Discover the world’s largest bacteria in Guadeloupe

It has the shape of an eyelash and turns microbiology knowledge upside down, Olivier Gros, professor of biology at the University of the Antilles and co-author of the study, explained to AFP.

According to this, bacteria can be “seen with the naked eye” and even “grabbed with tweezers”. The researcher first discovered the species in 2009 in mangrove forests in the French overseas territories of the Caribbean. “At first I thought it was just bacteria. Because something two centimeters high cannot be bacteria,” Gross said. However, with the help of an electron microscope, it soon turned out to be a bacterial organism.

A colleague of Gros found that it belongs to the family Thiomargarita, a previously known genus of sulfur bacteria that use sulfides to grow. Gross explained that additional findings by a scientist at the CNRS Research Center in Paris indicated that it was a “single cell”.

The first attempt to publish in a scientific journal was canceled for lack of convincing photographic evidence. Only young researcher Jean-Marie Voland at the University of California, with financial support and 3D microscopes, was able to produce a convincing representation of the giant bacteria. In terms of human dimensions, Foland said the new discovery is as huge for its peers as “if a human was ever going to meet someone the size of Mount Everest”.

He made another interesting discovery: Normally, the DNA of bacteria floats freely in the cell. However, in the newly discovered species, they are encapsulated in small membrane-enclosed structures, he explained. This is “usually characteristic of human, animal and plant cells and complex organisms (…) but not of bacteria”.

The researchers now want to know if this type of DNA is only found in Thiomargarita magnifica or whether it can also be found in other types of bacteria.