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Experimentally guided computational model discovers important elements for social behavior in myxobacteria.

Hendrata M, Yang Z, Lux R, Shi W - PLoS ONE (2011)

Bottom Line: The simulation is able to produce both gliding pattern and spontaneous aggregation center formation as observed in experiments.The model is tested against several known M. xanthus mutants and our modification of parameter values relevant for the individual mutants produces good phenotypic agreements.This outcome indicates the strong predictive potential of our model for the social behaviors of uncharacterized mutants and their expected phenotypes during development.

View Article: PubMed Central - PubMed

Affiliation: Department of Mathematics, California State University Los Angeles, Los Angeles, California, United States of America. mhendra@calstatela.edu

ABSTRACT
Identifying essential factors in cellular interactions and organized movement of cells is important in predicting behavioral phenotypes exhibited by many bacterial cells. We chose to study Myxococcus xanthus, a soil bacterium whose individual cell behavior changes while in groups, leading to spontaneous formation of aggregation center during the early stage of fruiting body development. In this paper, we develop a cell-based computational model that solely relies on experimentally determined parameters to investigate minimal elements required to produce the observed social behaviors in M. xanthus. The model verifies previously known essential parameters and identifies one novel parameter, the active turning, which we define as the ability and tendency of a cell to turn to a certain angle without the presence of any obvious external factors. The simulation is able to produce both gliding pattern and spontaneous aggregation center formation as observed in experiments. The model is tested against several known M. xanthus mutants and our modification of parameter values relevant for the individual mutants produces good phenotypic agreements. This outcome indicates the strong predictive potential of our model for the social behaviors of uncharacterized mutants and their expected phenotypes during development.

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The active turning event in M. xanthus.(A) Active turning is commonly observed in individual M. xanthus cells. A series of snapshots from a recorded experiment taken at time 0 second, 50 seconds, 100 seconds, 150 seconds and their overlap image shows how active turning angle  is determined. (B) The experimental value of the active turning frequency is normally distributed around 3 minutes per turn. (C) The experimental value of the active turning angle follows a normal distribution with a mean of approximately 30 degrees.
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pone-0022169-g002: The active turning event in M. xanthus.(A) Active turning is commonly observed in individual M. xanthus cells. A series of snapshots from a recorded experiment taken at time 0 second, 50 seconds, 100 seconds, 150 seconds and their overlap image shows how active turning angle is determined. (B) The experimental value of the active turning frequency is normally distributed around 3 minutes per turn. (C) The experimental value of the active turning angle follows a normal distribution with a mean of approximately 30 degrees.

Mentions: In order to improve the simulation and enable our model to fully represent M. xanthus gliding behaviors during development, we have identified one novel parameter that was overlooked before, the active turning. When single cells initially glide over agar surface, their movement paths do not always follow a straight line. In contrast, single cells are frequently found to change direction of movement without the presence of apparent external factors covered in the known parameters: collision, alignment with other cells, or following an existing EPS slime trail. We define this new cellular behavior as active turning. The active turning angle is measured as the angle between the cell long axis before and after one cell length movement (Fig. 2A). By examining the active turning events in hundreds of individual cells in recorded experiments, we find that the frequency of active turning is normally distributed with an average of approximately 3 minutes per turn (Fig. 2B). In addition, the turning angle is also normally distributed centered around 30 degrees and there is an equal chance for cells to either turn to the left or turn to the right (Fig. 2C).


Experimentally guided computational model discovers important elements for social behavior in myxobacteria.

Hendrata M, Yang Z, Lux R, Shi W - PLoS ONE (2011)

The active turning event in M. xanthus.(A) Active turning is commonly observed in individual M. xanthus cells. A series of snapshots from a recorded experiment taken at time 0 second, 50 seconds, 100 seconds, 150 seconds and their overlap image shows how active turning angle  is determined. (B) The experimental value of the active turning frequency is normally distributed around 3 minutes per turn. (C) The experimental value of the active turning angle follows a normal distribution with a mean of approximately 30 degrees.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3139613&req=5

pone-0022169-g002: The active turning event in M. xanthus.(A) Active turning is commonly observed in individual M. xanthus cells. A series of snapshots from a recorded experiment taken at time 0 second, 50 seconds, 100 seconds, 150 seconds and their overlap image shows how active turning angle is determined. (B) The experimental value of the active turning frequency is normally distributed around 3 minutes per turn. (C) The experimental value of the active turning angle follows a normal distribution with a mean of approximately 30 degrees.
Mentions: In order to improve the simulation and enable our model to fully represent M. xanthus gliding behaviors during development, we have identified one novel parameter that was overlooked before, the active turning. When single cells initially glide over agar surface, their movement paths do not always follow a straight line. In contrast, single cells are frequently found to change direction of movement without the presence of apparent external factors covered in the known parameters: collision, alignment with other cells, or following an existing EPS slime trail. We define this new cellular behavior as active turning. The active turning angle is measured as the angle between the cell long axis before and after one cell length movement (Fig. 2A). By examining the active turning events in hundreds of individual cells in recorded experiments, we find that the frequency of active turning is normally distributed with an average of approximately 3 minutes per turn (Fig. 2B). In addition, the turning angle is also normally distributed centered around 30 degrees and there is an equal chance for cells to either turn to the left or turn to the right (Fig. 2C).

Bottom Line: The simulation is able to produce both gliding pattern and spontaneous aggregation center formation as observed in experiments.The model is tested against several known M. xanthus mutants and our modification of parameter values relevant for the individual mutants produces good phenotypic agreements.This outcome indicates the strong predictive potential of our model for the social behaviors of uncharacterized mutants and their expected phenotypes during development.

View Article: PubMed Central - PubMed

Affiliation: Department of Mathematics, California State University Los Angeles, Los Angeles, California, United States of America. mhendra@calstatela.edu

ABSTRACT
Identifying essential factors in cellular interactions and organized movement of cells is important in predicting behavioral phenotypes exhibited by many bacterial cells. We chose to study Myxococcus xanthus, a soil bacterium whose individual cell behavior changes while in groups, leading to spontaneous formation of aggregation center during the early stage of fruiting body development. In this paper, we develop a cell-based computational model that solely relies on experimentally determined parameters to investigate minimal elements required to produce the observed social behaviors in M. xanthus. The model verifies previously known essential parameters and identifies one novel parameter, the active turning, which we define as the ability and tendency of a cell to turn to a certain angle without the presence of any obvious external factors. The simulation is able to produce both gliding pattern and spontaneous aggregation center formation as observed in experiments. The model is tested against several known M. xanthus mutants and our modification of parameter values relevant for the individual mutants produces good phenotypic agreements. This outcome indicates the strong predictive potential of our model for the social behaviors of uncharacterized mutants and their expected phenotypes during development.

Show MeSH