Pyrococcus "fireball" furiosus
A Microbial Biorealm page on the genus Pyrococcus "fireball" furiosus
Classification
Archaea; Euryarchaeota; Thermococci; Thermococcales; thermococcaceae; pyrococcus; P. furiosus
Description and significance
Discovered by Karl Stetter in 1986 off the coast of Italy, P. furiosus is an aquatic, hyperthermophilic Archaea that grows at extremely temperatures in the range of 70 °C to 103 °C, at and around the boiling point of water (1). It’s name Pyrococcus means “fireball” in Latin, referring to the organism’s round shape and ability to live in temperatures unbearable to most other organisms. Out of all the Archaea, it has the shortest generation time of only 37 minutes. It is one of the few organisms that contains the element tungsten. It is interesting that the organism contains this element since tungsten has the highest melting point of all the non-alloyed metals and the second highest out of all the elements after carbon (2). The hyperthermophilic nature of P. furiosus makes it a useful model organism in scientific research, and it has already been used in areas of space research, specifically how to engineer plants to survive the conditions on Mars (3).
Genome structure
The genome of P. furiosus is singular and circular, with a size of 1.908 Mb, containing 2,200 open reading frames (ORFs) (4). One-half of the ORFs encode for proteins, and around 700 are arranged in operons, suggesting that they encode for multi-subunit complexes (5). These flagella also allow for cell-to-cell connection.
Cell structure, metabolism & life cycle
P. furiosus is known as the “rushing fireball”, owing to its ability to grow at extrememly high temperatures and its round shape. It is a regular cocci with monopolar polytrichous flagella. When viewing P. furiosus, the first notable feature is that all of its around 50 flagella are attached to one pole of it round body. Like flagella found in many other organisms, these flagella are composed of glycoproteins. These flagella are unique in that they behave somewhat like stalks, allowing the organism to adhere to sand grains or other surfaces in its environment (6). The size of P. furiosus is approximately 0.8 μm- 1.5 μm. The organism is contained within a cellular envelope composed completely of glycoprotein.
P. furiosus can utlilize a wide range of carbon sources, and has been shown to thrive in lab when grown with yeast extract, maltose, cellobiose, β-glucans, starch and protein sources including tryptone, peptone, casein, and meat extracts. This organisms can utilize but will grow slowly on amino acids, organic acids, alcohols and carbohydrates such as glucose, fructose and lactose. The primary metabolic pathway used by P. furiosus is peptide fermentation, with side products H2 and CO2 . Metabolism is optimized in the presence of H2S. A recent study uncovered P. furiosus’s method for sugar metabolism, a modified Embden-Myerhof pathway (7). This organism can also surprisingly metabolize tungsten (8).
Ecology (including pathogenesis)
As previously mentioned, P. furiosus is a marine, anaerobe that inhabits deep sea vents, where temperatures reach over 100 °C. Its ideal pH range is from pH 5 to pH 9, but can withstand fluctuations. The organism is not pathogenic
Interesting feature
As mentioned earlier, P. furiosus has been used in studies researching how to engineer plants for life in outer space. Certain stresses are associated with space travel, including radiation, gravity, extreme temperatures, and drought, making space travel unbearable for plant life. Researchers at the University of North Carolina from the botany and microbiology departments are combining their skill sets in order to transfer the stress-resistant characteristics of P. furiosus to model plants, such as tobacco. The specific gene being transferred from P. furiosus to tobacco is superoxide reductase, which allows for the reduction of superoxide. Superoxide is a chemical signal given off by plants, when stressful conditions are experienced. When a plant releases this chemical for too long, the plant itself is harmed. By transferring the superoxide reductase gene to tobacco from P. furiosus, plants that are more tolerant of harsh conditions will be engineered (3).
References
(1) Fiala G. and Stetter, K.O. “Pyrococcus furiosus” sp. Nov. represents a novel genus of marine heterotrophic Archaebacteria growing optimally at 100”. “Archives of Microbiology”. 145(1), 56-61. http://www.springerlink.com/content/p50m447v02t436wp/. (2) “Tungsten.” Chemicool periodic table. 10/24/11. <http://www.chemicool.com/elements/tungsten.html>. (3) "NC State Researchers Redesign Life for Mars and Beyond | SpaceRef - Your Space Reference." SpaceRef - Space News as It Happens. Space Ref, 26 Oct. 2005. Web. 24 Oct. 2011. <http://www.spaceref.com/news/viewpr.html?pid=18122>. (4) Poole, F., Gerwe, B., Hopkins, R., Schut, G., Weinberg, M., Jenney, F., and Adams, M. “Defining gene in the genome of the hyperthemophilic archaeon, “pyrococcus furiosus”: implications for all microbial genomes”. “ American Society for Microbiology”. 2005. Volume 187. P. 7325-7332. (5) Jenney, F., Shah, C., Sugar, F., and Poole, F. “Pyrococcus furiosus protein production”. “SouthEast Collaboratory for Structural Research.” <http://www.secsg.org/pfu.htm>. (6) Nather, D., Reinhard, R., Gerhard, W., and Reinhard, W. “Flagella of Pyrococcus furiosus: multifunctional organelles, made for swimming, adhesion to various surfaces, and cell-cell contacts”. “ Journal of Bacteriology”. 206. Volume 188. P. 6915-6923. (7) Bevers, D. and Hagen, W. “ Tungsten metabolism Pyrococcus furiosus”. Delft University of Technology. 2007. < http://www.bt.tudelft.nl/fileadmin/Faculteit/TNW/Over_de_faculteit/Afdelingen/Biotechnology/Research/Research_Groups/Enzymology/Research_Projects/doc/ENZprBevers.pdf>.
