It is understood by most scientists and especially biologists and microbiologists that micro-organisms are ubiquitous by nature, meaning they can be found almost anywhere in almost any environment including some very extreme and severe conditions. These bacteria and Archaea are referred to as extremophiles. You can get halophiles like your Streptococci that live in extremely salty conditions, thermophiles like Cyanidium caldarium that like in conditions above 60°C and many, many, more. In this report, I would like to focus specifically on barophiles, bacteria and Archaea that live in conditions with extremely high pressures, for instance: at the bottom of the ocean, thousands of meters below the surface where humans would be crushed by the weight of the water.
In 1997, a particular study was performed where and unmanned craft was sent to the deepest part of the ocean, the Marianas Trench, where it took a sediment sample and brought it back for analysis. From this sediment sample they extracted several bits of DNA which coded for prokaryotic ribosomal RNA. This RNA held genes that coded for pressure regulation within the cell. This prevents the bacteria from bursting and dying. This DNA was identified to be very closely related to the genus Pseudomonas, one of the most wide spread genera in the world.
A lot of people believe that Archaea are better adapted to living in extreme environments than bacteria and to an extent they are as they have an ether bond opposed to an ester bond in their phospholipid bilayer membrane which surrounds the cell. This ether linkage is chemically far more resistant than the ester linkage, allowing the archaeon to be far more resistant to extreme acidic or alkali environments and high temperatures and so on. However, in this sample of sediment from the Marianas Trench, the DNA of Pseudomonas, a genus of bacteria, was found along with other marine Archaea DNA: so even though Archaea are better adapted to chemically extreme...
References: • Lecture notes
• Chiaki Kato, Lina Li, Jin Tamaoka, Koki Horikoshi. 1997. Molecular analyses of the sediment of the 11000-m deep Mariana Trench. Extremophiles. 1:117-123.
• Koki Horikoshi. 1998. Barophiles: deep-sea microorganisms adapted to an extreme environment. Current Opinion in Microbiology. 1:291-295
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