One of the most important emerging behaviors in biology is swarm formation. Many species of bacteria swarm, including species found in diverse soil and water environments such as Bacillus subtilis, Serratia liquefaciens, Proteus mirabilis, Pseudomonas aeruginosa, and Myxococcus xanthus. These and other swarming bacteria span the gamut of utility and range from innocuous carbon-cycle organisms to harmful pathogens. Swarming is observed in cells that are propelled by rotating flagella, by the secretion of slime, and by retracting type IV pili. Bacteria move on substrates and change their local environment in a way that improves cellular physical interaction and optimizes swarming. M. xanthus, a rod-shaped, Gram negative myxobacterium is able to glide on surfaces using two genetically independent yet cooperative A and S motility engines. These bacteria produce slime and move on slime tracks produced by other members of the colony. Remarkably, these bacteria also regularly reverse their gliding directions. The main goal of this proposal is to combine simulations using new three-dimensional multiscale modeling environment and specifically designed experiments to study basic coordination events of M. xanthus swarming, which is essential to understanding how millions of bacteria function in real environments. Specifically, we will study the role of flexibility of cells, viscosity of extracellular polysaccharide, slime adhesivity and directional reversals in resolving collisions, increasing alignment and optimizing swarming rate during swarming of mutant strains (A+S-) and ( A-S+) and wild type (A+S+) of M. xanthus. Predictive simulations will yield new biological hypotheses about M. Xanthus swarming because of the ability to conduct "experiments" in silico that are yet difficult (or impossible) to perform physically. A key aspect of this work will be to compare predictions obtained in silico with experimental observations. Study of the M. xanthus social interactions will provide an opportunity to gain fundamental insight into the biological response to how organisms discern, process, and respond to the chemical, physical, and biological cues present in their local environment.

Public Health Relevance

Many organisms colonize new territory by swarming in groups where the actions of the group are coordinated. Swarming bacteria span the gamut of utility and range from innocuous carbon-cycle organisms to harmful pathogens. We propose to use predictive simulations in concert with laboratory experiments to study the role of flexibility of cells, viscosity of extracellular polysaccharide, slime adhesivity and directional reversals in resolving collisions, increasing alignment and optimizing swarming rate during swarming of mutant strains and wild type of M. xanthus. This study of the M. xanthus social interactions will provide fundamental insight into the biological response to how organisms discern, process, and respond to the chemical, physical, and biological cues present in their local environment.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM100470-03
Application #
8471126
Study Section
Special Emphasis Panel (ZGM1-CBCB-5 (BM))
Program Officer
Gindhart, Joseph G
Project Start
2011-09-15
Project End
2014-05-31
Budget Start
2013-06-01
Budget End
2014-05-31
Support Year
3
Fiscal Year
2013
Total Cost
$250,479
Indirect Cost
$83,493
Name
University of Notre Dame
Department
Biostatistics & Other Math Sci
Type
Schools of Arts and Sciences
DUNS #
824910376
City
Notre Dame
State
IN
Country
United States
Zip Code
46556
Xu, Zhiliang; Chen, Xu-Yan; Liu, Yingjie (2014) A New Runge-Kutta Discontinuous Galerkin Method with Conservation Constraint to Improve CFL Condition for Solving Conservation Laws. J Comput Phys 278:348-377
Chen, Jianxu; Harvey, Cameron W; Alber, Mark S et al. (2014) A matching model based on earth mover's distance for tracking Myxococcus xanthus. Med Image Comput Comput Assist Interv 17:113-20
Chen, Jianxu; Harvey, Cameron W; Alber, Mark S et al. (2014) A matching model based on earth mover's distance for tracking Myxococcus xanthus. Med Image Comput Comput Assist Interv 17:113-20
Buchmann, Amy; Alber, Mark; Zartman, Jeremiah J (2014) Sizing it up: the mechanical feedback hypothesis of organ growth regulation. Semin Cell Dev Biol 35:73-81
Harvey, Cameron W; Madukoma, Chinedu S; Mahserejian, Shant et al. (2014) Cell division resets polarity and motility for the bacterium Myxococcus xanthus. J Bacteriol 196:3853-61
Harvey, Cameron W; Alber, Mark; Tsimring, Lev S et al. (2013) Continuum modeling of clustering of myxobacteria. New J Phys 15:
Zhang, Yong-Tao; Alber, Mark S; Newman, Stuart A (2013) Mathematical modeling of vertebrate limb development. Math Biosci 243:1-17
Gejji, Richard; Kazmierczak, Bogdan; Alber, Mark (2012) Classification and stability of global inhomogeneous solutions of a macroscopic model of cell motion. Math Biosci 238:21-31
Xu, Zhiliang; Christley, Scott; Lioi, Joshua et al. (2012) Multiscale model of fibrin accumulation on the blood clot surface and platelet dynamics. Methods Cell Biol 110:367-88