期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1980
卷号：77
期号：5
页码：2470-2473
DOI：10.1073/pnas.77.5.2470
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：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 approximately 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.
