1. Published Work
Jahnke, J.P.; Terrell, J.L.; Smith, A.M.; Cheng, X.; Stratis-
Cullum, D.N. Influences of Adhesion Variability on the “Living”
Dynamics of Filamentous Bacteria in Microfluidic Channels.
Molecules 2016, 21, 985.
Abstract
Bacteria have a promising future as sensors or
components in bioengineered devices due to the relative
ease of which their genome can be manipulated.
However, attempting to quantify and control the growth of
surface-bound filamentous bacteria is an area of study
which invites further investigation. The growth of these
filaments as a result of their binding properties could
prove to be extremely useful in the building and
maintenance of biostructures. In this study, we examine
how filamentous E. coli respond to various surface
conditions with a focus on buckling and length of
individual cells. We find that on certain surfaces,
filamentous cells align and extend for multiple growth
cycles before buckling occurs. The greatest challenge in
keeping cells in line is that as filaments elongate,
buckling becomes more likely. By adjusting the surface
properties, we are able to control the binding strength of
cells in order to prolong the buckling of cells at greater
lengths. In finding a set of conditions which foster growth
of straight filaments, we gain greater insight into
controlling the shape of the cells for use in bioengineered
devices.
Experiment
• Filamentation is a
result of the inhibition
of cell division, leading
to cells up to 50x
longer than ordinary.
• Attachment strength
should affect cell
length and shape and
can be altered using
fimbriae-mannose
interactions.
Results
• Data was collected by imaging an area for two hours,
and was analyzed by tracing bacteria using ImageJ.
Conclusion
• Surface-bound cells grow longer than those in solution.
• Fim+ E. coli grow longest on man3+ surfaces, which also
have the greatest attachment strength.
• Buckling of fim+ cells occurs faster and to a greater
degree on man3+ versus man1 and man0.
• Fim- cells have least amount of interaction and grow
straighter, but not as long.
• Shear has little effect on the growth of the filaments
Student: Austin M. Smith, austin.smith2@utsa.edu Mentor: Justin P. Jahnke, justin.jahnke2.ctr@mail.mil
Alignment of Filamentous Bacteria under Flow
• Microfluidic devices were used to observe the effects
of flow rate on filaments.
• Devices were prepared with weak (man0), medium
(man1), or strong (man3+) binding substrates.
Fimbriated (fim+) & unfimbriated (fim-) E. coli were
tested.
Shear Effects
• Initial tests showed
shear to have
minimal effect on the
terminal length and
buckling of the cells.
• Terminal length
increases with surface
interaction strength
• Buckling increases with
surface interaction strength
Surface Interactions
20µm20µm