Does Thermus Represent Another Deep Eubacterial Branching?

Hartmann, Roland K.; Wolters, Jörn; Kröger, Bernd; Schultze, Sabine; Specht, Thomas; Erdmann, Volker A.

doi:10.1016/s0723-2020(89)80020-7

Cited by 42 publications

(24 citation statements)

References 25 publications

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“…The complete sequence of the 16s rRNA gene of HB8 has been published previously by Murzina et al (29). However, Hartmann et al (16) observed two discrepancies in their data, one in the V6 region and the other, a missing AC, at positions 1245 and 1246 (E. coli numbering). The sequence obtained by us is in accord with the results of Hartmann et al, and this version was used in our analyses.…”

Section: Resultsmentioning

confidence: 93%

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Phylogeny of Twenty Thermus Isolates Constructed from 16S rRNA Gene Sequence Data

Saul

Rodrigo

Reeves

et al. 1993

International Journal of Systematic Bacteriology

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The sequences of the 16s rRNA genes of 20 lltermus isolates were determined to a high fidelity by using automated DNA sequencing and fluorescent-dye-labelled primers. The strains tested included members of the three validly named Thennus species and representatives of major taxonomic clusters defined previously for this genus. The parsimony method was used to reconstruct the phylogeny of the strains from the aligned sequences, and a bootstrap analysis revealed a number of well-supported clades. Our results are not consistent with groupings inferred from numerical taxonomy data but support the conjecture that the genus Thennus contains more species than the three currently recognized species.Since the original description of the genus Thermus by Brock and Freeze (4), the ubiquitous nature of members of this taxon has been demonstrated by the ready isolation of strains from neutral-pH thermal areas around the world (reviewed in reference 48). The genus Thermus represents a deep eubacterial branch (16) and contains three validly named species: Thermus aquaticus (4), Thermus ruber (26), and Thermus filiformis (20). Many other Thermus isolates have been described in some detail but have not yet been validly named; the taxonomy of the genus is still incomplete. While there is general agreement that T. ruber and T. aquaticus are taxonomically and phylogenetically distinct (17), it is still unclear whether the yellow-pigmented isolates that grow at 70°C constitute a single species or more than one species. In a numerical taxonomic study Hudson et al. (21) discerned eight species groups which were separated at a simple matching coefficient value of 65%, while Williams (47) suggested that there are at least four genospecies on the basis of DNA-DNA hybridization data and other properties. In both cases there were strong indications that strains isolated from the same thermal region shared common properties and grouped together. A comparison of results is difficult because different strains have been used in different studies.In this study the sequences of the 16s rRNA genes of 20 Thermus strains were determined by using a procedure developed specifically to provide high-fidelity data with an automated DNA sequencer, and the aligned sequences were subjected to phylogenetic analysis. The complete 16s rRNA gene sequence of "Thermus thermophilus" HB8 (29) and a partial sequence of T. aquaticus (45) were available from other sources, but the results described below were derived from our own sequence versions. The 20 strains included representatives of the major clusters defined in the study of Hudson et al. (21) and the three validly named species, as well as two "T. thermophilus" strains (HB8 and HB27) and '' Thermus flavus . "Phylogenetic systematics is a two-stage process. The first stage is the estimation of a phylogenetic tree, and for this we used aligned sequence data and reconstructed the phylogeny by using the criterion of maximum parsimony (44). The * Corresponding author. second stage is the translation of the phyl...

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Section: Resultsmentioning

confidence: 93%

“…The genus Thermus represents a deep eubacterial branch (16) and contains three validly named species: Thermus aquaticus (4), Thermus ruber (26), and Thermus filiformis (20). Many other Thermus isolates have been described in some detail but have not yet been validly named; the taxonomy of the genus is still incomplete.…”

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confidence: 99%

Phylogeny of Twenty Thermus Isolates Constructed from 16S rRNA Gene Sequence Data

Saul

Rodrigo

Reeves

et al. 1993

International Journal of Systematic Bacteriology

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“…and D. radiodurans is revealed by a specific MAb. The availability of a collection of MAbs against different regions of the S-layer protein (SlpA) from T. thermophilus HB8 allowed us to analyze the existence of conserved domains within the S-layer proteins of different isolates belonging to the Thermus-Deinococcus phylogenetic group (14). For this purpose, we purified cell envelope fractions from T. thermophilus HB8, T. thermophilus HB27, Thermus sp.…”

Section: Resultsmentioning

confidence: 99%

A conserved motif in S-layer proteins is involved in peptidoglycan binding in Thermus thermophilus

et al. 1996

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There is experimental evidence to suggest that the 100-kDa S-layer protein from Thermus thermophilus HB8 binds to the peptidoglycan cell wall. This property could be related to the presence of a region ( Paracrystalline surface layers (S-layers) are commonly found within prokaryotes belonging to different phylogenetic groups (22). As the outermost envelope, the functions of S-layers are related to their interaction with the specific environment in which these organisms grow. However, their constant presence in bacteria belonging to the oldest phylogenetic groups and the severe defects shown by S-layer-defective mutants in these groups (13, 17) suggest that primitive S-layers could have played a role essentially related to the maintenance of the cell morphology and envelope integrity (2, 22).Three-dimensional reconstruction of S-layers has revealed features common among them (22), independently of differences in their specific functions. Essentially, S-layers present a smooth surface which faces outside and a more corrugated one that binds them to the underlying envelope, whatever its nature (peptidoglycan, outer membrane, or lipopolysaccharide). At higher resolution, this corrugated side shows up as wide columns, located at the main symmetry axis, that are interconnected through a network of thin contacts at the surface. This network of contacts generates the smooth face of the S-layer.This common morphology of the S-layer is built up by a single protein component that is folded in at least two clear domains: a heavy domain, which interacts with other equivalent domains to form the wide columns that bind the S-layer to the cell, and one or more light domains to connect them at the surface (28). However, the resolution of the three-dimensional models available at present does not allow a correlation between structural topology and protein sequence to be made. In addition, the scarcity of both S-layer models and protein sequences and the high divergence found within the latter do not in general allow association of specific sequence motifs or patterns with specific structural features. However, in a recent article, Lupas et al. (20) have described the existence of one or more copies of a protein domain known as the S-layer homology (SLH) region in a number of S-layers and regular membrane proteins from unrelated bacteria. On the basis of the homology, also found with extracellular enzymes from grampositive bacteria (20), a peptidoglycan-binding function was tentatively assigned to this domain.Despite belonging to a phylogenetic group different from that of gram positive bacteria, the 100-kDa S-layer protein from Thermus thermophilus HB8 was included among those that contain an SLH domain (11,20). In this 917-amino-acidlong protein (SlpA), the SLH domain was found from amino acid positions 28 to 87, thus suggesting the possibility of an interaction in vivo between the S-layer and the peptidoglycan. Two biochemical data can be argued to support the existence of such interactions. First, the solubilization of SlpA w...

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“…Several rRNA-based phylogenetic investigations indicate a distant relationship between the Deinococcus/Thermus and the GNS lines of descent (7,9,28,31). However, Weisburg et al (29) suggested that the clustering observed in the rRNA-derived phylogenies was an artifact caused by thermophilic convergence due to high GϩC ratios of the rRNA.…”

Section: Discussionmentioning

confidence: 99%

Characterization of novel long-chain 1,2-diols in Thermus species and demonstration that Thermus strains contain both glycerol-linked and diol-linked glycolipids

Wait¹,

Carreto²,

Nobre³

et al. 1997

J Bacteriol

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In this study, we purified and characterized tetra-and triglycosyl glycolipids (GL-1 and GL-2, respectively) from two different colonial forms of Thermus scotoductus X-1, from T. filiformis Tok4 A2, and from T. oshimai SPS-11. Acid hydrolysis of the purified glycolipids liberated, in addition to the expected long-chain fatty acids, two components which were identified by gas chromatography-mass spectrometry as 16-methylheptadecane-1,2-diol and 15-methylheptadecane-1,2-diol. Fast atom bombardment mass spectrometry of the intact glycolipids indicated that a major proportion consisted of components with glycan head groups linked to long-chain 1,2-diols rather than to glycerol, although in all cases glycerol-linked compounds containing similar glycan head groups were also present. As in other Thermus strains, the polar head group of GL-1 from T. filiformis Tok4 A2 and from T. scotoductus X-1 colony type t2 was a glucosylgalactosyl-(N-acyl)glucosaminylglucosyl moiety. However, GL-2 from T. scotoductus X-1 colony type t1 and from T. oshimai SPS-11 was a truncated analog which lacked the nonreducing terminal glucose. Long-chain 1,2-diols have been previously reported in the polar lipids of Thermomicrobium roseum and (possibly) Chloroflexus aurantiacus, but to our knowledge, this is the first report of their detection in other bacteria and the first account of the structural determination of long-chain diol-linked glycolipids.Bacteria of the genus Thermus have optimum growth temperatures of about 70°C and maximum growth temperatures of about 78 to 85°C (17, 30), and it has been suggested that the high proportion of glycolipids in their cell membranes contributes to this ability to grow at elevated temperatures, since the relative proportions of the major glycolipid increases concomitantly with growth temperature (20,24). Previous studies have shown that the polar lipids of these organisms usually comprise a major phospholipid, designated PL-2, a major glycolipid, designated GL-1, and in some strains or under certain culture conditions, a minor phospholipid, designated PL-1, and a minor glycolipid, designated 24,27). The structures of the phospholipids have not yet been elucidated, but the major glycolipid of most strains has been identified as a diglycosyl-(N-acyl)glycosaminyl-glycosyldiacylglycerol, which contains three hexose residues and one N-acylated hexosamine, giving a hexose/hexosamine/glycerol ratio of approximately 3:1:1 (2,18,19,24). On the other hand, GL-1 from Thermus aquaticus 15004 was recently shown to have N-acetylgalactosamine in place of the subterminal hexose residue, resulting in a hexose/ hexosamine/glycerol ratio of 2:2:1 (2).Thermus scotoductus X-1 (ATCC 27978) produces two colony types, designated t1 and t2 (27). The polar lipid composition of strain X-1 colony type t2 [X-1(t2)] is typical of most Thermus strains, consisting of a major phospholipid (PL-2), a major glycolipid (GL-1), and traces of a minor glycolipid (GL-2), whereas X-1(t1) has GL-2 as its major glycolipid and only trace amounts o...

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Does Thermus Represent Another Deep Eubacterial Branching?

Cited by 42 publications

References 25 publications

Phylogeny of Twenty Thermus Isolates Constructed from 16S rRNA Gene Sequence Data

Phylogeny of Twenty Thermus Isolates Constructed from 16S rRNA Gene Sequence Data

A conserved motif in S-layer proteins is involved in peptidoglycan binding in Thermus thermophilus

Characterization of novel long-chain 1,2-diols in Thermus species and demonstration that Thermus strains contain both glycerol-linked and diol-linked glycolipids

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