A microfluidic chemotaxis assay to study microbial behavior in diffusing nutrient patches

Seymour, JR; Ahmed, T; Marcos; Stocker, R

A microfluidic chemotaxis assay to study microbial behavior in diffusing nutrient patches

Seymour, JR

Ahmed, T Marcos Stocker, R

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Publication Type:: Journal Article
Citation:: Limnology and Oceanography: Methods, 2008, 6 (9), pp. 477 - 488
Issue Date:: 2008-09-01

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Field	Value	Language
dc.contributor.author	Seymour, JR https://orcid.org/0000-0002-3745-6541	en_US
dc.contributor.author	Ahmed, T	en_US
dc.contributor.author	Marcos	en_US
dc.contributor.author	Stocker, R	en_US
dc.date.issued	2008-09-01	en_US
dc.identifier.citation	Limnology and Oceanography: Methods, 2008, 6 (9), pp. 477 - 488	en_US
dc.identifier.uri	http://hdl.handle.net/10453/8517
dc.description.abstract	© 2014, by the Association for the Sciences of Limnology and Oceanography. The nutrient environment experienced by planktonic microorganisms is patchy at spatiotemporal scales commensurate with their motility (μm - cm), and the efficiency with which chemotactic microbes can exploit this heterogeneous seascape influences trophodynamics and nutrient cycling rates in aquatic environments. Yet, methodological limitations have largely prevented direct examinations of microbial behavior within heterogeneous microenvironments. We used soft lithography to fabricate a microfluidic-based chemotaxis assay to study the foraging response of aquatic microbes to diffusing microscale nutrient patches. The transparency, biocompatibility, and simplicity of microfluidic devices make them ideally suited for microbial ecology studies. A microinjector was used to create a 300 μm-wide nutrient band, simulating a pulse release of solutes. The chemotactic response of microbes to the diffusing patch was measured at the population and single-cell level. In contrast to traditional chemotaxis assays, this technique permits the assessment and quantification of chemotaxis toward a potential attractant in real time, enabling rapid screening of multiple chemicals. Furthermore, detailed information on chemotactic behavior can be obtained by tracking individual organisms. Here, we applied this microassay to study the chemotactic behavior of a range of aquatic microorganisms, including three marine bacterial isolates, a species of phagotrophic flagellate, and a species of phytoplankton. Each organism exhibited a rapid chemotactic response to a variety of chemical compounds, suggesting that many marine microbes are adapted to life within patchy microenvironments. The chemotaxis assay described here was found to be a flexible platform for studying both the specific case of microbes foraging within patchy habitats and as a broadly applicable tool for rapidly assessing and quantifying microbial chemotaxis.	en_US
dc.relation.ispartof	Limnology and Oceanography: Methods	en_US
dc.relation.isbasedon	10.4319/lom.2008.6.477	en_US
dc.subject.classification	Marine Biology & Hydrobiology	en_US
dc.title	A microfluidic chemotaxis assay to study microbial behavior in diffusing nutrient patches	en_US
dc.type	Journal Article
utslib.citation.volume	9	en_US
utslib.citation.volume	6	en_US
utslib.for	0602 Ecology	en_US
utslib.for	04 Earth Sciences	en_US
utslib.for	06 Biological Sciences	en_US
pubs.embargo.period	Not known	en_US
pubs.organisational-group	/University of Technology Sydney
pubs.organisational-group	/University of Technology Sydney/Faculty of Science
pubs.organisational-group	/University of Technology Sydney/Strength - C3 - Climate Change Cluster
utslib.copyright.status	open_access
pubs.issue	9	en_US
pubs.publication-status	Published	en_US
pubs.volume	6	en_US

Abstract:

© 2014, by the Association for the Sciences of Limnology and Oceanography. The nutrient environment experienced by planktonic microorganisms is patchy at spatiotemporal scales commensurate with their motility (μm - cm), and the efficiency with which chemotactic microbes can exploit this heterogeneous seascape influences trophodynamics and nutrient cycling rates in aquatic environments. Yet, methodological limitations have largely prevented direct examinations of microbial behavior within heterogeneous microenvironments. We used soft lithography to fabricate a microfluidic-based chemotaxis assay to study the foraging response of aquatic microbes to diffusing microscale nutrient patches. The transparency, biocompatibility, and simplicity of microfluidic devices make them ideally suited for microbial ecology studies. A microinjector was used to create a 300 μm-wide nutrient band, simulating a pulse release of solutes. The chemotactic response of microbes to the diffusing patch was measured at the population and single-cell level. In contrast to traditional chemotaxis assays, this technique permits the assessment and quantification of chemotaxis toward a potential attractant in real time, enabling rapid screening of multiple chemicals. Furthermore, detailed information on chemotactic behavior can be obtained by tracking individual organisms. Here, we applied this microassay to study the chemotactic behavior of a range of aquatic microorganisms, including three marine bacterial isolates, a species of phagotrophic flagellate, and a species of phytoplankton. Each organism exhibited a rapid chemotactic response to a variety of chemical compounds, suggesting that many marine microbes are adapted to life within patchy microenvironments. The chemotaxis assay described here was found to be a flexible platform for studying both the specific case of microbes foraging within patchy habitats and as a broadly applicable tool for rapidly assessing and quantifying microbial chemotaxis.

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http://hdl.handle.net/10453/8517