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Lipid remodeling in Rhodopseudomonas palustris TIE-1 upon loss of hopanoids and hopanoid methylation

Neubauer, C. and Dalleska, N. F. and Cowley, E. S. and Shikuma, N. J. and Wu, C.-H. and Sessions, A. L. and Newman, D. K. (2015) Lipid remodeling in Rhodopseudomonas palustris TIE-1 upon loss of hopanoids and hopanoid methylation. Geobiology, 13 (5). pp. 443-453. ISSN 1472-4677. http://resolver.caltech.edu/CaltechAUTHORS:20150504-103056372

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Abstract

The sedimentary record of molecular fossils (biomarkers) can potentially provide important insights into the composition of ancient organisms; however, it only captures a small portion of their original lipid content. To interpret what remains, it is important to consider the potential for functional overlap between different lipids in living cells, and how the presence of one type might impact the abundance of another. Hopanoids are a diverse class of steroid analogs made by bacteria and found in soils, sediments, and sedimentary rocks. Here, we examine the trade-off between hopanoid production and that of other membrane lipids. We compare lipidomes of the metabolically versatile α-proteobacterium Rhodopseudomonas palustris TIE-1 and two hopanoid mutants, detecting native hopanoids simultaneously with other types of polar lipids by electrospray ionization mass spectrometry. In all strains, the phospholipids contain high levels of unsaturated fatty acids (often >80 %). The degree to which unsaturated fatty acids are modified to cyclopropyl fatty acids varies by phospholipid class. Deletion of the capacity for hopanoid production is accompanied by substantive changes to the lipidome, including a several-fold rise of cardiolipins. Deletion of the ability to make methylated hopanoids has a more subtle effect; however, under photoautotrophic growth conditions, tetrahymanols are upregulated twofold. Together, these results illustrate that the ‘lipid fingerprint’ produced by a micro-organism can vary depending on the growth condition or loss of single genes, reminding us that the absence of a biomarker does not necessarily imply the absence of a particular source organism.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1111/gbi.12143DOIArticle
http://onlinelibrary.wiley.com/doi/10.1111/gbi.12143/abstractPublisherArticle
http://onlinelibrary.wiley.com/doi/10.1111/gbi.12143/suppinfoPublisherSupporting Information
ORCID:
AuthorORCID
Dalleska, N. F.0000-0002-2059-1587
Sessions, A. L.0000-0001-6120-2763
Newman, D. K.0000-0003-1647-1918
Additional Information:© 2015 John Wiley & Sons Ltd. Received 4 February 2015; accepted 23 March 2015. Article first published online: 29 Apr. 2015. We thank members of the Newman laboratory and Ian Booth at the University of Aberdeen for comments on the manuscript. Mona Shahgholi at the Multiuser Mass Spectrometry Lab at Caltech provided important support in the beginning of the project. This work was supported by grants from NASA (NNX12AD93G), the National Science Foundation (1224158), the Howard Hughes Medical Institute (DKN), an Agouron Postdoctoral Fellowship and an EMBO Long-Term Fellowship (CN). DKN is an HHMI Investigator. LC-MS data collection and analysis were performed in the Caltech Environmental Analysis Center.
Funders:
Funding AgencyGrant Number
NASANNX12AD93G
NSF1224158
Howard Hughes Medical Institute (HHMI)UNSPECIFIED
Agouron InstituteUNSPECIFIED
European Molecular Biology Organization (EMBO)UNSPECIFIED
Record Number:CaltechAUTHORS:20150504-103056372
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20150504-103056372
Official Citation:Neubauer, C., Dalleska, N. F., Cowley, E. S., Shikuma, N. J., Wu, C.-H., Sessions, A. L. and Newman, D. K. (2015), Lipid remodeling in Rhodopseudomonas palustris TIE-1 upon loss of hopanoids and hopanoid methylation. Geobiology, 13: 443–453. doi: 10.1111/gbi.12143
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:57188
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:04 May 2015 17:50
Last Modified:24 Oct 2017 16:37

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