The secretory vesicle in living Paramecium is acidic.

G. R. Busch, B. H. Satir

Research output: Contribution to journalArticlepeer-review

7 Scopus citations


In Paramecium, secretory proteins are packaged within membrane-bounded vesicles in a condensed form. This form expands when the proteins are released. We have now determined that a proton gradient is present in the secretory vesicles of living Paramecium. Acridine Orange, used as an in vivo indicator of acidic compartments, stained the secretory vesicles in both wild-type and mutant cells. Addition of the two agents that dissipate proton gradients (protonophores), namely, 2,4-dinitrophenol (DNP) and carbonylcyanide m-chlorophenylhydrazone (CCCP), eliminated this staining. Washed cells re-established their intravesicular acidity. Effects of sodium azide on vesicular acidity suggest that proton transport in these vesicles involves an ATP-dependent mechanism.

Original languageEnglish (US)
Pages (from-to)197-203
Number of pages7
JournalJournal of cell science
Volume92 ( Pt 2)
StatePublished - Feb 1989

ASJC Scopus subject areas

  • Cell Biology


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