Classification• From a common ancestor, 3 domains developed. These include Eukarya, Archaea, and Bacteria. From each of these domains, there are different phylum. The phylum under Eukarya is the Eukaryotes. The phylums under Archaea include Korarchaotes, Euryarchaeotes, Crenarchaeotes, and Nanoarchaeotes. The phylums under domain bacteria include Proteobacteria, Chlamydias, Spirochetes, Cyanobacteria, and Gram- positive bacteria.
• Korarchaeum cryptofilum These archaea have only been found in high temperature hydrothermal environments, particularly hot springs. They have only been found in very small numbers. Research on the gene sequences of these organisms indicates that they are very closely related, although still unique, from Crenarchaeotes and Euryarchaeotes.
• Methanococcus jannischii This is a thermophilic methanogenic archaea, meaning that it thrives at high temperatures and produces methane. This archaea was the first to have its complete genome sequenced. When the genome was sequenced, it became evident that it was very unique and helped with the argument that there are 3 domains instead of 2.
• Sulfolobus solfataricus The origins for DNA replication for this organism were identified in 2004. The results showed that the organism contained 2 origins in its genome. This was the first prokaryote to have evidence of more than one origin for its DNA. Today, it is used to study DNA replication in archaea.
• Nanoarchaeum equitans This organism was discovered in 2002 and is considered a thermophile. It must be in contact with other cells to survive. Scientists still debate whether or not it is a living organism. However, if it proves to be, it would be the smallest living organism on the planet, whose cells have a diameter of 400 nanometers and have a genome of only 490, 885 nucleotides long.
• Escherichia coli This organism is often abbreviated E. Coli. It is a rod shaped bacteria that is found in the lower intestine of warm blooded animals. Although most E. Coli is harmless, certain strands of it can be dangerous and cause food poisoning
• Salmonella enterica This organism is a rod shaped, flagellated bacteria. It is a facultative anaerobe, meaning that it can live with or without oxygen. It is known to infect cattle and poultry, and then when people eat the infected meat, they develop a condition called salmonellosis. Raw eggs can also contain the bacteria, and so this is why people are often cautioned before they consume foods containing raw egg.
• Chlamydia trachomatis This is an obligate intracellular pathogen, meaning that it can grow and reproduce in its host’s cell. It causes complications such as urethritis, proctitis, trachoma, and infertility. Trachoma is a major condition associated with this bacteria, which is an infection of the eye.
• Chlamydia muridarum This was originally considered to be chlamydia trachomatis. However, the difference is that chlamydia trachomatis affects only humans, while chlamydia muridarum affects the family Muridae. This family includes species such as mice and hamsters.
• Borrelia burgdorferi This bacteria mainly exists in North America. However, it has appeared, although more rarely, in Europe. It is the cause of Lyme Disease, which is carried by ticks. Borrelia burgdorferi is one of the few pathogens that can survive without iron. It was the 3rd microbial genome ever sequenced.
• Treponema pallidum This bacteria is associated with the diseases of syphilis, bejel, pinta, and yaws. They are gram- negative, meaning that they have an outer membrane, but cannot be seen on a Gram stained smear because they are too skinny to be seen under a light microscope.
• Prochlorococcus marinus They are the smallest known photosynthetic organisms. In comparing a marine cyanobacteria with eukaryotic algae, the difference in numbers of genes is astounding. While eukaryotic algae has more than 10,000 genes, this species contains only roughly 2,000. It is estimated that 20% of the Earth’s oxygen comes from these creatures. They are also essential to food chains in the ocean.
• Prochloron didemni This is a unicellular photosynthetic organism found mainly in coral reefs. It is theorized in the endosymbiotic theory that these organisms are precursors to the photosynthetic parts of eukaryotes, although this is still highly debated.
• Actinomyces israelii This is known as the “most misdiagnosed disease” because doctors often do not catch it until the later stages. It affects the vagina, colon and mouth. One of the most common diseases associated with the bacteria is Oral- cervicofacial disease, in which the infected person has a lumpy, but painless jaw. Another common disease is thoracic disease, although this is commonly misdiagnosed as a neoplasm.
• Streptomyces achromogenes This bacteria is grown under conditions of 28 degrees Celsius in yeast and malt extract with glucose. It was the original source of a drug intended to help treat pancreatic cancer called, “streptozoticus”
• Streptomyces griseus This bacteria is most commonly found in the soil. It is a well-known producer of antibiotics, and this is the first bacterium to ever produce an antibiotic. It has also been recently discovered as an efficient water purifier.