Bacteria are small, too small to be seen! But there are no absolutes, and not all bacteria are like this.
According to an article in the journal Science in late February, a "giant bacterium" has been found in the mangroves of Grandetel in the Caribbean Sea, so large that it is visible to the naked eye, and measurements have found that its length can reach two centimeters.
The number of bacteria on the surface of the earth is very large, it can even be said that everywhere, all kinds of objects and the surface and interior of life almost all have bacteria, there are biologists who say that everyone is a carrier of millions of bacteria, that is to say, everyone's body carries millions of bacteria, especially the bacteria in the digestive tract the most, the main species are bifidobacteria and lactobacillus, etc., belong to the probiotic class, so not all bacteria are terrible, some bacteria are even biological survival dependent.
The largest bacteria known to humans before is The Namibian Thiolium, which can reach a maximum diameter of 1 mm, is a sulfur-loving pearl-type fungus, spherical in shape, with a maximum volume of up to 0.5 cubic millimeters, also to the extent that it is visible to the naked eye.
In addition, several bacteria such as Beyler vulcanized bacteria and Fischer's bone fish fungus are basically large enough to be visible to the naked eye. Most bacteria are between 0.5 and 10 microns in length, that is, most bacteria are less than 1% of the length or diameter of one millimeter, which cannot be directly seen by the naked eye.
The discovery of 2 centimeters of bacteria, so that biologists are extremely surprised, because this completely subverts the accepted scientific understanding of how big bacteria may become, previously scientists believe that the size of bacteria is limited by the distance that their molecules can be exchanged with the outside world, so bacteria basically will not be larger than 0.1 mm, otherwise nutrients are difficult to transmit from the cell membrane to the inside, and toxins cannot be transmitted in reverse, so it is difficult for bacteria to survive.
Biologists also believe that this giant bacterium is a new species among bacteria, and suggest that it be named Thiomagarita magnifica (thiomargarita bacterium macros).
This giant bacterium grows on decaying mangrove leaves in Caribbean marshes and appears as a bunch of white filaments. In fact, it was discovered as early as 10 years ago, and its discoverer, Olivier Gross, discovered this white bacterium in this swamp ten years ago, but at that time did not realize that it was a bacterium, but thought it was a fungus, and recently through detailed research and analysis, it was discovered that it turned out to be a giant bacterium.
Many friends may not know the difference between bacteria and fungi, in fact, they are common microorganisms in nature, but usually fungi can grow very large, such as mushrooms, fungus, white fungus, etc., some giant umbrella fungus mushrooms can now grow as large as umbrellas, and some Mabo bacteria grow as large as basketballs.
Giant chicken fir fungus
Giant Marbella
Known to be the world's largest fungus is a strain of Melingella aureus in the Marul National Forest in Oregon, usa, its hyphae cover nearly 10 square kilometers, is considered to be the world's largest organism, the weight of thousands of tons, scientists believe that this fungus has survived for more than 2800 years.
Meldyclus ausces
But the size of bacteria is very small, most of the details mentioned earlier are not directly visible with the naked eye, but their main difference is not in volume, but in composition, bacteria are single-cell prokaryotes, no formed nuclei, there are no chromosomes, the main component of the cell wall is peptidoglycans, cytoplasm is mainly ribosome organelles; and fungi are single-celled or multicellular eukaryotes, there are formed nuclei, the main component of the cell wall is chitin, the cytoplasm in addition to the ribosomes there are endoplasmic reticulum, Golgi, Mitochondria, centrosomes, and other organelles, there are chromosomes in the nucleus, which are formed by the combination of DNA and proteins.
In terms of reproduction, bacteria mainly reproduce by dichotomy, while fungi are mainly budding and spore reproduction.
The biggest feature of the discovery of Thiodia macrophylla is not only its large size, genetic analysis found that its genome is also very large, with about 11 million bases and about 11,000 genes, almost three times the genome of most other bacteria, but many of its genomes are duplicates, researchers found that some sequences have as many as more than 500,000 copies.
The bacterium's tissue structure is also peculiar, its DNA is packed in a membrane sac, which is usually found only in small fungi, so biologists also believe that this giant bacterium may be at an evolutionary boundary between prokaryotes and eukaryotes. Biologists at Kyushu University in Japan believe that the discovery of this huge bacterium "may show a missing link in the evolution of complex cells." ”
Resources:
Global Network February 28 article "Scientists found the largest bacteria so far: longer than a housefly, although it is a single cell but up to 2 centimeters"
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