Hyperthermus

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A Microbial Biorealm page on the genus Hyperthermus

Electron micrographs of H. butylicus. a: Single cell with pili; b: Duplex form; c: Cells connected by a string of cytoplasm; d: Cell with a tail; e: Ghost exhibiting an S layer; f: Duplex form exhibiting an S layer and vacuoles. From Zillig, W. et al. "Hyperthermus butylicus, a Hyperthermophilic Sulfur-Reducing Archaebacterium That Ferments Peptides." J. of Bacteriol. July, 1990. Vol. 172, No. 7. p. 3962.

Classification

Higher order taxa

Archaea; Crenarchaeota; Thermoprotei; Desulfurococcales; Pyrodictiaceae

Species

Hyperthermus butylicus

NCBI: Taxonomy Genome

Description and significance

Hypperthermus is a hyperthermophilic, sulfur reducing archaeon that grows between 95 and 106°C and at pH of 7.0. Also, it forms H₂S from elemental sulfur and molecular hydrogen as a growth-stimulating accessory energy source but not by sulfur respiration. Further, the archaeon has a characteristic smell which composes of H₂S and butyl mercaptan and the odors of 1-butanol and phenylacetic acid.

Genome structure

The genome of Hyperthermus is currently being sequenced by the group from the University of Copenhagen. The G + C content of the DNA is around 55%.

Cell structure and metabolism

The cells of Hyperthermus are irregular spherical (around 1.5 µm in diameter) shape with edges between partially flattened surfaces. The ones that grow in higher temperature often contain vacuoles within their cytoplasm, sometimes immediately below the S layer. The archaeon utilizes peptide mixtures, obtained by various hydrolysis procedures (eg, Tryptone, Trypticase, Merck peptone from casein, gelatin, and a chymotryptic digest of casein) as carbon and energy sources. No growth has been observed with starch, maltose, sucrose, lactose, glucose, galactose, ribose, lactic acid, lactic acid ethylester, glyoxylate, pyruvate, oxalate, fumarate, maleate, malate, malonate, and formate. Hyperthermus is the first archaeon for which fermentation products have been identified. Its H₂S formation results in increased growth capacity without a major change in the nature of the products, except that it allows utilization of peptide-bound nitrogen. Therefore, this could possibly act as an accessory means to generate ATP.

Ecology

The strains of Hyperthermus butylicus were isolated from the sea floor of a hot, solfataric babitat on the coast of São Miguel Island in Azores, Portugal. With its ability to live at the temperature of 106°C, it is one of the most thermophilic archaea isolated so far. Also, interestingly, despite its being found in a marine environment,

References

Zillig, W., Holz, I., Janekovic, D., Klenk, H., Imsel, E., Trent, J., Wunderl, S., Fojaz, V. H., Coutinho, R., and Ferreira, T."Hyperthermus butylicus, a Hyperthermophilic Sulfur-Reducing Archaebacterium That Ferments Peptides." Journal of Bacteriology. July, 1990. Volume 172, Number 7. p. 3959-3965.