Washington
Scientists have discovered the world’s largest bacterium in a Caribbean mangrove swamp.
Most bacteria are microscopic, but this one is large enough to be seen with the naked eye.
The thin white filament, the size of a human eyelash, is “the largest bacterium ever known,” said Jean-Marie Woland, a marine biologist at Lawrence Berkeley National Laboratory and co-author of a paper announcing the discovery. In Journal Science.
Co-author and biologist Olivier Gros from the French West Indies and the University of Guyana found the first example of this bacterium, named Thiomargarita magnifa, or “brilliant sulfur pearl”, clinging to submerged mangrove leaves in the archipelago of Guadeloupe. 2009.
But he didn’t know immediately that it was a bacterium because of its surprisingly large size: these bacteria reach an average length of a third of an inch (0.9 cm). Only later did genetic analysis reveal that the organism is a single bacterial cell.
“This is an amazing discovery,” said Petra Levin, a microbiologist at Washington University in St. Louis who was not involved in the study. “It opens up the question of how many of these giant bacteria there are, and reminds us that we should never underestimate bacteria.”
Gross also found bacteria attached to oyster shells, rocks and glass bottles in the swamp.
Scientists are yet to grow it in lab culture, 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 certain cell functions to take place in that controlled environment, rather than the entire cell.
Manuel Campos, a biologist at the French National Center for Scientific Research, said, “The acquisition of this large central vacuole certainly helps a cell circumvent the physical limitations … .
The researchers said they are not sure why the bacterium is so large, but co-author Woland speculates that it may have been an adaptation to help it avoid being eaten by smaller organisms.
