Pikuta EV, Hoover RB, Bej AK, Marsic D, Whitman WB, Krader P
Spirochaeta dissipatitropha sp. nov., an alkaliphilic, obligately anaerobic bacterium, and emended description of the genus Spirochaeta Ehrenberg 1835. [JOURNAL ARTICLE]
Int J Syst Evol Microbiol 2009 Jun 19.
A novel obligately anaerobic, mesophilic, alkaliphilic spirochete, strain ASpC2T, was isolated from an anaerobic sediment of the alkaline, hypersaline Owens Lake in California, USA. The Gram-negative cells are motile with helical shape and sizes of 0.23x8.0-18.0 mum. Growth occurs within the following ranges: temperature 13 - 41 degrees C; with optimal growth at 35 degrees C; NaCl concentration 1-3 % (w/v); optimum NaCl 2 % (w/v) and pH 7.8-10.5; optimum pH 10.0. The novel isolate is strictly alkaliphilic and requires high concentrations of carbonate-ions in the medium. New isolate utilizes some sugars, some organic acids, some amino acids, casamino acids, yeast extract and peptone. The main end products of glucose fermentation are: CO2 and acetate. Strain ASpC2T is resistant to kanamycin and rifampin, but sensitive to ampicillin, chloramphenicol, gentamycin and tetracycline. The G+C content in DNA of the new isolate is 43.8 mol%, genome size is 6x10(8) Daltons, Tm of genomic DNA is 71 degrees C. DNA-DNA hybridization exhibited 46 % homology with the phylogenetically closest species, Spirochaeta asiatica strain Z-7491T. On the basis of physiological and molecular properties, the taxonomic position for new isolate occurs on the level of a separate new species within the Spirochaeta genus. The name Spirochaeta dissipatitropha sp. nov., is suggested for the new isolate (type strain ASpC2T = ATCC BAA-1083T = JCM 12856T). S. dissipatitropha ASpC2T is the second strain after S. smaragdinae SEBR 4228T that is able to use proteolysis products (as the sole energy source) and additional tests have shown that other halo-alkaliphilic spirochetes (S. americana, S. alkalica, and S. africana) are also able to grow on yeast extract alone, and therefore, an emended description for the genus Spirochaeta is given.
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