Probing the Subcellular Localization of Hopanoid Lipids in Bacteria Using NanoSIMS
Abstract
The organization of lipids within biological membranes is poorly understood. Some studies have suggested lipids group into microdomains within cells, but the evidence remains controversial due to non-native imaging techniques. A recently developed NanoSIMS technique indicated that sphingolipids group into microdomains within membranes of human fibroblast cells. We extended this NanoSIMS approach to study the localization of hopanoid lipids in bacterial cells by developing a stable isotope labeling method to directly detect subcellular localization of specific lipids in bacteria with ca. 60 nm resolution. Because of the relatively small size of bacterial cells and the relative abundance of hopanoid lipids in membranes, we employed a primary ^2H-label to maximize our limit of detection. This approach permitted the analysis of multiple stable isotope labels within the same sample, enabling visualization of subcellular lipid microdomains within different cell types using a secondary label to mark the growing end of the cell. Using this technique, we demonstrate subcellular localization of hopanoid lipids within alpha-proteobacterial and cyanobacterial cells. Further, we provide evidence of hopanoid lipid domains in between cells of the filamentous cyanobacterium Nostoc punctiforme. More broadly, our method provides a means to image lipid microdomains in a wide range of cell types and test hypotheses for their functions in membranes.
Additional Information
© 2014 Doughty et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Received August 13, 2013; Accepted November 22, 2013; Published January 7, 2014. Grants to D.K.N. from the Howard Hughes Medical Institute (HHMI) and the NASA Exobiology program (NNX12AD93G) supported this work. D.K.N. is an HHMI Investigator. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. We thank Dr. Chia-Hung Wu for generating mutant strains of R. palustris and assistance with mass spectrometric analysis and Dr. Gargi Kulkarni for help with mCherry fusion strain construction. We thank Dr. Yungbin Guan, Prof. John Eiler and the Center for Microanalysis at the California Institute of Technology for assistance with NanoSIMS.Attached Files
Published - journal.pone.0084455.pdf
Supplemental Material - journal.pone.0084455.s001.pdf
Supplemental Material - journal.pone.0084455.s002.pdf
Supplemental Material - journal.pone.0084455.s003.pdf
Supplemental Material - journal.pone.0084455.s004.pdf
Supplemental Material - journal.pone.0084455.s005.pdf
Supplemental Material - journal.pone.0084455.s006.pdf
Supplemental Material - journal.pone.0084455.s007.pdf
Supplemental Material - journal.pone.0084455.s008.pdf
Supplemental Material - journal.pone.0084455.s009.pdf
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Additional details
- PMCID
- PMC3883690
- Eprint ID
- 43703
- Resolver ID
- CaltechAUTHORS:20140206-114311185
- Howard Hughes Medical Institute (HHMI)
- NASA
- NNX12AD93G
- Created
-
2014-02-06Created from EPrint's datestamp field
- Updated
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2021-11-10Created from EPrint's last_modified field
- Caltech groups
- Division of Geological and Planetary Sciences