Methanogenic archaea

Joblin, K. N.

doi:10.1007/1-4020-3791-0_4

Cited by 44 publications

(38 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Those that have been cultured are assigned to only seven species. These are Methanobacterium formicicum (33), Methanobacterium bryantii (16), Methanobrevibacter ruminantium (43), Methanobrevibacter millerae (36), Methanobrevibacter olleyae (36), Methanomicrobium mobile (35), and Methanoculleus olentangyi (16). Methanosarcina spp.…”

mentioning

confidence: 99%

“…have also been cultured from the rumen (1, 34) but are not normally a major part of the archaeal community. In addition, Methanobrevibacter smithii (16) has been reported as being isolated from the rumen, but this is likely to be a strain more closely related to M. millerae (M. Kirs and P. H. Janssen, unpublished data).…”

mentioning

confidence: 99%

“…This remains to be resolved. However, members of the order Methanococcales have not been cultured from the rumen (16).…”

mentioning

confidence: 99%

“…(1,34) and Methanoculleus olentangyi (16). The isolation of a microorganism from an environment indicates its presence at the time of sampling, but unless abundance is quantified, it is not possible to make statements regarding the numerical significance the organism has in the community from which it was cultured.…”

mentioning

confidence: 99%

See 3 more Smart Citations

Structure of the Archaeal Community of the Rumen

Janssen

Kirs

2008

Appl Environ Microbiol

534

472

View full text Add to dashboard Cite

Members of the domain Archaea contribute about 0.3 to 3.3% of the microbial small subunit (16S and 18S) rRNA in the rumen (22,39,60). Archaea have a range of different metabolisms and are found in many habitats (6), but those known to exist in the rumen are strictly anaerobic methanogens. Yanagita et al. (59) observed that 2.8 to 4.0% of ruminal microorganisms displayed autofluorescence characteristic of F 420 , a methanogen cofactor, able to be seen under UV illumination during microscopy. Taken together with the small subunit rRNA abundance data, this suggests that a large part of the archaeal population is made up of methanogens. Most species of methanogens can grow using H 2 and often formate as their energy sources and use the electrons derived from H 2 (or formate) to reduce CO 2 to CH 4 . Some species can grow with methyl groups, oxidizing some to CO 2 to produce electrons that are used to reduce further methyl groups to methane. A few species can grow with acetate, effectively dissimilating acetate to CH 4 and CO 2 . However, acetate is not metabolized to CH 4 to any significant extent in the rumen (13). This is probably because the rate of passage of rumen contents through the rumen is greater than the growth rate of acetateutilizing methanogens (53).In a normally functioning rumen, proteins and polymeric carbohydrates, which usually make up the largest part of the incoming feed, are fermented by a mixed microbial community to volatile fatty acids (VFAs), NH 4 ϩ , CO 2 , and H 2 . The hydrogen is metabolized by the methanogens. The VFAs are taken up by the animal across the rumen wall and serve as major carbon and energy sources for the ruminant. A part of the VFAs, undigested feed components, and microbial cells leave the rumen and enter the rest of the animal's digestive tract. The central role of H 2 in the rumen fermentation (12) means that, although methanogenic archaea make up only a small part of the rumen microbial biomass, they play an important role in rumen function and animal nutrition. Efficient H 2 removal leads to a nutritionally more favorable pattern of VFA formation and to an increased rate of fermentation by eliminating the inhibitory effect of H 2 on the microbial fermentation (26, 53).The rumen can be simplistically described as an open system with discontinuous solid (feed) and liquid (saliva and drinking water) inputs and multiple fractions that have different turnover rates (53). The methanogens in the rumen are found free in the rumen fluid, attached to particulate material and rumen protozoa, associated as endosymbionts within rumen protozoa, and attached to the rumen epithelium. The methanogens associated with these different fractions can be expected to have different growth rates since they will be removed from the rumen at different rates. In addition, the animal itself and the feed also influence the rate of passage of digesta through the rumen system (25). These different habitats may allow niche division among the methanogens and may explain some of the observed phyloge...

show abstract

mentioning

confidence: 99%

mentioning

confidence: 99%

“…This remains to be resolved. However, members of the order Methanococcales have not been cultured from the rumen (16).…”

mentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

Structure of the Archaeal Community of the Rumen

Janssen

Kirs

2008

Appl Environ Microbiol

534

472

View full text Add to dashboard Cite

show abstract

“…Symbiotic relationships are known between Archaea and ciliates (van Hoek et al, 2000), sponges (Preston et al, 1996) and even terrestrial ruminants (Joblin, 2005), defining a key role for Archaea in supporting eukaryotes through symbioses. It is unlikely that archaeal symbioses were present in Dorvillea sp.…”

Section: Archaea In Food Websmentioning

confidence: 99%

Archaea in metazoan diets: implications for food webs and biogeochemical cycling

et al. 2012

View full text Add to dashboard Cite

Although the importance of trophic linkages, including 'top-down forcing', on energy flow and ecosystem productivity is recognized, the influence of metazoan grazing on Archaea and the biogeochemical processes that they mediate is unknown. Here, we test if: (1) Archaea provide a food source sufficient to allow metazoan fauna to complete their life cycle; (2) neutral lipid biomarkers (including crocetane) can be used to identify Archaea consumers; and (3) archaeal aggregates are a dietary source for methane seep metazoans. In the laboratory, we demonstrated that a dorvilleid polychaete, Ophryotrocha labronica, can complete its life cycle on two strains of Euryarchaeota with the same growth rate as when fed bacterial and eukaryotic food. Archaea were therefore confirmed as a digestible and nutritious food source sufficient to sustain metazoan populations. Both strains of Euryarchaeota used as food sources had unique lipids that were not incorporated into O. labronica tissues. At methane seeps, sulfate-reducing bacteria that form aggregations and live syntrophically with anaerobic-methane oxidizing Archaea contain isotopically and structurally unique fatty acids (FAs). These biomarkers were incorporated into tissues of an endolithofaunal dorvilleid polychaete species from Costa Rica (mean bulk d 13 C ¼ À92±4%; polar lipids À116%) documenting consumption of archaeal-bacterial aggregates. FA composition of additional softsediment methane seep species from Oregon and California provided evidence that consumption of archaeal-bacterial aggregates is widespread at methane seeps. This work is the first to show that Archaea are consumed by heterotrophic metazoans, a trophic process we coin as 'archivory'.

show abstract

Structural determination of archaeal UDP‐N‐acetylglucosamine 4‐epimerase from Methanobrevibacter ruminantium M1 in complex with the bacterial cell wall intermediate UDP‐N‐acetylmuramic acid

et al. 2018

View full text Add to dashboard Cite

The crystal structure of UDP-N-acetylglucosamine 4-epimerase (UDP-GlcNAc 4-epimerase;WbpP; EC 5.1.3.7), from the archaeal methanogen Methanobrevibacter ruminantium strain M1, was determined to a resolution of 1.65 Å. The structure, with a single monomer in the crystallographic asymmetric unit, contained a conserved N-terminal Rossmann-fold for nucleotide binding and an active site positioned in the C-terminus. UDP-GlcNAc 4-epimerase is a member of the short-chain dehydrogenases/reductases superfamily, sharing sequence motifs and structural elements characteristic of this family of oxidoreductases and bacterial 4-epimerases. The protein was co-crystallized with coenzyme NADH and UDP-N-acetylmuramic acid, the latter an unintended inclusion and well known product of the bacterial enzyme MurB and a critical intermediate for bacterial cell wall synthesis. This is a non-native UDP sugar amongst archaea and was most likely incorporated from the E. coli expression host during purification of the recombinant enzyme. K E Y W O R D S 4-epimerase, EPZ, Methanobrevibacter, Pseudomurein, UDP-GlcNAc 4-epimerase, UDP-Nacetylglucosamine, UDP-N-acetylmuramic acid, WbpP

show abstract

Methanogenic archaea

Cited by 44 publications

References 24 publications

Structure of the Archaeal Community of the Rumen

Structure of the Archaeal Community of the Rumen

Archaea in metazoan diets: implications for food webs and biogeochemical cycling

Structural determination of archaeal UDP‐N‐acetylglucosamine 4‐epimerase from Methanobrevibacter ruminantium M1 in complex with the bacterial cell wall intermediate UDP‐N‐acetylmuramic acid

Contact Info

Product

Resources

About