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Endosymbiotic Methanogenic Bacteria In Anaerobic Ciliates: Significance For the Growth Efficiency of the Host
Author(s) -
FENCHEL TOM,
FINLAY BLAND J.
Publication year - 1991
Publication title -
the journal of protozoology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.067
H-Index - 77
eISSN - 1550-7408
pISSN - 0022-3921
DOI - 10.1111/j.1550-7408.1991.tb04788.x
Subject(s) - methanogen , biology , bacteria , protozoa , microbiology and biotechnology , host (biology) , anaerobic exercise , food science , ecology , physiology , genetics
Endosymbiotic methanogenic bacteria of three species of anaerobic ciliates (Plagiopyla frontata, Metopus conforms , and M. palaeformis) were inactivated with the specific methanogen inhibitor 2‐bromoethanesulfonic acid. the absence of endosymbiont methanogens reduced growth rate and growth yield by about 30% in P. frontata and M. contortus , while no significant change in fitness was observed in M. palaeformis. In Plagiopyla the growth rate constant is not affected by an artificially increased pH 2 neither in normal nor in methanogen‐free ciliates. the energetic advantage conferred by endosymbiont methanogens in Plagiopyla and in Metopus contortus probably is due to excretion of organic material from the bacteria at the expense of bacterial reproduction. It is unlikely that the maintenance of a low pH 2 within the cells due to H 2 ‐consumption by the bacteria is important to the ciliates.