Automated separation of C. elegans variably colonized by a bacterial pathogen

Area of Science:

• Microbiology
• Immunology
• Genetics

Background:

• Caenorhabditis elegans immune responses are documented but initiation triggers remain unclear.
• Key possibilities for immune response initiation include pathogen-associated molecular patterns (PAMPs) recognition or damage detection.
• Differentiating these triggers requires separating pathogen exposure from infection-induced damage.

Purpose of the Study:

• To investigate the relationship between intestinal pathogen colonization and immune response induction in C. elegans.
• To differentiate whether C. elegans immune responses are initiated by pathogen recognition or tissue damage.
• To explore an alternative application of the wormsorter for pathogen colonization studies.

Main Methods:

• Utilized a wormsorter, typically used for fluorescent reporter sorting, to separate C. elegans based on GFP-expressing pathogen colonization levels.
• Separated worms into populations with extensive Pseudomonas aeruginosa colonization versus those with minimal or no colonization despite similar exposure.
• Assessed transcriptional immune responses in these distinct worm populations.

Main Results:

• Demonstrated the ability to sort C. elegans based on the degree of pathogen colonization using a wormsorter.
• Showed that extensive pathogen colonization and associated damage can be dissociated from immune response induction.
• Results indicate a dissociation between pathogen load and transcriptional immune response activation.

Conclusions:

• The findings support pathogen recognition as a primary trigger for C. elegans immune responses.
• The study validates a novel application of the wormsorter for dissecting host-pathogen interactions.
• This work provides evidence for PAMPs-mediated immunity initiation in C. elegans.