An impaired metabolic response to hydrostatic pressure explains Alcanivorax borkumensis recorded distribution in the deep marine water column

Type
Article

Authors
Scoma, Alberto
Barbato, Marta
Borin, Sara
Daffonchio, Daniele
Boon, Nico

KAUST Department
Biological and Environmental Sciences and Engineering (BESE) Division
Bioscience Program

Online Publication Date
2016-08-12

Print Publication Date
2016-11

Date
2016-08-12

Abstract
Alcanivorax borkumensis is an ubiquitous model organism for hydrocarbonoclastic bacteria, which dominates polluted surface waters. Its negligible presence in oil-contaminated deep waters (as observed during the Deepwater Horizon accident) raises the hypothesis that it may lack adaptive mechanisms to hydrostatic pressure (HP). The type strain SK2 was tested under 0.1, 5 and 10 MPa (corresponding to surface water, 500 and 1000 m depth, respectively). While 5 MPa essentially inactivated SK2, further increase to 10 MPa triggered some resistance mechanism, as indicated by higher total and intact cell numbers. Under 10 MPa, SK2 upregulated the synthetic pathway of the osmolyte ectoine, whose concentration increased from 0.45 to 4.71 fmoles cell-1. Central biosynthetic pathways such as cell replication, glyoxylate and Krebs cycles, amino acids metabolism and fatty acids biosynthesis, but not β-oxidation, were upregulated or unaffected at 10 MPa, although total cell number was remarkably lower with respect to 0.1 MPa. Concomitantly, expression of more than 50% of SK2 genes was downregulated, including genes related to ATP generation, respiration and protein translation. Thus, A. borkumensis lacks proper adaptation to HP but activates resistance mechanisms. These consist in poorly efficient biosynthetic rather than energy-yielding degradation-related pathways, and suggest that HP does represent a major driver for its distribution at deep-sea.

Citation
Scoma A, Barbato M, Borin S, Daffonchio D, Boon N (2016) An impaired metabolic response to hydrostatic pressure explains Alcanivorax borkumensis recorded distribution in the deep marine water column. Scientific Reports 6: 31316. Available: http://dx.doi.org/10.1038/srep31316.

Acknowledgements
This work was funded by FP-7 project Kill Spill (No. 312139, “Integrated Biotechnological Solutions for Combating Marine Oil Spills”) and by the Geconcentreerde Onderzoeksactie (GOA) of Ghent University (BOF15/GOA/006). The authors thank the support of King Abdullah University of Science and Technology (baseline research funds to D.D.).

Publisher
Springer Nature

Journal
Scientific Reports

DOI
10.1038/srep31316

PubMed ID
27515484

Additional Links
http://www.nature.com/articles/srep31316

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