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VERSION:2.0
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BEGIN:VEVENT
DTSTAMP:20261018T231850Z
LAST-MODIFIED:20121116T203436Z
DTSTART:20121031T190000Z
DTEND:20121031T200000Z
UID:event1011@bu.edu
URL:http://physics.bu.edu/internal/events/show/1011
SUMMARY:Mobility of Helicobacter Pylori in Gels
DESCRIPTION:Featuring Joseph Hardcastle\n\nPart of the Preliminary Oral Exa
	m.\n\nExamining Committee:  Rama Bansil\, Steve Ahlen\, Shyam Erramill
	i\, Pankaj Mehta\nHelicobacter Pylori\, a helical bacterium with multiple p
	olar flagella\, colonizes the low pH gel environment of the human stomach a
	nd can cause gastric ulcers\, gastritis and cancer.  The issue of how 
	it moves in a viscoelastic gel is central to establishing an infection. Two
	 factors are believed to play a role in helping it deal with the low pH gel
	 environment.  In earlier work from our laboratory Celli et al showed 
	that this bacteria secretes urease which breaks down urea to produce NH3 le
	ading to elevation of pH and triggering a gel-sol transition in the mucin g
	el1.  This significantly decreases the viscoelastic nature of the envi
	ronment allowing the bacteria to swim freely.  In this presentation I 
	will address whether its helical body allows it to swim more effectively in
	 viscoelastic environments.  In order to study the effects of body sha
	pe on motility we have compared the wild type (helical) with straight rod m
	utants in gelatin solutions undergoing a sol –gel transformation.&nbs
	p; Gelatin allows for control of the gel properties using temperature and c
	oncentration while keeping the solution at suitable pH for the bacteria.&nb
	sp; Using video microscopy I have tracked the bacteria at different stages 
	of the sol – gel transition and been able to identify a change from a
	 translation+ rotation motion in gelatin solution to pure rotation slightly
	 below the gel point. Both cell types show decreased motility as the gel is
	 formed\, but wild type cells maintain a motility advantage over straight r
	od cells in all cases.  In order to understand this advantage I have m
	odeled the swimming of the bacteria in a pre-gel solution based on a resist
	ive force theory2. We also characterize the rotational motion by analyzing 
	bacteria that are stuck in the gel and do not translate.\n \nResearch 
	supported by NSF POLS.\n \n[1] Jonathan P. Celli\, Bradley S. Turner\,
	 Nezam H. Afdhal\, Sarah Keates\, Ionita Ghiran\, Ciaran P. Kelly\, Randy H
	. Ewoldt\, Gareth H. McKinley\, Peter So\, Shyamsunder Erramilli\, and Rama
	 Bansil\, PNAS 109\, 34 (2009)\n[2] Guanglai Li and Jay X. Tang\, Biophys. 
	J. 88\, 2726 (2006)
LOCATION:PRB 261\, 3 Cummington Mall\, 02215
STATUS:TENTATIVE
CLASS:PUBLIC
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