title: Studies on a macronuclear endosymbiont of Spirostomum ambiguum. I. Isolation of the microorganism from the macronucleus.
mesh_terms: D000818:Animals; D001419:Bacteria / Q000145:classification / Q000302:isolation & purification*; D002467:Cell Nucleus / Q000382:microbiology; D016798:Ciliophora / Q000382:microbiology*; D013559:Symbiosis