Marine Biology

, Volume 107, Issue 2, pp 291–296 | Cite as

Symbiosis within a symbiosis: Intracellular bacteria within the endosymbiotic protistNephromyces

  • M. B. Saffo


The marine protistNephromyces Giard, 1888 is a chronic endosymbiont of molgulid tunicates. Ultrastructural and cytochemical studies of this protist, isolated from molgulid hosts collected from the Pacific, Atlantic and Gulf Coasts of the United States, indicate thatNephromyces is itself chronically infected with Gramnegative, intracellular bacteria. Molgulid tunicates are thus the locus of a nested,tripartite endosymbiosis. Intracellular bacteria are present in both trophic and reproductive stages ofNephromyces, suggesting that the bacterial-Nephromyces symbiosis is an hereditary association. The presence of endosymbionts inNephromyces raises the possibility that some ofNephromyces' metabolic characteristics, in particular its high urate oxidase activity, might be supplied not byNephromyces itself, but rather by its intracellular bacteria, possibly functioning as peroxisomal analogues.


United States Oxidase Activity Gulf Coast Reproductive Stage Metabolic Characteristic 
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Copyright information

© Springer-Verlag 1990

Authors and Affiliations

  • M. B. Saffo
    • 1
  1. 1.Institute of Marine SciencesUniversity of CaliforniaSanta CruzUSA

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