Using Caenorhabditis elegans and an engineered bacterium to dissect host pathogen avoidance strategies
Abstract
Little is known about how host-pathogen interactions determine avoidance strategies. Bacterial pathogens can infect Caenorhabditis elegans via ingestion. In its natural environment, C. elegans is attracted to bacterial food sources that produce small molecules called chemoattractants. In some instances, chemoattractant are produced by bacterial pathogens. Upon ingesting these pathogens, C. elegans can become infected, and can subsequently perish. However, through aversive learning, C. elegans can learn to associate these chemoattractants with harm. This ultimately causes the worms to avoid consuming the pathogen. Evolutionary constraints have likely shaped the interplay of the attraction and learning dynamics between pathogenic bacteria and C. elegans. However, this remains largely unexplored. Using bacteria engineered to express an acylhomoserine lactone chemoattractant and a nematicidal protein, we explored how manipulating the amount of attractant produced by the bacteria affects learning and intoxication in C. elegans. We observed that the percentage of intoxicated worms is maximized when they are exposed to intermediate concentration of the chemoattractant. Towards explaining this observation, we measured the feeding rate of C. elegans fed on the engineered bacteria. We observed a significant reduction in feeding rate that apparently coincided with aversive learning. Our results aid our understanding of the dynamics that determine behavioral avoidance in C. elegans.
Faculty Sponsors
Dr. Robert P. Smith, Dr. Christopher Blanar
Project Type
Event
Location
Alvin Shermany Library
Start Date
4-5-2019 1:00 PM
End Date
4-5-2019 5:00 PM
Using Caenorhabditis elegans and an engineered bacterium to dissect host pathogen avoidance strategies
Alvin Shermany Library
Little is known about how host-pathogen interactions determine avoidance strategies. Bacterial pathogens can infect Caenorhabditis elegans via ingestion. In its natural environment, C. elegans is attracted to bacterial food sources that produce small molecules called chemoattractants. In some instances, chemoattractant are produced by bacterial pathogens. Upon ingesting these pathogens, C. elegans can become infected, and can subsequently perish. However, through aversive learning, C. elegans can learn to associate these chemoattractants with harm. This ultimately causes the worms to avoid consuming the pathogen. Evolutionary constraints have likely shaped the interplay of the attraction and learning dynamics between pathogenic bacteria and C. elegans. However, this remains largely unexplored. Using bacteria engineered to express an acylhomoserine lactone chemoattractant and a nematicidal protein, we explored how manipulating the amount of attractant produced by the bacteria affects learning and intoxication in C. elegans. We observed that the percentage of intoxicated worms is maximized when they are exposed to intermediate concentration of the chemoattractant. Towards explaining this observation, we measured the feeding rate of C. elegans fed on the engineered bacteria. We observed a significant reduction in feeding rate that apparently coincided with aversive learning. Our results aid our understanding of the dynamics that determine behavioral avoidance in C. elegans.
