Measurement of the Internal pH of Yeast Spores by 31P Nuclear Magnetic Resonance
Abstract
The asci and single spores of the yeast Pichia pastoris were examined by using 31P NMR. The pH within the spores was determined from the pH-dependent chemical shifts of the internal orthophosphate (Pi) peaks. In spectra of asci, two internal Pi peaks corresponding to two compartments were observed. Only small variations in the internal pH values were found upon incubation of the asci in buffers ranging in pH from 3 to 10. For this range in external pH, the internal pH values calculated from the Pi chemical shifts were 5.5-6.3 and 5.1-5.9. The two internal Pi peaks, which have line widths of approx 60 Hz, have been assigned to spore and epiplasmic compartments, respectively. Spectra of single spores revealed only one Pi peak, and, upon germination of either the single spores or asci, only this Pi peak disappeared. Peaks corresponding to ATP were not found in the dormant spores and asci but did appear upon germination. These NMR studies show the yeast spore to have a mobile and relatively acidic interior.
Additional Information
© 1980 National Academy of Sciences. Contributed by Robert G. Shulman, January 25, 1980. The publication costs of this article were defrayed in part by page charge payment. This article must therefore be hereby marked "advertisement" in accordance with 18 U. S. C. §1734 solely to indicate this fact.Attached Files
Published - BARpnas80.pdf
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Additional details
- PMCID
- PMC349421
- Eprint ID
- 636
- Resolver ID
- CaltechAUTHORS:BARpnas80
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2005-09-08Created from EPrint's datestamp field
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2019-10-02Created from EPrint's last_modified field