Spirochaeta americana sp. nov., a new haloalkaliphilic, obligately anaerobic spirochaete isolated from soda Mono Lake in California

Abstract

A novel, obligately anaerobic, mesophilic, haloalkaliphilic spirochaete, strain ASpG1 T , was isolated from sediments of the alkaline, hypersaline Mono Lake in California, USA. Cells of the Gramnegative strain were motile and spirochaete-shaped with sizes of 0?2-0?2268-18 mm. 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 H 2 , acetate, ethanol and formate. Strain ASpG1 T 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 ASpG1 T with its most closely related species, Spirochaeta alkalica Z-7491 T , revealed a hybridization value of only 48?7 %. On the basis of its physiological and molecular properties, strain ASpG1 T appears to represent a novel species of the genus Spirochaeta, for which the name Spirochaeta americana is proposed (type strain ASpG1 T =ATCC BAA-392 T =DSM 14872 T ).The genus Spirochaeta contains a group of free-living, saccharolytic, obligately or facultatively anaerobic, helixshaped bacteria (Canale-Parola, 1977, 1984. Analysis of 16S rRNA gene sequences has shown that the spirochaetes represent a monophyletic phylum within the Bacteria (Paster et al., 1991). At the time of writing, the genus Spirochaeta contained 13 species of bacteria. These organisms occur in a wide variety of freshwater and marine environments (Canale-Parola, 1992), such as aquatic habitats (Spirochaeta aurantia) (Breznak & Canale-Parola, 1975), freshwater mud (Spirochaeta zuelzerae, Spirochaeta stenostrepta) (Canale-Parola, 1980), marine mud (Spirochaeta isovalerica, Spirochaeta litoralis) (Hespell & Canale-Parola, 1970;Harwood & Canale-Parola, 1983), oilfields (Spirochaeta smaragdinae) (Magot et al., 1997) and microbial mats (Teal et al., 1996). Some members of the genus Spirochaeta are microbial extremophiles that inhabit environments with extremes of salinity, alkalinity, pressure and/or temperature. The spirochaete extremophiles may harbour important enzymes and proteins and, consequently, are of particular interest to biotechnologists (Bermudes et al., 1987;Barth et al., 1991;Munson et al., 1993).Prior studies have shown that some species of the genus Spirochaeta are naturally resistant to sulfide concentrations at levels that inhibit the growth of many other microorganisms. The mesophilic halophile Spirochaeta halophila was isolated from black mud (smelling strongly of H 2 S) of Solar Lake, a high-salinity pond on the Sinai shore of the Gulf of Aqaba (Greenberg & Canale-Parola, 1976). The obligate anaerobe strain GS-2 is a mesophilic barophile that was isolated from sulfide-rich mud samples collected at a depth of 2550 m near deep-sea hydrotherm...

Spirochaeta cellobiosiphila sp. nov., a facultatively anaerobic, marine spirochaete

“…The results of this study indicate that strain SIP1 T is readily distinguishable from recognized spirochaetas on the basis of physiological and nutritional properties, as well as from the G+C content of its genomic DNA, which is the lowest among known spirochaetas (Table 1; Canale-Parola, 1984Aksinova et al, 1992;Hoover et al, 2003;Dröge et al, 2006;and references therein). Moreover, the 16S rRNA gene sequence of strain SIP1 T is phylogenetically distinct from those of all recognized spirochaetas (Fig.…”

“…Included are freshwater, marine and halophilic species, as well as alkaliphiles and thermophiles (CanaleParola, 1984(CanaleParola, , 1992Aksinova et al, 1992;Hoover et al, 2003;and references therein). Although most known spirochaetas are coiled or undulate in shape and are motile by means of periplasmic flagella, non-motile coccoid types have also been recognized as free-living forms (Ritalahti & Löffler, 2002 and as symbionts in the hindguts of termites (Dröge et al, 2006) and in the excretory organ of a Nautilus species (Pernice et al, 2007).…”

Spirochaeta dissipatitropha sp. nov., an alkaliphilic, obligately anaerobic bacterium, and emended description of the genus Spirochaeta Ehrenberg 1835

“…All tests to check for dependence on the CO 2{ 3 and Na + ions were carried out as described previously (Hoover et al, 2003;Pikuta et al, 2006a). Analytical procedures, optical microscopy, antibiotic-susceptibility and fatty acid analyses were also done as described previously (Hoover et al, 2003).…”

“…Analytical procedures, optical microscopy, antibiotic-susceptibility and fatty acid analyses were also done as described previously (Hoover et al, 2003).…”

“…The 16S rRNA gene was amplified as described previously (Hoover et al, 2003), except for the enzyme, which was Rainbow DNA polymerase (Extremozyme), and the fact that no DMSO was used in the reactions. The PCR product was purified by using a GeneClean Turbo kit (Qbiogene) and sequenced as described previously (Hoover et al, 2003).…”