The Most: Related to Microbes

PPLO

1.         Largest (longest) plant virus	Citrus tristeza (rod shaped)- 20,000 nm in size (0.02 mm)
2.         Largest animal virus	Parrot fever Virus (450 µ)
3.         Largest bacterium	Bacillus butschli (800mm). Spirillum volutans (13-15 mm in length)
4.         Largest forms of bacteria	Spiral. Up to 500 mm
5.         Largest protozoan (Largest amoeba)	Pelomyxa palustris (giant amoeba) about 2 mm
6.         Largest species of bacterium ever discovered	Thiomargarita namibiensis, which grows to 0.75 mm (0.03 in) in diameter, making it visible to the naked eye and up to a million times the size of more typical bacteria
7.         Largest sulphur bacterium	Thiophysa volutans (18 mm)
8.         Largest virus	TMV (300 nm), Pox virus (280 nm)
9.         Largest virus	Mimivirus (the Acanthamoeba polyphaga mimivirus), with mature particles of 400 nm in diameter (icosahedral capsid), 800,000 bases and 900 genes. Later research suggested that it could be up to 800 nm long, 1.2 Mbp and 1,260 genes
10.       Oldest microbe	Bacillus form of bacteria. 250 million years old.
11.       Smallest animal virus	Foot and Mouth virus (10 nm size), Polio virus (27 nm in diameter)
12.       Smallest bacterium	Dialister pneumosintes (0.15-0.3 mm in length). In nasopharynx of man.
13.       Smallest DNA bacteriophage	Phi-X174 phage, thought to be larger than Hepatitis B, at about 4 kb. It is important to consider other self replicating genetic elements such as satelliviruses and Viroids.
14.       Smallest DNA viruses	Hepadnaviruses such as Hepatitis B, at 3.2 kb and 42 nm; parvoviruses have smaller capsids, at 18-26 nm, but larger genomes, at 5 kb.
15.       Smallest infectious material	Prion (100 to 1000 times smaller than tobacco necrosis virus)
16.       Smallest known plant virus	Satellite tobacco necrosis virus (Alfalfa mosaic virus; 17 nm in diameter)
17.       Smallest organism	PPLO (Pleuro Pneumonia-like Organism) or Mycoplasma genitalium (200 to 300 nm in size)
18.       Smallest RNA viruses in terms of genome size	Retroviruses such as rous sarcoma virus with genomes of 3.5 kb and particle diameters of 80 nm
19.       Smallest self replicating organism	Mycoplasma
20.       Smallest virus	Virus of foot & mouth disease (20 nm)

TMV