An experimental setup to study the pH dependence of standard ion-transfer potentials at the water/NPOE interface is presented. The system is composed of a microhole generated by laser photoablation in a 12-microm polyethylene terephthalate film, the aqueous phase consisting of a commercial immobilized pH gradient gel reswelled in electrolyte solution and a droplet of organic solution. Two elect...

librated with 0.02 AI KPO4, pH 8.0, containing 0.01 M 2-mercaptoethanol. Linear gradients were applied and the purifications obtained are expressed relative to the supernatant fluid of the sonic extract; all solutions contained 0.01 Al 2-mereaptoethanol. Glucosylating enzyme: gradient of 0.08 to 0.32 M NaCl in 0.02 M KPO4, pH 8.0-30X purification; dCTPase: gradient of 0.08 M to 0.32 Ml NaCl in ...

The mechanism and energetics of citrate transport in Leuconostoc oenos were investigated. Resting cells of L. oenos generate both a membrane potential (delta psi) and a pH gradient (delta pH) upon addition of citrate. After a lag time, the internal alkalinization is followed by a continuous alkalinization of the external medium, demonstrating the involvement of proton-consuming reactions in the...

II. ENTEROCYTE ENTRY In brush-border membrane vesicles (BBMV) from rat small intestine the time course of T transport is not influenced by the presence or the absence of Nat(or Kt) in the incubation medium [1].At concentrations <1.25 ƒÊM, T is taken up mainly by a saturable mechanism (Km, 0.8, 0; Jmax, 0.35 pmol. mg-1 protein. 4 s-1), while at higher concentrations a passive diffusion prevails ...

Studies of Na+ and H+ transport by confluent monolayers of the epithelial cell line LLC-PK1 were performed to verify the presence of a Na+/H+ exchange system. The presence of an outwardly directed H+ gradient produced a large stimulation of Na+ influx measured under net flux conditions. Amiloride (10(-3) M) completely inhibited Na+ influx stimulated by the H+ gradient and part of the Na+ influx...

Although limited data exist, electrode-measured pH values of human tumors and adjacent normal tissues, which are concurrently obtained by the same investigator in the same patient, consistently show that the electrode pH (believed to primarily represent tissue extracellular pH) is substantially and consistently lower in the tumor than in normal tissue. In contrast, the 31P-magnetic resonance sp...

17 Desloire, S. et al. (2003) Identification of the fertility restoration locus, Rfo, in radish, as a member of the pentatricopeptide-repeat protein family. EMBO Rep. 4, 588–594 18 Koizuka, N. et al. (2003) Genetic characterization of a pentatricopeptide repeat protein gene, orf687, that restores fertility in the cytoplasmic male-sterile Kosena radish. Plant J. 34, 407–415 19 Kazama, T. and Tor...

We have previously demonstrated (M. Stubbs, Z. M. Bhujwalla, G. M. Tozer, L. M. Rodrigues, R. J. Maxwell, R. Morgan, F. A. Howe, and J. R. Griffiths, NMR Biomed., 5: 351, 1992) that the intracellular pH (pHi) of several rat tumors is higher (> pH 7.0) than that of the tumor extracellular fluid (pHe), in contrast to normal tissues (e.g., liver) in which pHi is lower than pHe. In this paper we co...

In the presence of PP, as an energy source, the tonoplast-bound inorganic pyrophosphatase from Catharanthus roseus cells is able to create a proton-gradient which can drive the synthesis of ATP from ADP and Pi. ATP synthesis is linked to the pH-gradient dissipation as monitored by the recovery of the fluorescence intensity of quinacrine and by the amount of synthesized ATP measured by the biolu...