The largest known microorganism in the world: In 1985, Fisherson, Montgomery, and Myrberg discovered the microorganism Epulopiscium fishelsoni in the small intestinal duct of a tropical fish (named surgeonfish) in the Red Sea. It was the largest microorganism found in the world at that time. It looks exactly like a cigar, with a length of about 200~500μm, a longest up to 600μm, and a volume of about 1 million times that of Escherichia coli. This microorganism does not need to be observed by a microscope to be directly detected by the naked eye. The largest microorganism at present is the spherical bacteria found in 1997 by Heidi Schulz in the marine sediments off the coast of Namibia, with a diameter of about 100-750 μm. This is 2 to 4 times larger than the microorganisms mentioned before. In September 2011, Chinese scientists discovered the world’s largest fungal fruit body in Hainan. The fruit body has grown for 20 years. The fruit body has a length of more than 10 meters, a width of close to 1 meter, a thickness of about 5 cm, a volume of 409262–525140 cubic centimeters, and a weight exceeding 500 kg.
The smallest microorganism known in the world that can live independently: Mycoplasma was also translated as "mycoplasma" in the past. It is a type of single-celled microorganism between bacteria and viruses and is known to be able to live independently on earth. The smallest microorganism, about 100 nanometers in size. Mycoplasma is a generally a parasitic organism, the most famous of which is M. Pneumonia, which can cause serious diseases in the respiratory organs of mammals, especially cattle. [2]
Virus: The smallest plant virus, lettuce mosaic virus, is 1.5 nanometers thick and 28 nanometers long; the smallest animal virus, foot-and-mouth disease virus, is only 2.1 nanometers in diameter.
Subvirus: (including virus-like, virus-like, prion) is the smallest microorganism in the world. The size of the virus-like is similar to that of the virus-like; the prion is much smaller than the smallest known conventional virus (about 30~50nm); the virus-like is the smallest known infectious pathogenic factor, and it is simpler than the ordinary virus. The potato spindle tuber disease-like virus, which was first reported in 1971, is only one-39th of the size of the lettuce mosaic virus.