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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Methanogenic food web in the gut contents of methane-emitting earthworm Eudrilus eugeniae from Brazil

Full text
Author(s):
Schulz, Kristin [1] ; Hunger, Sindy [1] ; Brown, George G. [2] ; Tsai, Siu M. [3] ; Cerri, Carlos C. [3] ; Conrad, Ralf [4] ; Drake, Harold L. [1]
Total Authors: 7
Affiliation:
[1] Univ Bayreuth, Dept Ecol Microbiol, D-95440 Bayreuth - Germany
[2] Embrapa Florestas, Colombo - Brazil
[3] Univ Sao Paulo, Ctr Nucl Energy Agr, CENA USP, Sao Paulo - Brazil
[4] Max Planck Inst Terr Microbiol, D-35043 Marburg - Germany
Total Affiliations: 4
Document type: Journal article
Source: ISME Journal; v. 9, n. 8, p. 1778-1792, AUG 2015.
Web of Science Citations: 14
Abstract

The anoxic saccharide-rich conditions of the earthworm gut provide an ideal transient habitat for ingested microbes capable of anaerobiosis. It was recently discovered that the earthworm Eudrilus eugeniae from Brazil can emit methane (CH4) and that ingested methanogens might be associated with this emission. The objective of this study was to resolve trophic interactions of bacteria and methanogens in the methanogenic food web in the gut contents of E. eugeniae. RNA-based stable isotope probing of bacterial 16S rRNA as well as mcrA and mrtA (the alpha subunit of methyl-CoM reductase and its isoenzyme, respectively) of methanogens was performed with {[}C-13]-glucose as a model saccharide in the gut contents. Concomitant fermentations were augmented by the rapid consumption of glucose, yielding numerous products, including molecular hydrogen (H-2), carbon dioxide (CO2), formate, acetate, ethanol, lactate, succinate and propionate. Aeromonadaceae-affiliated facultative aerobes, and obligate anaerobes affiliated to Lachnospiraceae, Veillonellaceae and Ruminococcaceae were associated with the diverse fermentations. Methanogenesis was ongoing during incubations, and C-13-labeling of CH4 verified that supplemental {[}C-13]-glucose derived carbon was dissimilated to CH4. Hydrogenotrophic methanogens affiliated with Methanobacteriaceae and Methanoregulaceae were linked to methanogenesis, and acetogens related to Peptostreptoccocaceae were likewise found to be participants in the methanogenic food web. H-2 rather than acetate stimulated methanogenesis in the methanogenic gut content enrichments, and acetogens appeared to dissimilate supplemental H-2 to acetate in methanogenic enrichments. These findings provide insight on the processes and associated taxa potentially linked to methanogenesis and the turnover of organic carbon in the alimentary canal of methane-emitting E. eugeniae. (AU)

FAPESP's process: 11/50914-3 - The microbiome of Amazonian dark earth: structure and function of the microbial communities from rhizosphere and biochar associated to the biogeochemical cycles
Grantee:Tsai Siu Mui
Support Opportunities: BIOTA-FAPESP Program - Regular Research Grants
FAPESP's process: 08/58114-3 - Monitoring the microbial diversity and functional activities in response to land-use changes and deforestation under soybean and sugarcane cultivations
Grantee:Tsai Siu Mui
Support Opportunities: Research Program on Global Climate Change - Thematic Grants