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Gaines A, Ludovice M, Xu J, Zanghi M, Meinersmann RJ, Berrang M, Daley W, Britton D. The dialogue between protozoa and bacteria in a microfluidic device. PLoS One 2019; 14:e0222484. [PMID: 31596855 PMCID: PMC6784911 DOI: 10.1371/journal.pone.0222484] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Accepted: 08/30/2019] [Indexed: 01/28/2023] Open
Abstract
In nature, protozoa play a major role in controlling bacterial populations. This paper proposes a microfluidic device for the study of protozoa behaviors change due to their chemotactic response in the presence of bacterial cells. A three-channel microfluidic device was designed using a nitrocellulose membrane into which channels were cut using a laser cutter. The membrane was sandwiched between two glass slides; a Euglena suspension was then allowed to flow through the central channel. The two side channels were filled with either, 0.1% peptone as a negative control, or a Listeria suspension respectively. The membrane design prevented direct interaction but allowed Euglena cells to detect Listeria cells as secretions diffused through the nitrocellulose membrane. A significant number of Euglena cells migrated toward the chambers near the bacterial cells, indicating a positive chemotactic response of Euglena toward chemical cues released from Listeria cells. Filtrates collected from Listeria suspension with a series of molecular weight cutoffs (3k, 10k and 100k) were examined in Euglena chemotaxis tests. Euglena cells were attracted to all filtrates collected from the membrane filtration with different molecular weight cutoffs, suggesting small molecules from Listeria might be the chemical cues to attract protozoa. Headspace volatile organic compounds (VOC) released from Listeria were collected, spiked to 0.1% peptone and tested as the chemotactic effectors. It was discovered that the Euglena cells responded quickly to Listeria VOCs including decanal, 3,5- dimethylbenzaldehyde, ethyl acetate, indicating bacterial VOCs were used by Euglena to track the location of bacteria.
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Affiliation(s)
- Anna Gaines
- Aerospace, Transportation and Advanced Systems Laboratory, Georgia Tech Research Institute, Georgia Institute of Technology, Atlanta, Georgia, United States of America
| | - Miranda Ludovice
- Aerospace, Transportation and Advanced Systems Laboratory, Georgia Tech Research Institute, Georgia Institute of Technology, Atlanta, Georgia, United States of America
| | - Jie Xu
- Aerospace, Transportation and Advanced Systems Laboratory, Georgia Tech Research Institute, Georgia Institute of Technology, Atlanta, Georgia, United States of America
| | - Marc Zanghi
- Aerospace, Transportation and Advanced Systems Laboratory, Georgia Tech Research Institute, Georgia Institute of Technology, Atlanta, Georgia, United States of America
| | - Richard J. Meinersmann
- Richard B. Russell Research Center, Agricultural Research Service, United States Department of Agriculture, Athens, Georgia, United States of America
| | - Mark Berrang
- Richard B. Russell Research Center, Agricultural Research Service, United States Department of Agriculture, Athens, Georgia, United States of America
| | - Wayne Daley
- Aerospace, Transportation and Advanced Systems Laboratory, Georgia Tech Research Institute, Georgia Institute of Technology, Atlanta, Georgia, United States of America
| | - Doug Britton
- Aerospace, Transportation and Advanced Systems Laboratory, Georgia Tech Research Institute, Georgia Institute of Technology, Atlanta, Georgia, United States of America
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