ADVERTISEMENT
2 /3 FREE ARTICLES LEFT THIS MONTH Remaining
Chemistry matters. Join us to get the news you need.

If you have an ACS member number, please enter it here so we can link this account to your membership. (optional)

ACS values your privacy. By submitting your information, you are gaining access to C&EN and subscribing to our weekly newsletter. We use the information you provide to make your reading experience better, and we will never sell your data to third party members.

ENJOY UNLIMITED ACCES TO C&EN

Environment

Metabolites Protect Earthworms Against Harmful Plant Compounds In Diets

Mass spec images show that surfactants called drilodefensins are localized to earthworm gut

by Celia Henry Arnaud
August 11, 2015

GO WITH YOUR GUT
[+]Enlarge
Credit: Manuel Liebeke
In this cross section of an earthworm, mass spec imaging shows that the most abundant drilodefensin is localized in the earthworm’s gut. Levels of the compound are indicated by color, ranging from low (blue) to high (red).
20150811lnp1-gutdrilodefensin.jpg
Credit: Manuel Liebeke
In this cross section of an earthworm, mass spec imaging shows that the most abundant drilodefensin is localized in the earthworm’s gut. Levels of the compound are indicated by color, ranging from low (blue) to high (red).

Earthworms would prefer not to eat a diet high in polyphenols. But they often have no choice. The leaf litter that provides most of their diet is typically high in polyphenols, which can trigger proteins in the worms to precipitate and can disrupt their enzymes. Plants produce these compounds to defend against herbivores.

[+]Enlarge
Credit: Shutterstock
Earthworms digest their high-polyphenol diet with the help of surfactants called drilodefensins.
20150811lnp1-earthworms.jpg
Credit: Shutterstock
Earthworms digest their high-polyphenol diet with the help of surfactants called drilodefensins.

New research suggests that a metabolite unique to earthworms might help them cope with their high-polyphenol diet.

By using mass spectrometric imaging, Jacob G. Bundy of Imperial College London and coworkers showed that a class of metabolites the researchers call drilodefensins are localized in the earthworm gut (Nat. Commun. 2015, DOI: 10.1038/ncomms8869). Worms that eat more polyphenols produce more drilodefensins, according to the researchers.

Chemically speaking, the drilodefensins are dialkylfuransulfonates. They account for about 1% of the worms’ body mass, Bundy says. The researchers have found them in multiple earthworm species but not in other types of worms, such as leeches or aquatic worms, that don’t consume leaf litter. The researchers think the compounds work as biological surfactants that prevent protein precipitation without reducing enzyme activity.

When Bundy and coworkers first identified the compounds, they thought they were probably on the worms’ surface and helping them move through soil. But mass spec imaging revealed that wasn’t the case.

“Not until we got the mass spec images did we realize that, no, they’re in the gut,” Bundy says. “The mass spec imaging completely changed our understanding about their potential function as biological molecules.”

To obtain the images, the researchers needed to freeze the earthworms and cut them into sections. If they tried to extract the gut components, the drilodefensins simply disappeared. Bundy suspects that enzymes toward the back of the worms’ gut rapidly degrade the metabolites to recycle them—especially the sulfur, he says.

Randy A. Dahlgren, a professor of soil science at the University of California, Davis, says the work is of interest because of potential impacts on terrestrial ecosystems. “Polyphenols play an important role in organic matter quality that affects carbon cycling,” he says. “The earthworm turnover of high-polyphenol, organic matter may affect global carbon cycling.”

Advertisement
X

Article:

This article has been sent to the following recipient:

Leave A Comment

*Required to comment