Thiomargarita magnifica – in reference to its exceptional size – has an average cell length of over 9,000 μm, roughly 1 cm (0.4 in) in length. The cells of most bacteria are about 2 µm in length, although larger cells can be as large as 750 µm.
T. magnifica can be up to 2 centimeters long, according to study co-author Jean-Marie Foland, a marine biologist and scientist at the California Laboratory for Complex Systems Research, and a member of the US Department of Energy’s Joint Genome Institute.
“To understand how big this is for bacteria, it’s as if we found a human the length of Mount Everest,” he told CNN on Wednesday.
More than 625,000 E. coli bacteria can fit on the surface of a single T. magnifica. However, despite the bacteria’s size, their surface is “remarkably pure,” free of surface-dwelling bacteria on living plants and animals, according to the study.
How do you maintain its size?
It was previously believed that bacteria cannot grow to the size visible to the naked eye due to how they interact with their environment and produce energy.
Unlike most bacteria, which contain genetic material freely floating within their single cell, T. magnifica cell contains its own DNA contained in small membrane-bound sacs called pepins.
“This was a very interesting discovery that opened up a lot of new questions because it’s not something that is classically observed in bacteria. It’s actually a feature of more complex cells, the type of cells that make up our bodies or our animals and plants,” Foland said. “We want to understand what those epitopes are and what exactly they do, and whether they play a role in the development of gigantism for these bacteria, for example.”
T. magnifica was first discovered growing as thin white threads on the surfaces of decomposing mangrove leaves in shallow tropical marine mangrove swamps in Guadeloupe, according to the study.
These giant bacteria grow on sediments at the bottom of sulfur waters, where they harness the chemical energy of sulfur and use oxygen from the surrounding water to produce sugars, according to Voland. T. magnifica can also make food from carbon dioxide.
It has been suggested that by being much larger than the average bacteria, a T. magnifica cell could be better at accessing both oxygen and sulfur in its environment at the same time, according to Voland.
It’s also possible that the size of T. magnifica’s cells compared to other microbes in the bacterial group means they don’t have to worry about being eaten by predators.
Microbial black box
Tania Woicki, chief scientist at Lawrence Berkeley National Laboratory in California, thinks giant bacteria, or related species, are likely to be found in other mangroves around the world.
“It always amazes me how little we know about the microbial world and how much is out there,” she told CNN Wednesday, adding that the microbial world is “still a black box.” Wiki, who leads the US Department of Energy’s Joint Genome Institute’s Microbial Genomics Program, is a senior author on the study.
The study concluded that “confirmation bias related to virus size has prevented the discovery of giant viruses for more than a century.” “The discovery of Ca. T. magnifica suggests that large, complex bacteria may be hiding in plain sight.”
“Just because we haven’t seen it yet, doesn’t mean it doesn’t exist,” Wiki added.
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