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PubMed1989

Chemotaxis mutants of Spirochaeta aurantia.

Five Spirochaeta aurantia chemotaxis mutants were isolated. One mutant (the che-101 mutant) never reversed, one (the che-200 mutant) flexed predominantly, two (the che-300 and che-400-1 mutants) exhibited elevated reversal frequencies, and one (the che-400 mutant) exhibited chemotactically unstimulated behavior similar to that of the wild-type strain. The che-101 and che-400 mutants were essentially nonchemotactic, whereas the che-200, che-300, and che-400-1 mutants showed impaired chemotactic responses. Protein methylation in response to attractant addition appeared normal in all of the mutants. Compared with the wild type, all of the mutants exhibited significantly altered membrane potential responses to the attractant xylose.

Cell Membrane↗
PubMed1989

Cloning and sequence analysis of flaA, a gene encoding a Spirochaeta aurantia flagellar filament surface antigen.

Spirochaeta aurantia DNA that coded for an antigenic determinant of the flagellin associated with the filament surface of the periplasmic flagella was isolated. When expressed in Escherichia coli, the antigenic polypeptide had an apparent molecular weight of 37,000. Sequence analysis of the antigen-encoding DNA revealed the presence of an open reading frame that determined a polypeptide with a predicted molecular weight of 31,241. This polypeptide showed a region of identity with the N-amino-terminal region of the 39,000- and 37,000-dalton flagellins of the distantly related spirochetes Treponema phagedenis and Treponema pallidum, respectively (S. J. Norris, N. W. Charon, R. G. Cook, M. D. Fuentes, and R. J. Limberger, J. Bacteriol. 170:4072-4082, 1988). The region of identity in the deduced S. aurantia polypeptide was preceded by a possible signal sequence and signal peptidase cleavage site.

Amino Acid Sequence↗
PubMed1991

Nucleotide sequence and analysis of a gene encoding anthranilate synthase component I in Spirochaeta aurantia.

A Spirochaeta aurantia DNA fragment containing the trpE gene and flanking chromosomal DNA was cloned, and the sequence of the trpE structural gene plus 870 bp upstream and 1,257 bp downstream of trpE was determined. The S. aurantia trpE gene codes for a polypeptide of 482 amino acid residues with a predicted molecular weight of 53,629 that showed sequence similarity to TrpE proteins from other organisms. The S. aurantia TrpE polypeptide is not more closely related to the other published spirochete TrpE sequence (that of Leptospira biflexa) than to TrpE polypeptides of other bacteria. Two additional complete open reading frames and one partial open reading frame were identified in the sequenced DNA. One of the complete open reading frames and the partial open reading frame are upstream of trpE and are encoded on the DNA strand opposite that containing trpE. The other open reading frame is downstream of trpE and on the same DNA strand as trpE. On the basis of the results of a protein sequence data base search, it appears that trpE is the only tryptophan biosynthesis gene in the sequenced DNA. This is in contrast to L. biflexa, in which trpE is separated from trpG by only 64 bp.

Amino Acid Sequence↗
PubMed1991

N-terminal amino acid sequences and amino acid compositions of the Spirochaeta aurantia flagellar filament polypeptides.

The amino-terminal sequences and amino acid compositions of the three major and two minor polypeptides constituting the filaments of Spirochaeta aurantia periplasmic flagella were determined. The amino-terminal sequence of the major 37.5-kDa outer layer polypeptide is identical to the sequence downstream of the proposed signal peptide of the protein encoded by the S. aurantia flaA gene. However, the amino acid composition of the 37.5-kDa polypeptide is not in agreement with that inferred from the sequence of flaA. The 34- and 31.5-kDa major filament core polypeptides and the 33- and 32-kDa minor core polypeptides show a striking similarity to each other, and the amino-terminal sequences of these core polypeptides show extensive identity with homologous proteins from members of other genera of spirochetes. An additional 36-kDa minor polypeptide that occurs occasionally in preparations of S. aurantia periplasmic flagella appears to be mixed with the 37.5-kDa outer layer polypeptide or a degradation product of this polypeptide.

Amino Acid Sequence↗
PubMed1992

Glucose catabolism by Spirochaeta thermophila RI 19.B1.

Spirochaeta thermophila RI 19.B1 (DSM 6192) fermented glucose to lactate, acetate, CO2, and H2 with concomitant formation of cell material. The cell dry mass yield was 20.0 g/mol of glucose. From the fermentation balance data and knowledge of the fermentation pathway, a YATP of 9.22 g of dry mass per mol of ATP was calculated for pH-uncontrolled batch-culture growth on glucose in a mineral medium. Measurement of enzyme activities in glucose-grown cells revealed that glucose was taken up by a permease and then subjected to ATP-dependent phosphorylation by a hexokinase. Glucose-6-phosphate was further metabolized to pyruvate through the Embden-Meyerhof-Parnas pathway. The phosphoryl donor for phosphofructokinase activity was PPi rather than ATP. This was also found for the type strain of S. thermophila, Z-1203 (DSM 6578). PPi was probably formed by pyrophosphoroclastic cleavage of ATP, with recovery of the resultant AMP by the activity of adenylate kinase. All other measured kinase activities utilized ATP as the phosphoryl donor. Pyruvate was further metabolized to acetyl coenzyme A with concomitant production of H2 and CO2 by pyruvate synthase. Lactate was also produced from pyruvate by a fructose-1,6-diphosphate-insensitive lactate dehydrogenase. Evidence was obtained for the transfer of reducing equivalents from the glycolytic pathway to hydrogenase to produce H2. No formate dehydrogenase or significant ethanol-producing enzyme activities were detected.

Fermentation↗
PubMed2000

Spirochaeta aurantia has diacetyl chloramphenicol esterase activity.

The free-living spirochete Spirochaeta aurantia was nearly as susceptible to diacetyl chloramphenicol, the product of chloramphenicol acetyltransferase, as it was to chloramphenicol itself. This unexpected susceptibility to diacetyl chloramphenicol was wholly or partly the consequence of intrinsic carboxylesterase activity, as indicated by high-performance liquid chromatography, thin-layer chromatography, and microbiological assays. The esterase converted the diacetate to chloramphenicol, thus inhibiting spirochete growth. The esterase activity was cell associated, reduced by proteinase K, eliminated by boiling, and independent of the presence of either chloramphenicol or diacetyl chloramphenicol. S. aurantia extracts also hydrolyzed other esterase substrates, and two of these, alpha-napthyl acetate and 4-methylumbelliferyl acetate, identified an esterase of approximately 75 kDa in a nondenaturing gel. Carboxylesterases occur in Streptomyces species, but in this study their activity was weaker than that of S. aurantia. The S. aurantia esterase could reduce the effectiveness of cat as either a selectable marker or a reporter gene in this species.

Carboxylic Ester Hydrolases↗
PubMed1968

Fine structure of Spirochaeta stenostrepta, a free-living, anaerobic spirochete.

The fine structure of Spirochaeta stenostrepta strain Z1, a free-living anaerobic spirochete, was studied by electron microscopy. The organism possessed a coiled protoplasmic cylinder, an axial filament inserted subterminally, and a loosely fitting sheath which enclosed both the protoplasmic cylinder and the axial filament. The axial filament consisted of two fibrils partially overlapping in a 1-2-1 arrangement. The axial fibrils appeared to possess a sheath surrounding an inner core. Both inner core and sheath were apparently enclosed in a cross-striated tubular structure, which was itself surrounded by an outer sheath. The axial filament exhibited a basal hook. A disc- or mushroom-shaped structure, possibly consisting in part of cytoplasmic membrane, was observed at the insertion end of isolated filaments. The protoplasmic cylinder had a distinctive surface structure consisting of an array of tightly packed, longitudinally arranged helices measuring 2.0 to 2.5 nm in diameter. This layer of helices lay below the outer cell sheath and the axial filament. Ballistic disintegration loosened the helical array, causing individual helices or segments of helices to become separated from the cell. The function of this layer of helices is still obscure.

Cytoplasm↗
PubMed1969

Spirochaeta aurantia, a pigmented, facultatively anaerobic spirochete.

A strain of Spirochaeta aurantia was isolated from mud by a procedure involving migration of the organisms through cellulose ester filter discs (0.3-mum pore diameter) onto the surface of culture plates. The helical cells measured 0.3 by 10 to 20 mum during exponential growth. Electron microscopy showed the presence of two subterminally inserted axial fibrils partially overlapping in a 1-2-1 arrangement. An outer envelope, exhibiting a polygonal substructure, was observed. The spirochete grew either aerobically or anaerobically, with aerobic yields of 9.8 x 10(8) cells per ml and anaerobic yields of 3.0 x 10(8) cells per ml. The organism used carbohydrates, but not amino acids, as energy sources. Amino acids served as sole nitrogen sources, whereas inorganic ammonium salts did not. The presence of biotin and thiamine in the medium was required for growth. Growing cells fermented maltose mainly to carbon dioxide, hydrogen, ethyl alcohol, and acetic acid. Small amounts of formic and lactic acids, acetoin, and diacetyl were produced. Cells of S. aurantia growing aerobically produced a yellow-orange pigment. Chemical analysis indicated that the pigment was carotenoid in nature, its main component being lycopene or a similar compound. S. aurantia is not closely related to the leptospires, since it lacks both the hemolytic antigen and the hooked ends typical of the latter organisms. Furthermore, the guanine plus cytosine content in the deoxyribonucleic acid of S. aurantia (66.8 moles%) differs drastically from that of leptospires.

Acetates↗
PubMed2004

Nature of the genome of the saprophytic spirochete Spirochaeta aurantia and its ribosomal RNA operons.

Using restriction endonucleases DraI, AseI, and I-CeuI in conjunction with pulsed-field gel electrophoresis, we have shown that Spirochaeta aurantia M1 possesses a circular 3.98-Mb genome. This is the second largest spirochete chromosome yet analyzed. The observation that the latter enzyme cuts in 3 places suggests the presence of 3 copies of the large subunit (23S) rRNA gene (rrl), which was confirmed by Southern hybridizations. The complete sequence of 2 of the ribosomal RNA operons was determined, revealing that their structure resembled that of the typical member of the bacterial superkingdom: rrs (16S; 1561 bp), tRNA, rrl (23S; 2972 bp), and rrf (5S; 110 bp). The S. aurantia rrs-rrl intergenic regions, as with Treponema denticola, contain genes specifying a 73-nt tRNA(Ala) (anticodon TGC) and a 77-nt tRNA(Ile) (anticodon GAT).

Base Sequence↗
PubMed1976

Direct transfer of the phosphoryl moiety of mannitol 1-phosphate to [14C]mannitol catalyzed by the enzyme II complexes of the phosphoenolpyruvate: mannitol phosphotransferase systems in Spirochaeta aurantia and Salmonella typhimurium.

Spirochaeta aurantia possesses a phosphoenolpyruvate:mannitol phosphotransferase system which catalyzes the transmembrane transport and phosphorylation of mannitol. In vitro studies showed that both phosphoenolpyruvate and mannitol 1-phosphate could serve as phosphate donors. The phosphoenolpyruvate-dependent reaction required two soluble proteins, Enzyme SI and HPr, and an integral membrane complex, Enzyme SII. Only Enzyme SII was required for the mannitol 1-phosphate-dependent reaction. Enzyme II-dependent transphosphorylation of sugars was also demonstrated in eubacterial extracts. The results lead to the suggestion that the Enzyme II complexes of bacterial phosphotransferase systems possess nonoverlapping binding sites for sugar and sugar phosphate.

Edetic Acid↗