肉眼で見える - Living, Loving, Thinking, Again

Hannah Devlin “Scientists discover world’s largest bacterium, the size of an eyelash” https://www.theguardian.com/science/2022/jun/23/scientists-discover-world-largest-bacterium-thiomargarita-magnifica-bacteria

カリブ海の仏蘭西領グアドループ *1のマングローブで、「人間の睫毛のサイズ」があり、肉眼でも見える「世界最大の細菌」が発見された。

At about 1cm long, the strange organism, Thiomargarita magnifica, is roughly 50 times larger than all other known giant bacteria and the first to be visible with the naked eye. The thin white strands were discovered on the surfaces of decaying mangrove leaves in shallow tropical marine marshes.
The discovery was a surprise because, according to models of cell metabolism, bacteria should simply not grow this big. Previously scientists had suggested an upper possible size limit about 100 times smaller than the new species.

The organism was discovered by Olivier Gros*2, a marine biology professor at the Université des Antilles in Guadeloupe, while searching for symbiotic bacteria in the mangrove ecosystem.
“When I saw them, I thought: strange,” said Gros. The lab first conducted microscopic analyses to establish that the strands were single cells. Closer inspection also revealed a strange internal structure. In most bacteria, the DNA floats around freely inside the cell. Thiomargarita magnifica appears to keep its DNA more organised inside membrane-bound compartments throughout the cell. “And this is very unexpected for a bacterium,” said Volland.
The bacterium was also found to contain three times as many genes as most bacteria and hundreds of thousands of genome copies spread throughout each cell, making it unusually complex.

共同研究者のJean-Marie Vollandさん*3は人間でいうと、身長がエヴェレストと同じということだという。

Ca. Thiomargarita magnifica is therefore a fascinating example of a bacterium that has evolved a higher level of complexity. https://t.co/JEt5FrQWXq
— Jean-Marie Volland (@JeanVolland) 2022年6月23日

We’ve got news! Have you heard? “Giant Bacteria Found in Guadeloupe Mangroves Challenge Traditional Concepts”@BerkeleyLab @twoyke @silvinagrizzo @jgi @LBNLBioSci @lrcsystems @UnivAntilles @ScienceMagazine
https://t.co/hhi86Kuxo8
— Jean-Marie Volland (@JeanVolland) 2022年6月23日