User:Kayladanesh/sandbox-first draft
Intracellular pH (pHi)[edit]
From original article: "Intracellular pH (pHi) is the measure of...pHi of 6.8-7.1)". There is also pH variation across different organelles, which can span from around 4.5 to 8.0.[1][2] The pH within a particular organelle is tailored for its specific function. For example, phagocytes and lysosomes have a relatively low internal pH.[1][3] pHi can be measured in a number of different ways, and pHi is closely regulated in order to ensure proper cellular function, controlled cell growth, and normal cellular processes.[4][5][6]
Methods for Measuring Intracellular pH[edit]
There are several ways in which intracellular pH (pHi) can be measured. The main ways in which pHi can be measured is with a microelectrode or dye that is sensitive to pH, or with nuclear magnetic resonance techniques.[7][8]
Microelectrode[edit]
The microelectrode method for measuring pHi consists of placing a very small electrode into the cell’s cytosol by making a very small hole in the plasma membrane of the cell.[8] Since the microelectrode has fluid with a high H+ concentration inside, relative to the outside of the electrode, there is a potential created due to the pH discrepancy between the inside and outside of the electrode.[7][8] From this voltage difference, and a predetermined pH for the fluid inside the electrode, one an determine the intracellular pH (pHi) of the cell of interest. [8]
Fluorescence Spectroscopy[edit]
Another way to measure Intracellular pH (pHi) is with dyes that are sensitive to pH, and fluoresce differently at various pH values.[3][9] This technique, often referred to as fluorescence spectroscopy, consists of adding this special dye to the cytosol of a cell.[7][8] By exciting the dye in the cell with energy from light, and measuring the wavelength of light released by the photon as it returns to its native energy state, one can determine the intracellular pH of the given cell.[7][8]
Nuclear Magnetic Resonance[edit]
In addition to using pH-sensitive electrodes and dyes to measure pHi, Nuclear Magnetic Resonance (NMR) spectroscopy can also be used to quantify pHi.[8] NMR, typically speaking, reveals information about the inside of a cell by placing the cell in an environment with a potent magnetic field.[7][8] Based on the ratio between the concentrations of protonated, compared to deprotonated forms of phosphate compounds in a given cell, the internal pH of the cell can be determined.[7] Additionally, NMR may also be used to reveal the presence of intracellular sodium, which can also provide information about the pHi.[10]
Summary of Measurement Methods[edit]
Overall, all three methods have their own advantages and disadvantages. Using dyes is perhaps the easiest and fairly precise, while NMR presents the challenge of being relatively less precise.[7] Furthermore, using a microelectrode may be challenging in situations where the cells are too small, or the intactness of the cell membrane should remain undisturbed.[8]
How Intracellular pH is maintained[edit]
From original article: "Intracellular pH is typically lower...and pHi decreases." Since biological cells contain fluid that can act as a buffer, pHi can be maintained fairly well within a certain range.[11] Cells adjust their pHi accordingly upon an increase in acidity or basicity with the help of CO2 or HCO3- sensors present in the membrane of the cell.[4] These sensors can permit H+ to pass through the cell membrane accordingly, allowing for pHi to be interrelated with extracellular pH in this respect.[12]
Additional Information[edit]
From original article: "Lymphocytes maintain ... USA."
References[edit]
- ^ a b Asokan, Aravind; Cho, Moo J. (April 2002). "Exploitation of intracellular pH gradients in the cellular delivery of macromolecules". Journal of Pharmaceutical Sciences. 91 (4): 903–913. ISSN 0022-3549. PMID 11948528.
- ^ Proksch, Ehrhardt (September 2018). "pH in nature, humans and skin". The Journal of Dermatology. 45 (9): 1044–1052. doi:10.1111/1346-8138.14489. ISSN 1346-8138. PMID 29863755.
- ^ a b Nunes, Paula; Guido, Daniele; Demaurex, Nicolas (2015-12-07). "Measuring Phagosome pH by Ratiometric Fluorescence Microscopy". Journal of Visualized Experiments: JoVE (106): e53402. doi:10.3791/53402. ISSN 1940-087X. PMID 26710109.
- ^ a b Boron WF (December 2004). "Regulation of intracellular pH". Adv Physiol Educ. 28 (1–4): 160–79. doi:10.1152/advan.00045.2004. PMID 15545345.
- ^ Demuth, Caspar; Varonier, Joel; Jossen, Valentin; Eibl, Regine; Eibl, Dieter (May 2016). "Novel probes for pH and dissolved oxygen measurements in cultivations from millilitre to benchtop scale". Applied Microbiology and Biotechnology. 100 (9): 3853–3863. doi:10.1007/s00253-016-7412-0. ISSN 1432-0614. PMID 26995606.
- ^ Parks, Scott K.; Pouysségur, Jacques (April 2017). "Targeting pH regulating proteins for cancer therapy-Progress and limitations". Seminars in Cancer Biology. 43: 66–73. doi:10.1016/j.semcancer.2017.01.007. ISSN 1096-3650. PMID 28137473.
- ^ a b c d e f g Roos, A.; Boron, W. F. (April 1981). "Intracellular pH". Physiological Reviews. 61 (2): 296–434. doi:10.1152/physrev.1981.61.2.296. ISSN 0031-9333. PMID 7012859.
- ^ a b c d e f g h i Loiselle FB, Casey JR (2010). "Measurement of Intracellular pH". Methods Mol. Biol. 637: 311–31. doi:10.1007/978-1-60761-700-6_17. PMID 20419443.
- ^ Specht, Elizabeth A.; Braselmann, Esther; Palmer, Amy E. (October 2017). "A Critical and Comparative Review of Fluorescent Tools for Live-Cell Imaging". Annual Review of Physiology. 79: 93–117. doi:10.1146/annurev-physiol-022516-034055. ISSN 1545-1585. PMID 27860833.
- ^ Eliav, U.; Navon, G. (February 2016). "Sodium NMR/MRI for anisotropic systems". NMR in biomedicine. 29 (2): 144–152. doi:10.1002/nbm.3331. ISSN 1099-1492. PMID 26105084.
- ^ Slonczewski, Joan L.; Fujisawa, Makoto; Dopson, Mark; Krulwich, Terry A. (2009). "Cytoplasmic pH measurement and homeostasis in bacteria and archaea". Advances in Microbial Physiology. 55: 1–79, 317. doi:10.1016/S0065-2911(09)05501-5. ISSN 2162-5468. PMID 19573695.
- ^ Jensen, F. B. (November 2004). "Red blood cell pH, the Bohr effect, and other oxygenation-linked phenomena in blood O2 and CO2 transport". Acta Physiologica Scandinavica. 182 (3): 215–227. doi:10.1111/j.1365-201X.2004.01361.x. ISSN 0001-6772. PMID 15491402.