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BEGIN:VEVENT
DTSTAMP:20261020T171032Z
LAST-MODIFIED:20150429T165014Z
DTSTART:20150430T150000Z
DTEND:20150430T160000Z
UID:event1443@bu.edu
URL:http://physics.bu.edu/internal/events/show/1443
SUMMARY: The Influence of Morphology on the Swimming Behavior of  Helicobac
	ter Pylori
DESCRIPTION:Featuring Joseph Hardcastle\n\nPart of the Departmental Seminar
	s.\n\nDissertation Committee: Rama Bansil\, Steve Ahlen\, Shyamsunder Erram
	illi\, Kirill Korolev\, Pankaj Mehta\n\nAbstract:\n\nBacterial motility pla
	ys a key role in a bacterium’s ability to successful colonize a host envi
	ronment. However\, the role of cell morphology and its link to motility is 
	not well understood. Helicobacter Pylori\, the bacterium that causes stomac
	h ulcers and cancer\, is a prime example of this. This bacterium has a heli
	cal cell shape that has long been believed to provide an advantage in penet
	rating the viscous mucus layer protecting the stomach lining\, its niche en
	vironment. To explore this we have performed live cell bacteria tracking us
	ing optical microscopy of helical cells and mutants that have a straight ro
	d shape. Analysis of bacterial swimming trajectories indicates that H. Pylo
	ri uses a run-reverse swimming behavior\, with bacteria swimming in straigh
	t trajectories\, runs\, interrupted by reversals events\, during which they
	 reverse their swimming direction by ~180o.  This run-reverse behavior when
	 bacteria swim in mucin solutions\, with reversals decreasing and stops inc
	reasing. Comparing the swimming of bacteria with different cell shapes show
	s shape plays little role in altering swimming behavior\, but can result in
	 increased swimming speeds. To obtain further insight we modeled bacterial 
	swimming using several different hydrodynamic models. Experimental and mode
	ling results agree that a helical cell shape can increase swimming speeds b
	y ~10% depending on cell body parameters.  Lastly\, we explore how changing
	 the number of flagella impacts swimming speed.  We find that modulating fl
	agella number results in larger changes in swimming speed than altering cel
	l shape\, with increasing number of flagella resulting in increasing swimmi
	ng speeds.  Taken together our results show that the helical cell shape of 
	H. Pylori does play a role in bacterial swimming\, however compared to othe
	r factors\, such as flagella number\, this effect seems to be small.  This 
	poses an interesting question as to whether cell shape may play another rol
	e in bacterial colonization which is yet unknown.\n\n![Hardcastle] (/resour
	ces/event-image/1443/6fb2202_small)
LOCATION:PRB 365\, 3 Cummington Mall\, 02215
STATUS:CONFIRMED
CLASS:PUBLIC
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