Giant bacterium (Epulopiscium fishelsoni ) influences digestive enzyme activity of an herbivorous surgeonfish (Acanthurus nigrofuscus)

Peggy E. Pollak, Linn W Montgomery

Research output: Contribution to journalArticle

9 Scopus citations


Giant bacteria (Epulopiscium fishelsoni) dominate the intestinal microbiota of brown surgeonfish, Acanthurus nigrofuscus, and reduce activity of the host's intestinal amylase, protease and lipase at physiologically relevant pH. Bacteria reduced activity of host amylase and protease directly at pH 6-8, and reduced pH-sensitive lipase activity indirectly by locally reducing pH in gut fluids. Inhibition of enzyme activity is inconsistent with a mutualistic role for the microbes relative to these host enzymes. However, high lipase activity at pH ~ 6, the pH where bacteria are dense, indicates that the bacteria counteract suppression of host lipase and contribute to lipid digestion.

Original languageEnglish (US)
Pages (from-to)657-662
Number of pages6
JournalComparative Biochemistry and Physiology -- Part A: Physiology
Issue number4
StatePublished - 1994



  • Acanthurus nigrofuscus
  • Digestive enzyme
  • Epulopiscium fishelsoni

ASJC Scopus subject areas

  • Physiology
  • Molecular Biology
  • Biochemistry

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