Balance of nature: symbiosis (Introduction)

by David Turell , Tuesday, January 14, 2025, 21:20 (8 days ago) @ David Turell

Bacteria help Arctic worms:

https://www.the-scientist.com/bacteria-help-worms-brave-the-harsh-antarctic-cold-72434?...

"While researchers had identified that some Antarctic marine animals make antifreeze proteins to adapt to the extreme cold, similar mechanisms in invertebrates remained poorly understood.1

"In a study published in Science Advances, Corinaldesi and colleagues have shown that the microbiome of Antarctic worms produces cryoprotective proteins that help these creatures cope with freezing temperatures.2 The results provide insights into how the microbiome can help the host adapt to extreme environmental conditions.

"Analyzing the sequences revealed that bacteria belonging to the genera Meiothermus and Anoxybacillus made up most of the worms’ microbiome. Although scientists have found these species in frigid environments before, they are most commonly seen in high temperatures, such as hot springs.

"The microbiome’s role in providing nutrition or immunity is well-established, said Har­ald Gruber-Vodicka, a marine symbiosis researcher at Max Planck Institute for Marine Microbiology, who was not involved with the study. “But cold protection as a symbiont service or a symbiont function was surprising and new.”

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"The researchers found that these bacteria were not present in any other worm species whose metagenomes were available in gene banks. They also did not find these bacteria in the sediment where they collected the worms, indicating that the worms did not recently acquire these bacteria from their environment.

"This led the team to investigate whether the worm-microbe connection started in the past and was passed down through the generations. They studied the relationship between the evolutionary history of the host—assessed by analyzing its mitochondrial genes—and that of the microbiome associated with the host. This revealed a high degree of phylosymbiosis, or similarity, suggesting that the microbes and the worms may have coevolved.

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“'The symbiosis started in ancient times, probably when the habitat was different, and now these bacteria are no longer present in the surrounding sediments of the animals,” said Corinaldesi.

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"When they analyzed worm extracts using a proteomics approach, they found many of these proteins and several enzymes that are potentially useful for coping with extreme cold temperatures. Matching these proteins with established databases that describe protein sequences and their functions helped the team pinpoint that the bacteria, and not the worms, produced several of the cryoprotective proteins.

"The fact that the microbiome produced specific proteins that can help the host cope with the cold was surprising, said Corinaldesi."

Comment: my guess is these guys coevolved from a time when the Arctic was warm