The Release of Holospora obtusa from Paramecium caudatum Observed with a New Device for Extended In Vivo Microscopy

ABSTRACT The macronudeus‐specilic bacterium Holospora obtusa is released from its host cell Paramecium caudatum generally after a preceding cell division. Before division, most infectious forms of the bacteria can be found in a connecting strand of the dividing macronucleus. This connecting strand is deformed and finally expelled as a whole from the daughter cells. This process was observed and photographed with a simple device allowing observations for a long lime under a microscope without damage to the living cells. Key words. Bacterium, cytoproct, defecation, infection, macronucleus, symbiosis.