- Magnetospirillum
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Magnetospirillum magnetotacticum strain MS-1 Scientific classification Kingdom: Bacteria Phylum: Proteobacteria Class: Alpha Proteobacteria Order: Rhodospirillales Family: Rhodospirillaceae Genus: Magnetospirillum Species: M. magnetotacticum Binomial name Magnetospirillum magnetotacticum Magnetospirillum magneticum strain AMB-1 Scientific classification Kingdom: Bacteria Phylum: Proteobacteria Class: Alpha Proteobacteria Order: Rhodospirillales Family: Rhodospirillaceae Genus: Magnetospirillum Species: M. magneticum Binomial name Magnetospirillum magneticum Magnetospirillum gryphiswaldense Scientific classification Kingdom: Bacteria Phylum: Proteobacteria Class: Alpha Proteobacteria Order: Rhodospirillales Family: Rhodospirillaceae Genus: Magnetospirillum Species: M. gryphiswaldense Binomial name Magnetospirillum gryphiswaldense Magnetospirillum is a Gram-negative, microaerophilic genus of magnetotactic bacterium, first isolated from pond water by the microbiologist R. P. Blakemore in 1975.[1] It is characterized by a spirillar, or helical, morphology. It is also a motile bacterium owing to the presence of a polar flagellum at each end. Four species have been described: Magnetospirillum magnetotacticum strain MS-1[2] (originally classified as Aquaspirillum magnetotacticum;[3]) Magnetospirillum magneticum strain AMB-1;[4] Magnetospirillum gryphiswaldense;[2] and Magnetospirillum bellicus.[5]
The typical habitat of Magnetospirillum consists of shallow fresh water and sediments, characterized by low concentrations of oxygen for growth (microaerophilic) where it lives in the upper portion of the sediment (oxic/anoxic interface). It prefers an oxygen gradient of approximately 1-3%.
Probably the most peculiar characteristic of Magnetospirillum is its capacity to orient itself according to Earth's magnetic field, an ability which has been named magnetotaxis. This is achieved through the presence into the bacterium's cytoplasm of special organelles called magnetosomes. Magnetospirillum also resorts to aerotaxis, in order to remain in favourable O2 concentration conditions.
Purification of magnetosomes is accomplished by use of a magnetic separation column after disruption of the cell membrane. If a detergent is used on purified magnetosomes, they tend to agglomerate rather than staying in chain form.
Due to the high quality of the single-domain magnetic crystals there is also a commercial interest in the bacteria. The crystals are thought to have the potential to produce magnetic tapes and magnetic target drugs.[6]
Notes
References
- Schleifer, K. H.; Schuler, D.; Spring, S.; Wiezenegger, M.; Amann, R.; Ludwig, W.; Kohler, M. (1991). "The genus Magnetospirillum gen. nov. description of Magnetospirillum gryphiswaldense sp. nov. and transfer of Aquaspirillum magnetotacticum to Magnetospirillum magnetotacticum comb. nov". Syst. Appl. Microbiol. 14: 379–385.
- Maratea, D.; Blakemore, R. P. (1981). "Aquaspirillum magnetotacticum sp. Nov., a Magnetic Spirillum". International Journal of Systematic Bacteriology 31 (4): 452–455. doi:10.1099/00207713-31-4-452.
- Blakemore, Richard (1975). "Magnetotactic bacteria". Science 190 (4212): 377–379. doi:10.1126/science.170679. PMID 170679.
- Matsunaga, Tadashi; Sakaguchi, Toshifumi; Tadokoro, Fumihiko (1991). "Magnetite formation by a magnetic bacterium capable of growing aerobically". Appl. Microbiol. Biotechnol. 35: 651–655.
- Thrash, J. C.; Ahmadi, S.; Torok, T.; Coates, J. D. (2010). "Magnetospirillum bellicus sp. Nov., a Novel Dissimilatory Perchlorate-Reducing Alphaproteobacterium Isolated from a Bioelectrical Reactor". Applied and Environmental Microbiology 76 (14): 4730. doi:10.1128/AEM.00015-10. PMC 2901729. PMID 20495050. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2901729.
- "Magnetospirillum magnetotacticum MS-1". The Joint Genome Institute. 26-Aug-2010. http://img.jgi.doe.gov/cgi-bin/pub/main.cgi?section=TaxonDetail&page=taxonDetail&taxon_oid=638341121.
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