Interrelations between populations of methanogenic archaea and sulfate-reducing bacteria in the human colon.
In humans, CH4 is produced in the colon by methanogenic archaea and is detected in breath samples from approximately 50% of healthy adults, identified as CH4-excretors. Methanogenesis and sulfate reduction have been described as two mutually exclusive processes, potentially regulated by sulfate availability. To determine whether microbial population balances reflected these apparently co-regulated activities, we compared sulfate-reducing bacteria, methanogenic archaea, sulfate and sulfide concentrations in faeces of 10 CH4-excretors (CH4+) and 9 non-CH4-excretors (CH4-). The mean +/- SE of the logarithm of methanogenic archaea per gram wet weight were 9.0 +/- 0.2 and 4.0 +/- 0.7 for CH4+ and CH4-, respectively (P < 0.001). Sulfate-reducing bacterial counts were 6.5 +/- 0.1 and 7.3 +/- 0.2, respectively (P < 0.001). Fecal sulfate and sulfide concentrations did not differ between groups. These results suggest that a competitive interrelation between methanogenic archaea and sulfate-reducing bacteria occurs in the human colon. However, it does not lead to a complete exclusion of the two populations.
Pochart
P
P
Conservatoire National des Arts et Métiers, Chaire de Biologie, Paris, France.
Doré
J
J
Lémann
F
F
Goderel
I
I
Rambaud
J C
JC
D000293:Adolescent; D000328:Adult; D001419:Bacteria / Q000378:metabolism; D003106:Colon / Q000378:metabolism / Q000382:microbiology*; D019605:Euryarchaeota / Q000302:isolation & purification*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010084:Oxidation-Reduction; D013431:Sulfates / Q000378:metabolism*
D013431:Sulfates