Pyrodictium abyssi is a gram-negative hyperthermophilic archaeum. It’s optimum growth temperature ranges from 97 up to 105 degrees Celsius with minimum and maximum growth temperatures of 80 to 110 degrees Celsius, respectively, although it can withstand temperatures up to 140 degrees Celsius.
Hot SpringThis bug grows at an optimum pH of 5.5 but can continue to grow across a range of 4.7 to 7.1 on the pH scale. Pyrodictium abyssi is a strict anaerobe and has the ability to grow across an NaCl concentration varying between 0.7% to 4.2%. It is a chemlithotroph that uses Hydrogen as a an energy source and Sulfur as an electron acceptor. In it’s optimum conditions, the bug was found to have a doubling time of 60 minutes. With the help of a scanning electron microscope, is was discovered that Pyrodictium abyssi has a disk shape with an average diameter of 0.3 – 2.5um and a thickness of about 0.025 – 0.05um and grows in an extensive three dimensional network of cannulae and cells. The cannulae are hollow tubes with a diameter of 25nm that may often be found bundled together with up to 100 tubes allowing multiple cells to be connected together.
Structural Network Found in Pyrodictium abyssiIn liquid cultures, Pyrodictium abyssi was found to grow in flakes ranging 1 to 10mm in diameter. This enormous size can probably be attributed to the strength of the network in which it resides. Using a process called freeze-etching in which the cells may be analyzed without losing their water content, the Pyrodictium abyssi cells were found to have flagella bundled with the cannulae externally to the cell.
Example of a Cell Observed Using Freeze-EtchingSpeculation has been made inferring that the cannulae may extend into the periplasmic space, but not into the cytoplasm of the cells, which would help explain for their incredibly stable structure. Another characteristic of the Pyrodictium abyssi cells is the external surface layer (termed s-layer) composed of a two-dimensional protein crystal cover with p6 symmetry designating the hexagonal nature of the structure and a lattice constant of 21nm referring to the distance between the repeats of the structure pattern.
Black SmokerBecause Pyrodictium abyssi is a strict anaerobe, it can most often be found deep in the ocean in heat vents termed black smokers. These vents are a result of the volcanic activity occurring beneath the earth floor and host extremely high temperatures suiting Pyrodictium abyssi perfectly. These temperatures push the limit at which life may grow and may help researchers understand how this limit exists on other planets and on our own. These microorganisms are also very important because of the enzymes they possess such as chaperone proteins and ATP synthases that continue to function properly without denaturing. Hyperthermophiles may also be of significant use in industry because they would enable functions to operate cheaper because they would require fewer enzymes to carry out the same processes.
Pyrodictium abyssi is of the domain Archaea, phylum crenarchaeota, class Thermoprotei, order Desulfurcoccales, family Pyrodictiaceae, genus Pyrodictium, and Species abyssi. It has a genome of length 1627 thousand base pairs and represents some of the prokaryotes dating back to the earliest times. Speculations have been made attributing high heat resistivity to high GC content although this was not supported in research around this archaea. It got it’s name from Pley and Stetter in 1991 who originally isolated it from hot abyssal marine sites.
Bibliography
Chapter 6: In Boiling Water. Hans Krause’s Research. Accessed 2 April 2003. <http://hanskrause.de/HKHPE/hkhpe_02_06.htm>.
Freeze Drying/Fracture/Etching. The Electron Microscopy Outreach Program. Created 1997. Accessed 2 April 2003. <http://em-outreach.sdsc.edu/web- course/Sec-II.A.6-A.7/Sec-II.A.6-A.7.html>.
McClockey, James. Medicinal Chemistry. University of Utah Health Sciences Center. Accessed 2 April 2003. <http://www.pharmacy.utah.edu/medchem/faculty/mccloskey/abstracts/15.ht ml>.
Perry, Jerome, and Staley, James, and Lory, Stephen. Microbial Life. Sunderland, Massachusetts: Sinauer Associates, Publishers, 2002.
Pyrodictium. German Collection of Microorganisms and Cell Cultures. Accessed 2 April 2003. <http://www.dsmz.de/bactnom/nam2519.htm#4241>.
Pyrodictium - Mikrobiologie/Archaeenzentrum. University of Regensburg. Created 5 February 2002. Accessed 2 April 2003. <http://www.biologie.uni- regensburg.de/Mikrobio/Stetter/Bilderhtml/pyrodictium.html>.
Pyrodictium Stetter et al. List of Bacterial names with Standing in Nomenclature. Created 28 March 1997. Accessed 2 April 2003. <http://www.bacterio.cict.fr/p/pyrodictium.html>.
Spheres of Activity. Scientific Faculty III Biology and Vorklini Medicine. Created 31 January 2001. Accessed 2 April 2003. <http://translate.google.com/translate?hl=en&sl=de&u=http://www.biologie.un regensburg.de/Mikrobio/Stetter/Gruppen/rachel.html&prev=/search%3Fq%3D s-layer%2Bpyrodictium%2Babyssi%26hl%3Den%26lr%3D%26ie%3DUTF- 8%26oe%3DUTF-8>.
*Disclaimer - This report was written by a student participaring in a microbiology course at the Missouri University of Science and Technology. The accuracy of the contents of this report is not guaranteed and it is recommended that you seek additional sources of information to verify the contents.
Return to Missouri S&T Microbiology HomePage Go to DJW's HomePage
This Document is maintained by djwesten@ mst.edu
