The World’s Largest Bacterium was discovered in a Caribbean Mangrove swamp by scientists. This threadlike single-celled organism seems to grow up to 2 centimeters and is 5000 times bigger than any other microbes.
Normally, bacteria are supposed to be microscopic and composed of isolated cells or colonies. Instead, this newly discovered sulfur-oxidizing bacteria was found to have an unexpectedly complex cell. It has a huge genome that wasn’t floating freely inside the cell like other bacteria and instead was encased in a membrane. This was an interesting discovery as it was a characteristic observed in much more complex cells, like those found in the human body.
For the longest time, science has taught us that life is divided into 2 groups – prokaryotes including bacteria and single-cell microbes or organisms lacking a nucleus, and other organelles, and eukaryotes which are organisms whose cells have a nucleus enclosed within a nuclear envelope, ranging from yeast to multicellular life. Another distinction is that prokaryotes have free-floating DNA and eukaryotes package their DNA in a nucleus. But the discovery of this large bacterium has undeniably hazed the borders between prokaryotes and eukaryotes, thereby qualifying the bacterium as a subject to be vastly researched on for further discoveries.
In addition to this, the cell was found to have two membrane sacs, one of which contains all the cell’s DNA and the second being a water-filled sac, which is suspected to be the reason why the bacterium could grow so big. The huge sac – presumably of water – takes up 73% of its total volume. This certain property gives enough incentive for researchers to compare it with a giant sulfur-eating microbe once discovered on the coast of Namibia, in 1999. The reason behind its large size could be because its cellular contents are squished up against its outer cell wall by a giant water and nitrate-filled sac. These similarities and genetic analysis led to the research team placing the bacterium in the same genus as most microbial giants and proposed the name Thiomargarita magnifica.
“All too often, bacteria are thought of as small, simple, ‘unevolved’ life forms – so-called ‘bags of proteins'”, says Chris Greening, a microbiologist at Monash University, Clayton. Greening adds, “But this bacterium shows this couldn’t be much further from the truth.”