Measurement of individual intracellular pH and membrane potential values in living cells

1999 ◽  
Author(s):  
Jan Slavik ◽  
Edvard Lanz ◽  
Petr Cimprich
Keyword(s):  
Membrane Potential ◽  
Intracellular Ph ◽  
Living Cells

scholarly journals On the Wireless Microwave Sensing of Bacterial Membrane Potential in Microfluidic-Actuated Platforms

Sensors ◽  
2021 ◽  
Vol 21 (10) ◽  
pp. 3420
Author(s):  
Marc Jofre ◽  
Lluís Jofre ◽  
Luis Jofre-Roca
Keyword(s):  
Membrane Potential ◽  
Living Cells ◽  
Membrane Potentials ◽  
Electromagnetic Properties ◽  
Bacterial Membrane ◽  
Microfluidic Platforms ◽  
Bacterial Membranes ◽  
Wireless Monitoring ◽  
Bacterial Dynamics ◽  
Engineered Systems

The investigation of the electromagnetic properties of biological particles in microfluidic platforms may enable microwave wireless monitoring and interaction with the functional activity of microorganisms. Of high relevance are the action and membrane potentials as they are some of the most important parameters of living cells. In particular, the complex mechanisms of a cell’s action potential are comparable to the dynamics of bacterial membranes, and consequently focusing on the latter provides a simplified framework for advancing the current techniques and knowledge of general bacterial dynamics. In this work, we provide a theoretical analysis and experimental results on the microwave detection of microorganisms within a microfluidic-based platform for sensing the membrane potential of bacteria. The results further advance the state of microwave bacteria sensing and microfluidic control and their implications for measuring and interacting with cells and their membrane potentials, which is of great importance for developing new biotechnologically engineered systems and solutions.

scholarly journals Cytoplasmic [Ca2+] and intracellular pH in lymphocytes. Role of membrane potential and volume-activated Na+/H+ exchange.

1987 ◽  
Vol 89 (2) ◽  
pp. 185-213 ◽  
Author(s):  
S Grinstein ◽  
S Cohen
Keyword(s):  
Protein Kinase C ◽  
Membrane Potential ◽  
Protein Kinase ◽  
Intracellular Ph ◽  
Enzyme Treatment ◽  
Membrane Hyperpolarization ◽  
Kinase C ◽  
Free Media ◽  
Stimulation Of

The effect of elevating cytoplasmic Ca2+ [( Ca2+]i) on the intracellular pH (pHi) of thymic lymphocytes was investigated. In Na+-containing media, treatment of the cells with ionomycin, a divalent cation ionophore, induced a moderate cytoplasmic alkalinization. In the presence of amiloride or in Na+-free media, an acidification was observed. This acidification is at least partly due to H+ (equivalent) uptake in response to membrane hyperpolarization since: it was enhanced by pretreatment with conductive protonophores, it could be mimicked by valinomycin, and it was decreased by depolarization with K+ or gramicidin. In addition, activation of metabolic H+ production also contributes to the acidification. The alkalinization is due to Na+/H+ exchange inasmuch as it is Na+ dependent, amiloride sensitive, and accompanied by H+ efflux and net Na+ gain. A shift in the pHi dependence underlies the activation of the antiport. The effect of [Ca2+]i on Na+/H+ exchange was not associated with redistribution of protein kinase C and was also observed in cells previously depleted of this enzyme. Treatment with ionomycin induced significant cell shrinking. Prevention of shrinking largely eliminated the activation of the antiport. Moreover, a comparable shrinking produced by hypertonic media also activated the antiport. It is concluded that stimulation of Na+/H+ exchange by elevation of [Ca2+]i is due, at least in part, to cell shrinking and does not require stimulation of protein kinase C.

scholarly journals A photocross-linking fluorescent indicator of mitochondrial membrane potential.

1993 ◽  
Vol 41 (4) ◽  
pp. 631-634 ◽  
Author(s):  
K M Hahn ◽  
P A Conrad ◽  
J C Chao ◽  
D L Taylor ◽  
A S Waggoner
Keyword(s):  
Membrane Potential ◽  
Electrical Potential ◽  
Living Cells ◽  
Covalent Attachment ◽  
Cross Linking ◽  
Mitochondrial Potential ◽  
Specific Staining ◽  
Fluorescent Indicators ◽  
3T3 Fibroblasts ◽  
Mitochondrial Staining

Ionic dyes that distribute across membranes according to electrical potential have proven valuable as fluorescent indicators of mitochondrial energetics in living cells. Applications have been limited, however, as potential-dependent staining is lost during cell fixation. We have produced a membrane potential indicator whose potential-dependent distribution can be made permanent, to enable correlation of membrane potential with cytochemical information from immunofluorescence. A carbocyanine dye was derivatized with a photoreactive nitrophenylazide moiety so that irradiation would induce nonspecific, covalent attachment to nearby molecules. Photo-induced cross-linking was observed in paper chromatography, when irradiation caused immobilization of the dye. The new dye, named PhoCy (photofixable cyanine), showed specific staining of mitochondria in living Swiss 3T3 fibroblasts. When living cells were stained, irradiated, and fixed with formaldehyde, mitochondrial staining was retained owing to cross-linking with mitochondrial components. Omission of irradiation eliminated mitochondrial staining in fixed cells. Labeling, irradiation, and fixation procedures were optimized to produce bright specific staining with minimal background. The indicator's sensitivity to mitochondrial potential was demonstrated by treating cells with 2,4-dinitrophenol, an uncoupler of mitochondrial electron transport, which decreased mitochondrial staining in living cells and in the corresponding fixed specimens.

Design and validation of a new ratiometric intracellular pH imaging probe using lanthanide-doped upconverting nanoparticles

2017 ◽  
Vol 46 (40) ◽  
pp. 13957-13965 ◽  
Author(s):  
Shuoren Du ◽  
Javier Hernández-Gil ◽  
Hao Dong ◽  
Xiaoyu Zheng ◽  
Guangming Lyu ◽  
...  
Keyword(s):  
Intracellular Ph ◽  
Quantitative Imaging ◽  
Living Cells ◽  
Ph Sensitive ◽  
Upconversion Nanoparticles ◽  
Imaging Probe ◽  
Ph Imaging ◽  
Ratiometric Probe ◽  
Subcellular Level

A ratiometric probe based on upconversion nanoparticles modified with a pH sensitive moiety for the quantitative imaging of pH at the subcellular level in living cells.

Ammonia movement and distribution after exercise across white muscle cell membranes in rainbow trout

1996 ◽  
Vol 271 (3) ◽  
pp. R738-R750 ◽  
Author(s):  
Y. Wang ◽  
G. J. Heigenhauser ◽  
C. M. Wood
Keyword(s):  
Membrane Potential ◽  
Cell Membrane ◽  
Intracellular Ph ◽  
Muscle Cell ◽  
Cell Membranes ◽  
White Muscle ◽  
Extracellular Ph ◽  
Posterior Portion ◽  
Arterial Inflow ◽  
Muscle Cell Membrane

Manipulations of pH and electrical gradients in a perfused preparation were used to analyze the factors controlling ammonia distribution and flux in trout white muscle after exercise. Trout were exercised to exhaustion, and then an isolated-perfused white muscle preparation with discrete arterial inflow and venous outflow was made from the posterior portion of the tail. The tail-trunks were perfused with low (7.4)-, medium (7.9)-, and high (8.4)-pH saline, achieved by varying HCO3- concentration ([HCO3-]) at constant Pco2. Intracellular and extracellular pH, ammonia, CO2, K+, Na+, and Cl- were measured. Muscle intracellular pH was not affected by changes in extracellular pH. Increasing extracellular pH caused a decrease in the transmembrane NH3 partial pressure (PNH3) gradient and a decrease in ammonia efflux. When extracellular K+ concentration was increased from 3.5 to 15 mM in the medium-pH group, a depolarization of the muscle cell membrane potential from -92 to -60 mV and a 0.1-unit depression in intracellular pH occurred. Ammonia efflux increased despite a marked reduction in the PNH3 gradient. Amiloride (10(-4) M) had no effect, indicating that Na+/H(+)-NH4+ exchange does not participate in ammonia transport in this system. A comparison of observed intracellular-to-extracellular ammonia distribution ratios with those modeled according to either pH or Nernst potential distributions supports a model in which ammonia distribution across white muscle cell membranes is affected by both pH and electrical gradients, indicating that the membranes are permeable to both NH3 and NH4+. Membrane potential, acting to retain high levels of NH4+ in the intracellular compartment, appears to have the dominant influence during the postexercise period. However, at rest, the pH gradient may be more important, resulting in much lower intracellular ammonia levels and distribution ratios. We speculate that the muscle cell membrane NH3-to-NH4+ permeability ratio in trout may change between the rest and postexercise condition.

Multifunctional gold nanoparticles as smart nanovehicles with enhanced tumour-targeting abilities for intracellular pH mapping and in vivo MR/fluorescence imaging

Nanoscale ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 2002-2010 ◽  
Author(s):  
Kang-Kang Yu ◽  
Kun Li ◽  
Chun-Yan Lu ◽  
Yong-Mei Xie ◽  
Yan-Hong Liu ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Fluorescence Imaging ◽  
Intracellular Ph ◽  
Living Cells ◽  
Tumour Targeting ◽  
Tumour Imaging ◽  
Pathological Changes

A number of multimodal agents have been developed for tumour imaging and diagnosis, but most of them cannot be used to study the detailed physiological or pathological changes in living cells at the same time.

scholarly journals Shedding light on the mitochondrial matrix through a functional membrane transporter

2020 ◽  
Vol 11 (4) ◽  
pp. 1052-1065 ◽  
Author(s):  
Alberto Blázquez-Moraleja ◽  
Ines Sáenz-de-Santa María ◽  
María D. Chiara ◽  
Delia Álvarez-Fernández ◽  
Inmaculada García-Moreno ◽  
...  
Keyword(s):  
Membrane Potential ◽  
Mitochondrial Membrane ◽  
Living Cells ◽  
Membrane Transporter ◽  
Mitochondrial Matrix ◽  
Functional Membrane

A BODIPY derivative of carnitine enters mitochondria regardless of their membrane potential and in an enantioselective way through a specific mitochondrial membrane transporter in living cells.

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