Document Detail

Carbon and nitrogen assimilation in deep subseafloor microbial cells.
MedLine Citation:
PMID:  21987801     Owner:  NLM     Status:  MEDLINE    
Remarkable numbers of microbial cells have been observed in global shallow to deep subseafloor sediments. Accumulating evidence indicates that deep and ancient sediments harbor living microbial life, where the flux of nutrients and energy are extremely low. However, their physiology and energy requirements remain largely unknown. We used stable isotope tracer incubation and nanometer-scale secondary ion MS to investigate the dynamics of carbon and nitrogen assimilation activities in individual microbial cells from 219-m-deep lower Pleistocene (460,000 y old) sediments from the northwestern Pacific off the Shimokita Peninsula of Japan. Sediment samples were incubated in vitro with (13)C- and/or (15)N-labeled glucose, pyruvate, acetate, bicarbonate, methane, ammonium, and amino acids. Significant incorporation of (13)C and/or (15)N and growth occurred in response to glucose, pyruvate, and amino acids (∼76% of total cells), whereas acetate and bicarbonate were incorporated without fostering growth. Among those substrates, a maximum substrate assimilation rate was observed at 67 × 10(-18) mol/cell per d with bicarbonate. Neither carbon assimilation nor growth was evident in response to methane. The atomic ratios between nitrogen incorporated from ammonium and the total cellular nitrogen consistently exceeded the ratios of carbon, suggesting that subseafloor microbes preferentially require nitrogen assimilation for the recovery in vitro. Our results showed that the most deeply buried subseafloor sedimentary microbes maintain potentials for metabolic activities and that growth is generally limited by energy but not by the availability of C and N compounds.
Yuki Morono; Takeshi Terada; Manabu Nishizawa; Motoo Ito; François Hillion; Naoto Takahata; Yuji Sano; Fumio Inagaki
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2011-10-10
Journal Detail:
Title:  Proceedings of the National Academy of Sciences of the United States of America     Volume:  108     ISSN:  1091-6490     ISO Abbreviation:  Proc. Natl. Acad. Sci. U.S.A.     Publication Date:  2011 Nov 
Date Detail:
Created Date:  2011-11-09     Completed Date:  2012-01-25     Revised Date:  2013-06-27    
Medline Journal Info:
Nlm Unique ID:  7505876     Medline TA:  Proc Natl Acad Sci U S A     Country:  United States    
Other Details:
Languages:  eng     Pagination:  18295-300     Citation Subset:  IM    
Kochi Institute for Core Sample Research, Japan Agency for Earth-Marine Science and Technology (JAMSTEC), Nankoku, Kochi 783-8502, Japan.
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MeSH Terms
Archaea / genetics,  metabolism
Bacteria / genetics,  metabolism
Carbon / metabolism*
In Situ Hybridization, Fluorescence
Nitrogen / metabolism*
Seawater / microbiology*
Spectrometry, Mass, Secondary Ion / methods
Water Microbiology*
Reg. No./Substance:
7440-44-0/Carbon; 7727-37-9/Nitrogen
Comment In:
Proc Natl Acad Sci U S A. 2011 Nov 8;108(45):18193-4   [PMID:  22031692 ]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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