Comparison between time-resolved extra- and intracellular pH changes of Halobacterium salinarum upon irradiation
✍ Scribed by H. Urano
- Book ID
- 104373237
- Publisher
- Elsevier Science
- Year
- 1998
- Tongue
- English
- Weight
- 455 KB
- Volume
- 42
- Category
- Article
- ISSN
- 1011-1344
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✦ Synopsis
Time-resolved intracellular pH changes of H&bacterium scrlinarum Pho8 1BR (bR +, hR-) and L33 (bR-, hR' ) cells upon irradiation were measured with the fluorescent pH probe 2',7'-bis-(carboxyethyl)-5 (6)-carboxyfluorescein (BCECF). These pH changes were complementary to the extracellular pH changes measured with fuorescein in high-buffer basal salt and consistent with proton movement. In lowbuffer basal salt, however, the PhoSlBR cells showed a monotonic alkalization inside and a transient acidification followed by alkalization outside; they were not complementary to each other. In the case of L33 cells, the complementary pH changes of the two sides were shown in highly buffered solution, but not shown in low buffer. These results suggest that (i) the gated secondary proton inflow induced by the electrochemical proton gradients would depend on buffer outside; (ii) the gated proton inflow cannot be detected inside the cells with BCECF, especially in low-buffer basal salt; (iii) therefore, the discrepancy between pH changes of the two sides may be caused by the gated proton inflow.
0 1998 Elscvier Science S.A.