1999 Fiscal Year Final Research Report Summary
Microscopic Fluid Dynamic Research for Locomotion of Bacterium with Flagella
| Project/Area Number |
09450077
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Fluid engineering
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| Research Institution | Tottori University |
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Principal Investigator |
TAKANO Yasunari Tottori University, Department of Mechanical Engineering, Professor, 工学部, 教授 (00089111)
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| Co-Investigator(Kenkyū-buntansha) |
GOTO Tomonobu Tottori University, Department of Mechanical Engineering, Lecturer, 工学部, 講師 (00260654)
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| Project Period (FY) |
1997 – 1999
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| Keywords | Swimming Bacteria / Helical Flagella / Bacterium Motion / Flagellar Fluid Dynamics / Dark-Field Microscope / Vibrio alginolyticus / Salmonella |
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| Research Abstract |
In the present investigation, the locomotion of bacteria in water is not only analyzed applying several analytical approaches such as the resistive force theory, the boundary element method, and the slender body theory for Stokes flows, but also the swimming of Vibrio alginolyticus is observed using a dark-field biological microscope and is recorded by a video cassette recorder. The results of observation is compared with the analytical results.
Formulations based on the resistive force theory are performed for motion of bacteria with rotating flagella assuming that a bacterium consists of a spherical or spheroidal cell body and rigid helical flagella. Numerical examples show that the trajectory of the bacterium follows several patterns of helix such as a single, a double and a disorted helix according to configuration of the flagelum located on the cell surface.
Computational procedures are also developed to calculate locomotion of the bacteria by applying the boundary element method (BEM) as well as the slender body theory for Stokes flow. The computational method based on BEM is most accurate but needs expensive computation time.
The swimming motion of Vibrio alginolyticus, a kind of monotrishously flagellated bacteria is observed using a dark-field biological microscope with CCD camera as well as a video cassette recorder. The image of the bacteria swimming zigzag is tracked manually. The swimming speed and rotation rate of the cell body are measured from the video data. Linear relations between the speed and the rotation rate of the cell body are obtained from the observation.
The observed relations are compared with those obtained from results of BEM for shape parameters of the observed bacteria. The agreement is very good between them. This fact leads to the conclusion that the mechanism of locomotion of monotrishously flagellated bacteria is well described by fluid dynamics at low Reynolds number.
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