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Old 25-06-2022, 10:35 AM
gary
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Largest-known bacterium found in mangrove — and you can see it without a microscope

25 June 2022. ABC News reports on the discovery of a bacteria so large it can be seen naked eye, found in a mangrove swamp in the forests of Guadeloupe. It has been named T. magnifica.

Quote:
Originally Posted by ABC Science / By science reporter Gemma Conroy
They have tiny seed-like compartments containing the bacterium's genetic blueprint.

These "pepins" were a bizarre feature, because bacterial DNA typically floats freely inside cells instead of being neatly bundled inside cellular containers as it is in humans, plants and animals.

"This has never been observed in bacteria before," the discover, Dr Volland said.

"It is actually something that is characteristic of complex organisms."
The team sequenced T. magnifica's genome using five of the filaments they collected.

The genome itself was huge and contained roughly 12,000 genes — that's three to four times more than most bacteria, Dr Volland said.
A large portion of the giant bacterium's genes also indicated that it stores carbon and relies on sulphur for energy.

The bacterium also contains about 37,000 copies of its genome per millimetre, the largest number of copies to be found so far in a bacterial cell.

Professor Franks said the wealth of genetic material in T.magnifica offered a tantalising new toolbox for designing and engineering organisms to create products like biofuels, pharmaceuticals and food.
"I always think of a genome like a book, and this is a massive library of 37,000 copies of the book, and you can have different books for different things," he said.

"You could hold a whole bunch of different copies of information in different genomes and get them to switch on and off, depending on what you need."
The discovery has been reported in Science.
Quote:
Originally Posted by "A centimeter-long bacterium with DNA contained in metabolically active, membrane-bound organelles", Jean-Maie Volland, et. al. Science
Abstract
Cells of most bacterial species are around 2 micrometers in length, with some of the largest specimens reaching 750 micrometers. Using fluorescence, x-ray, and electron microscopy in conjunction with genome sequencing, we characterized Candidatus (Ca.) Thiomargarita magnifica, a bacterium that has an average cell length greater than 9000 micrometers and is visible to the naked eye. These cells grow orders of magnitude over theoretical limits for bacterial cell size, display unprecedented polyploidy of more than half a million copies of a very large genome, and undergo a dimorphic life cycle with asymmetric segregation of chromosomes into daughter cells. These features, along with compartmentalization of genomic material and ribosomes in translationally active organelles bound by bioenergetic membranes, indicate gain of complexity in the Thiomargarita lineage and challenge traditional concepts of bacterial cells.
Full story, images here :-
https://www.abc.net.au/news/science/...wamp/101170176
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