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1.
Several barophilic Shewanella species have been isolated from deep-sea sediments at depths of 2,485– 6,499 m. From the results of taxonomic studies, all
of these isolates have been identified as strains of Shewanella benthica except for strain DSS12. Strain DSS12 is a member of a novel, moderately barophilic Shewanella species isolated from the Ryukyu Trench at a depth of 5,110 m. On Marine Agar 2216 plates, this organism produced a violet
pigment, whereas the colonies of other isolates (S. benthica) were rose-colored. Phylogenetic analysis based on 16 S ribosomal RNA gene sequences showed that strain DSS12 represents
a separate lineage within the genus Shewanella that is closely related to S. benthica and particularly to the members of the Shewanella barophiles branch. The temperature range for growth and some of the biochemical characteristics indicate that strain DSS12
differs from other Shewanella species. Furthermore, strain DSS12 displayed a low level of DNA similarity to the Shewanella type strains. Based on these differences, it is proposed that strain DSS12 represents a new deep-sea Shewanella species. The name Shewanella violacea (JCM 10179) is proposed.
Received: 15 May 1998 / Accepted: 15 July 1998 相似文献
2.
Isolation of extremophiles with the detection and retrieval of<Emphasis Type="Italic"> Shewanella</Emphasis> strains in deep-sea sediments from the west Pacific 总被引:10,自引:0,他引:10
Tests to detect the presence of piezophilic Shewanella strains in the deep-sea sediments of the west, mid- and east Pacific at different depths were done by amplification of previously identified pressure-regulated operons (ORF1,2 and ORF3). The operon fragments were detected in all the deep-sea sediment samples, indicating the broad presence of piezophilic deep-sea Shewanella species or related species in the deep-sea sediments across the Pacific. Extremophiles were isolated from the deep-sea sediment of the west Pacific under atmospheric pressure. Two psychrophilic/psychrotrophic strains, WP2 and WP3, were assigned to the Shewanella genus as determined by their 16S rDNA sequences. WP2 and WP3 were both capable of amplifying pressure-regulated operons; the sequences of the pressure-regulated operons of WP2 and WP3 share high identity between each other, but have more differences from those of S. benthica and S. violacea. The major fatty acids of WP2 and WP3 are 3OH-i-13:0, 14:0, i-15:0, 16:0, 16:1, 18:1, and 20:5. Combined phenotypic analysis, 16S rDNA sequences, and DNA–DNA hybridization results suggest that WP2 and WP3 are two new deep-sea Shewanella species.Communicated by K. Horikoshi 相似文献
3.
The molecular biology of barophilic bacteria 总被引:3,自引:1,他引:3
Many microorganisms from the deep-sea display high-pressure-adapted — also described as barophilic or piezophilic — growth
characteristics. Phylogenetic studies have revealed that a large proportion of the barophilic bacteria currently in culture
collections belong to a distinct subgroup of the genus Shewanella, referred to as the “barophile branch.“ Many of the basic properties of barophiles that enable their survival at extremes
of pressure remain to be elucidated. However, several genes whose expression is regulated by pressure, or which appear to
be critical to baroadaptation, have been uncovered. One such operon, whose presence appears to be restricted to the “barophile
branch,” has been identifed in DNA samples obtained from sediments recovered in the deepest ocean trench. In the case of another
set of pressure-regulated genes, regulatory elements required for pressure signaling have been uncovered. The nature and regulation
of these genes is discussed.
Received: February 19, 1997 / Accepted: March 3, 1997 相似文献
4.
Ikegami A Nakasone K Fujita M Fujii S Kato C Usami R Horikoshi K 《Biochimica et biophysica acta》2000,1491(1-3):315-320
We have recently reported that a sigma(54)-like factor recognizes a DNA element, designated as region A, upstream of a pressure-regulated operon in piezophilic Shewanella violacea strain DSS12 (Nakasone et al., FEMS Microbiology Lett. 176 (1999) 351-356). In this study, we isolated and characterized the rpoN gene of this piezophilic bacterium. The rpoN gene was found to encode a putative protein consisting of 492 amino acid residues with a predicted molecular mass of 55359 Da. Significant homology was evident comparing the rpoN sequence of S. violacea with that of Escherichia coli (62.8% identity), Vibrio anguillarum (61.7% identity) and Pseudomonas putida (57.0% identity). The DNA-binding domain at the C-terminus of sigma(54) is well conserved in the case of the S. violacea rpoN gene product and the helix-turn-helix motif and the RpoN box are also present. In addition, the conserved glutamine-rich domain is present at the N-terminus. sigma(54) in S. violacea was expressed at a relatively constant level under various growth conditions as determined by both primer extension and Western blotting analyses. By means of a recombinant plasmid, a hexahistidine-tagged derivative of the sigma(54) from strain DSS12 was overexpressed in Escherichia coli and purified to near homogeneity. An electrophoretic mobility shift assay demonstrated that the purified sigma(54) protein specifically recognizes region A in the above-mentioned pressure-regulated operon. 相似文献
5.
Mohammad Hassan Qureshi Chiaki Kato Koki Horikoshi 《Extremophiles : life under extreme conditions》1998,2(2):93-99
We investigated for the first time the respiratory chain system of a deep-sea barophilic bacterium, Shewanella sp. strain DB-172F. A membrane-bound ccb-type quinol oxidase, from cells grown at 60 MPa pressure, was purified to an electrophoretically homogeneous state. The purified
enzyme complex consisted of four kinds of subunits with molecular masses of 98, 66, 18.5, and 15 kDa, and it contained 0.96
mol of protoheme and 1.95 mol of covalently bound heme c per mol of enzyme. Only protoheme in the enzyme reacted with CO and CN−, and the catalytic activity of the enzyme was 50% inhibited by 4 μM CN−. The isoelectric point of the native enzyme complex was determined to be 5.0. This enzyme was specifically induced only under
conditions of elevated hydrostatic pressure, and high levels were expressed in cells grown at 60 MPa. The membranes isolated
from cells grown at atmospheric pressure (0.1 MPa) exhibited high levels of both cytochrome c oxidase and N,N,N′,N′-tetramethyl-p-phenylenediamine (TMPDH2)-oxidase activity. These results suggest the presence of two kinds of respiratory chains regulated
in response to pressure in the deep-sea bacterium DB-172F.
Received: November 25, 1997 / Accepted: December 25, 1997 相似文献
6.
J B Perkins A Sloma T Hermann K Theriault E Zachgo T Erdenberger N Hannett N P Chatterjee V Williams II GA Rufo Jr R Hatch J Pero 《Journal of industrial microbiology & biotechnology》1999,22(1):8-18
Recombinant DNA engineering was combined with mutant selection and fermentation improvement to develop a strain of Bacillus subtilis that produces commercially attractive levels of riboflavin. The B. subtilis riboflavin production strain contains multiple copies of a modified B. subtilis riboflavin biosynthetic operon (rib operon) integrated at two different sites in the B. subtilis chromosome. The modified rib operons are expressed constitutively from strong phage promoters located at the 5′ end and in an internal region of the operon.
The engineered strain also contains purine analog-resistant mutations designed to deregulate the purine pathway (GTP is the
precursor for riboflavin), and a riboflavin analog-resistant mutation in ribC that deregulates the riboflavin biosynthetic pathway.
Received 22 June 1998/ Accepted in revised form 6 November 1998 相似文献
7.
M. Summit Brad Scott Kirk Nielson Eric Mathur John Baross 《Extremophiles : life under extreme conditions》1998,2(3):339-345
DNA polymerases derived from three thermophilic microorganisms, Pyrococcus strain ES4, Pyrococcus furiosus, and Thermus aquaticus, were stabilized in vitro by hydrostatic pressure at denaturing temperatures of 111°C, 107.5°C, and 100°C (respectively). Inactivation rates, as determined
by enzyme activity measurements, were measured at 3, 45, and 89 MPa. Half-lives of P. strain ES4, P. furiosus, and T. aquaticus DNA polymerases increased from 5.0, 6.9, and 5.2 minutes (respectively) at 3 MPa to 12, 36, and 13 minutes (respectively)
at 45 MPa. A pressure of 89 MPa further increased the half-lives of P. strain ES4 and T. aquaticus DNA polymerases to 26 and 39 minutes, while the half-life of P. furiosus DNA polymerase did not increase significantly from that at 45 MPa. The decay constant for P. strain ES4 and T. aquaticus polymerases decreased exponentially with increasing pressure, reflecting an observed change in volume for enzyme inactivation
of 61 and 73 cm3/mol, respectively. Stabilization by pressure may result from pressure effects on thermal unfolding or pressure retardation
of unimolecular inactivation of the unfolded state. Regardless of the mechanism, pressure stabilization of proteins could
explain the previously observed extension of the maximum temperature for survival of P. strain ES4 and increase the survival of thermophiles in thermally variable deep-sea environments such as hydrothermal vents.
Received: September 12, 1997 / Accepted: February 24, 1998 相似文献
8.
A Gram-negative, motile and rod-shaped bacterial strain, designated S7-3T, was isolated from a tidal flat sediment at Saemankum on the western coast of Korea. Phylogenetic analyses based on 16S rRNA gene and gyrB sequences showed that strain S7-3T belonged to the genus Shewanella, clustering with Shewanella decolorationis S12T. Strain S7-3T exhibited 98.8 % 16S rRNA gene sequence similarity and 96.8 % gyrB sequence similarity to S. decolorationis S12T, respectively. The 16S rRNA gene sequence similarity values between strain S7-3T and other members of the genus Shewanella were in the range of 93.0–98.0 %. Strain S7-3T contained simultaneously both menaquinones (MK) and ubiquinones (Q); the predominant menaquinone was MK-7 and the predominant ubiquinones were Q-7 and Q-8. The fatty acid profiles of strain S7-3T and S. decolorationis JCM 21555T were similar; major components were C17:1 ω8c, iso-C15:0 and iso-C15:0 2-OH and/or C16:1 ω7c. The DNA G+C content of strain S7-3T was 51.8 mol% and its mean DNA–DNA relatedness value with S. decolorationis JCM 21555T was 43 %. Differential phenotypic properties of strain S7-3T, together with the phylogenetic and genetic distinctiveness, revealed that this strain is distinguishable from recognized Shewanella species. On the basis of the data presented, strain S7-3T is considered to represent a novel Shewanella species, for which the name Shewanella seohaensis sp. nov. is proposed. The type strain is S7-3T (=KCTC 23556T = CCUG 60900T). 相似文献
9.
Marteinsson VT Birrien JL Raguénès G da Costa MS Prieur D 《Extremophiles : life under extreme conditions》1999,3(4):247-251
We examined a single, non-spore-forming, aerobic, thermophilic strain that was isolated from a deep-sea hydrothermal vent
in the Guaymas Basin at a depth of 2000 m and initially placed in a phenetic group with Thermus scotoductus (X-1). We identified this deep-sea isolate as a new strain belonging to Thermus thermophilus using several parameters. DNA–DNA hybridization under stringent conditions showed 74% similarity between the deep-sea isolate
and T. thermophilus HB-8T (T = type strain). Phenotypic characteristics, such as the utilization of carbon sources, hydrolysis of different compounds,
and antibiotic sensitivity were identical in the two strains. The polar lipids composition showed that strain Gy1211 belonged
to the genus Thermus. The fatty acids composition indicated that this strain was related to the marine T. thermophilus strain isolated from the Azores. The new isolate T. thermophilus strain Gy1211 grew optimally at 75°C, pH 8.0, and 2% NaCl. A hydrostatic pressure of 20 MPa, similar to the in situ hydrostatic
pressure of the deep-sea vent from which the strain was isolated, had no effect on growth. Strain HB-8T, however, showed slower growth under these conditions.
Received: November 26, 1997 / Accepted: May 20, 1999 相似文献
10.
Molecular analyses of the sediment of the 11000-m deep Mariana Trench 总被引:10,自引:1,他引:10
Chiaki Kato Lina Li Jin Tamaoka Koki Horikoshi 《Extremophiles : life under extreme conditions》1997,1(3):117-123
We have obtained sediment samples from the world's deepest sea-bottom, the Mariana Trench challenger point at a depth of
10 898 m, using the new unmanned submersible Kaiko. DNA was extracted from the sediment, and DNA fragments encoding several prokaryotic ribosomal RNA small-subunit sequences
and pressure-regulated gene clusters, typically identifed in deep-sea adapted bacteria, were amplifed by the polymerase chain
reaction. From the sequencing results, at least two kinds of bacterial 16S rRNAs closely related to those of the genus Pseudomonas and deep-sea adapted marine bacteria, and archaeal 16S rRNAs related to that of a planktonic marine archaeon were identifed.
The sequences of the amplifed pressure-regulated clusters were more similar to those of deep-sea barophilic bacteria than
those of barotolerant bacteria. These results suggest that deep-sea adapted barophilic bacteria, planktonic marine archaea,
and some of the world's most widespread bacteria (the genus Pseudomonas) coexist on the world's deepest sea-bottom.
Received: October 10, 1996 / Accepted: March 3, 1997 相似文献
11.
Kim KK Kim YO Park S Kang SJ Nam BH Kim DN Oh TK Yoon JH 《Journal of microbiology (Seoul, Korea)》2011,49(3):381-386
A Gram-staining-negative, motile, non-spore-forming and rod-shaped bacterial strain, 20-23RT, was isolated from intestine of bensasi goatfish, Upeneus bensasi, and its taxonomic position was investigated by using a polyphasic study. Phylogenetic analyses based on 16S rRNA gene sequences
revealed that strain 20-23RT belonged to the genus Shewanella. Strain 20-23RT exhibited 16S rRNA gene sequence similarity values of 99.5, 99.2, and 97.5% to Shewanella algae ATCC 51192T, Shewanella haliotis DW01T, and Shewanella chilikensis JC5T, respectively. Strain 20-23RT exhibited 93.1–96.0% 16S rRNA gene sequence similarity to the other Shewanella species. It also exhibited 98.3–98.4% gyrB sequence similarity to the type strains of S. algae and S. haliotis. Strain 20-23RT contained simultaneously both menaquinones and ubiquinones; the predominant menaquinone was MK-7 and the predominant ubiquinones
were Q-8 and Q-7. The fatty acid profiles of strain 20–23RT, S. algae KCTC 22552T and S. haliotis KCTC 12896T were similar; major components were iso-C15:0, C16:0, C16:1 ω7c and/or iso-C15:0 2-OH and C17:1 ω8c. The DNA G+C content of strain 20-23RT was 53.9 mol%. Differential phenotypic properties and genetic distinctiveness of strain 20–23RT, together with the phylogenetic distinctiveness, revealed that this strain is distinguishable from recognized Shewanella species. On the basis of the data presented, strain 20-23RT represents a novel species of the genus Shewanella, for which the name Shewanella upenei sp. nov. is proposed. The type strain is 20–23RT (=KCTC 22806T =CCUG 58400T). 相似文献
12.
13.
T. Potrawfke T.-H. Löhnert K. N. Timmis R.-M. Wittich 《Applied microbiology and biotechnology》1998,50(4):440-446
The biphenyl-mineralizing bacterium Burkholderia sp. strain LB400 also utilized 3-chloro-, 4-chloro-, 2,3′-dichloro- and 2,4′-dichlorobiphenyl for growth. By the attack of the initial enzyme a chlorine was eliminated dioxygenolytically
from position 2 of one of the aromatic rings when hydrogens of both were substituted by chlorine. The strain mineralized 3-chloro-
and 2,3′-dichlorobiphenyl via the central intermediate 3-chlorobenzoate through its chlorocatechol pathway enzymes, but excreted
stoichiometric amounts of 4-chlorobenzoate from 4-chloro- and 2,4′-dichlorobiphenyl. These two compounds were mineralized by a co-culture of strain LB400 and a derivative of the (methyl-)
benzoate-degrading strain Pseudomonas putida mt-2 (TOL). The complete degradation was achieved upon transfer of a cluster of at least five genes, encoding the regulated
chlorocatechol pathway operon, from strain LB400 to strain mt-2. This transfer was demonstrated by the polymerase chain reaction.
Received: 15 April 1998 / Received revision: 12 June 1998 / Accepted: 19 June 1998 相似文献
14.
《Bioscience, biotechnology, and biochemistry》2013,77(7):1522-1528
The facultative piezophile Shewanella violacea DSS12 is known to have respiratory components that alter under the influence of hydrostatic pressure during growth, suggesting that its respiratory system is adapted to high pressure. We analyzed the expression of the genes encoding terminal oxidases and some respiratory components of DSS12 under various growth conditions. The expression of some of the genes during growth was regulated by both the O2 concentration and hydrostatic pressure. Additionally, the activities of cytochrome c oxidase and quinol oxidase of the membrane fraction of DSS12 grown under various conditions were measured under high pressure. The piezotolerance of cytochrome c oxidase activity was dependent on the O2 concentration during growth, while that of quinol oxidase was influenced by pressure during growth. The activity of quinol oxidase was more piezotolerant than that of cytochrome c oxidase under all growth conditions. Even in the membranes of the non-piezophile Shewanella amazonensis, quinol oxidase was more piezotolerant than cytochrome c oxidase, although both were highly piezosensitive as compared to the activities in DSS12. By phylogenetic analysis, piezophile-specific cytochrome c oxidase, which is also found in the genome of DSS12, was identified in piezophilic Shewanella and related genera. Our observations suggest that DSS12 constitutively expresses piezotolerant respiratory terminal oxidases, and that lower O2 concentrations and higher hydrostatic pressures induce higher piezotolerance in both types of terminal oxidases. Quinol oxidase might be the dominant terminal oxidase in high-pressure environments, while cytochrome c oxidase might also contribute. These features should contribute to adaptation of DSS12 in deep-sea environments. 相似文献
15.
A Gram-negative, facultatively anaerobic, non-motile and rod-shaped bacterial strain, designated SMK1-12T, was isolated from a tidal flat sediment on the western coast of Korea. Phylogenetic analyses based on 16S rRNA and gyrB gene sequences showed that strain SMK1-12T belonged to the genus Shewanella, clustering with the type strain of Shewanella amazonensis. Strain SMK1-12T exhibited the highest 16S rRNA gene sequence similarity value (97.0 %) and the highest gyrB sequence similarity value (87.8 %) to S. amazonensis SB2BT, respectively. Strain SMK1-12T contained simultaneously both menaquinones and ubiquinones; the predominant menaquinone was MK-7 and the predominant ubiquinones were Q-7 and Q-8. The major fatty acids (>10 % of the total fatty acids) detected in strain SMK1-12T were the MIDI system summed feature 3 (iso-C15:0 2-OH and/or C16:1 ω7c), iso-C15:0, C17:1 ω8c and C16:0. The DNA G+C content of strain SMK1-12T was 58.0 mol% and its mean DNA–DNA relatedness value with S. amazonensis ATCC 700329T was 15 ± 4.6 %. Differential phenotypic properties, together with the phylogenetic and genetic distinctiveness, revealed that strain SMK1-12T is distinguishable from recognized Shewanella species. On the basis of the data presented, strain SMK1-12T is considered to represent a novel Shewanella species, for which the name Shewanella litorisediminis sp. nov. is proposed. The type strain is SMK1-12T (=KCTC 23961T = CCUG 62411T). 相似文献
16.
Sotaro Fujii Misa Masanari-Fujii Shinya Kobayashi Chiaki Kato Masayoshi Nishiyama Yoshie Harada 《Bioscience, biotechnology, and biochemistry》2018,82(5):792-799
Two cytochromes c5 (SBcytc and SVcytc) have been derived from Shewanella living in the deep-sea, which is a high pressure environment, so it could be that these proteins are more stable at high pressure than at atmospheric pressure, 0.1 MPa. This study, however, revealed that SBcytc and SVcytc were more stable at 0.1 MPa than at higher pressure. In addition, at 0.1–150 MPa, the stability of SBcytc and SVcytc was higher than that of homologues from atmospheric-pressure Shewanella, which was due to hydrogen bond formation with the heme in the former two proteins. This study further revealed that cytochrome c551 (PMcytc) of deep-sea Pseudomonas was more stable than a homologue of atmospheric-pressure Pseudomonas aeruginosa, and that specific hydrogen bond formation with the heme also occurred in the former. Although SBcytc and SVcytc, and PMcytc are phylogenetically very distant, these deep-sea cytochromes c are commonly stabilized through hydrogen bond formation. 相似文献
17.
A variant of Saccharomyces cerevisiae pep4 strain 20B12, with improved oligotrophic proliferation, cell survival and secretion of heterologous mouse α-amylase, is described.
Previously we reported a procedure to enrich NI transformants that are not inhibited by cytotoxic expression of hepatitis
B virus surface antigen in the secretion pathway of the protease-A-deficient (pep4) strain. To use the NI cells as a host for heterologous expression, we tried to amend the introduced pYAS/12S vector and
obtain a host strain, NI-C, with stable NI phenotype and trp1 marker restored. Southern analysis of genomic DNA of NI-C suggested that the original pYAS/12S was abnormally rearranged
and not completely corrected. Further assay showed that the viability and mitotic ability of the NI-C strain were increased.
While using the NI-C strain as host for plasmid transformation and heterologous expression of mouse α-amylase, we observed
that transformed colonies grew more quickly and secreted more α-amylase than general yeast strains. A further test showed
that the NI-C strain was able to use mouse α-amylase as a positive selection marker to form transformed colonies on nitrogen-starved
plates that contain starch as the sole carbon source. The results imply that the NI-C variant is an improved pep4 strain that can be used for heterologous expression and for the development of new selective markers in the yeast transformation
system.
Received: 7 January 1998 / Received last revision: 7 September 1998 / Accepted: 11 October 1998 相似文献
18.
Thebgl operon ofEscherichia coli, which encodes the genes necessary for transport and catabolism of β-glucosides, is silent in wild-type cells and is activated
by the transposition of IS elements. The silent form of the operon appears to be the stable state. We isolated Bgl- revertants of an activated strain after growth under nonselective conditions to understand whether activation of the cryptic
operon by IS elements is reversible. Genetic and molecular analyses revealed that a majority of revertants carry deletions
of thebgl structural genes, indicating that an irreversible alteration has occurred in the operon. Implications of these results for
the evolution and maintenance of cryptic genes are discussed. [Yakkundi A., Moorthy S. and Mahadevan S. 1998 Reversion of
anE. coli strain carrying an IS1-activatedbgl operon under nonselective conditions is predominantly due to deletions within the structural genes.J. Genet.
77, 21–26] 相似文献
19.
Murakami C Ohmae E Tate S Gekko K Nakasone K Kato C 《Extremophiles : life under extreme conditions》2011,15(2):165-175
To examine whether dihydrofolate reductase (DHFR) from deep-sea bacteria has undergone molecular evolution to adapt to high-pressure
environments, we cloned eight DHFRs from Shewanella species living in deep-sea and ambient atmospheric-pressure environments, and subsequently purified six proteins to compare
their structures, stabilities, and functions. The DHFRs showed 74–90% identity in primary structure to DHFR from S. violacea, but only 55% identity to DHFR from Escherichia coli (ecDHFR). Far-ultraviolet circular dichroism and fluorescence spectra suggested that the secondary and tertiary structures
of these DHFRs were similar. In addition, no significant differences were found in structural stability as monitored by urea-induced
unfolding and the kinetic parameters, K
m and k
cat; although the DHFRs from Shewanella species were less stable and more active (2- to 4-fold increases in k
cat/K
m) than ecDHFR. Interestingly, the pressure effects on enzyme activity revealed that DHFRs from ambient-atmospheric species
are not necessarily incompatible with high pressure, and DHFRs from deep-sea species are not necessarily tolerant of high
pressure. These results suggest that the DHFR molecule itself has not evolved to adapt to high-pressure environments, but
rather, those Shewanella species with enzymes capable of retaining functional activity under high pressure migrated into the deep-sea. 相似文献
20.
Grote R Li L Tamaoka J Kato C Horikoshi K Antranikian G 《Extremophiles : life under extreme conditions》1999,3(1):55-62
A novel coccoid-shaped, hyperthermophilic, anaerobic archaeon, strain RG-20, was isolated from a deep-sea hydrothermal vent
fluid sample taken at 1394-m depth at the Mid-Okinawa Trough (27°32.7′N, 126°58.5′E). Cells of this isolate occur singly or
in pairs and are about 0.8 to 2 μm in diameter. Growth was observed at temperatures between 50° and 93°C, with an optimum
at 85°C. The pH range for growth is 5.0–9.0, with an optimum around 7.0. Strain RG-20 requires 1%–4% of NaCl for growth, and
cell lysis occurs at concentrations below 1%. The newly isolated strain grows preferentially in the presence of elemental
sulfur on proteinaceous substrates such as yeast extract, peptone, or tryptone, and no growth was observed on carbohydrates,
carboxylic acids, alcohols, or lipids. This microorganism is resistant to streptomycin, chloramphenicol, ampicillin, and kanamycin
at concentrations up to 150 μg/ml, but is susceptible to rifampicin. Analysis of the hydrolyzed core lipids by thin-layer
chromatography (TLC) revealed the presence of archaeol and caldarchaeol. The mol% G+C content of the DNA is 55.8. Partial
sequencing of the 16S rDNA indicates that strain RG-20 belongs to the genus Thermococcus. Considering these data and on the basis of the results from DNA-DNA hybridization studies, we propose that this strain should
be classified as a new species named Thermococcus siculi (si′cu.li. L. gen. n. siculi, of the deep-sea [siculum, deep-sea in literature of Ovid], referring to the location of the sample site, a deep-sea hydrothermal vent). The type strain
is isolate RG-20 (DSM No. 12349).
Received: May 11, 1998 / Accepted: July 24, 1998 相似文献