Aquifex
Encyclopedia
Aquifex is a genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 of bacteria
Bacteria
Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...

, one of the few in the phylum Aquificae
Aquificae
The Aquificae phylum is a diverse collection of bacteria that live in harsh environmental settings. They have been found in hot springs, sulfur pools, and thermal ocean vents. Members of the genus Aquifex, for example, are productive in water between 85 to 95 °C. They are the dominant members of...

. The two species generally classified in Aquifex are A. pyrophilus
Aquifex pyrophilus
Aquifex pyrophilus is a rod-shaped bacterium with a length of 2 to 6 micrometers and a diameter of around half a micrometer. It is one of a handful of species in the Aquificae phylum, an unusual group of thermophilic bacteria that are thought to be some of the oldest species in the bacteria domain.A...

and A. aeolicus
Aquifex aeolicus
Aquifex aeolicus is a rod-shaped prokaryote with a length of 2 to 6 micrometers and a diameter of around half a micrometer. It is one of a handful of species in the Aquificae phylum, an unusual group of thermophilic bacteria that are thought to be some of the oldest species of bacteria.A...

. Both are highly thermophilic, growing best in water temperature of 85 °C to 95 °C. They are true bacteria as opposed to the other inhabitants of extreme environments, the Archaea
Archaea
The Archaea are a group of single-celled microorganisms. A single individual or species from this domain is called an archaeon...

.

Both known species of Aquifex are rod-shaped bacteria with a length of 2 to 6 µm
Micrometre
A micrometer , is by definition 1×10-6 of a meter .In plain English, it means one-millionth of a meter . Its unit symbol in the International System of Units is μm...

 and a diameter of around 0.5 µm. They are non-spore
Spore
In biology, a spore is a reproductive structure that is adapted for dispersal and surviving for extended periods of time in unfavorable conditions. Spores form part of the life cycles of many bacteria, plants, algae, fungi and some protozoa. According to scientist Dr...

forming, Gram negative autotrophs. Aquifex means water-maker in Latin, and refers to the fact that its method of respiration
Respiration (physiology)
'In physiology, respiration is defined as the transport of oxygen from the outside air to the cells within tissues, and the transport of carbon dioxide in the opposite direction...

 creates water. Aquifex tend to form cell aggregates composed of up to 100 individual cells.

Aquifex are thermophilic and often grow near underwater volcano
Volcano
2. Bedrock3. Conduit 4. Base5. Sill6. Dike7. Layers of ash emitted by the volcano8. Flank| 9. Layers of lava emitted by the volcano10. Throat11. Parasitic cone12. Lava flow13. Vent14. Crater15...

es or hot spring
Hot spring
A hot spring is a spring that is produced by the emergence of geothermally heated groundwater from the Earth's crust. There are geothermal hot springs in many locations all over the crust of the earth.-Definitions:...

s. A. aeolicus requires oxygen
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...

 to survive, but can grow in levels of oxygen as low as 7.5 ppm. A. pyrophilus can even grow anaerobic
Hypoxia (environmental)
Hypoxia, or oxygen depletion, is a phenomenon that occurs in aquatic environments as dissolved oxygen becomes reduced in concentration to a point where it becomes detrimental to aquatic organisms living in the system...

ally by reducing nitrogen
Nitrogen
Nitrogen is a chemical element that has the symbol N, atomic number of 7 and atomic mass 14.00674 u. Elemental nitrogen is a colorless, odorless, tasteless, and mostly inert diatomic gas at standard conditions, constituting 78.08% by volume of Earth's atmosphere...

 instead of oxygen. Like other thermophilic bacteria, Aquifex has important uses in industrial processes.

The genome
Genome
In modern molecular biology and genetics, the genome is the entirety of an organism's hereditary information. It is encoded either in DNA or, for many types of virus, in RNA. The genome includes both the genes and the non-coding sequences of the DNA/RNA....

 of A. aeolicus has been successfully mapped., This was made easier by the fact that the length of the genome is only about a third of the length of the genome for E. coli. Comparison of the A. aeolicus genome to other organisms showed that around 16% of its genes originated from the Archaea
Archaea
The Archaea are a group of single-celled microorganisms. A single individual or species from this domain is called an archaeon...

 domain. Members of this genus are thought to be some of the earliest members of the eubacteria domain.

A. aeolicus was discovered north of Sicily
Sicily
Sicily is a region of Italy, and is the largest island in the Mediterranean Sea. Along with the surrounding minor islands, it constitutes an autonomous region of Italy, the Regione Autonoma Siciliana Sicily has a rich and unique culture, especially with regard to the arts, music, literature,...

, while A. pyrophilus was first found just north of Iceland
Iceland
Iceland , described as the Republic of Iceland, is a Nordic and European island country in the North Atlantic Ocean, on the Mid-Atlantic Ridge. Iceland also refers to the main island of the country, which contains almost all the population and almost all the land area. The country has a population...

.

External links

  • Aquifex from the Kenyon College biology department's student-edited microbe wiki].
  • The Prokaryotes: An Evolving Electronic Resource for the Mircobiological Community. 2004. Springer-Verlag New York, LLC.
The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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