WASHINGTON (AP) – Scientists have discovered the world’s largest bacterium in a Caribbean mangrove swamp.
Most bacteria are microscopic, but this one is so large that it can be seen with the naked eye.
The thin white thread, about the size of a human eyelash, is “the largest bacterium known to date,” said Jean-Marie Woland, a marine biologist at Lawrence Berkeley National Laboratory and co-author of a paper announcing the discovery. Thursday in the journal Science.
Olivier Gross, co-author and biologist at the University of French West Indies and Guyana, discovered the first example of this bacterium – called Thiomargarita magnifica, or “magnificent sulfur pearl” – attached to sunken mangrove leaves in the 2009 Guadeloupe archipelago.
But he did not immediately realize that it was a bacterium due to its surprisingly large size – these bacteria reach an average length of one third of an inch (0.9 centimeters). Only later genetic analysis revealed that the body was a single bacterial cell.
“It’s an amazing discovery,” said Petra Levin, a microbiologist at the University of Washington in St. Louis who was not involved in the study. “This raises the question of how many of these giant bacteria are there – and reminds us that we should never, ever underestimate bacteria.”
Gross also found the bacterium attached to oyster shells, rocks and glass bottles in the swamp.
Scientists have not yet been able to grow it in laboratory cultures, but researchers say the cell has a structure that is unusual for bacteria. One key difference: It has a large central compartment or vacuole that allows some cellular functions to occur in this controlled environment instead of the entire cell.
“Acquiring this large central vacuole definitely helps the cell get around the physical limitations … of how big the cell can be,” said Manuel Campos, a biologist at the French National Research Center who was not involved in the study. .
The researchers said they weren’t sure why the bacterium was so large, but co-author Woland suggested it could be an adaptation to help it avoid being eaten by smaller organisms.
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The Associated Press’s Department of Health and Science is supported by the Howard Hughes Medical Institute’s Department of Science Education. The AP is solely responsible for all content.
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