Natures wonders: virus sponge symbiosis (Introduction)

by David Turell , Wednesday, January 29, 2020, 18:57 (1758 days ago) @ David Turell

Viruses help symbiotic bacteria in sponges to survive it appears:

https://www.the-scientist.com/the-literature/viruses-mediate-interactions-between-bacte...

"A newly identified group of viruses may help suppress eukaryotes’ immune response and promote tolerance of endosymbiotic bacteria.

***

"Digging further into the genomic data, the team noticed one group of previously unidentified bacteriophages that were particularly abundant in sponge viromes. To Jahn’s surprise, these phages contained genetic sequences for so-called ankyrin repeats, protein motifs usually studied in bacteria that help pathogenic or commensal microbes infect and manipulate eukaryotic hosts. He wondered if the viruses, which the team dubbed ankyphages, might facilitate interactions between sponges and their resident bacteria.

"Both sponge cells and their endosymbiotic bacteria are difficult to culture, so to test Jahn’s idea, the team set up an experiment with mouse cell lines and E. coli. The researchers first cultured E. coli with ankyrin protein synthesized from the viral sequences. Then they added the bacteria, which displayed the protein on their cell surfaces, to murine immune cells.

"Sure enough, the E. coli that had been cultured with ankyrin protein were better at surviving exposure to mouse immune cells: they escaped being engulfed by macrophages more often than control bacteria did. E. coli engineered to produce and secrete the phage proteins themselves also survived macrophage exposure. The team ran further experiments to confirm that the protein wasn’t toxic to either the bacterial or murine cells, and concluded that phage-derived ankyrin was indeed helping to suppress macrophage responses toward the bacteria.

***

"Scanning genome databases for other phyla, Jahn and his colleagues found evidence that ankyphages are also present in the microbiomes of other eukaryotic organisms, including humans. The findings hint at the importance of bacteriophages in eukaryotic function, says Jahn. Far from being incidental stowaways in eukaryotic organisms, phages “are central elements,” he says. “It opens a lot of perspective for further research.'”

Comment: The bush of life has many interlocking helpful arrangements, such as the human microbiome. Now more evidence of a helpful virome. This adds to our recognition of the importance of interlocked econiches which are just as helpful in supporting all of life. All of living organisms have a degree of dependence upon all other organisms. Not all viruses are dangerous like the new Chinese Corona virus. The competition which is a large part of the Darwin theory is only a small part of the story. Viruses, which are only partially alive in the sense they must be part of fully independent living forms, play a major role in life and perhaps in driving evolution, as previously proposed. Looks like they were created for a major set of purposes.