By using the latest techniques in spectroscopy, the molecular analysis of the digestive tract fluid of earthworms has revealed the secret to how they actually digest plant toxins.
Scientists say the slimy creatures produce special compounds in their digestive system to neutralize the toxins in plants, that are normally released to repel herbivores.
Earthworms can chew through leaves and dead roots that are otherwise toxic to herbivores but how they manage to do it was a mystery until recently.
This Tuesday, a team of researchers that worms produce special compounds in their gut to counteract toxins eliminated by plants to drive back other plant-eaters.
The study presented in the journal Nature Communications explained that earthworms, the creatures which burrow into and help enrich and aerate soil, possessed a class of unique-surface metabolites in their gut, termed “drilodefensins”. This means that this was the earthworm’s secret weapon.
The chemicals produced by plants, known as polyphenols, which offer plants their color and serve as antioxidants, also act as a shield by suppressing digestion in a wide variety of herbivores. The polyphenols are, otherwise, beneficial to humans. About the negative effects they have on herbivores – they inhibit digestion by preventing enzymatic processes.
Earthworms are the small creatures that eat fallen leaves and other materials produced by plants, returning to the soil the carbon kept in the waste. Statistics show that earthworms turn over 35 billion tons of leaf litter and dead grass every year.
The real question was how they actually tolerated polyphenols, the colorful phyto-chemicals found in plants. The scientists used mass-spectroscopy visualization techniques to identify the essential element to the earthworms’ digestive systems.
Jake Bundy and Manuel Liebeke, from Imperial College London, leaders of the research team, discovered the drilodefensins in the digestive systems of 14 earthworm species, but not in other relatives of the earthworm – such as leeches and sewage worms. Thus, these molecules are specific only to earthworms.
Dr. Dave Spurgeon, co-author of the study, said that worms have a “metabolic coping mechanism” to counter plant toxins.
They made a statement which reported that for every person on Earth there would be at least one kilogram of drilodefensins present within the earthworms that populated the world’s soils.
Bundy continued by saying that fallen leaves would remain on the surface of the ground for a significant amount of time, creating a thick layer, if it weren’t for drilodefensins. He concluded with the fact that rural areas would be unrecognizable and the carbon cycle would be disrupted.
The compound’s name was derived from the Latin name of invertebrates including earthworms: Megadrile.
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