# video | These worms are without a mouth and digestive system feed in the most unexpected way.
Every living organism needs food intake, but there are creatures in the world that do not have either a mouth or a digestive system. For example, these include flatworm parakatenuly that live on the seabed in regions with a temperate climate. Without the ability to directly consume nutrients, these creatures manage to live peacefully for 500 million years. And their secret is that inside them is full of Riegeria bacteria, which release the organic compounds necessary for life.
Bacteria live in the organs of worms, called trophosomes, and fill almost the entire cavity of their bodies. The worms themselves are transparent, but it is these organs with bacteria that give them a white color. Bacteria are chemosynthetic, that is, they use chemical reactions, not solar color, to generate energy. In particular, we are talking about the reaction of carbon dioxide and hydrogen sulfide, which synthesizes lipids, proteins, sugars, fatty acids and vitamins.
Over the past millennia, the Riegeria bacteria have so simplified their genome that now they perform only the most important functions. Marine microbiologist Harald Gruber-Vodicka shared that they had never seen such a symbiosis, when a bacterium with such a simplified genome produces so many nutrients.
Usually, with such symbiosis, the host practically digests the bacteria inside it. However, this is not the case – microorganisms independently secrete substances necessary for the organism in the form of tiny droplets. Because of this, they always remain unharmed, and this symbiosis can be considered ideal and advantageous for both flatworms and microbes.
Concerning worms there is another interesting material – recently a group of researchers from the University of Michigan discovered that roundworms have a substance that prevents aging.
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