Researchers have developed and analyzed the genes of the glowing bacteria that live in the light bulb hanging over the anglerfish head.

The anglerfish lived most of its life in full darkness, over 1,000 meters below the ocean surface. Female fish sport a glowing lure on top of their foreheads, with the pole having a light bulb at the end, a place for living of the bioluminescent bacteria. Lighting comfort attracts both the fish and its potential friends.

Researchers of bacteria are less aware of the fish and their interactions with these amazing bacteria because fish are hard to get and learn. This new study came from fish samples collected in the Gulf of Mexico.

Researchers report their findings in the mBio journal. Analysis has shown that bacteria have lost some of the genes needed to live freely in the water. This is due to the fact that fish and bacteria develop a close beneficial relationship, Generating of light depends on bacteria, while nutrients provided by the fish to the microbe.

“What is particularly interesting about this particular example is that we see evidence that this evolution is still in progress, although the fish has evolved about 100 million years ago,” said lead author Tory Hendry, assistant professor of microbiology at the University of Cornell. “Bacteria still losing genes, and it is not clear why.”

“… This is the third type of situation where the bacteria are not stuck to their real host, but they are in the process of evolution.”

Bacteria in the bulb of anglerfish represents a third type of symbiosis, where data show that these primary bacteria can be changed from the bulb of anglerfish to the water. “It’s a new understanding of symbiosis, where the bacteria are not stuck to their host, but they are in the process of evolution,” Hendry said.

The genetic sequence shows that the genes of these anglerfish bacteria are 50% less than their relatives. Most bacteria have lost genes associated with the production of amino acids and breaking down nutrient other than glucose, which suggests that fish can supply bacteria with nutrients and amino acids.

In the meantime, bacteria keep some of the genes useful in water outside the host. They have a full path to creating a flagellum, a tail of corkscrew to move in the water. Bacteria have lost genes involved in detecting chemical signals in an environment that may lead to food or other useful ingredients, although some still leave a set of chemicals they still respond to.

“They have been reduced to what they are interested in,” Hundy said.

The Gulf of Mexico Research Initiative funded the study.

Source: Cornell University

Early Study DOI: 10,1128 / mBio.01033-18

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