title: Functional responses of methanogenic archaea to syntrophic growth.
abstract: Methanococcus maripaludis grown syntrophically with Desulfovibrio vulgaris was compared with M. maripaludis monocultures grown under hydrogen limitation using transcriptional, proteomic and metabolite analyses. These measurements indicate a decrease in transcript abundance for energy-consuming biosynthetic functions in syntrophically grown M. maripaludis, with an increase in transcript abundance for genes involved in the energy-generating central pathway for methanogenesis. Compared with growth in monoculture under hydrogen limitation, the response of paralogous genes, such as those coding for hydrogenases, often diverged, with transcripts of one variant increasing in relative abundance, whereas the other was little changed or significantly decreased in abundance. A common theme was an apparent increase in transcripts for functions using H(2) directly as reductant, versus those using the reduced deazaflavin (coenzyme F(420)). The greater importance of direct reduction by H(2) was supported by improved syntrophic growth of a deletion mutant in an F(420)-dependent dehydrogenase of M. maripaludis. These data suggest that paralogous genes enable the methanogen to adapt to changing substrate availability, sustaining it under environmental conditions that are often near the thermodynamic threshold for growth. Additionally, the discovery of interspecies alanine transfer adds another metabolic dimension to this environmentally relevant mutualism.
authors: Department of Civil and Environmental Engineering, University of Washington, Seattle, WA, USA.
authors: Christopher B
authors: CB
authors: Walker
authors: Alyssa M
authors: AM
authors: Redding-Johanson
authors: Edward E
authors: EE
authors: Baidoo
authors: Lara
authors: L
authors: Rajeev
authors: Zhili
authors: Z
authors: He
authors: Erik L
authors: EL
authors: Hendrickson
authors: Marcin P
authors: MP
authors: Joachimiak
authors: Sergey
authors: S
authors: Stolyar
authors: Adam P
authors: AP
authors: Arkin
authors: John A
authors: JA
authors: Leigh
authors: Jizhong
authors: J
authors: Zhou
authors: Jay D
authors: JD
authors: Keasling
authors: Aindrila
authors: A
authors: Mukhopadhyay
authors: David A
authors: DA
authors: Stahl
mesh_terms: D016969:Desulfovibrio vulgaris / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D004734:Energy Metabolism; D006859:Hydrogen / Q000378:metabolism; D019344:Lactic Acid / Q000378:metabolism; D008697:Methane / Q000378:metabolism; D017017:Methanococcus / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D010088:Oxidoreductases / Q000235:genetics / Q000378:metabolism; D040901:Proteomics
chemical_list: D019344:Lactic Acid; D006859:Hydrogen; D010088:Oxidoreductases; D008697:Methane