Pyrobaculum aerophilum
Classification
Higher order taxa
Archaea; Crenarchaeota; Thermoprotei; Thermoproteales; Thermoproteaceae; Pyrobaculum
Species
Pyrobaculum aerophilum
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NCBI: Taxonomy |
Description and significance
Pyrobaculum aerophilum is a rod-shaped hyperthermophilic archaeum that was first isolated from boiling marine water in Maronti Beach, Italy. It was found that the archaeum grew optimally at 100°C and at pH 7.0. Both organic and inorganic compounds served as substrates during aerobic and anaerobic respiration. However, growth was inhibited by elemental sulfur. When discovered, pyrobaculum aerophilum resembled members from the genera Thermoproteus and Pyrobaculum because of its ability to transform into spherical bodies, which resemble golf balls. After its 16S rRNA was sequenced, the new archaeum displayed traits more characteristic of the genus Pyrobaculum and was therefore classified as pyrobaculum aerophilum. Pyrobaculum aerophilum derives its name from the Greek noun "aer" (air) and the Greek adjective "philos" (loving). Most species in the genus Pyrobaculum cannot live in the presence of oxygen; however, the pyrobaculum aerophilum can utilize oxygen for growth.
Pyrobaculum aerophilum cells were usually found to be 3 to 8 μm long and 0.6 μm wide. Motility is achieved using monopolar flagellation. Cells would transform into their terminal spherical phase mainly in the stationary-growth phase, at high nitrate concentrations or pH values exceeding 8.0. The spherical cells
Pyrobaculum aerophilumgrew in mediums ranging from temperatures 75 and 104°C. At the optimum temperature of growth, 100°C, the optimal doubling rate of the cells was observed to be 180 minutes. At the extreme temperature range of 75°C, the doubling rate of the cells drop to a rate of 5 days. There was no difference in growth when the archaeum was cultured either in anaerobic and anaerobic conditions. When living conditions was observed in different pH conditions, life was observed from a range of 5.8 to 9.0 The optimum rate of growth was observed at pH 7.0. However, when pyrobaculum aerophilum was introduced in an environment exceeding pH 8.0, no growth was observed. Also, when the pH was lowered to 5.5 or exceeded 9.0, rapid cell lysis occured. Different salt living conditions were also observed for growth and life. Optimal salt conditionns were observed at 1.5% NaCl. Growth of cells were observed when there were no traces of NaCl in the solution; however, once NaCl concentrations exceeded 3.55, no grwoth was observed.
Describe the appearance, habitat, etc. of the organism, and why it is important enough to have its genome sequenced. Describe how and where it was isolated. Include a picture or two (with sources) if you can find them.
Genome structure
Pyrobaculum aerophilum’’ is composed of a 2.2-megabase genome sequence. A whole genome analysis was computerized and experiments have confirmed that ‘’Pyrobaculum aerophilum’’ and possibly all Crenarchaea’’ lack 5’ untranslated regions in their mRNAs, and therefore do not appear to use a ribosome binding site. The lengths and dispersion of mononucleotide repeat-tracts uncovered that the Gs and Cs are highly precarious. This suggests that the archaeum could be lacking in a mismatch repair system.
Complete Genome Sequence, completed 12/12/2001 @ UCLA/CalTech
Summary: Length: 2,222,430 nt
GC Content: 51%
% Coding: 88%
Topology: circular Molecule: dsDNA
Genes: 2706
Protein coding: 2605
Structural RNAs: 96
Pseudo genes: none
Describe the size and content of the genome. How many chromosomes? Circular or linear? Other interesting features? What is known about its sequence?
Does it have any plasmids? Are they important to the organism's lifestyle?
Cell structure and metabolism
Pyrobaculum aerophilum has characteristics of both Thermoproteus and Pyrobaculum. The cylindrical rod-shape, the formation of terminal spheres, and the S-layer shows a close relationship to Thermoproteus and Pyrobaculum. However, the archaeum was unable to grow by sulfur respiration and growth was suppressed by the presence of elemental sulfur. The arcaheum was also found to grow by dissimilatory nitrate reduction, organic compounds, and thiosulfate. Interestingly, nitrate reduction has only been observed within the heterotrophic extreme halophiles.
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Ecology
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Pathology
How does this organism cause disease? Human, animal, plant hosts? Virulence factors, as well as patient symptoms.
Application to Biotechnology
Does this organism produce any useful compounds or enzymes? What are they and how are they used?
Current Research
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References
Edited by student of Rachel Larsen and Kit Pogliano
