Worms without mouth or intestines and a unique way of survival

I thought the Mahdi

Tacit relationships between organisms have been known since ancient times, a mutual benefit between the parasite and host that ensures both survival.

An international team of researchers - led by Harald Grufferodica and Oliver Jacquel of the Max Planck Institute for Marine Microbiology in Bremen - decoded the unique symbiotic relationship between the Paracatenula worm and the Riegeria bacteria in which they live. Their findings were published in the journal " (BBS) on April 8.

The worm from the sandy, temperate climate of the Mediterranean Sea is a habitat for it. It has the advantage of having no intestines or intestines. However, it has a distinctive way of coexisting and surviving, with bacteria that provide all its needs.

Journey 500 million years
The flat worm paracetinola lives in the sediments of the warm regions. They can be found all over the world in protected sandy habitats, such as seaweed, coral reefs or mangroves.

Paracetinola's white color is due to its bacterial co-existence, where bacteria and worms have lived in symbiotic relationships for more than 500 million years. During these years, the parasite reduced its genome, maintaining at the same time its basic functions.

Despite this reduction, the bacteria have been able to supply the host worm with everything it needs to survive, employing nearly half the biomass of the worm and filling its main cavity.

"We have not seen anything like this in any other co-existence," said Harald Grubervodica, the lead author of the study. "In spite of this low genome, One bacteria produces a lot of different substances and makes it available to its host. "

As plants use light as a source of energy to produce biomass, bacteria exploit chemical energy in the process of "chemical synthesis" and convert carbon dioxide into organic compounds using energy from hydrogen sulfide, a common compound in the sediments, thus providing fats and proteins, and possibly sugars and acids Fatty and vitamins.

In coexistence
In all known chemical co-existence relationships, the host is digested by bacterial cells to obtain the necessary nutrients to ensure its survival. However, the symbiotic relationship between paracetinola worm and Virgaria bacteria is different.

The team of researchers - when using an electron microscope - that the bacteria of Nigeria provides the worm with many small vesicles that resemble droplets, and scientists compared to the fruit garden, where the bacteria bear fruit continuously and then the worm to harvest those fruits.

The results of the microscopic images showed that the paracetinola worm had no means of secretion, but apparently did not have cellular waste. The worm uses all the bacteria in one way or another.

In addition, the results of the study showed that these worms reproduce abnormally by dividing their bodies, thus increasing the number of worms from those small structural pieces.

The study combines genomics and microbiological and electronic investigations, as well as physiological experiments that allowed the team to investigate this symbiotic relationship from different perspectives. Researchers have been able to keep the worms in laboratory atmosphere for up to three years to this day.