Activity of the multidrug transporter results in alkalinization of the cytosol: measurement of cytosolic pH by microinjection of a pH-sensitive dye.
AuthorsThiebaut F, Currier SJ, Whitaker J, Haugland RP, Gottesman MM, Pastan I, Willingham MC
JournalJ Histochem Cytochem
PubMed ID1692055
'Multidrug-resistant cells contain a plasma membrane efflux pump, the multidrug transporter, which actively expels certain hydrophobic drugs from the cytosol to the cell exterior. These drugs are usually positively charged at physiological pH. Because one might predict that this efflux of positively charged molecules might deplete the cytosol of protons, ... More
A novel role for carbonic anhydrase: cytoplasmic pH gradient dissipation in mouse small intestinal enterocytes.
AuthorsStewart AK, Boyd CA, Vaughan-Jones RD
JournalJ Physiol
PubMed ID10066935
'1. The spatial and temporal distribution of intracellular H+ ions in response to activation of a proton-coupled dipeptide transporter localized at the apical pole of mouse small intestinal isolated enterocytes was investigated using intracellular carboxy-SNARF-1 fluorescence in combination with whole-cell microspectrofluorimetry or confocal microscopy. 2. In Hepes-buffered Tyrode solution, application ... More
Nuclear pH gradient in mammalian cells revealed by laser microspectrofluorimetry.
AuthorsSeksek O, Bolard J
JournalJ Cell Sci
PubMed ID8834810
Intracellular pH has been measured by laser microspectrofluorimetry, using the pH-sensitive dyes SNARF-1, SNARF-calcein and SNARF-1-dextran. By this technique it was possible to accurately determine pH in volumes as small as 0.5 x 0.5 x 1 microns 3. The probes were loaded into the cells either by diffusion of their ... More
Local extracellular acidification caused by Ca(2+)-dependent exocytosis in PC12 cells.
AuthorsShuba YM, Dietrich CJ, Oermann E, Cleemann L, Morad M,
JournalCell Calcium
PubMed ID18346783
Exocytosis of acidic synaptic vesicles may produce local extracellular acidification, but this effect has not been measured directly and its magnitude may depend on the geometry and pH-buffering capacity of both the vesicles and the extracellular space. Here we have used SNARF dye immobilized by conjugation to dextran to measure ... More
Regional electroporation of single cardiac myocytes in a focused electric field.
AuthorsKlauke N, Smith G, Cooper JM,
JournalAnal Chem
PubMed ID20020746
There is now a significant interest in being able to locate single cells within geometrically defined regions of a microfluidic chip and to gain intracellular access through the local electroporation of the cell membrane. This paper describes the microfabrication of electroporation devices which can enable the regional electroporation of adult ... More
Tamoxifen inhibits acidification in cells independent of the estrogen receptor.
AuthorsAltan N, Chen Y, Schindler M, Simon SM
JournalProc Natl Acad Sci U S A
PubMed ID10200279
Tamoxifen has been reported to have numerous physiological effects that are independent of the estrogen receptor, including sensitization of resistant tumor cells to many chemotherapeutic agents. Drug-resistant cells sequester weak base chemotherapeutics in acidic organelles away from their sites of action in the cytosol and nucleus. This work reports that ... More
Defective acidification in human breast tumor cells and implications for chemotherapy.
AuthorsAltan N, Chen Y, Schindler M, Simon SM
JournalJ Exp Med
PubMed ID9584137
Multidrug resistance (MDR) is a significant problem in the treatment of cancer. Chemotherapeutic drugs distribute through the cyto- and nucleoplasm of drug-sensitive cells but are excluded from the nucleus in drug-resistant cells, concentrating in cytoplasmic organelles. Weak base chemotherapeutic drugs (e.g., anthracyclines and vinca alkaloids) should concentrate in acidic organelles. ... More
Intramolecular interactions mediate pH regulation of connexin43 channels.
AuthorsMorley GE, Taffet SM, Delmar M
JournalBiophys J
PubMed ID8785285
We have previously proposed that acidification-induced regulation of the cardiac gap junction protein connexin43 (Cx43) may be modeled as a particle-receptor interaction between two separate domains of Cx43: the carboxyl terminal (acting as a particle), and a region including histidine 95 (acting as a receptor). Accordingly, intracellular acidification would lead ... More
Determination of pH by microfluorometry: intracellular and interstitial pH regulation in developing early-stage fish embryos (Danio rerio).
AuthorsMölich A, Heisler N
JournalJ Exp Biol
PubMed ID16244172
Microfluorometric techniques were applied in vivo for continuous monitoring of specific acid-base parameters in zebrafish (Danio rerio) embryos during early stages of ontogeny. Dextran-coupled pH-sensitive single-excitation/dual-emission dye SNARF-1 was pressure-injected into individual cells or the interstitial space of 16- to 256-cell embryos, and pH was continuously recorded during subsequent development ... More
T-cells produce acidic niches in lymph nodes to suppress their own effector functions.
Authors
JournalNat Commun
PubMed ID32807791
Remote in vivo stress assessment of aquatic animals with microencapsulated biomarkers for environmental monitoring.
Authors
JournalSci Rep
PubMed ID27808253
Encapsulated enzymes with integrated fluorescence-control of enzymatic activity.
Authors
JournalJ Mater Chem B
PubMed ID32262409
Discovery of a picomolar potency pharmacological corrector of the mutant CFTR chloride channel.
Authors
JournalSci Adv
PubMed ID32128418
Distribution of PEG-coated hollow polyelectrolyte microcapsules after introduction into the circulatory system and muscles of zebrafish.
Authors
JournalBiol Open
PubMed ID29305467
Mouse pancreatic ductal organoid culture as a relevant model to study exocrine pancreatic ion secretion.