessitates knowledge about biosynthesis and function of candidate gene(s) at the cellular level. Among the osmolytes, trehalose biosynthesis in cyanobacteria facing NaCl stress is little understood. Anabaena 7120 filaments exposed to 150 mM: NaCl fragmented and recovered on transfer to -NaCl medium with the increased heterocysts frequency (7%) over the control (4%). Cells failed to retain Na+ beyond a threshold [2.19 mM/cm3 (PCV)]. Whereas NaCl-stressed cells exhibited a marginal rise in K+ (1.1-fold) only at 30 h, for Na+ it was 130-fold at 48 h over cells in control. A time-course study (0-54 h) revealed reduction in intracellular Na+ beyond 48 h [0.80 mM/cm3 (PCV)] suggestive of ion efflux. The NaCl-stressed cells showed differential expression of maltooligosyltrehalose synthase (MTSase; EC 5.4.99.15) and maltooligosyltrehalose trehalohydrolase (MTHase; EC 3.2.1.141) depending on the time and the extent of intracellular Na+ buildup.

Acute Insulin Stimulation Induces Phosphorylation of the Na-Cl Cotransporter in Cultured Distal mpkDCT Cells and Mouse Kidney

PubMed Central

Sohara, Eisei; Rai, Tatemitsu; Yang, Sung-Sen; Ohta, Akihito; Naito, Shotaro; Chiga, Motoko; Nomura, Naohiro; Lin, Shih-Hua; Vandewalle, Alain; Ohta, Eriko; Sasaki, Sei; Uchida, Shinichi

2011-01-01

The NaCl cotransporter (NCC) is essential for sodium reabsorption at the distal convoluted tubules (DCT), and its phosphorylation increases its transport activity and apical membrane localization. Although insulin has been reported to increase sodium reabsorption in the kidney, the linkage between insulin and NCC phosphorylation has not yet been investigated. This study examined whether insulin regulates NCC phosphorylation. In cultured mpkDCT cells, insulin increased phosphorylation of STE20/SPS1-related proline-alanine-rich kinase (SPAK) and NCC in a dose-dependent manner. This insulin-induced phosphorylation of NCC was suppressed in WNK4 and SPAK knockdown cells. In addition, Ly294002, a PI3K inhibitor, decreased the insulin effect on SPAK and NCC phosphorylation, indicating that insulin induces phosphorylation of SPAK and NCC through PI3K and WNK4 in mpkDCT cells. Moreover, acute insulin administration to mice increased phosphorylation of oxidative stress-responsive kinase-1 (OSR1), SPAK and NCC in the kidney. Time-course experiments in mpkDCT cells and mice suggested that SPAK is upstream of NCC in this insulin-induced NCC phosphorylation mechanism, which was confirmed by the lack of insulin-induced NCC phosphorylation in SPAK knockout mice. Moreover, insulin administration to WNK4 hypomorphic mice did not increase phosphorylation of OSR1, SPAK and NCC in the kidney, suggesting that WNK4 is also involved in the insulin-induced OSR1, SPAK and NCC phosphorylation mechanism in vivo. The present results demonstrated that insulin is a potent regulator of NCC phosphorylation in the kidney, and that WNK4 and SPAK are involved in this mechanism of NCC phosphorylation by insulin. PMID:21909387

Gene expression of growth hormone family and glucocorticoid receptors, osmosensors, and ion transporters in the gill during seawater acclimation of Mozambique tilapia, Oreochromis mossambicus.

PubMed

Breves, Jason P; Fox, Bradley K; Pierce, Andrew L; Hirano, Tetsuya; Grau, E Gordon

2010-08-01

This study characterized endocrine and ionoregulatory responses accompanying seawater (SW) acclimation in Mozambique tilapia (Oreochromis mossambicus). Changes in plasma hormones and gene expression of hormone receptors, putative osmosensors, and ion transporters in the gill were measured. Transfer of freshwater (FW)-acclimated tilapia to SW resulted in a marked elevation in plasma osmolality and a significant rise in plasma growth hormone (GH) levels at 12 hr and 14 days after transfer. Significant reductions in plasma prolactin (PRL(177) and PRL(188)) levels also occurred in SW-transferred fish; no effect of transfer upon plasma cortisol or insulin-like growth factor I was observed. Gene expression of GH receptor increased strongly 6 hr after transfer, whereas PRL receptor was lower than controls at 12 hr. By contrast, mRNA levels of somatolactin and glucocorticoid receptors were unaffected by SW transfer. Osmotic stress transcription factor 1 mRNA levels rose significantly between 3 and 12 hr, whereas the calcium-sensing receptor was unaffected. Aquaporin-3 gene expression was strongly down-regulated during SW acclimation from 12 hr until the conclusion of the experiment. Na(+)/K(+)/2Cl(-) cotransporter gene expression increased significantly 3 hr after transfer, whereas expression of Na(+)/Cl(-) cotransporter, specific to FW-type chloride cells, declined by 6 hr into SW acclimation. The response of Na(+)/H(+) exchanger was less pronounced, but showed a similar pattern to that of the Na(+)/Cl(-) cotransporter. These results suggest that acquisition of hyposmoregulatory mechanisms in Mozambique tilapia entails the coordinated interaction of systemic hormones with local factors in the gill, including hormone receptors, ion transporters, and osmosensors. (c) 2010 Wiley-Liss, Inc.

Platelet-derived growth factor regulates K-Cl cotransport in vascular smooth muscle cells.

PubMed

Zhang, Jing; Lauf, Peter K; Adragna, Norma C

2003-03-01

Platelet-derived growth factor (PDGF), a potent serum mitogen for vascular smooth muscle cells (VSMCs), plays an important role in membrane transport regulation and in atherosclerosis. K-Cl cotransport (K-Cl COT/KCC), the coupled-movement of K and Cl, is involved in ion homeostasis. VSMCs possess K-Cl COT activity and the KCC1 and KCC3 isoforms. Here, we report on the effect of PDGF on K-Cl COT activity and mRNA expression in primary cultures of rat VSMCs. K-Cl COT was determined as the Cl-dependent Rb influx and mRNA expression by semiquantitative RT-PCR. Twenty four-hour serum deprivation inhibited basal K-Cl COT activity. Addition of PDGF increased total protein content and K-Cl COT activity in a time-dependent manner. PDGF activated K-Cl COT in a dose-dependent manner, both acutely (10 min) and chronically (12 h). AG-1296, a selective inhibitor of the PDGF receptor tyrosine kinase, abolished these effects. Actinomycin D and cycloheximide had no effect on the acute PDGF activation of K-Cl COT, suggesting posttranslational regulation by the drug. Furthermore, PDGF increased KCC1 and decreased KCC3 mRNA expression in a time-dependent manner. These results indicate that chronic activation of K-Cl COT activity by PDGF may involve regulation of the two KCC mRNA isoforms, with KCC1 playing a dominant role in the mechanism of PDGF-mediated activation.

Acclimation of brackish water pearl spot (Etroplus suratensis) to various salinities: relative changes in abundance of branchial Na(+)/K (+)-ATPase and Na (+)/K (+)/2Cl (-) co-transporter in relation to osmoregulatory parameters.

PubMed

Chandrasekar, S; Nich, T; Tripathi, G; Sahu, N P; Pal, A K; Dasgupta, S

2014-06-01

The present study was conducted to elucidate the osmoregulatory ability of the fish pearl spot (Etroplus suratensis) to know the scope of this species for aquaculture under various salinities. Juvenile pearl spot were divided into three groups and acclimated to freshwater (FW), brackish water (BW) or seawater (SW) for 15 days. The fish exhibited effective salinity tolerance under osmotic challenges. Although the plasma osmolality and Na(+), K(+) and Cl(-) levels increased with the increasing salinities, the parameters remained within the physiological range. The muscle water contents were constant among FW-, BW- and SW-acclimated fish. Two Na+/K+-ATPase α-isoforms (NKA α) were expressed in gills during acclimation in FW, BW and SW. Abundance of one isoform was up-regulated in response to seawater acclimation, suggesting its role in ion secretion similar to NKA α1b, while expression of another isoform was simultaneously up-regulated in response to both FW and SW acclimation, suggesting the presence of isoforms switching phenomenon during acclimation to different salinities. Nevertheless, NKA enzyme activities in the gills of the SW and FW individuals were higher (p < 0.05) than in BW counterparts. Immunohistochemistry revealed that Na(+)/K(+)-ATPase immunoreactive (NKA-IR) cells were mainly distributed in the interlamellar region of the gill filaments in FW groups and in the apical portion of the filaments in BW and SW groups. The number of NKA-IR cells in the gills of the FW-acclimated fish was almost similar to that of SW individuals, which exceeded that of the BW individuals. The NKA-IR cells of BW and SW were bigger in size than their FW counterparts. Besides, the relative abundance of branchial Na(+)/K(+)/2Cl(-) co-transporter showed stronger evidence in favor of involvement of this protein in hypo-osmoregulation, requiring ion secretion by the chloride cells. To the best of our knowledge, this is the first study reporting the wide salinity tolerance of E

Water transport by Na+-coupled cotransporters of glucose (SGLT1) and of iodide (NIS). The dependence of substrate size studied at high resolution

PubMed Central

Zeuthen*, Thomas; Belhage, Bo; Zeuthen, Emil

2006-01-01

The relation between substrate and water transport was studied in Na+-coupled cotransporters of glucose (SGLT1) and of iodide (NIS) expressed in Xenopus oocytes. The water transport was monitored from changes in oocyte volume at a resolution of 20 pl, more than one order of magnitude better than previous investigations. The rate of cotransport was monitored as the clamp current obtained from two-electrode voltage clamp. The high resolution data demonstrated a fixed ratio between the turn-over of the cotransporter and the rate of water transport. This applied to experiments in which the rate of cotransport was changed by isosmotic application of substrate, by rapid changes in clamp voltage, or by poisoning. Transport of larger substrates gave rise to less water transport. For the rabbit SGLT1, 378 ± 20 (n = 18 oocytes) water molecules were cotransported along with the 2 Na+ ions and the glucose-analogue α-MDG (MW 194); using the larger sugar arbutin (MW 272) this number was reduced by a factor of at least 0.86 ± 0.03 (15). For the human SGLT1 the respective numbers were 234 ± 12 (18) and 0.85 ± 0.8 (7). For NIS, 253 ± 16 (12) water molecules were cotransported for each 2 Na+ and 1 thiocyanate (SCN−, MW 58), with I− as anion (MW 127) only 162 ± 11 (19) water molecules were cotransported. The effect of substrate size suggests a molecular mechanism for water cotransport and is opposite to what would be expected from unstirred layer effects. Data were analysed by a model which combined cotransport and osmosis at the membrane with diffusion in the cytoplasm. The combination of high resolution measurements and precise modelling showed that water transport across the membrane can be explained by cotransport of water in the membrane proteins and that intracellular unstirred layers effects are minute. PMID:16322051

Bicarbonate-dependent and -independent intracellular pH regulatory mechanisms in rat hepatocytes. Evidence for Na+-HCO3- cotransport.

PubMed Central

Gleeson, D; Smith, N D; Boyer, J L

1989-01-01

Using the pH-sensitive dye 2,7-bis(carboxyethyl)-5(6)-carboxy-fluorescein and a continuously perfused subconfluent hepatocyte monolayer cell culture system, we studied rat hepatocyte intracellular pH (pHi) regulation in the presence (+HCO3-) and absence (-HCO3-) of bicarbonate. Baseline pHi was higher (7.28 +/- 09) in +HCO3- than in -HCO3- (7.16 +/- 0.14). Blocking Na+/H+ exchange with amiloride had no effect on pHi in +HCO3- but caused reversible 0.1-0.2-U acidification in -HCO3- or in +HCO3- after preincubation in the anion transport inhibitor 4,4'-diisothiocyano-2,2'-disulfonic acid stilbene (DIDS). Acute Na+ replacement in +HCO3- alos caused acidification which was amiloride independent but DIDS inhibitible. The recovery of pHi from an intracellular acid load (maximum H+ efflux rate) was 50% higher in +HCO3- than in -HCO3-. Amiloride inhibited H+ effluxmax by 75% in -HCO3- but by only 27% in +HCO3-. The amiloride-independent pHi recovery in +HCO3- was inhibited 50-63% by DIDS and 79% by Na+ replacement but was unaffected by depletion of intracellular Cl-, suggesting that Cl-/HCO3- exchange is not involved. Depolarization of hepatocytes (raising external K+ from 5 to 25 mM) caused reversible 0.05-0.1-U alkalinization, which, however, was neither Na+ nor HCO3- dependent, nor DIDS inhibitible, findings consistent with electroneutral HCO3- transport. We conclude that Na+-HCO3- cotransport, in addition to Na+/H+ exchange, is an important regulator of pHi in rat hepatocytes. PMID:2544626

Regulation of the Na+2Cl–K+ cotransporter in in vitro perfused rectal gland tubules of Squalus acanthias.

PubMed

Warth, R; Bleich, M; Thiele, I; Lang, F; Greger, R

1998-07-01

Previously it has been shown that the Na+2Cl–K+ cotransporter accepts NH4 + at its K+ binding site. This property can be used to estimate its transport rates by adding NH4 + to the bath and measuring the initial furosemide-dependent rates of change in BCECF fluorescence. We have utilized this technique to determine the regulation of the furosemide-inhibitable Na+2Cl–K+ cotransporter in in vitroperfused rectal gland tubules (RGT) of Squalus acanthias. Addition of NH4 + to the bath (20 mmol/l) led to an initial alkalinization, corresponding to NH3 uptake. This was followed by an acidification, corresponding to NH4 + uptake. The rate of this uptake was quantified by exponential curve fitting and is given in arbitrary units (Δfluorescence/time). This acidification could be completely inhibited by furosemide. In the absence of any secretagogue preincubation of RGT in a low Cl– solution (6 mmol/l, low Cl–) for 10 min enhanced the uptake rate significantly from 4.04±0.51 to 12.7±1.30 (n=5). The addition of urea (200 mmol/l) was without effect, but the addition of 300 mmol/l mannitol (+300 mannitol) enhanced the rate significantly from 7.24±1.33 to 14.7±4.6 (n=6). Stimulation of NaCl secretion by a solution maximizing the cytosolic cAMP concentration (Stim) led to a significant increase in NH4 + uptake rate from 5.00±1.33 to 13.3±1.54 (n=6). Similar results were obtained in the additional presence of Ba2+ (1 mmol/l): the uptake rate was increased significantly from 4.23±0.34 to 15.1±1.86 (n=16). In the presence of Stim low Cl– had no additional effect on the uptake rate: 15.1±3.1 versus 15.2±2.8 in high Cl– (n=6). The uptake rate in Stim containing additional +300 mannitol (22.3±4.0, n=5) was not significantly different from that obtained with Stim or +300 mannitol alone. By whatever mechanism the NH4 + uptake rate was increased furosemide (500 µmol/l) always reduced this rate to control values. Hence three manoeuvres enhanced furosemide

Proteome Analyses of Staphylococcus aureus Biofilm at Elevated Levels of NaCl

PubMed Central

Islam, Nazrul; Ross, Julia M; Marten, Mark R

2016-01-01

Our studies demonstrate that sodium chloride (NaCl) induces changes in biofilm, mediated by increased production of polysaccharides intercellular adhesion (PIA). We identified 12 proteins that showed higher abundance in increased level of NaCl. This includes one important protein (IsaA) known to be associated with biofilm stability. In addition, we also found higher abundance of a cold shock protein, CspA, at higher NaCl. We have also identified several other proteins that are differentially expressed to the elevated levels of NaCl and mapped them in the regulatory pathways of PIA. The majority of proteins are involved with various aspects bacterial metabolic function. Our results demonstrated that NaCl influences gene regulatory networks controlling exopolysaccharide expression. PMID:26973848

Expression of three isoforms of Na-K-2Cl cotransporter (NKCC2) in the kidney and regulation by dehydration.

PubMed

Itoh, Kazuko; Izumi, Yuichiro; Inoue, Takeaki; Inoue, Hideki; Nakayama, Yushi; Uematsu, Takayuki; Fukuyama, Takashi; Yamazaki, Taiga; Yasuoka, Yukiko; Makino, Takeshi; Nagaba, Yasushi; Tomita, Kimio; Kobayashi, Noritada; Kawahara, Katsumasa; Mukoyama, Masashi; Nonoguchi, Hiroshi

2014-10-24

Sodium reabsorption via Na-K-2Cl cotransporter 2 (NKCC2) in the thick ascending limbs has a major role for medullary osmotic gradient and subsequent water reabsorption in the collecting ducts. We investigated intrarenal localization of three isoforms of NKCC2 mRNA expressions and the effects of dehydration on them in rats. To further examine the mechanisms of dehydration, the effects of hyperosmolality on NKCC2 mRNA expression in microdissected renal tubules was studied. RT-PCR and RT-competitive PCR were employed. The expressions of NKCC2a and b mRNA were observed in the cortical thick ascending limbs (CAL) and the distal convoluted tubules (DCT) but not in the medullary thick ascending limbs (MAL), whereas NKCC2f mRNA expression was seen in MAL and CAL. Two-day dehydration did not affect these mRNA expressions. In contrast, hyperosmolality increased NKCC2 mRNA expression in MAL in vitro. Bradykinin dose-dependently decreased NKCC2 mRNA expression in MAL. However, dehydration did not change NKCC2 protein expression in membrane fraction from cortex and outer medulla and in microdissected MAL. These data show that NKCC2a/b and f types are mainly present in CAL and MAL, respectively. Although NKCC2 mRNA expression was stimulated by hyperosmolality in vitro, NKCC2 mRNA and protein expressions were not stimulated by dehydration in vivo. These data suggest the presence of the inhibitory factors for NKCC2 expression in dehydration. Considering the role of NKCC2 for the countercurrent multiplier system, NKCC2f expressed in MAL might be more important than NKCC2a/b. Copyright © 2014 Elsevier Inc. All rights reserved.

Novel insights regarding the operational characteristics and teleological purpose of the renal Na+-K+-Cl2 cotransporter (NKCC2s) splice variants.

PubMed

Brunet, Geneviève M; Gagnon, Edith; Simard, Charles F; Daigle, Nikolas D; Caron, Luc; Noël, Micheline; Lefoll, Marie-Hélène; Bergeron, Marc J; Isenring, Paul

2005-10-01

The absorptive Na(+)-K(+)-Cl(-) cotransporter (NKCC2) is a polytopic protein that forms homooligomeric complexes in the apical membrane of the thick ascending loop of Henle (TAL). It occurs in at least four splice variants (called B, A, F, and AF) that are identical to one another except for a short region in the membrane-associated domain. Although each of these variants exhibits unique functional properties and distributions along the TAL, their teleological purpose and structural organization remain poorly defined. In the current work, we provide additional insight in these regards by showing in mouse that the administration of either furosemide or an H(2)O-rich diet, which are predicted to alter NKCC2 expression in the TAL, exerts differential effects on mRNA levels for the variants, increasing those of A (furosemide) but decreasing those of F and AF (furosemide or H(2)O). Based on a yeast two-hybrid mapping analysis, we also show that the formation of homooligomeric complexes is mediated by two self-interacting domains in the COOH terminus (residues 671 to 816 and 910 to 1098), and that these complexes could probably include more than one type of variant. Taken together, the data reported here suggest that A, F, and AF each play unique roles that are adapted to specific physiological needs, and that the accomplishment of such roles is coordinated through the splicing machinery as well as complex NKCC2-NKCC2 interactions.

Temperature-dependent formation of NaCl dihydrate in levitated NaCl and sea salt aerosol particles.

PubMed

Peckhaus, Andreas; Kiselev, Alexei; Wagner, Robert; Duft, Denis; Leisner, Thomas

2016-12-28

Recent laboratory studies indicate that the hydrated form of crystalline NaCl is potentially important for atmospheric processes involving depositional ice nucleation on NaCl dihydrate particles under cirrus cloud conditions. However, recent experimental studies reported a strong discrepancy between the temperature intervals where the efflorescence of NaCl dihydrate has been observed. Here we report the measurements of the volume specific nucleation rate of crystalline NaCl in the aqueous solution droplets of pure NaCl suspended in an electrodynamic balance at constant temperature and humidity in the range from 250 K to 241 K. Based on these measurements, we derive the interfacial energy of crystalline NaCl dihydrate in a supersaturated NaCl solution and determined its temperature dependence. Taking into account both temperature and concentration dependence of nucleation rate coefficients, we explain the difference in the observed fractions of NaCl dihydrate reported in the previous studies. Applying the heterogeneous classical nucleation theory model, we have been able to reproduce the 5 K shift of the NaCl dihydrate efflorescence curve observed for the sea salt aerosol particles, assuming the presence of super-micron solid inclusions (hypothetically gypsum or hemihydrate of CaSO 4 ). These results support the notion that the phase transitions in microscopic droplets of supersaturated solution should be interpreted by accounting for the stochastic nature of homogeneous and heterogeneous nucleation and cannot be understood on the ground of bulk phase diagrams alone.

Temperature-dependent formation of NaCl dihydrate in levitated NaCl and sea salt aerosol particles

NASA Astrophysics Data System (ADS)

Peckhaus, Andreas; Kiselev, Alexei; Wagner, Robert; Duft, Denis; Leisner, Thomas

2016-12-01

Recent laboratory studies indicate that the hydrated form of crystalline NaCl is potentially important for atmospheric processes involving depositional ice nucleation on NaCl dihydrate particles under cirrus cloud conditions. However, recent experimental studies reported a strong discrepancy between the temperature intervals where the efflorescence of NaCl dihydrate has been observed. Here we report the measurements of the volume specific nucleation rate of crystalline NaCl in the aqueous solution droplets of pure NaCl suspended in an electrodynamic balance at constant temperature and humidity in the range from 250 K to 241 K. Based on these measurements, we derive the interfacial energy of crystalline NaCl dihydrate in a supersaturated NaCl solution and determined its temperature dependence. Taking into account both temperature and concentration dependence of nucleation rate coefficients, we explain the difference in the observed fractions of NaCl dihydrate reported in the previous studies. Applying the heterogeneous classical nucleation theory model, we have been able to reproduce the 5 K shift of the NaCl dihydrate efflorescence curve observed for the sea salt aerosol particles, assuming the presence of super-micron solid inclusions (hypothetically gypsum or hemihydrate of CaSO4). These results support the notion that the phase transitions in microscopic droplets of supersaturated solution should be interpreted by accounting for the stochastic nature of homogeneous and heterogeneous nucleation and cannot be understood on the ground of bulk phase diagrams alone.

Measurements of the liquidus surface and solidus transitions of the NaCl-UCl3 and NaCl-UCl3-CeCl3 phase diagrams

NASA Astrophysics Data System (ADS)

Sooby, E. S.; Nelson, A. T.; White, J. T.; McIntyre, P. M.

2015-11-01

NaCl-UCl3-PuCl3 is proposed as the fuel salt for a number of molten salt reactor concepts. No experimental data exists for the ternary system, and limited data is available for the binary compositions of this salt system. Differential scanning calorimetry is used in this study to examine the liquidus surface and solidus transition of a surrogate fuel-salt (NaCl-UCl3-CeCl3) and to reinvestigate the NaCl-UCl3 eutectic phase diagram. The results of this study show good agreement with previously reported data for the pure salt compounds used (NaCl, UCl3, and CeCl3) as well as for the eutectic points for the NaCl-UCl3 and NaCl-CeCl3 binary systems. The NaCl-UCl3 liquidus surface produced in this study predicts a 30-40 °C increase on the NaCl-rich side of the binary phase diagram. The increase in liquidus temperature could prove significant to molten salt reactor modeling.

Role of endolymphatic anion transport in forskolin-induced Cl- activity increase of scala media.

PubMed

Kitano, I; Mori, N; Matsunaga, T

1995-03-01

To determine the role of anion transport in the forskolin-induced Cl- increase of scala media (SM), effects of forskolin on the EP (endocochlear potential) and Cl- activity (ACl) in SM were examined with double-barrelled Cl(-)-selective microelectrodes. The experiments were carried out on guinea pig cochleae, using a few anion transport inhibitors: IAA-94 for a Cl- channel blocker, bumetanide (BU) for an Na+/K+/2Cl- cotransport blocker, and SITS and DIDS for Cl-/HCO3- exchange blockers. The application of forskolin (200 microM) into scala vestibuli (SV) caused a 20 mEq increase of endolymphatic ACl and a 15 mV elevation of EP, and IAA-94 with forskolin completely abolished these responses. Although each application of BU, SITS or DIDS did not completely suppress EP elevation, the concurrent application of these inhibitors completely suppressed EP with endolymphatic ACl increase. The results indicate the involvement of Cl- channels, Na+/K+/2Cl- cotransport and Cl-/HCO3- exchange in forskolin-induced increase of ACl and EP. The role of adenylate cyclase activation and Cl- transport in endolymph homeostasis was discussed.

A role for the circadian clock protein Per1 in the regulation of the NaCl co-transporter (NCC) and the with-no-lysine kinase (WNK) cascade in mouse distal convoluted tubule cells.

PubMed

Richards, Jacob; Ko, Benjamin; All, Sean; Cheng, Kit-Yan; Hoover, Robert S; Gumz, Michelle L

2014-04-25

It has been well established that blood pressure and renal function undergo circadian fluctuations. We have demonstrated that the circadian protein Per1 regulates multiple genes involved in sodium transport in the collecting duct of the kidney. However, the role of Per1 in other parts of the nephron has not been investigated. The distal convoluted tubule (DCT) plays a critical role in renal sodium reabsorption. Sodium is reabsorbed in this segment through the actions of the NaCl co-transporter (NCC), which is regulated by the with-no-lysine kinases (WNKs). The goal of this study was to test if Per1 regulates sodium transport in the DCT through modulation of NCC and the WNK kinases, WNK1 and WNK4. Pharmacological blockade of nuclear Per1 entry resulted in decreased mRNA expression of NCC and WNK1 but increased expression of WNK4 in the renal cortex of mice. These findings were confirmed by using Per1 siRNA and pharmacological blockade of Per1 nuclear entry in mDCT15 cells, a model of the mouse distal convoluted tubule. Transcriptional regulation was demonstrated by changes in short lived heterogeneous nuclear RNA. Chromatin immunoprecipitation experiments demonstrated interaction of Per1 and CLOCK with the promoters of NCC, WNK1, and WNK4. This interaction was modulated by blockade of Per1 nuclear entry. Importantly, NCC protein expression and NCC activity, as measured by thiazide-sensitive, chloride-dependent (22)Na uptake, were decreased upon pharmacological inhibition of Per1 nuclear entry. Taken together, these data demonstrate a role for Per1 in the transcriptional regulation of NCC, WNK1, and WNK4.

Regulation of the Na(+)-K(+)-2Cl(-) cotransporter by cGMP/cGMP-dependent protein kinase I after furosemide administration.

PubMed

Limmer, Franziska; Schinner, Elisabeth; Castrop, Hayo; Vitzthum, Helga; Hofmann, Franz; Schlossmann, Jens

2015-10-01

Sodium chloride reabsorption in the thick ascending limb of the loop of Henle is mediated by the Na(+)-K(+)-2Cl(-) cotransporter (NKCC2). The loop diuretic furosemide is a potent inhibitor of NKCC2. However, less is known about the mechanism regulating the electrolyte transporter. Considering the well-established effects of nitric oxide on NKCC2 activity, cGMP is likely involved in this regulation. cGMP-dependent protein kinase I (cGKI; PKGI) is a cGMP target protein that phosphorylates different substrates after activation through cGMP. We investigated the potential correlation between the cGMP/cGKI pathway and NKCC2 regulation. We treated wild-type (wt) and cGKIα-rescue mice with furosemide. cGKIα-rescue mice expressed cGKIα only under the control of the smooth muscle-specific transgelin (SM22) promoter in a cGKI deficient background. Furosemide treatment increased the urine excretion of sodium and chloride in cGKIα-rescue mice compared to that in wt mice. We analyzed the phosphorylation of NKCC2 by western blotting and immunostaining using the phosphospecific antibody R5. The administration of furosemide significantly increased the phosphorylated NKCC2 signal in wt but not in cGKIα-rescue mice. NKCC2 activation led to its phosphorylation and membrane translocation. To examine whether cGKI was involved in this process, we analyzed vasodilator-stimulated phosphoprotein, which is phosphorylated by cGKI. Furosemide injection resulted in increased vasodilator-stimulated phosphoprotein phosphorylation in wt mice. We hypothesize that furosemide administration activated cGKI, leading to NKCC2 phosphorylation and membrane translocation. This cGKI-mediated pathway could be a mechanism to compensate for the inhibitory effect of furosemide on NKCC2. © 2015 FEBS.

A sea urchin Na(+)K(+)2Cl(-) cotransporter is involved in the maintenance of calcification-relevant cytoplasmic cords in Strongylocentrotus droebachiensis larvae.

PubMed

Basse, Wiebke C; Gutowska, Magdalena A; Findeisen, Ulrike; Stumpp, Meike; Dupont, Sam; Jackson, Daniel J; Himmerkus, Nina; Melzner, Frank; Bleich, Markus

2015-09-01

The cellular mechanisms of calcification in sea urchin larvae are still not well understood. Primary mesenchyme cells within the larval body cavity form a syncytium to secrete CaCO3 spicules from intracellular amorphous CaCO3 (ACC) stores. We studied the role of Na(+)K(+)2Cl(-) cotransporter (NKCC) in intracellular ACC accumulation and larval spicule formation of Strongylocentrotus droebachiensis. First, we incubated growing larvae with three different loop diuretics (azosemide, bumetanide, and furosemide) and established concentration-response curves. All loop diuretics were able to inhibit calcification already at concentrations that specifically inhibit NKCC. Calcification was most effectively inhibited by azosemide (IC50=6.5 μM), while larval mortality and swimming ability were not negatively impacted by the treatment. The inhibition by bumetanide (IC50=26.4 μM) and furosemide (IC50=315.4 μM) resembled the pharmacological fingerprint of the mammalian NKCC1 isoform. We further examined the effect of azosemide on the maintenance of cytoplasmic cords and on the occurrence of calcification vesicles using fluorescent dyes (calcein, FM1-43). Fifty micromolars of azosemide inhibited the maintenance of cytoplasmic cords and resulted in increased calcein fluorescence within calcification vesicles. The expression of NKCC in S. droebachiensis was verified by PCR and Western blot with a specific NKCC antibody. In summary, the pharmacological profile of loop diuretics and their specific effects on calcification in sea urchin larvae suggest that they act by inhibition of NKCC via repression of cytoplasmic cord formation and maintenance. Copyright © 2015 Elsevier Inc. All rights reserved.

Superconductivity could occur Na-supersaturated NaCl

NASA Astrophysics Data System (ADS)

Hanaki, Koji

1997-04-01

A flow-into electron and a flow-out hole mean flow-into of two unit electric c harges. Even if an exciton consisting of an electron and a hole is a neutral q uasi-particle, overlapping of excitons, namely, the bose condensation changes into a superconductor where half the electric current is due to holes moving t oward the reverse direction. The Meisner effect of the bose condensation comes from the precession of the each exciton under the magnetic field^1. Moreo ver, the present mechanism is supported with that superconducting material alw ays has two kinds of carriers. The superconductivity of NaCl comes from the ab ove-mentioned theory. Free stable holes at first and then electrons are produc ed in NaCl when considerable number of Cl^- lattice vacancies are brought in NaCl mainly because some electrons in the Cl-3p filled band fall into the v acancies. The coexistence of two kinds of stable carriers does not always mean the presence of excitons like VO with electrons not paired and localized in e ach V atom though. While, the absorption spectrum of the NaCl has already conf irmed the presence of excitons; the strength of the spectrum seems to indicate the formation of the bose condensation. Thus we could expect a new supercondu ctor. 1) Hanaki B.Am.P.Soc.,40-1(1995)568

Mutations in the Na+/Citrate Cotransporter NaCT (SLC13A5) in Pediatric Patients with Epilepsy and Developmental Delay

PubMed Central

Klotz, Jenna; Porter, Brenda E; Colas, Claire; Schlessinger, Avner; Pajor, Ana M

2016-01-01

Mutations in the SLC13A5 gene that codes for the Na+/citrate cotransporter, NaCT, are associated with early onset epilepsy, developmental delay and tooth dysplasia in children. In this study, we identify additional SLC13A5 mutations in nine epilepsy patients from six families. To better characterize the syndrome, families with affected children answered questions about the scope of illness and the treatment strategies. Currently, there are no effective treatments, but some antiepileptic drugs targeting the γ-aminobutyric acid system reduce seizure frequency. Acetazolamide, a carbonic anhydrase inhibitor and atypical antiseizure medication, decreases seizures in four patients. In contrast to previous reports, the ketogenic diet and fasting resulted in worsening of symptoms. The effects of the mutations on NaCT transport function and protein expression were examined by transient transfections of COS-7 cells. There was no transport activity from any of the mutant transporters, although some of the mutant transporter proteins were present on the plasma membrane. The structural model of NaCT suggests that these mutations can affect helix packing or substrate binding. We tested various treatments, including chemical chaperones and low temperatures, but none improved transport function in the NaCT mutants. Interestingly, coexpression of NaCT and the mutants results in decreased protein expression and activity of the wild-type transporter, indicating functional interaction. In conclusion, this study has identified additional SLC13A5 mutations in patients with chronic epilepsy starting in the neonatal period, with the mutations producing inactive Na+/citrate transporters. PMID:27261973

Impaired natriuretic response to high-NaCl diet plus aldosterone infusion in mice overexpressing human CD39, an ectonucleotidase (NTPDase1).

PubMed

Zhang, Yue; Robson, Simon C; Morris, Kaiya L; Heiney, Kristina M; Dwyer, Karen M; Kishore, Bellamkonda K; Ecelbarger, Carolyn M

2015-06-15

Extracellular nucleotides acting through P2 receptors facilitate natriuresis. To define how purinergic mechanisms are involved in sodium homeostasis, we used transgenic (TG) mice that globally overexpress human CD39 (hCD39, NTPDase1), an ectonucleotidase that hydrolyzes extracellular ATP/ADP to AMP, resulting in an altered extracellular purine profile. On a high-sodium diet (HSD, 3.5% Na(+)), urine volume and serum sodium were significantly higher in TG mice but sodium excretion was unaltered. Furthermore, TG mice showed an attenuated fall in urine aldosterone with HSD. Western blot analysis revealed significantly lower densities (∼40%) of the β-subunit of the epithelial sodium channel (ENaC) in medulla, and the major band (85-kDa) of γ-ENaC in TG mice cortex. To evaluate aldosterone-independent differences, in a second experiment, aldosterone was clamped by osmotic minipump at 20 μg/day, and mice were fed either an HSD or a low-sodium diet (LSD, 0.03% Na(+)). Here, no differences in urine volume or osmolality, or serum aldosterone were found, but TG mice showed a modest, yet significant impairment in late natriuresis (days 3 and 4). Several major sodium transporters or channel subunits were differentially expressed between the genotypes. HSD caused a downregulation of Na-Cl cotransporter (NCC) in both genotypes; and had higher cortical levels of NCC, Na-K-ATPase (α-1 subunit), and α- and γ-ENaC. The Na-K-2Cl cotransporter (NKCC2) was downregulated by HSD in wild-type mice, but it increased in TG mice. In summary, our data support the concept that extracellular nucleotides facilitate natriuresis; they also reveal an aldosterone-independent downregulation of major renal sodium transporters and channel subunits by purinergic signaling.

Evidence for the role of a Na(+)/HCO(3)(-) cotransporter in trout hepatocyte pHi regulation.

PubMed

Furimsky, M; Moon, T W; Perry, S F

2000-07-01

The mechanisms of intracellular pH (pHi) regulation were examined in hepatocytes of the rainbow trout Oncorhynchus mykiss. pHi was monitored using the pH-sensitive fluorescent dye BCECF, and the effects of various media and pharmacological agents were examined for their influence on baseline pHi and recovery rates from acid and base loading. Rates of Na(+) uptake were measured using (22)Na, and changes in membrane potential were examined using the potentiometric fluorescent dye Oxonol VI. The rate of proton extrusion following acid loading was diminished by the blockade of either Na(+)/H(+) exchange (using amiloride) or anion transport (using DIDS). The removal of external HCO(3)(-) and the abolition of outward K(+) diffusion by the channel blocker Ba(2+) also decreased the rate of proton extrusion following acid load. Depolarization of the cell membrane with 50 mmol l(-)(1) K(+), however, did not affect pHi. The rate of recovery from base loading was significantly diminished by the blockade of anion transport, removal of external HCO(3)(-) and, to a lesser extent, by blocking Na(+)/H(+) exchange. The blockade of K(+) conductance had no effect. The decrease in Na(+) uptake rate observed in the presence of the anion transport blocker DIDS and the DIDS-sensitive hyperpolarization of membrane potential during recovery from acid loading suggest that a Na(+)-dependent electrogenic transport system is involved in the restoration of pHi after intracellular acidification. The effects on baseline pHi indicate that the different membrane exchangers are tonically active in the maintenance of steady-state pHi. This study confirms the roles of a Na(+)/H(+) exchanger and a Cl(-)/HCO(3)(-) exchanger in the regulation of trout hepatocyte pHi and provides new evidence that a Na(+)/HCO(3)(-) cotransporter contributes to pHi regulation.

NaCl stress impact on the key enzymes in glycolysis from Lactobacillus bulgaricus during freeze-drying.

PubMed

Li, Chun; Sun, Jinwei; Qi, Xiaoxi; Liu, Libo

2015-01-01

The viability of Lactobacillus bulgaricus in freeze-drying is of significant commercial interest to dairy industries. In the study, L.bulgaricus demonstrated a significantly improved (p < 0.05) survival rate during freeze-drying when subjected to a pre-stressed period under the conditions of 2% (w/v) NaCl for 2 h in the late growth phase. The main energy source for the life activity of lactic acid bacteria is related to the glycolytic pathway. To investigate the phenomenon of this stress-related viability improvement in L. bulgaricus, the activities and corresponding genes of key enzymes in glycolysis during 2% NaCl stress were studied. NaCl stress significantly enhanced (p < 0.05) glucose utilization. The activities of glycolytic enzymes (phosphofructokinase, pyruvate kinase, and lactate dehydrogenase) decreased during freeze-drying, and NaCl stress were found to improve activities of these enzymes before and after freeze-drying. However, a transcriptional analysis of the corresponding genes suggested that the effect of NaCl stress on the expression of the pfk2 gene was not obvious. The increased survival of freeze-dried cells of L. bulgaricus under NaCl stress might be due to changes in only the activity or translation level of these enzymes in different environmental conditions but have no relation to their mRNA transcription level.

Heterogeneous Reaction of ClONO2(g) + NaCl(s) to Cl2(g) + NaNO3(s)

NASA Technical Reports Server (NTRS)

Timonen, Raimo S.; Chu, Liang T.; Leu, Ming-Taun; Keyser, Leon F.

1994-01-01

The heterogeneous reaction of ClON02 + NaCl yields Cl2 + NaNO3 (eq 1) was investigated over a temperature range 220-300 K in a flow-tube reactor interfaced with a differentially pumped quadrupole mass spectrometer. Partial pressures of ClON02 in the range 10(exp -8) - 10(exp -5) Torr were used. Granule sizes and surface roughness of the NaCl substrates were determined by using a scanning electron microscope, and in separate experiments, surface areas of the substrates were measured by using BET analysis of gas-adsorption isotherms. For dry NaCl substrates, both the decay rates of ClON02 and the growth rates Of C12 were used to obtain reaction probabilities, gamma(sub l) = (4.6 +/- 3.0) x 10(exp -3) at 296 K and (6.7 +/- 3.2) x 10(exp -1) at 225 K, after considering the internal surface area, The error bars represent 1 standard deviation. The Cl2 yield based on the ClONO2 reacted was measured to be 1.0 +/- 0.2. In order to mimic the conditions encountered in the lower stratosphere, the effect of water vapor pressures between 5 x 10(exp -5) and 3 x 10(exp -4) Torr on reaction 1 was also studied. With added H20, reaction probabilities, gamma = (4.1 +/- 2.1) x 10(exp -3) at 296 K and (4.7 +/- 2.9) x 10(exp -3) at 225 K, were obtained. A trace of HOCl, the reaction product from the ClON02 + H20 yield HOCl + HN03 reaction, was observed in addition to the C12 product from reaction 1. The implications of this result for the enhancement of hydrogen chloride in the stratosphere after the El Chichon volcanic eruption and for the marine troposphere are discussed.

Recovery of Na-glucose cotransport activity after renal ischemia is impaired in mice lacking vimentin.

PubMed

Runembert, Isabelle; Couette, Sylviane; Federici, Pierre; Colucci-Guyon, Emma; Babinet, Charles; Briand, Pascale; Friedlander, Gérard; Terzi, Fabiola

2004-11-01

Vimentin, an intermediate filament protein mainly expressed in mesenchyma-derived cells, is reexpressed in renal tubular epithelial cells under many pathological conditions, characterized by intense cell proliferation. Whether vimentin reexpression is only a marker of cell dedifferentiation or is instrumental in the maintenance of cell structure and/or function is still unknown. Here, we used vimentin knockout mice (Vim(-/-)) and an experimental model of acute renal injury (30-min bilateral renal ischemia) to explore the role of vimentin. Bilateral renal ischemia induced an initial phase of acute tubular necrosis that did not require vimentin and was similar, in terms of morphological and functional changes, in Vim(+/+) and Vim(-/-) mice. However, vimentin was essential to favor Na-glucose cotransporter 1 localization to brush-border membranes and to restore Na-glucose cotransport activity in regenerating tubular cells. We show that the effect of vimentin inactivation is specific and results in persistent glucosuria. We propose that vimentin is part of a structural network that favors carrier localization to plasma membranes to restore transport activity in injured kidneys.

Differentially expressed genes in Populus simonii x P. nigra in respnse to NaCl stress using cDNA-AFLP

USDA-ARS?s Scientific Manuscript database

Salinity is an important environmental factor limiting growth and productivity of plants, and affects almost every aspect of the plant physiology and biochemistry. The objective of this study was to apply cDNA-AFLP and to identify differentially expressed genes in response to NaCl stress vs. no-stre...

Mast cell regulation of Na-glutamine co-transporters B0AT1 in villus and SN2 in crypt cells during chronic intestinal inflammation.

PubMed

Singh, Soudamani; Arthur, Subha; Talukder, Jamilur; Palaniappan, Balasubramanian; Coon, Steven; Sundaram, Uma

2015-04-15

In the chronically inflamed rabbit small intestine, brush border membrane (BBM) Na-glutamine co-transport is inhibited in villus cells (mediated by B0AT1), while it is stimulated in crypt cells (mediated by SN2/SNAT5). How mast cells, known to be enhanced in the chronically inflamed intestine, may regulate B0AT1 in villus and SN2/SNAT5 in crypt cell is unknown. Thus, the aim of the present study is to determine the regulation of B0AT1 and SN2/SNAT5 by mast cells during chronic enteritis. Chronic intestinal inflammation was induced in male rabbits with intra-gastric inoculation of Eimeria magna oocytes. Rabbits with chronic inflammation were treated with ketotifen (10 mg/day) or saline (Placebo) for 2 days. Villus and crypts cells were isolated from the rabbit intestine using the Ca++ chelation technique. Na/K-ATPase activity was measured as Pi from cellular homogenate. BBM vesicles (BBMV) were prepared from villus and crypt cells and uptake studies were performed using rapid filtration technique with (3)H-Glutamine. Western blot analyses were done using B0AT1 and SN2 specific antibodies. In villus cells, Na-glutamine co-transport inhibition observed during inflammation was completely reversed by ketotifen, a mast cell stabilizer. In contrast, in crypt cells, Na-glutamine co-transport stimulation was reversed to normal levels by ketotifen. Kinetic studies demonstrated that ketotifen reversed the inhibition of B0AT1 in villus cells by restoring co-transporter numbers in the BBM, whereas the stimulation of SN2/SNAT5 in crypts cells was reversed secondary to restoration of affinity of the co-transporter. Western blot analysis showed that ketotifen restored immune-reactive levels of B0AT1 in villus cells, while SN2/SNAT5 levels from crypts cell remained unchanged. In the present study we demonstrate that mast cells likely function as a common upstream immune pathway regulator of the Na-dependent glutamine co-transporters, B0AT1 in villus cells and SN2 in crypts cells

Influence of pH and ionic strength (NaCl/Na2SO4) on the reaction HO Cl/ClO- + NO2-

NASA Astrophysics Data System (ADS)

Marcellos da Rosa, M.; Zetzsch, C.

2003-04-01

Equilibria such as HOCl + NO_2^- leftrightarrow ClNO_2 + OH^- and ClNO_2 + H_2O leftrightarrow NO_3^- + 2H^+ + Cl^- play an important role in halogen activation in the troposphere. We studied the oxidation of NO_2^- by HOCl/ClO^- in aqueous phase by stopped-flow measurements at different ionic strengths (bidestilled water, 0.1M NaCl, 1.0M NaCl and 1.0M Na_2SO^4) at various pH values (4.0, 5.5, 6.2 and 10.0) at 293K. The experiments were performed using a SX.18MV Applied Photophysics spectrophotometer, observing the exponential decay of HOCl/ClO^- at λ = 290nm between 10ms and 100s. HOCl (pK_a= 7.50) was obtained by bubbling N_2 with 1% Cl_2 through bidestilled water. The pH of the aqueous solutions of HOCl was determined by a pH meter (CG820, Schott) with a glass electrode N6180 (calibrated with standard buffer solutions at pH = 3.0, 4.0, 7.0 and 10.0), and the pH values were adjusted by dropwise addition of HClO_4 or NaOH. The concentrations of HOCl (ɛHOCl (230nm) = 100M-1cm-1) ([HOCl] = 1.3mM - 10mM) and ClO- (ɛClO- (292nm) = 350 M-1cm-1) ([ClO^-] = 1.3mM - 5mM) were determined by UV spectrometry (Kontron UVIKON 860) at a resolution of 2 nm in 1 cm cells at various pH values. The concentration range of NO_2^- was between 5mM and 50mM. The following second-order rate constant kII were obtained at 293K at various pH values (in units of M-1s-1) in H_2O: pH 4.0, (5.6±0.3)\\cdot 10^3; pH 5.5, (5.0±0.4)\\cdot 10^3; pH 10.0, 3.9±0.4; in 0.1M NaCl: pH 5.5, (4.3±0.4)\\cdot 10^3; pH 10.0, 2.6±0.4; in 1.0M NaCl: pH 5.5, (4.0±0.3); pH 10.0, 0.7±0.2 and in 1.0M Na_2SO_4: pH 5.5, (3.0±0.3)\\cdot 10^3; pH 10.0, 1.9±0.4. There is a strong effect of the pH on the reaction HOCl/ClO^- + NO_2^-, as reflected in the ratio kII_a(pH 5.5, HOCl)/kII_b(pH 10.0, ClO^-): in H_2O (kII_a ˜ 1200 \\cdot kII_b), in 0.1M NaCl (kII_a ˜ 1900 \\cdot kII_b), in 1.0M NaCl (kII_a ˜ 5700 \\cdot kII_b) and in 1.0 M Na_2SO_4 (kII_a ˜ 1500 \\cdot kII_b). A mechanism for the oxidation of NO

Comparative molecular analyses of select pH- and osmoregulatory genes in three freshwater crayfish Cherax quadricarinatus, C. destructor and C. cainii.

PubMed

Ali, Muhammad Y; Pavasovic, Ana; Dammannagoda, Lalith K; Mather, Peter B; Prentis, Peter J

2017-01-01

Systemic acid-base balance and osmotic/ionic regulation in decapod crustaceans are in part maintained by a set of transport-related enzymes such as carbonic anhydrase (CA), Na + /K + -ATPase (NKA), H + -ATPase (HAT), Na + /K + /2Cl - cotransporter (NKCC), Na + /Cl - /HCO[Formula: see text] cotransporter (NBC), Na + /H + exchanger (NHE), Arginine kinase (AK), Sarcoplasmic Ca +2 -ATPase (SERCA) and Calreticulin (CRT). We carried out a comparative molecular analysis of these genes in three commercially important yet eco-physiologically distinct freshwater crayfish , Cherax quadricarinatus, C. destructor and C. cainii , with the aim to identify mutations in these genes and determine if observed patterns of mutations were consistent with the action of natural selection. We also conducted a tissue-specific expression analysis of these genes across seven different organs, including gills, hepatopancreas, heart, kidney, liver, nerve and testes using NGS transcriptome data. The molecular analysis of the candidate genes revealed a high level of sequence conservation across the three Cherax sp. Hyphy analysis revealed that all candidate genes showed patterns of molecular variation consistent with neutral evolution. The tissue-specific expression analysis showed that 46% of candidate genes were expressed in all tissue types examined, while approximately 10% of candidate genes were only expressed in a single tissue type. The largest number of genes was observed in nerve (84%) and gills (78%) and the lowest in testes (66%). The tissue-specific expression analysis also revealed that most of the master genes regulating pH and osmoregulation (CA, NKA, HAT, NKCC, NBC, NHE) were expressed in all tissue types indicating an important physiological role for these genes outside of osmoregulation in other tissue types. The high level of sequence conservation observed in the candidate genes may be explained by the important role of these genes as well as potentially having a number of

Electrical conductivity of low-temperature NaCl-KCl-ZrCl4 melts

NASA Astrophysics Data System (ADS)

Salyulev, A. B.; Khokhlov, V. A.; Red'kin, A. A.

2014-08-01

The dependences of the electrical conductivity of NaCl-KCl-ZrCl4 molten mixtures with a molar ratio NaCl : KCl = 8 : 29 on the temperature (temperature range of 300-540°C) and the ZrCl4 concentration (54.3-75.2 mol %) have been measured for the first time using unique cells.

Secretin stimulates HCO3(-) and acetate efflux but not Na+/HCO3(-) uptake in rat pancreatic ducts.

PubMed

Novak, I; Christoffersen, B C

2001-03-01

Pancreatic ducts secrete HCO3(-), but transport mechanisms are unresolved and possibly vary between species. Our aim was to study the intracellular pH (pHi) regulation and thus H+/HCO3- transport in rat pancreatic ducts. Of particular interest was the Na+/HCO3(-) cotransporter, thought to be important in HCO3(-) -transporting epithelia. pHi was measured with BCECF in freshly isolated intralobular ducts. A reduction in extracellular Na+ concentration or application of HOE 694 (1 microM) decreased pHi by 0.1 to 0.6 pH units, demonstrating Na+/H+ exchanger activity. A reduction in extracellular Cl- concentration or addition of H2DIDS (10 microM) increased pHi by 0.1 to 0.5 pH units, demonstrating Cl-/ HCO(3)- (OH ) exchanger activity. In experimental acidosis, extracellular HCO3(-)/CO2 buffer did not increase the rate of pHi recovery, indicating that provision of HCO3(-) by the Na+/HCO3(-) cotransporter was not apparent. Most importantly, Na+/HCO3(-) cotransport was not stimulated by secretin (1 nM). In contrast, in experimental alkalosis the pHi recovery was increased in HCO3(-)/CO2 buffer, possibly due to Na+/HCO3(-) cotransport in the efflux mode. Secretin (1 nM) and carbachol (1 microM) stimulated HCO3(-) efflux, which can account for the observed HCO3(-) concentrations in rat pancreatic juice. Acetate and HCO3(-) buffers were handled similarly, indicating similar transport mechanisms in pancreatic ducts.

Different blocking effects of HgCl2 and NaCl on aquaporins of pepper plants.

PubMed

Martínez-Ballesta, M Carmen; Diaz, Rafael; Martínez, Vicente; Carvajal, Micaela

2003-12-01

In this study we have compared the short-term effects of both NaCl and HgCl2 on aquaporins of Capsicum annuum L. plants, in order to determine whether or not they are similar. Stomatal conductance, turgor, root hydraulic conductance and water status were measured after 0.5, 2, 4 and 6 h of NaCl (60 mmol/L) or HgCl2 (50 micromol/L) treatment. When 60 mmol/L NaCl was added to the nutrient solution, a large decrease in stomatal conductance was observed after 2 h. However, when HgCl2 (50 micromol/L) was added, the decrease occurred after 4 h. The number of open stomata closed was always lower in plants treated with HgCl2 than in plants treated with NaCl. The water content of the Hg(2+)-treated plants was decreased, compared with controls and NaCl-treated. The root hydraulic conductance decreased after HgCl2 and NaCl treatment plants. Turgor of leaf epidermal cells was greatly reduced in plants treated with HgCl2, but remained constant in the NaCl treatment, compared with control plants. The fact that the stomatal conductance was reduced more rapidly after NaCl addition, followed by the stomatal closure, and that both water content and turgor did not differ from the control suggests that in NaCl-treated plants there must be a signal moving from root to shoot. Therefore, the control of plant homeostasis through a combined regulation of root and stomatal exchanges may be dependent on aquaporin regulation.

A novel sodium bicarbonate cotransporter-like gene in an ancient duplicated region: SLC4A9 at 5q31

PubMed Central

Lipovich, Leonard; Lynch, Eric D; Lee, Ming K; King, Mary-Claire

2001-01-01

Background: Sodium bicarbonate cotransporter (NBC) genes encode proteins that execute coupled Na+ and HCO3- transport across epithelial cell membranes. We report the discovery, characterization, and genomic context of a novel human NBC-like gene, SLC4A9, on chromosome 5q31. Results: SLC4A9 was initially discovered by genomic sequence annotation and further characterized by sequencing of long-insert cDNA library clones. The predicted protein of 990 amino acids has 12 transmembrane domains and high sequence similarity to other NBCs. The 23-exon gene has 14 known mRNA isoforms. In three regions, mRNA sequence variation is generated by the inclusion or exclusion of portions of an exon. Noncoding SLC4A9 cDNAs were recovered multiple times from different libraries. The 3' untranslated region is fragmented into six alternatively spliced exons and contains expressed Alu, LINE and MER repeats. SLC4A9 has two alternative stop codons and six polyadenylation sites. Its expression is largely restricted to the kidney. In silico approaches were used to characterize two additional novel SLC4A genes and to place SLC4A9 within the context of multiple paralogous gene clusters containing members of the epidermal growth factor (EGF), ankyrin (ANK) and fibroblast growth factor (FGF) families. Seven human EGF-SLC4A-ANK-FGF clusters were found. Conclusion: The novel sodium bicarbonate cotransporter-like gene SLC4A9 demonstrates abundant alternative mRNA processing. It belongs to a growing class of functionally diverse genes characterized by inefficient highly variable splicing. The evolutionary history of the EGF-SLC4A-ANK-FGF gene clusters involves multiple rounds of duplication, apparently followed by large insertions and deletions at paralogous loci and genome-wide gene shuffling. PMID:11305939

Physiological responses to salt stress of salt-adapted and directly salt (NaCl and NaCl+Na2SO4 mixture)-stressed cyanobacterium Anabaena fertilissima.

PubMed

Swapnil, Prashant; Rai, Ashwani K

2018-05-01

Soil salinity in nature is generally mixed type; however, most of the studies on salt toxicity are performed with NaCl and little is known about sulfur type of salinity (Na 2 SO 4 ). Present study discerns the physiologic mechanisms responsible for salt tolerance in salt-adapted Anabaena fertilissima, and responses of directly stressed parent cells to NaCl and NaCl+Na 2 SO 4 mixture. NaCl at 500 mM was lethal to the cyanobacterium, whereas salt-adapted cells grew luxuriantly. Salinity impaired gross photosynthesis, electron transport activities, and respiration in parent cells, but not in the salt-adapted cells, except a marginal increase in PSI activity. Despite higher Na + concentration in the salt mixture, equimolar NaCl appeared more inhibitive to growth. Sucrose and trehalose content and antioxidant activities were maximal in 250 mM NaCl-treated cells, followed by salt mixture and was almost identical in salt-adapted (exposed to 500 mm NaCl) and control cells, except a marginal increase in ascorbate peroxidase activity and an additional fourth superoxide dismutase isoform. Catalase isoform of 63 kDa was induced only in salt-stressed cells. Salinity increased the uptake of intracellular Na + and Ca 2+ and leakage of K + in parent cells, while cation level in salt-adapted cells was comparable to control. Though there was differential increase in intracellular Ca 2+ under different salt treatments, ratio of Ca 2+ /Na + remained the same. It is inferred that stepwise increment in the salt concentration enabled the cyanobacterium to undergo priming effect and acquire robust and efficient defense system involving the least energy.

Unique regulation of Na-glutamine cotransporter SN2/SNAT5 in rabbit intestinal crypt cells during chronic enteritis.

PubMed

Singh, Soudamani; Arthur, Subha; Sundaram, Uma

2018-03-01

The only Na-nutrient cotransporter described in mammalian small intestinal crypt cells is SN2/SNAT5, which facilitates glutamine uptake. In a rabbit model of chronic intestinal inflammation, SN2 stimulation is secondary to an increase in affinity of the cotransporter for glutamine. However, the immune regulation of SN2 in the crypt cells during chronic intestinal inflammation is unknown. We sought to determine the mechanism of regulation of Na-nutrient cotransporter SN2 by arachidonic acid metabolites in crypt cells. The small intestines of New Zealand white male rabbits were inflamed via inoculation with Eimeria magna oocytes. After 2-week incubation, control and inflamed rabbits were subjected to intramuscular injections of arachidonyl trifluoromethyl ketone (ATK), piroxicam and MK886 for 48 hrs. After injections, the rabbits were euthanized and crypt cells from small intestines were harvested and used. Treatment of rabbits with ATK prevented the release of AA and reversed stimulation of SN2. Inhibition of cyclooxygenase (COX) with piroxicam did not affect stimulation of SN2. However, inhibition of lipoxygenase (LOX) with MK886, thus reducing leukotriene formation during chronic enteritis, reversed the stimulation of SN2. Kinetic studies showed that the mechanism of restoration of SN2 by ATK or MK886 was secondary to the restoration of the affinity of the cotransporter for glutamine. For all treatment conditions, Western blot analysis revealed no change in SN2 protein levels. COX inhibition proved ineffective at reversing the stimulation of SN2. Thus, this study provides evidence that SN2 stimulation in crypt cells is mediated by the leukotriene pathway during chronic intestinal inflammation. © 2017 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.

PDGF activates K-Cl cotransport through phosphoinositide 3-kinase and protein phosphatase-1 in primary cultures of vascular smooth muscle cells.

PubMed

Zhang, Jing; Lauf, Peter K; Adragna, Norma C

2005-07-15

K-Cl cotransport (K-Cl COT, KCC) is an electroneutrally coupled movement of K and Cl present in most cells. In this work, we studied the pathways of regulation of K-Cl COT by platelet-derived growth factor (PDGF) in primary cultures of vascular smooth muscle cells (VSMCs). Wortmannin and LY 294002 blocked the PDGF-induced K-Cl COT activation, indicating that the phosphoinositide 3-kinase (PI 3-K) pathway is involved. However, PD 98059 had no effect on K-Cl COT activation by PDGF, suggesting that the mitogen-activated protein kinase pathway is not involved under the experimental conditions tested. Involvement of phosphatases was also examined. Sodium orthovanadate, cyclosporin A and okadaic acid had no effect on PDGF-stimulated K-Cl COT. Calyculin A blocked the PDGF-stimulated K-Cl COT by 60%, suggesting that protein phosphatase-1 (PP-1) is a mediator in the PDGF signaling pathway/s. In conclusion, our results indicate that the PDGF-mediated pathways of K-Cl COT regulation involve the signaling molecules PI 3-K and PP-1.

Expression of the sodium potassium chloride cotransporter (NKCC1) and sodium chloride cotransporter (NCC) and their effects on rat lens transparency.

PubMed

Chee, K N; Vorontsova, I; Lim, J C; Kistler, J; Donaldson, P J

2010-05-04

To characterize the expression patterns of the Na+-K+-Cl(-) cotransporter (NKCC) 1 and NKCC2, and the Na+-Cl(-) cotransporter (NCC) in the rat lens and to determine if they play a role in regulating lens volume and transparency. RT-PCR was performed on RNA extracted from fiber cells to identify sodium dependent cotransporters expressed in the rat lens. Western blotting and immunohistochemistry, using NKCC1, NKCC2, and NCC antibodies, were used to verify expression at the protein level and to localize transporter expression. Organ cultured rat lenses were incubated in Artificial Aqueous Humor (AAH) of varying osmolarities or isotonic AAH that contained either the NKCC specific inhibitor bumetanide, or the NCC specific inhibitor thiazide for up to 18 h. Lens transparency was monitored with dark field microscopy, while tissue morphology and antibody labeling patterns were recorded using a confocal microscope. Molecular experiments showed that NKCC1 and NCC were expressed in the lens at both the transcript and protein levels, but NKCC2 was not. Immunohistochemistry showed that both NKCC1 and NCC were expressed in the lens cortex, but NCC expression was also found in the lens core. In the lens cortex the majority of labeling for both transporters was cytoplasmic in nature, while in the lens core, NCC labeling was associated with the membrane. Exposure of lenses to either hypotonic or hypertonic AAH had no noticeable effects on the predominantly cytoplasmic location of either transporter in the lens cortex. Incubation of lenses in isotonic AAH plus the NKCC inhibitor bumetanide for 18 h induced a cortical opacity that was initiated by a shrinkage of peripheral fiber cells and the dilation of the extracellular space between fiber cells in a deeper zone located some approximately 150 microm in from the capsule. In contrast, lenses incubated in isotonic AAH and the NCC inhibitor thiazide maintained both their transparency and their regular fiber cell morphology. We have

Effects of low environmental salinity on the cellular profiles and expression of Na+, K+-ATPase and Na+, K+, 2Cl- cotransporter 1 of branchial mitochondrion-rich cells in the juvenile marine fish Monodactylus argenteus.

PubMed

Kang, Chao-Kai; Liu, Fu-Chen; Chang, Wen-Been; Lee, Tsung-Han

2012-06-01

The goal of this study was to determine the osmoregulatory ability of a juvenile marine fish, silver moony (Monodactylus argenteus), for the purpose of developing a new experimental species for ecophysiological research. In this study, M. argenteus was acclimated to freshwater (FW), brackish water (BW), or seawater (SW). The salinity tolerance of this euryhaline species was effective, and the fish survived well upon osmotic challenges. The largest apical surface of mitochondrion-rich cells was found in the FW individuals. Immunohistochemical staining revealed that Na(+), K(+)-ATPase immunoreactive (NKA-IR) cells were distributed in the interlamellar region of the gill filaments of the silver moony in all experimental groups. In addition to the filaments, NKA-IR cells were also found in the lamellae of the FW individuals. The number of NKA-IR cells in the gills of the FW individuals exceeded that of the BW and SW individuals. The NKA-IR cells of FW and SW individuals exhibited bigger size than that of BW fish. The NKA activities and protein expression of the NKA α-subunit in the gills of the FW individuals were significantly higher than in the BW and SW groups. Additionally, the relative amounts of Na(+), K(+), 2Cl(-) cotransporter 1 (NKCC1) were salinity-dependent in the gills. Immunofluorescent signals of NKCC1 were localized to the basolateral membrane of NKA-IR cells in all groups. In the gills of the FW individuals, however, some NKA-IR cells did not exhibit a basolateral NKCC1 signal. In conclusion, the present study illustrated the osmoregulatory mechanisms of this easy- and economic-to-rear marine teleost with euryhaline capacity and proved the silver moony to be a good experimental animal.

Secretory NaCl and volume flow in renal tubules.

PubMed

Beyenbach, K W

1986-05-01

This review attempts to give a retrospective survey of the available evidence concerning the secretion of NaCl and fluid in renal tubules of the vertebrate kidney. In the absence of glomerular filtration, epithelial secretory mechanisms, which to this date have not been elucidated, are responsible for the renal excretion of NaCl and water in aglomerular fish. However, proximal tubules isolated from glomerular fish kidneys of the flounder, killifish, and the shark also have the capacity to secrete NaCl and fluid. In shark proximal tubules, fluid secretion appears to be driven via secondary active transport of Cl. In another marine vertebrate, the sea snake, secretion of Na (presumably NaCl) and fluid is observed in freshwater-adapted and water-loaded animals. Proximal tubules of mammals can be made to secrete NaCl in vitro together with secretion of aryl acids. An epithelial cell line derived from dog kidney exhibits secondary active secretion of Cl when stimulated with catecholamines. Tubular secretion of NaCl and fluid may serve a variety of renal functions, all of which are considered here. The occurrence of NaCl and fluid secretion in glomerular proximal tubules of teleosts, elasmobranchs, and reptiles and in mammalian renal tissue cultures suggests that the genetic potential for NaCl secretion is present in every vertebrate kidney.

Hypotonic Shock Modulates Na+ Current via a Cl- and Ca2+/Calmodulin Dependent Mechanism in Alveolar Epithelial Cells

PubMed Central

Tatur, Sabina; Brochiero, Emmanuelle; Grygorczyk, Ryszard; Berthiaume, Yves

2013-01-01

Alveolar epithelial cells are involved in Na+ absorption via the epithelial Na+ channel (ENaC), an important process for maintaining an appropriate volume of liquid lining the respiratory epithelium and for lung oedema clearance. Here, we investigated how a 20% hypotonic shock modulates the ionic current in these cells. Polarized alveolar epithelial cells isolated from rat lungs were cultured on permeant filters and their electrophysiological properties recorded. A 20% bilateral hypotonic shock induced an immediate, but transient 52% rise in total transepithelial current and a 67% increase in the amiloride-sensitive current mediated by ENaC. Amiloride pre-treatment decreased the current rise after hypotonic shock, showing that ENaC current is involved in this response. Since Cl- transport is modulated by hypotonic shock, its contribution to the basal and hypotonic-induced transepithelial current was also assessed. Apical NPPB, a broad Cl- channel inhibitor and basolateral DIOA a potassium chloride co-transporter (KCC) inhibitor reduced the total and ENaC currents, showing that transcellular Cl- transport plays a major role in that process. During hypotonic shock, a basolateral Cl- influx, partly inhibited by NPPB is essential for the hypotonic-induced current rise. Hypotonic shock promoted apical ATP secretion and increased intracellular Ca2+. While apyrase, an ATP scavenger, did not inhibit the hypotonic shock current response, W7 a calmodulin antagonist completely prevented the hypotonic current rise. These results indicate that a basolateral Cl- influx as well as Ca2+/calmodulin, but not ATP, are involved in the acute transepithelial current rise elicited by hypotonic shock. PMID:24019969

Functional expression of the Na-K-2Cl cotransporter NKCC2 in mammalian cells fails to confirm the dominant-negative effect of the AF splice variant.

PubMed

Hannemann, Anke; Christie, Jenny K; Flatman, Peter W

2009-12-18

The renal bumetanide-sensitive Na-K-2Cl cotransporter (NKCC2) is the major salt transport pathway in the apical membrane of the mammalian thick ascending limb. It is differentially spliced and the three major variants (A, B, and F) differ in their localization and transport characteristics. Most knowledge about its regulation comes from experiments in Xenopus oocytes as NKCC2 proved difficult to functionally express in a mammalian system. Here we report the cloning and functional expression of untagged and unmodified versions of the major splice variants from ferret kidney (fNKCC2A, -B, and -F) in human embryonic kidney (HEK) 293 cells. Many NKCC2 antibodies used in this study detected high molecular weight forms of the transfected proteins, probably NKCC2 dimers, but not the monomers. Interestingly, monomers were strongly detected by phosphospecific antibodies directed against phosphopeptides in the regulatory N terminus. Bumetanide-sensitive (86)Rb uptake was significantly higher in transfected HEK-293 cells and could be stimulated by incubating cells in a medium containing a low chloride concentration prior the uptake measurements. fNKCC2 was less sensitive to the reduction in chloride concentration than NKCC1. Using HEK-293 cells stably expressing fNKCC2A we also show that co-expression of variant NKCC2AF does not have the dominant-negative effect on NKCC2A activity that was seen in Xenopus oocytes, nor is it trafficked to the cell surface. In addition, fNKCC2AF is neither complex glycosylated nor phosphorylated in its N terminus regulatory region like other variants.

Taste-independent nutrient selection is mediated by a brain-specific Na+/solute cotransporter in Drosophila

PubMed Central

Dus, Monica; Ai, Minrong; Suh, Greg S. B.

2013-01-01

Animals can determine the nutritional value of sugar without the influence of taste. Here, we describe a Drosophila mutant that is insensitive to the nutritional value of sugars, but responds only to the concentration (i.e. sweetness). The affected gene encodes a sodium/solute cotransporter-like protein, designated dSLC5A11 (or cupcake), which is structurally similar to mammalian sodium/glucose cotransporters (SGLTs) that transport sugar across the intestinal and renal lumen. However, dSLC5A11 is prominently expressed in 10-13 pairs of R4 neurons of the ellipsoid body (EB) in the brain and functions in these neurons for selecting appropriate foods. We propose that dSLC5A11 and EB R4 neurons carry out a critical signaling function in responding to internal glycemic levels. PMID:23542692

Regulation of Na+-K+-2Cl− cotransport by protein phosphorylation in ferret erythrocytes

PubMed Central

Flatman, Peter W; Creanor, James

1999-01-01

Na+-K+-2Cl− cotransport in ferret erythrocytes was measured as the bumetanide-sensitive uptake of 86Rb. The resting cotransport rate was high but could be increased threefold by treating erythrocytes with calyculin A, a potent inhibitor of serine/threonine phosphatases. Twenty nanomolar was sufficient to maximally and rapidly (within 4 min) stimulate transport. The effects of several kinase inhibitors were tested. High concentrations of K-252a, K-252b, calphostin C and hypericin caused less than 20 % inhibition. Staurosporine (IC50, 0.06 μm) and 4-amino-5-(4-methylphenyl)-7-(t-butyl)pyrazolo[3,4-d]pyrimidine (PP1; IC50, 2.5 μm) were more potent but still only partially (40–50 %) inhibited transport, an effect mimicked by reducing ionized intracellular Mg2+ concentration to submicromolar levels. Genistein may inhibit all transport at a sufficiently high dose (IC50, 0.36 mM) perhaps by directly inhibiting the transporter. Staurosporine, PP1 and the removal of Mg2+ all prevented subsequent stimulation by calyculin A, and all inhibited calyculin-stimulated transport by 20–30 %. The effects of staurosporine, PP1 and Mg2+ removal were not additive. The phosphatase that dephosphorylates the cotransporter is probably Mg2+ (or possibly Ca2+ or Mn2+) sensitive and not the target for calyculin A. The data suggest that this phosphatase is inhibited by phosphorylation, and that it is the regulation of this process which is affected by calyculin A and the kinase inhibitors tested here. Phosphorylation of the phosphatase is probably regulated by members of the Src family of tyrosine kinases. PMID:10358111

Kinetin Reversal of NaCl Effects

PubMed Central

Katz, Adriana; Dehan, Klara; Itai, Chanan

1978-01-01

Leaf discs of Nicotiana rustica L. were floated on NaCl in the presence of kinetin or abscisic acid. On the 5th day 14CO2 fixation, [3H]leucine incorporation, stomatal conductance, and chlorophyll content were determined. Kinetin either partially or completely reversed the inhibitory effects of NaCl while ABA had no effect. PMID:16660618

Expression of an alfalfa (Medicago sativa L.) peroxidase gene in transgenic Arabidopsis thaliana enhances resistance to NaCl and H2O2.

PubMed

Teng, K; Xiao, G Z; Guo, W E; Yuan, J B; Li, J; Chao, Y H; Han, L B

2016-05-23

Peroxidases (PODs) are enzymes that play important roles in catalyzing the reduction of H2O2 and the oxidation of various substrates. They function in many different and important biological processes, such as defense mechanisms, immune responses, and pathogeny. The POD genes have been cloned and identified in many plants, but their function in alfalfa (Medicago sativa L.) is not known, to date. Based on the POD gene sequence (GenBank accession No. L36157.1), we cloned the POD gene in alfalfa, which was named MsPOD. MsPOD expression increased with increasing H2O2. The gene was expressed in all of the tissues, including the roots, stems, leaves, and flowers, particularly in stems and leaves under light/dark conditions. A subcellular analysis showed that MsPOD was localized outside the cells. Transgenic Arabidopsis with MsPOD exhibited increased resistance to H2O2 and NaCl. Moreover, POD activity in the transgenic plants was significantly higher than that in wild-type Arabidopsis. These results show that MsPOD plays an important role in resistance to H2O2 and NaCl.

"JCE" Classroom Activity Connections: NaCl or CaCl[subscript 2], Smart Polymer Gel Tells More

ERIC Educational Resources Information Center

Chen, Yueh-Huey; Lin, Jia-Ying; Wang, Yu-Chen; Yaung, Jing-Fun

2010-01-01

This classroom activity connection demonstrates the differences between the effects of NaCl (a salt of monovalent metal ions) and CaCl[subscript 2] (a salt of polyvalent metal ions) on swollen superabsorbent polymer gels. Being ionic compounds, NaCl and CaCl[subscript 2] both collapse the swollen polymer gels. The gel contracted by NaCl reswells…

High Pressure Strength Study on NaCl

NASA Astrophysics Data System (ADS)

Mi, Z.; Shieh, S. R.; High Pressure Mineral Physics Group

2010-12-01

Yield strength is regarded as one important property related to rheological characteristics of minerals in the Earth’s interior. The strength study of NaCl, a popular pressure medium in static high pressure experiments, has been carried out under non-hydrostatic conditions in a diamond anvil cell up to 43 GPa at room temperature using radial energy dispersive X-ray diffraction technique. Phase transformation from B1 (rock salt structure) to B2 (CsCl structure) starts at 29.4 GPa, and is complete at 32.1 GPa. Bulk modulus obtained by third order Birch-Manurgham equation of state is 25.5 GPa with pressure derivative 4.6 for B1 phase, and 30.78 GPa with pressure derivative 4.32 GPa for B2 phase, which are in a good agreement with previous studies. The differential stress of NaCl B1 phase shows very gentle increase with pressure, which indicates that NaCl is a very good pressure-transmitting medium at pressure below 30 GPa. However, the differential stress increases more abruptly for B2 phase and this may imply that NaCl can no longer be regarded as a “soft” pressure medium at very high pressures. For B1 phase, (111) is the strongest plane and (200) is the weakest plane, while (200) becomes the strongest plane in B2 phase. Pure NaCl is weaker than mixture MgO and NaCl, which indicates that soft material become stronger when mixed with hard material. The yield strength of B2 obtained through energy dispersive X-ray diffraction technique increase linearly, while the value derived by pressure gradient method shows jagged trend.

Electron scattering in graphene with adsorbed NaCl nanoparticles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Drabińska, Aneta, E-mail: Aneta.Drabinska@fuw.edu.pl; Kaźmierczak, Piotr; Bożek, Rafał

2015-01-07

In this work, the results of contactless magnetoconductance and Raman spectroscopy measurements performed for a graphene sample after its immersion in NaCl solution were presented. The properties of the immersed sample were compared with those of a non-immersed reference sample. Atomic force microscopy and electron spin resonance experiments confirmed the deposition of NaCl nanoparticles on the graphene surface. A weak localization signal observed using contactless magnetoconductance showed the reduction of the coherence length after NaCl treatment of graphene. Temperature dependence of the coherence length indicated a change from ballistic to diffusive regime in electron transport after NaCl treatment. The mainmore » inelastic scattering process was of the electron-electron type but the major reason for the reduction of the coherence length at low temperatures was additional, temperature independent, inelastic scattering. We associate it with spin flip scattering, caused by NaCl nanoparticles present on the graphene surface. Raman spectroscopy showed an increase in the D and D′ bands intensities for graphene after its immersion in NaCl solution. An analysis of the D, D′, and G bands intensities proved that this additional scattering is related to the decoration of vacancies and grain boundaries with NaCl nanoparticles, as well as generation of new on-site defects as a result of the decoration of the graphene surface with NaCl nanoparticles. The observed energy shifts of 2D and G bands indicated that NaCl deposition on the graphene surface did not change carrier concentration, but reduced compressive biaxial strain in the graphene layer.« less

23Na and 35/37Cl as NMR probes of growth and shape of sodium taurodeoxycholate micellar aggregates in the presence of NaCl.

PubMed

Asaro, Fioretta; Feruglio, Luigi; Galantini, Luciano; Nardelli, Alessia

2013-02-15

The growth of the aggregates of the dihydroxylated bile salt sodium taurodeoxycholate (NaTDC) upon NaCl addition and the involvement of the counterion were investigated by NMR spectroscopy of monoatomic ionic species. (23)Na T(1) values from 0.015, 0.100, and 0.200 mol kg(-1) NaTDC solutions in D(2)O, at variable NaCl content, proved to be sensitive to the transition from primary to secondary aggregates, which occurs in the former sample, and to intermicellar interaction. Some (79)Br NMR measurements were performed on a 0.100 mol kg(-1) NaTDC sample added by NaBr in place of NaCl for comparison purposes. The (23)Na, (35)Cl, and (37)Cl double quantum filtered (DQF) patterns, from the 0.100 mol kg(-1) NaTDC sample, and (23)Na ones also from the 0.200 mol kg(-1) NaTDC one, in the presence of 0.750 mol kg(-1) NaCl, are a clear manifestation of motional anisotropy. Moreover, the DQF spectra of (23)Na and (37)Cl, which possess close quadrupole moments, display a striking similarity. The DQF lineshapes were simulated exploiting the Scilab environment to obtain an estimate of the residual quadrupole splitting magnitude. These results support the description of NaTDC micelles as cylindrical aggregates, strongly interacting at high ionic strengths, and capable of association with added electrolytes. Copyright © 2012 Elsevier Inc. All rights reserved.

NaCl intake and preference threshold of spontaneously hypertensive rats.

PubMed

Fregly, M J

1975-09-01

Both male and female spontaneously hypertensive (SH) rats have an appetite for NaCl solution. The appetite is present when a choice is offered between distilled water and either isotonic or hypertonic (0.25 M) NaCl solution to drink. Total fluid intake (water plus NaCl solution) was greater for SH rats than for controls while food intakes (g/100 g body wt/day) of SH rats were not different from controls. Mean body weight of SH rats was always less than that of controls. The appetite for NaCl solution was accompanied by a significant reduction in preference (detection) threshold. SH rats could detect the difference between distilled water and NaCl solution when the concentration of the latter was 12 mEq/liter compared to a control threshold of 30 mEq/liter. The NaCl appetite and reduced NaCl preference threshold induced by spontaneous hypertension is in marked contrast to the NaCl aversion induced by other types of experimentally induced hypertension in rats. The mechanism or mechanisms responsible for these differences remain for further study.

Temperature invariance of NaCl solubility in water: inferences from salt-water cluster behavior of NaCl, KCl, and NH4Cl.

PubMed

Bharmoria, Pankaj; Gupta, Hariom; Mohandas, V P; Ghosh, Pushpito K; Kumar, Arvind

2012-09-27

The growth and stability of salt-water clusters have been experimentally studied in aqueous solutions of NaCl, KCl, and NH(4)Cl from dilute to near-saturation conditions employing dynamic light scattering and zeta potential measurements. In order to examine cluster stability, the changes in the cluster sizes were monitored as a function of temperature. Compared to the other cases, the average size of NaCl-water clusters remained almost constant over the studied temperature range of 20-70 °C. Information obtained from the temperature-dependent solution compressibility (determined from speed of sound and density measurements), multinuclear NMR ((1)H, (17)O, (35)Cl NMR), and FTIR were utilized to explain the cluster behavior. Comparison of NMR chemical shifts of saturated salt solutions with solid-state NMR data of pure salts, and evaluation of spectral modifications in the OH stretch region of saturated salt solutions as compared to that of pure water, provided important clues on ion pair-water interactions and water structure in the clusters. The high stability and temperature independence of the cluster sizes in aqueous NaCl shed light on the temperature invariance of its solubility.

The membrane trafficking and functionality of the K+-Cl- co-transporter KCC2 is regulated by TGF-β2.

PubMed

Roussa, Eleni; Speer, Jan Manuel; Chudotvorova, Ilona; Khakipoor, Shokoufeh; Smirnov, Sergei; Rivera, Claudio; Krieglstein, Kerstin

2016-09-15

Functional activation of the neuronal K(+)-Cl(-) co-transporter KCC2 (also known as SLC12A5) is a prerequisite for shifting GABAA responses from depolarizing to hyperpolarizing during development. Here, we introduce transforming growth factor β2 (TGF-β2) as a new regulator of KCC2 membrane trafficking and functional activation. TGF-β2 controls membrane trafficking, surface expression and activity of KCC2 in developing and mature mouse primary hippocampal neurons, as determined by immunoblotting, immunofluorescence, biotinylation of surface proteins and KCC2-mediated Cl(-) extrusion. We also identify the signaling pathway from TGF-β2 to cAMP-response-element-binding protein (CREB) and Ras-associated binding protein 11b (Rab11b) as the underlying mechanism for TGF-β2-mediated KCC2 trafficking and functional activation. TGF-β2 increases colocalization and interaction of KCC2 with Rab11b, as determined by 3D stimulated emission depletion (STED) microscopy and co-immunoprecipitation, respectively, induces CREB phosphorylation, and enhances Rab11b gene expression. Loss of function of either CREB1 or Rab11b suppressed TGF-β2-dependent KCC2 trafficking, surface expression and functionality. Thus, TGF-β2 is a new regulatory factor for KCC2 functional activation and membrane trafficking, and a putative indispensable molecular determinant for the developmental shift of GABAergic transmission. © 2016. Published by The Company of Biologists Ltd.

Differential expression of gill Na+,K+-ATPaseα - and β-subunits, Na+,K+,2Cl- cotransporter and CFTR anion channel in juvenile anadromous and landlocked Atlantic salmon Salmo salar

USGS Publications Warehouse

Nilsen, Tom O.; Ebbesson, Lars O.E.; Madsen, Steffen S.; McCormick, Stephen D.; Andersson, Eva; Bjornsson, Bjorn Thrandur; Prunet, Patrick; Stefansson, Sigurd O.

2007-01-01

This study examines changes in gill Na+,K+-ATPase (NKA) α- and β-subunit isoforms, Na+,K+,2Cl- cotransporter (NKCC) and cystic fibrosis transmembrane conductance regulator (CFTR I and II) in anadromous and landlocked strains of Atlantic salmon during parr-smolt transformation, and after seawater (SW) transfer in May/June. Gill NKA activity increased from February through April, May and June among both strains in freshwater (FW), with peak enzyme activity in the landlocked salmon being 50% below that of the anadromous fish in May and June. Gill NKA-α1b, -α3, -β1 and NKCC mRNA levels in anadromous salmon increased transiently, reaching peak levels in smolts in April/May, whereas no similar smolt-related upregulation of these transcripts occurred in juvenile landlocked salmon. Gill NKA-α1a mRNA decreased significantly in anadromous salmon from February through June, whereas α1a levels in landlocked salmon, after an initial decrease in April, remained significantly higher than those of the anadromous smolts in May and June. Following SW transfer, gill NKA-α1b and NKCC mRNA increased in both strains, whereas NKA-α1a decreased. Both strains exhibited a transient increase in gill NKA α-protein abundance, with peak levels in May. Gill α-protein abundance was lower in SW than corresponding FW values in June. Gill NKCC protein abundance increased transiently in anadromous fish, with peak levels in May, whereas a slight increase was observed in landlocked salmon in May, increasing to peak levels in June. Gill CFTR I mRNA levels increased significantly from February to April in both strains, followed by a slight, though not significant increase in May and June. CFTR I mRNA levels were significantly lower in landlocked than anadromous salmon in April/June. Gill CFTR II mRNA levels did not change significantly in either strain. Our findings demonstrates that differential expression of gill NKA-α1a, -α1b and -α3 isoforms may be important for potential functional

AT2R (Angiotensin II Type 2 Receptor)-Mediated Regulation of NCC (Na-Cl Cotransporter) and Renal K Excretion Depends on the K Channel, Kir4.1.

PubMed

Wu, Peng; Gao, Zhong-Xiuzi; Duan, Xin-Peng; Su, Xiao-Tong; Wang, Ming-Xiao; Lin, Dao-Hong; Gu, Ruimin; Wang, Wen-Hui

2018-04-01

AT2R (AngII [angiotensin II] type 2 receptor) is expressed in the distal nephrons. The aim of the present study is to examine whether AT2R regulates NCC (Na-Cl cotransporter) and Kir4.1 of the distal convoluted tubule. AngII inhibited the basolateral 40 pS K channel (a Kir4.1/5.1 heterotetramer) in the distal convoluted tubule treated with losartan but not with PD123319. AT2R agonist also inhibits the K channel, indicating that AT2R was involved in tonic regulation of Kir4.1. The infusion of PD123319 stimulated the expression of tNCC (total NCC) and pNCC (phosphorylated NCC; Thr 53 ) by a time-dependent way with the peak at 4 days. PD123319 treatment (4 days) stimulated the basolateral 40 pS K channel activity, augmented the basolateral K conductance, and increased the negativity of distal convoluted tubule membrane. The stimulation of Kir4.1 was essential for PD123319-induced increase in NCC because inhibiting AT2R increased the expression of tNCC and pNCC only in wild-type but not in the kidney-specific Kir4.1 knockout mice. Renal clearance study showed that thiazide-induced natriuretic effect was larger in PD123319-treated mice for 4 days than untreated mice. However, this effect was absent in kidney-specific Kir4.1 knockout mice which were also Na wasting under basal conditions. Finally, application of AT2R antagonist decreased the renal ability of K excretion and caused hyperkalemia in wild-type but not in kidney-specific Kir4.1 knockout mice. We conclude that AT2R-dependent regulation of NCC requires Kir4.1 in the distal convoluted tubule and that AT2R plays a role in stimulating K excretion by inhibiting Kir4.1 and NCC. © 2018 American Heart Association, Inc.

Molecular characterization of Na+/K+/2Cl- cotransporter 1 alpha from Trachinotus ovatus (Linnaeus, 1758) and its expression responses to acute salinity stress.

PubMed

Zhao, Chao-Ping; Guo, Hua-Yang; Zhu, Ke-Cheng; Guo, Liang; Zhang, Nan; Liu, Bao-Suo; Yang, Jing-Wen; Liu, Bo; Jiang, Shi-Gui; Zhang, Dian-Chang

2018-06-06

Trachinotus ovatus is widely cultured in the ponds and gulf on the southeast coast of China. The dramatic salinity decrease caused by heavy rainfall could cause mass mortality of T. ovatus in aquaculture. It is very important to understand the osmoregulatory mechanism of T. ovatus. Na + /K + /2Cl - cotransporter 1a (NKCC1a) is involved in the osmoregulation of fish and plays a crucial role in cell volume homeostasis and maintenance of the electrolyte content. In this study, we characterized nkcc1a (designed as Tonkcc1a) from T. ovatus and investigated its expression responses to acute salinity changes. Tonkcc1a is approximately 70 kb in length and contains 26 exons and 25 introns. The phylogenetic analysis confirmed that ToNKCC1a belonged to the NKCC1a subclade. Quantitative real-time (qRT-PCR) analysis indicated that Tonkcc1a was ubiquitously expressed in all examined tissues, with the highest mRNA levels observed in gills, and the lowest level in liver. When T. ovatus were transferred from seawater (30‰) into fresh water, the expression levels of Tonkcc1a mRNA were significantly downregulated in gills and kidney, whereas its expression level was markedly upregulated in intestine. When transferred from seawater (30‰) to 10‰ sea water, the expression levels of Tonkcc1a mRNA were clearly increased in gills and kidney. When transferred from seawater (30‰) to 20‰ sea water, the expression of Tonkcc1a mRNA increased to some extent in gills, kidney, and intestine. When transferred from seawater (30‰) to 40‰ sea water, the expression levels of Tonkcc1a mRNA were dramatically upregulated in gills and intestine compared to that in the control. These results suggested that Tonkcc1a was involved in the response to acute salinity changes. Copyright © 2018 Elsevier Inc. All rights reserved.

Spray-dried chitosan/acid/NaCl microparticles enhance saltiness perception.

PubMed

Yi, Cheng; Tsai, Min-Lang; Liu, Tristan

2017-09-15

The composition, physicochemical properties and salinity of spray-dried chitosan/acid/NaCl microparticles were tested to ensure a low-sodium and high-salinity salty agent. The spray-dried chitosan/acid/NaCl microparticles were hollow and had a favourable hygroscopicity, and increased NaCl content and decreased organic acid content. Their size of the microparticles was 15.4-32.0μm and increased with NaCl concentration. The microparticles of acetic and lactic acid groups had a NaCl crystal size of 1-2 and 1-4μm, respectively. The NaCl crystals of acetic, lactic and citric acid group microparticles were distributed on the microparticle matrices, mostly on the microparticle surface and mainly on the inner walls of the microparticles walls, respectively. The acetic and lactic acid group microparticles were relatively smaller than general salt, with NaCl crystals distributed on the particle surfaces. Consequently, they were perceived as saltier than general salt and could potentially be regarded as a low-sodium salt for surface-salted foods. Copyright © 2017 Elsevier Ltd. All rights reserved.

Plasma-membrane H(+)-ATPase gene expression is regulated by NaCl in cells of the halophyte Atriplex nummularia L.

PubMed

Niu, X; Zhu, J K; Narasimhan, M L; Bressan, R A; Hasegawa, P M

1993-01-01

An Atriplex nummularia L. cDNA probe encoding the partial sequence of an isoform of the plasma-membrane H(+)-ATPase was isolated, and used to characterize the NaCl regulation of mRNA accumulation in cultured cells of this halophyte. The peptide (477 amino acids) translated from the open reading frame has the highest sequence homology to the Nicotiana plumbaginifolia plasma-membrane H(+)-ATPase isoform pma4 (greater than 80% identity) and detected a transcript of approximately 3.7 kb on Northern blots of both total and poly(A)+ RNA. The mRNA levels were comparable in unadapted cells, adapted cells (cells adapted to and growing in 342 mM NaCl) and deadapted cells (cells previously adapted to 342 mM NaCl that are now growing without salt). Increased mRNA abundance was detected in deadapted cells within 24 h after exposure to NaCl but not in unadapted cells with similar salt treatments. The NaCl up-regulation of message abundance in deadapted cells was subject to developmental control. Analogous to those reported for glycophytes, the plasma-membrane H(+)-ATPase are encoded by a multigene family in the halophyte.

Na(+)-D-glucose cotransporter in the kidney of Squalus acanthias: molecular identification and intrarenal distribution.

PubMed

Althoff, Thorsten; Hentschel, Hartmut; Luig, Jutta; Schütz, Hendrike; Kasch, Myriam; Kinne, Rolf K-H

2006-04-01

Using primers against conserved regions of mammalian Na(+)-d-glucose cotransporters (SGLT), a cDNA was cloned from the kidney of spiny dogfish shark (Squalus acanthias). On the basis of comparison of amino acid sequence, membrane topology, and putative glycosylation and phosphorylation sites, the cDNA could be shown to belong to the family of sglt genes. Indeed, Na(+)-dependent d-glucose uptake could be demonstrated after expression of the gene in Xenopus laevis oocytes. In a dendrogram, the SGLT from shark kidney has a high homology to the mammalian SGLT2. Computer analysis revealed that the elasmobranch protein is most similar to the mammalian proteins in the transmembrane regions and contains already all the amino acids identified to be functionally important, suggesting early conservation during evolution. Extramembraneous loops show larger variations. This holds especially for loop 13, which has been implied as a phlorizin-binding domain. Antibodies were generated and the intrarenal distribution of the SGLT was studied in cryosections. In parallel, the nephron segments were identified by lectins. Positive immunoreactions were found in the proximal tubule in the early parts PIa and PIb and the late segment PIIb. The large PIIa segment of the proximal tubule showed no reaction. In contrast to the mammalian kidney also the late distal tubule, the collecting tubule, and the collecting duct showed immunoreactivity. The molecular information confirms previous vesicle studies in which a low affinity SGLT with a low stoichiometry has been observed and supports the notion of a similarity of the shark kidney SGLT to the mammalian SGLT2. Despite its presence in the late parts of the nephron, the absence of SGLT in the major part of the proximal tubule, the relatively low affinity, and in particular the low stoichiometry might explain the lack of a T(m) for d-glucose in the shark kidney.

NaCl responsive taste cells in the mouse fungiform taste buds.

PubMed

Yoshida, R; Horio, N; Murata, Y; Yasumatsu, K; Shigemura, N; Ninomiya, Y

2009-03-17

Previous studies have demonstrated that rodents' chorda tympani (CT) nerve fibers responding to NaCl can be classified according to their sensitivities to the epithelial sodium channel (ENaC) blocker amiloride into two groups: amiloride-sensitive (AS) and -insensitive (AI). The AS fibers were shown to respond specifically to NaCl, whereas AI fibers broadly respond to various electrolytes, including NaCl. These data suggest that salt taste transduction in taste cells may be composed of at least two different systems; AS and AI ones. To further address this issue, we investigated the responses to NaCl, KCl and HCl and the amiloride sensitivity of mouse fungiform papilla taste bud cells which are innervated by the CT nerve. Comparable with the CT data, the results indicated that 56 NaCl-responsive cells tested were classified into two groups; 25 cells ( approximately 44%) narrowly responded to NaCl and their NaCl response were inhibited by amiloride (AS cells), whereas the remaining 31 cells ( approximately 56%) responded not only to NaCl, but to KCl and/or HCl and showed no amiloride inhibition of NaCl responses (AI cells). Amiloride applied to the basolateral side of taste cells had no effect on NaCl responses in the AS and AI cells. Single cell reverse transcription-polymerase chain reaction (RT-PCR) experiments indicated that ENaC subunit mRNA was expressed in a subset of AS cells. These findings suggest that the mouse fungiform taste bud is composed of AS and AI cells that can transmit taste information differently to their corresponding types of CT fibers, and apical ENaCs may be involved in the NaCl responses of AS cells.

Growth responses and ion accumulation in the halophytic legume Prosopis strombulifera are determined by Na2SO4 and NaCl.

PubMed

Reginato, M; Sosa, L; Llanes, A; Hampp, E; Vettorazzi, N; Reinoso, H; Luna, V

2014-01-01

Halophytes are potential gene sources for genetic manipulation of economically important crop species. This study addresses the physiological responses of a widespread halophyte, Prosopis strombulifera (Lam.) Benth to salinity. We hypothesised that increasing concentrations of the two major salts present in soils of central Argentina (Na2SO4, NaCl, or their iso-osmotic mixture) would produce distinct physiological responses. We used hydroponically grown P. strombulifera to test this hypothesis, analysing growth parameters, water relations, photosynthetic pigments, cations and anions. These plants showed a halophytic response to NaCl, but strong general inhibition of growth in response to iso-osmotic solutions containing Na2SO4. The explanation for the adaptive success of P. strombulifera in high NaCl conditions seems to be related to a delicate balance between Na(+) accumulation (and its use for osmotic adjustment) and efficient compartmentalisation in vacuoles, the ability of the whole plant to ensure sufficient K(+) supply by maintaining high K(+)/Na(+) discrimination, and maintenance of normal Ca(2+) levels in leaves. The three salt treatments had different effects on the accumulation of ions. Findings in bi-saline-treated plants were of particular interest, where most of the physiological parameters studied showed partial alleviation of SO4(2-)-induced toxicity by Cl(-). Thus, discussions on physiological responses to salinity could be further expanded in a way that more closely mimics natural salt environments. © 2013 German Botanical Society and The Royal Botanical Society of the Netherlands.

Common mechanisms of inhibition for the Na+/glucose (hSGLT1) and Na+/Cl−/GABA (hGAT1) cotransporters

PubMed Central

Hirayama, Bruce A; Díez-Sampedro, Ana; Wright, Ernest M

2001-01-01

Electrophysiological methods were used to investigate the interaction of inhibitors with the human Na+/glucose (hSGLT1) and Na+/Cl−/GABA (hGAT1) cotransporters. Inhibitor constants were estimated from both inhibition of substrate-dependent current and inhibitor-induced changes in cotransporter conformation. The competitive, non-transported inhibitors are substrate derivatives with inhibition constants from 200 nM (phlorizin) to 17 mM (esculin) for hSGLT1, and 300 nM (SKF89976A) to 10 mM (baclofen) for hGAT1. At least for hSGLT1, values determined using either method were proportional over 5-orders of magnitude. Correlation of inhibition to structure of the inhibitors resulted in a pharmacophore for glycoside binding to hSGLT1: the aglycone is coplanar with the pyranose ring, and binds to a hydrophobic/aromatic surface of at least 7×12Å. Important hydrogen bond interactions occur at five positions bordering this surface. In both hSGLT1 and hGAT1 the data suggests that there is a large, hydrophobic inhibitor binding site ∼8Å from the substrate binding site. This suggests an architectural similarity between hSGLT1 and hGAT1. There is also structural similarity between non-competitive and competitive inhibitors, e.g., phloretin is the aglycone of phlorizin (hSGLT1) and nortriptyline resembles SKF89976A without nipecotic acid (hGAT1). Our studies establish that measurement of the effect of inhibitors on presteady state currents is a valid non-radioactive method for the determination of inhibitor binding constants. Furthermore, analysis of the presteady state currents provide novel insights into partial reactions of the transport cycle and mode of action of the inhibitors. PMID:11588102

Heterogeneous reactions of HNO3(g) + NaCl(s) yields HCl(g) + NaNO3(s) and N2O5(g) + NaCl(s) yields ClNO2(g) + NaNO3(s)

NASA Technical Reports Server (NTRS)

Leu, Ming-Taun; Timonen, Raimo S.; Keyser, Leon F.; Yung, Yuk L.

1995-01-01

The heterogeneous reactions of HNO3(g) + NaCl(s) yields HCl(g) + NaNO3(s) (eq 1) and N2O5(g) + NaCl(s) yields ClNO2(g) + NaNO3(S) (eq 2) were investigated over the temperature range 223-296 K in a flow-tube reactor coupled to a quadrupole mass spectrometer. Either a chemical ionization mass spectrometer (CIMS) or an electron-impact ionization mass spectrometer (EIMS) was used to provide suitable detection sensitivity and selectivity. In order to mimic atmospheric conditions, partial pressures of HNO3 and N2O5 in the range 6 x 10(exp -8) - 2 x 10(exp -6) Torr were used. Granule sizes and surface roughness of the solid NaCl substrates were determined by using a scanning electron microscope. For dry NaCl substrates, decay rates of HNO3 were used to obtain gamma(1) = 0.013 +/- 0.004 (1sigma) at 296 K and > 0.008 at 223 K, respectively. The error quoted is the statistical error. After all corrections were made, the overall error, including systematic error, was estimated to be about a factor of 2. HCl was found to be the sole gas-phase product of reaction 1. The mechanism changed from heterogeneous reaction to predominantly physical adsorption when the reactor was cooled from 296 to 223 K. For reaction 2 using dry salts, gamma(2) was found to be less than 1.0 x 10(exp -4) at both 223 and 296 K. The gas-phase reaction product was identified as ClNO2 in previous studies using an infrared spectrometer. An enhancement in reaction probability was observed if water was not completely removed from salt surfaces, probably due to the reaction of N2O5(g) + H2O(s) yields 2HNO3(g). Our results are compared with previous literature values obtained using different experimental techniques and conditions. The implications of the present results for the enhancement of the hydrogen chloride column density in the lower stratosphere after the El Chichon volcanic eruption and for the chemistry of HCl and HNO3 in the marine troposphere are discussed.

The Cathodic Behavior of Ti(III) Ion in a NaCl-2CsCl Melt

NASA Astrophysics Data System (ADS)

Song, Yang; Jiao, Shuqiang; Hu, Liwen; Guo, Zhancheng

2016-02-01

The cathodic behavior of Ti(III) ions in a NaCl-2CsCl melt was investigated by cyclic voltammetry, chronopotentiometry, and square wave voltammetry with a tungsten electrode being the working electrode at different temperatures. The results show that the cathodic behavior of Ti(III) ion consists of two irreversible steps: Ti3+ + e = Ti2+ and Ti2+ + 2 e = Ti. The diffusion coefficient for the Ti(III) ion in the NaCl-2CsCl eutectic is 1.26 × 10-5 cm2 s-1 at 873 K (600 °C), increases to be 5.57 × 10-5 cm2 s-1 at 948K (675°C), and further rises to 10.8 × 10-5 cm2 s-1 at 1023 (750 °C). Moreover, galvanostatic electrolysis performed on a titanium electrode further presents the feasibility of electrodepositing metallic titanium in the molten NaCl-2CsCl-TiCl3 system.

K-Cl Cotransporter 2-mediated Cl- Extrusion Determines Developmental Stage-dependent Impact of Propofol Anesthesia on Dendritic Spines.

PubMed

Puskarjov, Martin; Fiumelli, Hubert; Briner, Adrian; Bodogan, Timea; Demeter, Kornel; Lacoh, Claudia-Marvine; Mavrovic, Martina; Blaesse, Peter; Kaila, Kai; Vutskits, Laszlo

2017-05-01

General anesthetics potentiating γ-aminobutyric acid (GABA)-mediated signaling are known to induce a persistent decrement in excitatory synapse number in the cerebral cortex when applied during early postnatal development, while an opposite action is produced at later stages. Here, the authors test the hypothesis that the effect of general anesthetics on synaptogenesis depends upon the efficacy of GABA receptor type A (GABAA)-mediated inhibition controlled by the developmental up-regulation of the potassium-chloride (K-Cl) cotransporter 2 (KCC2). In utero electroporation of KCC2 was used to prematurely increase the efficacy of (GABAA)-mediated inhibition in layer 2/3 pyramidal neurons in the immature rat somatosensory cortex. Parallel experiments with expression of the inward-rectifier potassium channel Kir2.1 were done to reduce intrinsic neuronal excitability. The effects of these genetic manipulations (n = 3 to 4 animals per experimental group) were evaluated using iontophoretic injection of Lucifer Yellow (n = 8 to 12 cells per animal). The total number of spines analyzed per group ranged between 907 and 3,371. The authors found a robust effect of the developmental up-regulation of KCC2-mediated Cl transport on the age-dependent action of propofol on dendritic spines. Premature expression of KCC2, unlike expression of a transport-inactive KCC2 variant, prevented a propofol-induced decrease in spine density. In line with a reduction in neuronal excitability, the above result was qualitatively replicated by overexpression of Kir2.1. The KCC2-dependent developmental increase in the efficacy of GABAA-mediated inhibition is a major determinant of the age-dependent actions of propofol on dendritic spinogenesis.

The Salty Scrambled Egg: Detection of NaCl Toward CRL 2688

NASA Astrophysics Data System (ADS)

Highberger, J. L.; Thomson, K. J.; Young, P. A.; Arnett, D.; Ziurys, L. M.

2003-08-01

NaCl has been detected toward the circumstellar envelope of the post-AGB star CRL 2688 using the IRAM 30 m telescope, the first time this molecule has been identified in a source other than IRC +10216. The J=7-->6, 11-->10, 12-->11, and 18-->17 transitions of NaCl at 1, 2, and 3 mm have been observed, as well as the J=8-->7 line of the 37Cl isotopomer. The J=12-->11 line was also measured at the ARO 12 m telescope. An unsuccessful search was additionally conducted for AlCl toward CRL 2688, although in the process new transitions of NaCN were observed. Both NaCl and NaCN were found to be present in the AGB remnant wind, as suggested by their U-shaped line profiles, indicative of emission arising from an optically thin, extended shell-like source of radius ~10"-12". These data contrast with past results in IRC +10216, where the distribution of both molecules is confined to within a few arcseconds of the star. A high degree of excitation is required for the transitions observed for NaCl and NaCN; therefore, these two species likely arise in the region where the high-velocity outflow has collided with the remnant wind. Here the effects of shocks and clumping due to Rayleigh-Taylor instabilities have raised the densities and temperatures significantly. The shell source is thus likely to be clumpy and irregular. The chemistry producing the sodium compounds is consequently more complex than simple LTE formation. Abundances of NaCl and NaCN, relative to H2, are f~1.6×10-10 and ~5.2×10-9, respectively, while the upper limit to AlCl is f<2×10-9. These values differ substantially from those in IRC +10216, where AlCl has an abundance near 10-7. The NaCl observations additionally indicate a chlorine isotope ratio of 35Cl/37Cl=2.1+/-0.8 in CRL 2688, suggestive of s-process enhancement of chlorine 37.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Franklin, C.C.

The effects of insulin on glucose transport and metabolism were examined in cultured HT29 human colonic adenocarcinoma cells. The presence of glucose transporters was verified by D-glucose displaceable ({sup 3}H) cytochalasin B binding. Moreover, two classes of insulin binding sites were detected in radioligand binding experiments. Despite the presence of both glucose transporters and insulin receptors, insulin failed to stimulate glucose transport. However, insulin was found to activate glycolysis. These findings suggest that insulin directly influences substrate utilization through the glycolytic pathway in HT29 cells without activating the glucose transport pathway. A Na{sup +}/K{sup +}/Cl{sup {minus}} cotransport pathway was alsomore » detected in HT29 cells using {sup 86}Rb{sup +} as a K{sup +} congener. The identity of this pathway as a Na{sup +}/K{sup +}/Cl{sup {minus}} cotransporter has been deduced from the following findings: (1) {sup 86}Rb{sup +} influx was inhibited by loop diuretics, (2) {sup 86}Rb{sup +} influx ceased in the absence of any one of the transported ions, and (3) cotransport exhibited a stoichiometry approaching 1Na{sup +}:1K{sup +}:2Cl{sup {minus}}. Na{sup +}/K{sup +}/Cl{sup {minus}} cotransport was found to be exquisitely sensitive to cellular ATP and cyclic AMP levels. These results suggest that HT29 cells contain a Na{sup +}/K{sup +}/Cl{sup {minus}} cotransport pathway that can be regulated by the second messenger cyclic AMP and is highly sensitive to the metabolic state of the cell. The involvement of protein kinase C in the regulation of Na{sup +}/K{sup +}/Cl{sup {minus}} cotransport was also investigated. Phorbol 12-myristate 13-acetate (PMA), which stimulated protein kinase C activity, produced a transient increase in cotransport followed by a near abolition of cotransport by 2 h.« less

Grapevine and Arabidopsis Cation-Chloride Cotransporters Localize to the Golgi and Trans-Golgi Network and Indirectly Influence Long-Distance Ion Transport and Plant Salt Tolerance1[OPEN

PubMed Central

Henderson, Sam W.; Wege, Stefanie; Qiu, Jiaen; Blackmore, Deidre H.; Walker, Amanda R.; Tyerman, Stephen D.; Walker, Rob R.; Gilliham, Matthew

2015-01-01

Plant cation-chloride cotransporters (CCCs) have been implicated in conferring salt tolerance. They are predicted to improve shoot salt exclusion by directly catalyzing the retrieval of sodium (Na+) and chloride (Cl−) ions from the root xylem. We investigated whether grapevine (Vitis vinifera [Vvi]) CCC has a role in salt tolerance by cloning and functionally characterizing the gene from the cultivar Cabernet Sauvignon. Amino acid sequence analysis revealed that VviCCC shares a high degree of similarity with other plant CCCs. A VviCCC-yellow fluorescent protein translational fusion protein localized to the Golgi and the trans-Golgi network and not the plasma membrane when expressed transiently in tobacco (Nicotiana benthamiana) leaves and Arabidopsis (Arabidopsis thaliana) mesophyll protoplasts. AtCCC-green fluorescent protein from Arabidopsis also localized to the Golgi and the trans-Golgi network. In Xenopus laevis oocytes, VviCCC targeted to the plasma membrane, where it catalyzed bumetanide-sensitive 36Cl–, 22Na+, and 86Rb+ uptake, suggesting that VviCCC (like AtCCC) belongs to the Na+-K+-2Cl– cotransporter class of CCCs. Expression of VviCCC in an Arabidopsis ccc knockout mutant abolished the mutant’s stunted growth phenotypes and reduced shoot Cl– and Na+ content to wild-type levels after growing plants in 50 mm NaCl. In grapevine roots, VviCCC transcript abundance was not regulated by Cl– treatment and was present at similar levels in both the root stele and cortex of three Vitis spp. genotypes that exhibit differential shoot salt exclusion. Our findings indicate that CCC function is conserved between grapevine and Arabidopsis, but neither protein is likely to directly mediate ion transfer with the xylem or have a direct role in salt tolerance. PMID:26378102

Na+/K+/2Cl- cotransporter and CFTR gill expression after seawater transfer in smolts (0+) of different Atlantic salmon (Salmo salar) families

USGS Publications Warehouse

Mackie, P.M.; Gharbi, K.; Ballantyne, J.S.; McCormick, S.D.; Wright, P.A.

2007-01-01

Smoltification involves morphological and physiological changes in the gills that prepare anadromous salmonids to osmoregulate efficiently in seawater. In a previous study, we found that different families of Atlantic salmon (Salmo salar) smolts vary in their ability to osmoregulate when abruptly transferred to cold seawater and that these differences are correlated with gill Na+/K+ ATPase activity. Here we extend these findings to test whether other key transport proteins, namely Na+/K+/2Cl- contransporter (NKCC) and the Cl- channel or cystic fibrosis transmembrane conductance regulator (CFTR), play a significant role in osmoregulatory differences between families. To facilitate molecular analysis of NKCC, we first isolated a gill cDNA containing the complete coding region (1147 aa) of an isoform previously reported as a partial sequence. Phylogenetic analysis showed that this isoform is most closely related to isoforms of the NKCC1a subfamily found in European eel and Mozambique tilapia. In a second step, we quantified NKCC protein abundance as well as mRNA expression levels for NKCC1a and two CFTR isoforms (CFTRI and CFTRII) in 0+ smolts from three families prior to and following seawater transfer. The family with the lowest salinity tolerance also showed significant increases in gill NKCC1a mRNA after seawater transfer. Taken together with our previous study, these data indicate that family differences in expression of transport proteins are in part related to salinity tolerance, although the best indicator of osmoregulatory performance between families may be gill Na+/K+ ATPase activity and CFTR I mRNA levels, rather than Na+/K+ ATPase and NKCC1a mRNA levels or NKCC protein abundance. ?? 2007 Elsevier B.V. All rights reserved.

Effect of NaCl treatments on glucosinolate metabolism in broccoli sprouts*

PubMed Central

Guo, Rong-fang; Yuan, Gao-feng; Wang, Qiao-mei

2013-01-01

To understand the regulation mechanism of NaCl on glucosinolate metabolism in broccoli sprouts, the germination rate, fresh weight, contents of glucosinolates and sulforaphane, as well as myrosinase activity of broccoli sprouts germinated under 0, 20, 40, 60, 80, and 100 mmol/L of NaCl were investigated in our experiment. The results showed that glucoerucin, glucobrassicin, and 4-hydroxy glucobrassicin in 7-d-old broccoli sprouts were significantly enhanced and the activity of myrosinase was inhibited by 100 mmol/L of NaCl. However, the total glucosinolate content in 7-d-old broccoli sprouts was markedly decreased although the fresh weight was significantly increased after treatment with NaCl at relatively low concentrations (20, 40, and 60 mmol/L). NaCl treatment at the concentration of 60 mmol/L for 5 d maintained higher biomass and comparatively higher content of glucosinolates in sprouts of broccoli with decreased myrosinase activity. A relatively high level of NaCl treatment (100 mmol/L) significantly increased the content of sulforaphane in 7-d-old broccoli sprouts compared with the control. These results indicate that broccoli sprouts grown under a suitable concentration of NaCl could be desirable for human nutrition. PMID:23365011

Characterization and identification of Na-Cl sources in ground water

USGS Publications Warehouse

Panno, S.V.; Hackley, Keith C.; Hwang, H.-H.; Greenberg, S.E.; Krapac, I.G.; Landsberger, S.; O'Kelly, D. J.

2006-01-01

Elevated concentrations of sodium (Na+) and chloride (Cl -) in surface and ground water are common in the United States and other countries, and can serve as indicators of, or may constitute, a water quality problem. We have characterized the most prevalent natural and anthropogenic sources of Na+ and Cl- in ground water, primarily in Illinois, and explored techniques that could be used to identify their source. We considered seven potential sources that included agricultural chemicals, septic effluent, animal waste, municipal landfill leachate, sea water, basin brines, and road deicers. The halides Cl-, bromide (Br-), and iodide (I-) were useful indicators of the sources of Na+-Cl- contamination. Iodide enrichment (relative to Cl-) was greatest in precipitation, followed by uncontaminated soil water and ground water, and landfill leachate. The mass ratios of the halides among themselves, with total nitrogen (N), and with Na+ provided diagnostic methods for graphically distinguishing among sources of Na+ and Cl- in contaminated water. Cl/Br ratios relative to Cl- revealed a clear, although overlapping, separation of sample groups. Samples of landfill leachate and ground water known to be contaminated by leachate were enriched in I- and Br-; this provided an excellent fingerprint for identifying leachate contamination. In addition, total N, when plotted against Cl/Br ratios, successfully separated water contaminated by road salt from water contaminated by other sources. Copyright ?? 2005 National Ground Water Association.

Compensatory role of the NBCn1 sodium/bicarbonate cotransporter on Ca2+-induced mitochondrial swelling in hypertrophic hearts.

PubMed

Vargas, Lorena A; Velasquez, Fernanda Carrizo; Alvarez, Bernardo V

2017-03-01

NBC Na + /HCO 3 - cotransporter (NBCn1) and NHE1 Na + /H + exchanger have been associated with cardiac disorders and recently located in coronary endothelial cells (CEC) and cardiomyocytes mitochondria, respectively. Mitochondrial NHE1 blockade delays permeability transition pore (MPTP) opening and reduces superoxide levels, two critical events exacerbated in cells of diseased hearts. Conversely, activation of NBCn1 prevented apoptosis in CEC subjected to ischemic stress. We characterized the role of the NHE1 and NBCn1 transporters in heart mitochondria from hypertrophic (SHR) and control (Wistar) rats. Expression of NHE1 was analyzed in left ventricular mitochondrial lysates (LVML), by immunoblots. NHE1 expression increased by ~40% in SHR compared to control (P < 0.05, n = 4). To examine NHE1-mediated Na + /H + exchange activity in cardiac hypertrophy, mitochondria were loaded with BCECF-AM dye and the maximal rate of pHm change measured after the addition of 50 mM NaCl. SHR mitochondria had greater changes in pHm compared to Wistar, 0.10 ± 0.01 vs. 0.06 ± 0.01, respectively (P < 0.05, n = 5). In addition, mitochondrial suspensions from SHR and control myocardium were exposed to 200 μM CaCl 2 to induce MPTP opening (light-scattering decrease, LSD) and swelling. Surprisingly, SHR rats showed smaller LSD and a reduction in mitochondrial swelling, 67 ± 10% (n = 15), compared to control, 100 ± 8% (n = 13). NBC inhibition with S0859 (1 μM) significantly increased swelling in both control 139 ± 10% (n = 8) and SHR 115 ± 10% (n = 4). Finally, NBCn1 Na + /HCO 3 - cotransporter increased by twofold its expression in SHR LVML, compared to normal (P < 0.05, n = 5). We conclude that increased NBCn1 activity may play a compensatory role in hypertrophic hearts, protecting mitochondria from Ca 2+ -induced MPTP opening and swelling.

Na-glutamine co-transporters B(0)AT1 in villus and SN2 in crypts are differentially altered in chronically inflamed rabbit intestine.

PubMed

Saha, Prosenjit; Arthur, Subha; Kekuda, Ramesh; Sundaram, Uma

2012-03-01

Glutamine is a major nutrient utilized by the intestinal epithelium and is primarily assimilated via Na-glutamine co-transport (NGcT) on the brush border membrane (BBM) of enterocytes. Recently we reported that B(0)AT1 (SLC6A19) mediates glutamine absorption in villus while SN2 (SLC38A5) does the same in crypt cells. However, how B(0)AT1 and SN2 are affected during intestinal inflammation is unknown. In the present study it was shown that during chronic enteritis NGcT was inhibited in villus cells, however, it was stimulated in crypt cells. Our studies also demonstrated that the mechanism of inhibition of NGcT during chronic enteritis was secondary to a reduction in the number of B(0)AT1 co-transporters in the villus cell BBM without a change in the affinity of the co-transporter. In contrast, stimulation of NGcT in crypt cells was secondary to an increase in the affinity of SN2 for glutamine without an alteration in the number of co-transporters. Thus, glutamine assimilation which occurs via distinct transporters in crypt and villus cells is altered in the chronically inflamed intestine. Copyright © 2011 Elsevier B.V. All rights reserved.

Human SLC4A11 Is a Novel NH3/H+ Co-transporter*

PubMed Central

Zhang, Wenlin; Ogando, Diego G.; Bonanno, Joseph A.; Obukhov, Alexander G.

2015-01-01

SLC4A11 has been proposed to be an electrogenic membrane transporter, permeable to Na+, H+ (OH−), bicarbonate, borate, and NH4+. Recent studies indicate, however, that neither bicarbonate or borate is a substrate. Here, we examined potential NH4+, Na+, and H+ contributions to electrogenic ion transport through SLC4A11 stably expressed in Na+/H+ exchanger-deficient PS120 fibroblasts. Inward currents observed during exposure to NH4Cl were determined by the [NH3]o, not [NH4+]o, and current amplitudes varied with the [H+] gradient. These currents were relatively unaffected by removal of Na+, K+, or Cl− from the bath but could be reduced by inclusion of NH4Cl in the pipette solution. Bath pH changes alone did not generate significant currents through SLC4A11, except immediately following exposure to NH4Cl. Reversal potential shifts in response to changing [NH3]o and pHo suggested an NH3/H+-coupled transport mode for SLC4A11. Proton flux through SLC4A11 in the absence of ammonia was relatively small, suggesting that ammonia transport is of more physiological relevance. Methylammonia produced currents similar to NH3 but with reduced amplitude. Estimated stoichiometry of SLC4A11 transport was 1:2 (NH3/H+). NH3-dependent currents were insensitive to 10 μm ethyl-isopropyl amiloride or 100 μm 4,4′- diisothiocyanatostilbene-2,2′-disulfonic acid. We propose that SLC4A11 is an NH3/2H+ co-transporter exhibiting unique characteristics. PMID:26018076

Effect of NaCl concentration on productivity and mineral composition of Salicornia europaea as a potential crop for utilization NaCl in LSS

NASA Astrophysics Data System (ADS)

Ushakova, S. A.; Kovaleva, N. P.; Gribovskaya, I. V.; Dolgushev, V. A.; Tikhomirova, N. A.

The accumulation of solid and liquid wastes in manmade ecosystems presents a problem that has not been efficiently solved yet. Urine, containing NaCl, are part of these products. This is an obstacle to the creation of biological systems with a largely closed material cycling, because the amount of solid and liquid wastes in them must be reduced to a minimum. A possible solution to the problem is to select plant species capable of utilizing sufficiently high concentrations of NaCl, edible for humans, and featuring high productivity. Until recently, the life support systems have included the higher plants that were either sensitive to salinization (wheat, many of the legumes, carrot, potato, maize) or relatively salt-resistant (barley, sugar beet, spinach). Salicomia europaea, whose above-ground part is fully edible for humans, is one of the most promising candidates to be included in life support systems. It is reported in the literature that this plant is capable of accumulating up to 50% NaCl (dry basis). Besides, excessive accumulation of sodium ions should bring forth a decrease in the uptake of potassium ions and other biogenic elements. The aim of this work is to study the feasibility of using S. europaea plants in growth chambers to involve NaCl into material cycling. Plants were grown in vegetation chambers at the irradiance of 100 or 150 W/m 2 PAR (photosynthetically active radiation) and the air temperature 24 °C, by two methods. The first method was to grow the plants on substrate - peat. The peat was supplemented with either 3% NaCl (Variant 1) or 6% NaCl (Variant 2) of the oven-dry mass of the peat. The second method was to grow the plants in water culture, using the solution with a full complement of nutrients, which contained 0.0005% of NaCl, 1% or 2%. The study showed that the addition of NaCl to the substrate or to the solution resulted in the formation of more succulent plants, which considerably increased their biomass. The amount of NaCl uptake

Optically stimulated luminescence in doped NaCl

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gaikwad, S. U., E-mail: gaikwadsonali09@yahoo.com; Patil, R. R.; Kulkarni, M. S.

NaCl:Ca,Cu,P NaCl:Mg,Cu,P OSL phosphors are synthesized. Intense OSL is observed in these samples which is 14 times more than Al{sub 2}O{sub 3}:C. Same samples coated with PVA (poly vinyl actetae) polymer also show similar OSL properties and these coated samples are found to be less susceptible to the moisture due to protected layer of hydrophobic polymer. These coated samples may be useful as OSL dosimetersdue to high sensitivity and less or no susceptibility to moisture.

Apical Na(+)-D-glucose cotransporter 1 (SGLT1) activity and protein abundance are expressed along the jejunal crypt-villus axis in the neonatal pig

USDA-ARS?s Scientific Manuscript database

Gut apical Na(+)-glucose cotransporter 1 (SGLT1) activity is high at the birth and during suckling, thus contributing substantially to neonatal glucose homeostasis. We hypothesize that neonates possess high SGLT1 maximal activity by expressing apical SGLT1 protein along the intestinal crypt-villus a...

Na+-glucose cotransporter SGLT1 protein in salivary glands: potential involvement in the diabetes-induced decrease in salivary flow.

PubMed

Sabino-Silva, R; Freitas, H S; Lamers, M L; Okamoto, M M; Santos, M F; Machado, U F

2009-03-01

Oral health complications in diabetes include decreased salivary secretion. The SLC5A1 gene encodes the Na(+)-glucose cotransporter SGLT1 protein, which not only transports glucose, but also acts as a water channel. Since SLC5A1 expression is altered in kidneys of diabetic subjects, we hypothesize that it could also be altered in salivary glands, contributing to diabetic dysfunction. The present study shows a diabetes-induced decrease (p < 0.001) in salivary secretion, which was accompanied by enhanced (p < 0.05) SGLT1 mRNA expression in parotid (50%) and submandibular (30%) glands. Immunohistochemical analysis of parotid gland of diabetic rats revealed that SGLT1 protein expression increased in the luminal membrane of ductal cells, which can stimulate water reabsorption from primary saliva. Furthermore, SGLT1 protein was reduced in myoepithelial cells of the parotid from diabetic animals, and that, by reducing cellular contractile activity, might also be related to reduced salivary flux. Six-day insulin-treated diabetic rats reversed all alterations. In conclusion, diabetes increases SLC5A1 gene expression in salivary glands, increasing the SGLT1 protein content in the luminal membrane of ductal cells, which, by increasing water reabsorption, might explain the diabetes-induced decrease in salivary secretion.

NMR studies on Na+ transport in Synechococcus PCC 6311

NASA Technical Reports Server (NTRS)

Nitschmann, W. H.; Packer, L.

1992-01-01

The freshwater cyanobacterium Synechococcus PCC 6311 is able to adapt to grow after sudden exposure to salt (NaCl) stress. We have investigated the mechanism of Na+ transport in these cells during adaptation to high salinity. Na+ influx under dark aerobic conditions occurred independently of delta pH or delta psi across the cytoplasmic membrane, ATPase activity, and respiratory electron transport. These findings are consistent with the existence of Na+/monovalent anion cotransport or simultaneous Na+/H+ +anion/OH- exchange. Na+ influx was dependent on Cl-, Br-, NO3-, or NO2-. No Na+ uptake occurred after addition of NaI, NaHCO3, or Na2SO4. Na+ extrusion was absolutely dependent on delta pH and on an ATPase activity and/or on respiratory electron transport. This indicates that Na+ extrusion via Na+/H+ exchange is driven by primary H+ pumps in the cytoplasmic membrane. Cells grown for 4 days in 0.5 m NaCl medium, "salt-grown cells," differ from control cells by a lower maximum velocity of Na+ influx and by lower steady-state ratios of [Na+]in/[Na+]out. These results indicate that cells grown in high-salt medium increase their capacity to extrude Na+. During salt adaptation Na+ extrusion driven by respiratory electron transport increased from about 15 to 50%.

Ecotoxicological evaluation of three deicers (NaCl, NaFo, CMA)-effect on terrestrial organisms.

PubMed

Robidoux, P Y; Delisle, C E

2001-02-01

The use of chemical deicers such as sodium chloride (NaCl) has increased significantly during the past three decades. Deicers induce metal corrosion and alter the physicochemical properties of soils and water. Environmental damage caused by the use of NaCl has prompted government agencies to find alternative deicers. This article presents a comparative ecotoxicological study of three deicers on soil organisms. Sodium formiate (NaFo) and calcium-magnesium acetate (CMA) are the most interesting commercially available deicers based upon their characteristics and potential toxicity. Organisms used in this study were four species of macrophytes (cress (Lepidium sativum), barley (Ordeum vulgare), red fescue grass (Festuca rubra), Kentucky bluegrass (Poa pratensis)) and an invertebrate (Eisenia fetida). Using standardized and modified methods, the relative toxicity of deicers was CMA < NaFo congruent with NaCl. The results demonstrate that these chemicals could have similar impacts in terrestrial environments since similar quantities of NaFo and greater amounts of CMA are necessary to achieve the same efficiency as NaCl. The toxicity of the tested substances was lower in natural composted soil than in artificial substrate (silica or OECD soil), indicating decreased environmental bioavailability. The response of the organisms changed according to endpoint, species, and soil characteristics (artificial substrate as compared to natural organic soil). The most sensitive endpoint measured was macrophyte growth with Kentucky bluegrass being the most sensitive species. Copyright 2001 Academic Press.

Solubility of NaCl in aqueous electrolyte solutions from 10 to 100°C

USGS Publications Warehouse

Clynne, M.A.; Potter, R.W.; Haas, J.L.

1981-01-01

The solubilities of NaCl in aqueous KCl, MgCl2, CaCl2, and mixed CaCl2-KCl solutions have been determined from 10 to 100??C. The data were fit to an equation, and the equation was used to calculate values of the change in solubility of NaCl, ???[NaCl]/???T. These values are required for calculations of the rate of migration of fluids in a thermal gradient in rock salt. The data obtained here indicate that the values of ???[NaCl]/???T are 36-73% greater for solutions containing divalent ions than for the NaCl-H2O system.

Water-Soluble Epitaxial NaCl Thin Film for Fabrication of Flexible Devices.

PubMed

Lee, Dong Kyu; Kim, Sungjoo; Oh, Sein; Choi, Jae-Young; Lee, Jong-Lam; Yu, Hak Ki

2017-08-18

We studied growth mechanisms of water-soluble NaCl thin films on single crystal substrates. Epitaxial growth of NaCl(100) on Si(100) and domain-matched growth of NaCl(111) on c-sapphire were obtained at thicknesses below 100 nm even at room temperature from low lattice mismatches in both cases. NaCl thin film, which demonstrates high solubility selectivity for water, was successfully applied as a water-soluble sacrificial layer for fabrication of several functional materials, such as WO 3 nano-helix and Sn doped In 2 O 3 nano-branches.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johanson, C.E.; Sweeney, S.M.; Parmelee, J.T.

Cerebrospinal fluid formation stems primarily from the transport of Na and Cl in choroid plexus (CP). To characterize properties and modulation of choroidal transporters, we tested diuretics and other agents for ability to alter ion transport in vitro. Adult Sprague-Dawley rats were the source of CPs preincubated with drug for 20 min and then transferred to cerebrospinal fluid (CSF) medium containing 22Na or 36Cl with (3H)mannitol (extracellular correction). Complete base-line curves were established for cellular uptake of Na and Cl at 37 degrees C. The half-maximal uptake occurred at 12 s, so it was used to assess drug effects onmore » rate of transport (nmol Na or Cl/mg CP). Bumetanide (10(-5) and 10(-4) M) decreased uptake of Na and Cl with maximal inhibition (up to 45%) at 10(-5) M. Another cotransport inhibitor, furosemide (10(-4) M), reduced transport of Na by 25% and Cl by 33%. However, acetazolamide (10(-4) M) and atriopeptin III (10(-7) M) significantly lowered uptake of Na (but not Cl), suggesting effect(s) other than on cotransport. The disulfonic stilbene 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS; 10(-4) M), known to inhibit Cl-HCO3 exchange, substantially reduced the transport of 36Cl. Bumetanide plus DIDS (both 10(-4) M) caused additive inhibition of 90% of Cl uptake, which provides strong evidence for the existence of both cotransport and antiport Cl carriers. Overall, this in vitro analysis, uncomplicated by variables of blood flow and neural tone, indicates the presence in rat CP of the cotransport of Na and Cl in addition to the established Na-H and Cl-HCO3 exchangers.« less

NaCl and water responses across the frog tongue epithelium in vitro.

PubMed

Soeda, H; Sakudo, F

1990-01-01

Isolated dorsal epithelium of the frog tongue elicited transepithelial NaCl and water responses across the tissue when NaCl was added to or removed from the adapting Ringer solution in the mucosal surface, respectively. The NaCl response which was a negative polarization in the mucosa with respect to the serosa was associated with a decrease in resistance across the tissue, whereas the water response which was a positive polarization was associated with an increase in the resistance. The decrease and increase in the tissue resistance remained unchanged by various polarizations of the transepithelial potential difference across the tissue. Characteristics of the NaCl and water responses were similar in many respects to those in the taste cells and nerves of frogs. Thus the NaCl and water responses may relate to taste reception.

A Sensor Based on LiCl/NaA Zeolite Composites for Effective Humidity Sensing.

PubMed

Zhang, Ying; Xiang, Hongyu; Sun, Liang; Xie, Qiuhong; Liu, Man; Chen, Yu; Ruan, Shengping

2018-03-01

LiCl/NaA zeolite composites were successfully prepared by doping 1 wt%, 2 wt%, 5 wt%, and 8 wt% of LiCl into NaA zeolite. The humidity sensing properties of LiCl/NaA composites were investigated among 11% 95% relative humidity (RH). The LiCl/NaA composites exhibited better humidity sensing properties than pure NaA zeolite. The sensor made by 2 wt% Li-doped NaA zeolite possesses the best linearly in the whole RH. These results demonstrate that the LiCl/NaA composites have the potential application in humidity sensing.

Energetics of acclimation to NaCl by submerged, anoxic rice seedlings

PubMed Central

Kurniasih, Budiastuti; Greenway, Hank; Colmer, Timothy David

2017-01-01

Background and aims Our aim was to elucidate how plant tissues under a severe energy crisis cope with imposition of high NaCl, which greatly increases ion fluxes and hence energy demands. The energy requirements for ion regulation during combined salinity and anoxia were assessed to gain insights into ion transport processes in the anoxia-tolerant coleoptile of rice. Methods We studied the combined effects of anoxia plus 50 or 100 mm NaCl on tissue ions and growth of submerged rice (Oryza sativa) seedlings. Excised coleoptiles allowed measurements in aerated or anoxic conditions of ion net fluxes and O2 consumption or ethanol formation and by inference energy production. Key Results Over 80 h of anoxia, coleoptiles of submerged intact seedlings grew at 100 mm NaCl, but excised coleoptiles, with 50 mm exogenous glucose, survived only at 50 mm NaCl, possibly due to lower energy production with glucose than for intact coleoptiles with sucrose as substrate. Rates of net uptake of Na+ and Cl− by coleoptiles in anoxia were about half those in aerated solution. Ethanol formation in anoxia and O2 uptake in aerobic solution were each increased by 13–15 % at 50 mm NaCl, i.e. ATP formation was stimulated. For acclimation to 50 mm NaCl, the anoxic tissues used only 25 % of the energy that was expended by aerobic tissues. Following return of coleoptiles to aerated non-saline solution, rates of net K+ uptake recovered to those in continuously aerated solution, demonstrating there was little injury during anoxia with 50 mm NaCl. Conclusion Rice seedlings survive anoxia, without the coleoptile incurring significant injury, even with the additional energy demands imposed by NaCl (100 mm when intact, 50 mm when excised). Energy savings were achieved in saline anoxia by less coleoptile growth, reduced ion fluxes as compared to aerobic coleoptiles and apparent energy-economic ion transport systems. PMID:27694332

The Na+-phosphate cotransport system (NaPi-II) with a cleaved protein backbone: implications on function and membrane insertion

PubMed Central

Kohl, Beate; Wagner, Carsten A; Huelseweh, Birgit; Busch, Andreas E; Werner, Andreas

1998-01-01

Renal handling of inorganic phosphate (Pi) involves a Na+-Pi cotransport system which is well conserved between vertebrates. The members of this protein family, denoted NaPi-II, share a topology with, it is thought, eight transmembrane domains. The transporter is proposed to be proteolytically cleaved within a large hydrophilic loop in vivo. The consequences of an interrupted backbone were tested by constructing cDNA clones encoding different N- (1-3 and 1-5) and C-terminal (4-8 and 6-8) complementary fragments of NaPi-II from winter flounder. When the cognate fragments were used in combination (1-3 plus 4-8; 1-5 plus 6-8) they comprised the full complement of the putative transporter domains. None of the four individual fragments or the 1-5 plus 6-8 combination when expressed in Xenopus oocytes increased Pi flux. Coexpression of fragments 1-3 plus 4-8 stimulated transport activity identical to that for expressed wild-type NaPi-II with regard to pH dependency and Km for Na+ and Pi binding; however, the maximal transport rate (vmax) was lower. Immunohistochemistry on cryosections confined the functionally active 1-3 plus 4-8 combination to the oocyte membrane. This was not the case for the 1-5 plus 6-8 combination or any of the individual fragments, all of which failed to induce fluorescence. A second immunohistochemical approach using intact oocytes allowed determination of the extracellular regions of the protein. Epitopes within the loop between transmembrane domains 3 and 4 enhanced fluorescence. Neither N- nor C-terminal tags induced fluorescence. PMID:9508800

A noninvasive optical approach for assessing chloride extrusion activity of the K-Cl cotransporter KCC2 in neuronal cells.

PubMed

Ludwig, Anastasia; Rivera, Claudio; Uvarov, Pavel

2017-01-31

Cation-chloride cotransporters (CCCs) are indispensable for maintaining chloride homeostasis in multiple cell types, but K-Cl cotransporter KCC2 is the only CCC member with an exclusively neuronal expression in mammals. KCC2 is critical for rendering fast hyperpolarizing responses of ionotropic γ-aminobutyric acid and glycine receptors in adult neurons, for neuronal migration in the developing central nervous system, and for the formation and maintenance of small dendritic protrusions-dendritic spines. Deficit in KCC2 expression and/or activity is associated with epilepsy and neuropathic pain, and effective strategies are required to search for novel drugs augmenting KCC2 function. We revised current methods to develop a noninvasive optical approach for assessing KCC2 transport activity using a previously characterized genetically encoded chloride sensor. Our protocol directly assesses dynamics of KCC2-mediated chloride efflux and allows measuring genuine KCC2 activity with good spatial and temporal resolution. As a proof of concept, we used this approach to compare transport activities of the two known KCC2 splice isoforms, KCC2a and KCC2b, in mouse neuronal Neuro-2a cells. Our noninvasive optical protocol proved to be efficient for assessment of furosemide-sensitive chloride fluxes. Transport activities of the N-terminal splice isoforms KCC2a and KCC2b obtained by the novel approach matched to those reported previously using standard methods for measuring chloride fluxes.

Light Moderates the Induction of Phosphoenolpyruvate Carboxylase by NaCl and Abscisic Acid in Mesembryanthemum crystallinum 1

PubMed Central

McElwain, Elizabeth F.; Bohnert, Hans J.; Thomas, John C.

1992-01-01

In Mesembryanthemum crystallinum, phosphoenolpyruvate carboxylase is synthesized de novo in response to osmotic stress, as part of the switch from C3-photosynthesis to Crassulacean acid metabolism. To better understand the environmental signals involved in this pathway, we have investigated the effects of light on the induced expression of phosphoenolpyruvate carboxylase mRNA and protein in response to stress by 400 millimolar NaCl or 10 micromolar abscisic acid in hydroponically grown plants. When plants were grown in high-intensity fluorescent or incandescent light (850 microeinsteins per square meter per second), NaCl and abscisic acid induced approximately an eightfold accumulation of phosphoenolpyruvate carboxylase mRNA when compared to untreated controls. Levels of phosphoenolpyruvate carboxylase protein were high in these abscisic acid- and NaCl-treated plants, and detectable in the unstressed control. Growth in high-intensity incandescent (red) light resulted in approximately twofold higher levels of phosphoenolpyruvate carboxylase mRNA in the untreated plants when compared to control plants grown in high-intensity fluorescent light. In low light (300 microeinsteins per square meter per second fluorescent), only NaCl induced mRNA levels significantly above the untreated controls. Low light grown abscisic acid- and NaCl-treated plants contained a small amount of phosphoenolpyruvate carboxylase protein, whereas the (untreated) control plants did not contain detectable amounts of phosphoenolpyruvate carboxylase. Environmental stimuli, such as light and osmotic stress, exert a combined effect on gene expression in this facultative halophyte. ImagesFigure 1Figure 2 PMID:16668999

The structure of PbCl2 on the {100} surface of NaCl and its consequences for crystal growth

NASA Astrophysics Data System (ADS)

Townsend, Eleanor R.; Brugman, Sander J. T.; Blijlevens, Melian A. R.; Smets, Mireille M. H.; de Poel, Wester; van Enckevort, Willem J. P.; Meijer, Jan A. M.; Vlieg, Elias

2018-04-01

The role that additives play in the growth of sodium chloride is a topic which has been widely researched but not always fully understood at an atomic level. Lead chloride (PbCl2) is one such additive which has been reported to have growth inhibition effects on NaCl {100} and {111}; however, no definitive evidence has been reported which details the mechanism of this interaction. In this investigation, we used the technique of surface x-ray diffraction to determine the interaction between PbCl2 and NaCl {100} and the structure at the surface. We find that Pb2+ replaces a surface Na+ ion, while a Cl- ion is located on top of the Pb2+. This leads to a charge mismatch in the bulk crystal, which, as energetically unfavourable, leads to a growth blocking effect. While this is a similar mechanism as in the anticaking agent ferrocyanide, the effect of PbCl2 is much weaker, most likely due to the fact that the Pb2+ ion can more easily desorb. Moreover, PbCl2 has an even stronger effect on NaCl {111}.

Role of an extracellular loop in determining the stoichiometry of Na+–HCO3− cotransporters

PubMed Central

Chen, Li-Ming; Liu, Ying; Boron, Walter F

2011-01-01

The Na+–HCO3− cotransporters (NBCs) of the solute carrier 4 family (SLC4) are critical for regulating pH in cells as well as in fluids such as blood and cerebrospinal fluid. Moreover, mutations and gene disruptions in NBC are linked to a wide range of pathologies. NBCe1 (SLC4A4) is electrogenic because it has an apparent Na+:HCO3− stoichiometry of 1:2 or 1:3, whereas NBCn1 (SLC4A7) is electroneutral because it has an apparent stoichiometry of 1:1. Because stoichiometry influences the effect of transport on membrane potential and vice versa, a central question is what structural features underlie electrogenicity versus electroneutrality. A previous study on rat NBCe1/n1 chimeras demonstrated that the structural elements determining the electrogenicity of NBCe1-A are located within the transmembrane domain, excluding the large third extracellular loop. In the present study we generated a series of chimeras of human NBCe1-A and human NBCn1-A. We found that replacing merely the predicted fourth extracellular loop (EL4) – containing 32 amino acid residues that include 7 prolines – of human NBCe1-A with EL4 of NBCn1-A creates an electroneutral NBC. The opposite switch converts an electroneutral construct to one with electrogenic properties. The introduction of an N-glycosylation site into EL4 confirms that at least a part of it is exposed to the extracellular fluid. We hypothesize that putative EL4 either contributes to the substrate-binding vestibule or indirectly influences substrate binding by interacting with one or more transmembrane segments, thereby controlling the nature of transport. PMID:21224233

NaCl-triggered self-assembly of hydrophilic poloxamine block copolymers.

PubMed

Bahadur, Anita; Cabana-Montenegro, Sonia; Aswal, Vinod Kumar; Lage, Emilio V; Sandez-Macho, Isabel; Concheiro, Angel; Alvarez-Lorenzo, Carmen; Bahadur, Pratap

2015-10-15

Tetronic 1307 (T1307) is a hydrophilic poloxamine (HLB>24) with a high molecular mass owing to its long PEO and PPO blocks. In spite of good biocompatibility, its use as a component of drug delivery systems is limited by its high critical micelle concentration (CMC) and temperature (CMT). The aim of this work was to elucidate whether the addition of NaCl or the combination of salts and temperature may bring T1307 micellization and gelling features into more practically useful values. Increasing NaCl concentration in the 0.154 M (isotonic) to 2M (hypertonic) range made the copolymer more hydrophobic and more prone to self-assemble into unimodal micelles, as observed by means of π-A isotherms, (1)H NMR, dynamic light scattering (DLS), small-angle neutron scattering (SANS), and pyrene fluorescence. The decrease in CMC and CMT observed for T1307 in 0.5 M NaCl medium (tolerable hypertonic solution), compared to water, notably favored the solubility of hydrophobic drugs such as curcumin and quercetin. Moreover, phase diagram, intrinsic viscosity and sol-to-gel transition were markedly affected by NaCl concentration. Overall, the strong dependence of T1307 self-assembly features on NaCl opens interesting possibilities for tuning the performance of T1307 as a component of nanocarriers and in situ gelling systems. Copyright © 2015 Elsevier B.V. All rights reserved.

Enteropathogenic E. coli attenuates secretagogue-induced net intestinal ion transport but not Cl- secretion.

PubMed

Hecht, G; Koutsouris, A

1999-03-01

Enteric bacterial pathogens often increase intestinal Cl- secretion. Enteropathogenic Escherichia coli (EPEC) does not stimulate active ion secretion. In fact, EPEC infection decreases net ion transport in response to classic secretagogues. This has been presumed to reflect diminished Cl- secretion. The aim of this study was to investigate the influence of EPEC infection on specific intestinal epithelial ion transport processes. T84 cell monolayers infected with EPEC were used for these studies. EPEC infection significantly decreased short-circuit current (Isc) in response to carbachol and forskolin, yet 125I efflux studies revealed no difference in Cl- channel activity. There was also no alteration in basolateral K+ channel or Na+-K+-2Cl- cotransport activity. Furthermore, net 36Cl- flux was not decreased by EPEC. No alterations in either K+ or Na+ transport could be demonstrated. Instead, removal of basolateral bicarbonate from uninfected monolayers yielded an Isc response approximating that observed with EPEC infection, whereas bicarbonate removal from EPEC-infected monolayers further diminished Isc. These studies suggest that the reduction in stimulated Isc is not secondary to diminished Cl- secretion. Alternatively, bicarbonate-dependent transport processes appear to be perturbed.

The ground state of metallic nano-structures in heavily irradiated NaCl-KBF4

NASA Astrophysics Data System (ADS)

Cherkasov, F. G.; L'Vov, S. G.; Tikhonov, D. A.; den Hartog, H. W.; Vainshtein, D. I.

ESR, NMR and static magnetic susceptibility measurements of heavily irradiated NaCl-K and NaCl-KBF4 are reported. Up to 10% of the NaCl-molecules are transformed into metallic Na nanoparticles and Cl-2 precipitates. In addition, there are paramagnetic F- and F-aggregates, which are coupled by exchange interactions to the conduction electrons in the nanoparticles. Above 160 K the NMR and ESR signals of NaCl-K and NaCl-KBF4 show Pauli paramagnetism and the properties of the Na nanoparticles are similar to bulk sodium. A single ESR line is observed revealing exchange interaction between conduction electrons in the nano-particles and F-aggregates. The observed decrease of the ESR susceptibility with decreasing temperature is due to a metal-insulator transition. The conduction electrons are localized below 40 K and the above mentioned F-aggregate centers contribute significantly to the overall ESR signal. For NaCl-KBF4 we observed that with decreasing temperature the ESR line shifts towards lower fields due to antiferromagnetic ordering and internal magnetic fields.

The alteration of mRNA expression of SOD and GPX genes, and proteins in tomato (Lycopersicon esculentum Mill) under stress of NaCl and/or ZnO nanoparticles.

PubMed

Alharby, Hesham F; Metwali, Ehab M R; Fuller, Michael P; Aldhebiani, Amal Y

2016-11-01

Five cultivars of tomato having different levels of salt stress tolerance were exposed to different treatments of NaCl (0, 3 and 6 g L -1 ) and ZnO-NPs (0, 15 and 30 mg L -1 ). Treatments with NaCl at both 3 and 6 g L -1 suppressed the mRNA levels of superoxide dismutase (SOD) and glutathione peroxidase (GPX) genes in all cultivars while plants treated with ZnO-NPs in the presence of NaCl, showed increments in the mRNA expression levels. This indicated that ZnO-NPs had a positive response on plant metabolism under salt stress. Superior expression levels of mRNA were observed in the salt tolerant cultivars, Sandpoint and Edkawy while the lowest level was detected in the salt sensitive cultivar, Anna Aasa. SDS-PAGE showed clear differences in patterns of protein expression among the cultivars. A negative protein marker for salt sensitivity and ZnO-NPs was detected in cv. Anna Aasa at a molecular weight of 19.162 kDa, while the tolerant cultivar Edkawy had two positive markers at molecular weights of 74.991 and 79.735 kDa.

The Electrochemical Co-reduction of Mg-Al-Y Alloys in the LiCl-NaCl-MgCl2-AlF3-YCl3 Melts

NASA Astrophysics Data System (ADS)

Li, Mei; Liu, Yaochen; Han, Wei; Wang, Shanshan; Zhang, Milin; Yan, Yongde; Shi, Weiqun

2015-04-01

The electrochemical formation of Mg-Al-Y alloys was studied in the LiCl-NaCl-MgCl2 melts by the addition of AlF3 and YCl3 on a molybdenum electrode at 973 K (700 °C). In order to reduce the volatilization of salt solvent in the electrolysis process, the volatile loss of LiCl-NaCl-MgCl2 and LiCl-KCl-MgCl2 melts was first measured in the temperature range from 873 K to 1023 K (600 °C to 750 °C). Then, the electrochemical behaviors of Mg(II), Al(III), Y(III) ions and alloy formation processes were investigated by cyclic voltammetry, chronopotentiometry, and open circuit chronopotentiometry. The cyclic voltammograms indicate that the under-potential deposition of magnesium and yttrium on pre-deposited Al leads to formation of Mg-Al and Al-Y intermetallic compounds. The Mg-Al-Y alloys were prepared by galvanostatic electrolysis in the LiCl-NaCl-MgCl2-AlF3-YCl3 melts and characterized by X-ray diffraction and scanning electron microscopy with energy dispersive spectrometry. Composition of the alloys was analyzed by inductively coupled plasma-atomic emission spectrometer, and current efficiency was also determined by the alloy composition.

Identification of a 3rd Na+ Binding Site of the Glycine Transporter, GlyT2.

PubMed

Subramanian, Nandhitha; Scopelitti, Amanda J; Carland, Jane E; Ryan, Renae M; O'Mara, Megan L; Vandenberg, Robert J

2016-01-01

The Na+/Cl- dependent glycine transporters GlyT1 and GlyT2 regulate synaptic glycine concentrations. Glycine transport by GlyT2 is coupled to the co-transport of three Na+ ions, whereas transport by GlyT1 is coupled to the co-transport of only two Na+ ions. These differences in ion-flux coupling determine their respective concentrating capacities and have a direct bearing on their functional roles in synaptic transmission. The crystal structures of the closely related bacterial Na+-dependent leucine transporter, LeuTAa, and the Drosophila dopamine transporter, dDAT, have allowed prediction of two Na+ binding sites in GlyT2, but the physical location of the third Na+ site in GlyT2 is unknown. A bacterial betaine transporter, BetP, has also been crystallized and shows structural similarity to LeuTAa. Although betaine transport by BetP is coupled to the co-transport of two Na+ ions, the first Na+ site is not conserved between BetP and LeuTAa, the so called Na1' site. We hypothesized that the third Na+ binding site (Na3 site) of GlyT2 corresponds to the BetP Na1' binding site. To identify the Na3 binding site of GlyT2, we performed molecular dynamics (MD) simulations. Surprisingly, a Na+ placed at the location consistent with the Na1' site of BetP spontaneously dissociated from its initial location and bound instead to a novel Na3 site. Using a combination of MD simulations of a comparative model of GlyT2 together with an analysis of the functional properties of wild type and mutant GlyTs we have identified an electrostatically favorable novel third Na+ binding site in GlyT2 formed by Trp263 and Met276 in TM3, Ala481 in TM6 and Glu648 in TM10.

Atomic-scale imaging of the dissolution of NaCl islands by water at low temperature

NASA Astrophysics Data System (ADS)

Peng, Jinbo; Guo, Jing; Ma, Runze; Meng, Xiangzhi; Jiang, Ying

2017-03-01

The dissolution of sodium chloride (NaCl) in water is a frequently encountered process in our daily lives. While the NaCl dissolution process in liquid water has been extensively studied, whether and how the dissolution occurs below the freezing point is still not clear. Using a low-temperature scanning tunneling microscope (STM), here we were able to directly visualize the dissolution of Au-supported NaCl (0 0 1) bilayer islands by water at atomic level. We found that the single water molecule on the STM tip can assist the extraction of single Na+ from the NaCl surface even at 5 K, while leaving the Cl- intact. When covered with a full water monolayer, the NaCl islands started to dissolve from the step edges and also showed evidence of dissolution inside the terraces as the temperature was raised up to 145 K. At 155 K, the water molecules completely desorbed from the surface, which was accompanied with the decomposition and restructuring of the bilayer NaCl islands. Those results suggest that the dissolution of NaCl may occur well below the freezing point at the ice/NaCl interfaces and is mainly driven by the interaction between the water molecules and the Na+, which is in clear contrast with the NaCl dissolution in liquid water.

Hsp70 and Hsp90 Multichaperone Complexes Sequentially Regulate Thiazide-sensitive Cotransporter Endoplasmic Reticulum-associated Degradation and Biogenesis*

PubMed Central

Donnelly, Bridget F.; Needham, Patrick G.; Snyder, Avin C.; Roy, Ankita; Khadem, Shaheen; Brodsky, Jeffrey L.; Subramanya, Arohan R.

2013-01-01

The thiazide-sensitive NaCl cotransporter (NCC) is the primary mediator of salt reabsorption in the distal convoluted tubule and is a key determinant of the blood pressure set point. Given its complex topology, NCC is inefficiently processed and prone to endoplasmic reticulum (ER)-associated degradation (ERAD), although the mechanisms governing this process remain obscure. Here, we identify factors that impact the ER quality control of NCC. Analyses of NCC immunoprecipitates revealed that the cotransporter formed complexes with the core chaperones Hsp90, Hsp70, and Hsp40. Disruption of Hsp90 function accelerated NCC degradation, suggesting that Hsp90 promotes NCC folding. In addition, two cochaperones, the C terminus of Hsp70-interacting protein (CHIP) and the Hsp70/Hsp90 organizer protein, were associated with NCC. Although CHIP, an E3 ubiquitin ligase, promoted NCC ubiquitination and ERAD, the Hsp70/Hsp90 organizer protein stabilized NCC turnover, indicating that these two proteins differentially remodel the core chaperone systems to favor cotransporter degradation and biogenesis, respectively. Adjusting the folding environment in mammalian cells via reduced temperature enhanced NCC biosynthetic trafficking, increased Hsp90-NCC interaction, and diminished binding to Hsp70. In contrast, cotransporters harboring disease-causing mutations that impair NCC biogenesis failed to escape ERAD as efficiently as the wild type protein when cells were incubated at a lower temperature. Instead, these mutants interacted more strongly with Hsp70, Hsp40, and CHIP, consistent with a role for the Hsp70/Hsp40 system in selecting misfolded NCC for ERAD. Collectively, these observations indicate that Hsp70 and Hsp90 comprise two functionally distinct ER quality control checkpoints that sequentially monitor NCC biogenesis. PMID:23482560

Temperature dependence of thermal pressure for NaCl

NASA Astrophysics Data System (ADS)

Singh, Chandra K.; Pande, Brijesh K.; Pandey, Anjani K.

2018-05-01

Engineering applications of the materials can be explored upto the desired limit of accuracy with the better knowledge of its mechanical and thermal properties such as ductility, brittleness and Thermal Pressure. For the resistance to fracture (K) and plastic deformation (G) the ratio K/G is treated as an indication of ductile or brittle character of solids. In the present work we have tested the condition of ductility and brittleness with the calculated values of K/G for the NaCl. It is concluded that the nature of NaCl can be predicted upto high temperature simply with the knowledge of its elastic stiffness constant only. Thermoelastic properties of materials at high temperature is directly related to thermal pressure and volume expansion of the materials. An expression for the temperature dependence of thermal pressure is formulated using basic thermodynamic identities. It is observed that thermal pressure ΔPth calculated for NaCl by using Kushwah formulation is in good agreement with the experimental values also the thermal pressure increases with the increase in temperature.

Crystallization of D-mannitol in binary mixtures with NaCl: phase diagram and polymorphism.

PubMed

Telang, Chitra; Suryanarayanan, Raj; Yu, Lian

2003-12-01

To study the crystallization, polymorphism, and phase behavior of D-mannitol in binary mixtures with NaCl to better understand their interactions in frozen aqueous solutions. Differential scanning calorimetry, hot-stage microscopy, Raman microscopy, and variable-temperature X-ray diffractometry were used to characterize D-mannitol-NaCl mixtures. NaCl and D-mannitol exhibited significant melt miscibility (up to 7.5% w/w or 0.20 mole fraction of NaCl) and a eutectic phase diagram (eutectic composition 7.5% w/w NaCl; eutectic temperature 150 degrees C for the alpha and beta polymorphs of D-mannitol and 139 degrees C for the delta). The presence of NaCl did not prevent mannitol from crystallizing but, depending on sample size, affected the polymorph crystallized: below 10 mg, delta was obtained; above 100 mg, alpha was obtained. Pure mannitol crystallized under the same conditions first as the delta polymorph and then as the a polymorph, with the latter nucleating on the former. KCl showed similar eutectic points and melt miscibility with D-mannitol as NaCl. LiCl yielded lower eutectic melting points, inhibited the crystallization of D-mannitol during cooling, and enabled the observation of its glass transition. Despite their structural dissimilarity, significant melt miscibility exists between D-mannitol and NaCl. Their phase diagram has been determined and features polymorph-dependent eutectic points. NaCl influences the polymorphic behavior of mannitol, and the effect is linked to the crystallization of mannitol in two polymorphic stages.

Amiloride-Sensitive and Amiloride-Insensitive Responses to NaCl + Acid Mixtures in Hamster Chorda Tympani Nerve

PubMed Central

Hettinger, Thomas P.; Savoy, Lawrence D.; Frank, Marion E.

2012-01-01

Component signaling in taste mixtures containing both beneficial and dangerous chemicals depends on peripheral processing. Unidirectional mixture suppression of chorda tympani (CT) nerve responses to sucrose by quinine and acid is documented for golden hamsters (Mesocricetus auratus). To investigate mixtures of NaCl and acids, we recorded multifiber responses to 50 mM NaCl, 1 and 3 mM citric acid and acetic acid, 250 μM citric acid, 20 mM acetic acid, and all binary combinations of each acid with NaCl (with and without 30 μM amiloride added). By blocking epithelial Na+ channels, amiloride treatment separated amiloride-sensitive NaCl-specific responses from amiloride-insensitive electrolyte-generalist responses, which encompass all of the CT response to the acids as well as responses to NaCl. Like CT sucrose responses, the amiloride-sensitive NaCl responses were suppressed by as much as 50% by citric acid (P = 0.001). The amiloride-insensitive electrolyte-generalist responses to NaCl + acid mixtures approximated the sum of NaCl and acid component responses. Thus, although NaCl-specific responses to NaCl were weakened in NaCl–acid mixtures, electrolyte-generalist responses to acid and NaCl, which tastes KCl-like, were transmitted undiminished in intensity to the central nervous system. The 2 distinct CT pathways are consistent with known rodent behavioral discriminations. PMID:22451526

The study for the incipient solvation process of NaCl in water: the observation of the NaCl-(H2O)n (n = 1, 2, and 3) complexes using Fourier-transform microwave spectroscopy.

PubMed

Mizoguchi, Asao; Ohshima, Yasuhiro; Endo, Yasuki

2011-08-14

Pure rotational spectra of the sodium chloride-water complexes, NaCl-(H(2)O)(n) (n = 1, 2, and 3), in the vibronic ground state have been observed by a Fourier- transform microwave spectrometer coupled with a laser ablation source. The (37)Cl-isotopic species and a few deuterated species have also been observed. From the analyses of the spectra, the rotational constants, the centrifugal distortion constants, and the nuclear quadrupole coupling constants of the Na and Cl nuclei were determined precisely for all the species. The molecular structures of NaCl-(H(2)O)(n) were determined using the rotational constants and the molecular symmetry. The charge distributions around Na and Cl nuclei in NaCl are dramatically changed by the complex formation with H(2)O. Prominent dependences of the bond lengths r(Na-Cl) on the number of H(2)O were also observed. By a comparison with results of theoretical studies, it is shown that the structure of NaCl-(H(2)O)(3) is approaching to that of the contact ion-pair, which is considered to be an intermediate species in the incipient solvation process.

A high-throughput method to measure NaCl and acid taste thresholds in mice.

PubMed

Ishiwatari, Yutaka; Bachmanov, Alexander A

2009-05-01

To develop a technique suitable for measuring NaCl taste thresholds in genetic studies, we conducted a series of experiments with outbred CD-1 mice using conditioned taste aversion (CTA) and two-bottle preference tests. In Experiment 1, we compared conditioning procedures involving either oral self-administration of LiCl or pairing NaCl intake with LiCl injections and found that thresholds were the lowest after LiCl self-administration. In Experiment 2, we compared different procedures (30-min and 48-h tests) for testing conditioned mice and found that the 48-h test is more sensitive. In Experiment 3, we examined the effects of varying strength of conditioned (NaCl or LiCl taste intensity) and unconditioned (LiCl toxicity) stimuli and concluded that 75-150 mM LiCl or its mixtures with NaCl are the optimal stimuli for conditioning by oral self-administration. In Experiment 4, we examined whether this technique is applicable for measuring taste thresholds for other taste stimuli. Results of these experiments show that conditioning by oral self-administration of LiCl solutions or its mixtures with other taste stimuli followed by 48-h two-bottle tests of concentration series of a conditioned stimulus is an efficient and sensitive method to measure taste thresholds. Thresholds measured with this technique were 2 mM for NaCl and 1 mM for citric acid. This approach is suitable for simultaneous testing of large numbers of animals, which is required for genetic studies. These data demonstrate that mice, like several other species, generalize CTA from LiCl to NaCl, suggesting that they perceive taste of NaCl and LiCl as qualitatively similar, and they also can generalize CTA of a binary mixture of taste stimuli to mixture components.

P2Y2 receptor activation inhibits the expression of the sodium-chloride cotransporter NCC in distal convoluted tubule cells.

PubMed

Gailly, P; Szutkowska, M; Olinger, E; Debaix, H; Seghers, F; Janas, S; Vallon, V; Devuyst, O

2014-11-01

Luminal nucleotide stimulation is known to reduce Na(+) transport in the distal nephron. Previous studies suggest that this mechanism may involve the thiazide-sensitive Na(+)-Cl(-) cotransporter (NCC), which plays an essential role in NaCl reabsorption in the cells lining the distal convoluted tubule (DCT). Here we show that stimulation of mouse DCT (mDCT) cells with ATP or UTP promoted Ca(2+) transients and decreased the expression of NCC at both mRNA and protein levels. Specific siRNA-mediated silencing of P2Y2 receptors almost completely abolished ATP/UTP-induced Ca(2+) transients and significantly reduced ATP/UTP-induced decrease of NCC expression. To test whether local variations in the intracellular Ca(2+) concentration ([Ca(2+)]i) may control NCC transcription, we overexpressed the Ca(2+)-binding protein parvalbumin selectively in the cytosol or in the nucleus of mDCT cells. The decrease in NCC mRNA upon nucleotide stimulation was abolished in cells overexpressing cytosolic PV but not in cells overexpressing either a nuclear-targeted PV or a mutated PV unable to bind Ca(2+). Using a firefly luciferase reporter gene strategy, we observed that the activity of NCC promoter region from -1 to -2,200 bp was not regulated by changes in [Ca(2+)]i. In contrast, high cytosolic calcium level induced instability of NCC mRNA. We conclude that in mDCT cells: (1) P2Y2 receptor is essential for the intracellular Ca(2+) signaling induced by ATP/UTP stimulation; (2) P2Y2-mediated increase of cytoplasmic Ca(2+) concentration down-regulates the expression of NCC; (3) the decrease of NCC expression occurs, at least in part, via destabilization of its mRNA.

Neutralization of Hydroxide Ion in Melt-Grown NaCl Crystals

NASA Technical Reports Server (NTRS)

Otterson, Dumas A.

1961-01-01

Many recent studies of solid-state phenomena, particularly in the area of crystal imperfections, have involved the use of melt-grown NaCl single crystals. Quite often trace impurities in these materials have had a prominent effect on these phenomena. Trace amounts of hydroxide ion have been found in melt-grown NaCl crystals. This paper describes a nondestructive method of neutralizing the hydroxide ion in such crystals. Crystals of similar hydroxide content are maintained at an elevated temperature below the melting point of NaCl in a flowing atmosphere containing. dry hydrogen chloride. Heat treatment is continued until an analysis of the test specimens shows no excess hydroxide ion. A colorimetric method previously described4 is used for this analysis.

The initial stages of NaCl dissolution: Ion or ion pair solvation?

NASA Astrophysics Data System (ADS)

Klimes, Jiri; Michaelides, Angelos

2009-03-01

The interaction of water with rock salt (NaCl) is important in a wide variety of natural processes and human activities. A lot is known about NaCl dissolution at the macroscopic level but we do not yet have a detailed atomic scale picture of how salt crystals dissolve. Here we report an extensive series of density functional theory, forcefield and molecular dynamics studies of water clusters at flat and defective NaCl surfaces and NaCl clusters. The focus is on answering seemingly elementary questions such as how many water molecules are needed before it becomes favorable to extract an ion or a pair of ions from the crystal or the cluster. It turns out, however, that the answers to these questions are not so straightforward: below a certain number of water molecules (˜ 12) solvation of individual ions is less costly and above this number solvation of ion pairs is favored. These results reveal a hitherto unknown complexity in the NaCl dissolution process born out of a subtle interplay between water-water and water-ion interactions.

PSD-95 interacts with NBCn1 and enhances channel-like activity without affecting Na/HCO(3) cotransport.

PubMed

Lee, Soojung; Yang, Han Soo; Kim, Eunjin; Ju, Eun Ji; Kwon, Min Hyung; Dudley, R Kyle; Smith, Yoland; Yun, C Chris; Choi, Inyeong

2012-01-01

The sodium/bicarbonate transporter NBCn1 plays an essential role in intracellular pH regulation and transepithelial HCO(3)(-) movement in the body. NBCn1 also has sodium channel-like activity uncoupled to Na/HCO(3) cotransport. We previously reported that NBCn1 interacts with the postsynaptic density protein PSD-95 in the brain. Here, we elucidated the structural determinant and functional consequence of NBCn1/PSD-95 interaction. In rat hippocampal CA3 neurons, NBCn1 was localized to the postsynaptic membranes of both dendritic shafts and spines and occasionally to the presynaptic membranes. A GST/NBCn1 fusion protein containing the C-terminal 131 amino acids of NBCn1 pulled down PSD-95 from rat brain lysates, whereas GST/NBCn1-ΔETSL (deletion of the last four amino acids) and GST/NBCn2 (NCBE) lacking the same ETSL did not. NBCn1 and PSD-95 were coimmunoprecipitated in HEK 293 cells, and their interaction did not affect the efficacy of PSD-95 to bind to the NMDA receptor NR2A. PSD-95 has negligible effects on intracellular pH changes mediated by NBCn1 in HEK 293 cells and Xenopus oocytes. However, PSD-95 increased an ionic conductance produced by NBCn1 channel-like activity. This increase was abolished by NBCn1-ΔETSL or by the peptide containing the last 15 amino acids of NBCn1. Our data suggest that PSD-95 interacts with NBCn1 and increases its channel-like activity while negligibly affecting Na/HCO(3) cotransport. The possibility that the channel-like activity occurs via an intermolecular cavity of multimeric NBCn1 proteins is discussed. Copyright © 2012 S. Karger AG, Basel.

PSD-95 Interacts with NBCn1 and Enhances Channel-like Activity without Affecting Na/HCO3 Cotransport

PubMed Central

Lee, Soojung; Yang, Han Soo; Kim, Eunjin; Ju, Eun Ji; Kwon, Min Hyung; Dudley, R. Kyle; Smith, Yoland; Yun, C. Chris; Choi, Inyeong

2013-01-01

Background/Aims The sodium/bicarbonate transporter NBCn1 plays an essential role in intracellular pH regulation and transepithelial HCO3− movement in the body. NBCn1 also has sodium channel-like activity uncoupled to Na/HCO3 cotransport. We previously reported that NBCn1 interacts with the postsynaptic density protein PSD-95 in the brain. Here, we elucidated the structural determinant and functional consequence of NBCn1/PSD-95 interaction. Methods: Results In rat hippocampal CA3 neurons, NBCn1 was localized to the postsynaptic membranes of both dendritic shafts and spines and occasionally to the presynaptic membranes. A GST/NBCn1 fusion protein containing the C-terminal 131 amino acids of NBCn1 pulled down PSD-95 from rat brain lysates, whereas GST/NBCn1-ΔETSL (deletion of the last four amino acids) and GST/NBCn2 (NCBE) lacking the same ETSL did not. NBCn1 and PSD-95 were coimmunoprecipitated in HEK 293 cells, and their interaction did not affect the efficacy of PSD-95 to bind to the NMDA receptor NR2A. PSD-95 has negligible effects on intracellular pH changes mediated by NBCn1 in HEK 293 cells and Xenopus oocytes. However, PSD-95 increased an ionic conductance produced by NBCn1 channel-like activity. This increase was abolished by NBCn1-ΔETSL or by the peptide containing the last 15 amino acids of NBCn1. Conclusion Our data suggest that PSD-95 interacts with NBCn1 and increases its channel-like activity while negligibly affecting Na/HCO3 cotransport. The possibility that the channel-like activity occurs via an intermolecular cavity of multimeric NBCn1 proteins is discussed. PMID:23183381

Thermodynamic description of Tc(iv) solubility and hydrolysis in dilute to concentrated NaCl, MgCl2 and CaCl2 solutions.

PubMed

Yalçıntaş, Ezgi; Gaona, Xavier; Altmaier, Marcus; Dardenne, Kathy; Polly, Robert; Geckeis, Horst

2016-06-07

We present the first systematic investigation of Tc(iv) solubility, hydrolysis and speciation in dilute to concentrated NaCl, MgCl2 and CaCl2 systems, and comprehensive thermodynamic and activity models for the system Tc(4+)-H(+)-Na(+)-Mg(2+)-Ca(2+)-OH(-)-Cl(-)-H2O using both SIT and Pitzer approaches. The results are advancing the fundamental scientific understanding of Tc(iv) solution chemistry and are highly relevant in the applied context of nuclear waste disposal. The solubility of Tc(iv) was investigated in carbonate-free NaCl-NaOH (0.1-5.0 M), MgCl2 (0.25-4.5 M) and CaCl2 (0.25-4.5 M) solutions within 2 ≤ pHm≤ 14.5. Undersaturation solubility experiments were performed under an Ar atmosphere at T = 22 ± 2 °C. Strongly reducing conditions (pe + pHm≤ 2) were imposed with Na2S2O4, SnCl2 and Fe powder to stabilize technetium in the +IV redox state. The predominance of Tc(iv) in the aqueous phase was confirmed by solvent extraction and XANES/EXAFS spectroscopy. Solid phase characterization was accomplished after attaining thermodynamic equilibrium using XRD, SEM-EDS, XANES/EXAFS, TG-DTA and quantitative chemical analysis, and indicated that TcO2·0.6H2O(s) exerts solubility-control in all evaluated systems. The definition of the polyatomic Tc3O5(2+) species instead of TcO(2+) is favoured under acidic conditions, consistently with slope analysis (mTcvs. pHm) of the solubility data gained in this work and spectroscopic evidence previously reported in the literature. The additional formation of Tc(iv)-OH/O-Cl aqueous species in concentrated chloride media ([Cl(-)] = 9 M) and pHm≤ 4 is suggested by solubility and EXAFS data. The pH-independent behaviour of the solubility observed under weakly acidic to weakly alkaline pHm conditions can be explained with the equilibrium reaction TcO2·0.6H2O(s) + 0.4H2O(l) ⇔ TcO(OH)2(aq). Solubility data determined in dilute NaCl systems with pHm≥ 11 follow a well-defined slope of +1, consistent with the predominance of

Ncl Synchronously Regulates Na+, K+, and Cl- in Soybean and Greatly Increases the Grain Yield in Saline Field Conditions.

PubMed

Do, Tuyen Duc; Chen, Huatao; Hien, Vu Thi Thu; Hamwieh, Aladdin; Yamada, Tetsuya; Sato, Tadashi; Yan, Yongliang; Cong, Hua; Shono, Mariko; Suenaga, Kazuhiro; Xu, Donghe

2016-01-08

Salt stress inhibits soybean growth and reduces gain yield. Genetic improvement of salt tolerance is essential for sustainable soybean production in saline areas. In this study, we isolated a gene (Ncl) that could synchronously regulate the transport and accumulation of Na(+), K(+), and Cl(-) from a Brazilian soybean cultivar FT-Abyara using map-based cloning strategy. Higher expression of the salt tolerance gene Ncl in the root resulted in lower accumulations of Na(+), K(+), and Cl(-) in the shoot under salt stress. Transfer of Ncl with the Agrobacterium-mediated transformation method into a soybean cultivar Kariyutaka significantly enhanced its salt tolerance. Introgression of the tolerance allele into soybean cultivar Jackson, using DNA marker-assisted selection (MAS), produced an improved salt tolerance line. Ncl could increase soybean grain yield by 3.6-5.5 times in saline field conditions. Using Ncl in soybean breeding through gene transfer or MAS would contribute to sustainable soybean production in saline-prone areas.

Enhancement of the sulfur capture capacity of limestones by the addition of Na2CO3 and NaCl.

PubMed

Laursen, K; Grace, J R; Lim, C J

2001-11-01

The ability of Na2CO3 and NaCl to enhance the sulfur capture capacity of three limestones was evaluated via fixed-bed calcination and sulfation experiments. The tested limestones represent three different sulfation morphologies: unreacted-core, network, and uniformly sulfated. Treatment with aqueous or powdered Na2CO3 significantly increased the Ca-utilization for two stones which normally sulfate in an unreacted-core pattern (20% to 45%) and network pattern (33% to 49%). The increase was lower for the uniformly sulfated stone (44% to 48%). Na2CO3 treatment increased the number of macropores leading to uniform sulfation of all particles, nearly eliminating the normal strong dependence of utilization on limestone type and particle size. The effect of Na2CO3 is believed to be associated with formation of a eutectic melt which enhances ionic diffusion and accelerates molecular rearrangement of the CaO. Treatment with aqueous NaCl solution caused a decrease in utilization, probably due to formation of large grains and plugging of pores caused by formation of a large amount of eutectic melt. The effect of Na2CO3 is less sensitive than that of NaCl to the amount added and the combustion environment (temperature and gas composition). In addition, Na2CO3 neither promotes corrosion nor forms chlorinated byproducts, which are main concerns associated with NaCl. Thus, Na2CO3 appears to have significant advantages over NaCl for enhancement of limestone sulfur capture capacity in fluidized-bed combustors.

Aspects of Salt Tolerance in a NaCl-Selected Stable Cell Line of Citrus sinensis.

PubMed

Ben-Hayyim, G; Kochba, J

1983-07-01

A NaCl-tolerant cell line which was selected from ovular callus of ;Shamouti' orange (Citrus sinensis L. Osbeck) proved to be a true cell line variant. This conclusion is based on the following observations. (a) Cells which have been removed from the selection pressure for at least four passages retain the same NaCl tolerance as do cells which are kept constantly on 0.2 molar NaCl. (b) Na(+) and Cl(-) uptake are considerably lower in salt-tolerant cells (R-10) than in salt-sensitive cells (L-5) at a given external NaCl concentration. (c) Growth of salt-tolerant cells is markedly suppressed upon replacement of NaCl by KCl, whereas the growth of salt-sensitive cells is only slightly affected. Accumulation of K(+) and Cl(-) accompanies the inhibition of growth. Experiments carried out with sodium and potassium sulfate suggest that the toxic effect is due to the accumulated Cl(-). (d) Removal of Ca(2+) from the growth medium severely inhibits the growth of salt-tolerant cells in the presence of NaCl, while it has a minor effect on growth of salt-sensitive cells in the presence of NaCl. (e) Electron micrographs show that the salt-tolerant cells have very big vacuoles when exposed to salt, while the size of the vacuoles of the salt-sensitive cells does not change.

Preparation of Al-La Master Alloy by Thermite Reaction in NaF-NaCl-KCl Molten Salt

NASA Astrophysics Data System (ADS)

Jang, Poknam; Li, Hyonmo; Kim, Wenjae; Wang, Zhaowen; Liu, Fengguo

2015-05-01

A NaF-NaCl-KCl ternary system containing La2O3 was investigated for the preparation of Al-La master alloy by the thermite reaction method. The solubility of La2O3 in NaF-NaCl-KCl molten salt was determined by the method of isothermal solution saturation. Inductively coupled plasma-optical emission spectroscopy and x-ray diffraction (XRD) analyses were used to consider the content of La2O3 in molten salt and the supernatant composition of molten salt after dissolution of La2O3, respectively. The results showed that the content of NaF had a positive influence on the solubility of La2O3 in NaF-NaCl-KCl molten salts, and the solubility of La2O3 could reach 8.71 wt.% in molten salts of 50 wt.%NaF-50 wt.% (44 wt.%NaCl + 56 wt.%KCl). The XRD pattern of cooling molten salt indicated the formation of LaOF in molten salt, which was probably obtained by the reaction between NaF and La2O3. The kinetic study showed that the thermite reaction was in accord with a first-order reaction model. The main influence factors on La content in the Al-La master alloy product, including molten salt composition, amount of Al, concentration of La2O3, stirring, reduction time and temperature, were investigated by single-factor experimentation. The content of La in the Al-La master alloy could be reached to 10.1 wt.%.

Allelic-based gene-gene interaction associated with quantitative traits.

PubMed

Jung, Jeesun; Sun, Bin; Kwon, Deukwoo; Koller, Daniel L; Foroud, Tatiana M

2009-05-01

Recent studies have shown that quantitative phenotypes may be influenced not only by multiple single nucleotide polymorphisms (SNPs) within a gene but also by the interaction between SNPs at unlinked genes. We propose a new statistical approach that can detect gene-gene interactions at the allelic level which contribute to the phenotypic variation in a quantitative trait. By testing for the association of allelic combinations at multiple unlinked loci with a quantitative trait, we can detect the SNP allelic interaction whether or not it can be detected as a main effect. Our proposed method assigns a score to unrelated subjects according to their allelic combination inferred from observed genotypes at two or more unlinked SNPs, and then tests for the association of the allelic score with a quantitative trait. To investigate the statistical properties of the proposed method, we performed a simulation study to estimate type I error rates and power and demonstrated that this allelic approach achieves greater power than the more commonly used genotypic approach to test for gene-gene interaction. As an example, the proposed method was applied to data obtained as part of a candidate gene study of sodium retention by the kidney. We found that this method detects an interaction between the calcium-sensing receptor gene (CaSR), the chloride channel gene (CLCNKB) and the Na, K, 2Cl cotransporter gene (CLC12A1) that contributes to variation in diastolic blood pressure.

K-Cl cotransporters, cell volume homeostasis, and neurological disease

PubMed Central

Kahle, Kristopher T.; Khanna, Arjun R.; Alper, Seth L.; Adragna, Norma C.; Lauf, Peter K.; Sun, Dandan; Delpire, Eric

2016-01-01

K+-Cl− cotransporters (KCCs) were originally characterized as regulators of red blood cell (RBC) volume. Since then, four distinct KCCs have been cloned, and their importance for volume regulation has been demonstrated in other cell types. Genetic models of certain KCCs, such as KCC3, and their inhibitory WNK-STE20/SPS1-related proline/alanine-rich kinase (SPAK) serine-threonine kinases, have demonstrated the evolutionary necessity of these molecules for nervous system cell volume regulation, structure, and function, and their involvement in neurological disease. The recent characterization of a swelling-activated dephosphorylation mechanism that potently stimulates the KCCs has pinpointed a potentially druggable switch of KCC activity. An improved understanding of WNK/SPAK-mediated KCC cell volume regulation in the nervous system might reveal novel avenues for the treatment of multiple neurological diseases. PMID:26142773

Thiazide-sensitive Na+ -Cl- cotransporter (NCC) gene inactivation results in increased duodenal Ca2+ absorption, enhanced osteoblast differentiation and elevated bone mineral density.

PubMed

Hsu, Yu-Juei; Yang, Sung-Sen; Cheng, Chih-Jen; Liu, Shu-Ting; Huang, Shih-Ming; Chau, Tom; Chu, Pauling; Salter, Donald M; Lee, Herng-Sheng; Lin, Shih-Hua

2015-01-01

Inactivation of the thiazide-sensitive sodium chloride cotransporter (NCC) due to genetic mutations in Gitelman's syndrome (GS) or pharmacological inhibition with thiazide diuretics causes hypocalciuria and increased bone mineral density (BMD) with unclear extrarenal calcium (Ca(2+) ) regulation. We investigated intestinal Ca(2+) absorption and bone Ca(2+) metabolism in nonsense Ncc Ser707X (S707X) homozygous knockin mice (Ncc(S707X/S707X) mice). Compared to wild-type and heterozygous knockin littermates, Ncc(S707X/S707X) mice had increased intestinal absorption of (45) Ca(2+) and expression of the active Ca(2+) transport machinery (transient receptor potential vanilloid 6, calbindin-D9K , and plasma membrane Ca(2+) ATPase isoform 1b). Ncc(S707X/S707X) mice had also significantly increased Ca(2+) content accompanied by greater mineral apposition rate (MAR) in their femurs and higher trabecular bone volume, cortical bone thickness, and BMD determined by μCT. Their osteoblast differentiation markers, such as bone alkaline phosphatase, procollagen I, osteocalcin, and osterix, were also significantly increased while osteoclast activity was unaffected. Analysis of marrow-derived bone cells, either treated with thiazide or directly cultured from Ncc S707X knockin mice, showed that the differentiation of osteoblasts was associated with increased phosphorylation of mechanical stress-induced focal adhesion kinase (FAK) and extracellular signal-regulated kinase (ERK). In conclusion, NCC inhibition stimulates duodenal Ca(2+) absorption as well as osteoblast differentiation and bone Ca(2+) storage, possibly through a FAK/ERK dependent mechanism. © 2014 American Society for Bone and Mineral Research.

Age related decreases in neural sensitivity to NaCl in SHR-SP.

PubMed

Osada, Kazumi; Komai, Michio; Bryant, Bruce P; Suzuki, Hitoshi; Tsunoda, Kenji; Furukawa, Yuji

2003-03-01

To determine whether neurophysiological taste responses of young and old rats are different, recordings were made from the whole chorda tympani nerve which innervates taste buds on the anterior tongue. SHR-SP (Stroke-Prone Spontaneously Hypertensive Rats) in two age groups were studied. Chemical stimuli included single concentrations of 250 mM NH(4)Cl, 100 mM NaCl, 100 mM KCl, 500 mM sucrose, 20 mM quinine-hydrochloride, 10 mM HCl, 10 mM monosodium glutamate (MSG), 10 mM L- glutamic acid (L-Glu) and an NaCl concentration series. The magnitude of the neural response (response ratio) was calculated by dividing the amplitude of the integrated response by the amplitude of the spontaneous activity that preceded it. Substantial neural responses to all chemicals were obtained at both ages. The responses to KCl, sucrose, quinine-hydrochloride, HCl, monosodium glutamate (MSG) and glutamic acid (Glu) did not change with age, but the response to NaCl did decrease significantly. The profile of the response/concentration function for NaCl differed with age. In particular, the responses to solutions more concentrated than 100 mM NaCl were significantly weaker in aged than in young SHR-SPs. We also observed that recovery from amiloride treatment on the tongue of SHR-SPs was faster in aged rats than in young ones, suggesting that there is some functional difference in the sodium-specific channels on the taste cell. These results suggest that aged SHR-SP may be less able than young SHR-SPs to discriminate among higher concentrations of NaCl solutions.

Na+-glucose cotransporter is also expressed in mesothelium of species with thick visceral pleura.

PubMed

Sironi, Chiara; Bodega, Francesca; Porta, Cristina; Monaco, Ario; Zocchi, Luciano; Agostoni, Emilio

2008-05-31

Molecular evidence for Na+-glucose cotransporter (SGLT1) in rabbit pleural mesothelium has been recently provided, confirming earlier functional findings on solute-coupled liquid absorption from rabbit pleural space. In this research we checked whether SGLT1 is also expressed in pleural mesothelium of species with thick visceral pleura, which receives blood from systemic circulation, but drains it into pulmonary veins. To this end immunoblot assays were performed on total protein extract of scraped visceral and parietal mesothelium of lambs and adult sheep, and of a human mesothelial cell line. All of them showed SGLT1 specific bands. Moreover, confocal immunofluorescence images of lamb pleural mesothelium showed that SGLT1 is located in apical membrane. Therefore, a solute-coupled liquid absorption should also occur from pleural space of species with thick visceral pleura. Because of this protein-free liquid entering interstitium between visceral mesothelium and capillaries, inherent Starling forces should be different than hitherto considered, and visceral pleura capillaries could absorb liquid even in these species.

Cation-Coupled Bicarbonate Transporters

PubMed Central

Aalkjaer, Christian; Boedtkjer, Ebbe; Choi, Inyeong; Lee, Soojung

2016-01-01

Cation-coupled HCO3− transport was initially identified in the mid-1970s when pioneering studies showed that acid extrusion from cells is stimulated by CO2/HCO3− and associated with Na+ and Cl− movement. The first Na+-coupled bicarbonate transporter (NCBT) was expression-cloned in the late 1990s. There are currently five mammalian NCBTs in the SLC4-family: the electrogenic Na,HCO3-cotransporters NBCe1 and NBCe2 (SLC4A4 and SLC4A5 gene products); the electroneutral Na,HCO3-cotransporter NBCn1 (SLC4A7 gene product); the Na+-driven Cl,HCO3-exchanger NDCBE (SLC4A8 gene product); and NBCn2/NCBE (SLC4A10 gene product), which has been characterized as an electroneutral Na,HCO3-cotransporter or a Na+-driven Cl,HCO3-exchanger. Despite the similarity in amino acid sequence and predicted structure among the NCBTs of the SLC4-family, they exhibit distinct differences in ion dependency, transport function, pharmacological properties, and interactions with other proteins. In epithelia, NCBTs are involved in transcellular movement of acid-base equivalents and intracellular pH control. In nonepithelial tissues, NCBTs contribute to intracellular pH regulation; and hence, they are crucial for diverse tissue functions including neuronal discharge, sensory neuron development, performance of the heart, and vascular tone regulation. The function and expression levels of the NCBTs are generally sensitive to intracellular and systemic pH. Animal models have revealed pathophysiological roles of the transporters in disease states including metabolic acidosis, hypertension, visual defects, and epileptic seizures. Studies are being conducted to understand the physiological consequences of genetic polymorphisms in the SLC4-members, which are associated with cancer, hypertension, and drug addiction. Here, we describe the current knowledge regarding the function, structure, and regulation of the mammalian cation-coupled HCO3− transporters of the SLC4-family. PMID:25428855

Effects of NaCl and CaCl2 on Water Transport across Root Cells of Maize (Zea mays L.) Seedlings 1

PubMed Central

Azaizeh, Hassan; Gunse, Benito; Steudle, Ernst

1992-01-01

The effect of salinity and calcium levels on water flows and on hydraulic parameters of individual cortical cells of excised roots of young maize (Zea mays L. cv Halamish) plants have been measured using the cell pressure probe. Maize seedlings were grown in one-third strength Hoagland solution modified by additions of NaCl and/or extra calcium so that the seedlings received one of four treatments: control; +100 millimolar NaCl; +10 millimolar CaCl2; +100 millimolar NaCl + 10 millimolar CaCl2. From the hydrostatic and osmotic relaxations of turgor, the hydraulic conductivity (Lp) and the reflection coefficient (σs) of cortical cells of different root layers were determined. Mean Lp values in the different layers (first to third, fourth to sixth, seventh to ninth) of the four different treatments ranged from 11.8 to 14.5 (Control), 2.5 to 3.8 (+NaCl), 6.9 to 8.7 (+CaCl2), and 6.6 to 7.2 · 10−7 meter per second per megapascal (+NaCl + CaCl2). These results indicate that salinization of the growth media at regular calcium levels (0.5 millimolar) decreased Lp significantly (three to six times). The addition of extra calcium (10 millimolar) to the salinized media produced compensating effects. Mean cell σs values of NaCl ranged from 1.08 to 1.16, 1.15 to 1.22, 0.94 to 1.00, and 1.32 to 1.46 in different root cell layers of the four different treatments, respectively. Some of these σs values were probably overestimated due to an underestimation of the elastic modulus of cells, σs values of close to unity were in line with the fact that root cell membranes were practically not permeable to NaCl. However, the root cylinder exhibited some permeability to NaCl as was demonstrated by the root pressure probe measurements that resulted in σsr of less than unity. Compared with the controls, salinity and calcium increased the root cell diameter. Salinized seedlings grown at regular calcium levels resulted in shorter cell length compared with control (by a factor of 2

Hygroscopic Behavior of Multicomponent Aerosols Involving NaCl and Dicarboxylic Acids.

PubMed

Peng, Chao; Jing, Bo; Guo, Yu-Cong; Zhang, Yun-Hong; Ge, Mao-Fa

2016-02-25

Atmospheric aerosols are usually complex mixtures of inorganic and organic compounds. The hygroscopicity of mixed particles is closely related to their chemical composition and interactions between components, which is still poorly understood. In this study, the hygroscopic properties of submicron particles composed of NaCl and dicarboxylic acids including oxalic acid (OA), malonic acid (MA), and succinic acid (SA) with various mass ratios are investigated with a hygroscopicity tandem differential mobility analyzer (HTDMA) system. Both the Zdanovskii-Stokes-Robinson (ZSR) method and extended aerosol inorganics model (E-AIM) are applied to predict the water uptake behaviors of sodium chloride/dicarboxylic acid mixtures. For NaCl/OA mixed particles, the measured growth factors were significantly lower than predictions from the model methods, indicating a change in particle composition caused by chloride depletion. The hygroscopic growth of NaCl/MA particles was well described by E-AIM, and that of NaCl/SA particles was dependent upon mixing ratio. Compared with model predictions, it was determined that water uptake of the NaCl/OA mixture could be enhanced and could be closer to the predictions by addition of levoglucosan or malonic acid, which retained water even at low relative humidity (RH), leading to inhibition of HCl evaporation during dehydration. These results demonstrate that the coexisting hygroscopic species have a strong influence on the phase state of particles, thus affecting chemical interactions between inorganic and organic compounds as well as the overall hygroscopicity of mixed particles.

NaCl strongly modifies the physicochemical properties of aluminum hydroxide vaccine adjuvants.

PubMed

Art, Jean-François; Vander Straeten, Aurélien; Dupont-Gillain, Christine C

2017-01-30

The immunostimulation capacity of most vaccines is enhanced through antigen adsorption on aluminum hydroxide (AH) adjuvants. Varying the adsorption conditions, i.e. pH and ionic strength (I), changes the antigen adsorbed amount and therefore the ability of the vaccine to stimulate the immune system. Vaccine formulations are thus resulting from an empirical screening of the adsorption conditions. This work aims at studying the physicochemical effects of adjusting the ionic strength of commercial AH adjuvant particles suspensions with sodium chloride (NaCl). X-ray photoelectron spectroscopy data show that AH particles surface chemical composition is neither altered by I adjustment with NaCl nor by deposition on gold surfaces. The latter result provides the opportunity to use AH-coated gold surfaces as a platform for advanced surface analysis of adjuvant particles, e.g. by atomic force microscopy (AFM). The morphology of adjuvant particles recovered from native and NaCl-treated AH suspensions, as studied by scanning electron microscopy and AFM, reveals that AH particles aggregation state is significantly altered by NaCl addition. This is further confirmed by nitrogen adsorption experiments: I adjustment to 150mM with NaCl strongly promotes AH particles aggregation leading to a strong decrease of the developed specific surface area. This work thus evidences the effect of NaCl on AH adjuvant structure, which may lead to alteration of formulated vaccines and to misinterpretation of data related to antigen adsorption on adjuvant particles. Copyright © 2016 Elsevier B.V. All rights reserved.

Dehydration process in NaCl solutions under various external electric fields

NASA Astrophysics Data System (ADS)

Kadota, Kazunori; Shimosaka, Atsuko; Shirakawa, Yoshiyuki; Hidaka, Jusuke

2007-06-01

Ionic motions at solid-liquid interface in supersaturated NaCl solutions have been investigated by molecular dynamics (MD) simulation for understanding crystal growth processes. The density profile in the vicinity of the interfaces between NaCl(100) and the supersaturated NaCl solution was calculated. Diffusion coefficients of water molecules in the solution were estimated as a function of distance from the crystal interface. It turned out that the structure and dynamics of the solution in the interfaces was different from those of bulk solution owing to electric fields depending on the surface charge. Therefore, the electric field was applied to the supersaturated solutions and dehydration phenomenon occurring in the process of the crystal growth was discussed. As the electric field increased, it was observed that the Na+ keeping strongly hydration structure broke out by the electric force. In supersaturated concentration, the solution structure is significantly different from that of dilution and has a complicated structure with hydration ions and clusters of NaCl. If the electric fields were applied to the solutions, the breakout of hydration structure was not affected with increasing the supersaturated ratio. This reason is that the cluster structures are destroyed by the electric force. The situation depends on the electric field or crystal surface structure.

Phase relations in the system NaCl-KCl-H2O II: Differential thermal analysis of the halite liquidus in the NaCl-H2O binary above 450°c

USGS Publications Warehouse

Gunter, W.D.; Chou, I.-Ming; Girsperger, Sven

1983-01-01

The solubility of halite can be expressed as a function of the mole-fractional-based activity of NaCl in the liquid phase (L) in temperature (T, °K) and pressure (P, bars) In  Our liquidus data (based on 10 compositions) above 500 bars for these brines were combined with this equation to generate activity coefficients of NaCl which were fit within their experimental uncertainties to the following one parameter Margules equation In . Concentrated solutions of NaCl show negative deviations from ideality which rapidly increase in magnitude with decreasing XNaCl.

The effect of NaCl 0.9% and NaCl 0.45% on sodium, chloride, and acid-base balance in a PICU population.

PubMed

Almeida, Helena Isabel; Mascarenhas, Maria Inês; Loureiro, Helena Cristina; Abadesso, Clara S; Nunes, Pedro S; Moniz, Marta S; Machado, Maria Céu

2015-01-01

To study the effect of two intravenous maintenance fluids on plasma sodium (Na), and acid-base balance in pediatric intensive care patients during the first 24h of hospitalization. A prospective randomized controlled study was performed, which allocated 233 patients to groups: (A) NaCl 0.9% or (B) NaCl 0.45%. Patients were aged 1 day to 18 years, had normal electrolyte concentrations, and suffered an acute insult (medical/surgical). change in plasma sodium. Parametric tests: t-tests, ANOVA, X(2) statistical significance level was set at α=0.05. Group A (n=130): serum Na increased by 2.91 (±3.9)mmol/L at 24h (p<0.01); 2% patients had Na higher than 150 mmol/L. Mean urinary Na: 106.6 (±56.8)mmol/L. No change in pH at 0 and 24h. Group B (n=103): serum Na did not display statistically significant changes. Fifteen percent of the patients had Na<135 mmol/L at 24h. The two fluids had different effects on respiratory and post-operative situations. The use of saline 0.9% was associated with a lower incidence of electrolyte disturbances. Copyright © 2015 Sociedade Brasileira de Pediatria. Published by Elsevier Editora Ltda. All rights reserved.

The use of NaCl addition for the improvement of polyhydroxyalkanoate production by Cupriavidus necator.

PubMed

Passanha, Pearl; Kedia, Gopal; Dinsdale, Richard M; Guwy, Alan J; Esteves, Sandra R

2014-07-01

External stress factors in the form of ionic species or temperature increases have been shown to produce a stress response leading to enhanced PHA production. The effect of five different NaCl concentrations, namely 3.5, 6.5, 9, 12 and 15 g/l NaCl on PHA productivity using Cupriavidus necator has been investigated alongside a control (no added NaCl). A dielectric spectroscopy probe was used to measure PHA accumulation online in conjunction with the chemical offline analysis of PHA. The highest PHA production was obtained with the addition of 9 g/l NaCl, which yielded 30% higher PHA than the control. Increasing the addition of NaCl to 15 g/l was found to inhibit the production of PHA. NaCl addition can therefore be used as a simple, low cost, sustainable, non toxic and non reactive external stress strategy for increasing PHA productivity. Copyright © 2014 Elsevier Ltd. All rights reserved.

Measurement and Modeling of Setschenow Constants for Selected Hydrophilic Compounds in NaCl and CaCl2 Simulated Carbon Storage Brines.

PubMed

Burant, Aniela; Lowry, Gregory V; Karamalidis, Athanasios K

2017-06-20

Carbon capture, utilization, and storage (CCUS), a climate change mitigation strategy, along with unconventional oil and gas extraction, generates enormous volumes of produced water containing high salt concentrations and a litany of organic compounds. Understanding the aqueous solubility of organic compounds related to these operations is important for water treatment and reuse alternatives, as well as risk assessment purposes. The well-established Setschenow equation can be used to determine the effect of salts on aqueous solubility. However, there is a lack of reported Setschenow constants, especially for polar organic compounds. In this study, the Setschenow constants for selected hydrophilic organic compounds were experimentally determined, and linear free energy models for predicting the Setschenow constant of organic chemicals in concentrated brines were developed. Solid phase microextraction was employed to measure the salting-out behavior of six selected hydrophilic compounds up to 5 M NaCl and 2 M CaCl 2 and in Na-Ca-Cl brines. All compounds, which include phenol, p-cresol, hydroquinone, pyrrole, hexanoic acid, and 9-hydroxyfluorene, exhibited log-linear behavior up to these concentrations, meaning Setschenow constants previously measured at low salt concentrations can be extrapolated up to high salt concentrations for hydrophilic compounds. Setschenow constants measured in NaCl and CaCl 2 brines are additive for the compounds measured here; meaning Setschenow constants measured in single salt solutions can be used in multiple salt solutions. The hydrophilic compounds in this study were selected to elucidate differences in salting-out behavior based on their chemical structure. Using data from this study, as well as literature data, linear free energy relationships (LFERs) for prediction of NaCl, CaCl 2 , LiCl, and NaBr Setschenow constants were developed and validated. Two LFERs were improved. One LFER uses the Abraham solvation parameters, which include

Identification of a 3rd Na+ Binding Site of the Glycine Transporter, GlyT2

PubMed Central

Subramanian, Nandhitha; Scopelitti, Amanda J.; Carland, Jane E.; Ryan, Renae M.; O’Mara, Megan L.; Vandenberg, Robert J.

2016-01-01

The Na+/Cl- dependent glycine transporters GlyT1 and GlyT2 regulate synaptic glycine concentrations. Glycine transport by GlyT2 is coupled to the co-transport of three Na+ ions, whereas transport by GlyT1 is coupled to the co-transport of only two Na+ ions. These differences in ion-flux coupling determine their respective concentrating capacities and have a direct bearing on their functional roles in synaptic transmission. The crystal structures of the closely related bacterial Na+-dependent leucine transporter, LeuTAa, and the Drosophila dopamine transporter, dDAT, have allowed prediction of two Na+ binding sites in GlyT2, but the physical location of the third Na+ site in GlyT2 is unknown. A bacterial betaine transporter, BetP, has also been crystallized and shows structural similarity to LeuTAa. Although betaine transport by BetP is coupled to the co-transport of two Na+ ions, the first Na+ site is not conserved between BetP and LeuTAa, the so called Na1' site. We hypothesized that the third Na+ binding site (Na3 site) of GlyT2 corresponds to the BetP Na1' binding site. To identify the Na3 binding site of GlyT2, we performed molecular dynamics (MD) simulations. Surprisingly, a Na+ placed at the location consistent with the Na1' site of BetP spontaneously dissociated from its initial location and bound instead to a novel Na3 site. Using a combination of MD simulations of a comparative model of GlyT2 together with an analysis of the functional properties of wild type and mutant GlyTs we have identified an electrostatically favorable novel third Na+ binding site in GlyT2 formed by Trp263 and Met276 in TM3, Ala481 in TM6 and Glu648 in TM10. PMID:27337045

Na+-taurocholate cotransporting polypeptide (NTCP/SLC10A1) ortholog in the marine skate Leucoraja erinacea is not a physiological bile salt transporter

PubMed Central

Yu, Dongke; Zhang, Han; Lionarons, Daniel A.; Boyer, James L.

2017-01-01

The Na+-dependent taurocholate cotransporting polypeptide (NTCP/SLC10A1) is a hepatocyte-specific solute carrier, which plays an important role in maintaining bile salt homeostasis in mammals. The absence of a hepatic Na+-dependent bile salt transport system in marine skate and rainbow trout raises a question regarding the function of the Slc10a1 gene in these species. Here, we have characterized the Slc10a1 gene in the marine skate, Leucoraja erinacea. The transcript of skate Slc10a1 (skSlc10a1) encodes 319 amino acids and shares 46% identity to human NTCP (hNTCP) with similar topology to mammalian NTCP. SkSlc10a1 mRNA was mostly confined to the brain and testes with minimal expression in the liver. An FXR-bile salt reporter assay indicated that skSlc10a1 transported taurocholic acid (TCA) and scymnol sulfate, but not as effectively as hNTCP. An [3H]TCA uptake assay revealed that skSlc10a1 functioned as a Na+-dependent transporter, but with low affinity for TCA (Km = 92.4 µM) and scymnol sulfate (Ki = 31 µM), compared with hNTCP (TCA, Km = 5.4 µM; Scymnol sulfate, Ki = 3.5 µM). In contrast, the bile salt concentration in skate plasma was 2 µM, similar to levels seen in mammals. Interestingly, skSlc10a1 demonstrated transport activity for the neurosteroids dehydroepiandrosterone sulfate and estrone-3-sulfate at physiological concentration, similar to hNTCP. Together, our findings indicate that skSlc10a1 is not a physiological bile salt transporter, providing a molecular explanation for the absence of a hepatic Na+-dependent bile salt uptake system in skate. We speculate that Slc10a1 is a neurosteroid transporter in skate that gained its substrate specificity for bile salts later in vertebrate evolution. PMID:28077388

Na+-taurocholate cotransporting polypeptide (NTCP/SLC10A1) ortholog in the marine skate Leucoraja erinacea is not a physiological bile salt transporter.

PubMed

Yu, Dongke; Zhang, Han; Lionarons, Daniel A; Boyer, James L; Cai, Shi-Ying

2017-04-01

The Na + -dependent taurocholate cotransporting polypeptide (NTCP/SLC10A1) is a hepatocyte-specific solute carrier, which plays an important role in maintaining bile salt homeostasis in mammals. The absence of a hepatic Na + -dependent bile salt transport system in marine skate and rainbow trout raises a question regarding the function of the Slc10a1 gene in these species. Here, we have characterized the Slc10a1 gene in the marine skate, Leucoraja erinacea The transcript of skate Slc10a1 (skSlc10a1) encodes 319 amino acids and shares 46% identity to human NTCP (hNTCP) with similar topology to mammalian NTCP. SkSlc10a1 mRNA was mostly confined to the brain and testes with minimal expression in the liver. An FXR-bile salt reporter assay indicated that skSlc10a1 transported taurocholic acid (TCA) and scymnol sulfate, but not as effectively as hNTCP. An [ 3 H]TCA uptake assay revealed that skSlc10a1 functioned as a Na + -dependent transporter, but with low affinity for TCA ( K m = 92.4 µM) and scymnol sulfate ( K i = 31 µM), compared with hNTCP (TCA, K m = 5.4 µM; Scymnol sulfate, K i = 3.5 µM). In contrast, the bile salt concentration in skate plasma was 2 µM, similar to levels seen in mammals. Interestingly, skSlc10a1 demonstrated transport activity for the neurosteroids dehydroepiandrosterone sulfate and estrone-3-sulfate at physiological concentration, similar to hNTCP. Together, our findings indicate that skSlc10a1 is not a physiological bile salt transporter, providing a molecular explanation for the absence of a hepatic Na + -dependent bile salt uptake system in skate. We speculate that Slc10a1 is a neurosteroid transporter in skate that gained its substrate specificity for bile salts later in vertebrate evolution. Copyright © 2017 the American Physiological Society.

Electrical conductivity of H2O-NaCl fluids to 10 kbar

NASA Astrophysics Data System (ADS)

Sinmyo, R.; Keppler, H.

2016-12-01

Magnetotelluric studies often reveal zones of elevated electrical conductivity in the mantle wedge above subducting slabs, in the deep crust below fold belts, or below active volcanoes. Since both aqueous fluids and hydrous silivate melts may be highly conductive, they may both account for these observations. Distinguishing between these two posssibilities, however, is difficult. One reason for this problem is that while there are very good conductivity data for silicate melts, such data do not exist for aqueous fluids under the relevant conditions of pressure, temperature and solute concentration. Most crustal and mantle fluids likely contain some NaCl, which greatly enhances conductivity due to its partial dissociation into Na+ and Cl-. We therefore studied the electrical conductivity of 0.01, 0.1 and 1 m NaCl solutions in water to 10 kbar and 600 °C. The measurements were carried out in externally-heated diamond cells containing two gaskets separated by an insulating ring of diamond, following a method described by Ni et al. (2014). The two gaskets were used as electrodes and full impedance spectra were measured from 30 Hz to 10 MHz using a Solartron 1260 impedance analyzer. Electrical conductivity was generally found to increase with pressure temperature, and fluid density. The conductivity increase observed upon variation of NaCl concentration from 0.1m to 1m was smaller than from 0.01m to 0.1m, which reflects the reduced degree of dissociation at high NaCl concentration. In general, the data show that already a very small fraction of NaCl-bearing aqueous fluid is sufficient to enhance bulk conductivities to values that would be expected for a high degree of partial melting. Accordingly, aqueous fluids may be distinguished from hydrous melts by comparing magnetotelluric and seismic data. H2O-NaCl fluids may enhance electrical conductivities with little disturbance of vp or vp/vs ratios.

Zero-gravity growth of NaF-NaCl eutectics in the NASA Skylab program

NASA Technical Reports Server (NTRS)

Yue, A. S.; Allen, F. G.; Yu, J. G.

1976-01-01

Continuous and discontinuous NaF fibers, embedded in a NaCl matrix, were produced in space and on earth. The production of continuous fibers in a eutectic mixture is attributed to the absence of convection current in the liquid during solidification in space. Image transmission and optical transmittance measurements of transverse sections of the space-grown and earth-grown ingots were made with a light microscope and a spectrometer. It is shown that better optical properties were obtained from samples grown in space. This was attributed to a better alignment of NaF fibers along the ingot axis. A new concept is advanced to explain the phenomenon of transmittance versus far infrared wavelength of the directionally solidified NaCl-NaF eutectic in terms of the two-dimensional Bragg Scattering and the polarization effect of Rayleigh scattering. This concept can be applied to other eutectic systems as long as the index of refraction of the matrix over a range of wavelengths is known. Experimental data are in agreement with the theoretical prediction.

A systematic proteomic analysis of NaCl-stressed germinating maize seeds.

PubMed

Meng, Ling-Bo; Chen, Yi-Bo; Lu, Tian-Cong; Wang, Yue-Feng; Qian, Chun-Rong; Yu, Yang; Ge, Xuan-Liang; Li, Xiao-Hui; Wang, Bai-Chen

2014-05-01

Salt (NaCl) is a common physiological stressor of plants. To better understand how germinating seeds respond to salt stress, we examined the changes that occurred in the proteome of maize seeds during NaCl-treated germination. Phenotypically, salt concentrations less than 0.2 M appear to delay germination, while higher concentrations disrupt development completely, leading to seed death. The identities of 96 proteins with expression levels altered by NaCl-incubation were established using 2-DE-MALDI-TOF-MS and 2-DE-MALDI-TOF-MS/MS. Of these 96 proteins, 79 were altered greater than twofold when incubated with a 0.2 M salt solution, while 51 were altered when incubated with a 0.1 M salt solution. According to their functional annotations in the Swiss-Prot protein-sequence databases, these proteins are mainly involved in seed storage, energy metabolism, stress response, and protein metabolism. Notably, the expression of proteins that respond to abscisic acid signals increased in response to salt stress. The results of this study provide important clues as to how NaCl stresses the physiology of germinating maize seeds.

Fabrication of large binary colloidal crystals with a NaCl structure

PubMed Central

Vermolen, E. C. M.; Kuijk, A.; Filion, L. C.; Hermes, M.; Thijssen, J. H. J.; Dijkstra, M.; van Blaaderen, A.

2009-01-01

Binary colloidal crystals offer great potential for tuning material properties for applications in, for example, photonics, semiconductors and spintronics, because they allow the positioning of particles with quite different characteristics on one lattice. For micrometer-sized colloids, it is believed that gravity and slow crystallization rates hinder the formation of high-quality binary crystals. Here, we present methods for growing binary colloidal crystals with a NaCl structure from relatively heavy, hard-sphere-like, micrometer-sized silica particles by exploring the following external fields: electric, gravitational, and dielectrophoretic fields and a structured surface (colloidal epitaxy). Our simulations show that the free-energy difference between the NaCl and NiAs structures, which differ in their stacking of the hexagonal planes of the larger spheres, is very small (≈0.002 kBT). However, we demonstrate that the fcc stacking of the large spheres, which is crucial for obtaining the pure NaCl structure, can be favored by using a combination of the above-mentioned external fields. In this way, we have successfully fabricated large, 3D, oriented single crystals having a NaCl structure without stacking disorder. PMID:19805259

Constant Enthalpy Change Value during Pyrophosphate Hydrolysis within the Physiological Limits of NaCl*

PubMed Central

Wakai, Satoshi; Kidokoro, Shun-ichi; Masaki, Kazuo; Nakasone, Kaoru; Sambongi, Yoshihiro

2013-01-01

A decrease in water activity was thought to result in smaller enthalpy change values during PPi hydrolysis, indicating the importance of solvation for the reaction. However, the physiological significance of this phenomenon is unknown. Here, we combined biochemistry and calorimetry to solve this problem using NaCl, a physiologically occurring water activity-reducing reagent. The pyrophosphatase activities of extremely halophilic Haloarcula japonica, which can grow at ∼4 m NaCl, and non-halophilic Escherichia coli and Saccharomyces cerevisiae were maximal at 2.0 and 0.1 m NaCl, respectively. Thus, halophilic and non-halophilic pyrophosphatases exhibit distinct maximal activities at different NaCl concentration ranges. Upon calorimetry, the same exothermic enthalpy change of −35 kJ/mol was obtained for the halophile and non-halophiles at 1.5–4.0 and 0.1–2.0 m NaCl, respectively. These results show that solvation changes caused by up to 4.0 m NaCl (water activity of ∼0.84) do not affect the enthalpy change in PPi hydrolysis. It has been postulated that PPi is an ATP analog, having a so-called high energy phosphate bond, and that the hydrolysis of both compounds is enthalpically driven. Therefore, our results indicate that the hydrolysis of high energy phosphate compounds, which are responsible for biological energy conversion, is enthalpically driven within the physiological limits of NaCl. PMID:23965994

High-pressure NaCl-phase of tetrahedral compounds

NASA Astrophysics Data System (ADS)

Soma, T.; -Matsuo Kagaya, H.

1984-04-01

The phase transition of tetrahedral compounds such as GaP, InP, ZnS, ZnSe, ZnTe and CdTe under pressure is investigated from the electronic theory of solids by using our recently presented binding force, which includes mainly covalent interactions in the pseudopotential formalism and partially ionic interactions. The partially ionic forces give the important contributions to the high-pressure phase and stabilize the NaCl-type structure for the high-pressure phase of these compounds, although not reported for GaP experimentally. Then, the numerical results such as the transition pressure, the volume-discontinuity, the transition heat with respect to the pressure-induced phase transition from the zinc-blende-to the NaCl-type lattice are obtained theoretically.

The effect of NaCl/g/ on the Na2SO4-induced hot corrosion of NiAl

NASA Technical Reports Server (NTRS)

Smeggil, J. G.; Bornstein, N. S.; Decrescente, M. A.

1977-01-01

Studies have been performed to examine the effect of NaCl vapor on the Na2SO4-induced hot corrosion of the alumina former NiAl. In the incubation period associated with such hot corrosion, NaCl(g) has been shown to be effective in removing aluminum from below the protective alumina scale and redepositing it as Al2O3 whiskers on the surface of the Na2SO4-coated sample. Similar effects seen in simple oxidation are associated with isothermal rupturing of the protective alumina scale.

Batteries: An Advanced Na-FeCl2 ZEBRA Battery for Stationary Energy Storage Application

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Guosheng; Lu, Xiaochuan; Kim, Jin Yong

2015-06-17

Sodium-metal chloride batteries, ZEBRA, are considered as one of the most important electrochemical devices for stationary energy storage applications because of its advantages of good cycle life, safety, and reliability. However, sodium-nickel chloride (Na-NiCl2) batteries, the most promising redox chemistry in ZEBRA batteries, still face great challenges for the practical application due to its inevitable feature of using Ni cathode (high materials cost). In this work, a novel intermediate-temperature sodium-iron chloride (Na-FeCl2) battery using a molten sodium anode and Fe cathode is proposed and demonstrated. The first use of unique sulfur-based additives in Fe cathode enables Na-FeCl2 batteries can bemore » assembled in the discharged state and operated at intermediate-temperature (<200°C). The results in this work demonstrate that intermediate-temperature Na-FeCl2 battery technology could be a propitious solution for ZEBRA battery technologies by replacing the traditional Na-NiCl2 chemistry.« less

A combined physicochemical-biological method of NaCl extraction from the irrigation solution in the BTLSS

NASA Astrophysics Data System (ADS)

Trifonov, Sergey V.; Tikhomirov, Alexander A.; Ushakova, Sofya; Tikhomirova, Natalia

2016-07-01

The use of processed human wastes as a source of minerals for plants in closed biotechnical life support systems (BTLSS) leads to high salt levels in the irrigation solution, as urine contains high concentrations of NaCl. It is important to develop a process that would effectively decrease NaCl concentration in the irrigation solution and return this salt to the crew's diet. The salt-tolerant plants (Salicornia europea) used to reduce NaCl concentration in the irrigation solution require higher salt concentrations than those of the solution, and this problem cannot be resolved by concentrating the solution. At the same time, NaCl extracted from mineralized wastes by physicochemical methods is not pure enough to be included in the crew's diet. This study describes an original physicochemical method of NaCl extraction from the solution, which is intended to be used in combination with the biological method of NaCl extraction by using saltwort plants. The physicochemical method produces solutions with high NaCl concentrations, and saltwort plants serve as a biological filter in the final phase, to produce table salt. The study reports the order in which physicochemical and biological methods of NaCl extraction from the irrigation solution should be used to enable rapid and effective inclusion of NaCl into the cycling of the BTLSS with humans. This study was carried out in the IBP SB RAS and supported by the grant of the Russian Science Foundation (Project No. 14-14-00599).

Shape-memory NiTi foams produced by replication of NaCl space-holders.

PubMed

Bansiddhi, A; Dunand, D C

2008-11-01

NiTi foams were created with a structure (32-36% open pores 70-400 microm in size) and mechanical properties (4-25 GPa stiffness, >1000 MPa compressive strength, >42% compressive ductility, and shape-memory strains up to 4%) useful for bone implant applications. A mixture of NiTi and NaCl powders was hot-isostatically pressed at 950 and 1065 degrees C and the NaCl phase was then dissolved in water. The resulting NiTi foams show interconnected pores that replicate the shape and size of the NaCl powders, indicating that NiTi powders densified significantly before NaCl melted at 801 degrees C. Densifying NiTi or other metal powders above the melting point of the space-holder permits the use of NaCl, with the following advantages compared with higher-melting, solid space-holders such as oxides and fluorides used to date: (i) no temperature limit for densification; (ii) lower cost; (iii) greater flexibility in powder (and thus pore) shape; (iv) faster dissolution; (v) reduced metal corrosion during dissolution; (vi) lower toxicity if space-holder residues remain in the foam.

The stability of Cl-CO3-scapolite relative to plagioclase + CaCO3 + CaSO4 in the presence of NaCl brines as a function of P-T-XNaCl

NASA Astrophysics Data System (ADS)

Harlov, D. E.; Budzyn, B.

2008-12-01

Cl-CO3-scapolite [(Na,Ca)4[Al3 (Al,Si) 3 Si3 O24](Cl, CO3 , SO4 )] occurs as a common partial to total alteration of plagioclase in deep-crustal xenoliths, skarns, marbles, gabbros, metabasites, calc-silicate gneisses, as well as in quartzofeldspathic granulite-facies rocks in general (Moecher and Essene, 1990, J Petrol 31, 997). Alteration of plagioclase to Cl-CO3-scapolite is presumed due to metasomatism by CO2-NaCl-H2O fluids (Satish-Kumar and Santosh, 1998, Geol Mag 135, 27). Previous experimental work on CO3-scapolite has focused on reversing the equilibrium 3 CaAl2 Si2 O8 + CaCO3 = Ca4 Al6 Si6 O24 CO3 in either pure CO2 (Goldschmidt and Newton, 1977, Am Mineral 62, 1063) or in CO2-H2O (Huckenholz and Seiberl, 1989 Abs IGC 28, 2.79). These experiments have determined that the anorthite- calcite-scapolite equilibrium is nearly pressure-invariant in P-T space (200 to 1500 MPa) occurring at approximately 790 to 820 °C (Huckenholz and Seiberl, 1989). In this study, a series of experiments, involving the equilibrium 3 Plagioclase(An60) + 0.5 CaCO3 + 0.5 CaSO4 = [(Na,Ca)4[Al3 (Al,Si)3 Si3 O24](Cl, CO3, SO4 )] plus an NaCl brine (10/90, 20/80, 30/70, and 50/50 molar NaCl/H2O) have been done at 500, 1000, and 1500 MPa and 600 to 900 °C. Natural plagioclase and scapolite, along with synthetic calcite and anhydrite, were lightly ground together in equi-molar amounts in ethanol. The mineral mix (10 mg) + NaCl brine (5 mg), or pure H2O (1.5 mg), were loaded into 3 mm diameter/1.3 mm long Pt capsules which were arc-welded shut, folded, and placed horizontally in a CaF2 setup (with graphite oven), such that the thermocouple tip touched the Pt capsule, or placed in a hydrothermal autoclave (600 and 700 °C; 500 MPa) with an internal thermocouple. A series of duplicate experiments for the same mineral mix, at the same P-T conditions, were done utilizing pure H2O as the flux. The H2O-only experiments duplicated the P-T reversals of Huckenholz and Seiberl (1989). In contrast

Effect of ENaC Modulators on Rat Neural Responses to NaCl

PubMed Central

Mummalaneni, Shobha; Qian, Jie; Phan, Tam-Hao T.; Rhyu, Mee-Ra; Heck, Gerard L.; DeSimone, John A.; Lyall, Vijay

2014-01-01

The effects of small molecule ENaC activators N,N,N-trimethyl-2-((4-methyl-2-((4-methyl-1H-indol-3-yl)thio)pentanoyl)oxy)ethanaminium iodide (Compound 1) and N-(2-hydroxyethyl)-4-methyl-2-((4-methyl-1H-indol-3-yl)thio)pentanamide (Compound 2), were tested on the benzamil (Bz)-sensitive NaCl chorda tympani (CT) taste nerve response under open-circuit conditions and under ±60 mV applied lingual voltage-clamp, and compared with the effects of known physiological activators (8-CPT-cAMP, BAPTA-AM, and alkaline pH), and an inhibitor (ionomycin+Ca2+) of ENaC. The NaCl CT response was enhanced at −60 mV and suppressed at +60 mV. In every case the CT response (r) versus voltage (V) curve was linear. All ENaC activators increased the open-circuit response (ro) and the voltage sensitivity (κ, negative of the slope of the r versus V curve) and ionomycin+Ca2+ decreased ro and κ to zero. Compound 1 and Compound 2 expressed a sigmoidal-saturating function of concentration (0.25–1 mM) with a half-maximal response concentration (k) of 0.49 and 1.05 mM, respectively. Following treatment with 1 mM Compound 1, 8-CPT-cAMP, BAPTA-AM and pH 10.3, the Bz-sensitive NaCl CT response to 100 mM NaCl was enhanced and was equivalent to the Bz-sensitive CT response to 300 mM NaCl. Plots of κ versus ro in the absence and presence of the activators or the inhibitor were linear, suggesting that changes in the affinity of Na+ for ENaC under different conditions are fully compensated by changes in the apical membrane potential difference, and that the observed changes in the Bz-sensitive NaCl CT response arise exclusively from changes in the maximum CT response (rm). The results further suggest that the agonists enhance and ionomycin+Ca2+ decreases ENaC function by increasing or decreasing the rate of release of Na+ from its ENaC binding site to the receptor cell cytosol, respectively. Irrespective of agonist type, the Bz-sensitive NaCl CT response demonstrated a maximum response enhancement

cAMP-dependent and cholinergic regulation of the electrogenic intestinal/pancreatic Na+/HCO3- cotransporter pNBC1 in human embryonic kidney (HEK293) cells.

PubMed

Bachmann, Oliver; Franke, Kristin; Yu, Haoyang; Riederer, Brigitte; Li, Hong C; Soleimani, Manoocher; Manns, Michael P; Seidler, Ursula

2008-12-22

The renal (kNBC1) and intestinal (pNBC1) electrogenic Na+/HCO3- cotransporter variants differ in their primary structure, transport direction, and response to secretagogues. Previous studies have suggested that regulatory differences between the two subtypes can be partially explained by unique consensus phosphorylation sites included in the pNBC1, but not the kNBC1 sequence. After having shown activation of NBC by carbachol and forskolin in murine colon, we now investigated these pathways in HEK293 cells transiently expressing a GFP-tagged pNBC1 construct. Na+- and HCO3-dependent pHi recovery from an acid load (measured with BCECF) was enhanced by 5-fold in GFP-positive cells compared to the control cells in the presence of CO2/HCO3-. Forskolin (10(-5) M) had no effect in untransfected cells, but inhibited the pHi recovery in cells expressing pNBC1 by 62%. After preincubation with carbachol (10(-4) M), the pHi recovery was enhanced to the same degree both in transfected and untransfected cells, indicating activation of endogenous alkalizing ion transporters. Acid-activated Na+/HCO3- cotransport via pNBC1 expressed in renal cells is thus inhibited by cAMP and not affected by cholinergic stimulation, as opposed to the findings in native intestinal tissue. Regulation of pNBC1 by secretagogues appears to be not solely dependent on its primary structure, but also on properties of the cell type in which it is expressed.

Mediator of DNA damage checkpoint 1 (MDC1) contributes to high NaCl-induced activation of the osmoprotective transcription factor TonEBP/OREBP.

PubMed

Kunin, Margarita; Dmitrieva, Natalia I; Gallazzini, Morgan; Shen, Rong-Fong; Wang, Guanghui; Burg, Maurice B; Ferraris, Joan D

2010-08-11

Hypertonicity, such as induced by high NaCl, increases the activity of the transcription factor TonEBP/OREBP whose target genes increase osmoprotective organic osmolytes and heat shock proteins. We used mass spectrometry to analyze proteins that coimmunoprecipitate with TonEBP/OREBP in order to identify ones that might contribute to its high NaCl-induced activation. We identified 20 unique peptides from Mediator of DNA Damage Checkpoint 1 (MDC1) with high probability. The identification was confirmed by Western analysis. We used small interfering RNA knockdown of MDC1 to characterize its osmotic function. Knocking down MDC1 reduces high NaCl-induced increases in TonEBP/OREBP transcriptional and transactivating activity, but has no significant effect on its nuclear localization. We confirm six previously known phosphorylation sites in MDC1, but do not find evidence that high NaCl increases phosphorylation of MDC1. It is suggestive that MDC1 acts as a DNA damage response protein since hypertonicity reversibly increases DNA breaks, and other DNA damage response proteins, like ATM, also associate with TonEBP/OREBP and contribute to its activation by hypertonicity. MDC1 associates with TonEBP/OREBP and contributes to high NaCl-induced increase of that factor's transcriptional activity.

Phase Changes of Monosulfoaluminate in NaCl Aqueous Solution

DOE PAGES

Yoon, Seyoon; Ha, Juyoung; Chae, Sejung Rosie; ...

2016-05-21

Monosulfoaluminate (Ca 4Al 2(SO 4)(OH) 12∙6H 2O) plays an important role in anion binding in Portland cement by exchanging its original interlayer ions (SO 4 2- and OH -) with chloride ions. In this study, scanning transmission X-ray microscope (STXM), X-ray absorption near edge structure (XANES) spectroscopy, and X-ray diffraction (XRD) were used to investigate the phase change of monosulfoaluminate due to its interaction with chloride ions. Pure monosulfoaluminate was synthesized and its powder samples were suspended in 0, 0.1, 1, 3, and 5 M NaCl solutions for seven days. At low chloride concentrations, a partial dissolution of monosulfoaluminate formedmore » ettringite, while, with increasing chloride content, the dissolution process was suppressed. As the NaCl concentration increased, the dominant mechanism of the phase change became ion exchange, resulting in direct phase transformation from monosulfoaluminate to Kuzel’s salt or Friedel’s salt. The phase assemblages of the NaCl-reacted samples were explored using thermodynamic calculations and least-square linear combination (LC) fitting of measured XANES spectra. A comprehensive description of the phase change and its dominant mechanism are discussed.« less

Spontaneous nano-gap formation in Ag film using NaCl sacrificial layer for Raman enhancement

NASA Astrophysics Data System (ADS)

Min, Kyungchan; Jeon, Wook Jin; Kim, Youngho; Choi, Jae-Young; Yu, Hak Ki

2018-03-01

We report the method of fabrication of nano-gaps (known as hot spots) in Ag thin film using a sodium chloride (NaCl) sacrificial layer for Raman enhancement. The Ag thin film (20-50 nm) on the NaCl sacrificial layer undergoes an interfacial reaction due to the AgCl formed at the interface during water molecule intercalation. The intercalated water molecules can dissolve the NaCl molecules at interfaces and form the ionic state of Na+ and Cl-, promoting the AgCl formation. The Ag atoms can migrate by the driving force of this interfacial reaction, resulting in the formation of nano-size gaps in the film. The surface-enhanced Raman scattering activity of Ag films with nano-size gaps has been investigated using Raman reporter molecules, Rhodamine 6G (R6G).

MAPK-mediated regulation of growth and essential oil composition in a salt-tolerant peppermint (Mentha piperita L.) under NaCl stress.

PubMed

Li, Zhe; Wang, Wenwen; Li, Guilong; Guo, Kai; Harvey, Paul; Chen, Quan; Zhao, Zhongjuan; Wei, Yanli; Li, Jishun; Yang, Hetong

2016-11-01

Peppermint (Mentha × piperita L.) is an important and commonly used flavoring agent worldwide, and salinity is a major stress that limits plant growth and reduces crop productivity. This work demonstrated the metabolic responses of essential oil production including the yield and component composition, gene expression, enzyme activity, and protein activation in a salt-tolerant peppermint Keyuan-1 with respect to NaCl stress. Our results showed that Keyuan-1 maintained normal growth and kept higher yield and content of essential oils under NaCl stress than wild-type (WT) peppermint.Gas chromatography-mass spectrometry (GC-MS) and qPCR results showed that compared to WT seedlings, a 150-mM NaCl stress exerted no obvious changes in essential oil composition, transcriptional level of enzymes related to essential oil metabolism, and activity of pulegone reductase (Pr) in Keyuan-1 peppermint which preserved the higher amount of menthol and menthone as well as the lower content of menthofuran upon the 150-mM NaCl stress. Furthermore, it was noticed that a mitogen-activated protein kinase (MAPK) protein exhibited a time-dependent activation in the Keyuan-1 peppermint and primarily involved in the modulation of the essential oil metabolism in the transcript and enzyme levels during the 12-day treatment of 150 mM NaCl. In all, our data elucidated the effect of NaCl on metabolic responses of essential oil production, and demonstrated the MAPK-dependent regulation mechanism of essential oil biosynthesis in the salt-tolerant peppermint, providing scientific basis for the economic and ecological utilization of peppermint in saline land.

Hot-corrosion of AISI 1020 steel in a molten NaCl/Na2SO4 eutectic at 700°C

NASA Astrophysics Data System (ADS)

Badaruddin, Mohammad; Risano, Ahmad Yudi Eka; Wardono, Herry; Asmi, Dwi

2017-01-01

Hot-corrosion behavior and morphological development of AISI 1020 steel with 2 mg cm-2 mixtures of various NaCl/Na2SO4 ratios at 700°C were investigated by means of weight gain measurements, Optical Microscope (OM), X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDS). The weight gain kinetics of the steel with mixtures of salt deposits display a rapid growth rates, compared with the weight gain kinetics of AISI 1020 steel without salt deposit in dry air oxidation, and follow a steady-state parabolic law for 49 h. Chloridation and sulfidation produced by a molten NaCl/Na2SO4 on the steel induced hot-corrosion mechanism attack, and are responsible for the formation of thicker scale. The most severe corrosion takes place with the 70 wt.% NaCl mixtures in Na2SO4. The typical Fe2O3 whisker growth in outer part scale was attributed to the FeCl3 volatilization. The formation of FeS in the innermost scale is more pronounced as the content of Na2SO4 in the mixture is increased.

A possible NaCl pathway in the bioregenerative human life support system

NASA Astrophysics Data System (ADS)

Polonskiy, V. I.; Gribovskaya, I. V.

One of the ways to involve NaCl in the mass exchange of the bioregenerative human life support system (BLSS) is to grow some vegetables and leafy greens that can accumulate sodium chloride at high concentrations in their edible biomass. Lettuce, celery cabbage, chard, dill and radish plants were grown hydroponically in Knop's nutrient solution. In the first series of experiments, at the end of the growth period the plants were grown on solutions containing 2-14 g/L of NaCl for 1-5 days. It was found that the amount of sodium in edible biomass of the plants increased with NaCl concentration in the solution and with the time plants were irrigated with that solution. The content of NaCl in the biomass of leaves and edible roots was considerable—up to 10% dry matter. At the same time, the amount of water in the leaves decreased and productivity of the treatment plants was 14-28% lower than that of the control ones, grown on Knop's solution. The treatment plants contained less than half of the amount of nitrates recorded in the control ones. Expert evaluation showed that the taste of the vegetables and leafy greens of the treatment group were not inferior to the taste of the control plants. In the second series of experiments, prior to being grown on the NaCl solution, the plants were irrigated with water for 2, 4 or 6 days. It was found that lower salt status of the plants was not favorable for increased salt accumulation in their biomass. If a human consumes 30 g salad vegetables and follows a low-sodium diet (3 g/d of table salt), it may be feasible to recycle NaCl in the BLSS using vegetables and leafy greens.

First principles molecular dynamics of molten NaCl

NASA Astrophysics Data System (ADS)

Galamba, N.; Costa Cabral, B. J.

2007-03-01

First principles Hellmann-Feynman molecular dynamics (HFMD) results for molten NaCl at a single state point are reported. The effect of induction forces on the structure and dynamics of the system is studied by comparison of the partial radial distribution functions and the velocity and force autocorrelation functions with those calculated from classical MD based on rigid-ion and shell-model potentials. The first principles results reproduce the main structural features of the molten salt observed experimentally, whereas they are incorrectly described by both rigid-ion and shell-model potentials. Moreover, HFMD Green-Kubo self-diffusion coefficients are in closer agreement with experimental data than those predicted by classical MD. A comprehensive discussion of MD results for molten NaCl based on different ab initio parametrized polarizable interionic potentials is also given.

Differential tolerance of 3 self-rooted Citrus limon cultivars to NaCl stress.

PubMed

Tsabarducas, V; Chatzistathis, T; Therios, I; Koukourikou-Petridou, M; Tananaki, C

2015-12-01

One-year-old self-rooted cuttings of three Citrus limon cultivars (Nouvel Athos, Lisbon, Maglini) were grown in 1 L black plastic bags, containing a mixture of sand: perlite (1:1), in order to investigate: i) if genotypic differences to salt stress existed, ii) if KNO3 can alleviate salinity stress, iii) the role of carbohydrates (such as the sugars fructose, glucose and sucrose) and proline as possible osmoregulators in C. limon osmoprotection, and iv) if genotypic differences to salt stress tolerance exist among the 3 studied cultivars. The experiment included 3 treatments: i) control (C), i.e. 25% modified Hoagland (No2) solution (MHS)-NaCl, ii) T1, 25% MHS+80 mM NaCl, iii) T2, 25% MHS+80 mM NaCl+5 mM KNO3. Plant growth was negatively affected by high NaCl (T1); the highest Cl and Na quantities have been absorbed by Lisbon, while the lowest ones by Maglini. Salt stress reduced macronutrient and Zn concentrations, as well as the total carbohydrate concentration, and increased peroxidase (POD) activity and chlorophyll fluorescence in the leaves of the 3 C. limon cultivars studied; five mM KNO3 application alleviated the harmful effect of salt stress on leaf total carbohydrate concentration and leaf N and K concentrations. Sucrose was dramatically reduced in all the three genotypes studied, while leaf fructose concentration was significantly increased in Nouvel Nouvel Nouvel Athos and Maglini under salt stress. Leaf proline concentration of Maglini was significantly decreased by the high NaCl concentration, while Nouvel Athos and Lisbon had high proline concentration in their leaves. In conclusion, from the significantly decreased levels of proline for Maglini, together with the greatest reduction of the ratio Fv/Fm and the least enhancement of POD activity-compared to the other two cultivars-it can be concluded that Maglini was more susceptible to salinity, and should not be preferred for cultivation under NaCl stress. Finally, rich KNO3 application

Low-field NMR determination of water distribution in meat batters with NaCl and polyphosphate addition.

PubMed

Shao, Jun-Hua; Deng, Ya-Min; Jia, Na; Li, Ru-Ren; Cao, Jin-Xuan; Liu, Deng-Yong; Li, Jian-Rong

2016-06-01

The objective was to elucidate the influence of NaCl and polyphosphates in the stage of protein swelling on the water-holding capacity (WHC) of meat batter. The meat batters were formulated with salt in different ways by adding established amounts of only NaCl, only polyphosphates, jointly adding NaCl and polyphosphates, and a control without any salt. An increase (p<0.05) in water retention was found when a combination of NaCl and polyphosphates was used. A high textural parameter was observed in the two treatments with NaCl, but not in the group with only polyphosphate. For the polyphosphate group, T22 was lower (p<0.05) than in the other three before heating; however, after heating, T21 and T22 were both significantly decreased, and a new component emerged, T23, which was significantly lower than the others. For the NaCl treatment, heated or not, T22 was always the highest. It was revealed that NaCl had affected the WHC by increasing the mobility and distribution of water, particularly with polyphosphate, but polyphosphate could not be an equal substitute for NaCl given its resulting lowest textural properties and poor microstructure. By presenting different hydration states in the protein swelling stage, the meat batter qualities were differentiated. Copyright © 2016 Elsevier Ltd. All rights reserved.

The Na+-Taurocholate Cotransporting Polypeptide Traffics with the Epidermal Growth Factor Receptor

PubMed Central

Wang, Xintao; Wang, Pijun; Wang, Wenjun; Murray, John W.; Wolkoff, Allan W.

2015-01-01

Na+-taurocholate cotransporting polypeptide (ntcp) mediates uptake of bile acids as well as serving as the receptor for hepatitis B virus in human liver. Previous studies showed that ntcp traffics on microtubules between the cell surface and endocytic vesicles. Specific inhibition of protein kinase C (PKC)ζ resulted in loss of microtubule-based motility of these vesicles in vitro and in living cells. The aim of the present study was to characterize the PKCζ target. Incubation of ntcp-containing endocytic vesicles with γ-32P-ATP revealed a 180 kDa phosphoglycoprotein that was identified as the EGF receptor (EGFR). Surface biotinylation of HuH7 cells expressing GFP-ntcp revealed substantially reduced trafficking of ntcp to the cell surface with EGFR knockdown. Microtubule-based motility of ntcp-containing endocytic vesicles was also significantly reduced when they were not associated with EGFR. Ntcp was also found to undergo cellular redistribution upon stimulation of cells with EGF, consistent with a model in which ntcp and EGF-EGFR internalize into common endocytic vesicles from which they segregate, trafficking EGF-EGFR to lysosomes and recycling ntcp to the plasma membrane. EGF regulation of ntcp trafficking may play a heretofore unanticipated role in subcellular targeting of ntcp ligands such as hepatitis B. PMID:26650232

Infrared Spectroscopy of NaCl(CH3OH)n Complexes in Helium Nanodroplets.

PubMed

Sadoon, Ahmed M; Sarma, Gautam; Cunningham, Ethan M; Tandy, Jon; Hanson-Heine, Magnus W D; Besley, Nicholas A; Yang, Shengfu; Ellis, Andrew M

2016-10-10

Infrared (IR) spectra of complexes between NaCl and methanol have been recorded for the first time. These complexes were formed in liquid helium nanodroplets by consecutive pick-up of NaCl and CH 3 OH molecules. For the smallest NaCl(CH 3 OH) n , complexes where n = 1-3, the IR data suggest that the lowest-energy isomer is the primary product in each case. The predominant contribution to the binding comes from ionic hydrogen bonds between the OH in each methanol molecule and the chloride ion in the NaCl, as established by the large red shift of the OH stretching bands compared with the isolated CH 3 OH molecule. For n ≥ 4, there is a dramatic shift from discrete vibrational bands to very broad absorption envelopes, suggesting a profound change in the structural landscape and, in particular, access to multiple low-energy isomers.

Critical behavior of dilute NaCl in H2O

USGS Publications Warehouse

Pitzer, Kenneth S.; Bischoff, J.L.; Rosenbauer, R.J.

1987-01-01

The compositions of the saturated vapor and liquid phases are measured for the system NaCl-H2O at 380??C, which is close to the critical point of pure water. The shape of the phase equilibrium curve is classical, which confirms a conclusion reached earlier on the basis of less accurate data. This implies that the long-range forces introduced by the NaCl suppress the non-classical effects present in pure H2O. An empirical equation of a classical type fits these data. ?? 1987.

Activation of AMPK reduces the co-transporter activity of NKCC1.

PubMed

Fraser, Scott A; Davies, Matthew; Katerelos, Marina; Gleich, Kurt; Choy, Suet-Wan; Steel, Rohan; Galic, Sandra; Mount, Peter F; Kemp, Bruce E; Power, David A

2014-01-01

The co-transporter activity of Na(+)-K(+)-2Cl(-) 1 (NKCC1) is dependent on phosphorylation. In this study we show the energy-sensing kinase AMPK inhibits NKCC1 activity. Three separate AMPK activators (AICAR, Phenformin and A-769662) inhibited NKCC1 flux in a variety of nucleated cells. Treatment with A-769662 resulted in a reduction of NKCC1(T212/T217) phosphorylation, and this was reversed by treatment with the non-selective AMPK inhibitor Compound C. AMPK dependence was confirmed by treatment of AMPK null mouse embryonic fibroblasts, where A-769662 had no effect on NKCC1 mediated transport. AMPK was found to directly phosphorylate a recombinant human-NKCC1 N-terminal fragment (1-293) with the phosphorylated site identified as S77. Mutation of Serine 77 to Alanine partially prevented the inhibitory effect of A-769662 on NKCC1 activity. In conclusion, AMPK can act to reduce NKCC1-mediated transport. While the exact mechanism is still unclear there is evidence for both a direct effect on phosphorylation of S77 and reduced phosphorylation of T212/217.

The ERK pathway regulates Na(+)-HCO(3)(-) cotransport activity in adult rat cardiomyocytes.

PubMed

Baetz, Delphine; Haworth, Robert S; Avkiran, Metin; Feuvray, Danielle

2002-11-01

The sarcolemmal Na(+)-HCO cotransporter (NBC) is stimulated by intracellular acidification and acts as an acid extruder. We examined the role of the ERK pathway of the MAPK cascade as a potential mediator of NBC activation by intracellular acidification in the presence and absence of angiotensin II (ANG II) in adult rat ventricular myocytes. Intracellular pH (pH(i)) was recorded with the use of seminaphthorhodafluor-1. The NH method was used to induce an intracellular acid load. NBC activation was significantly decreased with the ERK inhibitors PD-98059 and U-0126. NBC activity after acidification was increased in the presence of ANG II (pH(i) range of 6.75-7.00). ANG II plus PD-123319 (AT(2) antagonist) still increased NBC activity, whereas ANG II plus losartan (AT(1) antagonist) did not affect it. ERK phosphorylation (measured by immunoblot analysis) during intracellular acidification was increased by ANG II, an effect that was abolished by losartan and U-0126. In conclusion, the MAPK(ERK)-dependent pathway facilitates the rate of pH(i) recovery from acid load through NBC activity and is involved in the AT(1) receptor-mediated stimulation of such activity by ANG II.

Five ab initio potential energy and dipole moment surfaces for hydrated NaCl and NaF. I. Two-body interactions.

PubMed

Wang, Yimin; Bowman, Joel M; Kamarchik, Eugene

2016-03-21

We report full-dimensional, ab initio-based potentials and dipole moment surfaces for NaCl, NaF, Na(+)H2O, F(-)H2O, and Cl(-)H2O. The NaCl and NaF potentials are diabatic ones that dissociate to ions. These are obtained using spline fits to CCSD(T)/aug-cc-pV5Z energies. In addition, non-linear least square fits using the Born-Mayer-Huggins potential are presented, providing accurate parameters based strictly on the current ab initio energies. The long-range behavior of the NaCl and NaF potentials is shown to go, as expected, accurately to the point-charge Coulomb interaction. The three ion-H2O potentials are permutationally invariant fits to roughly 20,000 coupled cluster CCSD(T) energies (awCVTZ basis for Na(+) and aVTZ basis for Cl(-) and F(-)), over a large range of distances and H2O intramolecular configurations. These potentials are switched accurately in the long range to the analytical ion-dipole interactions, to improve computational efficiency. Dipole moment surfaces are fits to MP2 data; for the ion-ion cases, these are well described in the intermediate- and long-range by the simple point-charge expression. The performance of these new fits is examined by direct comparison to additional ab initio energies and dipole moments along various cuts. Equilibrium structures, harmonic frequencies, and electronic dissociation energies are also reported and compared to direct ab initio results. These indicate the high fidelity of the new PESs.

Determination of oxidative stress in wheat leaves as influenced by boron toxicity and NaCl stress.

PubMed

Masood, Sajid; Saleh, Livia; Witzel, Katja; Plieth, Christoph; Mühling, Karl H

2012-07-01

Boron (B) toxicity symptoms are visible in the form of necrotic spots and may worsen the oxidative stress caused by salinity. Hence, the interactive effects of combined salinity and B toxicity stress on antioxidative activities (TAC, LUPO, SOSA, CAT, and GR) were investigated by novel luminescence assays and standard photometric procedures. Wheat plants grown under hydroponic conditions were treated with 2.5 μM H₃BO₃ (control), 75 mM NaCl, 200 μM H₃BO₃, or 75 mM NaCl + 200 μM H₃BO₃, and analysed 6 weeks after germination. Shoot fresh weight (FW), shoot dry weight (DW), and relative water content (RWC) were significantly reduced, whereas the antioxidative activity of all enzymes was increased under salinity compared with the control. High B application led to necrotic leaf spots but did not influence growth parameters. Following NaCl + B treatment, shoot DW, RWC, SOSA, GR, and CAT activities remained the same compared with NaCl alone, whereas the TAC and LUPO activities were increased under the combined stress compared with NaCl alone. However, shoot FW was significantly reduced under NaCl + B compared with NaCl alone, as an additive effect of combined stress. Thus, we found an adjustment of antioxidative enzyme activity to the interactive effects of NaCl and high B. The stress factor "salt" mainly produced more oxidative stress than that of the factor "high B". Furthermore, addition of higher B in the presence of NaCl increases TAC and LUPO demonstrating that increased LUPO activity is an important physiological response in wheat plants against multiple stresses. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

Effects of dilute aqueous NaCl solution on caffeine aggregation

NASA Astrophysics Data System (ADS)

Sharma, Bhanita; Paul, Sandip

2013-11-01

The effect of salt concentration on association properties of caffeine molecule was investigated by employing molecular dynamics simulations in isothermal-isobaric ensemble of eight caffeine molecules in pure water and three different salt (NaCl) concentrations, at 300 K temperature and 1 atm pressure. The concentration of caffeine was taken almost at the solubility limit. With increasing salt concentration, we observe enhancement of first peak height and appearance of a second peak in the caffeine-caffeine distribution function. Furthermore, our calculated solvent accessible area values and cluster structure analyses suggest formation of higher order caffeine cluster on addition of salt. The calculated hydrogen bond properties reveal that there is a modest decrease in the average number of water-caffeine hydrogen bonds on addition of NaCl salt. Also observed are: (i) decrease in probability of salt contact ion pair as well as decrease in the solvent separated ion pair formation with increasing salt concentration, (ii) a modest second shell collapse in the water structure, and (iii) dehydration of hydrophobic atomic sites of caffeine on addition of NaCl.

Effects of dilute aqueous NaCl solution on caffeine aggregation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sharma, Bhanita; Paul, Sandip, E-mail: sandipp@iitg.ernet.in

The effect of salt concentration on association properties of caffeine molecule was investigated by employing molecular dynamics simulations in isothermal-isobaric ensemble of eight caffeine molecules in pure water and three different salt (NaCl) concentrations, at 300 K temperature and 1 atm pressure. The concentration of caffeine was taken almost at the solubility limit. With increasing salt concentration, we observe enhancement of first peak height and appearance of a second peak in the caffeine-caffeine distribution function. Furthermore, our calculated solvent accessible area values and cluster structure analyses suggest formation of higher order caffeine cluster on addition of salt. The calculated hydrogenmore » bond properties reveal that there is a modest decrease in the average number of water-caffeine hydrogen bonds on addition of NaCl salt. Also observed are: (i) decrease in probability of salt contact ion pair as well as decrease in the solvent separated ion pair formation with increasing salt concentration, (ii) a modest second shell collapse in the water structure, and (iii) dehydration of hydrophobic atomic sites of caffeine on addition of NaCl.« less

Aspects of Salt Tolerance in a NaCl-Selected Stable Cell Line of Citrus sinensis1

PubMed Central

Ben-Hayyim, Gozal; Kochba, Joshua

1983-01-01

A NaCl-tolerant cell line which was selected from ovular callus of `Shamouti' orange (Citrus sinensis L. Osbeck) proved to be a true cell line variant. This conclusion is based on the following observations. (a) Cells which have been removed from the selection pressure for at least four passages retain the same NaCl tolerance as do cells which are kept constantly on 0.2 molar NaCl. (b) Na+ and Cl− uptake are considerably lower in salt-tolerant cells (R-10) than in salt-sensitive cells (L-5) at a given external NaCl concentration. (c) Growth of salt-tolerant cells is markedly suppressed upon replacement of NaCl by KCl, whereas the growth of salt-sensitive cells is only slightly affected. Accumulation of K+ and Cl− accompanies the inhibition of growth. Experiments carried out with sodium and potassium sulfate suggest that the toxic effect is due to the accumulated Cl−. (d) Removal of Ca2+ from the growth medium severely inhibits the growth of salt-tolerant cells in the presence of NaCl, while it has a minor effect on growth of salt-sensitive cells in the presence of NaCl. (e) Electron micrographs show that the salt-tolerant cells have very big vacuoles when exposed to salt, while the size of the vacuoles of the salt-sensitive cells does not change. Images Fig. 3 PMID:16663067

Characterization of CuCl quantum dots grown in NaCl single crystals via optical measurements, X-ray diffraction, and transmission electron microscopy

NASA Astrophysics Data System (ADS)

Miyajima, Kensuke; Akatsu, Tatsuro; Itoh, Ken

2018-05-01

We evaluated the crystal size, shape, and alignment of the lattice planes of CuCl quantum dots (QDs) embedded in NaCl single crystals by optical measurements, X-ray diffraction (XRD) patterns, and transmission electron microscopy (TEM). We obtained, for the first time, an XRD pattern and TEM images for CuCl QDs in NaCl crystals. The XRD pattern showed that the lattice planes of the CuCl QDs were parallel to those of the NaCl crystals. In addition, the size of the QDs was estimated from the diffraction width. It was apparent from the TEM images that almost all CuCl QDs were polygonal, although some cubic QDs were present. The mean size and size distribution of the QDs were also obtained. The dot size obtained from optical measurements, XRD, and TEM image were almost consistent. Our new findings can help to reveal the growth mechanism of semiconductor QDs embedded in a crystallite matrix. In addition, this work will play an important role in progressing the study of optical phenomena originating from assembled semiconductor QDs.

Effects of exogenous salinity (NaCl) gradient on Cd release in acidified contaminated brown soil

NASA Astrophysics Data System (ADS)

Zhang, Lina; Rong, Yong; Mao, Li; Gao, Zhiyuan; Liu, Xiaoyu; Dong, Zhicheng

2018-02-01

Taking acidified Cd contaminated brown soil in Yantai as the research object, based on different exogenous salinity (NaCl) gradient (0%, 0.3%, 0.6%, 0.9%, 1.5%, 2% and 5%), indoor simulation experiments of Cd release were carried out after field investigation. Results showed that there was a significantly positive relation (r>0.90) between Cd release concentration/amount/ratio and exogenous salt (NaCl). Besides, the more exogenous salt (NaCl) was added; maximum release concentration/amount of Cd appeared the earlier. It was found that exogenous salt (NaCl) addition could obviously promote Cd release from acidified Cd contaminated brown soil. It was believed that this could be mainly due to the cation exchange between Cd2+ and Na+, together with the dissociation and/or complexation between Cl- and Cd2+. In addition, available adsorption sites reduction by exchange base in soil causing Cd changed from solid state to soil solution was also a probable reason.

Kinetics Study on the Effect of NaCl on the CaSO4 Dissolution Behavior

NASA Astrophysics Data System (ADS)

Song, Jingyao; Shi, Peiyang; Wang, Yeguang; Jiang, Maofa

2018-01-01

The study of the dissolution kinetics of CaSO4 is essential for the control of the dissolution and recrystallization behavior of CaSO4. In this work, the kinetic behavior of CaSO4 dissolved in NaCl solution was investigated by means of conductivity meter. The results show that with the increase of concentration of NaCl, the temperature rise and the time prolonged, the dissolution rate of dihydrate CaSO4 gradually increases, and the dissolved apparent activation energy is gradually decreased. When the NaCl concentration is 1.8%, the dissolution kinetic equation is 1-(1-α) 1/3=5.46*10-4exp (-9147/RT) t; When the NaCl concentration is 3.0%, the dissolution kinetic equation is 1-(1-α) 1/3=2.81×10-4 exp (-6753/RT)t; When the NaCl concentration is 3.6%, the dissolution kinetic equation is 1-(1-α) 1/3=3.07×l0-4exp(-6103/RT)t.

Five ab initio potential energy and dipole moment surfaces for hydrated NaCl and NaF. I. Two-body interactions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Yimin, E-mail: yimin.wang@emory.edu; Bowman, Joel M., E-mail: jmbowma@emory.edu; Kamarchik, Eugene, E-mail: eugene.kamarchik@gmail.com

2016-03-21

We report full-dimensional, ab initio-based potentials and dipole moment surfaces for NaCl, NaF, Na{sup +}H{sub 2}O, F{sup −}H{sub 2}O, and Cl{sup −}H{sub 2}O. The NaCl and NaF potentials are diabatic ones that dissociate to ions. These are obtained using spline fits to CCSD(T)/aug-cc-pV5Z energies. In addition, non-linear least square fits using the Born-Mayer-Huggins potential are presented, providing accurate parameters based strictly on the current ab initio energies. The long-range behavior of the NaCl and NaF potentials is shown to go, as expected, accurately to the point-charge Coulomb interaction. The three ion-H{sub 2}O potentials are permutationally invariant fits to roughly 20 000more » coupled cluster CCSD(T) energies (awCVTZ basis for Na{sup +} and aVTZ basis for Cl{sup −} and F{sup −}), over a large range of distances and H{sub 2}O intramolecular configurations. These potentials are switched accurately in the long range to the analytical ion-dipole interactions, to improve computational efficiency. Dipole moment surfaces are fits to MP2 data; for the ion-ion cases, these are well described in the intermediate- and long-range by the simple point-charge expression. The performance of these new fits is examined by direct comparison to additional ab initio energies and dipole moments along various cuts. Equilibrium structures, harmonic frequencies, and electronic dissociation energies are also reported and compared to direct ab initio results. These indicate the high fidelity of the new PESs.« less

Central endogenous angiotensin-(1-7) protects against aldosterone/NaCl-induced hypertension in female rats.

PubMed

Xue, Baojian; Zhang, Zhongming; Johnson, Ralph F; Guo, Fang; Hay, Meredith; Johnson, Alan Kim

2013-09-01

In comparison to male rodents, females are protected against angiotensin (ANG) II- and aldosterone (Aldo)-induced hypertension. However, the mechanisms underlying this protective effect are not well understood. ANG-(1-7) is formed from ANG II by angiotensin-converting enzyme 2 (ACE2) and has an antihypertensive effect in the central nervous system (CNS). The present study tested the hypothesis that central ANG-(1-7) plays an important protective role in attenuating the development of Aldo/NaCl-hypertension in female rats. Systemic infusion of Aldo into intact female rats with 1% NaCl as their sole drinking fluid resulted in a slight increase in blood pressure (BP). Intracerebroventricular (icv) infusion of A-779, an ANG-(1-7) receptor (Mas-R) antagonist, significantly augmented the pressor effects of Aldo/NaCl. In contrast, systemic Aldo/NaCl induced a significant increase in BP in ovariectomized (OVX) female rats, and central infusion of ANG-(1-7) significantly attenuated this Aldo/NaCl pressor effect. The inhibitory effect of ANG-(1-7) on the Aldo/NaCl pressor effect was abolished by concurrent infusion of A-779. RT-PCR analyses showed that there was a corresponding change in mRNA expression of several renin-angiotensin system components, estrogen receptors and an NADPH oxidase subunit in the lamina terminalis. Taken together these results suggest that female sex hormones regulate an antihypertensive axis of the brain renin-angiotensin system involving ACE2/ANG-(1-7)/Mas-R that plays an important counterregulatory role in protecting against the development of Aldo/NaCl-induced hypertension.

Potassium Supplementation Prevents Sodium Chloride Cotransporter Stimulation During Angiotensin II Hypertension.

PubMed

Veiras, Luciana C; Han, Jiyang; Ralph, Donna L; McDonough, Alicia A

2016-10-01

Angiotensin II (AngII) hypertension increases distal tubule Na-Cl cotransporter (NCC) abundance and phosphorylation (NCCp), as well as epithelial Na(+) channel abundance and activating cleavage. Acutely raising plasma [K(+)] by infusion or ingestion provokes a rapid decrease in NCCp that drives a compensatory kaliuresis. The first aim tested whether acutely raising plasma [K(+)] with a single 3-hour 2% potassium meal would lower NCCp in Sprague-Dawley rats after 14 days of AngII (400 ng/kg per minute). The potassium-rich meal neither decreased NCCp nor increased K(+) excretion. AngII-infused rats exhibited lower plasma [K(+)] versus controls (3.6±0.2 versus 4.5±0.1 mmol/L; P<0.05), suggesting that AngII-mediated epithelial Na(+) channel activation provokes K(+) depletion. The second aim tested whether doubling dietary potassium intake from 1% (A1K) to 2% (A2K) would prevent K(+) depletion during AngII infusion and, thus, prevent NCC accumulation. A2K-fed rats exhibited normal plasma [K(+)] and 2-fold higher K(+) excretion and plasma [aldosterone] versus A1K. In A1K rats, NCC, NCCpS71, and NCCpT53 abundance increased 1.5- to 3-fold versus controls (P<0.05). The rise in NCC and NCCp abundance was prevented in the A2K rats, yet blood pressure did not significantly decrease. Epithelial Na(+) channel subunit abundance and cleavage increased 1.5- to 3-fold in both A1K and A2K; ROMK (renal outer medulla K(+) channel abundance) abundance was unaffected by AngII or dietary K(+) In summary, the accumulation and phosphorylation of NCC seen during chronic AngII infusion hypertension is likely secondary to potassium deficiency driven by epithelial Na(+) channel stimulation. © 2016 American Heart Association, Inc.

Effects of high NaCl diet on arterial pressure in Sprague-Dawley rats with hepatic and sinoaortic denervation.

PubMed

Gao, Shuang; Tanaka, Kunihiko; Gotoh, Taro M; Morita, Hironobu

2005-08-01

The Na(+) receptor that exists in the hepatoportal region plays an important role in postprandial natriuresis and the regulation of Na(+) balance during NaCl load. Thus it would be considered that a dysfunction of the hepatic Na(+) receptor might result in the elevation of arterial pressure under a condition of high NaCl diet. To elucidate this hypothesis, arterial pressure was continuously measured during three weeks of high NaCl diet (8% NaCl) in four groups of rats: (i) intact rats, (ii) rats with hepatic denervation (HD), (iii) rats with sinoaortic denervation (SAD), and (iv) rats with SAD+HD. During a 1-week normal NaCl diet period, there was no difference in arterial pressure among the four groups. A high NaCl diet had no influence on arterial pressure in intact or HD rats; however, it significantly increased by 11 +/- 3 mmHg in SAD rats. The addition of HD to SAD had no synergistic effect on arterial pressure; i.e., in SAD+HD rats, mean arterial pressure increased by 13 +/- 1 mmHg. In conclusion, sinoaortic baroreceptor, but not hepatic Na(+) receptor, has a significant role in the long-term regulation of arterial pressure on a high NaCl diet.

Thermodynamic Study of Solid-Liquid Equilibrium in NaCl-NaBr-H2O System at 288.15 K

NASA Astrophysics Data System (ADS)

Li, Dan; Meng, Ling-zong; Deng, Tian-long; Guo, Ya-fei; Fu, Qing-Tao

2018-06-01

The solubility data, composition of the solid solution and refractive indices of the NaCl-NaBr-H2O system at 288.15 K were studied with the isothermal equilibrium dissolution method. The solubility diagram and refractive index diagram of this system were plotted at 288.15 K. The solubility diagram consists of two crystallization zones for solid solution Na(Cl,Br) · 2H2O and Na(Cl,Br), one invariant points cosaturated with two solid solution and two univariant solubility isothermal curves. On the basis of Pitzer and Harvie-Weare (HW) chemical models, the composition equations and solubility equilibrium constant equations of the solid solutions at 288.15 K were acquired using the solubility data, the composition of solid solutions, and binary Pitzer parameters. The solubilities calculated using the new method combining the equations are in good agreement with the experimental data.

Structure and Function of Na+-Symporters with Inverted Repeats

PubMed Central

Abramson, Jeff; Wright, Ernest M.

2009-01-01

Summary Symporters are membrane proteins that couple energy stored in electrochemical potential gradients to drive the cotransport of molecules and ions into cells. Traditionally, proteins are classified into gene families based on sequence homology and functional properties, e.g. the sodium glucose (SLC5 or Sodium Solute Symporter Family, SSS or SSF) and GABA (SLC6 or Neurotransmitter Sodium Symporter Family, NSS or SNF) symporter families [1-4]. Recently, it has been established that four Na+-symporter proteins with unrelated sequences have a common structural core containing an inverted repeat of 5 transmembrane (TM) helices [5-8]. Analysis of these four structures reveals that they reside in different conformations along the transport cycle providing atomic insight into the mechanism of sodium solute cotransport. PMID:19631523

Electrochemistry of Europium(III) Chloride in 3 LiCl – NaCl, 3 LiCl – 2 KCl, LiCl – RbCl, and 3 LiCl – 2 CsCl Eutectics at Various Temperatures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schroll, Cynthia A.; Chatterjee, Sayandev; Levitskaia, Tatiana G.

Here we report the effect of changing the eutectic melt composition on the electrochemical properties of europium(III) chloride under pyroprocessing conditions. The number of electrons transferred, redox potentials and diffusion coefficients were determined using various electrochemical and spectroelectrochemical techniques in four different eutectic mixtures (3 LiCl - NaCl, 3 LiCl - 2 KCl, 3 LiCl - RbCl, and 3 LiCl - 2 CsCl) while varying the temperature of the melt. It was determined that Eu3+ undergoes a one electron reduction to Eu2+ in each melt at all temperatures evaluated. Within all the melts a positive shift in the redox potentialmore » as well as an increase in the diffusion coefficient for Eu3+ was observed as the temperature increased. Also observed was a positive shift in the redox potential and increase in the diffusion coefficient for Eu3+ as the weighted average of the cationic radii for the melt decreased.« less

Electrodeposition of Al-Ta alloys in NaCl-KCl-AlCl3 molten salt containing TaCl5

NASA Astrophysics Data System (ADS)

Sato, Kazuki; Matsushima, Hisayoshi; Ueda, Mikito

2016-12-01

To form Al-Ta alloys for high temperature oxidation resistance components, molten salt electrolysis was carried out in an AlCl3-NaCl-KCl melt containing TaCl5 at 423 K. The voltammogram showed two cathodic waves at 0.45 V and 0.7 V vs. Al/Al(III), which may correspond to reduction from Ta(V) to Ta(III) and from Ta(III) to tantalum metal, respectively. Electrodeposits of Al and Ta were obtained in the range from -0.05 to 0.3 V and the highest concentration of Ta in the electrodeposit was 72 at% at 0.3 V. With increasing Ta content in the alloy, the morphology of the electrodeposits became powdery and the particle size smaller.

Gustatory Plasticity in "C. elegans" Involves Integration of Negative Cues and NaCl Taste Mediated by Serotonin, Dopamine, and Glutamate

ERIC Educational Resources Information Center

Hukema, Renate K.; Rademakers, Suzanne; Jansen, Gert

2008-01-01

While naive "Caenorhabditis elegans" individuals are attracted to 0.1-200 mM NaCl, they become strongly repelled by these NaCl concentrations after prolonged exposure to 100 mM NaCl. We call this behavior gustatory plasticity. Here, we show that "C. elegans" displays avoidance of low NaCl concentrations only when pre-exposure to NaCl is combined…

Melatonin attenuates neuronal apoptosis through up-regulation of K(+) -Cl(-) cotransporter KCC2 expression following traumatic brain injury in rats.

PubMed

Wu, Haijian; Shao, Anwen; Zhao, Mingfei; Chen, Sheng; Yu, Jun; Zhou, Jingyi; Liang, Feng; Shi, Ligen; Dixon, Brandon J; Wang, Zhen; Ling, Chenhan; Hong, Yuan; Zhang, Jianmin

2016-09-01

Traumatic brain injury (TBI) initiates a complex cascade of neurochemical and signaling changes that leads to neuronal apoptosis, which contributes to poor outcomes for patients with TBI. The neuron-specific K(+) -Cl(-) cotransporter-2 (KCC2), the principal Cl(-) extruder in adult neurons, plays an important role in Cl(-) homeostasis and neuronal function. This present study was designed to investigate the expression pattern of KCC2 following TBI and to evaluate whether or not melatonin is able to prevent neuronal apoptosis by modulating KCC2 expression in a Sprague Dawley rat controlled cortical impact model of TBI. The time course study showed decreased mRNA and protein expression of KCC2 in the ipsilateral peri-core parietal cortex after TBI. Double immunofluorescence staining demonstrated that KCC2 is located in the plasma membrane of neurons. In addition, melatonin (10 mg/kg) was injected intraperitoneally at 5 minutes and repeated at 1, 2, 3, and 4 hours after brain trauma, and brain samples were extracted 24 hours after TBI. Compared to the vehicle group, melatonin treatment altered the down-regulation of KCC2 expression in both mRNA and protein levels after TBI. Also, melatonin treatment increased the protein levels of brain-derived neurotrophic factor (BDNF) and phosphorylated extracellular signal-regulated kinase (p-ERK). Simultaneously, melatonin administration ameliorated cortical neuronal apoptosis, reduced brain edema, and attenuated neurological deficits after TBI. In conclusion, our findings suggested that melatonin restores KCC2 expression, inhibits neuronal apoptosis and attenuates secondary brain injury after TBI, partially through activation of BDNF/ERK pathway. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Electrochemical preparation of carbon films with a Mo2C interlayer in LiCl-NaCl-Na2CO3 melts

NASA Astrophysics Data System (ADS)

Ge, Jianbang; Wang, Shuai; Zhang, Feng; Zhang, Long; Jiao, Handong; Zhu, Hongmin; Jiao, Shuqiang

2015-08-01

The electrodeposition of carbon films with a Mo2C interlayer was investigated in LiCl-NaCl-Na2CO3 melts at 900 °C. Cyclic voltammetry was applied to study the electrochemical reaction mechanism on Mo and Pt electrodes, indicating that, two reduction reactions including carbon deposition and carbon monoxide evolution, may take place on the two electrodes simultaneously during the cathodic sweep. Carbon films with a continuous Mo2C interlayer were prepared by constant voltage electrolysis, showing a good adhesion between Mo substrate and carbon films. The carbon films with a Mo2C interlayer were characterized using X-ray diffraction measurement, Raman spectroscopy, scanning electron microscopy and transmission electron microscopy. The results reveal that carbon materials deposited on the electrodes are mainly composed of graphite and carbon diffusion in Mo (or Mo2C) leads to the formation and growth of Mo2C interlayer.

Constrained Surface Complexation Modeling: Rutile in RbCl, NaCl, and NaCF 3SO 3 Media to 250 °C

DOE Office of Scientific and Technical Information (OSTI.GOV)

Machesky, Michael L.; Předota, Milan; Ridley, Moira K.

In this paper, a comprehensive set of molecular-level results, primarily from classical molecular dynamics (CMD) simulations, are used to constrain CD-MUSIC surface complexation model (SCM) parameters describing rutile powder titrations conducted in RbCl, NaCl, and NaTr (Tr = triflate, CF 3SO 3 –) electrolyte media from 25 to 250 °C. Rb + primarily occupies the innermost tetradentate binding site on the rutile (110) surface at all temperatures (25, 150, 250 °C) and negative charge conditions (-0.1 and -0.2 C/m 2) probed via CMD simulations, reflecting the small hydration energy of this large, monovalent cation. Consequently, variable SCM parameters (Stern-layer capacitancemore » values and intrinsic Rb + binding constants) were adjusted relatively easily to satisfactorily match the CMD and titration data. The larger hydration energy of Na + results in a more complex inner-sphere distribution, which shifts from bidentate to tetradentate binding with increasing negative charge and temperature, and this distribution was not matched well for both negative charge conditions, which may reflect limitations in the CMD and/or SCM approaches. Finally, in particular, the CMD axial density profiles for Rb + and Na + reveal that peak binding distances shift toward the surface with increasing negative charge, suggesting that the CD-MUSIC framework may be improved by incorporating CD or Stern-layer capacitance values that vary with charge.« less

Constrained Surface Complexation Modeling: Rutile in RbCl, NaCl, and NaCF 3SO 3 Media to 250 °C

DOE PAGES

Machesky, Michael L.; Předota, Milan; Ridley, Moira K.; ...

2015-06-01

In this paper, a comprehensive set of molecular-level results, primarily from classical molecular dynamics (CMD) simulations, are used to constrain CD-MUSIC surface complexation model (SCM) parameters describing rutile powder titrations conducted in RbCl, NaCl, and NaTr (Tr = triflate, CF 3SO 3 –) electrolyte media from 25 to 250 °C. Rb + primarily occupies the innermost tetradentate binding site on the rutile (110) surface at all temperatures (25, 150, 250 °C) and negative charge conditions (-0.1 and -0.2 C/m 2) probed via CMD simulations, reflecting the small hydration energy of this large, monovalent cation. Consequently, variable SCM parameters (Stern-layer capacitancemore » values and intrinsic Rb + binding constants) were adjusted relatively easily to satisfactorily match the CMD and titration data. The larger hydration energy of Na + results in a more complex inner-sphere distribution, which shifts from bidentate to tetradentate binding with increasing negative charge and temperature, and this distribution was not matched well for both negative charge conditions, which may reflect limitations in the CMD and/or SCM approaches. Finally, in particular, the CMD axial density profiles for Rb + and Na + reveal that peak binding distances shift toward the surface with increasing negative charge, suggesting that the CD-MUSIC framework may be improved by incorporating CD or Stern-layer capacitance values that vary with charge.« less

Desorption isotherms of salted minced pork using K-lactate as a substitute for NaCl.

PubMed

Muñoz, I; Arnau, J; Costa-Corredor, A; Gou, P

2009-12-01

The aim of this study was to obtain and compare water desorption isotherms of ground meat containing NaCl (0.107kg NaCl/kg raw-meat dry matter) and/or K-lactate as NaCl substitute at two different levels of molar substitution (30% and 100%). A thin layer of salted ground meat was dried and sampled at pre-determined times. The moisture content of the samples and their water activities (a(w)) were measured at 5°C and 25°C. Results showed that ground meat with NaCl and/or different K-lactate contents had a similar water desorption isotherm for a(w) ranging from 0.7 to 1.0. Below 0.7, the water equilibrium content fell with small decreases in a(w) faster for meat with NaCl than for meat with K-lactate. K-lactate could reduce the excessive hardening at the surface of salted meat products. Experimental desorption isotherms were compared to those estimated using two approaches of the Ross equation. Models provided a good fit for the experimental data.

Optimisation and performance of NaClO-assisted maintenance cleaning for fouling control in membrane bioreactors.

PubMed

Wang, Zhizhen; Meng, Fangang; He, Xiang; Zhou, Zhongbo; Huang, Li-Nan; Liang, Shuang

2014-04-15

Based on conventional chemical cleaning and physical backflush methods, a novel in situ chemical backflush method, i.e., chemically assisted maintenance cleaning with NaClO as the principal reagent, was developed for membrane fouling control in membrane bioreactors (MBRs). The results demonstrated that, compared with a control MBR with water backflush, the use of low NaClO loads had few adverse effects on nutrient removal; on the contrary, the exposure to NaClO enhanced the denitrification performance of the MBR as a result of the formation of sludge granules. Measurements of transmembrane pressure (TMP) showed that an NaClO backflush at 0.2 ppm could achieve effective membrane fouling control in MBRs. Ex situ backflush tests showed that an NaClO backflush enhanced the detachment of biopolymers from the fouled membranes compared with a water backflush. Comparative 16S rRNA sequencing showed differing bacterial community composition in the fouling layers of the two MBRs. Specifically, the NaClO backflush could suppress filament-caused membrane fouling (i.e., lowered the abundance of Thiothrix eikelboomii in the fouling layers). Both the water and NaClO backflush resulted in significant increases in the pure water permeability of the membranes as a result of the enlargement of membrane pores. The results of Fourier transform infrared spectrometry indicated that the frequent NaClO backflush did not change the functional groups of the active layer of the membranes significantly. This study could provide an alternative for the implementation of membrane cleaning in MBR plants. Copyright © 2014 Elsevier Ltd. All rights reserved.

Solubility relations in the ternary system NaCl-CsCl-H2O at 1 atm. 1. Solubilities of halite from 20 to 100 °C

USGS Publications Warehouse

Chou, I.-Ming; Lee, R.D.

1983-01-01

Solubilities of halite in the ternary system NaCl-CsCl-H2O have been determined by the visual polythermal method at 1 atm from 20 to 100??C along five constant CsCl/(CsCl + H2O) weight ratio lines. These five constant weight ratios are 0.1, 0.2, 0.3, 0.4, and 0.5. The maximum uncertainties in these measurements are ??0.02 wt % NaCl and ??0.15??C. The data along each constant CsCl/(CsCl + H2O) weight ratio line were regressed to a smooth curve. The maximum deviation of the measured solubilities from the smooth curves is 0.06 wt % NaCl. Isothermal solubilities of halite were calculated from smoothed curves at 25, 50, and 75??C.

Equilibrium, Kinetics, and Spectroscopic Studies of SF6 Hydrate in NaCl Electrolyte Solution.

PubMed

Seo, Youngrok; Moon, Donghyun; Lee, Changho; Park, Jeong-Woo; Kim, Byeong-Soo; Lee, Gang-Woo; Dotel, Pratik; Lee, Jong-Won; Cha, Minjun; Yoon, Ji-Ho

2015-05-19

Many studies have focused on desalination via hydrate formation; however, for their potential application, knowledge pertaining to thermodynamic stability, formation kinetics, and guest occupation behavior in clathrate hydrates needs to be determined. Herein, the phase equilibria of SF6 hydrates in the presence of NaCl solutions (0, 2, 4, and 10 wt %) were monitored in the temperature range of 277-286 K and under pressures of up to 1.4 MPa. The formation kinetics of SF6 hydrates in the presence of NaCl solutions (0, 2, and 4 wt %) was also investigated. Gas consumption curves of SF6 hydrates showed that a pure SF6 hydrate system allowed fast hydrate growth as well as high conversion yield, whereas SF6 hydrate in the presence of NaCl solutions showed retarded hydrate growth rate as well as low conversion yield. In addition, structural identification of SF6 hydrates with and without NaCl solutions was performed using spectroscopic tools such as Raman spectroscopy and X-ray diffraction. The Raman spectrometer was also used to evaluate the temperature-dependent release behavior of guest molecules in SF6 and SF6 + 4 wt % NaCl hydrates. The results indicate that whereas SF6 hydrate starts to decompose at around 240 K, the escape of SF6 molecules in SF6 + 4 wt % NaCl hydrate is initiated rapidly at around 205 K. The results of this study can provide a better understanding of guest-host interaction in electrolyte-containing systems.

Mechanical behavior of nanocrystalline NaCl islands on Cu(111).

PubMed

Bombis, Ch; Ample, F; Mielke, J; Mannsberger, M; Villagómez, C J; Roth, Ch; Joachim, C; Grill, L

2010-05-07

The mechanical response of ultrathin NaCl crystallites of nanometer dimensions upon manipulation with the tip of a scanning tunneling microscope (STM) is investigated, expanding STM manipulation to various nanostructuring modes of inorganic materials as cutting, moving, and cracking. In the light of theoretical calculations, our results reveal that atomic-scale NaCl islands can behave elastically and follow a classical Hooke's law. When the elastic limit of the nanocrystallites is reached, the STM tip induces atomic dislocations and consequently the regime of plastic deformation is entered. Our methodology is paving the way to understand the mechanical behavior and properties of other nanoscale materials.

Surface chemical properties of eutectic and frozen NaCl solutions probed by XPS and NEXAFS.

PubMed

Křepelová, Adéla; Huthwelker, Thomas; Bluhm, Hendrik; Ammann, Markus

2010-12-17

We study the surface of sodium chloride-water mixtures above, at, and below the eutectic temperature using X-ray photoelectron spectroscopy (XPS) and electron-yield near-edge X-ray absorption fine structure (NEXAFS) spectroscopy. The NaCl frozen solutions are mimicking sea-salt deposits in ice or snow. Sea-salt particles emitted from the oceans are a major contributor to the global aerosol burden and can act as a catalyst for heterogeneous chemistry or as cloud condensation nuclei. The nature of halogen ions at ice surfaces and their influence on surface melting of ice are of significant current interest. We found that the surface of the frozen solution, depending on the temperature, consists of ice and different NaCl phases, that is, NaCl, NaCl·2H(2)O, and surface-adsorbed water.

Control of Cl- transport in the operculum epithelium of Fundulus heteroclitus: long- and short-term salinity adaptation.

PubMed

Hoffmann, E K; Hoffmann, E; Lang, F; Zadunaisky, J A

2002-11-13

The eurohaline fish, Fundulus heteroclitus, adapts rapidly to enhanced salinity by increasing the ion secretion by gill chloride cells. An increase of approximately 70 mOsm in plasma osmolarity was previously found during the transition. To mimic this in vitro, isolated opercular epithelia of seawater-adapted Fundulus mounted in a modified Ussing chamber were exposed to an increase in NaCl and/or osmolarity on the basolateral side, which immediately increased I(SC). Various Cl(-) channel blockers as well as the K(+) channel blocker Ba(2+) added to the basolateral side all inhibited the steady-state as well as the hypertonic stimulation of I(SC). The exists -agonist isoproterenol stimulates I(SC) in standard Ringer solutions. In contrast, when cell volume was kept at the larger value by simultaneous addition of water, the stimulation with isoproterenol was abolished, suggesting that the key process for activation of the Na(+), K(+), 2Cl(-) cotransporter is cell shrinkage. The protein kinase C (PKC) inhibitor chelerythrine and the myosin light chain kinase (MLCK) inhibitor ML-7 had strong inhibitory effects on the mannitol activation of I(SC), thus both MLCK and PKC are involved. The two specific protein kinase A (PKA) inhibitors H-89 and KT 5720 had no effect after mannitol addition whereas isoproterenol stimulation was completely blocked by H-89. This indicates that PKA is involved in the activation of the apical Cl(-) channel via c-AMP whereas the shrinkage activation of the Na(+), K(+), 2Cl(-) cotransporter is independent of PKA activation. The steady-state Cl(-) secretion was stimulated by an inhibitor of serine/threonine phosphatases of the PP-1 and PP-2A type and inhibited by a PKC inhibitor but not by a PKA inhibitor. Thus, it seems to be determined by continuous phosphorylation and dephosphorylation involving PKC but not PKA. The steady-state Cl(-) secretion and the maximal obtainable Cl(-) secretion were measured in freshwater-adapted fish and in fish

High Brain Ammonia Tolerance and Down-Regulation of Na+:K+:2Cl- Cotransporter 1b mRNA and Protein Expression in the Brain of the Swamp Eel, Monopterus albus, Exposed to Environmental Ammonia or Terrestrial Conditions

PubMed Central

Ip, Yuen K.; Hou, Zhisheng; Chen, Xiu L.; Ong, Jasmine L. Y.; Chng, You R.; Ching, Biyun; Hiong, Kum C.; Chew, Shit F.

2013-01-01

Na+:K+:2Cl- cotransporter 1 (NKCC1) has been implicated in mediating ischemia-, trauma- or ammonia-induced astrocyte swelling/brain edema in mammals. This study aimed to determine the effects of ammonia or terrestrial exposure on ammonia concentrations in the plasma and brain, and the mRNA expression and protein abundance of nkcc/Nkcc in the brain, of the swamp eel Monopterus albus . Ammonia exposure led to a greater increase in the ammonia concentration in the brain of M. albus than terrestrial exposure. The brain ammonia concentration of M. albus reached 4.5 µmol g-1 and 2.7 µmol g-1 after 6 days of exposure to 50 mmol l-1 NH4Cl and terrestrial conditions, respectively. The full cDNA coding sequence of nkcc1b from M. albus brain comprised 3276 bp and coded for 1092 amino acids with an estimated molecular mass of 119.6 kDa. A molecular characterization indicated that it could be activated through phosphorylation and/or glycosylation by osmotic and/or oxidative stresses. Ammonia exposure for 1 day or 6 days led to significant decreases in the nkcc1b mRNA expression and Nkcc1b protein abundance in the brain of M. albus. In comparison, a significant decrease in nkcc1b mRNA expression was observed in the brain of M. albus only after 6 days of terrestrial exposure, but both 1 day and 6 days of terrestrial exposure resulted in significant decreases in the protein abundance of Nkcc1b. These results are novel because it has been established in mammals that ammonia up-regulates NKCC1 expression in astrocytes and NKCC1 plays an important role in ammonia-induced astrocyte swelling and brain edema. By contrast, our results indicate for the first time that M. albus is able to down-regulate the mRNA and protein expression of nkcc1b/Nkcc1b in the brain when confronted with ammonia toxicity, which could be one of the contributing factors to its extraordinarily high brain ammonia tolerance. PMID:24069137

Antenatal Bartter syndrome presenting as hyperparathyroidism with hypercalcemia and hypercalciuria: a case report and review.

PubMed

Gross, Itai; Siedner-Weintraub, Yael; Simckes, Ari; Gillis, David

2015-07-01

Antenatal type I Bartter syndrome (ABS) is usually identified by the presence of polyhydramnios, premature delivery, hypokalemia, metabolic alkalosis, hypercalciuria, and nephrocalcinosis caused by mutations in the Na-K-2Cl cotransporter (NKCC2)-encoding SLC12A1 gene. In this report, we describe a novel presentation of this syndrome with hypercalcemic hypercalciuric hyperparathyroidism, and review the literature of the variable atypical presentations of ABS.

Sodium relations in desert plants: 8. Differential effects of NaCl and Na/sub 2/SO/sub 4/ on growth and composition of Atriplex hymenelytra (desert holly)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Soufi, S.M.; Wallace, A.

1982-07-01

Maximum growth over a period of 3 months of Atriplex hymenelytra (Torr.) Wats. (desert holly) in solution culture was obtained when the nutrient solution contained 5 x 10/sup -2/ N NaCl. Sodium concentratons in leaves at maximum yield was 7.88% and that of Cl was also 7.88%. In the presence of 10/sup -2/ N Na/sub 2/SO/sub 4/, there was much less growth than with 10/sup -2/ N NaCl. The highest NaCl level depressed levels of K, Ca, and Mg in leaves, stems, and roots. The highest NaCl level also decreased levels of micronutrients in many of the plants.

Spectroelectrochemistry of EuCl 3 in Four Molten Salt Eutectics; 3 LiCl−NaCl, 3 LiCl−2 KCl, LiCl−RbCl, and 3 LiCl−2 CsCl; at 873 K

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schroll, Cynthia A.; Chatterjee, Sayandev; Levitskaia, Tatiana

Key electrochemical properties affecting pyroprocessing of nuclear fuel were examined in four eutectic melts using using Eu3+/2+ as a representative probe. We report the electrochemical and spectroelectrochemical behavior of EuCl3 in four molten salt eutectics (3 LiCl – NaCl, 3 LiCl – 2 KCl, LiCl – RbCl and 3 LiCl – 2 CsCl) at 873 K. Cyclic voltammetry was used to determine the redox potential for Eu3+/2+ and the applied potentials for spectroelectrochemistry. Single step chronoabsorptometry and thin-layer spectroelectrochemistry were used to obtain the number of electrons transferred, redox potentials and diffusion coefficients for Eu3+ in each eutectic melt. Themore » redox potentials determined by thin-layer spectroelectrochemistry were extremely close to those obtained using cyclic voltammetry. The redox potential for Eu3+/2+ was most positive in the 3 LiCl - NaCl melt, showed a negative shift in the 3 LiCl - 2 KCl melt, and was the most negative in the LiCl - RbCl and 3 LiCl - 2 CsCl eutectics. The diffusion coefficient for Eu3+ followed this same trend; it was the largest in the 3 LiCl - NaCl melt and the smallest in the LiCl - RbCl and 3 LiCl - 2 CsCl melts. The basic one-electron reversible electron transfer for Eu3+/2+ was not changed by melt composition.« less

Supercooling of aqueous NaCl and KCl solutions under acoustic levitation.

PubMed

Lü, Y J; Wei, B

2006-10-14

The supercooling capability of aqueous NaCl and KCl solutions is investigated at containerless state by using acoustic levitation method. The supercooling of water is obviously enhanced by the alkali metal ions and increases linearly with the augmentation of concentrations. Furthermore, the supercooling depends on the nature of ions and is 2-3 K larger for NaCl solution than that for KCl solution in the present concentration range: Molecular dynamics simulations are performed to reveal the intrinsic correlation between supercoolability and microstructure. The translational and orientational order parameters are applied to quantitatively demonstrate the effect of ionic concentration on the hydrogen-bond network and ice melting point. The disrupted hydrogen-bond structure determines essentially the concentration dependence of supercooling. On the other hand, the introduced acoustic pressure suppresses the increase of supercooling by promoting the growth and coalescence of microbubbles, the effective nucleation catalysts, in water. However, the dissolved ions can weaken this effect, and moreover the degree varies with the ion type. This results in the different supercoolability for NaCl and KCl solutions under the acoustic levitation conditions.

Nedd4-2 Modulates Renal Na+-Cl− Cotransporter via the Aldosterone-SGK1-Nedd4-2 Pathway

PubMed Central

Arroyo, Juan Pablo; Lagnaz, Dagmara; Ronzaud, Caroline; Vázquez, Norma; Ko, Benjamin S.; Moddes, Lauren; Ruffieux-Daidié, Dorothée; Hausel, Pierrette; Koesters, Robert; Yang, Baoli; Stokes, John B.; Hoover, Robert S.

2011-01-01

Regulation of renal Na+ transport is essential for controlling blood pressure, as well as Na+ and K+ homeostasis. Aldosterone stimulates Na+ reabsorption by the Na+-Cl− cotransporter (NCC) in the distal convoluted tubule (DCT) and by the epithelial Na+ channel (ENaC) in the late DCT, connecting tubule, and collecting duct. Aldosterone increases ENaC expression by inhibiting the channel's ubiquitylation and degradation; aldosterone promotes serum-glucocorticoid-regulated kinase SGK1-mediated phosphorylation of the ubiquitin-protein ligase Nedd4-2 on serine 328, which prevents the Nedd4-2/ENaC interaction. It is important to note that aldosterone increases NCC protein expression by an unknown post-translational mechanism. Here, we present evidence that Nedd4-2 coimmunoprecipitated with NCC and stimulated NCC ubiquitylation at the surface of transfected HEK293 cells. In Xenopus laevis oocytes, coexpression of NCC with wild-type Nedd4-2, but not its catalytically inactive mutant, strongly decreased NCC activity and surface expression. SGK1 prevented this inhibition in a kinase-dependent manner. Furthermore, deficiency of Nedd4-2 in the renal tubules of mice and in cultured mDCT15 cells upregulated NCC. In contrast to ENaC, Nedd4-2-mediated inhibition of NCC did not require the PY-like motif of NCC. Moreover, the mutation of Nedd4-2 at either serine 328 or 222 did not affect SGK1 action, and mutation at both sites enhanced Nedd4-2 activity and abolished SGK1-dependent inhibition. Taken together, these results suggest that aldosterone modulates NCC protein expression via a pathway involving SGK1 and Nedd4-2 and provides an explanation for the well-known aldosterone-induced increase in NCC protein expression. PMID:21852580

Vascular influences of calcium supplementation and vitamin D-induced hypercalcemia in NaCl-hypertensive rats.

PubMed

Kähönen, Mika; Näppi, Satu; Jolma, Pasi; Hutri-Kähönen, Nina; Tolvanen, Jari-Petteri; Saha, Heikki; Koivisto, Pasi; Krogerus, Leena; Kalliovalkama, Jarkko; Pörsti, Ilkka

2003-09-01

This 8-week study investigated the effects of increasing dietary Ca2+ content from 1.0% to 3.0% and hypercalcemia induced by oral 1alpha-OH vitamin D3 (1OH-D3, 1.2 microg/kg), on arterial tone in NaCl-hypertensive rats. The high-Ca2+ diet completely prevented the increase in blood pressure induced by the 6.0% NaCl chow, while plasma total Ca2+ and body weight were not different from controls. The 1OH-D3 treatment moderately elevated plasma total Ca2+ and attenuated the NaCl-induced rise in blood pressure, but also impaired weight gain. The tone of isolated mesenteric arterial rings was examined at the end of study. The endothelium-independent relaxations to nitroprusside, isoproterenol, and cromakalim were impaired in NaCl-hypertension. Experiments with NG-nitro-l-arginine methyl ester and tetraethylammonium in vitro suggested that both the nitric oxide- and hyperpolarization-mediated components of endothelium-dependent relaxation to acetylcholine were reduced in NaCl-hypertensive rats. All of the impaired relaxations in NaCl hypertension were normalized by concomitant Ca2+ supplementation. The 1OH-D3 treatment did not affect vascular relaxation, but it attenuated maximal contractile responses induced by norepinephrine and KCl by more than 50%. The reduced vasoconstrictor responses could not be explained by increased apoptosis in the vessel wall, but calcification may have played a role, since moderate signs of medial or adventitial calcification were observed in the aortic preparations after the 1OH-D3 treatment. In conclusion, a high-Ca2+ diet, which did not cause hypercalcemia, normalized blood pressure and endothelium-dependent and endothelium-independent vasorelaxation in NaCl-hypertensive rats. In contrast, chronic hypercalcemia induced by 1OH-D3 was associated with moderately lowered blood pressure, possibly because of reduced vasoconstrictor responses in arterial smooth muscle.

An Application of Specific Sensors For The Monitoring of NaCl in Soft Cheeses

NASA Astrophysics Data System (ADS)

Lvova, Larisa; Mielle, Patrick; Salles, Christian; Denis, Sylvain; Vergoignan, Catherine; Barra, Aurélien; Di Natale, Corrado; Paolesse, Roberto; Temple-Boyer, Pierre; Feron, Gilles

2011-09-01

The commercial sensors and prototype ISEs array (Ion Selective Electrodes array) were utilized for NaCl concentration measurements in soft cheeses, in particular in vitro gut process and in commercial Italian mozzarella cheeses. The values obtained from the sensors were compared with HPLC analysis. The results showed the feasibility of the ISE array application to monitor NaCl in soft cheese during the breakdown in the digester. The best results were obtained with the use of ISEs array combining, in particular, Cl- and Na+ detections. The salinity of commercial mozzarella cheese samples and the originally utilized milk type (cow or buffalo) were also satisfactory determined with the developed ISE array.

SLC4A11 is an EIPA-sensitive Na+ permeable pHi regulator

PubMed Central

Ogando, Diego G.; Jalimarada, Supriya S.; Zhang, Wenlin; Vithana, Eranga N.

2013-01-01

Slc4a11, a member of the solute linked cotransporter 4 family that is comprised predominantly of bicarbonate transporters, was described as an electrogenic 2Na+-B(OH)4− (borate) cotransporter and a Na+-2OH− cotransporter. The goal of the current study was to confirm and/or clarify the function of SLC4A11. In HEK293 cells transfected with SLC4A11 we tested if SLC4A11 is a: 1) Na+-HCO3− cotransporter, 2) Na+-OH−(H+) transporter, and/or 3) Na+-B(OH)4− cotransporter. CO2/HCO3− perfusion yielded no significant differences in rate or extent of pHi changes or Na+ flux in SLC4A11-transfected compared with control cells. Similarly, in CO2/HCO3−, acidification on removal of Na+ and alkalinization on Na+ add back were not significantly different between control and transfected indicating that SLC4A11 does not have Na+-HCO3− cotransport activity. In the absence of CO2/HCO3−, SLC4A11-transfected cells showed higher resting intracelllular Na+ concentration ([Na+]i; 25 vs. 17 mM), increased NH4+-induced acidification and increased acid recovery rate (160%) after an NH4 pulse. Na+ efflux and influx were faster (80%) following Na+ removal and add back, respectively, indicative of Na+-OH−(H+) transport by SLC4A11. The increased alkalinization recovery was confirmed in NHE-deficient PS120 cells demonstrating that SLC4A11 is a bonafide Na+-OH−(H+) transporter and not an activator of NHEs. SLC4A11-mediated H+ efflux is inhibited by 5-(N-ethyl-N-isopropyl) amiloride (EIPA; EC50: 0.1 μM). The presence of 10 mM borate did not alter dpHi/dt or ΔpH during a Na+-free pulse in SLC4A11-transfected cells. In summary our results show that SLC4A11 is not a bicarbonate or borate-linked transporter but has significant EIPA-sensitive Na+-OH−(H+) and NH4+ permeability. PMID:23864606

Water activities of NaClO4, Ca(ClO4)2, and Mg(ClO4)2 brines from experimental heat capacities: Water activity >0.6 below 200 K

NASA Astrophysics Data System (ADS)

Toner, J. D.; Catling, D. C.

2016-05-01

Perchlorate salts found on Mars are extremely hygroscopic and form low eutectic temperature aqueous solutions, which could allow liquid water to exist on Mars despite cold and dry conditions. The formation, dynamics, and potential habitability of perchlorate salt solutions can be broadly understood in terms of water activity. Water activity controls condensation and evaporation of water vapor in brines, deliquescence and efflorescence of crystalline salts, and ice formation during freezing. Furthermore, water activity is a basic parameter defining the habitability of aqueous solutions. Despite the importance of water activity, its value in perchlorate solutions has only been measured at 298.15 K and at the freezing point of water. To address this lack of data, we have determined water activities in NaClO4, Ca(ClO4)2, and Mg(ClO4)2 solutions using experimental heat capacities measured by Differential Scanning Calorimetry. Our results include concentrations up to near-saturation and temperatures ranging from 298.15 to 178 K. We find that water activities in NaClO4 solutions increase with decreasing temperature, by as much as 0.25 aw from 298.15 to 178 K. Consequently, aw reaches ∼0.6-0.7 even for concentrations up to 15 molal NaClO4 below 200 K. In contrast, water activities in Ca(ClO4)2 and Mg(ClO4)2 solutions generally decrease with decreasing temperature. The temperature dependence of water activity indicates that low-temperature NaClO4 solutions will evaporate and deliquesce at higher relative humidity, crystallize ice at higher temperature, and potentially be more habitable for life (at least in terms of water activity) compared to solutions at 298.15 K. The opposite effects occur in Ca(ClO4)2 and Mg(ClO4)2 solutions.

Interaction of stress and dietary NaCl intake in hypertension: renal neural mechanisms.

PubMed

DiBona, Gerald F

2013-10-01

A synthesizing concept of the development of primary hypertension is that it arises from an interaction of genetic and environmental factors. Of the environmental factors, dietary NaCl intake and mental stress are among the most thoroughly investigated. This review will focus on the interaction between genetic predisposition and the environmental influences of dietary NaCl intake and mental stress in the development of primary hypertension.

Synthesis, structure and optical properties of two isotypic crystals, Na{sub 3}MO{sub 4}Cl (M=W, Mo)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Han, Shujuan; Bai, Chunyan; Zhang, Bingbing

Two isotypic compounds, Na{sub 3}MO{sub 4}Cl (M = W, Mo) have been obtained from the high temperature solution, and their structures were determined by single-crystal X-ray diffraction. Both of them crystallize in the space group P4/nmm of tetragonal system with the unit cells: a=7.5181(15), c=5.360(2) for Na{sub 3}WO{sub 4}Cl and a=7.4942(12), c=5.3409(18) for Na{sub 3}MoO{sub 4}Cl. The structure exhibits a 3D network built up by the ClNa{sub 6} groups, and the MO{sub 4} groups reside in the tunnels of the 3D network. The structural similarities and differences between Na{sub 3}MO{sub 4}Cl (M=W, Mo) and Sr{sub 3}MO{sub 4}F (M=Al, Ga) havemore » been discussed. Meanwhile, detailed structure comparison analyses between Na{sub 3}MO{sub 4}Cl (M=W, Mo) and Na{sub 3}MO{sub 4}F (M=W, Mo) indicate that the different connection modes of ClNa{sub 6} and FNa{sub 6} make Na{sub 3}MO{sub 4}Cl and Na{sub 3}MO{sub 4}F crystallize in different structures. The IR spectra were used to verify the validity of the structure. The diffuse reflectance spectra show that the UV absorption edges are about 249 nm (4.99 eV) and 265 nm (4.69 eV) for Na{sub 3}WO{sub 4}Cl and Na{sub 3}MoO{sub 4}Cl, respectively. In addition, the first-principles theoretical studies are also carried out to aid the understanding of electronic structures and linear optical properties. - Graphical abstract: Two isotypic compounds, Na{sub 3}MO{sub 4}Cl (M=W, Mo) have been obtained from the high temperature solution. Both of them crystallize in the space group P4/nmm of tetragonal system. The structure exhibits a 3D network built up by the ClNa{sub 6} groups, and the MO{sub 4} groups reside in the tunnels of the 3D network. - Highlights: • Structure and properties of Na{sub 3}MO{sub 4}Cl (M=W, Mo) are reported for the first time. • They show a 3D network built by ClNa{sub 6}, and WO{sub 4} lies in the tunnels of the network. • IR spectra were used to verify the validity of the structure. • Band structures

Long Life Na/NiCl2 Cells

NASA Technical Reports Server (NTRS)

Bugga, Ratnakumar V. (Inventor); Surampudi, Subbarao (Inventor); Halpert, Gerald (Inventor)

1996-01-01

The premature capacity failure of Na/NiCl2 secondary cells due to agglomeration of nickel particles on the surface of the NiCl2 cathode is prevented by addition of a minor amount such as 10 percent by weight of a transition metal such as Co, Fe or Mn to the cathode. The chlorides of the transition metals have lower potentials than nickel chloride and chlorinate during charge. A uniform dispersion of the transition metals in the cathodes prevents agglomeration of nickel, maintains morphology of the electrode, maintains the electrochemical area of the electrode and thus maintains capacity of the electrode. The additives do not effect sintering. The addition of sulfur to the liquid catholyte is expected to further reduce agglomeration of nickel in the cathode.

Hypokalemia and Pendrin Induction by Aldosterone.

PubMed

Xu, Ning; Hirohama, Daigoro; Ishizawa, Kenichi; Chang, Wen Xiu; Shimosawa, Tatsuo; Fujita, Toshiro; Uchida, Shunya; Shibata, Shigeru

2017-05-01

Aldosterone plays an important role in regulating Na-Cl reabsorption and blood pressure. Epithelial Na + channel, Na + -Cl - cotransporter, and Cl - /HCO 3 - exchanger pendrin are the major mediators of Na-Cl transport in the aldosterone-sensitive distal nephron. Existing evidence also suggests that plasma K + concentration affects renal Na-Cl handling. In this study, we posited that hypokalemia modulates the effects of aldosterone on pendrin in hyperaldosteronism. Chronic aldosterone infusion in mice increased pendrin levels at the plasma membrane, and correcting hypokalemia in this model almost completely blocked pendrin upregulation. However, hypokalemia induced by a low-K + diet resulted in pendrin downregulation along with reduced plasma aldosterone levels, indicating that both hypokalemia and aldosterone excess are necessary for pendrin induction. In contrast, decreased plasma K + levels were sufficient to increase Na + -Cl - cotransporter levels. We found that phosphorylation of mineralocorticoid receptor that prevents aldosterone binding in intercalated cells was suppressed by hypokalemia, which resulted in enhanced pendrin response to aldosterone, explaining the coordinated action of aldosterone and hypokalemia in pendrin regulation. Finally, to address the physiological significance of our observations, we administered aldosterone to mice lacking pendrin. Notably, plasma K + levels were significantly lower in pendrin knockout mice (2.7±0.1 mmol/L) than in wild-type mice (3.0±0.1 mmol/L) after aldosterone infusion, demonstrating that pendrin alleviates hypokalemia in a state of aldosterone excess. These data indicate that the decreased plasma K + levels promote pendrin induction by aldosterone, which, in concert with Na + -Cl - cotransporter, counteracts the progression of hypokalemia but promotes hypertension in primary aldosterone excess. © 2017 American Heart Association, Inc.

Interaction of chromatin with NaCl and MgCl2. Solubility and binding studies, transition to and characterization of the higher-order structure.

PubMed

Ausio, J; Borochov, N; Seger, D; Eisenberg, H

1984-08-15

Chicken erythrocyte chromatin containing histones H1 and H5 was carefully separated into a number of well-characterized fractions. A distinction could be made between chromatin insoluble in NaCl above about 80 mM, and chromatin soluble at all NaCl concentrations. Both chromatin forms were indistinguishable electrophoretically and both underwent the transition from the low salt "10 nm" coil to the "30 nm" higher-order structure solenoid by either raising the MgCl2 concentration to about 0.3 mM or the NaCl concentration to about 75 mM. The transitions were examined in detail by elastic light-scattering procedures. It could be shown that the 10 nm form is a flexible coil. For the 30 nm solenoid, the assumption of a rigid cylindrical structure was in good agreement with 5.7 nucleosomes per helical turn. However, disagreement of calculated frictional parameters with values derived from quasielastic light-scattering and sedimentation introduced the possibility that the higher-order structure, under these conditions, is more extended, flexible, or perhaps a mixture of structures. Values for density and refractive index increments of chromatin are also given. To understand the interaction of chromatin with NaCl and with MgCl2, a number of experiments were undertaken to study solubility, precipitation, conformational transitions and binding of ions over a wide range of experimental conditions, including chromatin concentration.

N-ethylmaleimide activates a Cl(-)-independent component of K(+) flux in mouse erythrocytes.

PubMed

Shmukler, Boris E; Hsu, Ann; Alves, Jessica; Trudel, Marie; Rust, Marco B; Hubner, Christian A; Rivera, Alicia; Alper, Seth L

2013-06-01

The K-Cl cotransporters (KCCs) of mouse erythrocytes exhibit higher basal activity than those of human erythrocytes, but are similarly activated by cell swelling, by hypertonic urea, and by staurosporine. However, the dramatic stimulation of human erythroid KCCs by N-ethylmaleimide (NEM) is obscured in mouse erythrocytes by a prominent NEM-stimulated K(+) efflux that lacks Cl(-)-dependence. The NEM-sensitivity of Cl(-)-independent K(+) efflux of mouse erythrocytes is lower than that of KCC. The genetically engineered absence of the K-Cl cotransporters KCC3 and KCC1 from mouse erythrocytes does not modify Cl(-)-independent K(+) efflux. Mouse erythrocytes genetically devoid of the Gardos channel KCNN4 show increased NEM-sensitivity of both Cl(-)-independent K(+) efflux and K-Cl cotransport. The increased NEM-sensitivity and stimulation magnitude of Cl(-)-independent K(+) efflux in mouse erythrocytes expressing transgenic hypersickling human hemoglobin SAD (HbSAD) are independent of the presence of KCC3 and KCC1, but absence of KCNN4 reduces the stimulatory effect of HbSAD. NEM-stimulated Cl(-)-independent K(+) efflux of mouse red cells is insensitive to ouabain and bumetanide, but partially inhibited by chloroquine, barium, and amiloride. The NEM-stimulated activity is modestly reduced at pH6.0 but not significantly altered at pH8.0, and is abolished at 0°C. Although the molecular identity of this little-studied K(+) efflux pathway of mouse erythrocytes remains unknown, its potential role in the pathophysiology of sickle red cell dehydration will be important for the extrapolation of studies in mouse models of sickle cell disease to our understanding of humans with sickle cell anemia. Copyright © 2013 Elsevier Inc. All rights reserved.

Corrosion Properties of SAC305 Solder in Different Solution of HCl and NaCl

NASA Astrophysics Data System (ADS)

Nurwahida, M. Z.; Mukridz, M. M.; Ahmad, A. M.; Muhammad, F. M. N.

2018-03-01

Potentiodynamic polarization was used to studied the corrosion properties of SAC305 solder in different solution of 1.0 M HCl and 3.5 wt.% NaCl using the same scanning rate of 1.0 mV/s. The polarization curves indicated that corrosion in NaCl was less severe than in HCl solution based on corrosion current and passivation behavior obtained. Morphology and phases obtained after corrosion using SEM and XRD were analyzed. Microstructure analysis shows the present of compact corrosion product with presence of larger flake for polarization in NaCl compared to HCl. Phases present in XRD analysis confirmed the present of SnO and SnO2 corrosion product for sample from both solutions.

Heterogeneous Ice Nucleation Ability of NaCl and Sea Salt Aerosol Particles at Cirrus Temperatures

NASA Astrophysics Data System (ADS)

Wagner, Robert; Kaufmann, Julia; Möhler, Ottmar; Saathoff, Harald; Schnaiter, Martin; Ullrich, Romy; Leisner, Thomas

2018-03-01

In situ measurements of the composition of heterogeneous cirrus ice cloud residuals have indicated a substantial contribution of sea salt in sampling regions above the ocean. We have investigated the heterogeneous ice nucleation ability of sodium chloride (NaCl) and sea salt aerosol (SSA) particles at cirrus cloud temperatures between 235 and 200 K in the Aerosol Interaction and Dynamics in the Atmosphere aerosol and cloud chamber. Effloresced NaCl particles were found to act as ice nucleating particles in the deposition nucleation mode at temperatures below about 225 K, with freezing onsets in terms of the ice saturation ratio, Sice, between 1.28 and 1.40. Above 225 K, the crystalline NaCl particles deliquesced and nucleated ice homogeneously. The heterogeneous ice nucleation efficiency was rather similar for the two crystalline forms of NaCl (anhydrous NaCl and NaCl dihydrate). Mixed-phase (solid/liquid) SSA particles were found to act as ice nucleating particles in the immersion freezing mode at temperatures below about 220 K, with freezing onsets in terms of Sice between 1.24 and 1.42. Above 220 K, the SSA particles fully deliquesced and nucleated ice homogeneously. Ice nucleation active surface site densities of the SSA particles were found to be in the range between 1.0 · 1010 and 1.0 · 1011 m-2 at T < 220 K. These values are of the same order of magnitude as ice nucleation active surface site densities recently determined for desert dust, suggesting a potential contribution of SSA particles to low-temperature heterogeneous ice nucleation in the atmosphere.

Molecular Dynamics Simulation of Surface Tension of NaCl Aqueous Solution at 298.15K: from Diluted to Highly Supersaturated Concentrations

NASA Astrophysics Data System (ADS)

Wang, Xiaoxiang; Chen, Chuchu; Poeschl, Ulirch; Su, Hang; Cheng, Yafang

2017-04-01

Sodium chloride (NaCl) is one of the key components of atmospheric aerosol particles. Concentration-depend surface tension of aqueous NaCl solution is essential to determine the equilibrium between droplet NaCl solution and water vapor, which is important in regards to aerosol-cloud interaction and aerosol climate effects. Although supersaturated NaCl droplets can be widely found under atmospheric conditions, the experimental determined concentration dependency of surface tension is limited up to the saturated concentration range due to technical difficulties, i.e., heterogeneous nucleation since nearly all surface tension measurement techniques requires contact of the sensor and solution surface. In this study, the surface tension of NaCl aqueous solution with solute mass fraction from 0 to 1 was calculated using molecular dynamics (MD) simulation. The surface tension increases monotonically and near linearly when mass fraction of NaCl (xNaCl) is lower than 0.265 (saturation point), which follows theoretical predictions (e.g., E-AIM, SP parameterization, and PK parameterization). Once entering into the supersaturated concentration range, the calculated surface tension starts to deviate from the near-linear extrapolation and adopts a slightly higher increasing rate until xNaCl of 0.35. We found that these two increasing phases (xNaCl 0.35) is mainly driven by the increase of excessive surface enthalpy when the solution becomes concentrated. After that, the surface tension remains almost unchanged until xNaCl of 0.52. This phenomenon is supported by the results from experiment based Differential Koehler Analyses. The stable surface tension in this concentration range is attributed to a simultaneous change of surface excess enthalpy and entropy at similar degree. When the NaCl solution is getting more concentrated than xNaCl of 0.52, the simulated surface tension regains an even faster growing momentum and shows the tendency of ultimately approaching the surface

Excretion of NaCl and KCl loads in mosquitoes. 2. Effects of the small molecule Kir channel modulator VU573 and its inactive analog VU342

PubMed Central

Rouhier, Matthew F.; Hine, Rebecca M.; Park, Seokhwan Terry; Raphemot, Rene; Denton, Jerod; Piermarini, Peter M.

2014-01-01

The effect of two small molecules VU342 and VU573 on renal functions in the yellow fever mosquito Aedes aegypti was investigated in vitro and in vivo. In isolated Malpighian tubules, VU342 (10 μM) had no effect on the transepithelial secretion of Na+, K+, Cl−, and water. In contrast, 10 μM VU573 first stimulated and then inhibited the transepithelial secretion of fluid when the tubules were bathed in Na+-rich or K+-rich Ringer solution. The early stimulation was blocked by bumetanide, suggesting the transient stimulation of Na-K-2Cl cotransport, and the late inhibition of fluid secretion was consistent with the known block of AeKir1, an Aedes inward rectifier K+ channel, by VU573. VU342 and VU573 at a hemolymph concentration of about 11 μM had no effect on the diuresis triggered by hemolymph Na+ or K+ loads. VU342 at a hemolymph concentration of 420 μM had no effect on the diuresis elicited by hemolymph Na+ or K+ loads. In contrast, the same concentration of VU573 significantly diminished the Na+ diuresis by inhibiting the urinary excretion of Na+, Cl−, and water. In K+-loaded mosquitoes, 420 μM VU573 significantly diminished the K+ diuresis by inhibiting the urinary excretion of K+, Na+, Cl−, and water. We conclude that 1) the effects of VU573 observed in isolated Malpighian tubules are overwhelmed in vivo by the diuresis triggered with the coinjection of Na+ and K+ loads, and 2) at a hemolymph concentration of 420 μM VU573 affects Kir channels systemically, including those that might be involved in the release of diuretic hormones. PMID:25056106

Norepinephrine-evoked salt-sensitive hypertension requires impaired renal sodium chloride cotransporter activity in Sprague-Dawley rats.

PubMed

Walsh, Kathryn R; Kuwabara, Jill T; Shim, Joon W; Wainford, Richard D

2016-01-15

Recent studies have implicated a role of norepinephrine (NE) in the activation of the sodium chloride cotransporter (NCC) to drive the development of salt-sensitive hypertension. However, the interaction between NE and increased salt intake on blood pressure remains to be fully elucidated. This study examined the impact of a continuous NE infusion on sodium homeostasis and blood pressure in conscious Sprague-Dawley rats challenged with a normal (NS; 0.6% NaCl) or high-salt (HS; 8% NaCl) diet for 14 days. Naïve and saline-infused Sprague-Dawley rats remained normotensive when placed on HS and exhibited dietary sodium-evoked suppression of peak natriuresis to hydrochlorothiazide. NE infusion resulted in the development of hypertension, which was exacerbated by HS, demonstrating the development of the salt sensitivity of blood pressure [MAP (mmHg) NE+NS: 151 ± 3 vs. NE+HS: 172 ± 4; P < 0.05]. In these salt-sensitive animals, increased NE prevented dietary sodium-evoked suppression of peak natriuresis to hydrochlorothiazide, suggesting impaired NCC activity contributes to the development of salt sensitivity [peak natriuresis to hydrochlorothiazide (μeq/min) Naïve+NS: 9.4 ± 0.2 vs. Naïve+HS: 7 ± 0.1; P < 0.05; NE+NS: 11.1 ± 1.1; NE+HS: 10.8 ± 0.4). NE infusion did not alter NCC expression in animals maintained on NS; however, dietary sodium-evoked suppression of NCC expression was prevented in animals challenged with NE. Chronic NCC antagonism abolished the salt-sensitive component of NE-mediated hypertension, while chronic ANG II type 1 receptor antagonism significantly attenuated NE-evoked hypertension without restoring NCC function. These data demonstrate that increased levels of NE prevent dietary sodium-evoked suppression of the NCC, via an ANG II-independent mechanism, to stimulate the development of salt-sensitive hypertension. Copyright © 2016 the American Physiological Society.

High concentrations of Na+ and Cl- ions in soil solution have simultaneous detrimental effects on growth of faba bean under salinity stress.

PubMed

Tavakkoli, Ehsan; Rengasamy, Pichu; McDonald, Glenn K

2010-10-01

Despite the fact that most plants accumulate both sodium (Na(+)) and chloride (Cl(-)) ions to high concentration in their shoot tissues when grown in saline soils, most research on salt tolerance in annual plants has focused on the toxic effects of Na(+) accumulation. There have also been some recent concerns about the ability of hydroponic systems to predict the responses of plants to salinity in soil. To address these two issues, an experiment was conducted to compare the responses to Na(+) and to Cl(-) separately in comparison with the response to NaCl in a soil-based system using two varieties of faba bean (Vicia faba), that differed in salinity tolerance. The variety Nura is a salt-sensitive variety that accumulates Na(+) and Cl(-) to high concentrations while the line 1487/7 is salt tolerant which accumulates lower concentrations of Na(+) and Cl(-). Soils were prepared which were treated with Na(+) or Cl(-) by using a combination of different Na(+) salts and Cl(-) salts, respectively, or with NaCl. While this method produced Na(+)-dominant and Cl(-)-dominant soils, it unavoidably led to changes in the availability of other anions and cations, but tissue analysis of the plants did not indicate any nutritional deficiencies or toxicities other than those targeted by the salt treatments. The growth, water use, ionic composition, photosynthesis, and chlorophyll fluorescence were measured. Both high Na(+) and high Cl(-) reduced growth of faba bean but plants were more sensitive to Cl(-) than to Na(+). The reductions in growth and photosynthesis were greater under NaCl stress and the effect was mainly additive. An important difference to previous hydroponic studies was that increasing the concentrations of NaCl in the soil increased the concentration of Cl(-) more than the concentration of Na(+). The data showed that salinity caused by high concentrations of NaCl can reduce growth by the accumulation of high concentrations of both Na(+) and Cl(-) simultaneously, but

Neonatal allopregnanolone or finasteride administration modifies hippocampal K(+) Cl(-) co-transporter expression during early development in male rats.

PubMed

Mòdol, Laura; Casas, Caty; Llidó, Anna; Navarro, Xavier; Pallarès, Marc; Darbra, Sònia

2014-09-01

The maintenance of levels of endogenous neurosteroids (NS) across early postnatal development of the brain, particularly to the hippocampus, is crucial for their maturation. Allopregnanolone (Allop) is a NS that exerts its effect mainly through the modulation of the GABAA receptor (GABAAR). During early development, GABA, acting through GABAAR, that predominantly produces depolarization shifts to hyperpolarization in mature neurons, around the second postnatal week in rats. Several factors contribute to this change including the progressive increase of the neuron-specific K(+)/Cl(-) co-transporter 2 (KCC2) (a chloride exporter) levels. Thus, we aimed to analyze whether a different profile of NS levels during development is critical and can alter this natural progression of KCC2 stages. We administrated sustained Allop (20mg/kg) or Finasteride (5α-reductase inhibitor, 50mg/kg) from the 5th postnatal day (PD5) to PD9 and assessed changes in the hippocampal expression of KCC2 at transcript and protein levels as well as its active phosphorylated state in male rats. Taken together data indicated that manipulation of NS levels during early development influence KCC2 levels and point out the importance of neonatal NS levels for the hippocampal development. Copyright © 2014 Elsevier Ltd. All rights reserved.

Synthesis of graphene nanoflakes by grinding natural graphite together with NaCl in a planetary ball mill

NASA Astrophysics Data System (ADS)

Alinejad, Babak; Mahmoodi, Korosh

Natural graphite is a soft material that conventional milling methods fail to grind into nanoparticles. We found that adding NaCl into graphite during milling allows obtaining graphene nanoflakes of about 50×200nm2 as evidenced by Transmission Electron Microscope (TEM). NaCl particles are substantially brittle and harder than graphite, serving as milling agents by both helping to chop graphite into smaller pieces and preventing graphite particles from agglomeration. After milling, NaCl can be easily washed away by water. Probable mechanism for exfoliation of graphene during the modified ball milling may be explained by NaCl and graphene slipping or sliding against and over each other, exfoliating the graphene particles into thin layers.

Functional identification and characterization of sodium binding sites in Na symporters

PubMed Central

Loo, Donald D. F.; Jiang, Xuan; Gorraitz, Edurne; Hirayama, Bruce A.; Wright, Ernest M.

2013-01-01

Sodium cotransporters from several different gene families belong to the leucine transporter (LeuT) structural family. Although the identification of Na+ in binding sites is beyond the resolution of the structures, two Na+ binding sites (Na1 and Na2) have been proposed in LeuT. Na2 is conserved in the LeuT family but Na1 is not. A biophysical method has been used to measure sodium dissociation constants (Kd) of wild-type and mutant human sodium glucose cotransport (hSGLT1) proteins to identify the Na+ binding sites in hSGLT1. The Na1 site is formed by residues in the sugar binding pocket, and their mutation influences sodium binding to Na1 but not to Na2. For the canonical Na2 site formed by two –OH side chains, S392 and S393, and three backbone carbonyls, mutation of S392 to cysteine increased the sodium Kd by sixfold. This was accompanied by a dramatic reduction in the apparent sugar and phlorizin affinities. We suggest that mutation of S392 in the Na2 site produces a structural rearrangement of the sugar binding pocket to disrupt both the binding of the second Na+ and the binding of sugar. In contrast, the S393 mutations produce no significant changes in sodium, sugar, and phlorizin affinities. We conclude that the Na2 site is conserved in hSGLT1, the side chain of S392 and the backbone carbonyl of S393 are important in the first Na+ binding, and that Na+ binding to Na2 promotes binding to Na1 and also sugar binding. PMID:24191006

Interplay between structure and transport properties of molten salt mixtures of ZnCl2-NaCl-KCl: A molecular dynamics study.

PubMed

Manga, Venkateswara Rao; Swinteck, Nichlas; Bringuier, Stefan; Lucas, Pierre; Deymier, Pierre; Muralidharan, Krishna

2016-03-07

Molten mixtures of network-forming covalently bonded ZnCl2 and network-modifying ionically bonded NaCl and KCl salts are investigated as high-temperature heat transfer fluids for concentrating solar power plants. Specifically, using molecular dynamics simulations, the interplay between the extent of the network structure, composition, and the transport properties (viscosity, thermal conductivity, and diffusion) of ZnCl2-NaCl-KCl molten salts is characterized. The Stokes-Einstein/Eyring relationship is found to break down in these network-forming liquids at high concentrations of ZnCl2 (>63 mol. %), while the Eyring relationship is seen with increasing KCl concentration. Further, the network modification due to the addition of K ions leads to formation of non-bridging terminal Cl ions, which in turn lead to a positive temperature dependence of thermal conductivity in these melts. This new understanding of transport in these ternary liquids enables the identification of appropriate concentrations of the network formers and network modifiers to design heat transfer fluids with desired transport properties for concentrating solar power plants.

Phosphorylation decreases ubiquitylation of the thiazide-sensitive cotransporter NCC and subsequent clathrin-mediated endocytosis.

PubMed

Rosenbaek, Lena L; Kortenoeven, Marleen L A; Aroankins, Takwa S; Fenton, Robert A

2014-05-09

The thiazide-sensitive sodium chloride cotransporter, NCC, is the major NaCl transport protein in the distal convoluted tubule (DCT). The transport activity of NCC can be regulated by phosphorylation, but knowledge of modulation of NCC trafficking by phosphorylation is limited. In this study, we generated novel tetracycline-inducible Madin-Darby canine kidney type I (MDCKI) cell lines expressing NCC to examine the role of NCC phosphorylation and ubiquitylation on NCC endocytosis. In MDCKI-NCC cells, NCC was highly glycosylated at molecular weights consistent with NCC monomers and dimers. NCC constitutively cycles to the apical plasma membrane of MDCKI-NCC cells, with 20-30% of the membrane pool of NCC internalized within 30 min. The use of dynasore, PitStop2, methyl-β-cyclodextrin, nystatin, and filipin (specific inhibitors of either clathrin-dependent or -independent endocytosis) demonstrated that NCC is internalized via a clathrin-mediated pathway. Reduction of endocytosis resulted in greater levels of NCC in the plasma membrane. Immunogold electron microscopy confirmed the association of NCC with the clathrin-mediated internalization pathway in rat DCT cells. Compared with controls, inducing phosphorylation of NCC via low chloride treatment or mimicking phosphorylation by replacing Thr-53, Thr-58, and Ser-71 residues with Asp resulted in increased membrane abundance and reduced rates of NCC internalization. NCC ubiquitylation was lowest in the conditions with greatest NCC phosphorylation, thus providing a mechanism for the reduced endocytosis. In conclusion, our data support a model where NCC is constitutively cycled to the plasma membrane, and upon stimulation, it can be phosphorylated to both increase NCC activity and decrease NCC endocytosis, together increasing NaCl transport in the DCT.

Phosphorylation Decreases Ubiquitylation of the Thiazide-sensitive Cotransporter NCC and Subsequent Clathrin-mediated Endocytosis*

PubMed Central

Rosenbaek, Lena L.; Kortenoeven, Marleen L. A.; Aroankins, Takwa S.; Fenton, Robert A.

2014-01-01

The thiazide-sensitive sodium chloride cotransporter, NCC, is the major NaCl transport protein in the distal convoluted tubule (DCT). The transport activity of NCC can be regulated by phosphorylation, but knowledge of modulation of NCC trafficking by phosphorylation is limited. In this study, we generated novel tetracycline-inducible Madin-Darby canine kidney type I (MDCKI) cell lines expressing NCC to examine the role of NCC phosphorylation and ubiquitylation on NCC endocytosis. In MDCKI-NCC cells, NCC was highly glycosylated at molecular weights consistent with NCC monomers and dimers. NCC constitutively cycles to the apical plasma membrane of MDCKI-NCC cells, with 20–30% of the membrane pool of NCC internalized within 30 min. The use of dynasore, PitStop2, methyl-β-cyclodextrin, nystatin, and filipin (specific inhibitors of either clathrin-dependent or -independent endocytosis) demonstrated that NCC is internalized via a clathrin-mediated pathway. Reduction of endocytosis resulted in greater levels of NCC in the plasma membrane. Immunogold electron microscopy confirmed the association of NCC with the clathrin-mediated internalization pathway in rat DCT cells. Compared with controls, inducing phosphorylation of NCC via low chloride treatment or mimicking phosphorylation by replacing Thr-53, Thr-58, and Ser-71 residues with Asp resulted in increased membrane abundance and reduced rates of NCC internalization. NCC ubiquitylation was lowest in the conditions with greatest NCC phosphorylation, thus providing a mechanism for the reduced endocytosis. In conclusion, our data support a model where NCC is constitutively cycled to the plasma membrane, and upon stimulation, it can be phosphorylated to both increase NCC activity and decrease NCC endocytosis, together increasing NaCl transport in the DCT. PMID:24668812

Interaction of Corundum, Wollastonite and Quartz With H2O-NaCl Solutions at 800 C and 10 Kbar

NASA Astrophysics Data System (ADS)

Newton, R. C.; Manning, C. E.

2005-12-01

Aqueous fluids are potentially important transport agents in subduction zones and other high-P metamorphic environments. Recent studies indicate that at high P and T, the solubilities of major rock-forming elements are strongly enhanced by the formation of metal-chloride complexes, metal-hydroxide complexes and polynuclear metal-hydroxide clusters. However, the relative abundances of these species and the energetics of their interactions in high-pressure environments remains largely unknown. We measured the solubilities of corundum (Al2O3) and wollastonite (CaSiO3) at 800 °C and 10 kbar in H2O-NaCl solutions to halite saturation (XNaCl = 0.6) . Both minerals show marked enhancement of solubility with increasing salinity. Al2O3 mol fraction rises rapidly to XNaCl = 0.1, and then declines slowly towards halite saturation. Quenched experimental fluids have neutral pH. Modeling based on ideal solution of ions and molecules leads to a simple dissolution reaction and corresponding molality (m=mol/kg H2O) expression: Al2O3(cor) + Na+ + 3H2O = NaAl(OH)4 + Al(OH)2+ and mAl2O3 = [0.0232(aNaCl)1/4(aH2O)3/2+0.00123][1+2XNaCl/(1-XNaCl)] where H2O and NaCl activities are given by aH2O = (2-XNaCl)/(2+XNaCl) and aNaCl = 4(XNaCl)2/(1 + XNaCl)2. Wollastonite solubility in NaCl solutions is accurately described by: mCaSiO3 = 0.6734XNaCl + 0.1183(XNaCl)1/2 + 0.0204. There is a roughly 50-fold enhancement of dissolved wollastonite at halite saturation. Quenched experimental fluids are strongly basic (pH=11). A consistent dissolution reaction must therefore be similar to: CaSiO3(wo) + Na+ + Cl- = CaCl+ + OH- + HNaSiO3 Quartz solubility declines monotonically from mSiO2 = 1.248 in pure H2O to 0.20 at halite saturation. Quenched fluids are neutral, indicating that quartz does not react with solvent NaCl. The only salinity control on solubility is decrease of H2O activity. The simple dissolution behaviors to be deduced from measurements on these minerals suggest that fluid

Charging Properties of Cassiterite (alpha-SnO2) Surfaces in NaCl and RbCl Ionic Media.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rosenqvist, Jorgen K; Machesky, Michael L.; Vlcek, Lukas

2009-01-01

The acid-base properties of cassiterite ({alpha}-SnO{sub 2}) surfaces at 10-50 C were studied using potentiometric titrations of powder suspensions in aqueous NaCl and RbCl media. The proton sorption isotherms exhibited common intersection points in the pH range of 4.0-4.5 under all conditions, and the magnitude of charging was similar but not identical in NaCl and RbCl. The hydrogen bonding configuration at the oxide-water interface, obtained from classical molecular dynamics (MD) simulations, was analyzed in detail, and the results were explicitly incorporated in calculations of protonation constants for the reactive surface sites using the revised MUSIC model. The calculations indicated thatmore » the terminal SnOH{sub 2} group is more acidic than the bridging Sn{sub 2}OH group, with protonation constants (log K{sub H}) of 3.60 and 5.13 at 25 C, respectively. This is contrary to the situation on the isostructural {alpha}-TiO{sub 2} (rutile), apparently because of the difference in electronegativity between Ti and Sn. MD simulations and speciation calculations indicated considerable differences in the speciation of Na{sup +} and Rb{sup +}, despite the similarities in overall charging. Adsorbed sodium ions are almost exclusively found in bidentate surface complexes, whereas adsorbed rubidium ions form comparable numbers of bidentate and tetradentate complexes. Also, the distribution of adsorbed Na{sup +} between the different complexes shows a considerable dependence on the surface charge density (pH), whereas the distribution of adsorbed Rb{sup +} is almost independent of pH. A surface complexation model (SCM) capable of accurately describing both the measured surface charge and the MD-predicted speciation of adsorbed Na{sup +}/Rb{sup +} was formulated. According to the SCM, the deprotonated terminal group (SnOH{sup -0.40}) and the protonated bridging group (Sn{sub 2}OH{sup +0.36}) dominate the surface speciation over the entire pH range of this study (2

Charging Properties of Cassiterite (alpha-SnO2) surfaces in NaCl and RbCl Ionic Media.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rosenqvist, Jorgen K; Machesky, Michael L.; Vlcek, Lukas

2009-01-01

The acid-base properties of cassiterite (alpha-SnO2) surfaces at 10-50 degrees C were studied using potentiometric titrations of powder suspensions in aqueous NaCl and RbCl media. The proton sorption isotherms exhibited common intersection points in the pH range of 4.0-4.5 under all conditions, and the magnitude of charging was similar but not identical in NaCl and RbCl. The hydrogen bonding configuration at the oxide-water interface, obtained from classical molecular dynamics (MD) simulations, was analyzed in detail, and the results were explicitly incorporated in calculations of protonation constants for the reactive surface sites using the revised MUSIC model. The calculations indicated thatmore » the terminal SnOH2 group is more acidic than the bridging Sn2OH group, with protonation constants (log KH) of 3.60 and 5.13 at 25 degrees C, respectively. This is contrary to the situation on the isostructural alpha-TiO2 (rutile), apparently because of the difference in electronegativity between Ti and Sn. MD simulations and speciation calculations indicated considerable differences in the speciation of Na+ and Rb+, despite the similarities in overall charging. Adsorbed sodium ions are almost exclusively found in bidentate surface complexes, whereas adsorbed rubidium ions form comparable numbers of bidentate and tetradentate complexes. Also, the distribution of adsorbed Na+ between the different complexes shows a considerable dependence on the surface charge density (pH), whereas the distribution of adsorbed Rb+ is almost independent of pH. A surface complexation model (SCM) capable of accurately describing both the measured surface charge and the MD-predicted speciation of adsorbed Na+/Rb+ was formulated. According to the SCM, the deprotonated terminal group (SnOH(-0.40)) and the protonated bridging group (Sn2OH+0.36) dominate the surface speciation over the entire pH range of this study (2.7-10). The complexation of medium cations increases significantly with

Effects of selective lingual gustatory deafferentation on suprathreshold taste intensity discrimination of NaCl in rats.

PubMed

Colbert, Connie L; Garcea, Mircea; Spector, Alan C

2004-12-01

In rats, chorda tympani nerve transection (CTX) greatly increases the detection threshold of sodium chloride (NaCl) and severely disrupts salt discriminability. Here it is shown that CTX has surprisingly little effect, if any, on suprathreshold intensity discrimination. Glossopharyngeal nerve transection (GLX), which has no reported effect on salt sensibility, also did not affect performance. Rats were tested in a 2-response, operant taste intensity discrimination task. Difference thresholds for CTX rats were only slightly higher (-0.15 log/10 unit) than those for GLX and sham-transected rats, when 0.05 M served as the standard, and did not significantly differ when 0.1 M NaCl was the standard. Although the perceived intensity of NaCl might be reduced by CTX, input from remaining taste nerves sufficiently maintains the relative discriminability of suprathreshold NaCl concentrations.

Thiazide diuretics directly induce osteoblast differentiation and mineralized nodule formation by targeting a NaCl cotransporter in bone

PubMed Central

Dvorak, Melita M; De Joussineau, Cyrille; Carter, D Howard; Pisitkun, Trairak; Knepper, Mark A; Gamba, Gerardo; Kemp, Paul J; Riccardi, Daniela

2008-01-01

Thiazide diuretics are used, worldwide, as the first-choice drug for patients with uncomplicated hypertension. In addition to their anti-hypertensive actions, they increase bone mineral density and reduce the prevalence of fractures, indicating that thiazides may have a role in the management of postmenopausal osteoporosis. Traditionally, the bone-protective effects of thiazides have been attributed to an increase in renal calcium reabsorption, secondary to the inhibition of the sodium chloride cotransporter, NCC, expressed in the kidney distal tubule. Whether thiazides exert a direct osteoanabolic effect independently of their renal action is controversial. Here we demonstrate that freshly frozen sections of human and rat bone express NCC, principally in bone-forming cells, the osteoblasts. In primary and established culture models of osteoblasts, fetal rat calvarial (FRC) and human MG63 cells, NCC protein is virtually absent in proliferating cells while its expression is dramatically increased during differentiation. Thiazides directly stimulate the production of osteoblast markers, runt-related transcription factor 2 (runx2) and osteopontin, in the absence of a proliferative effect. Using overexpression/knockdown studies in FRC cells, we show that thiazides, but not loop diuretics, increase mineralized nodule formation acting on NCC. Overall, our study demonstrates that thiazides stimulate osteoblast differentiation and bone mineral formation independently of their renal actions. In addition to their use as part of a therapeutic treatment plan for elderly, hypertensive individuals, our discovery opens up the possibility that bone-specific drug targeting by thiazides may be developed for the prevention and treatment of osteoporosis in the patient population as a whole. PMID:17656470

Chronic Metabolic Acidosis Activates Renal Tubular Sodium Chloride Cotransporter through Angiotension II-dependent WNK4-SPAK Phosphorylation Pathway

PubMed Central

Fang, Yu-Wei; Yang, Sung-Sen; Cheng, Chih-Jen; Tseng, Min-Hua; Hsu, Hui-Min; Lin, Shih-Hua

2016-01-01

The mechanism by which chronic metabolic acidosis (CMA) regulates sodium (Na+)-chloride (Cl−) cotransporter (NCC) in the renal distal convoluted tubules remains unexplored. We examined the role of STE20/SPS1-related proline/alanine-rich kinase (SPAK) and with-no-lysine kinase 4 (WNK4) on expression of NCC in mouse models of CMA. CMA was induced by NH4Cl in wild type mice (WTA mice), SPAK, and WNK4 knockout mice. The quantities of Ncc mRNA, expression of total NCC, phosphorylated (p)-NCC, SPAK and WNK4 in the kidneys as well as NCC inhibition with hydrochlorothiazide and Na+ balance were evaluated. Relative to WT mice, WTA mice had similar levels of Ncc mRNA, but increased expression of total and p-NCC, SPAK, and WNK4 and an exaggerated response to hydrochlorothiazide which could not be observed in SPAK or WNK4 knockout mice with CMA. In WTA mice, increased plasma renin activity, aldosterone and angiotensin II concentrations accompanied by a significantly negative Na+ balance. High Na+ diet abolished the enhanced NCC expression in WTA mice. Furthermore, an angiotensin II type 1 receptor blocker rather than a mineralocorticoid receptor antagonist exerted a marked inhibition on Na+ reabsorption and NCC phosphorylation in WTA mice. CMA increases WNK4-SPAK-dependent NCC phosphorylation and appears to be secondary to previous natriuresis with volume-dependent angiotensin II activation. PMID:26728390

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brock, T.A.; Brugnara, C.; Canessa, M.

The authors have characterized a Na/sup +/-K/sup +/-Cl/sup -/ cotransporter in vascular endothelial cells (EC) cultured from different blood vessels and species that is inhibited by the diuretics furosemide and bumentanide. Inward /sup 86/Rb influx transported by the Na/sup +/-K/sup +/ pump in cultured EC from bovine and pig aorta, bovine vena cava, and baboon cephalic vein but not in human umbilical or saphenous vein EC. External Na/sup +/ or Cl/sup -/-stimulated, ouabain-insensitive /sup 86/Rb influx is equal to furosemide or bumetanide-sensitive /sup 86/Rb influx. Ouabain-insensitive /sup 22/Na influx is also partially inhibited by these drugs and stimulated by increasingmore » external K/sup +/ or Cl/sup -/. Net Na/sup +/ extrusion occurs via the Na/sup +/-K/sup +/-Cl/sup -/ cotransporter in the absence of external K/sup +/, whereas net Na/sup +/ influx occurs at higher external K/sup +/. Maximal concentrations (100 nM) of bradykinin and vasopressin increase the initial rate of bumetanide-sensitive /sup 86/Rb influx by approx.60 and 70%. Addition of either ethyleneglycol-bis(..beta..-aminotethylether)-N,N'-tetraacetic acid or LaCl/sub 3/ (to block calcium influx) prevents bradykinin-stimulated /sup 86/Rb influx. When intracellular calcium is elevated using ionomycin (100 nM), a Ca/sup 2 +/ionophore, bumetanide-sensitive /sup 86/Rb influx increases approx.twofold. In contrast, isoproterenol (100 ..mu..M) and forskolin (50 /sup +/M), adenylate cyclase stimulators, decrease furosemide-sensitive /sup 86/Rb influx. Thus in certain types of cultured EC, a Na/sup +/-K/sup +/-Cl/sup -/ cotransporter mediates a fraction of K/sup +/ influx quantitatively as important as the Na/sup +/-K/sup +/ pump (ouabain-sensitive /sup 86/Rb influx) and appears to be modulated by Ca/sup 2 +/ and cyclic nucleotides.« less

Pressure induced structural phase transition from NaCl-type (B1) to CsCl-type (B2) structure in sodium chloride

NASA Astrophysics Data System (ADS)

Jain, Aayushi; Dixit, R. C.

2018-05-01

Pressure induced structural phase transition of NaCl-type (B1) to CsCl-type (B2) structure in Sodium Chloride NaCl are presented. An effective interionic interaction potential (EIOP) with long range Coulomb, van der Waals (vdW) interaction and the short-range repulsive interaction upto second-neighbor ions within the Hafemeister and Flygare approach with modified ionic charge is reported here. The reckon value of the phase transition pressure (Pt) and the magnitude of the discontinuity in volume at the transition pressure are compatible as compared with reported data. The variations of elastic constants and their combinations with pressure follow ordered behavior. The present approach has also succeeded in predicting the Born and relative stability criteria.

A comparative study of functional properties of normal and wooden breast broiler chicken meat with NaCl addition.

PubMed

Xing, Tong; Zhao, Xue; Han, Minyi; Cai, Linlin; Deng, Shaolin; Zhou, Guanghong; Xu, Xinglian

2017-09-01

The selection of broilers for augmented growth rate and breast has brought about wooden-breast (WB) muscle abnormalities, which caused substantial economic losses. The objective of this study was to compare water holding capacity, water mobility and distribution, salt-soluble protein (SSP) content, and protein profiles of normal and WB chicken meat with different additions of NaCl. Thirty WB and 30 normal chicken breasts were selected from a deboning line of a major Chinese processing plant at 2 to 3 h post mortem. Two different meat batters were formulated to 150 mg/g meat protein and different NaCl contents (0%, 1%, 2%, 3%, and 4%). Results indicated that as NaCl contents increased, the cooking loss of meat batters decreased (P < 0.05). Increasing the NaCl content to 3% or more increased the solubility of myofibrillar protein and the extraction of SSPs, which resulted in the improving of cooking yield. Over a range of salt concentrations, normal and WB meat showed different protein profiles, with myosin heavy chain exhibiting a higher intensity at ≥3% salt level. Low-field nuclear magnetic resonance (LF-NMR)revealed an increased T22 and higher P22 in raw WB meat compared to normal meat (P < 0.05). Regarding the meat batters, WB meat batters had reduced T21 and lower immobilized water proportions at low NaCl contents (<2%). After heating, T2 shifted towards higher relaxation times with increasing NaCl contents in meat gels. Meat gels prepared from WB had a lower proportion of water within the myofibrillar protein matrix and a greater proportion of exuded bulk water at NaCl contents <3% (P < 0.05), while at higher NaCl contents the difference was eliminated, thus improving water retention capacity. In conclusion, for raw meat, meat batters and gels, water distribution and mobility of WB exhibited significant differences compared to normal meat. The addition of NaCl affected water mobility and distributions in meat batters, with a level of 3% NaCl eliminating the

Low-temperature glasslike properties in (NaCl)1-x(NaCN)x

NASA Astrophysics Data System (ADS)

Watson, Susan K.; Pohl, R. O.

1995-04-01

Thermal conductivity, internal friction, transverse sound velocity (60 mK to 300 K), and specific-heat data (100 mK to 40 K) for (NaCl)1-x(NaCN)x (x=0, 0.025, 0.05, 0.1, 0.76, 1) show a progression from crystalline to glasslike behavior as the CN- concentration is increased from 0 to 76 %. The evolution of glasslike properties is compared to that in other crystals in which glasslike properties evolve with increasing disorder, e.g., (KBr)1-x(KCN)x and Ba1-xLaxF2-x. For (KBr)1-x(KCN)x, Sethna and Chow have shown that as the concentration of the almost freely rotating CN- ions is increased the average potential barrier for CN- reorientation also increases through elastic quadrupolar interactions. For x~0.5, only a small density of low-energy states is left, which equals that observed in structural glasses. In Ba1-xLaxF2-x, on the other hand, the crystal field for small doping x is so large that no atomic motion occurs at low temperatures. (NaCl)1-x(NaCN)x is shown to represent an intermediate case, in that the crystal field is non-negligible at small x, yet glasslike low-energy excitations indicative of very small potential barrier heights evolve with increasing x. It is argued that random internal strains cause a decrease of the barrier heights in these crystals, which lead to the low-energy excitations. It is proposed that random strains have a similar effect in other disordered crystals as in Ba1-xLaxF2-x, which for small x show no low-energy mobile states, yet which for large x become glasslike.

Cumulative effect of nitrogen and sulphur on Brassica juncea L. genotypes under NaCl stress.

PubMed

Siddiqui, Manzer H; Mohammad, Firoz; Khan, M Masrooor A; Al-Whaibi, Mohamed H

2012-01-01

In the present study, N and S assimilation, antioxidant enzymes activity, and yield were studied in N and S-treated plants of Brassica juncea (L.) Czern. & Coss. (cvs. Chuutki and Radha) under salt stress. The treatments were given as follows: (1) NaCl(90) mM+N(0)S(0) mg kg(-1) sand (control), (2) NaCl(90) mM+N(60)S(0) mg kg(-1) sand, (3) NaCl(90) mM+N(60)S(20) mg kg(-1) sand, (4) NaCl(90) mM+N(60)S(40) mg kg(-1) sand, and (5) NaCl(90) mM+N(60)S(60) mg kg(-1) sand. The combined application of N (60 mg kg(-1) sand) and S (40 mg kg(-1) sand) proved beneficial in alleviating the adverse effect of salt stress on growth attributes (shoot length plant(-1), fresh weight plant(-1), dry weight plant(-1), and area leaf(-1)), physio-biochemical parameters (carbonic anhydrase activity, total chlorophyll, adenosine triphosphate-sulphurylase activity, leaf N, K and Na content, K/Na ratio, activity of nitrate reductase, nitrite reductase, glutamine synthetase, glutamate synthase, catalase, superoxide dismutase, ascorbate peroxidase and glutathione reductase, and content of glutathione and ascorbate), and yield attributes (pods plant(-1), seeds pod(-1), and seed yield plant(-1)). Therefore, it is concluded that combined application of N and S induced the physiological and biochemical mechanisms of Brassica. The stimulation of antioxidant enzymes activity and its synergy with N and S assimilation may be one of the important mechanisms that help the plants to tolerate the salinity stress and resulted in an improved yield.

Osmolality- and Na+ -dependent effects of hyperosmotic NaCl solution on contractile activity and Ca2+ cycling in rat ventricular myocytes.

PubMed

Ricardo, Rafael A; Bassani, Rosana A; Bassani, José W M

2008-01-01

Hypertonic NaCl solutions have been used for small-volume resuscitation from hypovolemic shock. We sought to identify osmolality- and Na(+)-dependent components of the effects of the hyperosmotic NaCl solution (85 mOsm/kg increment) on contraction and cytosolic Ca(2+) concentration ([Ca(2+)](i)) in isolated rat ventricular myocytes. The biphasic change in contraction and Ca(2+) transient amplitude (decrease followed by recovery) was accompanied by qualitatively similar changes in sarcoplasmic reticulum (SR) Ca(2+) content and fractional release and was mimicked by isosmotic, equimolar increase in extracellular [Na(+)] ([Na(+)](o)). Raising osmolality with sucrose, however, augmented systolic [Ca(2+)](i) monotonically without change in SR parameters and markedly decreased contraction amplitude and diastolic cell length. Functional SR inhibition with thapsigargin abolished hyperosmolality effects on [Ca(2+)](i). After 15-min perfusion, both hyperosmotic solutions slowed mechanical relaxation during twitches and [Ca(2+)](i) decline during caffeine-evoked transients, raised diastolic and systolic [Ca(2+)](i), and depressed systolic contractile activity. These effects were greater with sucrose solution, and were not observed after isosmotic [Na(+)](o) increase. We conclude that under the present experimental conditions, transmembrane Na(+) redistribution apparently plays an important role in determining changes in SR Ca(2+) mobilization, which markedly affect contractile response to hyperosmotic NaCl solutions and attenuate the osmotically induced depression of contractile activity.

Effect of salts (NaCl and Na2CO3) on callus and suspension culture of Stevia rebaudiana for Steviol glycoside production.

PubMed

Gupta, Pratibha; Sharma, Satyawati; Saxena, Sanjay

2014-03-01

Steviol glycosides are natural non-caloric sweeteners which are extracted from the leaves of Stevia rebaudiana plant. Present study deals the effect of salts (NaCl and Na2CO3) on callus and suspension culture of Stevia plant for steviol glycoside (SGs) production. Yellow-green and compact calli obtained from in vitro raised Stevia leaves sub-cultured on MS medium supplemented with 2.0 mg l(-1) NAA and different concentrations of NaCl (0.05-0.20%) and Na2CO3 (0.0125-0.10%) for 2 weeks, and incubated at 24 ± 1 °C and 22.4 μmol m(-2) s(-1) light intensity provided by white fluorescent tubes for 16 h. Callus and suspension biomass cultured on salts showed less growth as well as browning of medium when compared with control. Quantification of SGs content in callus culture (collected on 15th day) and suspension cultures (collected at 10th and 15th days) treated with and without salts were analyzed by HPLC. It was found that abiotic stress induced by the salts increased the concentration of SGs significantly. In callus, the quantity of SGs got increased from 0.27 (control) to 1.43 and 1.57% with 0.10% NaCl, and 0.025% Na2CO3, respectively. However, in case of suspension culture, the same concentrations of NaCl and Na2CO3 enhanced the SGs content from 1.36 (control) to 2.61 and 5.14%, respectively, on the 10th day.

Characteristics of injury and recovery of net NO3- transport of barley seedlings from treatments of NaCl

NASA Technical Reports Server (NTRS)

Klobus, G.; Ward, M. R.; Huffaker, R. C.

1988-01-01

The nature of the injury and recovery of nitrate uptake (net uptake) from NaCl stress in young barley (Hordeum vulgare L, var CM 72) seedlings was investigated. Nitrate uptake was inhibited rapidly by NaCl, within 1 minute after exposure to 200 millimolar NaCl. The duration of exposure to saline conditions determined the time of recovery of NO3- uptake from NaCl stress. Recovery was dependent on the presence of NO3- and was inhibited by cycloheximide, 6-methylpurine, and cerulenin, respective inhibitors of protein, RNA, and sterol/fatty acid synthesis. These inhibitors also prevented the induction of the NO3- uptake system in uninduced seedlings. Uninduced seedlings exhibited endogenous NO3- transport activity that appeared to be constitutive. This constitutive activity was also inhibited by NaCl. Recovery of constitutive NO3- uptake did not require the presence of NO3-.

[Different NaCl-dependence of the circadian CO2-gas-exchange of some halophil growing coastal plants].

PubMed

Treichel, Siegfried; Bauer, Peter

1974-03-01

CO 2 -exchange, diurnal changes in malate- and ion concentrations of the halophytes Carpobrotus edulis, Crithmum maritimum, Mesembryanthemum nodiflorum, Salicornia fruticosa, Suaeda maritima, and Trifolium fragiferum were investigated after culture at different NaCl concentrations. In Carp. edulis and Mes. nodiflorum the diurnal rhythm of CO 2 -exchange is in accordance with that of crassulacean acid metabolism (CAM), in Sal. fruticosa, Crithm. maritimum, Suaeda maritima, and Trif. fragiferum with that of Benson-Calvin metabolism (C 3 ). Malate concentration and CO 2 uptake in the sap latter group are not influenced. On the other hand, Carp. edulis and Mes. nodiflorum show an accumulation of malate during the night, which can be interpreted as a further indication of CAM.The two species most resistant to NaCl, Carp. edulis and Sal. fruticosa, greatly differ very much in their NaCl content. NaCl concentration in Salicornia is four times higher than in Carpobrotus.The different metabolic properties studied might be of ecological importance for the plants in their natural habitats. The effect of NaCl on metabolic processes is discussed.

NaCl and osmolarity produce different responses in organum vasculosum of the lamina terminalis neurons, sympathetic nerve activity and blood pressure.

PubMed

Kinsman, Brian J; Browning, Kirsteen N; Stocker, Sean D

2017-09-15

Changes in extracellular osmolarity stimulate thirst and vasopressin secretion through a central osmoreceptor; however, central infusion of hypertonic NaCl produces a greater sympathoexcitatory and pressor response than infusion of hypertonic mannitol/sorbitol. Neurons in the organum vasculosum of the lamina terminalis (OVLT) sense changes in extracellular osmolarity and NaCl. In this study, we discovered that intracerebroventricular infusion or local OVLT injection of hypertonic NaCl increases lumbar sympathetic nerve activity, adrenal sympathetic nerve activity and arterial blood pressure whereas equi-osmotic mannitol/sorbitol did not alter any variable. In vitro whole-cell recordings demonstrate the majority of OVLT neurons are responsive to hypertonic NaCl or mannitol. However, hypertonic NaCl stimulates a greater increase in discharge frequency than equi-osmotic mannitol. Intracarotid or intracerebroventricular infusion of hypertonic NaCl evokes a greater increase in OVLT neuronal discharge frequency than equi-osmotic sorbitol. Collectively, these novel data suggest that subsets of OVLT neurons respond differently to hypertonic NaCl versus osmolarity and subsequently regulate body fluid homeostasis. These responses probably reflect distinct cellular mechanisms underlying NaCl- versus osmo-sensing. Systemic or central infusion of hypertonic NaCl and other osmolytes readily stimulate thirst and vasopressin secretion. In contrast, central infusion of hypertonic NaCl produces a greater increase in arterial blood pressure (ABP) than equi-osmotic mannitol/sorbitol. Although these responses depend on neurons in the organum vasculosum of the lamina terminalis (OVLT), these observations suggest OVLT neurons may sense or respond differently to hypertonic NaCl versus osmolarity. The purpose of this study was to test this hypothesis in Sprague-Dawley rats. First, intracerebroventricular (icv) infusion (5 μl/10 min) of 1.0 m NaCl produced a significantly greater

Covering surface nanobubbles with a NaCl nanoblanket.

PubMed

Berkelaar, Robin P; Zandvliet, Harold J W; Lohse, Detlef

2013-09-10

By letting a NaCl aqueous solution of low (0.01 M) concentration evaporate on a highly oriented pyrolytic graphite (HOPG) surface, it is possible to form a thin film of salt. However, pre-existing surface nanobubbles prevent the homogeneous coverage of the surface with the salt, keeping the footprint areas on the substrate pristine. Comparing the surface nanobubbles in the salt solution with their associated footprint after drying, provides information on the shrinkage of nanobubbles during the hours-long process of drying the liquid film. At a slightly higher NaCl concentration and thus salt layer thickness, the nanobubbles are covered with a thin blanket of salt. Once the liquid film has evaporated until a water film remains that is smaller than the height of the nanobubbles, the blanket of salt cracks and unfolds into a flower-like pattern of salt flakes that is located at the rim of the nanobubble footprint. The formation of a blanket of salt covering the nanobubbles is likely to considerably or even completely block the gas out-flux from the nanobubble, partially stabilizing the nanobubbles against dissolution.

NaCl osmotic perturbation can modulate hydration control in rabbit cornea.

PubMed

Ruberti, Jeffrey W; Klyce, Stephen D

2003-03-01

The corneal endothelium transports solute from the stroma to the aqueous humor, maintaining corneal hydration. Currently, little is known about how this active transport system is controlled. The purpose of this study is to investigate in greater detail the corneal response to small NaCl osmotic perturbations using a more refined automatic thickness measurement system in a search for response signatures of transport control. Adult New Zealand White rabbit corneas were debrided of their epithelium, excised and mounted in perfusion chambers. The endothelium, thus isolated, was bathed in isotonic Glutathione Bicarbonate Ringer's (GBR) solution and the bare anterior stroma was covered with silicone oil. Following stabilization in isotonic GBR, the endothelial perfusate was altered by +/-15 mOsm or+/-45 mOsm for 1 hr and 45 min by addition or removal of NaCl and returned (reversal) to GBR for 1 hr and 45 min. An enhanced, automatic scanning specular microscope monitored stromal thickness. The effective membrane transport coefficients were determined from the stromal thickness vs. time curves using an established numerical model of corneal hydration dynamics. It was found that the small (+/-15 mOsm) NaCl perturbations of the rabbit corneal endothelium resulted in a rapid trans-endothelial stromal volume control response that was not reversible after return to GBR. Long after the expected dissipation of the induced transients, this thickness 'controlling' response ultimately resulted in a sustained net thinning of 14 microm following the hypotonic perturbation and reversal, and a net swelling of 16 microm following the hypertonic perturbation and reversal. Model calculations indicated that the change induced by the perturbation could be explained by an immediate and persistent reduction of the passive endothelial NaCl permeability by 26% for the -15 mOsm perturbation compared to the +15 mOsm perturbation. This change persisted even after return to GBR. In contrast, the

Growth and cellular ion content of a salt-sensitive symbiotic system Azolla pinnata-Anabaena azollae under NaCl stress.

PubMed

Rai, Vandna; Sharma, Naveen Kumar; Rai, Ashwani K

2006-09-01

Salinity, at a concentration of 10 mM NaCl affected the growth of Azolla pinnata-Anabaena azollae association and became lethal at 40 mM. Plants exposed up to 30 mM NaCl exhibited longer roots than the control, especially during the beginning of incubation. Average root number in plants exposed to 10 and 20 mM NaCl remained almost the same as in control. A further rise in NaCl concentration to 30 mM reduced the root number, and roots shed off at 40 mM NaCl. Presence of NaCl in the nutrient solution increased the cellular Na+ of the intact association exhibiting differential accumulation by individual partners, while it reduced the cellular Ca2+ level. However, cellular K+ content did not show significant change. Cellular Na+ based on fresh weight of respective individual partners (host tissues and cyanobiont) remained higher in the host tissues than the cyanobiont, while reverse was true for K+ and Ca2+ contents. The contribution of A. azollae in the total cellular ion content of the association was a little because of meagre contribution of the cyanobiont mass (19-21%). High salt sensitivity of Azolla-Anabaena complex is due to an inability of the association to maintain low Na+ and high Ca2+ cellular level.

Hydrogen Generation from Al-NiCl2/NaBH4 Mixture Affected by Lanthanum Metal

PubMed Central

Qiang Sun, Wen; Fan, Mei-Qiang; Fei, Yong; Pan, Hua; Wang, Liang Liang; Yao, Jun

2012-01-01

The effect of La on Al/NaBH4 hydrolysis was elaborated in the present paper. Hydrogen generation amount increases but hydrogen generation rate decreases with La content increasing. There is an optimized composition that Al-15 wt% La-5 wt% NiCl2/NaBH4 mixture (Al-15 wt% La-5 wt% NiCl2/NaBH4 weight ratio, 1 : 3) has 126 mL g−1 min−1 maximum hydrogen generation rate and 1764 mL g−1 hydrogen generation amount within 60 min. The efficiency is 88%. Combined with NiCl2, La has great effect on NaBH4 hydrolysis but has little effect on Al hydrolysis. Increasing La content is helpful to decrease the particle size of Al-La-NiCl2 in the milling process, which induces that the hydrolysis byproduct Ni2B is highly distributed into Al(OH)3 and the catalytic reactivity of Ni2B/Al(OH)3 is increased therefore. But hydrolysis byproduct La(OH)3 deposits on Al surface and leads to some side effect. The Al-La-NiCl2/NaBH4 mixture has good stability in low temperature and its hydrolytic performance can be improved with increasing global temperature. Therefore, the mixture has good safety and can be applied as on board hydrogen generation material. PMID:22619596

Hydrogen generation from Al-NiCl2/NaBH4 mixture affected by lanthanum metal.

PubMed

Sun, Wen Qiang; Fan, Mei-Qiang; Fei, Yong; Pan, Hua; Wang, Liang Liang; Yao, Jun

2012-01-01

The effect of La on Al/NaBH(4) hydrolysis was elaborated in the present paper. Hydrogen generation amount increases but hydrogen generation rate decreases with La content increasing. There is an optimized composition that Al-15 wt% La-5 wt% NiCl(2)/NaBH(4) mixture (Al-15 wt% La-5 wt% NiCl(2)/NaBH(4) weight ratio, 1 : 3) has 126 mL g(-1 )min(-1) maximum hydrogen generation rate and 1764 mL g(-1) hydrogen generation amount within 60 min. The efficiency is 88%. Combined with NiCl(2), La has great effect on NaBH(4) hydrolysis but has little effect on Al hydrolysis. Increasing La content is helpful to decrease the particle size of Al-La-NiCl(2) in the milling process, which induces that the hydrolysis byproduct Ni(2)B is highly distributed into Al(OH)(3) and the catalytic reactivity of Ni(2)B/Al(OH)(3) is increased therefore. But hydrolysis byproduct La(OH)(3) deposits on Al surface and leads to some side effect. The Al-La-NiCl(2)/NaBH(4) mixture has good stability in low temperature and its hydrolytic performance can be improved with increasing global temperature. Therefore, the mixture has good safety and can be applied as on board hydrogen generation material.

Cell growth and water relations of the halophyte, Atriplex nummularia L., in response to NaCl.

PubMed

Casas, A M; Bressan, R A; Hasegawa, P M

1991-06-01

Growth reduction or cessation is an initial response of Atriplex nummularia L. cells to NaCl. However, A. nummularia L. cells that are adapted to 342 and 428 mM NaCl are capable of sustained growth in the presence of salt. Cells that are adapted to NaCl exhibit a reduced rate of division compared to unadapted cells. Unlike salt adapted cells of the glycophyte Nicotiana tabacum L., A. nummularia L. cells do not exhibit reduced rate of cell expansion after adaptation. However, the cell expansion rate of unadapted A. nummularia L. cells is considerably slower than that of unadapted glycophyte cells and this normally low rate of cell expansion may contribute to the enhanced capacity of the halophyte to tolerate salt. Turgor of NaCl adapted cells was equivalent to unadapted cells indicating that the cells of the halophyte do not respond to salt by osmotic "over adjustment" as reported for the glycophyte tobacco (Binzel et al. 1985, Plant Physiol. 79:118-125).

Salt exclusion and mycorrhizal symbiosis increase tolerance to NaCl and CaCl2 salinity in ‘Siam Queen’ basil

USDA-ARS?s Scientific Manuscript database

A study was conducted to evaluate the effects of salinity on growth and nutrient uptake in basil (Ocimum basilicum L.). Plants were fertilized with a complete nutrient solution and exposed to no, low, or moderate levels of salinity from NaCl or CaCl2. Plants in the control and moderate salinity tre...

Prolactin 177, prolactin 188, and extracellular osmolality independently regulate the gene expression of ion transport effectors in gill of Mozambique tilapia.

PubMed

Inokuchi, Mayu; Breves, Jason P; Moriyama, Shunsuke; Watanabe, Soichi; Kaneko, Toyoji; Lerner, Darren T; Grau, E Gordon; Seale, Andre P

2015-11-15

This study characterized the local effects of extracellular osmolality and prolactin (PRL) on branchial ionoregulatory function of a euryhaline teleost, Mozambique tilapia (Oreochromis mossambicus). First, gill filaments were dissected from freshwater (FW)-acclimated tilapia and incubated in four different osmolalities, 280, 330, 380, and 450 mosmol/kg H2O. The mRNA expression of Na(+)/K(+)-ATPase α1a (NKA α1a) and Na(+)/Cl(-) cotransporter (NCC) showed higher expression with decreasing media osmolalities, while Na(+)/K(+)/2Cl(-) cotransporter 1a (NKCC1a) and PRL receptor 2 (PRLR2) mRNA levels were upregulated by increases in media osmolality. We then incubated gill filaments in media containing ovine PRL (oPRL) and native tilapia PRLs (tPRL177 and tPRL188). oPRL and the two native tPRLs showed concentration-dependent effects on NCC, NKAα1a, and PRLR1 expression; Na(+)/H(+) exchanger 3 (NHE3) expression was increased by 24 h of incubation with tPRLs. Immunohistochemical observation showed that oPRL and both tPRLs maintained a high density of NCC- and NKA-immunoreactive ionocytes in cultured filaments. Furthermore, we found that tPRL177 and tPRL188 differentially induce expression of these ion transporters, according to incubation time. Together, these results provide evidence that ionocytes of Mozambique tilapia may function as osmoreceptors, as well as directly respond to PRL to modulate branchial ionoregulatory functions. Copyright © 2015 the American Physiological Society.

Gene amplification at a locus encoding a putative Na+/H+ antiporter confers sodium and lithium tolerance in fission yeast.

PubMed Central

Jia, Z P; McCullough, N; Martel, R; Hemmingsen, S; Young, P G

1992-01-01

We have identified a new locus, sodium 2 (sod2) based on selection for increased LiCl tolerance in fission yeast, Schizosaccharomyces pombe. Tolerant strains have enhanced pH-dependent Na+ export capacity and sodium transport experiments suggest that the gene encodes an Na+/H+ antiport. The predicted sod2 gene product can be placed in the broad class of transporters which possess 12 hydrophobic transmembrane domains. The protein shows some sequence similarity to the human and bacterial Na+/H+ antiporters. Overexpression of sod2 increased Na+ export capacity and conferred sodium tolerance. Osmotolerance was not affected and sod2 cells were unaffected for growth in K+. In a sod2 disruption strain cells were incapable of exporting sodium. They were hypersensitive to Na+ or Li+ and could not grow under conditions that approximate pH7. The sod2 gene amplification could be selected stepwise and the degree of such amplification correlated with the level of Na+ or Li+ tolerance. Images PMID:1314171

Calculation of the vapor-saturated liquidus for the NaCl-CO2-H2O system

USGS Publications Warehouse

Barton, P.B.; I-Ming, C.

1993-01-01

The polybaric liquidus surface for the H2O-rich corner of the NaCl-CO2-H2O ternary is calculated, relying heavily on 1. (1) a Henry's law equation for CO2 in brines (modified from Drummond, 1981), 2. (2) the assumption that the contributions of dissolved NaCl and CO2 in lowering the activity of H2O are additive, and 3. (3) data on the CO2 clathrate solid solution (nominally CO2 ?? 7.3H2O, but ranging from 5.75 to 8 or 9 H2O) from Bozzo et al. (1975). The variation with composition of the activity of CO2??7.3H2O, or any other composition within the clathrate field, is small, thereby simplifying the calculations appreciably. Ternary invariant points are 1. (1) ternary eutectic at -21.5??C, with ice + clathrate + hydrohalite NaCl-??H2O + brine mNaCl = 5.15, mco2 = 0.22 + vapor Ptotal ??? Pco2 = 5.7 atm; 2. (2) peritectic at -9.6??C, with clathrate + hydrohalite + liquid CO2 + brine mNaCl = 5.18, mco2 = 0.55 + vapor (Ptotal ??? Pco2 = 26.47 atm); and 3. (3) peritectic slightly below +0.1 ??C, with halite + hydrohalite + liquid CO2 + brine (mNaCl ??? 5.5, mco2 ??? 0.64) + vapor (Ptotal ??? Pco2 ??? 34 atm). CO2 isobars have been contoured on the ternary liquidus and also on the 25??C isotherm. An important caveat regarding the application of this information to the interpretation of the freezing-thawing behavior of fluid inclusions is that metastable behavior is a common characteristic of the clathrate. ?? 1993.

Cephradine as corrosion inhibitor for copper in 0.9% NaCl solution

NASA Astrophysics Data System (ADS)

Tasić, Žaklina Z.; Petrović Mihajlović, Marija B.; Radovanović, Milan B.; Simonović, Ana T.; Antonijević, Milan M.

2018-05-01

The effect of (6R,7R)-7-[[(2R)-2-amino-2-cyclohexa-1,4-dien-1-ylacetyl]amino]-3-methyl-8-oxo-5-thia-1-azobicyclo[4.2.0]oct-2-ene-2-carboxylic acid (cephradine) on corrosion behavior of copper in 0.9% NaCl solution was investigated. The electrochemical methods including the open circuit potential measurements, potentiodynamic polarization and electrochemical impedance spectroscopy measurements, scanning electron microscopy with energy dispersive X-ray spectroscopy and quantum chemical calculations were used for this investigation. According to the results obtained by potentiodynamic polarization, cephradine acts as mixed type inhibitor. Also, the results obtained by electrochemical impedance spectroscopy indicate that cephradine provides good copper protection in 0.9% NaCl solution. The inhibition efficiency of cephradine increases with increasing its concentration. The scanning electron microscopy with energy dispersive X-ray spectroscopy confirms that a protective layer is formed on the copper surface due to the adsorption of cephradine on the active sites on the copper surface. Adsorption of cephradine in 0.9% NaCl solution follows the Langmuir adsorption isotherm. Quantum chemical calculations are in agreement with results obtained by electrochemical measurements.

Phase diagram of the LiNO3-NaNO3-NaCl-Sr(NO3)2 salt system

NASA Astrophysics Data System (ADS)

Rasulov, A. I.; Gasanaliev, A. M.; Mamedova, A. K.; Gamataeva, B. Yu.

2015-04-01

The phase diagram of the quaternary LiNO3-NaNO3-NaCl-Sr(NO3)2 system is studied by means of differential thermal analysis, and the compositions and crystallization temperatures of nonvariant equilibrium phases are revealed. The temperature dependence of conductivity in eutectic and peritectic salt compositions is investigated.

Gastrointestinal processing of Na+, Cl-, and K+ during digestion: implications for homeostatic balance in freshwater rainbow trout.

PubMed

Bucking, Carol; Wood, Chris M

2006-12-01

The role of the gastrointestinal tract in maintaining ionic homeostasis during digestion, as well as the relative contribution of the diet for providing electrolytes, has been generally overlooked in many aquatic species. An experimental diet that contained an inert reference marker (lead-glass beads) was used to quantify the net transport of Na(+), K(+), and Cl(-) during the digestion and absorption of a single meal (3% ration) by freshwater rainbow trout (Oncorhynchus mykiss). Secretion of Cl(-) into the stomach peaked at 8 and 12 h following feeding at a rate of 1.1 mmol.kg(-1).h(-1), corresponding to a theoretical pH of 0.6 in the secreted fluid (i.e., 240 mmol/l HCl). The majority ( approximately 90%) of dietary Na(+) and K(+) was absorbed in the stomach, whereas subsequent large fluxes of Na(+) and Cl(-) into the anterior intestine corresponded to a large flux of water previously observed. The estimated concentration of Na(+) in fluids secreted into the anterior intestine was approximately 155 mmol/l, equivalent to reported hepatic bile values, whereas the estimated concentration of Cl(-) ( approximately 285 mmol/l) suggested seepage of HCl acid from the stomach in advance of the chyme front. Net absorption of K(+) in the stomach occurred following the cessation of Cl(-) secretion, providing indirect evidence of K(+) involvement with HCl acid production. Overall, 80-90% of the K(+) and Cl(-) contents of the meal were absorbed on a net basis, whereas net Na(+) absorption was negligible. Chyme-to-plasma ion concentration gradients were often opposed to the direction of ion transport, especially for Na(+) and Cl(-).

Acclimation to NaCl and light stress of heterotrophic Chlamydomonas reinhardtii for lipid accumulation.

PubMed

Fan, Jianhua; Zheng, Lvhong

2017-09-01

Salt stress has been proven very effective in enhancing the lipid content among many photoautotrophically grown microalgae species including marine and freshwater algae. Nevertheless, its effect on heterotrophic grown cells and lipid accumulation is scarcely known. This study sought to demonstrate a new train of thought for cost-effective biofuels production by heterotrophic culture of Chlamydomonas reinhardtii coupling with subsequent salt and light stress. NaCl treatments (25-200 mM) gradually suppressed the cell growth. After one day's acclimation, the cells restored slow growth with light supplement (200 μmol/m2/s) in low salt concentration (0-50 mM). However, high concentration of NaCl (200 mM) dose caused permanent damage, with over 47% cells death after 3 days treatment. The highest lipid content of 35.8% and lipid productivity of 28.6 mg/L/d were achieved by 50 mM NaCl stress and light treatment upon heterotrophic grown cells. Cells lost their green pigmentation and became yellowish under 100-200 mM NaCl conditions, whereas cells grown in 0-50 mM NaCl retained their dark-green pigmentation. Variable-to-maximum fluorescence ratio (Fv/Fm) and non-photochemical quenching (NPQ) value were markedly influenced under salt and light stress, indicating that severe inhibition of photosynthetic ability was occurred. Moreover, we further demonstrated the dynamic changes of cell growth and lipid accumulation would potentially be caused by the increase of intracellular redox state. To our knowledge, this study is the first instance in which C. reinhardtii was applied to oil accumulation by using combination of heterotrophic culture and multiple stress, and opened up a new territory for the further development of microalgae-based biofuels production. Copyright © 2017 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Luminescence upconversion under hydrostatic pressure in the 3d-metal systems Ti2+:NaCl and Ni2+:CsCdCl3

NASA Astrophysics Data System (ADS)

Wenger, Oliver S.; Salley, G. Mackay; Valiente, Rafael; Güdel, Hans U.

2002-06-01

We present a study of upconversion materials and processes under external hydrostatic pressure. The near-infrared to visible photon upconversion properties of Ti2+-doped NaCl and Ni2+-doped CsCdCl3 at 15 K are studied as a function of external hydrostatic pressure. It is found that in Ti2+:NaCl pressure can be used to switch on an efficient upconversion mechanism, which is inactive at ambient pressure, leading to an order-of-magnitude enhancement of the overall upconversion efficiency of this material. For Ni2+:CsCdCl3 it is demonstrated that upconversion luminescence excitation spectroscopy can be used to study the pressure dependence of excited state absorption transitions. The results demonstrate the ability to tune upconversion properties by altering the local crystal field of active ions, in addition to probing the pressure dependence of excited state absorption transitions via upconversion spectroscopy.

[Effects of NaCl stress on photosynthesis characteristics and fast chlorophyll fluorescence induction dynamics of Pistacia chinensis leaves].

PubMed

Li, Xu-Xin; Liu, Bing-Xiang; Guo, Zhi-Tao; Chang, Yue-Xia; He, Lei; Chen, Fang; Lu, Bing-She

2013-09-01

By using fast chlorophyll fluorescence induction dynamics analysis technique (JIP-test), this paper studied the photosynthesis characteristics and fast chlorophyll fluorescence induction dynamics of 1-year old Pistacia chinensis seedlings under the stress of NaCl at the concentrations 0% (CK), 0.15%, 0.3%, 0.45%, and 0.6%. With the increasing concentration of NaCl, the contents of Chl a, Chl b, and Chl (a+b) in the seedlings leaves decreased, the Chl a/b ratio decreased after an initial increase, and the carotenoid content increased. The net photosynthetic rate (P(n)) and stomatal conductance (g(s)) decreased gradually with increasing NaCl concentration. The decrease of P(n) was mainly attributed to the stomatal limitation when the NaCl concentration was lower than 0.3%, and to the non-stomatal limitation when the NaCl concentration was higher than 0.3%. The trapped energy flux per RC (TR0/CS0), electron transport flux per RC (ET0/CS0), density of RCs (RC/CS0), and yield or flux ratio (psi(0) or phi(E0)) decreased, but the absorption flux per CS (ABS/CS0) and the K phase (W(k)) and J phase (V) in the O-J-I-P chlorophyll fluorescence induction curves increased distinctly, indicating that NaCl stress damaged the leaf oxygen-evolving complex (OEC), donor sides, and PS II reaction centers. When the NaCl concentration reached 0.3%, the maximum photochemical efficiency (F(v)/F(m)) and performance index (PI(ABS)) decreased 17.7% and 36.6%, respectively, as compared with the control.

Forward flux sampling calculation of homogeneous nucleation rates from aqueous NaCl solutions.

PubMed

Jiang, Hao; Haji-Akbari, Amir; Debenedetti, Pablo G; Panagiotopoulos, Athanassios Z

2018-01-28

We used molecular dynamics simulations and the path sampling technique known as forward flux sampling to study homogeneous nucleation of NaCl crystals from supersaturated aqueous solutions at 298 K and 1 bar. Nucleation rates were obtained for a range of salt concentrations for the Joung-Cheatham NaCl force field combined with the Extended Simple Point Charge (SPC/E) water model. The calculated nucleation rates are significantly lower than the available experimental measurements. The estimates for the nucleation rates in this work do not rely on classical nucleation theory, but the pathways observed in the simulations suggest that the nucleation process is better described by classical nucleation theory than an alternative interpretation based on Ostwald's step rule, in contrast to some prior simulations of related models. In addition to the size of NaCl nucleus, we find that the crystallinity of a nascent cluster plays an important role in the nucleation process. Nuclei with high crystallinity were found to have higher growth probability and longer lifetimes, possibly because they are less exposed to hydration water.

Forward flux sampling calculation of homogeneous nucleation rates from aqueous NaCl solutions

NASA Astrophysics Data System (ADS)

Jiang, Hao; Haji-Akbari, Amir; Debenedetti, Pablo G.; Panagiotopoulos, Athanassios Z.

2018-01-01

We used molecular dynamics simulations and the path sampling technique known as forward flux sampling to study homogeneous nucleation of NaCl crystals from supersaturated aqueous solutions at 298 K and 1 bar. Nucleation rates were obtained for a range of salt concentrations for the Joung-Cheatham NaCl force field combined with the Extended Simple Point Charge (SPC/E) water model. The calculated nucleation rates are significantly lower than the available experimental measurements. The estimates for the nucleation rates in this work do not rely on classical nucleation theory, but the pathways observed in the simulations suggest that the nucleation process is better described by classical nucleation theory than an alternative interpretation based on Ostwald's step rule, in contrast to some prior simulations of related models. In addition to the size of NaCl nucleus, we find that the crystallinity of a nascent cluster plays an important role in the nucleation process. Nuclei with high crystallinity were found to have higher growth probability and longer lifetimes, possibly because they are less exposed to hydration water.

Coupled phase and aqueous species equilibrium of the H 2O-CO 2-NaCl-CaCO 3 system from 0 to 250 °C, 1 to 1000 bar with NaCl concentrations up to saturation of halite

NASA Astrophysics Data System (ADS)

Duan, Zhenhao; Li, Dedong

2008-10-01

A model is developed for the calculation of coupled phase and aqueous species equilibrium in the H 2O-CO 2-NaCl-CaCO 3 system from 0 to 250 °C, 1 to 1000 bar with NaCl concentrations up to saturation of halite. The vapor-liquid-solid (calcite, halite) equilibrium together with the chemical equilibrium of H +, Na +, Ca 2+, CaHCO3+, Ca(OH) +, OH -, Cl -, HCO3-, CO32-, CO 2(aq) and CaCO 3(aq) in the aqueous liquid phase as a function of temperature, pressure, NaCl concentrations, CO 2(aq) concentrations can be calculated, with accuracy close to those of experiments in the stated T- P- m range, hence calcite solubility, CO 2 gas solubility, alkalinity and pH values can be accurately calculated. The merit and advantage of this model is its predictability, the model was generally not constructed by fitting experimental data. One of the focuses of this study is to predict calcite solubility, with accuracy consistent with the works in previous experimental studies. The resulted model reproduces the following: (1) as temperature increases, the calcite solubility decreases. For example, when temperature increases from 273 to 373 K, calcite solubility decreases by about 50%; (2) with the increase of pressure, calcite solubility increases. For example, at 373 K changing pressure from 10 to 500 bar may increase calcite solubility by as much as 30%; (3) dissolved CO 2 can increase calcite solubility substantially; (4) increasing concentration of NaCl up to 2 m will increase calcite solubility, but further increasing NaCl solubility beyond 2 m will decrease its solubility. The functionality of pH value, alkalinity, CO 2 gas solubility, and the concentrations of many aqueous species with temperature, pressure and NaCl (aq) concentrations can be found from the application of this model. Online calculation is made available on www.geochem-model.org/models/h2o_co2_nacl_caco3/calc.php.

Variations of water's local-structure induced by solvation of NaCl

NASA Astrophysics Data System (ADS)

Gu, Bin; Zhang, Feng-Shou; Huang, Yu-Gai; Fang, Xia

2010-03-01

The researches on the structure of water and its changes induced by solutes are of enduring interests. The changes of the local structure of liquid water induced by NaCl solute under ambient conditions are studied and presented quantitatively with some order parameters and visualized with 2-body and 3-body correlation functions. The results show that, after the NaCl are solvated, the translational order t of water is decreased for the suppression of the second hydration shells around H2O molecules; the tetrahedral order (q) of water is also decreased and its favorite distribution peak moves from 0.76 to 0.5. In addition, the orientational freedom k and the diffusion coefficient D of water molecules are reduced because of new formed hydrogen-bonding structures between water and solvated ions.

Essential role of the electroneutral Na+-HCO3- cotransporter NBCn1 in murine duodenal acid-base balance and colonic mucus layer build-up in vivo.

PubMed

Singh, Anurag Kumar; Xia, Weiliang; Riederer, Brigitte; Juric, Marina; Li, Junhua; Zheng, Wen; Cinar, Ayhan; Xiao, Fang; Bachmann, Oliver; Song, Penghong; Praetorius, Jeppe; Aalkjaer, Christian; Seidler, Ursula

2013-04-15

Duodenal epithelial cells need efficient defence strategies during gastric acidification of the lumen, while colonic mucosa counteracts damage by pathogens by building up a bacteria-free adherent mucus layer. Transport of HCO3(-) is considered crucial for duodenal defence against acid as well as for mucus release and expansion, but the transport pathways involved are incompletely understood. This study investigated the significance of the electroneutral Na(+)-HCO3(-) cotransporter NBCn1 for duodenal defence against acid and colonic mucus release. NBCn1 was localized to the basolateral membrane of duodenal villous enterocytes and of colonic crypt cells, with predominant expression in goblet cells. Duodenal villous enterocyte intracellular pH was studied before and during a luminal acid load by two-photon microscopy in exteriorized, vascularly perfused, indicator (SNARF-1 AM)-loaded duodenum of isoflurane-anaesthetized, systemic acid-base-controlled mice. Acid-induced HCO3(-) secretion was measured in vivo by single-pass perfusion and pH-stat titration. After a luminal acid load, NBCn1-deficient duodenocytes were unable to recover rapidly from intracellular acidification and could not respond adequately with protective HCO3(-) secretion. In the colon, build-up of the mucus layer was delayed, and a decreased thickness of the adherent mucus layer was observed, suggesting that basolateral HCO3(-) uptake is essential for optimal release of mucus. The electroneutral Na(+)-HCO3(-) cotransporter NBCn1 displays a differential cellular distribution in the murine intestine and is essential for HCO3(-)-dependent mucosal protective functions, such as recovery of intracellular pH and HCO3(-) secretion in the duodenum and secretion of mucus in the colon.

Tyrosine kinase inhibitors and immunosuppressants perturb the myo-inositol but not the betaine cotransporter in isotonic and hypertonic MDCK cells

PubMed Central

Atta, Mohamed G.; Dahl, Stephen C.; Kwon, H. Moo; Handler, Joseph S.

2008-01-01

Background The sodium/myo-inositol cotransporter (SMIT) and the betaine cotransporter (BGT1) are essential for the accumulation of myo-inositol and betaine, and hence cell survival in a hypertonic environment. The underlying molecular mechanism involves an increase in transcription of the SMIT and BGT1 genes through binding of a trans-acting factor to enhancer elements in the 5′ flanking region of both genes, resulting in increased mRNA abundance and increased activity of the cotransporters. Current evidence regarding transcriptional and post-transcriptional regulation indicates that both cotransporters are regulated in parallel. Methods To investigate the signal transduction of hypertonic stress, we examined the effect of tyrosine kinase inhibitors and immunosuppressants on the hypertonicity-induced activity of the two cotransporters in Madin-Darby canine kidney (MDCK) cells. Results None of the agents studied affected BGT1 activity in isotonic or hypertonic conditions. Treatment of MDCK cells with genistein, a tyrosine kinase inhibitor, increased SMIT activity in hypertonic but not isotonic conditions. The stimulation of SMIT by genistein was accompanied by a parallel increase in mRNA abundance. In contrast, treating cells with tyrphostin A23, another tyrosine kinase inhibitor, or cyclosporine A, an immunosuppressant, inhibited SMIT activity in hypertonic cells. FK506, another immunosuppressant, increased SMIT activity, but only in isotonic conditions. Conclusions These results provide the first evidence of divergent regulatory pathways modulating SMIT and BGT activity. PMID:10027932

Aqueous NaCl and CsCl Solutions Confined in Crystalline Slit-Shaped Silica Nanopores of Varying Degree of Protonation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ho, Tuan A.; Argyris, Dimitrios; Cole, David R.

2011-12-13

All-atom molecular dynamics simulations were conducted to study the dynamics of aqueous electrolyte solutions confined in slit-shaped silica nanopores of various degrees of protonation. Five degrees of protonation were prepared by randomly removing surface hydrogen atoms from fully protonated crystalline silica surfaces. Aqueous electrolyte solutions containing NaCl or CsCl salt were simulated at ambient conditions. In all cases, the ionic concentration was 1 M. The results were quantified in terms of atomic density distributions within the pores, and the self-diffusion coefficient along the direction parallel to the pore surface. We found evidence for ion-specific properties that depend on ion-surface, water-ion,more » and only in some cases ion-ion correlations. The degree of protonation strongly affects the structure, distribution, and the dynamic behavior of confined water and electrolytes. Cl -ions adsorb on the surface at large degrees of protonation, and their behavior does not depend significantly on the cation type (either Na + or Cs + ions are present in the systems considered). The cations show significant ion-specific behavior. Na + ions occupy different positions within the pore as the degree of protonation changes, while Cs + ions mainly remain near the pore center at all conditions considered. For a given degree of protonation, the planar self-diffusion coefficient of Cs + is always greater than that of Na + ions. The results are useful for better understanding transport under confinement, including brine behavior in the subsurface, with important applications such as environmental remediation.« less

Inhibition effect of sugar-based amphiphiles on eutectic formation in the freezing-thawing process of aqueous NaCl solution.

PubMed

Ogawa, Shigesaburo; Osanai, Shuichi

2007-04-01

DSC and simultaneous XRD-DSC measurements were carried out to clarify the interaction among the ingredients in a ternary aqueous solution composed of NaCl, a sugar-based amphiphile or free sugar, and water. Two aspects of the inhibition of eutectic formation were suggested through the addition of the sugar amphiphile. One was the retention of the glass state of the eutectic phase, and the other was the trapping of NaCl hydrate into the sugar moiety of the amphiphilic aggregate. The difference between the free sugar and the amphiphilic one in terms of the trapping of NaCl hydrate was attributable to their dissimilarity in the dissolution state. The results indicated that the free sugars in water could interact with NaCl hydrate on the basis of their various hydroxyl groups. On the other hand, the sugar-based amphiphiles generated a self-assembly aggregate in the system, and interacted with NaCl hydrate by a salting-in effect with their sugar moiety in the freezing-thawing process. It was confirmed that the number of sugar units played an important role in trapping NaCl hydrate in the system. The effects of the structural isomerism in the sugars were slight with regard to the inhibition of eutectic formation.

Changes in growth, carbon and nitrogen enzyme activity and mRNA accumulation in the halophilic microalga Dunaliella viridis in response to NaCl stress

NASA Astrophysics Data System (ADS)

Wang, Dongmei; Wang, Weiwei; Xu, Nianjun; Sun, Xue

2016-12-01

Many species of microalga Dunaliella exhibit a remarkable tolerance to salinity and are therefore ideal for probing the effects of salinity. In this work, we assessed the effects of NaCl stress on the growth, activity and mRNA level of carbon and nitrogen metabolism enzymes of D. viridis. The alga could grow over a salinity range of 0.44 mol L-1 to 3.00 mol L-1 NaCl, but the most rapid growth was observed at 1.00 mol L-1 NaCl, followed by 2.00 mol L-1 NaCl. Paralleling these growth patterns, the highest initial and total Rubisco activities were detected in the presence of 1.00 mol L-1 NaCl, decreasing to 37.33% and 26.39% of those values, respectively, in the presence of 3.00 mol L-1 NaCl, respectively. However, the highest extracellular carbonic anhydrase (CA) activity was measured in the presence of 2.00 mol L-1 NaCl, followed by 1.00 mol L-1 NaCl. Different from the two carbon enzymes, nitrate reductase (NR) activity showed a slight change under different NaCl concentrations. At the transcriptional level, the mRNAs of Rubisco large subunit ( rbcL), and small subunit ( rbcS), attained their highest abundances in the presence of 1.00 and 2.00 mol L-1 NaCl, respectively. The CA mRNA accumulation was induced from 0.44 mol L-1 to 3.00 mol L-1 NaCl, but the NR mRNA showed the decreasing tendency with the increasing salinity. In conclusion, the growth and carbon fixation enzyme of Rubisco displayed similar tendency in response to NaCl stress, CA was proved be salt-inducible within a certain salinity range and NR showed the least effect by NaCl in D. viridis.

The role of NaCl in flame chemistry, in the deposition process, and in its reactions with protective oxides as related to hot corrosion

NASA Technical Reports Server (NTRS)

Kohl, F. J.; Stearns, C. A.

1979-01-01

Sodium chloride is believed to be the primary source of turbine engine contamination that contributes to hot corrosion. The behavior of NaCl-containing aerosols ingested with turbine intake air is very complex; some of the NaCl may vaporize during combustion while some may remain as particulates. The NaCl can lead to Na2SO4 formation by several possible routes or it can contribute to corrosion directly. Hydrogen or oxygen atom reaction with NaCl(c) was shown to result in the release of Na(g). Gaseous NaCl in flames can be partially converted to gaseous Na2SO4 by homogeneous reactions. The remaining gaseous NaCl and other Na-containing molecules can act as sodium carriers for condensate deposition of Na2SO4 on cool surfaces. A frozen boundary layer theory was developed to predict the rates of deposition. The condensed phase NaCl can be converted directly to condensed Na2SO4 by reaction with sulfur oxides and O2. Reaction of gaseous NaCl with Cr2O3 results in the vapor phase transport of chromium by the formation of complex Cr-containing gaseous molecules. Similar gaseous complexes are formed with molybdenum. The presence of gaseous NaCl was shown to affect the oxidation kinetics of Ni-Cr alloys. It also causes changes in the surface morphology of Al2O3 scales formed on Al-containing alloys.

L-leucine, L-methionine, and L-phenylalanine share a Na(+)/K (+)-dependent amino acid transporter in shrimp hepatopancreas.

PubMed

Duka, Ada; Ahearn, Gregory A

2013-08-01

Hepatopancreatic brush border membrane vesicles (BBMV), made from Atlantic White shrimp (Litopenaeus setiferus), were used to characterize the transport properties of (3)H-L-leucine influx by these membrane systems and how other essential amino acids and the cations, sodium and potassium, interact with this transport system. (3)H-L-leucine uptake by BBMV was pH-sensitive and occurred against transient transmembrane concentration gradients in both Na(+)- and K(+)-containing incubation media, suggesting that either cation was capable of providing a driving force for amino acid accumulation. (3)H-L-leucine uptake in NaCl or KCl media were each three times greater in acidic pH (pH 5.5) than in alkaline pH (pH 8.5). The essential amino acid, L-methionine, at 20 mM significantly (p < 0.0001) inhibited the 2-min uptakes of 1 mM (3)H-L-leucine in both Na(+)- and K(+)-containing incubation media. The residual (3)H-L-leucine uptake in the two media were significantly greater than zero (p < 0.001), but not significantly different from each other (p > 0.05) and may represent an L-methionine- and cation-independent transport system. (3)H-L-leucine influxes in both NaCl and KCl incubation media were hyperbolic functions of [L-leucine], following the carrier-mediated Michaelis-Menten equation. In NaCl, (3)H-L-leucine influx displayed a low apparent K M (high affinity) and low apparent J max, while in KCl the transport exhibited a high apparent K M (low affinity) and high apparent J max. L-methionine or L-phenylalanine (7 and 20 mM) were competitive inhibitors of (3)H-L-leucine influxes in both NaCl and KCl media, producing a significant (p < 0.01) increase in (3)H-L-leucine influx K M, but no significant response in (3)H-L-leucine influx J max. Potassium was a competitive inhibitor of sodium co-transport with (3)H-L-leucine, significantly (p < 0.01) increasing (3)H-L-leucine influx K M in the presence of sodium, but having negligible effect on (3)H-L-leucine influx J

Hygroscopic Properties of Internally Mixed Particles Composed of NaCl and Water-Soluble Organic Acids

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ghorai, Suman; Wang, Bingbing; Tivanski, Alexei V.

Atmospheric aging of naturally emitted marine aerosol often leads to formation of internally mixed particles composed of sea salts and water soluble organic compounds of anthropogenic origin. Mixing of sea salt and organic components has profound effects on the evolving chemical composition and hygroscopic properties of the resulted particles, which are poorly understood. Here, we have studied chemical composition and hygroscopic properties of laboratory generated NaCl particles mixed with malonic acid (MA) and glutaric acid (GA) at different molar ratios using micro-FTIR spectroscopy and X-ray elemental microanalysis.Hygroscopic properties of inte rnally mixed NaCl and organic acid particles were distinctly differentmore » from pure components and varied significantly with the type and amount of organic compound present. Experimental results were in a good agreement with the AIM modeling calculations of gas/liquid/solid partitioning in studied systems. X-ray elemental microanalysis of particles showed that Cl/Na ratio decreased with increasing organic acid component in the particles with MA yielding lower ratios relative to GA. We attribute the depletion of chloride to the formation of Na-malonate and Na-glutarate salts resulted by HCl evaporation from dehydrating particles.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nauntofte, B.; Poulsen, J.H.

Stimulation-induced changes in Cl content and O2 consumption of collagenase-isolated rat parotid acini were measured. In <10 s, carbachol caused a net Cl efflux, corresponding to approx.50% of the Cl content, and increased the O2 uptake by 100%. The increase was inhibitable by ouabain and was dependent on the presence of extracellular CaS . Furosemide reduced the unstimulated TWCl uptake and prevented the reuptake of Cl after carbachol-induced release. This suggests that a cotransport system is operating in both the unstimulated and stimulated states. Furthermore, furosemide inhibited the stimulated ouabain-sensitive OS uptake. Raising intracellular CaS by the calcium ionophore A23187more » evoked the same pattern of Cl loss and O2 uptake as carboachol. Our results ae compatible with the following hypothesis. Carbachol raises intracellular CaS , causing an increased Cl permeability of the luminal membrane, resulting in a net Cl efflux. A subsequently enhanced influx of Cl and Na via a furosemide-sensitive cotransport system increases intracellular Na . This stimulates the Na -K -ATPase and thereby the OS consumption.« less

Solubility of KF and NaCl in water by molecular simulation.

PubMed

Sanz, E; Vega, C

2007-01-07

The solubility of two ionic salts, namely, KF and NaCl, in water has been calculated by Monte Carlo molecular simulation. Water has been modeled with the extended simple point charge model (SPC/E), ions with the Tosi-Fumi model and the interaction between water and ions with the Smith-Dang model. The chemical potential of the solute in the solution has been computed as the derivative of the total free energy with respect to the number of solute particles. The chemical potential of the solute in the solid phase has been calculated by thermodynamic integration to an Einstein crystal. The solubility of the salt has been calculated as the concentration at which the chemical potential of the salt in the solution becomes identical to that of the pure solid. The methodology used in this work has been tested by reproducing the results for the solubility of KF determined previously by Ferrario et al. [J. Chem. Phys. 117, 4947 (2002)]. For KF, it was found that the solubility of the model is only in qualitative agreement with experiment. The variation of the solubility with temperature for KF has also been studied. For NaCl, the potential model used predicts a solubility in good agreement with the experimental value. The same is true for the hydration chemical potential at infinite dilution. Given the practical importance of solutions of NaCl in water the model used in this work, whereas simple, can be of interest for future studies.

Role of rat sodium/phosphate cotransporters in the cell membrane transport of arsenate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Villa-Bellosta, Ricardo; Sorribas, Victor

2008-10-01

Inorganic arsenate (As{sup V}) is a common contaminant of underground water. Following oral exposure, it is assumed that As{sup V} is distributed and crosses cell membranes through inorganic phosphate (Pi) transporters. We have tested this hypothesis by studying the inhibition of rat Na/Pi cotransporters by As{sup V} in Xenopus laevis oocytes and in several rat tissues. The ubiquitously expressed type III Pi transporters (PiT-1 and PiT-2) showed a low affinity for As{sup V} (K{sub i} {approx} 3.8 mM), similar to the Pi transport system in aortic vascular smooth muscle cells (K{sub i} 1.5 mM). The type II renal isoforms, NaPi-IIamore » and NaPi-IIc, were also poorly inhibited by As{sup V} (K{sub i} {approx} 1 mM), similar to the Pi transport from kidney cortex brush-border membrane (BBM) vesicles. Conversely, the high-affinity intestinal transporter, NaPi-IIb, was very efficiently inhibited with a K{sub i} of 51 {mu}M, similar to the Pi transport from intestinal BBM vesicles. Taking into account the 1.1 mM Pi in blood and renal ultrafiltrate, and the nanomolar range of As{sup V} exposures, we have determined that the contribution by Na/Pi cotransporters to As{sup V} membrane transport is negligible, given that 10-15 mM As{sup V} would be necessary in these fluids to be significantly transported. Intestinal transport is an exception, because Pi competition is weak, thereby considering that its concentration in lumen mainly depends on low Pi levels from ingested fresh water, and because As{sup V} very efficiently inhibits Pi intestinal transport. Our data agree with current toxicokinetic knowledge, and they explain the asymmetric excretion of trivalent and pentavalent arsenic species into bile and urine.« less

Solubility of NaCl and KCl in aqueous HCl from 20 to 85°C

USGS Publications Warehouse

Potter, Robert W.; Clynne, Michael A.

1980-01-01

The solubilities of NaCl and KCl in aqueous HCl solutions were determined from 20 to 85°C at concentrations ranging from 0 to 20 g of HCl/100 g of solution. Equations are given that describe the solubilities over the range of conditions studied. For NaCl and KCl respectively measured solubilities show an average deviation from these equations of ??0.10 and ??0.08 g/100 g of saturated solution.

Integrated responses of Na+/HCO3- cotransporters and V-type H+-ATPases in the fish gill and kidney during respiratory acidosis.

PubMed

Perry, S F; Furimsky, M; Bayaa, M; Georgalis, T; Shahsavarani, A; Nickerson, J G; Moon, T W

2003-12-30

Using degenerate primers, followed by 3' and 5' RACE and "long" PCR, a continuous 4050-bp cDNA was obtained and sequenced from rainbow trout (Oncorhynchus mykiss) gill. The cDNA included an open reading frame encoding a deduced protein of 1088 amino acids. A BLAST search of the GenBank protein database demonstrated that the trout gene shared high sequence similarity with several vertebrate Na(+)/HCO(3)(-) cotransporters (NBCs) and in particular, NBC1. Protein alignment revealed that the trout NBC is >80% identical to vertebrate NBC1s and phylogenetic analysis provided additional evidence that the trout NBC is indeed a homolog of NBC1. Using the same degenerate primers, a partial cDNA (404 bp) for NBC was obtained from eel (Anguilla rostrata) kidney. Analysis of the tissue distribution of trout NBC, as determined by Northern blot analysis and real-time PCR, indicated high transcript levels in several absorptive/secretory epithelia including gill, kidney and intestine and significant levels in liver. NBC mRNA was undetectable in eel gill by real-time PCR. In trout, the levels of gill NBC1 mRNA were increased markedly during respiratory acidosis induced by exposure to hypercarbia; this response was accompanied by a transient increase in branchial V-type H(+)-ATPase mRNA levels. Assuming that the branchial NBC1 is localised to basolateral membranes of gill cells and operates in the influx mode (HCO(3)(-) and Na(+) entry into the cell), it would appear that in trout, the expression of branchial NBC1 is transcriptionally regulated to match the requirements of gill pHi regulation rather than to match trans-epithelial HCO(3)(-) efflux requirements for systemic acid-base balance. By analogy with mammalian systems, NBC1 in the kidney probably plays a role in the tubular reabsorption of both Na(+) and HCO(3)(-). During periods of respiratory acidosis, levels of renal NBC1 mRNA increased (after a transient reduction) in both trout and eel, presumably to increase HCO(3

Regulators of Slc4 bicarbonate transporter activity.

PubMed

Thornell, Ian M; Bevensee, Mark O

2015-01-01

The Slc4 family of transporters is comprised of anion exchangers (AE1-4), Na(+)-coupled bicarbonate transporters (NCBTs) including electrogenic Na/bicarbonate cotransporters (NBCe1 and NBCe2), electroneutral Na/bicarbonate cotransporters (NBCn1 and NBCn2), and the electroneutral Na-driven Cl-bicarbonate exchanger (NDCBE), as well as a borate transporter (BTR1). These transporters regulate intracellular pH (pHi) and contribute to steady-state pHi, but are also involved in other physiological processes including CO2 carriage by red blood cells and solute secretion/reabsorption across epithelia. Acid-base transporters function as either acid extruders or acid loaders, with the Slc4 proteins moving HCO(-) 3 either into or out of cells. According to results from both molecular and functional studies, multiple Slc4 proteins and/or associated splice variants with similar expected effects on pHi are often found in the same tissue or cell. Such apparent redundancy is likely to be physiologically important. In addition to regulating pHi, a HCO(-) 3 transporter contributes to a cell's ability to fine tune the intracellular regulation of the cotransported/exchanged ion(s) (e.g., Na(+) or Cl(-)). In addition, functionally similar transporters or splice variants with different regulatory profiles will optimize pH physiology and solute transport under various conditions or within subcellular domains. Such optimization will depend on activated signaling pathways and transporter expression profiles. In this review, we will summarize and discuss both well-known and more recently identified regulators of the Slc4 proteins. Some of these regulators include traditional second messengers, lipids, binding proteins, autoregulatory domains, and less conventional regulators. The material presented will provide insight into the diversity and physiological significance of multiple members within the Slc4 gene family.

Influence of NaCl Concentrations on Coagulation, Temperature, and Electrical Conductivity Using a Perfusion Radiofrequency Ablation System: An Ex Vivo Experimental Study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aube, Christophe, E-mail: ChAube@chu-angers.fr; Schmidt, Diethard; Brieger, Jens

2007-02-15

Purpose. To determine, by means of an ex vivo study, the effect of different NaCl concentrations on the extent of coagulation obtained during radiofrequency (RF) ablation performed using a digitally controlled perfusion device. Method. Twenty-eight RF ablations were performed with 40 W for 10 min using continuous NaCl infusion in fresh excised bovine liver. For perfusion, NaCl concentrations ranging from 0 (demineralized water) to 25% were used. Temperature, the amount of energy, and the dimensions of thermal-induced white coagulation were assessed for each ablation. These parameters were compared using the nonparametric Mann-Whitney test. Correlations were calculated according to the Spearmanmore » test. Results. RF ablation performed with 0.9% to 25% concentrations of NaCl produced a mean volume of coagulation of 30.7 {+-} 3.8 cm{sup 3}, with a mean short-axis diameter of 3.6 {+-} 0.2 cm. The mean amount of energy was 21,895 {+-} 1,674 W and the mean temperature was 85.4 {+-} 12.8 deg. C. Volume of coagulation, short-axis diameter, and amount of energy did not differ significantly among NaCl concentrations (p > 0.5). A correlation was found between the NaCl concentration and the short-axis diameter of coagulation (r = 0.64) and between the NaCl concentration and the mean temperature (r = 0.67), but not between the NaCl concentration and volume of coagulation. Conclusion. In an ex vivo model, continuous perfusion with high NaCl concentrations does not significantly improve the volume of thermal-induced coagulation. This may be because the use of a low-power generator cannot sufficiently exploit the potential advantage of better tissue conductivity provided by NaCl perfusion.« less

Effect of concentration of hyaluronic acid and NaCl on corrosion behavior of 316L austenitic stainless steel

NASA Astrophysics Data System (ADS)

Bansod, Ankur V.; Khobragade, Nilay N.; Giradkar, Karansagar V.; Patil, Awanikumar P.

2017-11-01

Due to low cost and easily available material, 316L stainless steel (SS) is used for biomedical implants. The electrochemical corrosion behavior of 316L (SS) was studied as a function of the concentration of simulated biological fluid (hyaluronic acid), the influence of Cl- and the combined effect of NaCl and hyaluronic acid (HA). For the electrochemical tests, potentiodynamic polarization test and electrochemical impedance spectroscopy (EIS) were undertaken. With the increase in HA concentration, corrosion rate increases. Whereas, with the addition of NaCl to HA the solution, the corrosion resistance of the sample was enhanced. Also, in pure NaCl solution, the corrosion current density (i corr) increased as compared to bare HA and HA  +  NaCl. This is due to the adhesion property of the HA on the sample surface. EIS result agrees with the findings of potentiodynamic polarization tests. X-ray photoelectron spectroscopy (XPS) was executed to analyze the passive film formed in the solution of HA and NaCl on 316L SS. XPS spectra confirms the formation of the passive film containing chromium oxide and hydroxides. Also, the formation of MoO2 helps in improving better corrosion resistance. The peak of nitrogen was observed in the sample immersed in HA solution. Scanning electron microscope (SEM) was carried out to analyze the surface morphology.

Consensus on the solubility of NaCl in water from computer simulations using the chemical potential route.

PubMed

Benavides, A L; Aragones, J L; Vega, C

2016-03-28

The solubility of NaCl in water is evaluated by using three force field models: Joung-Cheatham for NaCl dissolved in two different water models (SPC/E and TIP4P/2005) and Smith Dang NaCl model in SPC/E water. The methodology based on free-energy calculations [E. Sanz and C. Vega, J. Chem. Phys. 126, 014507 (2007)] and [J. L. Aragones et al., J. Chem. Phys. 136, 244508 (2012)] has been used, except, that all calculations for the NaCl in solution were obtained by using molecular dynamics simulations with the GROMACS package instead of homemade MC programs. We have explored new lower molalities and made longer runs to improve the accuracy of the calculations. Exploring the low molality region allowed us to obtain an analytical expression for the chemical potential of the ions in solution as a function of molality valid for a wider range of molalities, including the infinite dilute case. These new results are in better agreement with recent estimations of the solubility obtained with other methodologies. Besides, two empirical simple rules have been obtained to have a rough estimate of the solubility of a certain model, by analyzing the ionic pairs formation as a function of molality and/or by calculating the difference between the NaCl solid chemical potential and the standard chemical potential of the salt in solution.

Photoresponsive Release from Azobenzene-Modified Single Cubic Crystal NaCl/Silica Particles

DOE PAGES

Jiang, Xingmao; Liu, Nanguo; Assink, Roger A.; ...

2011-01-01

Azobenzene ligands were uniformly anchored to the pore surfaces of nanoporous silica particles with single crystal NaCl using 4-(3-triethoxysilylpropylureido)azobenzene (TSUA). The functionalization delayed the release of NaCl significantly. The modified particles demonstrated a photocontrolled release by trans/cis isomerization of azobenzene moieties. The addition of amphiphilic solvents, propylene glycol (PG), propylene glycol propyl ether (PGPE), and dipropylene glycol propyl ether (DPGPE) delayed the release in water, although the wetting behavior was improved and the delay is the most for the block molecules with the longest carbon chain. The speedup by UV irradiation suggests a strong dependence of diffusion on the switchablemore » pore size. TGA, XRD, FTIR, and NMR techniques were used to characterize the structures.« less

Paradoxical activation of the sodium chloride cotransporter (NCC) without hypertension in kidney deficient in a regulatory subunit of Na,K-ATPase, FXYD2.

PubMed

Arystarkhova, Elena; Ralph, Donna L; Liu, Yi Bessie; Bouley, Richard; McDonough, Alicia A; Sweadner, Kathleen J

2014-12-01

Na,K-ATPase generates the driving force for sodium reabsorption in the kidney. Na,K-ATPase functional properties are regulated by small proteins belonging to the FXYD family. In kidney FXYD2 is the most abundant: it is an inhibitory subunit expressed in almost every nephron segment. Its absence should increase sodium pump activity and promote Na(+) retention, however, no obvious renal phenotype was detected in mice with global deletion of FXYD2 (Arystarkhova et al. 2013). Here, increased total cortical Na,K-ATPase activity was documented in the Fxyd2(-/-) mouse, without increased α1β1 subunit expression. We tested the hypothesis that adaptations occur in distal convoluted tubule (DCT), a major site of sodium adjustments. Na,K-ATPase immunoreactivity in DCT was unchanged, and there was no DCT hypoplasia. There was a marked activation of thiazide-sensitive sodium chloride cotransporter (NCC; Slc12a3) in DCT, predicted to increase Na(+) reabsorption in this segment. Specifically, NCC total increased 30% and NCC phosphorylated at T53 and S71, associated with activation, increased 4-6 fold. The phosphorylation of the closely related thick ascending limb (TAL) apical NKCC2 (Slc12a1) increased at least twofold. Abundance of the total and cleaved (activated) forms of ENaC α-subunit was not different between genotypes. Nonetheless, no elevation of blood pressure was evident despite the fact that NCC and NKCC2 are in states permissive for Na(+) retention. Activation of NCC and NKCC2 may reflect an intracellular linkage to elevated Na,K-ATPase activity or a compensatory response to Na(+) loss proximal to the TAL and DCT. © 2014 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of the American Physiological Society and The Physiological Society.

Crevice corrosion - NaCl concentration map for grade-2 titanium at elevated temperature

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tsujikawa, Shigeo; Kojima, Yoichi

1993-12-31

The repassivation potential, ER, for metal/metal-crevice of Commercially Pure Titanium, C.P.Ti, was determined in NaCl solutions at temperatures up to 250C. The ER has its least noble value near 100C and becomes more noble as the temperature increases. As shown in previous research, the shrinkage of the repassivation region should continue with increasing temperatures. However, in conducting this same experiment at temperatures higher than 100C, an examination of the NaCl concentration - temperature - crevice corrosion map verifies that the repassivation region began to expand again when the temperature exceeded 140C. This expansion continued as the temperature continued to increase.

Domain structure of human complement C4b extends with increasing NaCl concentration: implications for its regulatory mechanism.

PubMed

Fung, Ka Wai; Wright, David W; Gor, Jayesh; Swann, Marcus J; Perkins, Stephen J

2016-12-01

During the activation of complement C4 to C4b, the exposure of its thioester domain (TED) is crucial for the attachment of C4b to activator surfaces. In the C4b crystal structure, TED forms an Arg 104 -Glu 1032 salt bridge to tether its neighbouring macroglobulin (MG1) domain. Here, we examined the C4b domain structure to test whether this salt bridge affects its conformation. Dual polarisation interferometry of C4b immobilised at a sensor surface showed that the maximum thickness of C4b increased by 0.46 nm with an increase in NaCl concentration from 50 to 175 mM NaCl. Analytical ultracentrifugation showed that the sedimentation coefficient s 20,w of monomeric C4b of 8.41 S in 50 mM NaCl buffer decreased to 7.98 S in 137 mM NaCl buffer, indicating that C4b became more extended. Small angle X-ray scattering reported similar R G values of 4.89-4.90 nm for C4b in 137-250 mM NaCl. Atomistic scattering modelling of the C4b conformation showed that TED and the MG1 domain were separated by 4.7 nm in 137-250 mM NaCl and this is greater than that of 4.0 nm in the C4b crystal structure. Our data reveal that in low NaCl concentrations, both at surfaces and in solution, C4b forms compact TED-MG1 structures. In solution, physiologically relevant NaCl concentrations lead to the separation of the TED and MG1 domain, making C4b less capable of binding to its complement regulators. These conformational changes are similar to those seen previously for complement C3b, confirming the importance of this salt bridge for regulating both C4b and C3b. © 2016 The Author(s).

Na/Cl molar ratio changes during a salting cycle and its application to the estimation of sodium retention in salted watersheds.

PubMed

Sun, Hongbing; Huffine, Maria; Husch, Jonathan; Sinpatanasakul, Leeann

2012-08-01

Using soil column experiments and data from natural watersheds, this paper analyzes the changes in Na/Cl molar ratios during a salting cycle of aqueous-soil systems. The soil column experiments involved introducing NaCl salt at various initial concentrations into multiple soil columns. At the start of a salting cycle in the column experiments, sodium was adsorbed more than chloride due to cation exchange processes. As a result, the initial Na/Cl molar ratio in column effluent was lower than 1, but increased thereafter. One-dimensional PHREEQC geochemical transport simulations also were conducted to further quantify these trends under more diverse scenarios. The experimentally determined Na/Cl molar ratio pattern was compared to observations in the annual salting cycle of four natural watersheds where NaCl is the dominant applied road deicing salt. Typically, Na/Cl molar ratios were low from mid-winter to early spring and increased after the bulk of the salt was flushed out of the watersheds during the summer, fall and early winter. The established relationship between the Na/Cl molar ratios and the amount of sodium retention derived from the column experiments and computer simulations present an alternative approach to the traditional budget analysis method for estimating sodium retention when the experimental and natural watershed patterns of Na/Cl molar ratio change are similar. Findings from this study enhance the understanding of sodium retention and help improve the scientific basis for future environmental policies intended to suppress the increase of sodium concentrations in salted watersheds. Copyright © 2012 Elsevier B.V. All rights reserved.

Halopriming of seeds imparts tolerance to NaCl and PEG induced stress in Vigna radiata (L.) Wilczek varieties.

PubMed

Jisha, K C; Puthur, Jos T

2014-07-01

The investigation was carried out to study the effect of halopriming on NaCl and polyethylene glycol-6000 (PEG-6000) induced stress tolerance potential of three Vigna radiata (L.) Wilczek varieties, with varied abiotic stress tolerance potential. Halopriming is a seed priming technique in which the seeds were soaked in various salt solutions (in this study NaCl was used). The results of the study indicated that the application of stresses (both NaCl and PEG) induced retardation of growth attributes (measured in terms of shoot length, fresh weight, dry weight) and decrease in physiological attributes like total chlorophyll content, metabolites, photosynthetic and mitochondrial activity of the seedlings in all three V. radiata (L.) varieties. However, halopriming of the seeds could reduce the extent of decrease in these biological attributes. NaCl and PEG stress also caused increase in MDA content (a product of membrane lipid peroxidation) in all the varieties studied and this increase was significantly minimized under halopriming. From the present investigation it was evident that among the green gram varieties studied, Pusa Vishal, a NaCl tolerant variety showed enhanced tolerance to NaCl and PEG induced stress, when the seeds were subjected to halopriming followed by Pusa Ratna (stress sensitive variety). Pusa 9531 (drought tolerant variety) also showed positive halopriming effects but it was less significant when compared to other two varieties. It could be concluded that halopriming improved the drought and salinity stress tolerance potential of all varieties and it was significantly higher in the Pusa Vishal as compared to Pusa 9531 and Pusa Ratna.

High NaCl- and urea-induced posttranslational modifications that increase glycerophosphocholine by inhibiting GDPD5 phosphodiesterase.

PubMed

Topanurak, Supachai; Ferraris, Joan D; Li, Jinxi; Izumi, Yuichiro; Williams, Chester K; Gucek, Marjan; Wang, Guanghui; Zhou, Xiaoming; Burg, Maurice B

2013-04-30

Glycerophosphocholine (GPC) is high in cells of the renal inner medulla where high interstitial NaCl and urea power concentration of the urine. GPC protects inner medullary cells against the perturbing effects of high NaCl and urea by stabilizing intracellular macromolecules. Degradation of GPC is catalyzed by the glycerophosphocholine phosphodiesterase activity of glycerophosphodiester phosphodiesterase domain containing 5 (GDPD5). We previously found that inhibitory posttranslational modification (PTM) of GDPD5 contributes to high NaCl- and urea-induced increase of GPC. The purpose of the present studies was to identify the PTM(s). We find at least three such PTMs in HEK293 cells: (i) Formation of a disulfide bond between C25 and C571. High NaCl and high urea increase reactive oxygen species (ROS). The ROS increase disulfide bonding between GDPD5-C25 and -C571, which inhibits GDPD5 activity, as supported by the findings that the antioxidant N-acetylcysteine prevents high NaCl- and urea-induced inhibition of GDPD5; GDPD5-C25S/C571S mutation or over expression of peroxiredoxin increases GDPD5 activity; H2O2 inhibits activity of wild type GDPD5, but not of GDPD5-C25S/C571S; and peroxiredoxin is relatively low in the renal inner medulla where GPC is high. (ii) Dephosphorylation of GDPD5-T587. GDPD5 threonine 587 is constitutively phosphorylated. High NaCl and high urea dephosphorylate GDPD5-T587. Mutation of GDPD5-T587 to alanine, which cannot be phosphorylated, decreases GPC-PDE activity of GDPD5. (iii) Alteration at an unknown site mediated by CDK1. Inhibition of CDK1 protein kinase reduces GDE-PDE activity of GDPD5 without altering phosphorylation at T587, and CDK1/5 inhibitor reduces activity of GDPD5- C25S/C571S-T587A.

High NaCl- and urea-induced posttranslational modifications that increase glycerophosphocholine by inhibiting GDPD5 phosphodiesterase

PubMed Central

Topanurak, Supachai; Ferraris, Joan D.; Li, Jinxi; Izumi, Yuichiro; Williams, Chester K.; Gucek, Marjan; Wang, Guanghui; Zhou, Xiaoming; Burg, Maurice B.

2013-01-01

Glycerophosphocholine (GPC) is high in cells of the renal inner medulla where high interstitial NaCl and urea power concentration of the urine. GPC protects inner medullary cells against the perturbing effects of high NaCl and urea by stabilizing intracellular macromolecules. Degradation of GPC is catalyzed by the glycerophosphocholine phosphodiesterase activity of glycerophosphodiester phosphodiesterase domain containing 5 (GDPD5). We previously found that inhibitory posttranslational modification (PTM) of GDPD5 contributes to high NaCl- and urea-induced increase of GPC. The purpose of the present studies was to identify the PTM(s). We find at least three such PTMs in HEK293 cells: (i) Formation of a disulfide bond between C25 and C571. High NaCl and high urea increase reactive oxygen species (ROS). The ROS increase disulfide bonding between GDPD5-C25 and -C571, which inhibits GDPD5 activity, as supported by the findings that the antioxidant N-acetylcysteine prevents high NaCl- and urea-induced inhibition of GDPD5; GDPD5-C25S/C571S mutation or over expression of peroxiredoxin increases GDPD5 activity; H2O2 inhibits activity of wild type GDPD5, but not of GDPD5-C25S/C571S; and peroxiredoxin is relatively low in the renal inner medulla where GPC is high. (ii) Dephosphorylation of GDPD5-T587. GDPD5 threonine 587 is constitutively phosphorylated. High NaCl and high urea dephosphorylate GDPD5-T587. Mutation of GDPD5-T587 to alanine, which cannot be phosphorylated, decreases GPC-PDE activity of GDPD5. (iii) Alteration at an unknown site mediated by CDK1. Inhibition of CDK1 protein kinase reduces GDE-PDE activity of GDPD5 without altering phosphorylation at T587, and CDK1/5 inhibitor reduces activity of GDPD5- C25S/C571S-T587A. PMID:23589856

Mitigation of NaCl Stress by Arbuscular Mycorrhizal Fungi through the Modulation of Osmolytes, Antioxidants and Secondary Metabolites in Mustard (Brassica juncea L.) Plants

PubMed Central

Sarwat, Maryam; Hashem, Abeer; Ahanger, Mohammad A.; Abd_Allah, Elsayed F.; Alqarawi, A. A.; Alyemeni, Mohammed N.; Ahmad, Parvaiz; Gucel, Salih

2016-01-01

Present work was carried out to investigate the possible role of arbuscular mycorrhizal fungi (AMF) in mitigating salinity-induced alterations in Brassica juncea L. Exposure to NaCl stress altered the morphological, physio-biochemical attributes, antioxidant activity, secondary metabolites and phytohormones in the mustard seedlings. The growth and biomass yield, leaf water content, and total chlorophyll content were decreased with NaCl stress. However, AMF-inoculated plants exhibited enhanced shoot and root length, elevated relative water content, enhanced chlorophyll content, and ultimately biomass yield. Lipid peroxidation and proline content were increased by 54.53 and 63.47%, respectively with 200 mM NaCl concentration. Further increase in proline content and decrease in lipid peroxidation was observed in NaCl-treated plants inoculated with AMF. The antioxidants, superoxide dismutase, ascorbate peroxidase, glutathione reductase, and reduced glutathione were increased by 48.35, 54.86, 43.85, and 44.44%, respectively, with 200 mM NaCl concentration. Further increase in these antioxidants has been observed in AMF-colonized plants indicating the alleviating role of AMF to salinity stress through antioxidant modulation. The total phenol, flavonoids, and phytohormones increase with NaCl treatment. However, NaCl-treated plants colonized with AMF showed further increase in the above parameters except ABA, which was reduced with NaCl+AMF treatment over the plants treated with NaCl alone. Our results demonstrated that NaCl caused negative effect on B. juncea seedlings; however, colonization with AMF enhances the NaCl tolerance by reforming the physio-biochemical attributes, activities of antioxidant enzymes, and production of secondary metabolites and phytohormones. PMID:27458462

Influence of NaCl on Growth, Proline, and Phosphoenolpyruvate Carboxylase Levels in Mesembryanthemum crystallinum Suspension Cultures 1

PubMed Central

Thomas, John C.; De Armond, Richard L.; Bohnert, Hans J.

1992-01-01

The facultative halophyte Mesembryanthemum crystallinum responds to salt stress by increasing the levels of phosphoenolpyruvate carboxylase (PEPCase) and other enzymes associated with Crassulacean acid metabolism. A more common response to salt stress in sensitive and tolerant species, including M. crystallinum, is the accumulation of proline. We have established M. crystallinum suspension cultures to investigate whether both these salt-induced responses occur at the cellular level. Leaf-and root-derived cultures maintain 5% of the total soluble amino acids as proline. Cell culture growth slows upon addition of 400 millimolar NaCl, and proline levels increase to 40% of the total soluble amino acids. These results suggest a functional salt-stress and response program in Mesembryanthemum cells. Suspension cultures grown with or without 400 millimolar NaCl have PEPCase levels that compare with those from roots and unstressed leaves. The predominant protein cross-reacting with an anti-PEPCase antibody corresponds to 105 kilodaltons (apparent molecular mass), whereas a second species of approximately 110 kilodaltons is present at low levels. In salt-stressed leaves, the 110 kilodalton protein is more prevalent. Levels of mRNA for both ppc1 (salt stress induced in leaves) and ppc2 (constitutive) genes in salt-treated suspensions cultures are equal to unstressed leaves, and only twice the levels found in untreated suspension cultures. Whereas cells accumulate proline in response to NaCl, PEPCase protein amounts remain similar in salt-treated and untreated cultures. The induction upon salt stress of the 110 kilodalton PEPCase protein and other Crassulacean acid metabolism enzymes in organized tissues is not observed in cell culture and may depend on tissue-dependent or photoautotrophy-dependent programs. ImagesFigure 4Figure 5 PMID:16668687

Preparation of Ferrotitanium Alloys by Electrolysis-Assisted Calciothermic Reduction of Ilmenite in Equimolar CaCl2-NaCl Electrolyte: Effect of Calcium Oxide

NASA Astrophysics Data System (ADS)

Zhou, Zhongren; Zhang, Yingjie; Hua, Yixin; Xu, Cunying; Dong, Peng; Zhang, Qibo; Wang, Ding

2018-04-01

The effect of CaO content on the preparation of ferrotitanium alloys from ilmenite with the method of the electrolysis-assisted calciothermic reduction has been investigated by use of ilmenite powders as raw materials that positions them next to the cathodic molybdenum plate, equimolar CaCl2-NaCl molten salt with 2-7 mol.% CaO as electrolyte and graphite as anode at 700°C with cell voltage of 2.8 V under argon atmosphere. It is demonstrated that increasing the reactant CaO content is beneficial to the calciothermic reduction of ilmenite and the intermediate CaTiO3. Experimental results also show that after 14 h of calciothermic reduction process, the products are ferrotitanium alloys and the specific energy consumption is only about 10.21 kWh kg-1 when adding 5 mol.% CaO into equimolar CaCl2-NaCl molten salt and approximately 14.40 kWh kg-1 when CaO content is increased to 7 mol.%.

New saliva secretion model based on the expression of Na+-K+ pump and K+ channels in the apical membrane of parotid acinar cells.

PubMed

Almássy, János; Siguenza, Elias; Skaliczki, Marianna; Matesz, Klara; Sneyd, James; Yule, David I; Nánási, Péter P

2018-04-01

The plasma membrane of parotid acinar cells is functionally divided into apical and basolateral regions. According to the current model, fluid secretion is driven by transepithelial ion gradient, which facilitates water movement by osmosis into the acinar lumen from the interstitium. The osmotic gradient is created by the apical Cl - efflux and the subsequent paracellular Na + transport. In this model, the Na + -K + pump is located exclusively in the basolateral membrane and has essential role in salivary secretion, since the driving force for Cl - transport via basolateral Na + -K + -2Cl - cotransport is generated by the Na + -K + pump. In addition, the continuous electrochemical gradient for Cl - flow during acinar cell stimulation is maintained by the basolateral K + efflux. However, using a combination of single-cell electrophysiology and Ca 2+ -imaging, we demonstrate that photolysis of Ca 2+ close to the apical membrane of parotid acinar cells triggered significant K + current, indicating that a substantial amount of K + is secreted into the lumen during stimulation. Nevertheless, the K + content of the primary saliva is relatively low, suggesting that K + might be reabsorbed through the apical membrane. Therefore, we investigated the localization of Na + -K + pumps in acinar cells. We show that the pumps appear evenly distributed throughout the whole plasma membrane, including the apical pole of the cell. Based on these results, a new mathematical model of salivary fluid secretion is presented, where the pump reabsorbs K + from and secretes Na + to the lumen, which can partially supplement the paracellular Na + pathway.

Paradoxes of the influence of small Ni impurity additions in a NaCl crystal on the kinetics of its magnetoplasticity

NASA Astrophysics Data System (ADS)

Alshits, V. I.; Darinskaya, E. V.; Koldaeva, M. V.; Petrzhik, E. A.

2016-01-01

A comparative study of magnetoplasticity in two types of NaCl crystals differing in impurity content only by a small Ni addition (0.06 ppm) in one of them, NaCl(Ni), has been carried out. Two methods of sample magnetic exposure were used: in a constant field B = 0-0.6 T and in crossed fields in the EPR scheme—the Earth's field B Earth (50 μT) and a variable pumping field tilde B( ˜ 1 μ T) at frequencies ν 1 MHz. In the experiments in the EPR scheme, the change of the field orientation from tilde B bot B_{Earth} to . {tilde B} |B_{Earth} led to almost complete suppression of the effect in the NaCl(Ni) crystals and reduced only slightly (approximately by 20%) the height of the resonance peak of dislocation mean paths in the crystals without Ni, with the amplitude of the mean paths in NaCl(Ni) in the orientation tilde B bot B_{Earth} having been appreciably lower than that in NaCl. In contrast, upon exposure to a constant magnetic field, a more intense effect was observed in the crystal with Ni. The threshold pumping field amplitude tilde B, below which the effect is absent under resonance conditions, for the NaCl(Ni) crystals turned out to be a factor of 5 smaller than that for NaCl, while the thresholds of a constant magnetic field coincide for both types of crystals. All these differences are discussed in detail and interpreted.

Investigation into the role of NaCl deposited on oxide and metal substrates in the initiation of hot corrosion

NASA Technical Reports Server (NTRS)

Birks, N.

1981-01-01

Morphological aspects of the conversion to Na2SO4 of NaCl deposits over the temperature range 500-700 C, in air with added SO2 and H2O. Progress of the reaction was observed by withdrawing samples at various times and examining them under the scanning electron microscope using EDAX to assess the extent of chloride to sulfate conversion. These initial results show that the conversion to Na2SO4 proceeds directly on the sodium chloride surface as well as on the surrounding substrate due to evaporation of NaCl from the solid particle. The mechanism of this reaction could involve reaction in the vapor to produce Na2SO4 which then deposits, alternatively Na2SO4 could form directly on the substrate surface due to direct reaction there between the vapors NaCl, SO2 and O2.

H2O activity in concentrated NaCl solutions at high pressures and temperatures measured by the brucite-periclase equilibrium

NASA Astrophysics Data System (ADS)

Aranovich, L. Y.; Newton, R. C.

1996-10-01

H2O activities in concentrated NaCl solutions were measured in the ranges 600° 900° C and 2 15 kbar and at NaCl concentrations up to halite saturation by depression of the brucite (Mg(OH)2) periclase (MgO) dehydration equilibrium. Experiments were made in internally heated Ar pressure apparatus at 2 and 4.2 kbar and in 1.91-cm-diameter piston-cylinder apparatus with NaCl pressure medium at 4.2, 7, 10 and 15 kbar. Fluid compositions in equilibrium with brucite and periclase were reversed to closures of less than 2 mol% by measuring weight changes after drying of punctured Pt capsules. Brucite-periclase equilibrium in the binary system was redetermined using coarsely crystalline synthetic brucite and periclase to inhibit back-reaction in quenching. These data lead to a linear expression for the standard Gibbs free energy of the brucite dehydration reaction in the experimental temperature range: ΔG° (±120J)=73418 134.95 T(K). Using this function as a baseline, the experimental dehydration points in the system MgO-H2O-NaCl lead to a simple systematic relationship of high-temperature H2O activity in NaCl solution. At low pressure and low fluid densities near 2 kbar the H2O activity is closely approximated by its mole fraction. At pressures of 10 kbar and greater, with fluid densities approaching those of condensed H2O, the H2O activity becomes nearly equal to the square of its mole fraction. Isobaric halite saturation points terminating the univariant brucite-periclase curves were determined at each experimental pressure. The five temperature-composition points in the system NaCl-H2O are in close agreement with the halite saturation curves (liquidus curves) given by existing data from differential thermal analysis to 6 kbar. Solubility of MgO in the vapor phase near halite saturation is much less than one mole percent and could not have influenced our determinations. Activity concentration relations in the experimental P-T range may be retrieved for the binary

A Novel Mechanism of pH Buffering in C. elegans Glia: Bicarbonate Transport via the Voltage-Gated ClC Cl- Channel CLH-1.

PubMed

Grant, Jeff; Matthewman, Cristina; Bianchi, Laura

2015-12-16

An important function of glia is the maintenance of the ionic composition and pH of the synaptic microenvironment. In terms of pH regulation, HCO3 (-) buffering has been shown to be important in both glia and neurons. Here, we used in vivo fluorescent pH imaging and RNA sequencing of the amphid sheath glia of Caenorhabditis elegans to reveal a novel mechanism of cellular HCO3 (-) uptake. While the classical mechanism of HCO3 (-) uptake involves Na(+)/HCO3 (-) cotransporters, here we demonstrate that the C. elegans ClC Cl(-) channel CLH-1 is highly permeable to HCO3 (-) and mediates HCO3 (-) uptake into amphid sheath glia. CLH-1 has homology and electrophysiological properties similar to the mammalian ClC-2 Cl(-) channel. Our data suggest that, in addition to maintaining synaptic Cl(-) concentration, these channels may also be involved in maintenance of synaptic pH via HCO3 (-) flux. These findings provide an exciting new facet of study regarding how pH is regulated in the brain. Maintenance of pH is essential for the physiological function of the nervous system. HCO3 (-) is crucial for pH regulation and is transported into the cell via ion transporters, including ion channels, the molecular identity of which remains unclear. In this manuscript, we describe our discovery that the C. elegans amphid sheath glia regulate intracellular pH via HCO3 (-) flux through the voltage-gated ClC channel CLH-1. This represents a novel function for ClC channels, which has implications for their possible role in mammalian glial pH regulation. This discovery may also provide a novel therapeutic target for pathologic conditions, such as ischemic stroke where acidosis leads to widespread death of glia and subsequently neurons. Copyright © 2015 the authors 0270-6474/15/3516377-21$15.00/0.

Basolateral membrane Na/base cotransport is dependent on CO2/HCO3 in the proximal convoluted tubule

PubMed Central

1987-01-01

The mechanism of basolateral membrane base transport was examined in the in vitro microperfused rabbit proximal convoluted tubule (PCT) in the absence and presence of ambient CO2/HCO3- by means of the microfluorometric measurement of cell pH. The buffer capacity of the cells measured using rapid NH3 washout was 42.8 +/- 5.6 mmol.liter-1.pH unit-1 in the absence and 84.6 +/- 7.3 mmol.liter-1.pH unit-1 in the presence of CO2/HCO3-. In the presence of CO2/HCO3-, lowering peritubular pH from 7.4 to 6.8 acidified the cell by 0.30 pH units and lowering peritubular Na from 147 to 0 mM acidified the cell by 0.25 pH units. Both effects were inhibited by peritubular 4-acetamido-4'- isothiocyanostilbene-2,2'-disulfonate (SITS). In the absence of exogenous CO2/HCO3-, lowering peritubular pH from 7.4 to 6.8 acidified the cell by 0.25 pH units and lowering peritubular Na from 147 to 0 mM decreased cell pH by 0.20 pH units. Lowering bath pH from 7.4 to 6.8 induced a proton flux of 643 +/- 51 pmol.mm-1.min-1 in the presence of exogenous CO2/HCO3- and 223 +/- 27 pmol.mm-1.min-1 in its absence. Lowering bath Na from 147 to 0 mM induced proton fluxes of 596 +/- 77 pmol.mm-1.min-1 in its absence. The cell acidification induced by lowering bath pH or bath Na in the absence of CO2/HCO3- was inhibited by peritubular SITS or by acetazolamide, whereas peritubular amiloride had no effect. In the absence of exogenous CO2/HCO3-, cyanide blocked the cell acidification induced by bath Na removal, but was without effect in the presence of exogenous CO2/HCO3-. We reached the following conclusions. (a) The basolateral Na/base n greater than 1 cotransporter in the rabbit PCT has an absolute requirement for CO2/HCO3-. (b) In spite of this CO2 dependence, in the absence of exogenous CO2/HCO3-, metabolically produced CO2/HCO3- is sufficient to keep the transporter running at 30% of its control rate in the presence of ambient CO2/HCO3- . (c) There is no apparent amiloride-sensitive Na/H antiporter on

High-NaCl diet impairs dynamic renal blood flow autoregulation in rats with adenine-induced chronic renal failure.

PubMed

Saeed, Aso; DiBona, Gerald F; Grimberg, Elisabeth; Nguy, Lisa; Mikkelsen, Minne Line Nedergaard; Marcussen, Niels; Guron, Gregor

2014-03-15

This study examined the effects of 2 wk of high-NaCl diet on kidney function and dynamic renal blood flow autoregulation (RBFA) in rats with adenine-induced chronic renal failure (ACRF). Male Sprague-Dawley rats received either chow containing adenine or were pair-fed an identical diet without adenine (controls). After 10 wk, rats were randomized to either remain on the same diet (0.6% NaCl) or to be switched to high 4% NaCl chow. Two weeks after randomization, renal clearance experiments were performed under isoflurane anesthesia and dynamic RBFA, baroreflex sensitivity (BRS), systolic arterial pressure variability (SAPV), and heart rate variability were assessed by spectral analytical techniques. Rats with ACRF showed marked reductions in glomerular filtration rate and renal blood flow (RBF), whereas mean arterial pressure and SAPV were significantly elevated. In addition, spontaneous BRS was reduced by ∼50% in ACRF animals. High-NaCl diet significantly increased transfer function fractional gain values between arterial pressure and RBF in the frequency range of the myogenic response (0.06-0.09 Hz) only in ACRF animals (0.3 ± 4.0 vs. -4.4 ± 3.8 dB; P < 0.05). Similarly, a high-NaCl diet significantly increased SAPV in the low-frequency range only in ACRF animals. To conclude, a 2-wk period of a high-NaCl diet in ACRF rats significantly impaired dynamic RBFA in the frequency range of the myogenic response and increased SAPV in the low-frequency range. These abnormalities may increase the susceptibility to hypertensive end-organ injury and progressive renal failure by facilitating pressure transmission to the microvasculature.

Control of Glucose- and NaCl-Induced Biofilm Formation by rbf in Staphylococcus aureus

PubMed Central

Lim, Yong; Jana, Malabendu; Luong, Thanh T.; Lee, Chia Y.

2004-01-01

Both Staphylococcus aureus and S. epidermidis are capable of forming biofilm on biomaterials. We used Tn917 mutagenesis to identify a gene, rbf, affecting biofilm formation in S. aureus NCTC8325-4. Sequencing revealed that Rbf contained a consensus region signature of the AraC/XylS family of regulators, suggesting that Rbf is a transcriptional regulator. Insertional duplication inactivation of the rbf gene confirmed that the gene was involved in biofilm formation on polystyrene and glass. Phenotypic analysis of the wild type and the mutant suggested that the rbf gene mediates the biofilm formation of S. aureus at the multicellular aggregation stage rather than at initial attachment. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis demonstrated that the mutation resulted in the loss of an ∼190-kDa protein. Biofilm production by the mutant could be restored by complementation with a 2.5-kb DNA fragment containing the rbf gene. The rbf-specific mutation affected the induction of biofilm formation by glucose and a high concentration of NaCl but not by ethanol. The mutation did not affect the transcription of the ica genes previously shown to be required for biofilm formation. Taken together, our results suggest that the rbf gene is involved in the regulation of the multicellular aggregation step of S. aureus biofilm formation in response to glucose and salt and that this regulation may be mediated through the 190-kDa protein. PMID:14729698

Phenolic Compounds and Expression of 4CL Genes in Silver Birch Clones and Pt4CL1a Lines

PubMed Central

Sutela, Suvi; Hahl, Terhi; Tiimonen, Heidi; Aronen, Tuija; Ylioja, Tiina; Laakso, Tapio; Saranpää, Pekka; Chiang, Vincent; Julkunen-Tiitto, Riitta; Häggman, Hely

2014-01-01

A small multigene family encodes 4-coumarate:CoA ligases (4CLs) catalyzing the CoA ligation of hydroxycinnamic acids, a branch point step directing metabolites to a flavonoid or monolignol pathway. In the present study, we examined the effect of antisense Populus tremuloides 4CL (Pt4CL1) to the lignin and soluble phenolic compound composition of silver birch (Betula pendula) Pt4CL1a lines in comparison with non-transgenic silver birch clones. The endogenous expression of silver birch 4CL genes was recorded in the stems and leaves and also in leaves that were mechanically injured. In one of the transgenic Pt4CL1a lines, the ratio of syringyl (S) and guaiacyl (G) lignin units was increased. Moreover, the transcript levels of putative silver birch 4CL gene (Bp4CL1) were reduced and contents of cinnamic acid derivatives altered. In the other two Pt4CL1a lines changes were detected in the level of individual phenolic compounds. However, considerable variation was found in the transcript levels of silver birch 4CLs as well as in the concentration of phenolic compounds among the transgenic lines and non-transgenic clones. Wounding induced the expression of Bp4CL1 and Bp4CL2 in leaves in all clones and transgenic lines, whereas the transcript levels of Bp4CL3 and Bp4CL4 remained unchanged. Moreover, minor changes were detected in the concentrations of phenolic compounds caused by wounding. As an overall trend the wounding decreased the flavonoid content in silver birches and increased the content of soluble condensed tannins. The results indicate that by reducing the Bp4CL1 transcript levels lignin composition could be modified. However, the alterations found among the Pt4CL1a lines and the non-transgenic clones were within the natural variation of silver birches, as shown in the present study by the clonal differences in the transcripts levels of 4CL genes, soluble phenolic compounds and condensed tannins. PMID:25502441

Genetic polymorphisms in Na+-taurocholate co-transporting polypeptide (NTCP) and ileal apical sodium-dependent bile acid transporter (ASBT) and ethnic comparisons of functional variants of NTCP among Asian populations.

PubMed

Pan, Wei; Song, Im-Sook; Shin, Ho-Jung; Kim, Min-Hye; Choi, Yeong-Lim; Lim, Su-Jeong; Kim, Woo-Young; Lee, Sang-Seop; Shin, Jae-Gook

2011-06-01

Genetic variants of Na(+)-taurocholate co-transporting polypeptide (NTCP; SLC10A1) and ileal apical sodium-dependent bile acid transporter (ASBT; SLC10A2), which greatly contribute to bile acid homeostasis, were extensively explored in the Korean population and functional variants of NTCP were compared among Asian populations. From direct DNA sequencing, six SNPs were identified in the SLC10A1 gene and 14 SNPs in the SLC10A2 gene. Three of seven coding variants were non-synonymous SNPs: two variants from SLC10A1 (A64T, S267F) and one from SLC10A2 (A171S). No linkage was analysed in the SLC10A1 gene because of low frequencies of genetic variants, and the SLC10A2 gene was composed of two separated linkage disequilibrium blocks contrary to the white population. The stably transfected NTCP-A64T variant showed significantly decreased uptakes of taurocholate and rosuvastatin compared with wild-type NTCP. The decreased taurocholate uptake and increased rosuvastatin uptake were shown in the NTCP-S267F variant. The allele frequencies of these functional variants were 1.0% and 3.1%, respectively, in a Korean population. However, NTCP-A64T was not found in Chinese and Vietnamese subjects. The frequency distribution of NTCP-S267F in Koreans was significantly lower than those in Chinese and Vietnamese populations. Our data suggest that NTCP-A64T and -S267F variants cause substrate-dependent functional change in vitro, and show ethnic difference in their allelic frequencies among Asian populations although the clinical relevance of these variants is remained to be evaluated.

Effect of TPA on ion fluxes and DNA synthesis in vascular smooth muscle cells

PubMed Central

1985-01-01

Previous reports have suggested that phorbol esters can decrease the affinity of epidermal growth factor (EGF) for its cellular receptors. Investigations of the consequences of the interaction between phorbol esters and EGF, however, have been limited to EGF-stimulated Na/H exchange in A431 cells (Whitely, B., D. Cassel, Y.-X. Zuang, and L. Glaser, 1984, J. Cell Biol., 99:1162-1166). In the present study, the effect of the phorbol ester 12-O-tetradecanoyl phorbol-13-acetate (TPA) on EGF-stimulated ion transport and DNA synthesis was determined in cultured vascular smooth muscle cells (A7r5). It was found that TPA stimulated Na/H exchange when added alone (half-maximal stimulatory concentration, 25 nM). However, when cells were pretreated with TPA and then challenged with EGF, TPA significantly inhibited EGF-stimulated Na/H exchange (78%; half-maximal inhibition [Ki] at 2.5 nM). Subsequently the effects of TPA on Na/K/Cl co-transport were measured. TPA was observed to inhibit Na/K/Cl co-transport (half-maximal inhibitory concentration, 50 nM) and also to inhibit EGF-stimulated Na/K/Cl co-transport (100%; Ki at 5 nM). Finally, the effects of TPA on DNA synthesis were assessed. TPA had a modest stimulatory effect on DNA synthesis (half-maximal stimulatory concentration, 6 nM), but had a significant inhibitory effect on EGF-stimulated DNA synthesis (56%; Ki at 5 nM). These findings suggest that the inhibitory effect of TPA on EGF-receptor functions goes beyond previously reported effects on Na/H exchange in A431 cells and extends to EGF-stimulation of Na/K/Cl co- transport and DNA synthesis in vascular smooth muscle cells. PMID:2410432

AqSo_NaCl: Computer program to calculate p-T-V-x properties in the H2O-NaCl fluid system applied to fluid inclusion research and pore fluid calculation

NASA Astrophysics Data System (ADS)

Bakker, Ronald J.

2018-06-01

The program AqSo_NaCl has been developed to calculate pressure - molar volume - temperature - composition (p-V-T-x) properties, enthalpy, and heat capacity of the binary H2O-NaCl system. The algorithms are designed in BASIC within the Xojo programming environment, and can be operated as stand-alone project with Macintosh-, Windows-, and Unix-based operating systems. A series of ten self-instructive interfaces (modules) are developed to calculate fluid inclusion properties and pore fluid properties. The modules may be used to calculate properties of pure NaCl, the halite-liquidus, the halite-vapourus, dew-point and bubble-point curves (liquid-vapour), critical point, and SLV solid-liquid-vapour curves at temperatures above 0.1 °C (with halite) and below 0.1 °C (with ice or hydrohalite). Isochores of homogeneous fluids and unmixed fluids in a closed system can be calculated and exported to a.txt file. Isochores calculated for fluid inclusions can be corrected according to the volumetric properties of quartz. Microthermometric data, i.e. dissolution temperatures and homogenization temperatures, can be used to calculated bulk fluid properties of fluid inclusions. Alternatively, in the absence of total homogenization temperature the volume fraction of the liquid phase in fluid inclusions can be used to obtain bulk properties.

Composition of steam in the system NaCl-KCl-H2O-quartz at 600°C

USGS Publications Warehouse

Fournier, Robert O.; Thompson, J. Michael

1993-01-01

In the system NaCl-KCl-H2O, with and without ??-quartz present, steam was equilibrated in a large-volume reaction vessel with brine and/or precipitated salt at 600??C and pressures ranging from about 100 to 0.4 MPa. Episodically, steam was extracted for chemical analysis, accompanied by a decrease in pressure within the reaction vessel. In the absence of precipitated salt, within the analytical uncertainty stoichiometric quantities of Cl and total alkali, metals (Na + K) dissolve in steam coexisting with chloriderich brine. In contrast, in the presence of precipitated salt (in our experiments halite with some KCl in solid solution), significant excess chloride as associated hydrogen chloride (HCl0??) dissolves in steam. The HCl0 is generated by the reaction of steam with solid NaCl(s), producing solid NaOH(s) that diffuses into halite, forming a solid solution. In our quasistatic experiments, compared to dynamic flow-through experiments of others, higher initial ratios of H2O/NaCl have apparently resulted in higher model fractions of NaOH(s) in solid solution in halite. This, in turn, resulted in incrementally higher concentrations of associated NaOHo dissolved in steam. Addition of quartz to the system NaCl + KC1 + H2O resulted in an order of magnitude increase in the concentration of HCl0 dissolved in steam, apparently as a consequence of the formation of sodium disilicate by reaction of silica with NaOH(s). The measured dissolved silica in steam saturated with alkali halides at 600??C in the pressure range 7-70 MPa agrees nicely with calculated values of the solubility of ??-quartz obtained using the equation of Fournier and Potter (1982), corrected for dissolved salt by the method of fournier (1983). Na K ratios in steam at 600??C tend to be slightly greater than in coexisting brine. When precipitated halite is present, larger mole fractions of NaOH(s) in solid solution in that halite apparently result in even larger Na K ratios in coexisting steam

Four new chalcohalides, NaBa{sub 2}SnS{sub 4}Cl, KBa{sub 2}SnS{sub 4}Cl, KBa{sub 2}SnS{sub 4}Br and CsBa{sub 2}SnS{sub 4}Cl: Syntheses, crystal structures and optical properties

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Chao; Feng, Kai; Tu, Heng

Four new chalcohalides, namely NaBa{sub 2}SnS{sub 4}Cl, KBa{sub 2}SnS{sub 4}Cl, KBa{sub 2}SnS{sub 4}Br, and CsBa{sub 2}SnS{sub 4}Cl, have been synthesized by the conventional high temperature solid-state reactions. They crystallize in three different space groups: space group I4/mcm for NaBa{sub 2}SnS{sub 4}Cl and KBa{sub 2}SnS{sub 4}Cl, Pnma for KBa{sub 2}SnS{sub 4}Br, and P2{sub 1}/c for CsBa{sub 2}SnS{sub 4}Cl. In all four compounds, the X{sup −} halide anions are only connected to six alkali metal or Ba cations, and the Sn atoms are only tetrahedrally enjoined to four S atoms. However, the M–X–Ba pseudo layers and the SnS{sub 4} tetrahedra are arrangedmore » in different ways in the three structural types, which demonstrates the interesting effect of ionic radii on the crystal structures. UV–vis–NIR spectroscopy measurements indicate that NaBa{sub 2}SnS{sub 4}Cl, KBa{sub 2}SnS{sub 4}Cl, KBa{sub 2}SnS{sub 4}Br, and CsBa{sub 2}SnS{sub 4}Cl have band gaps of 2.28, 2.30, 1.95, and 2.06 eV, respectively. - Graphical abstract: A new series of chalcohalides, NaBa{sub 2}SnS{sub 4}Cl, KBa{sub 2}SnS{sub 4}Cl, KBa{sub 2}SnS{sub 4}Br and CsBa{sub 2}SnS{sub 4}Cl have been obtained. They present three different space groups: NaBa{sub 2}SnS{sub 4}Cl and KBa{sub 2}SnS{sub 4}Cl in space group I4/mcm, KBa{sub 2}SnS{sub 4}Br in Pnma and CsBa{sub 2}SnS{sub 4}Cl in space group P2{sub 1}/c. UV–vis–NIR spectroscopy measurements indicate that NaBa{sub 2}SnS{sub 4}Cl, KBa{sub 2}SnS{sub 4}Cl, KBa{sub 2}SnS{sub 4}Br and CsBa{sub 2}SnS{sub 4}Cl have band gaps of 2.28, 2.30 1.95, and 2.06 eV, respectively. - Highlights: • Four new chalcohalides, NaBa{sub 2}SnS{sub 4}Cl, KBa{sub 2}SnS{sub 4}Cl, KBa{sub 2}SnS{sub 4}Br and CsBa{sub 2}SnS{sub 4}Cl were obtained. • They adopt three different structures owing to different ionic radii and elemental electronegativity. • NaBa{sub 2}SnS{sub 4}Cl, KBa{sub 2}SnS{sub 4}Cl, KBa{sub 2}SnS{sub 4}Br and CsBa{sub 2}SnS{sub 4}Cl have

HMSN/ACC truncation mutations disrupt brain-type creatine kinase-dependant activation of K+/Cl- co-transporter 3.

PubMed

Salin-Cantegrel, Adèle; Shekarabi, Masoud; Holbert, Sébastien; Dion, Patrick; Rochefort, Daniel; Laganière, Janet; Dacal, Sandra; Hince, Pascale; Karemera, Liliane; Gaspar, Claudia; Lapointe, Jean-Yves; Rouleau, Guy A

2008-09-01

The potassium-chloride co-transporter 3 (KCC3) is mutated in hereditary motor and sensory neuropathy with agenesis of the corpus callosum (HMSN/ACC); however, the molecular mechanisms of HMSN/ACC pathogenesis and the exact role of KCC3 in the development of the nervous system remain poorly understood. The functional regulation of this transporter by protein partners is also largely unknown. Using a yeast two-hybrid approach, we discovered that the C-terminal domain (CTD) of KCC3, which is lost in most HMSN/ACC-causing mutations, directly interacts with brain-specific creatine kinase (CK-B), an ATP-generating enzyme that is also a partner of KCC2. The interaction of KCC3 with CK-B was further confirmed by in vitro glutathione S-transferase pull-down assay, followed by sequencing of the pulled-down complexes. In transfected cultured cells, immunofluorescence labeling showed that CK-B co-localizes with wild-type KCC3, whereas the kinase fails to interact with the inactive truncated KCC3. Finally, CK-B's inhibition by DNFB results in reduction of activity of KCC3 in functional assays using Xenopus laevis oocytes. This physical and functional association between the co-transporter and CK-B is, therefore, the first protein-protein interaction identified to be potentially involved in the pathophysiology of HMSN/ACC.

Intracellular pH Regulation in Cultured Astrocytes from Rat Hippocampus

PubMed Central

Bevensee, Mark O.; Apkon, Michael; Boron, Walter F.

1997-01-01

In the preceding paper (Bevensee, M.O., R.A. Weed, and W.F. Boron. 1997. J. Gen. Physiol. 110: 453–465.), we showed that a Na+-driven influx of HCO3 − causes the increase in intracellular pH (pHi) observed when astrocytes cultured from rat hippocampus are exposed to 5% CO2/17 mM HCO3 −. In the present study, we used the pH-sensitive fluorescent indicator 2′,7′-biscarboxyethyl-5,6-carboxyfluorescein (BCECF) and the perforated patch-clamp technique to determine whether this transporter is a Na+-driven Cl-HCO3 exchanger, an electrogenic Na/HCO3 cotransporter, or an electroneutral Na/HCO3 cotransporter. To determine if the transporter is a Na+-driven Cl-HCO3 exchanger, we depleted the cells of intracellular Cl− by incubating them in a Cl−-free solution for an average of ∼11 min. We verified the depletion with the Cl−-sensitive dye N-(6-methoxyquinolyl)acetoethyl ester (MQAE). In Cl−-depleted cells, the pHi still increases after one or more exposures to CO2/HCO3 −. Furthermore, the pHi decrease elicited by external Na+ removal does not require external Cl−. Therefore, the transporter cannot be a Na+-driven Cl-HCO3 exchanger. To determine if the transporter is an electrogenic Na/ HCO3 cotransporter, we measured pHi and plasma membrane voltage (Vm) while removing external Na+, in the presence/absence of CO2/HCO3 − and in the presence/absence of 400 μM 4,4′-diisothiocyanatostilbene-2,2′-disulphonic acid (DIDS). The CO2/HCO3 − solutions contained 20% CO2 and 68 mM HCO3 −, pH 7.3, to maximize the HCO3 − flux. In pHi experiments, removing external Na+ in the presence of CO2/HCO3 − elicited an equivalent HCO3 − efflux of 281 μM s−1. The HCO3 − influx elicited by returning external Na+ was inhibited 63% by DIDS, so that the predicted DIDS-sensitive Vm change was 3.3 mV. Indeed, we found that removing external Na+ elicited a DIDS-sensitive depolarization that was 2.6 mV larger in the presence than in the absence of CO2/ HCO3 �

Improvement of bioinsecticides production through adaptation of Bacillus thuringiensis cells to heat treatment and NaCl addition.

PubMed

Ghribi, D; Zouari, N; Jaoua, S

2005-01-01

The present work aimed to increase yields of delta-endotoxin production through adaptation of Bacillus thuringiensis cells to heat shock and sodium chloride and to investigate their involvements in bioinsecticides production improvement. Growing B. thuringiensis cells were heat treated after different incubation times to study the response of the adaptative surviving cells in terms of delta-endotoxin synthesis. Similarly, adaptation of B. thuringiensis cells to sodium chloride was investigated. Adaptation to combined stressors was also evaluated. When applied separately in the glucose-based medium, 20-min heat treatment of 6-h-old cultures and addition of 7 g l(-1) NaCl at the beginning of the incubation gave respectively 38 and 27% delta-endotoxin production improvements. Heat shock improved toxin synthesis yields, while NaCl addition improved delta-endotoxin production by increasing the spore titres without significant effect on toxin synthesis yields. Cumulative improvements (66%) were obtained by combination of the two stressors at the conditions previously established for each one. Interestingly, when the similar approach was conducted by using the large scale production medium based on gruel and fish meal, 17, 8 and 29% delta-endotoxin production improvements were respectively, obtained with heat shock, NaCl and combined stressors. Heat treatment of vegetative B. thuringiensis cells and NaCl addition to the culture media improved bioinsecticides production. Heat treatment increased toxin synthesis yields, while addition of NaCl increased biomass production yields. Cumulative improvements of 66 and 29% were obtained in glucose and economic production media, respectively. Overproduction of bioinsecticides by B. thuringiensis could be obtained by the combination of heat treatment of vegetative cells and addition of NaCl to the culture medium. This should contribute to a significant reduction of the cost of B. thuringiensis bioinsecticides production and

NaCl-assisted one-step growth of MoS2-WS2 in-plane heterostructures

NASA Astrophysics Data System (ADS)

Wang, Zhan; Xie, Yong; Wang, Haolin; Wu, Ruixue; Nan, Tang; Zhan, Yongjie; Sun, Jing; Jiang, Teng; Zhao, Ying; Lei, Yimin; Yang, Mei; Wang, Weidong; Zhu, Qing; Ma, Xiaohua; Hao, Yue

2017-08-01

Transition metal dichalcogenides (TMDs) have attracted considerable interest for exploration of next-generation electronics and optoelectronics in recent years. Fabrication of in-plane lateral heterostructures between TMDs has opened up excellent opportunities for engineering two-dimensional materials. The creation of high quality heterostructures with a facile method is highly desirable but it still remains challenging. In this work, we demonstrate a one-step growth method for the construction of high-quality MoS2-WS2 in-plane heterostructures. The synthesis was carried out using ambient pressure chemical vapor deposition (APCVD) with the assistance of sodium chloride (NaCl). It was found that the addition of NaCl played a key role in lowering the growth temperatures, in which the Na-containing precursors could be formed and condensed on the substrates to reduce the energy of the reaction. As a result, the growth regimes of MoS2 and WS2 are better matched, leading to the formation of in-plane heterostructures in a single step. The heterostructures were proved to be of high quality with a sharp and clear interface. This newly developed strategy with the assistance of NaCl is promising for synthesizing other TMDs and their heterostructures.

Potassium Supplementation Prevents Sodium Chloride Cotransporter Stimulation during Angiotensin II Hypertension

PubMed Central

Veiras, Luciana C.; Han, Jiyang; Ralph, Donna L.; McDonough, Alicia A.

2016-01-01

Ang II hypertension increases distal tubule Na-Cl cotransporter (NCC) abundance and phosphorylation (NCCp), as well as epithelial Na+ channel (ENaC) abundance and activating cleavage. Acutely raising plasma [K+] by infusion or ingestion provokes a rapid decrease in NCCp that drives a compensatory kaliuresis. The first aim tested whether acutely raising plasma [K+] with a single 3 hr 2% potassium meal would lower NCCp in Sprague Dawley rats after 14 days of AngII (400 ng/kg/min). The potassium-rich meal neither decreased NCCp nor increased K+ excretion. AngII infused rats exhibited lower plasma [K+] versus controls (3.6 ± 0.2 vs. 4.5 ± 0.1 mmol/L, p < 0.05) suggesting that Ang II mediated ENaC activation provokes K+ depletion. The second aim tested whether doubling dietary potassium intake from 1% (A1K) to 2% (A2K) would prevent K+ depletion during AngII infusion and, thus, prevent NCC accumulation. A2K fed rats exhibited normal plasma [K+] and 2-fold higher K+ excretion and plasma [aldosterone] versus A1K. In A1K rats, NCC, NCCpS71, and NCCpT53 abundance increased 1.5- to 3-fold versus controls (p< 0.05). The rise in NCC and NCCp abundance was prevented in the A2K rats, yet blood pressure did not significantly decrease. ENaC subunit abundance and cleavage increased 1.5- to 3-fold in both A1K and A2K; ROMK abundance was unaffected by Ang II or dietary K+. In summary, the accumulation and phosphorylation of NCC seen during chronic AngII infusion hypertension is likely secondary to potassium deficiency driven by ENaC stimulation. PMID:27600183

Densities of L-Glutamic Acid HCl Drug in Aqueous NaCl and KCl Solutions at Different Temperatures

NASA Astrophysics Data System (ADS)