Pyrobaculum arsenaticum: Difference between revisions

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A Microbial Biorealm page on the genus LRMoore, Univ of Southern Maine
Contents
• 1[[Classification]]
o 1.1 Higher order taxa
o 1.2 Species
• 2 Description and significance
• 3 Genome structure
• 4 Cell and colony structure
• 5 Metabolism
• 6 Ecology
• 7 Pathology
• 8 References


===Classification===
===Classification===

Revision as of 17:26, 30 April 2013

This student page has not been curated.

Template:Pyrobaculum arsenaticum


Classification

Higher order taxa

Archaea; Crenarchaeota; Thermoprotei; Thermoproteales;Thermoproteaceae

Species

Pyrobaculum arsenaticum

Description and significance

The Archaean Pyrobaculum arsenaticum is a free living microbe found at the hot springs of Pisciarelli Salfataras in Naples, Italy. P. arsenaticum is gram negative, and its cells are cylindrical shaped rods with rectangular ends. The average length of each cell is 4μm, with most cells ranging from 3μm to 7μm. Pyrobaculum arsenaticum was the first hyperthermophylic microorganism shown to grow chemolithoautotrophically using arsenate as an electron acceptor with hydrogen.

Genome structure

The genome of Pyrobaculum arsenaticum has been measured 2,121,076 base pairs long contained in a single circular chromosome. Further analysis has revealed 2,408 predicted genes and a C+G content of 58.3mol%.

Cell and colony structure

Cells of Pyrobaculum arsenaticum are cylinder shaped rods averaging 4μm in length and 0.7 μm wide. While most cells range from 3 μm to 7 μm in length, cells up to a length of 20 μm have been observed. While colonies are growing, rods are often seen arranged in V-, X- or raft-shaped aggregates When colonies are grown with both acceptors present, thiosulfate and arsenate, a precipitate forms. The precipitate, known as realgar [As2S2], is seen as a yellow-orange flocculent mass in the culture medium.

Metabolism

This species is characterized as a hyperthermophylic, facultative autotroph. During anaerobic respiration, Pyrobaculum arsenaticum uses Hydrogen as an electron source and reduces arsenate to form arsenite. As a lithoautotroph, CO2 is used as a carbon source. Elemental sulfur can also be utilized as an alternate electron acceptor for autotrophic growth. When grown organotrophically, Pyrobaculum arsenaticum uses arsenate and thiosulfate or arsenate and cysteine as terminal electron acceptor, resulting in the production of arsenic sulfide minerals called realgar.



Ecology

Pyrobaculum arsenaticum was discovered in high temperature environment of hot springs, specifically those of Naples, Italy. Further studies have shown that Pyrobaculum arsenaticum gorws optimally at 90C, and is able to grow at temperatures ranging from 68C to 100C. At 65C and 102C Pyrobaculum arsenaticum is unable to grow.


References

Huber, R. et al. 2000. Respiration of arsenate and selenite by hyperthermophylic archaea. Systematic and Applied Microbiology. 23:305-314

Ehrlich, H. 2009 Geomicrobiology. Fifth Edition. Taylor and Francis Group, LLC. 14:254-256

Edited by Robert Walsh of Dr. Lisa R. Moore, University of Southern Maine, Department of Biological Sciences, http://www.usm.maine.edu/bio Category: Uncurated Pages