The largest bacterium discovered is visible to the naked eye

by mcdix

When you hear the word “bacteria,” you probably imagine organisms you cannot see unless placed under a microscope. However, a bacterium now classified as the largest in the world ever discovered does not require any special tools to be visible to the naked eye. Thiomargarita magnifica, as it is called, takes on a filament-like appearance and can be as long as a human eyelash. As the BBC points out, this makes it larger than some more complex organisms, such as tiny flies, mites, and worms. It was first discovered by marine biologist Olivier Gros who lived on submerged mangrove leaves in the French Caribbean in 2009.

Because of the organism’s size, Gros first thought he was looking at a eukaryote rather than simpler prokaryotic organisms like bacteria. It wasn’t until he returned to his lab that he discovered that wasn’t the case. Years later, Jean-Marie Volland and his team at Lawrence Berkeley National Laboratory in California took a closer look at the bacterium using various techniques, such as transmission electron microscopy, to confirm that it is indeed a single-celled organism. They recently published a paper describing the centimeter-long bacterium in Science.


Volland said T. magnifica is “5,000 times larger than most bacteria” and is comparable to an average person “meeting another human the size of Mount Everest.” Another piece of information Volland’s team has discovered is that the bacterium keeps its DNA organized in a structure with a membrane. In most bacteria, DNA materials float freely in their cytoplasm. Furthermore, it has about 6,000 billion bases of DNA. “By comparison, a diploid human genome is about six giga (billion) bases in size. This means that our Thiomargarita stores several orders of magnitude more DNA than a human cell,” says team member Tanja Woyke.

Although scientists know that T. magnifica grows atop mangrove sediments in the Caribbean and creates energy for life using chemosynthesis, similar to photosynthesis in plants, much remains a mystery. And it will probably be some time before the scientists can uncover the secrets: They have yet to figure out how to grow the organism in the lab, so Gros must collect samples whenever they want to run an experiment. It doesn’t help that the organism has an unpredictable life cycle. Gros told The New York Times that he couldn’t find one for the past two months.

Volland and his team now want to find a way to grow T. magnifica in the lab. As for Gros, he now expects other groups to look for even larger bacteria, which, like T. magnifica, can also hide in plain sight. Our editorial team, independent of our parent company, has selected all products recommended. Engadget recommends our stories contain affiliate links. We may earn an affiliate commission if you buy something through one of these links.

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