Spirochaeta americana

Scientific classification
Domain: Bacteria
Phylum: Spirochetes
Class: Spirochetes
Order: Spirochaetales
Family: Spirochaeta
Genus: Spirochaeta
Species: S. americana
Binomial name
Spirochaeta americana
Hoover, Pikuta and Bej 2003

Spirochaeta americana is a relatively newly discovered[1] single-celled extremophile. This haloalkaliphilic and obligately anaerobic bacterium can be found in the bleach-like highly alkaline, salty, deep waters of California's Mono Lake.[1][2]

Physical characteristics

S. americana has long helically coiled cells, is gram-negative, and is chemotrophic in its metabolism. Spirochaeta also have unique flagella, sometimes called axial filaments, which run lengthwise between the cytoplasmic membrane and outer membrane. These cause a twisting motion which allows the spirochaete to move about. Despite the extreme environment that they require, "their cell walls are very delicate, and it is difficult to keep them alive for long periods in the laboratory," says Dr. Elena Pikuta, one of the discoverers of S. americana.


S. americana thrives in the lake-bottom mud of Lake Mono, a 13 mile wide former monomictic volcanic basin which is fed by numerous small Sierra streams and which has no outflow except evaporation and Californian aqueducts, thereby continually increasing the concentration of salts and other minerals in its waters. Further mineral enrichment of these waters also occur due to the volcanically active area, such as when Negit Island erupted roughly 250 years ago.[3]

Surviving in deep, salty, alkaline lake mud of Lake Mono, the extreme conditions in which S. americana thrive have prompted its discoverers to explore Antarctica's Lake Untersee, hopefully to discover similar species.[4][5]


S. americana reproduces via transverse binary fission, where the cytoplasm divides transversely between two sets of nuclei, forming two dissimilar individuals, as do other Spirochaeta.[6]

Growth and metabolism

This bacterium grows in environments of 10 to 44 degrees Celsius with optimal growth at 37 degrees and prefers a pH balance of 9.5, similar to that of baking soda, hand soap, or a solution of household bleach in water.[7]

S. americana is capable of metabolizing D-glucose, fructose, maltose, sucrose, starch and D-mannitol and has as its waste H2, acetate, ethanol and formate.[1]


External links

  • Science a gogo - New Species Of Organism Excites Astrobiologists
  • Space.com - New Life Form Found in Mars-Like Conditions
This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and USA.gov, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for USA.gov and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.