Abstract:
:We studied intracellular pH (pHi) regulation in the absence of HCO3- in single mesangial cells (MCs) with the pH-sensitive dye 2',7'-bis(2-carboxyethyl)-5(and -6)carboxyfluorescein. Our approach was to acid load the cells by an NH+4 prepulse and to monitor the subsequent pHi recovery. Previous work on MCs and other cells has shown that the recovery is prevented by adding ethylisopropyl amiloride (EIPA) or removing Na+ before the recovery begins, suggesting that at low pHi only Na-H exchange contributes to the recovery. This conclusion is often extrapolated to the entire pHi range. To test this, we interrupted the recovery with EIPA at various pHi values, finding that EIPA unmasked a background acidification that was negligible at pHi less than approximately 6.7 but increased steeply at higher pHi values. Correcting the total recovery rate for this EIPA-insensitive component, we found that the EIPA-sensitive (Na-H exchange) rate fell steeply with increasing pHi between 6.3 and 6.7 but was relatively pHi insensitive between 6.7 and 7.2. Thus, the recovery halts as pHi approaches approximately 7.2 not so much because Na-H exchange slows, but because acid loading accelerates. Applying the mitogen arginine vasopressin (AVP; 100 nM) caused a rapid pHi decrease of approximately 0.4, followed by a slower increase to a level approximately 0.15 higher than the initial pHi. Coincident with this biphasic change in pHi was a biphasic change in Na-H exchange kinetics. In the early phase (i.e., pHi recovery commencing approximately 8 min after AVP addition), AVP linearized the pHi dependence of the exchanger; its rate was unaffected by AVP at pHi less than approximately 6.7 but was progressively inhibited at higher pHi values. In the later phase (i.e., pHi recovery commencing approximately 14 min after AVP addition), AVP shifted this linear pHi dependence in the alkaline direction; the exchanger was stimulated at pHi less than 6.9 but was modestly inhibited at higher pHi values (i.e., in the physiological range). At all times, AVP greatly inhibited background acid loading. Thus, AVP raises steady-state pHi not because Na-H exchange is stimulated but because, although the exchanger is inhibited, acid loading is inhibited even more.
journal_name
Proc Natl Acad Sci U S Aauthors
Boyarsky G,Ganz MB,Cragoe EJ Jr,Boron WFdoi
10.1073/pnas.87.15.5921subject
Has Abstractpub_date
1990-08-01 00:00:00pages
5921-4issue
15eissn
0027-8424issn
1091-6490journal_volume
87pub_type
杂志文章abstract::For the polypentapeptide of elastin, (L-Val-L-Pro-Gly-L-Val-Gly)n, and appropriate analogs when suitably cross-linked, it has been previously demonstrated that development of elastomeric force at fixed length and length changes at fixed load occur as the result of an inverse temperature transition, with the temperatur...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.85.10.3407
更新日期:1988-05-01 00:00:00
abstract::In rodent models of Parkinson disease in which transplants of dissociated rodent and human embryonic mesencephalic tissue, rich in dopamine neurons, have been studied, only 5-20% of the dopamine neurons survive the implantation procedure. We have investigated the effects of inhibiting free radical generation with two ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.91.26.12408
更新日期:1994-12-20 00:00:00
abstract::We have examined the role of cyclooxygenase 2 (COX-2) in a model of inflammation in vivo. Carrageenan administration to the subcutaneous rat air pouch induces a rapid inflammatory response characterized by high levels of prostaglandins (PGs) and leukotrienes in the fluid exudate. The time course of the induction of CO...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.91.8.3228
更新日期:1994-04-12 00:00:00
abstract::Orchids employing sexual deceit attract males of their pollinator species through specific volatile signals that mimic female-released sex pheromones. One of these signals proved to be 2-ethyl-5-propylcyclohexan-1,3-dione (chiloglottone1), a new natural product that was shown to be most important in the relations betw...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.0900646106
更新日期:2009-06-02 00:00:00
abstract::The present paper summarizes future needs in information and tools, technology, infrastructure, training, funding, and bioinformatics, to provide the genomic knowledge and tools for breeding and biotechnological goals in maize. The National Corn Genome Initiative (NCGA) has developed through actions taken by the Natio...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.95.5.2029
更新日期:1998-03-03 00:00:00
abstract::Nonnative species richness typically declines along environmental gradients such as elevation. It is usually assumed that this is because few invaders possess the necessary adaptations to succeed under extreme environmental conditions. Here, we show that nonnative plants reaching high elevations around the world are n...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1013136108
更新日期:2011-01-11 00:00:00
abstract::Topological state of matter and lithium batteries are currently two hot topics in science and technology. Here we combine these two by exploring the possibility of using all-carbon-based porous topological semimetal for lithium battery anode material. Based on density-functional theory and the cluster-expansion method...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1618051114
更新日期:2017-01-24 00:00:00
abstract::We describe a synthetic ligand, "DAKLI" (Dynorphin A-analogue Kappa LIgand), related to the opioid peptide dynorphin A. A single reactive amino group at the extended carboxyl terminus permits various reporter groups to be attached, such as 125I-labeled Bolton-Hunter reagent, fluorescein isothiocyanate, or biotin. Thes...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.85.19.7375
更新日期:1988-10-01 00:00:00
abstract::The nuclear receptors LXRalpha and LXRbeta have been implicated in the control of cholesterol and fatty acid metabolism in multiple cell types. Activation of these receptors stimulates cholesterol efflux in macrophages, promotes bile acid synthesis in liver, and inhibits intestinal cholesterol absorption, actions that...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.112059299
更新日期:2002-05-28 00:00:00
abstract::Two photochromic activators of the electrogenic membrane of the electroplax of Electrophorus electricus are described. Trans-3,3'-bis[alpha-(trimethylammonium)methyl]azobenzene dibromide (Bis-Q), one of the most potent ever reported, is active at concentrations of less than 10(-7) M. Its cis isomer, which is obtained ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.68.8.1820
更新日期:1971-08-01 00:00:00
abstract::Phosphoinositides are essential lipid regulators of trafficking and signaling pathways of all eukaryotic cells. Phosphatidylinositol 4-phosphate (PtdIns4P) is an intermediate in the synthesis of several important phosphoinositide species but also serves as a regulatory molecule in its own right. Phosphatidylinositol 4...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1000157107
更新日期:2010-05-04 00:00:00
abstract::We outline a theory to quantify the interplay of entropic and selective forces on nucleotide organization and apply it to the genomes of single-stranded RNA viruses. We quantify these forces as intensive variables that can easily be compared between sequences, outline a computationally efficient transfer-matrix method...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1402285111
更新日期:2014-04-01 00:00:00
abstract::Alternative splicing is critical for diversifying eukaryotic proteomes, but the rules governing and coordinating splicing events among multiple alternate splice sites within individual genes are not well understood. We developed a quantitative PCR-based strategy to quantify the expression of the 12 transcripts encoded...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1116712108
更新日期:2011-12-20 00:00:00
abstract::Pyrimethamine (Pyr) targets dihydrofolate reductase of Plasmodium vivax (PvDHFR) as well as other malarial parasites, but its use as antimalarial is hampered by the widespread high resistance. Comparison of the crystal structures of PvDHFR from wild-type and the Pyr-resistant (SP21, Ser-58 --> Arg + Ser-117 --> Asn) s...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.0501747102
更新日期:2005-09-13 00:00:00
abstract::Immune-mediated pulmonary diseases are a significant public health concern. Analysis of leukocyte behavior in the lung is essential for understanding cellular mechanisms that contribute to normal and diseased states. Here, we used two-photon imaging to study neutrophil extravasation from pulmonary vessels and subseque...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1008737107
更新日期:2010-10-19 00:00:00
abstract::Madagascar periwinkle (Catharanthus roseus) is the sole source of the anticancer drugs vinblastine and vincristine, bisindole alkaloids derived from the dimerization of the terpenoid indole alkaloids vindoline and catharanthine. Full elucidation of the biosynthetic pathways of these compounds is a prerequisite for met...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1009003107
更新日期:2010-11-02 00:00:00
abstract::The venoms from three spider species, Araneus gemma, Neoscona arabesca, and Argiope aurantia, were shown to inhibit the high-affinity, sodium-independent L-glutamate-binding sites in rat brain synaptic membranes. The same three venoms caused concentration-dependent inhibition of the activity of the glutamate-binding g...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.81.17.5571
更新日期:1984-09-01 00:00:00
abstract::The MAL6 locus is one of five closely related unlinked loci, any one of which is sufficient for fermentation of maltose in Saccharomyces. Previous genetic analysis indicated that this locus is defined by two complementation groups, MALp and MALg. MALp reportedly is a regulatory gene required for inducible synthesis of...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.81.9.2811
更新日期:1984-05-01 00:00:00
abstract::In epithelial cells, sorting of membrane proteins to the basolateral surface depends on the presence of a basolateral sorting signal (BaSS) in their cytoplasmic domain. Amyloid precursor protein (APP), a basolateral protein implicated in the pathogenesis of Alzheimer's disease, contains a tyrosine-based BaSS, and muta...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.95.25.14745
更新日期:1998-12-08 00:00:00
abstract::Genes carried by EcoRI endonuclease-generated fragments of Staphylococcus plasmid DNA have been covalently joined to the E. coli antibiotic-resistance plasmid pSC101, and the resulting hybrid molecules have been introduced into E. coli by transformation. The newly constructed plasmids replicate as biologically functio...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.71.4.1030
更新日期:1974-04-01 00:00:00
abstract::NAD+ glycohydrolase activity is found at high levels in submitochondrial particles. It leads to the reaction products ADP-ribose, nicotinamide, and small amounts of 5'-AMP. Furthermore, submitochondrial particles catalyze the exchange reaction: [adenosine-14C]ADP-ribose + NAD+ in equilibrium [adenosine-14C]-NAD+ + ADP...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.80.11.3188
更新日期:1983-06-01 00:00:00
abstract::We have investigated the theory that the insulin-induced loss of insulin binding from adipocytes is due to internalization of insulin receptors. Cell-surface receptors were assessed by the binding capacity of intact cells at 16 degrees C. Total (i.e., cell-surface plus intracellular) receptors were assessed by solubil...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.79.2.427
更新日期:1982-01-01 00:00:00
abstract::Multiple paleoclimate proxies are required for robust assessment of past hydroclimatic conditions. Currently, estimates of drought variability over the past several thousand years are based largely on tree-ring records. We produced a 1,500-y record of winter precipitation in the Pacific Northwest using a physical mode...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 历史文章,杂志文章
doi:10.1073/pnas.1201083109
更新日期:2012-07-17 00:00:00
abstract::Bufonid anurans of the genus Atelopus contain both steroidal bufadienolides and various guanidinium alkaloids of the tetrodotoxin class. The former inhibit sodium-potassium ATPases, whereas the latter block voltage-dependent sodium channels. The structure of one guanidinium alkaloid, zetekitoxin AB, has remained a mys...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.0400368101
更新日期:2004-03-30 00:00:00
abstract::A sensitive assay for detection of eukaryotic RNA polymerase II has been developed. This assay depends on the ability of polymerase II to elongate a small RNA primer, oligo(U), hybridized to a single-stranded homopolymeric DNA template, poly(dA). The poly(dA).oligo(U)-dependent RNA polymerase II from calf thymus has b...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.82.23.7979
更新日期:1985-12-01 00:00:00
abstract::We investigated the structural and functional alterations of active lamellae during initial cell-cell collision and establishment of cell-cell contacts in wounded cultures of nontransformed rat epitheliocytes (IAR-2 line) and their ras-transformed descendants (C4 line). Typically, the leading edges of nontransformed c...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.94.3.879
更新日期:1997-02-04 00:00:00
abstract::Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system postulated to be a cell-mediated autoimmune disease in which interferon gamma (IFN-gamma) plays an important role. There is increased IFN-gamma secretion in MS, and IFN-gamma administration induces exacerbations of disease. We foun...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.94.2.599
更新日期:1997-01-21 00:00:00
abstract::Many cell surface receptors are multimeric proteins, composed of several structural domains, some involved in ligand recognition, whereas others are responsible for signal transduction. In most cases, the mechanism of how ligand interaction in the extracellular domains leads to the activation of effector domains remai...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1107775108
更新日期:2011-09-13 00:00:00
abstract::We investigated patterns of genetic diversity of Plasmodium falciparum associated with its two main African vectors: Anopheles gambiae and Anopheles funestus. We dissected 10,296 wild-caught mosquitoes from three tropical sites, two in Cameroon (Simbock and Tibati, separated by 320 km) and one in Kenya (Rota, >2,000 k...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.0702715104
更新日期:2007-05-08 00:00:00
abstract::We have studied the in vivo signaling mechanisms involved in nociceptin/orphanin FQ (Noci)-induced pain responses by using a flexor-reflex paradigm. Noci was 10,000 times more potent than substance P (SP) in eliciting flexor responses after intraplantar injection into the hind limb of mice, but the action of Noci seem...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.95.18.10949
更新日期:1998-09-01 00:00:00