Microbial biomass turnover times and clues to cellular protein repair in energy-limited deep Baltic Sea sedimentsShow others and affiliations
2019 (English)In: FEMS Microbiology Ecology, ISSN 0168-6496, E-ISSN 1574-6941, Vol. 95, no 6, article id fiz068Article in journal (Refereed) Published
Abstract [en]
The discovery of active microbial life deeply buried beneath the seafloor has opened important questions: how do microorganisms cope with extreme energy limitation, what is their metabolic activity, and how do they repair damages to essential biomolecules? We used a D:L-amino acid model to calculate microbial biomass turnover times. We used a metagenome and metatranscriptome analysis to investigate the distribution of the gene that encodes Protein-L-iso aspartate(D-aspartate) O-methyltransferase (PCMT), an enzyme which recognizes damaged L-isoapartyl and D-aspartyl residues in proteins and catalyzes their repair. Sediment was retrieved during the Integrated Ocean Drilling Program (IODP) Expedition 347 from Landsort Deep and the Little Belt in the Baltic Sea. The study covers the period from the Baltic Ice Lake ca. 13 000 years ago to the present. Our results provide new knowledge on microbial biomass turnover times and protein repair in relation to different regimes of organic matter input. For the first time, we show that the PCMT gene was widely distributed and expressed among phylogenetically diverse groups of microorganisms. Our findings suggest that microbial communities are capable of repairing D-amino acids within proteins using energy obtained from the degradation of a mixture of labile compounds in microbial necromass and more recalcitrant organic matter.
Place, publisher, year, edition, pages
Oxford University Press, 2019. Vol. 95, no 6, article id fiz068
Keywords [en]
D:L-amino acid model, Glacial-Holocene transition, Protein-L-isoaspartate(D-aspartate) O-methyltransferase, biomass turnover times, marine deep biosphere, microbial necromass, organic matter diagenesis, protein repair
National Category
Environmental Sciences
Research subject
Baltic and East European studies
Identifiers
URN: urn:nbn:se:sh:diva-38303DOI: 10.1093/femsec/fiz068ISI: 000474762800012PubMedID: 31095297Scopus ID: 2-s2.0-85067268290OAI: oai:DiVA.org:sh-38303DiVA, id: diva2:1323189
Part of project
IODP Expedition 347 Baltic Sea Paleoenvironment, Swedish Research CouncilLate Pleistocene and Holocene climate forcing on the Baltic Sea, The Foundation for Baltic and East European Studies
Funder
EU, FP7, Seventh Framework Programme, 294200The Foundation for Baltic and East European Studies, 75/20142019-06-112019-06-112022-03-02Bibliographically approved