Hello. I'm Jonathan Ewbank.
Researcher. Ciml in Marseille, France.
Today, I'm going to be talking in some detail about the interaction
between C. elegans and a specific fungal pathogen.
Before you watch this lecture,
you may want to see the one that I recorded in 2011,
which gives some background information about C.
elegans and about its interaction with various pathogens.
Organisms throughout evolution have needed active homeostatic mechanisms that
maintain stable internal environment in the face of external variations.
Many of these environmental changes concern abiotic parameters like
ph or temperature that are the same now as they were when life first evolved.
Perhaps, not surprisingly, the molecular mechanisms,
that are deployed, for example,
to counter heat shock, are highly conserved.
Pathogens represent another challenge to organismal homeostasis.
But in this case, the challenge is not static.
Pathogens can evolve rapidly.
As a consequence, post defense mechanisms need to adapt to a constantly evolving threat.
Along each branch of the phylogenetic tree,
species have evolved their own specialized forms of defense.
For example, adaptive immunity is only found in jawed vertebrates.
We have chosen to look at host defenses in the nematode Caenorhabditis elegans,
a widely used model in biology.