Figure 1: Host survival showing protective effects of E.
faecalis . Early exposure of worms toE. faecalis (both ancestors) provides some degree of protection
from the infection of S. aureus . 24h host survival levels reveal
a benefit to E. faecalis colonisation independent of pathogen
presence or absence. Circles indicate those treatment being exposed toE. faecalis and food in the earlier stage (L1-L4), while squares
indicate food alone treatment in the earlier stage (L1-L4). Filled
symbols indicate those treatments being exposed to food in the later
stage, while open symbols indicate those treatments being exposed to the
pathogen S. aureus in the later stage. Each symbol indicates the
mean ± S.E of five replicates. Axis scales were chosen to be the same
across all plots.
Before the start of the evolution experiment, the starting conditions
were tested. Confirming previous results, E. faecalis showed some
spontaneous host-protective potential against S. aureus . Worms
raised on E. faecalis and food survived better than those raised
on food alone, independent of food or pathogen present at the later
stage (General Linear Model, X2=10.205, df=1, p=0.001;
Figure 1). Worms infected with S. aureus in later life survived
worse than those being exposed to food (General Linear Model,
X2=119.643, df=1, p<0.001; Figure 1). These
results demonstrate the beneficial and protective effects for the host
after exposure to the protective microbe E. faecalis .