A novel, obligately anaerobic, mesophilic, haloalkaliphilic spirochaete, strain ASpG1T, was isolated from sediments of the alkaline, hypersaline Mono Lake in California, USA. Cells of the Gram-negative strain were motile and spirochaete-shaped with sizes of 0·2–0·22×8–18 μm. Growth of the strain was observed between 10 and 44 °C (optimum 37 °C), in 2–12 % (w/v) NaCl (optimum 3 % NaCl) and between pH 8 and 10·5 (optimum pH 9·5). The novel strain was strictly alkaliphilic, required high concentrations of carbonates in the medium and was capable of utilizing d-glucose, fructose, maltose, sucrose, starch and d-mannitol. End products of glucose fermentation were H2, acetate, ethanol and formate. Strain ASpG1T was resistant to kanamycin and rifampicin, but sensitive to gentamicin, tetracycline and chloramphenicol. The G+C content of its DNA was 58·5 mol%. DNA–DNA hybridization analysis of strain ASpG1T with its most closely related species, Spirochaeta alkalica Z-7491T, revealed a hybridization value of only 48·7 %. On the basis of its physiological and molecular properties, strain ASpG1T appears to represent a novel species of the genus Spirochaeta, for which the name Spirochaeta americana is proposed (type strain ASpG1T=ATCC BAA-392T=DSM 14872T).
AusubelF. M., BrentR., KingstonR. E., MooreD. D., SeidmanJ. G., SmithJ. A., StruhlK.1987Current Protocols in Molecular Biology pp. 2.10–2.11 New York: Wiley;
BarthA. L., StrickerJ. A., MargulisL.1991; Search for eukaryotic motility proteins in spirochetes: immunological detection of a tektin-like protein in Spirochaeta halophila . Biosystems 24:313–319[CrossRef]
BermudesD., FracekS. P.Jr, LaursenR. A., MargulisL., ObarR., TzertzinisG.1987; Tubulinlike protein from Spirochaeta bajacaliforniensis . Ann N Y Acad Sci 503:515–527[CrossRef]
BischoffJ. L., StineS., RosenbauerR. J., FitzpatrickJ. A., StaffordT. W.Jr1993; Ikaite precipitation by mixing of shoreline springs and lake water. Mono Lake, California, USA: Geochim Cosmochim Acta 57:3855–3856[CrossRef]
BreznakJ. A., Canale-ParolaE.1975; Morphology and physiology of Spirochaeta aurantia strains isolated from aquatic habitats. Arch Microbiol 105:1–12[CrossRef]
Canale-ParolaE.1980; Revival of the names Spirochaeta litoralis , Spirochaeta zuelzerae , and Spirochaeta aurantia . Int J Syst Bacteriol 30:594[CrossRef]
Canale-ParolaE.1984; Genus I. Spirochaeta Ehrenberg 1835, 313AL. In Bergey's Manual of Systematic Bacteriologyvol. 1 pp 39–46Edited byKriegN. R., HoltJ. G. Baltimore: Williams & Wilkins;
Canale-ParolaE.1992; Free-living saccharolytic spirochetes: the genus Spirochaeta . In The Prokaryotes , 2nd edn. pp 3524–3536Edited byBalowsA., TrüperH. G., DworkinM., HarderW., SchleiferK.-H. New York: Springer-Verlag;
CouncilT. C., BennettP. C.1993; Geochemistry of ikaite formation at Mono Lake, California: implications for the origin of tufa mounds. Geology 21:971–974[CrossRef]
FracekS. P.Jr, StolzJ. F.1985; Spirochaeta bajacaliforniensis sp. n. from a microbial mat community at Laguna Figueroa. Baja California Norte, Mexico: Arch Microbiol 142317–325[CrossRef]
GerhardtP., MurrayR. G. E., CostilowR. N., NesterE. W., WoodW. A., KriegR. N., PhillipsG. B.editors1981Manual of Methods for General Bacteriology Washington, DC: American Society for Microbiology;
GillisM., De LeyJ., De CleeneM.1970; The determination of molecular weight of bacterial genome DNA from renaturation rates. Eur J Biochem 12:143–153[CrossRef]
HarwoodC. S., Canale-ParolaE.1983; Spirochaeta isovalerica sp. nov., a marine anaerobe that forms branched-chain fatty acids as fermentation products. Int J Syst Bacteriol 33:573–579[CrossRef]
HungateR. E.1969; A roll tube method for cultivation of strict anaerobes. In Methods in Microbiology vol 3B pp 117–132Edited byNorrisJ. R., RibbonsD. W. New York: Academic Press;
MagotM., FardeauM.-L., ArnauldO., LanauC., OlivierB., ThomasP., PatelB. K. C.1997; Spirochaeta smaragdinae sp. nov., a new mesophilic strictly anaerobic spirochete from an oil field. FEMS Micobiol Lett 155:185–191[CrossRef]
MesbahM., PremachandranU., WhitmanW. B.1989; Precise measurement of the G+C content of deoxyribonucleic acid by high-performance liquid chromatography. Int J Syst Bacteriol 39:159–167[CrossRef]
MunsonD., ObarR., TzertzinisG., MargulisL.1993; The ‘tubulin-like’ S1 protein of Spirochaeta is a member of the hsp65 stress protein family. Biosystems 31:161–167[CrossRef]
OremlandR. S., MillerL. G.1993; Biochemistry of natural gases in three alkaline, permanently stratified (meromictic) lakes. In The Future of Energy Gases pp 439–452Edited by HowellD. USGS Prof. Paper 1570
WayneL. G., BrennerD. J., ColwellR. R.9 other authors1987; International Committee on Systematic Bacteriology. Report of the ad hoc committee on reconciliation of approaches to bacterial systematics. Int J Syst Bacteriol 37:463–464[CrossRef]
ZhilinaT. N., ZavarzinG. A., RaineyF., KevbrinV. V., KostrikinaN. A., LysenkoA. M.1996; Spirochaeta alkalica sp. nov., Spirochaeta africana sp. nov., and Spirochaeta asiatica sp., alkaliphilic anaerobes from the continental soda lakes in Central Asia and the East African Rift. Int J Syst Bacteriol 46:305–312[CrossRef]