Scientists discover the world's largest bacterium in mangrove swamp

Scientists discover the world's largest bacterium in mangrove swamp

Scientists have discovered the world's largest bacterium in a mangrove swamp.

Most of the bacteria are microscopic, but this one is so big that it can be seen with the naked eye.

Jean-Marie Volland, a marine biologist at the Lawrence Berkeley National Laboratory and co-author of a paper announcing the discovery Thursday, said that the thin white filament, approximately the size of a human eyelash, is the largest bacterium known to date.

Olivier Gros, a co-author and biologist at the University of the French West Indies and Guiana, found the first example of this bacterium — named Thiomargarita magnifica, or magnificent sulfur pearl — clinging to sunken mangrove leaves in the Archipelago of Guadeloupe in 2009.

He didn't immediately know it was a bacterium because of its surprisingly large size, just over a third of an inch 0.9 centimeters long. Only later, genetic analysis revealed the organism to be a single bacterial cell.

It 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 are out there and reminds us that we should never underestimate bacteria. Gros found the bacterium attached to oyster shells, rocks and glass bottles in the swamp.

The researchers say that the cell has a structure that is unusual for bacteria, and that scientists have not yet been able to grow it in lab culture. One key difference is that it has a large central compartment, or vacuole, that allows some cell functions to happen in that controlled environment instead of throughout the cell.

Manuel Campos, a biologist at the French National Center for Scientific Research, said that the acquisition of this large central vacuole helps a cell to bypass physical limitations on how big a cell can be.

The researchers said they'ren't certain why the bacterium is so large, but co-author Volland hypothesized it may be an adaptation to help it avoid being eaten by smaller organisms.