Thermotoga neapolitana

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A Microbial Biorealm page on the genus Thermotoga neapolitana


Higher order taxa

Bacteria; Thermotogae; Thermotogae; Thermotogales; Thermotogaceae; Thermotoga


NCBI: Taxonomy

Thermotoga neapolitana

Description and significance

Thermotoga neapolitana cells are gram-negative rods, approximately 1.5 to 11 ~tm long and 0.6 Ixm wide, and can occur singly and in pairs. They have an unusually thick periplasmic cell wall layer, which, when compared with characteristic gram-negative cell walls, is covered with a more electron-dense outer layer. Cells are immotile, possessing no flagella. They are surrounded by a sheath-like outer structure that usually balloons over the ends; a "toga," as it were, from which the genus name is derived. Its species name is in reference to the location of its original isolation in 1986: a shallow marine sediment in a volcanic region near Lucrino, Bay of Naples, Italy. As one would expect from its location of origin, T. neapolitana is an extremely thermophilic bacteria, growing between 55 and 90 degrees Celsius, with an optimum growth temperature of 77 degrees Celsius. It is viable between pH 5.5 and 9; at pH 7 its growth is at a maximum.

There are three lines of reasoning that outline the significance of T. neapolitana having its genome sequenced. Firstly, due to its requiring only minimal anoxic precautions, and its ability to be grown on both solid and liquid media via materials that are readily available, the utilization of T. neapolitana is a preferable method for understanding the basic molecular biology of extreme thermophiles. Secondly, as it is closely related to the type species Thermotoga maratima, comparison of these two genomes will enable researchers to identify chromosomal segments that have undergone DNA rearrangements after the lineages diverged from a common ancestor. Lastly, current research has implicated T. neapolitana as a potentially viable source of hydrogen production. Current methods of hydrogen production are both costly and environmentally unfriendly; in a market in which hydrogen demands are expected to only increase, a new biological method for hydrogen production is very desirable. Sequencing T. neapolitana's genome will further these ends by allowing for deeper understanding of its nature.

Genome structure

Thermotoga neapolitana has one circular chromosome, and a genome that is 1800kb in size. The molar ratio of guanine plus cytosine in the DNA has been calculated to be 41.3 mol%. Its DNA homology with Thermotoga maritima has been found to be approximately 24%. Thermotoga neopolitana strain ATCC 49045 (NS-E) is currently having its genome sequenced by the TIGR Institute for the purposes of comparative genome analysis. Its project ID is: 12534.

Cell structure and metabolism

Thermotoga neapolitana survives by scavenging biomolecules. It catabolizes both mono- and polysaccharides, including galactose, glucose, lactose, maltose, ribose, starch, sucrose, and xylose. In contrast to other Thermotogales, amino acids do not support their growth.

Rather than using oxygen as its electron acceptor in metabolism, T. neapolitana uses sulfur. Therefore, rather than converting oxgyen to water, T. neapolitana reduces elemental sulfur to hydrogen sulfide. However, it is not dependent upon sulfur for growth.

If the available sulfur is organically bound, considerable hydrogen gas can be produced, therefore producing hydrogen gas from organic waste products. Describe any interesting features and/or cell structures; how it gains energy; what important molecules it produces.


Describe any interactions with other organisms (included eukaryotes), contributions to the environment, effect on environment, etc.


As an extremely thermophilic eubacteria, Thermotoga neapolitana is not viable under the conditions that support most life. It therefore has no known diseases associated with it, and at present has not been found to be pathogenic.

Application to Biotechnology

Does this organism produce any useful compounds or enzymes? What are they and how are they used?

A number of thermostable enzymes such as alkaline phosphatase are produced by this bacterium and may be of use for industrial purposes.

Current Research

Enter summaries of the most recent research here--at least three required


[Sample reference] Takai, K., Sugai, A., Itoh, T., and Horikoshi, K. "Palaeococcus ferrophilus gen. nov., sp. nov., a barophilic, hyperthermophilic archaeon from a deep-sea hydrothermal vent chimney". International Journal of Systematic and Evolutionary Microbiology. 2000. Volume 50. p. 489-500.

Edited by student of Rachel Larsen