Team:BCCS-Bristol/Modeling-Parameters

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Modelling Parameters


Bacteria

Attribute Value Strain Justification Reference
Length2ìmMG1655Values come from the University of Alberta’s datasheet on MG1655, produced to aid modelling. There is variability in size between strains - for instance, AW405 length varies between 1.5±0.2ìm. But University of Alberta datasheet is specifically for MG1655.http://redpoll.pharmacy.ualberta.ca/CCDB/cgi-bin/STAT_NEW.cgi
Diameter0.8ìmMG1655http://redpoll.pharmacy.ualberta.ca/CCDB/cgi-bin/STAT_NEW.cgi
ShapeCircle r =0.714ìmMG1655Actually rod-like. A circle with r= 0.714ìm will have equivalent surface area to rod-like.http://redpoll.pharmacy.ualberta.ca/CCDB/cgi-bin/STAT_NEW.cgi
Mass1.02x10-13gMG1655Given 1x10-12g for cell wet weight. Dividing this by gravity (=9.81) gives mass. http://redpoll.pharmacy.ualberta.ca/CCDB/cgi-bin/STAT_NEW.cgi
Swimming Speed50ìm.s-1MG1655University Alberta's datasheet gives 50ìms-1. However, Swimming speed is affected by:
    • Viscosity (as viscosity increases the speed increases to some maximum, then decreases as the viscosity increases further. E.coli (strain:KL227 of length: 1.0ìm and diameter: 0.5ìm) maximum speed occurs at viscosity 8cp. Suggested to be because higher viscosity provides increased energy supply.
    • Temperature
    • Culture medium
    • Vary strain to strain.
    • Experimental methods

Many papers give different and variable speeds (mainly for AW405 ~20ìms-1). The speed itself is nearly uniform during the run. May need to measure experimentally, don't know under what conditions University of Alberta. Alberta value is higher than other values, but probably because MG1655 is a motile strain. \"||http://redpoll.pharmacy.ualberta.ca/CCDB/cgi-bin/STAT_NEW.cgi Biotechnology and Bioengineering, Volume 51, Issue 1 (p 120-125) http://www3.interscience.wiley.com/cgi-bin/fulltext/71003069/PDFSTART

Run Tumble motion

Swimming Machinery

Attribute Value Strain Justification Reference
Average thrust 0.41±0.23 pNAW4050.41±0.23 pN ( standard deviation for 32 bacteria) was obtained from strain AW405, a strain which has provided the majority of our previous parameters but is not MG1655 which is more motile. The value was obtained at 23ºC in viscosity 0.93 and 3.07 cP for motility buffer and motility buffer with 0.18% methylcellulose, respectively. The standard deviation is not used as the speed is fixed at 50µm/s. 0.57pN is the average thrust generated in strain HCB30 (a non tumbling strain). The thrust value was obtained when the imposed flow (U) U=0 at 23ºC. O.41pN was calculated using the resistance force theory treating the flagellar bundle as a single filament. The body was assumed to be prolate elipsoid using values roughly similar to ours, 2μm for length and 0.86μm for diameter.Darnton, N. C., Turner. L., Rojevsky. S., Berg. H. C., 2007 On Torque and tumbling in swimming Escherichia coli J. Bacteriol 189(5) 1756-1764. http://jb.asm.org/cgi/reprint/189/5/1756 Swimming efficiency of bacterium E. coli. http://www.pnas.org/content/103/37/13712.full.pdf+html


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