In the second approach, L. reuteri was first allowed to produce reuterin in the presence of the 3-D colon cells (seeded into the wells), after which the cells were exposed to Salmonella. Here, the L. reuteri bacteria (in the presence of glycerol) produced reuterin in situ. In both approaches, non-reuterin exposed controls were also tested, and the effect of reuterin on a Salmonella population in the absence of host cells was assessed as well.
L. reuteri regulates response to infection
The results showed a reduction in the Salmonella population (without host cells) after one hour of exposure to a diluted supernatant containing reuterin. Further, the reuterin-containing ferment of L. reuteri was shown to significantly reduce adhesion, invasion and intracellular survival of Salmonella to 3-D colon cells, compared with an untreated control.
In an unexpected twist, the application of L. reuteri supernatant lacking glycerol actually stimulated adhesion, invasion and intracellular survival of Salmonella. The authors speculate that the stimulatory effect observed may have been due to low concentrations of acetic acid, previously shown to stimulate expression of Salmonella virulence-related genes.
Applying the second approach, live L. reuteri were incubated with 3-D epithelial cells and the medium supplemented with glycerol, allowing for in situ production of reuterin. The presence of L. reuteri was shown to reduce the population of Salmonella by diminishing their capacity for adhesion, invasion and intracellular sur
|Contact: Joseph Caspermeyer|
Arizona State University