Scientists have discovered the largest bacterium

American scientists have discovered a bacterium with cells a centimeter long, making it the largest of the species of bacteria ever discovered—and even “challenges our understanding of bacterial cells. By comparison, most bacteria are made up of simple cells about two microns in diameter, or about 40 times smaller than a human hair.

A record holder called Thiomargarita magnifica was found on the leaves of a mangrove forest that had gone under water in Guadeloupe. According to researchA centimeter-long bacterium with DNA contained in metabolically active, membrane-bound organelles / Science, published in the journal Science, this species has developed filamentous cells that are about 50 times larger than other bacteria known to science, making them visible to the naked eye.

Scientists suspect that the cells have grown so much thanks to the multiple duplicated genes that T. magnifica - this ability is called polyploidy. Such features point to the increasing complexity of the genus Thiomargarita and challenge traditional ideas about bacterial cells.

First time on T. magnifica came across more than 10 years ago, but for a long time it could not be classified. Although it belongs to a family of predominantly single-celled organisms called prokaryotes, its size and structure are more reminiscent of eukaryotes, which include complex multicellular forms life.

To figure out what it is, biologists used fluorescence, x-rays and electron beams. microscopy, as well as genome sequencing, to reveal new details about the processes inside these huge cells.

It turned out that these bacteria contain DNA clusters that are located in compartments delimited by membranes - scientists called them pepins. This internal organization contrasts sharply with the free-floating DNA in most bacterial cells.

In addition, genetic sequencing has shown that T. magnifica contains hundreds of thousands of copies of its genome scattered throughout the cell, about three times the number of genes in most bacteria. This is probably what helped the organism to grow to an unusually large size and bypass the biophysical and bioenergetic growth limitations.

Identification T. magnifica represents a major milestone for microbiologists, but the study notes that remains many open questions about the life cycle, cellular mechanisms and evolutionary history of this bacterial giant. The researchers also suggest that the very existence of this species hints at the existence of other huge microbes, which could fundamentally change our understanding of life on this scale.