Reclassification of Treponema hyodysenteriae and Treponema innocens in a new genus, Serpula gen. nov., as Serpula hyodysenteriae comb. nov. and Serpula innocens comb. nov.

The intestinal anaerobic spirochetes Treponema hyodysenteriae B78T (T = type strain), B204, B169, and A-1, Treponema innocens B256T and 4/71, Treponema succinifaciens 6091T, and Treponema bryantii RUS-1T were compared by performing DNA-DNA reassociation experiments, sodium dodecyl sulfate-polyacrylamide gel electrophoresis of cell proteins, restriction endonuclease analysis of DNA, and 16S rRNA sequence analysis. DNA-DNA relative reassociation experiments in which the S1 nuclease method was used showed that T. hyodysenteriae B78T and B204 had 93% sequence homology with each other and approximately 40% sequence homology with T. innocens B256T and 4/71. Both T. hyodysenteriae B78T and T. innocens B256T exhibited negligible levels of DNA homology (less than or equal to 5%) with T. succinifaciens 6091T. The results of comparisons of protein electrophoretic profiles corroborated the DNA-DNA reassociation results. We found high levels of similarity (greater than or equal to 96%) in electrophoretic profiles among T. hyodysenteriae strains, moderate levels of similarity (43 to 49%) between T. hyodysenteriae and T. innocens, and no detectable similarity between the profiles of either T. hyodysenteriae or T. innocens and those of T. succinifaciens, T. bryantii, and Escherichia coli. Restriction endonuclease analysis of DNA was not useful in assessing genetic relationships since there was heterogeneity even between strains of T. hyodysenteriae. Partial 16S rRNA sequences of the intestinal spirochetes were determined by using a modified Sanger method and were compared in order to evaluate the phylogenetic relationships among these and other spirochetes.(ABSTRACT TRUNCATED AT 250 WORDS)     

中国吐鲁番两株产木聚糖酶的极端耐碱Bacillus halodurans的分类鉴定

通过生理生化实验、16S rDNA序列分析和同源性杂交,将分离到的XJU-1和XJU-80菌种进行了分类鉴定。XJU-1和XJU-80具有较宽的pH生长范围(分别是pH4·5 ~12·6和pH3·8 ~12·6) ,其G C mol%含量分别是40·5mol%和42·2mol%。16S rDNA序列分析和DNA-DNA同源杂交结果表明,XJU-1和XJU-80与Bacillushalodurans C-125和Bacillus halodurans DSM497T具有较高的同源性(99 %) ;两者之间也具有85 %的相关性,但其与Bacillus halodurans C-125和Bacillus halodurans DSM497T分别具有81·3 %和71·5 %的相关性。基于以上结果,将两株分离菌株分类为Bacillus halodurans的两个新品系。     

Bacillus beringensis sp. nov., a psychrotolerant bacterium isolated from the Bering Sea

Psychrotolerant Bacillus-like strains BR035(T) and BR011 were isolated from seawater of the Bering Sea and were characterized by means of a polyphasic approach. Phylogenetic analysis based on 16S rRNA gene sequences revealed that these strains were related to the members of the genus Bacillus and had the highest 16S rRNA gene sequence similarity with Bacillus korlensis ZLC-26(T). DNA-DNA hybridization experiments confirmed that strains BR035(T) and BR011 belonged to the same species and were distinct from their closest relatives. The cells were Gram-positive, rods, motile, spore-forming and psychrotolerant. The temperature range for growth was 4-42°C. The main respiratory quinone was MK-7. The polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, an unknown aminolipid and two unknown phospholipids. The major cellular fatty acids were iso-C15:0, anteiso-C15:0, iso-C14:0 and C16:1ω7c alcohol. The diagnostic diamino acid in the cell-wall peptidoglycan was meso-diaminopimelic acid. The genomic DNA G + C content was 37.6-37.8 mol%. On the basis of the phenotypic characteristics, phylogenetic analysis and DNA-DNA relatedness data, a novel species Bacillus beringensis is proposed and the type strain is BR035(T) (=CGMCC 1.9126(T)=DSM 22571(T)).     

Genetic relatedness of Trichoderma sect. Pachybasium species based on molecular approaches

Molecular approaches including internal transcribed spacer (ITS) sequences of ribosomal DNA, universal primer polymerase chain reaction (UP-PCR) fingerprinting, and DNA-DNA hybridization were used to study the genetic relatedness of species within Trichoderma sect. Pachybasium. In the analysis of ITS and 5.8S sequences of ribosomal DNA, parsimony analysis demonstrated that forty-one strains were distributed into five main groups supported by high bootstrap values. The species of Trichoderma sect. Pachybasium were clustered into groups I, II, and IV, with the strains of Trichoderma fasculatum and Trichoderma strictipile forming a separate branch, an independent group V. Some species within each group showed nearly identical sequence differences (fewer than 1-3 bp). UP-PCR and DNA-DNA hybridization were further used to clarify the genetic relatedness of these species with highly similar ITS sequences. Highly similar or identical UP-PCR profiles and high values of DNA complementarity (>70%) were observed among some species, Trichoderma hamatum and Trichoderma pubescens; Trichoderma croceum, Trichoderma polysporum and Trichoderma album, Trichoderma crassum and Trichoderma flavofuscum; and Trichoderma strictipile and Trichoderma fasciculatum. Although every species can be differentiated morphologically, the species showed highly similar molecular characteristics in the above cases, indicating that they could be conspecific. However, in some cases (Trithoderma longipile, T. crassum and T. flavofuscum; Trichoderma fertile and Trichoderma minutisporum; Trichoderma tomentosum, Trichoderma inhamatum and Trichoderma harzianum) there were discriminative patterns of UP-PCR and (or) low levels (<50%) of DNA-DNA hybridization; even their ITS sequences were similar, suggesting a closely phylogenetic relationship.     

Acinetobacter marinus sp. nov. and Acinetobacter seohaensis sp. nov., isolated from sea water of the Yellow Sea in Korea

Two Gram-negative, nonmotile, coccobacilli, SW-3T and SW-100T, were isolated from sea water of the Yellow Sea in Korea. Strains SW-3T and SW-100T contained ubiquinone-9 (Q-9) as the predominant respiratory lipoquinone and C18:1 omega9c and C16:0 as the major fatty acids. The DNA G+C contents of strains SW-3T and SW-100T were 44.1 mol% and 41.9 mol%, respectively. A neighbor-joining tree based on 16S rRNA gene sequences showed that the two isolates fell within the evolutionary radiation enclosed by the genus Acinetobacter. Strains SW-3T and SW-100T exhibited a 16S rRNA gene similarity value of 95.7% and a mean DNA-DNA relatedness level of 9.2%. Strain SW-3T exhibited 16S rRNA gene sequence similarity levels of 93.5-96.9% to the validly described Acinetobacter species and fifteen Acinetobacter genomic species. Strain SW-100T exhibited 16S rRNA gene sequence similarity levels of less than 97.0% to the other Acinetobacter species except Acinetobacter towneri DSM 14962T (98.0% similarity). Strains SW-3T and SW-100T exhibited mean levels of DNA-DNA relatedness of 7.3-16.7% to the type strains of some phylogenetically related Acinetobacter species. On the basis of phenotypic, phylogenetic, and genetic data, strains SW-3T and SW-100T were classified in the genus Acinetobacter as two distinct novel species, for which the names Acinetobacter marinus sp. nov. (type strain SW-3T=KCTC 12259T=DSM 16312T) and Acinetobacter seohaensis sp. nov. (type strain SW-100T=KCTC 12260T=DSM 16313T) are proposed, respectively.     

Detection of Treponema socranskii associated with human periodontitis by PCR.

A PCR technique was used to detect and identify Treponema socranskii associated with periodontitis. A species-specific forward primer was designed for a variable region within its 16S rRNA gene and was used in conjunction with a conserved reverse primer. This primer pair was tested for specificity against 44 oral bacterial strains. Sensitivity was determined using a serial dilution of T. socranskii cells. Amplification products were obtained from all T. socranskii strains tested, but not from other oral bacteria associated with periodontal disease. The detection limit of PCR was 5 T. socranskii cells per PCR. T. socranskii was detected by PCR in subgingival plaque and saliva samples from patients with periodontitis.     

Organization of the ribosomal RNA genes in Treponema phagedenis and Treponema pallidum.

The genomic DNA fragment which contains ribosomal RNA (rRNA) genes for Treponema phagedenis was cloned into bacteriophage vector lambda EMBL3. A restriction map of the fragment was constructed and the organization of the rRNA genes was determined. The fragment contained at least one copy of the 16S, 23S and 5S sequences and the genes are arranged in the order 16S-23S-5S. Southern hybridization using radiolabeled rRNA gene probes to genomic DNA from T. phagedenis strain Reiter and T. pallidum strain Nichols showed that these organisms have two radioactive fragments which hybridize to the probes in their genome. These results suggest that both pathogenic and non-pathogenic strains of Treponema may carry at least two sets of rRNA genes on their chromosomes.     

Reclassification of Methylobacterium chloromethanicum and Methylobacterium dichloromethanicum as later subjective synonyms of Methylobacterium extorquens and of Methylobacterium lusitanum as a later subjective synonym of Methylobacterium rhodesianum

Phylogenetic analysis based on 16S rDNA sequences was performed on all type strains of the 14 validly described Methylobacterium species to ascertain the genealogic relationships among these species. The results showed that type strains of Methylobacterium were divided into two monophyletic groups whose members were distinct species with sequence similarity values greater than 97.0% between any two of the members in the same group. Only M. organophilum JCM 2833(T) and ATCC 27886(T) were not divided into those two groups. In particular, strains of M. dichloromethanicum and M. chloromethanicum exhibited extremely high similarity values (99.9 and 100%, respectively) with the type strain of M. extorquens. To clarify the relationships among Methylobacterium species in more detail, phylogenetic analysis based on the 5' end hyper-variable region of 16S rDNA (HV region), ribotyping analysis, fatty acid analysis, G+C content analysis and DNA-DNA hybridization experiments was performed on 58 strains of Methylobacterium species. Results of the ribotyping analysis and the phylogenetic analysis based on HV region sequences indicated that many Methylobacterium strains, including M. 'organophilum' DSM 760(T), have been erroneously identified. The DNA G+C content of Methylobacterium strains were between 68.1 and 71.3%. Results of whole-cell fatty-acid profiles showed that all strains contained 18 : 1omega7c as the primary fatty acid component (82.8-90.1%), with 16 : 0 and 18 : 0 as minor components. M. dichloromethanicum DSM 6343(T), M. chloromethanicum NCIMB 13688(T), and M. extorquens IAM 12631(T) exhibited high DNA-DNA relatedness values between each other (69-80%). M. lusitanum NCIMB 13779(T) also showed a close relationship with M. rhodesianum DSM 5687(T) at DNA-DNA relatedness levels of 89-92%. According to these results, many Methylobacterium strains should be reclassified, with M. dichloromethanicum and M. chloromethanicum regarded as a synonym of M. extorquens, and M. lusitanum a synonym for M. rhodesianum.     

A novel protein-deamidating enzyme from Chryseobacterium proteolyticum sp. nov., a newly isolated bacterium from soil

A novel protein-deamidating enzyme, which has potential for industrial applications, was purified from the culture supernatant of Chryseobacterium proteolyticum strain 9670(T) isolated from rice field soil in Tsukuba, Japan. The deamidating activities on carboxybenzoxy (Cbz)-Gln-Gly and caseins and protease activity were produced synchronously by the isolate. Both deamidating activities were eluted as identical peaks separated from several proteases by phenyl-Sepharose chromatography of the culture supernatant. The enzyme catalyzed the deamidation of native caseins with no protease and transglutaminase activities. Phenotypic characterization and DNA analyses of the isolate were performed to determine its taxonomy. Physiological and biochemical characteristics, 16S rRNA gene sequence analysis, and DNA-DNA relatedness data indicated that the isolate should be placed as a new species belonging to the genus Chryseobacterium. The isolate showed no growth on MacConkey agar and produced acid from sucrose. The levels of DNA-DNA relatedness between the isolate and other related strains were less than 17%. The name Chryseobacterium proteolyticum is proposed for the new species; strain 9670 is the type strain (=FERM P-17664).     

Novel endophytes of rice form a taxonomically distinct subgroup of Serratia marcescens

Six endophytic strains isolated from surface-sterilized rice roots and stems of different rice varieties grown in the Philippines were characterized. They were analyzed by physiological and biochemical tests, SDS-PAGE of whole-cell protein patterns, DNA-DNA hybridization and 16S rDNA sequencing. SDS-PAGE of whole-cell patterns showed that the six isolates fell into two subgroups which were similar but not identical in protein patterns to S. marcescens. The phylogenetic analysis of 16S rDNA sequences of two representative strains IRBG 500 and IRBG 501 indicated that they were closely related to S. marcescens (more than 99% identity). Physiological and biochemical tests corroborated that the isolates were highly related to each other and to S. marcescens. In cluster analysis, all six isolates were clustered together at 93% similarity level and grouped closely with Serratia marcescens at 86% similarity level. DNA-DNA hybridization studies revealed that the isolates shared high similarity levels with S. marcescens (> or =86% DNA-DNA binding), indicating they belong to the same species. However, the isolates differed in several biochemical characteristics from the type strain. They produce urease and utilize urea and L(+) sorbose as a substrate, which is different from all known Serratia reference strains. These results suggest that the six endophytic isolates represent a novel, non-pigmented subgroup of S. marcescens.     

<Emphasis Type="Italic">Arthrobacter soli</Emphasis> sp. nov., a novel bacterium isolated from wastewater reservoir sediment

A novel Gram-positive bacterium, designated SYB2T, was isolated from wastewater reservoir sediment, and a polyphasic taxonomic study was conducted based on its morphological, physiological, and biochemical features, as well as the analysis of its 16S rRNA gene sequence. During the phylogenetic analysis of the strain SYB2T, results of a 16S rRNA gene sequence analysis placed this bacterium in the genus Arthrobacter within the family Micrococcaceae. SYB2T and Arthrobacter protophormiae ATCC 19271T, the most closely related species, both exhibited a 16S rRNA gene sequence similarity of 98.99%. The genomic DNA G+C content of the novel strain was found to be 62.0 mol%. The predominant fatty acid composition was anteiso-C15:0, anteiso-C17:0, iso-C16:0, and iso-C15:0. Analysis of 16S rRNA gene sequences and DNA-DNA relatedness, as well as physiological and biochemical tests, showed genotypic and phenotypic differences between strain SYB2T and other Arthrobacter species. The type strain of the novel species was identified as SYB2T (= KCTC 19291T= DSM 19449T).     

Streptococcus fryi sp. nov., a novel species with Lancefield group M antigens

The taxonomic characteristics of β-hemolytic streptococcal strains that reacted with Lancefield group M antisera were investigated. Group M streptococci have not been proposed as a species to date. Four strains of the group M streptococci isolated from dog were located within the pyogenic group of the genus Streptococcus on 16S rRNA gene-based phylogenetic analysis; the group M strains were located a short distance away from all other members of the group. The homology values of 16S rRNA gene sequences between group M strains and all other streptococci were<95.6%. Group M strains exhibited low levels of DNA-DNA homology to other streptococcal species. Some biochemical traits, such as β-galactosidase activity and acid production from glycogen, could distinguish these group M strains from other closely related species. Thus, these strains are proposed to constitute a new species -Streptococcus fryi sp. nov. The type strain is PAGU 653(T) (=NCTC 10235(T)=JCM 16387(T)).     

Gluconobacter sphaericus (Ameyama 1975) comb. nov., a brown pigment-producing acetic acid bacterium in the Alphaproteobacteria

Strain NBRC 12467(T )was examined genetically, phylogenetically, phenotypically, and chemotaxonomically. The DNA G+C content of the strain was 59.5 mol%. The strain represented low levels of DNA-DNA hybridization of 49-9% to the type strains of eight Gluconobacter species. The strain formed a cluster along with the type strains of G. albidus and G. kondonii in phylogenetic trees based on 16S rRNA gene sequences. In a phylogenetic tree based on 16S-23S rRNA gene ITS sequences, however, the strain formed an independent cluster from the type strains of the eight Gluconobacter species. Such phylogenetic relationships were supported by the calculated pair-wise 16S rRNA gene and 16S-23S rRNA gene ITS sequence similarities. The strain was distinguished from the type strains of the eight Gluconobacter species by 16S-23S rRNA gene ITS restriction analysis using five restriction endonucleases. The strain produced a water-soluble brown pigment and 2,5-diketo-D-gluconate from D-glucose, differing from the type strains of the eight Gluconobacter species, and acid from meso-erythritol very weakly, differing from the type strains of the remaining seven Gluconobacter species except for the type strain of G. roseus, but not from maltose, differing from the type strain of G. oxydans, and had Q-10. For the strain, which was once classified as G. oxydans subsp. sphaericus, Gluconobacter sphaericus (Ameyama 1975) comb. nov. is proposed. The type strain is NBRC 12467(T), which is also deposited as BCC 14448(T).     

Diverse endophytic nitrogen-fixing bacteria isolated from wild rice Oryza rufipogon and description of Phytobacter diazotrophicus gen. nov. sp. nov.

Twenty-three nitrogen-fixing bacteria were isolated from surface-sterilized stems and roots of wild rice Oryza rufipogon. Four clusters were defined among these bacteria by SDS-PAGE protein patterns and further confirmed by IS-PCR finger-printing analysis. Phylogenetic analysis of 16S rRNA gene sequences showed that the representative strains LS 8 and LS 18 of cluster II formed a monophyletic group sharing 94.0-97.3% similarities with defined enterobacterial species within the genera Salmonella, Citrobacter, Pantoea, Klebsiella, and Enterobacter. DNA-DNA hybridization, physiological, biochemical tests, and cell morphology also revealed that these strains could be differentiated from the related enterobacterial species. Based upon these results, we propose Phytobacter diazotrophicus gen. nov., sp. nov. to the bacterial group represented by strains LS 8 and LS 18. The type strain is LS 8(T) (=DSM 17806(T) = LMG 23328(T) = CGMCC 1.5339(T)). The DNA G+C content of strain LS 8(T) is 58.6 +/- 0.5 mol%.     

Isolation and characterization of a new type of aerobic,oxalic acid utilizing bacteria,and proposal of Oxalicibacterium flavum gen. nov., sp. nov

A mesophilic, aerobic oxalic acid utilizing yellow-pigmented bacterium has been isolated from litter of oxalate producing plants in the region of Izmir (Turkey). It is motile by means of 1-3 polar flagella. Optimal growth occurred between 25-30 degrees C at pH 6.9. The G+C content of DNA is 62-64 mol % (Tm). Based on its morphological and biochemical features the organism belongs to the genus Pseudomonas, but differs from all the previously described species. The taxonomic relationships among strains described as or previously tentatively assigned to the genus Pseudomonas were investigated using numerical classification, DNA base composition and DNA-DNA hybridization. 16S rDNA sequences were determined for the strain TA17. On the basis of 16S rDNA sequence comparisons, physiological and biochemical characteristics, it is proposed to classify TA17T in a new genus and species for which the name Oxalicibacterium flavum gen. nov., sp. nov. is proposed. The type strain is TA17T (= NEU98T, = LMG 21571T).     

Taxonomic characterization of <Emphasis Type="Italic">Haloferax</Emphasis> sp. ("<Emphasis Type="Italic">H. alicantei</Emphasis>") strain Aa 2.2: description of <Emphasis Type="Italic">Haloferax lucentensis</Emphasis> sp. nov.

An extremely halophilic archaeon, previously named as Haloferax sp. strain Aa 2.2 or "Haloferax alicantei" that has been extensively used for genetic studies with halobacteria, was taxonomically characterized by using phenotypic tests (including morphological, physiological, biochemical and nutritional features), DNA-DNA hybridization and 16S rRNA sequence phylogenetic analysis. This organism was isolated in 1986 by Torreblanca et al. from a pond of a Spanish saltern located in Alicante. The cells were pleomorphic, Gram negative and grew optimally at 25% NaCl. The polar lipid composition was similar to that of species of the genus Haloferax. The DNA G+C content of this strain was 64.5 mol%. Phylogenetic analysis based on 16S rRNA sequence comparison confirmed that this archaeon is a member of the genus Haloferax and was most closely related to Haloferax volcanii. DNA-DNA hybridization between strain Aa 2.2 and the type strain of all named species of the genus Haloferax revealed low levels of relatedness (25-2%), supporting the placement of this organism in a new species. On the basis of the phenotypic characteristics, molecular data and phylogenetic analysis we propose to name strain Aa 2.2 as a new species, Haloferax lucentensis sp. nov. The type strain is Aa 2.2 (=JCM 9276=NCIMB 13854=CIP 107410=DSM 14919=CECT 5871=CCM 7023).     

Assignment of<Emphasis Type="Italic"> Pseudomonas</Emphasis> sp. strain E-3 to<Emphasis Type="Italic"> Pseudomonas psychrophila</Emphasis> sp. nov., a new facultatively psychrophilic bacterium

A facultatively psychrophilic bacterium, previously described as Pseudomonas sp. strain E-3, has been reassigned by phenotypic characterization, chemotaxonomic analysis, DNA-DNA hybridization, and 16S rRNA gene phylogenetic analysis. The organism was a gram-negative, aerobic. straight rod with polar flagella. It was catalase positive and oxidase positive, able to grow at -1 degree C but not at 40 degree C, and produced acid from D-glucose under aerobic conditions. The major isoprenoid quinone was ubiquinone-9, and the DNA G + C content was 57.2 mol%. Phylogenetic analysis based on 16S rRNA gene sequencing indicated that the bacterium is a member of the genus Pseudomonas and was closest to Pseudomonas fragi. Determination of the DNA-DNA relatedness between strain E-3 and P. fragi revealed too low a level of homology (47.9%-51.3%) to identify them as the same species. On the basis of phenotypic characteristics, phylogenetic analysis, and DNA-DNA relatedness data, it is concluded that strain E-3 represents an individual species. Accordingly, the name Pseudomonas psychrophila is proposed. The type strain is E-3T (= JCM 10889).     

Novel Endophytes of Rice form a Taxonomically Distinct Subgroup of Serratia marcescens

Six endophytic strains isolated from surface-sterilized rice roots and stems of different rice varieties grown in the Philippines were characterized. They were analyzed by physiological and biochemical tests, SDS-PAGE of whole-cell protein patterns, DNA-DNA hybridization and 16S rDNA sequencing. SDS-PAGE of whole-cell patterns showed that the six isolates fell into two subgroups which were similar but not identical in protein patterns to S. marcescens. The phylogenetic analysis of 16S rDNA sequences of two representative strains IRBG 500 and IRBG 501 indicated that they were closely related to S. marcescens(more than 99% identity). Physiological and biochemical tests corroborated that the isolates were highly related to each other and to S. marcescens. In cluster analysis, all six isolates were clustered together at 93% similarity level and grouped closely with Serratia marcescens at 86% similarity level. DNA-DNA hybridization studies revealed that the isolates shared high similarity levels with S. marcescens(≥86% DNA-DNA binding), indicating they belong to the same species. However, the isolates differed in several biochemical characteristics from the type strain. They produce urease and utilize urea and L(+) sorbose as a substrate, which is different from all known Serratia reference strains. These results suggest that the six endophytic isolates represent a novel, non-pigmented subgroup of S. marcescens.     

How close is close: 16S rRNA sequence identity may not be sufficient to guarantee species identity.

16S rRNA (genes coding for rRNA) sequence comparisons were conducted with the following three psychrophilic strains: Bacillus globisporus W25T (T = type strain) and Bacillus psychrophilus W16AT, and W5. These strains exhibited more than 99.5% sequence identity and within experimental uncertainty could be regarded as identical. Their close taxonomic relationship was further documented by phenotypic similarities. In contrast, previously published DNA-DNA hybridization results have convincingly established that these strains do not belong to the same species if current standards are used. These results emphasize the important point that effective identity of 16S rRNA sequences is not necessarily a sufficient criterion to guarantee species identity. Thus, although 16S rRNA sequences can be used routinely to distinguish and establish relationships between genera and well-resolved species, very recently diverged species may not be recognizable.     

Exiguobacterium mexicanum sp. nov. and Exiguobacterium artemiae sp. nov., isolated from the brine shrimp Artemia franciscana

Two Gram-positive strains isolated from cysts of the brine shrimp Artemia franciscana were subjected to a polyphasic taxonomic analysis. Based on 16S rRNA gene sequence comparison and composition of isoprenoid quinones, peptidoglycan and fatty acids, these organisms are members of the genus Exiguobacterium. Both strains showed 95.9% 16S rRNA gene sequence similarity to one another. The 16S rRNA gene sequences of strain 8N(T) and 9AN(T) were 97.5% and 98.9% similar to those of Exiguobacterium aurantiacum DSM 6208(T) and Exiguobacterium undae DSM 14481(T), respectively. Based on differences in chemotaxonomic and physiological characteristics, results of DNA-DNA hybridization and automated riboprinting, two novel species of the genus Exiguobacterium are proposed, Exiguobacterium mexicanum sp. nov. (type strain 8N(T)=DSM 16483(T)=CIP 108859(T)) and Exiguobacterium artemiae sp. nov. (type strain 9AN(T)=DSM 16484(T)=CIP 108858(T)).