Methane oxidation in termite hindguts: absence of evidence and evidence of absence.
A steep oxygen gradient and the presence of methane render the hindgut internal periphery of termites a potential habitat for aerobic methane-oxidizing bacteria. However, methane emissions of various termites increased, if at all, only slightly when termites were exposed to an anoxic (nitrogen) atmosphere, and (14)CH(4) added to the air headspace over live termites was not converted to (14)CO(2). Evidence for the absence of methane oxidation in living termites was corroborated by the failure to detect pmoA, the marker gene for particulate methane monooxygenase, in hindgut DNA extracts of all termites investigated. This adds robustness to our concept of the degradation network in the termite hindgut and eliminates the gut itself as a potential sink of this important greenhouse gas.
Pester
Michael
M
Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch-Strasse, 35043 Marburg, Germany. brune@mpi-marburg.mpg.de
Tholen
Anne
A
Friedrich
Michael W
MW
Brune
Andreas
A
D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics; D002245:Carbon Dioxide / Q000378:metabolism; D002250:Carbon Radioisotopes / Q000378:metabolism; D041981:Gastrointestinal Tract / Q000378:metabolism / Q000382:microbiology; D020049:Isoptera / Q000382:microbiology / Q000502:physiology*; D008697:Methane / Q000378:metabolism*; D010084:Oxidation-Reduction; D010105:Oxygenases / Q000235:genetics; D016133:Polymerase Chain Reaction
D001426:Bacterial Proteins; D002250:Carbon Radioisotopes; D002245:Carbon Dioxide; D010105:Oxygenases; C021555:methane monooxygenase; D008697:Methane