Glutamate transport via the human excitatory amino acid transporters is coupled to the co-transport of three Na(+) ions, one H(+) and the counter-transport of one K(+) ion. Transport by an archaeal homologue of the human glutamate transporters, Glt(Ph), whose three dimensional structure is known is also coupled to three Na(+) ions but only two Na(+) ion binding sites have been observed in the c...

The large majority of proteins of alkaliphilic Bacillus pseudofirmus OF4 grown at pH 7.5 and 10.5, as studied by two-dimensional gel electrophoresis analyses, did not exhibit significant pH-dependent variation. A new surface layer protein (SlpA) was identified in these studies. Although the prominence of some apparent breakdown products of SlpA in gels from pH 10.5-grown cells led to discovery ...

We investigated the effects of different ischemia-mimetic factors on intracellular Ca2+ concentration ([Ca2+]i). Ventricular myocytes were isolated from adult Wistar rats, and [Ca2+]i was measured using fluorescent indicator fluo-4 AM by confocal microscopy. Intracellular pH was measured using c5-(and-6)-carboxy SNARF-1 AM, a dual emission pH-sensitive ionophore. Myocytes were exposed to hypoxi...

Alkalophilic bacilli maintain a cytoplasmic pH that is lower than optimal external pH values. The current study, using isolated membrane vesicles from Bacillus alcalophilus, indicates that respiration results in proton extrusion as in other organisms. Cation/proton antiporters then catalyze inward proton movements. Upon energization with ascorbate/N,N,N',N'-tetramethyl-p-phenylenediamine, Na'-l...

The benzophenone dianion [diphenyloxidomethanide, (Ph(2)CO)(2-)], which occurs in the well known deeply violet sodium/benzophenone tetrahydrofuran solutions, was crystallised with sodium cations in form of the two polymeric chain compounds [Na(2)(Ph(2)CO)(tetraglyme)](infinity) and [Na(2)(Ph(2)CO)(thf)(2)](infinity). It was found to aggregate with its conjugated acid, the alcoholate (Ph(2)CHO)(...

The effect of phosphorylated phloretins on Na(+)-dependent phosphate uptake into rabbit renal brush-border membrane vesicles (BBMV) was examined. Na(+)-dependent phosphate uptake into isolated rabbit cortex BBMV was sensitive to 2'-phosphophloretin (2'-PP) and 2'-phospho-4',4,6'-trimethoxy phloretin (PTMP) in a dose-dependent and pH-dependent manner. PTMP inhibition of Na(+)-dependent phosphate...

We report here that intracellular pH (pH(i)) in cleavage-stage human embryos (2-8-cell) is regulated by at least two mechanisms: the HCO(3)(-)/Cl(-) exchanger (relieves alkalosis) and the Na(+)/H(+) antiporter (relieves acidosis). The mean pH(i) of cleavage-stage embryos was 7.12 +/- 0.008 (n = 199) with little variation between different stages. Embryos demonstrated robust recovery from alkalo...

Cation exchange capacity (CEC) is an important characteristic of zeolites, especially when they are used as adsorbents in the aqueous system. However, no international standard method exists for the determination of CEC of zeolites. We determined CEC of Linde-type A and Na-P1 type zeolites at various pH (4 to 10) with a simple method, where Na+-saturated zeolites were prepared, and then various...

To test the hypothesis that internal ion imbalances at high pH are caused by altered branchial ion transporting capacity and permeability, radiotracers (Na and Cl) were used to measure ion movements across the gills of intact rainbow trout (Oncorhynchus mykiss) during 3 d exposure to pH 9.5. At control pH (pH 8.0), the trout were in net ion balance, but by 8 h at high pH, 60%–70% reductions in ...

mRNA for two Na(+)-H(+)-exchanger isoforms 1 and 3 (NHE-1 and NHE-3) was detected by RT-PCR in fungiform and circumvallate taste receptor cells (TRCs). Anti-NHE-1 antibody binding was localized to the basolateral membranes, and the anti-NHE-3 antibody was localized in the apical membranes of fungiform and circumvallate TRCs. In a subset of TRCs, NHE-3 immunoreactivity was also detected in the i...