- Volume 54, Issue 5, 2004

The diversity of mucin-degrading bacteria in the human intestine was investigated by combining culture and 16S rRNA-dependent approaches. A dominant bacterium, strain MucT, was isolated by dilution to extinction of faeces in anaerobic medium containing gastric mucin as the sole carbon and nitrogen source. A pure culture was obtained using the anaerobic soft agar technique. Strain MucT was a Gram-negative, strictly anaerobic, non-motile, non-spore-forming, oval-shaped bacterium that could grow singly and in pairs. When grown on mucin medium, cells produced a capsule and were found to aggregate. Strain MucT could grow on a limited number of sugars, including N-acetylglucosamine, N-acetylgalactosamine and glucose, but only when a protein source was provided and with a lower growth rate and final density than on mucin. The G+C content of DNA from strain MucT was 47·6 mol%. 16S rRNA gene sequence analysis revealed that the isolate was part of the division Verrucomicrobia. The closest described relative of strain MucT was Verrucomicrobium spinosum (92 % sequence similarity). Remarkably, the 16S rRNA gene sequence of strain MucT showed 99 % similarity to three uncultured colonic bacteria. According to the data obtained in this work, strain MucT represents a novel bacterium belonging to a new genus in subdivision 1 of the Verrucomicrobia; the name Akkermansia muciniphila gen. nov., sp. nov. is proposed; the type strain is MucT (=ATCC BAA-835T=CIP 107961T).

Mycoplasma testudineum sp. nov., first cultured from the upper respiratory tract of a clinically ill tortoise (Gopherus agassizii) in the Mohave Desert, was distinguished from previously described mollicutes serologically and by 16S rRNA gene sequence comparisons. It lacks a cell wall; ferments glucose, mannose, lactose and sucrose; does not produce ‘film and spots’; does not hydrolyse arginine, aesculin or urea; is sensitive to digitonin; and lacks phosphatase activity. The organism causes chronic rhinitis and conjunctivitis of tortoises. The type strain of M. testudineum is BH29T (=ATCC 700618T=MCCM 03231T).

A novel thermophilic, microaerophilic, sulfur-reducing bacterium designated strain St55BT was isolated from a sulfide chimney in the hydrothermal field of Suiyo Seamount (Izu-Bonin Arc, Western Pacific). Cells of the isolate were rod-shaped and tended to form a chain-link circular structure (a rotund body) at exponential phase under good growth conditions. The isolate was a chemoheterotroph requiring yeast extract for growth. Although strain St55BT used oxygen as an electron acceptor, it could not form colonies in an oxygen concentration of more than 5 % (v/v). The isolate also used nitrate, nitrite or elemental sulfur in the absence of oxygen. A phylogenetic analysis based on the 16S rRNA gene sequence revealed that the isolate was closely related to Oceanithermus profundus, belonging to the phylum ‘Deinococcus–Thermus’ (sequence similarity 99·5 %). However, strain St55BT differed from O. profundus in terms of usage of electron donors, cellular fatty acid profile and DNA G+C content. In addition, a DNA–DNA hybridization test indicated low relatedness between the isolate and O. profundus. For the reasons given above, the name Oceanithermus desulfurans sp. nov. is proposed for strain St55BT (=NBRC 100063T=DSM 15757T).

Ninety-seven strains of budding bacteria originating from various aquatic habitats and morphologically resembling planctomycetes were investigated taxonomically. Taxonomic differentiation was based on DNA–DNA hybridization, physiological properties and chemotaxonomic tests. Nineteen hybridization groups, containing 79 of the tested strains, were established. Eighteen strains, however, did not fit into any of these groups. Rhodopirellula baltica gen. nov., sp. nov. is described, with strain SH 1T (=IFAM 1310T=DSM 10527T=NCIMB 13988T) as the type strain. Pirellula marina is transferred to the genus Blastopirellula gen. nov. as Blastopirellula marina comb. nov., with strain SH 106T (=IFAM 1313T=DSM 3645T=ATCC 49069T) as the type strain. An emended description of the genus Pirellula is also provided. Differentiation between R. baltica, B. marina and Pirellula staleyi was achieved by the integration of morphological, physiological, chemotaxonomic and genetic characteristics.

Morphological, biochemical and molecular genetic studies were carried out on an unknown non-spore-forming, Gram-negative, rod-shaped bacterium which was isolated from dog faeces. The bacterium grew under anaerobic conditions, was asaccharolytic, resistant to 20 % (v/v) bile and was oxidase- and urease-negative. Phylogenetic analysis based on comparative 16S rRNA gene sequencing showed that the unidentified bacterium clustered with Sutterella wadsworthensis, although a sequence divergence of >5 % indicated that the bacterium from dog faeces represented a previously unrecognized subline within the genus. On the basis of the presented findings, a novel species, Sutterella stercoricanis sp. nov., is described. The type strain of Sutterella stercoricanis is 5BAC4T (=CCUG 47620T=CIP 108024T).

The taxonomic position of four newly isolated marine, heterotrophic, gliding, Gram-negative, aerobic, pigmented, agarolytic bacteria was established. 16S rRNA gene sequence analysis indicated affiliation of the isolates to the genus Zobellia in the family Flavobacteriaceae. DNA–DNA hybridization experiments revealed that the strains studied represent three distinct and novel species, for which the names Zobellia amurskyensis sp. nov., Zobellia laminariae sp. nov. and Zobellia russellii sp. nov. are proposed, with KMM 3526T (=LMG 22069T=CCUG 47080T), KMM 3676T (=LMG 22070T=CCUG 47083T) and KMM 3677T (=LMG 22071T=CCUG 47084T), respectively, as the type strains.

Previously, a novel, fast-growing spirochaete was isolated from the hard tick Hyalomma aegyptium, which infests tortoises (Testudo graeca), by using Barbour–Stoenner–Kelly (BSK) II medium; the tick samples were taken from the Istanbul area in northwestern Turkey [ Güner et al. (2003) . Microbiology 149, 2539–2544]. Here is presented a detailed characterization of the spirochaete. Electron microscopy revealed that strain IST7T is morphologically similar to other spirochaetes of the genus Borrelia and possesses 15 to 16 flagellae that emerge from both polar regions. PFGE analysis revealed the genome to comprise a linear chromosome of approximately 1 Mb; two large linear plasmids of approximately 145 and 140 kb, and several small plasmids ranging from 50 to 20 kb in size were also found. The 16S rRNA gene sequence of this Borrelia isolate exhibited 99·4 to 99·8 % identity with other strains isolated from H. aegyptium and less than 99 % similarity with those of other Borrelia species. A phylogenetic tree, generated from 16S rRNA gene sequences, demonstrated that the spirochaete isolates from H. aegyptium clustered together and branched off from both Lyme-disease-related and relapsing-fever-associated Borrelia species. A single copy of the rrs gene was detected in the genome of strain IST7T by Southern hybridization. DNA–DNA hybridization results showed that strain IST7T was distinct from Lyme-disease-related Borrelia, Borrelia burgdorferi and the relapsing-fever-associated species Borrelia hermsii. The G+C content of strain IST7T is 30·0 mol%. From these genetic features, a novel Borrelia species, Borrelia turcica sp. nov., is proposed; the type strain is IST7T (=JCM 11958T=DSM 16138T).

Four marine heterotrophic, aerobic, pink-pigmented and non-motile bacterial strains were isolated from sea water and algae collected in the Sea of Japan. In a polyphasic taxonomic study, 16S rRNA gene sequence analysis indicated that the strains were phylogenetically highly related to Algoriphagus ratkowskyi LMG 21435T, a member of the phylum Bacteroidetes. Further phenotypic, chemotaxonomic and genomic analyses revealed that the strains represent three novel species of the genus Algoriphagus, for which the following names are proposed: Algoriphagus aquimarinus sp. nov., Algoriphagus chordae sp. nov. and Algoriphagus winogradskyi sp. nov., with type strains KMM 3958T (=LMG 21971T=CCUG 47101T), KMM 3957T (=LMG 21970T=CCUG 47095T) and KMM 3956T (=LMG 21969T=CCUG 47094T), respectively. The species Hongiella halophila Yi and Chun 2004 is transferred to the genus Algoriphagus as Algoriphagus halophilus comb. nov. because of its close phylogenetic relatedness to Algoriphagus species and analogous phenotypic and chemotaxonomic properties. The above-mentioned novel species descriptions and species reclassification justify emended descriptions of the genera Algoriphagus and Hongiella.

Two Gram-negative, non-motile, non-spore-forming, rod-shaped strains, SW-2T and SW-26, were isolated from sea water of the East Sea in Korea. These organisms grew optimally at 37 °C and in the presence of 2–3 % (w/v) NaCl. They did not grow without NaCl or in the presence of >9 % (w/v) NaCl. Strains SW-2T and SW-26 were characterized chemotaxonomically as having MK-7 as the predominant isoprenoid quinone and iso-C15 : 0 as the major fatty acid. The DNA G+C content of strains SW-2T and SW-26 was 43 mol%. A neighbour-joining tree based on 16S rRNA gene sequences showed that strains SW-2T and SW-26 fell within the Cytophaga–Flavobacterium–Bacteroides group and formed a coherent cluster with Hongiella species. Strains SW-2T and SW-26 showed a 16S rRNA gene sequence similarity value of 99·9 % and a mean DNA–DNA relatedness level of 87 % to each other. Levels of 16S rRNA gene sequence similarity between strains SW-2T and SW-26 and the type strains of two Hongiella species ranged from 94·2 to 96·6 %. On the basis of phenotypic and chemotaxonomic properties and phylogenetic distinctiveness, strains SW-2T and SW-26 should be placed in the genus Hongiella as members of a novel species, for which the name Hongiella marincola sp. nov. is proposed. The type strain is SW-2T (=KCTC 12180T=DSM 16067T).

Two novel bacteria, with an optimum growth temperature of approximately 60 °C, were isolated from Lu-shan hot springs in the central region of Taiwan. These isolates were aerobic, thermophilic, halotolerant, pink-pigmented, heterotrophic and resistant to gamma-radiation. Both pleomorphic, short, rod-shaped cells and coccoid cells were observed. Strains LS-286 (=ATCC BAA-452=BCRC 17198) and LS-293T (=ATCC BAA-406T=BCRC 17173T) represented a novel species of the genus Rubrobacter, according to a phylogenetic analysis of the 16S rRNA gene, DNA–DNA hybridization, biochemical features and fatty acid composition. The name Rubrobacter taiwanensis sp. nov. is proposed for this novel species, with LS-293T as the type strain.

Seven melanogenic Pseudoalteromonas distincta-like strains, KMM 3562T, KMM 3536, KMM 3537, KMM 3538, KMM 3539, KMM 3615 and KMM 3629, which expressed tyrosinases were isolated from sea-water samples collected from different locations in Amursky Bay (Sea of Japan, Pacific Ocean) and characterized to clarify their taxonomic position. By 16S rRNA gene sequence analysis, the bacteria were shown to belong to the genus Pseudoalteromonas. The G+C content of the DNAs of the strains was 41–43 mol%. The level of DNA similarity among these strains was conspecific (92–97 %), indicating that they represented a single genospecies. However, DNA from the strains isolated from sea water showed only 63–65 % genetic relatedness with the DNA of the type strain P. distincta. The novel organisms grew mainly between 4 and 30 °C, were neutrophilic and slightly halophilic (four strains had a narrow range of growth between 3 and 6 % NaCl, w/v), were haemolytic and cytotoxic and were able to degrade starch, gelatin and Tween 80. The predominant fatty acids, including 16 : 0, 16 : 1ω7, 17 : 1ω7 and 18 : 1ω7, were typical of the genus Pseudolateromonas. The phylogenetic, genetic and physiological properties of the seven strains placed them within a novel species, Pseudoalteromonas aliena sp. nov., the type strain of which is SW19T (=KMM 3562T=LMG 22059T).

A phylogenetic analysis of Bdellovibrio-and-like organisms (BALOs) was performed. It was based on the characterization of 71 strains and on all consequent 16S rRNA gene sequences available in databases, including clones identified by data-mining, totalling 120 strains from very varied biotopes. Amplified rDNA restriction analysis (ARDRA) accurately reflected the diversity and phylogenetic affiliation of BALOs, thereby providing an efficient screening tool. Extensive phylogenetic analysis of the 16S rRNA gene sequences revealed great diversity within the Bdellovibrio (>14 % divergence) and Bacteriovorax (>16 %) clades, which comprised nine and eight clusters, respectively, exhibiting more than 3 % intra-cluster divergence. The clades diverged by more than 20 %. The analysis of conserved 16S rRNA secondary structures showed that Bdellovibrio contained motifs atypical of the δ-Proteobacteria, suggesting that it is ancestral to Bacteriovorax. While none of the Bdellovibrio strains were of marine origin, Bacteriovorax included separate soil/freshwater and marine-specific groups. On the basis of their extensive diversity and the large distance separating the groups, it is proposed that Bacteriovorax starrii be placed into a new genus, Peredibacter gen. nov., with Peredibacter starrii A3.12T (=ATCC 15145T=NCCB 72004T) as its type strain. Also proposed is a redefinition of the Bdellovibrio and the Bacteriovorax–Peredibacter lineages as two different families, i.e. ‘Bdellovibrionaceae’ and a new family, Bacteriovoracaceae. Also, a re-evaluation of oligonucleotides targeting BALOs is presented, and the implications of the large diversity of these organisms and of their distribution in very different environments are discussed.

Strain F31T was isolated from meadow grass (Poa trivialis L.) sampled from the city park in Helsinki. Analysis of phenotypic and genotypic properties showed the strain to be related to the group of obligately methylotrophic non-methane utilizing bacteria (methylobacteria) with the ribulose monophosphate pathway of formaldehyde assimilation. Phylogenetic analysis showed the strain to be closely related to the genus Methylobacillus, and analysis of fatty acid composition confirmed this association. Thus, on the basis of its genotypic and phenotypic properties, the isolate is proposed as a novel species of the genus Methylobacillus, Methylobacillus pratensis sp. nov., with F31T as the type strain (=VKM B-2247T=NCIMB 13994T).

A novel mesophilic sulfur- and thiosulfate-oxidizing bacterium, strain 42BKTT, was isolated from the gas-bubbling sediment at the Iheya North hydrothermal system in the mid-Okinawa Trough, Japan. The isolate was a Gram-negative, non-motile and coccoid to oval-shaped bacterium. Growth was observed at 10–40 °C (optimum 28–30 °C) and in the pH range 5·0–9·0 (optimum 6·5–7·0). Strain 42BKTT grew chemolithoautotrophically with elemental sulfur or thiosulfate as a sole electron donor and oxygen (optimum 5 % in gas phase) or nitrate as an electron acceptor. The G+C content of the genomic DNA was 48·0 mol%. Phylogenetic analysis based on the 16S rRNA gene sequence indicated that the isolate belonged to the previously uncultivated Group F within the ε-Proteobacteria, which includes phylotypes of vent epibiont and environmental sequences from global deep-sea cold seep and hydrothermal vent fields. On the basis of the physiological and molecular characteristics of this isolate, the type species of a novel genus, Sulfurovum lithotrophicum gen. nov., sp. nov., is proposed. The type strain is 42BKTT (=ATCC BAA-797T=JCM 12117T).

A Gram-negative, yellow-pigmented, halophilic bacterial strain US6-1T, which degrades high-molecular-mass polycyclic aromatic hydrocarbons of two to five rings, was isolated from muddy sediment of Ulsan Bay, Republic of Korea. The 16S rRNA gene of the isolate showed high sequence similarity to Novosphingobium subarcticum (96·23 %) and Sphingopyxis alaskensis (96·18 %); however, the isolate formed a distinct phyletic line within the genus Novosphingobium. DNA–DNA relatedness between US6-1T and the closest strain N. subarcticum revealed that strain US6-1T was independent from this species. Isolate US6-1T had ubiquinone 10 and a DNA G+C ratio of 61·1 mol%. Major fatty acids were octadecanoic acid (18 : 1ω7), hexadecanoic acid (16 : 1ω7) and 2-hydroxy-myristic acid (14 : 0 2-OH). On the basis of polyphasic taxonomic evidence, strain US6-1T is proposed to represent a novel species in the genus Novosphingobium for which the name Novosphingobium pentaromativorans sp. nov. is proposed. The type strain is US6-1T (=KCTC 10454T=JCM 12182T).

Strain DS-1T is a small (0·8 μm in length and 0·2 μm in diameter) heterotrophic bacterium able to ω-oxygenate the commercial surfactant linear alkylbenzenesulfonate (LAS) and shorten the side chain by β-oxidation to yield sulfophenylcarboxylates. The morphotype is widespread in cultures able to utilize LAS, and a second organism with similar characteristics, strain AN-8, is now available. Utilization of LAS is concomitant with formation of a biofilm, and cells were non-motile. Many surfactants were utilized. The organisms also grew with acetate or octane, but required no biofilm and were motile. Analysis of the gene encoding 16S rRNA placed the organisms in the α-subclass of the Proteobacteria with a sequence divergence of >8 % from any species whose name has been validly published. 16S rRNA gene sequence comparison with entries in the GenBank database showed 98 % similarity to an α-protobacterial marine isolate, JP57: strain JP57 displayed the same morphotype as strain DS-1T, but it was unable to utilize surfactants or any single source of carbon tested. The lipid components of strains DS-1T and JP57 were virtually identical. The fatty acids contained ester- and putative amide-linked hydroxy fatty acids, in a combination that is currently unique in the α-Proteobacteria. The major respiratory quinone present in both strains was Q11. The polar lipids consisted of phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine and two unidentified aminolipids. Data on the 16S rRNA gene sequence and the lipid composition indicated that strains DS-1T and JP57 should be placed in a new genus, for which the name Parvibaculum is proposed. The differences between these strains, supported by DNA hybridizations, lead to the conclusion that strain DS-1T (=DSM 13023T=NCIMB 13966T) is the type strain of a species in the genus Parvibaculum, for which the name Parvibaculum lavamentivorans gen. nov., sp. nov. is proposed.