First discovery! What is special about bacteria that are visible to the naked eye, which is 5,000 times larger than ordinary microorganisms

What are microorganisms? The main reason why microorganisms are called microorganisms is that our naked eye is difficult to catch, and their existence can only be found through microscopes, they are tiny organisms that cannot be observed by the naked eye, such as bacteria, viruses, fungi, etc. we call microorganisms.

Recently, a very strange thing, scientists have found a strange bacterium in the Caribbean mangrove forest, its linear single cells that we can see with the naked eye, are 2 centimeters long, 5,000 times more than other microorganisms. In addition to being large, what makes this organism very special is that its genome is very complex. Generally speaking, the genetic information of bacteria is free floating in the cell, but the newly discovered single-celled organism has two membrane sacs, and its genetic information is contained in one of the membranes, which is very different from the bacteria we have known in the past. This more complex feature is actually more in favor of the body's cells.

The single-celled organism is so big that scientists believe the discovery raises the upper limit of what humans think is the size of bacteria by a factor of 10.

Prokaryotes and eukaryotes

All along, scientists have simply divided life into two categories, prokaryotes and eukaryotes.

Prokaryotes are actually bacteria in a broad sense, the nuclei of such organisms are not wrapped in nuclear membranes, their DNA is exposed, we say bacteria, cyanobacteria, archaea are one of the prokaryotes with very simple structure, their body size is also very small, generally in the general 1 ~ 10 μm.

Eukaryotes, on the other hand, are much more complex. The biggest difference from prokaryotes is that it has a nuclear membrane as the boundary of the nucleus inside its cells, and the coverage of eukaryotes from protists to fungi, plants, and animals is quite extensive. In addition, eukaryotes tend to have more organelles than prokaryotes.

Neither

As a result, the single-celled organisms that scientists found in the Caribbean mangroves can neither be called prokaryotes nor eukaryotes.

In fact, the organism discovered this time is the only bacteria currently discovered by humans to clearly separate the genetic material in membrane-bound organelles in a eukaryotical manner. That is, the organism is essentially somewhere between prokaryotes and eukaryotes.

This peculiar single-celled organism has two membrane sacs, and its DNA material is contained in one of the membrane sacs, rather than being exposed and floating freely in the cell like other prokaryotes; its other sac is filled with water, accounting for 73% of the total volume, which can help the contents of the cell to cling to the outer cell wall and facilitate the entry and exit of molecules. Scientists believe that this water-filled sac is likely to be the main reason why the bacterium is so large

Scientists continued to sequence the DNA of the single-celled complex organism and found that its genome was very large, containing 11 million bases, including 11,000 genes that could be clearly distinguished. The number of genes is arguably far greater than that of other bacteria, whose genomes average only 4 million bases and 3900 genes.

By labeling the organism's DNA with fluorescent tags, the scientists found that there were more than 500,000 copies of the same DNA fragment, with ribosomals located inside the DNA sac, suggesting that the organism was more efficient at converting genetic code into proteins. This means that this organism achieves a more complex structure and control than other bacteria.

Discoveries of strange creatures

The creature was discovered about 10 years ago by Olivier Gros, a marine biologist at the University of the French Antilles (Pointe-à-Pitre), on the surface of decaying mangrove leaves in the local marshlands. The creature looked as long as a filament, and at first the biologist thought it was an ordinary creature, after all, it was here. Unexpectedly, after 5 years, the research team discovered that these organisms are actually bacteria.

Two centimeters in size, bigger than an ant. It's hard to think at first that they're microbes.

One of the things that people have been criticizing evolution for a long time is that we haven't found the intermediate form of species evolution. Perhaps the discovery of the Caribbean mangroves can give us some new inspiration. There may really be intermediate forms of certain species on Earth.

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