About This Project

Ask the Scientists

What is the context of this research?

Fresh E. fetida egg capsules, and bacterial isolates from the surface, were tested for their antifungal activity on plates and shown to have an inhibitory effect of certain fungi by 1) a clearing zone around capsules and bacterial colonies (fig. 3), and 2) lack of fungal growth on the cocoons despite being placed directly on a fungal culture. Surveys conducted in my lab have demonstrated that nearly all species in the extensive Lumbricidae earthworm family possess symbiotic bacteria. If these bacterial symbionts produce antifungal substances, there is opportunity to discover novel therapeutics from this highly diverse, unexplored source.

What is the significance of this project?

Earthworms are found all over the world, except Antarctica and very dry deserts. There are many different kinds of earthworms, about 16 described families, that live in various soils, rotting trees, agricultural lands, leaf litter, manure, and river banks.

In my lab I study an earthworm species many people likely have in backyard leaf piles, kitchen scrap vermicomposting bins, or have used for fishing bait. Eisenia fetida, commonly known as red wigglers, grows well in the lab and we have been studying symbiotic bacteria that live in the earthworm nephridia. Nephridia serve as the earthworm’s kidneys, regulating water balance and eliminating waste products. Beneficial bacteria live inside the nephridia and seem to be important for the health of the earthworm, although we don’t know what they are doing yet. We do know that the parent earthworm passes the bacteria from the nephridia into the egg capsules (fig.1 and fig. 2).

What are the goals of the project?

Fresh E. fetida egg capsules, and bacterial isolates from the surface, were tested for their antifungal activity on plates and shown to have an inhibitory effect of certain fungi by 1) a clearing zone around capsules and bacterial colonies (fig. 3), and 2) lack of fungal growth on the cocoons despite being placed directly on a fungal culture. Surveys conducted in my lab have demonstrated that nearly all species in the extensive Lumbricidae earthworm family possess symbiotic bacteria. If these bacterial symbionts produce antifungal substances, there is opportunity to discover novel therapeutics from this highly diverse, unexplored source.