Using GFP-expressing Green E. coli Cells to Study the Digestive System of Caenorhabditis elegans Worms

Introduction: As people age, their digestive system tends to decrease in efficient activity and function. The nematode C. elegans is a valuable model system for studying the aging process. In this study, we employed E. coli cells expressing the green fluorescent protein GFP to study the digestive system of the worms and to define its correlation with aging.

Methods: We have generated recombinant E. coli cells expressing a GST fusion protein containing the green fluorescent protein GFP.  These E. coli cells were used to feed C. elegans worms of different ages for various periods of time. Intake and digestion of the E. coli cells were monitored under fluorescent microscope.  The pharynx pumping rates and defecation intervals were also recorded. 

Results:  We observed distinct patterns of GFP fluorescence in the intestine and body of the C. elegans worms.  This correlates well with their development stages and ages. 

Conclusions:  The decline in digestive system activity in the worms can be effectively monitored by using GFP-expressing E. coli cells.  We thus provided a unique tool to study the digestive system and aging of C. elegans worms. 

Funding was provided by NIH grants 5P20RR016478, NIH HL079441, and HL094591.