Pseudoalteromonas ruthenica sp. nov., isolated from marine invertebrates

On the basis of phenotypic and genotypic characteristics and analysis of 165 rRNA sequences, a novel species belonging to the genus Pseudoalteromonas is described. Two pale-orange-pigmented strains, KMM 300T and KMM 290, isolated respectively from a mussel, Crenomytilus grayanus, and a scallop, Patinopecten yessoensis, are marine, gram-negative, aerobic, rod-shaped bacteria that produce a number of antimicrobial compounds. The strains are able to degrade gelatin, elastin, starch, DNA and Tween 80. Chitin and agar are not degraded. The isolates from marine invertebrates grew at NaCl concentrations of 1-9% and a temperature range of 10-35 degrees C and did not utilize most of the wide range of carbohydrates tested, with the exception of D-glucose, cellobiose and sucrose. The DNA G+C content was 48.4-48.9 mol%. The level of DNA homology of the two strains was 98%. DNA from the strains isolated from marine invertebrates showed 5-15% genetic relatedness to the DNA of other type strains of the genus Pseudoalteromonas. 16S rRNA analysis indicated a clear affiliation of the novel bacteria to other species of the genus. The strains are assigned to a novel species, Pseudomonas ruthenica sp. nov., with the type strain KMM 300T (= LMG 19699T = CIP 106857T).

Pseudoalteromonas issachenkonii sp. nov., a bacterium that degrades the thallus of the brown alga Fucus evanescens

Eleven non-pigmented strains of gram-negative, aerobic, marine bacteria with polar flagella were isolated from the thallus of the brown alga Fucus evanescens collected in the Kraternaya Bight of the Kurile Islands in the Pacific Ocean. These organisms were conspecific and exhibited high levels of genetic relatedness (up to 91%). The G+C contents of the DNAs of these strains were 42.9-43.3 mol%. These halophilic bacteria had bacteriolytic, proteolytic and haemolytic activities and degraded algal polysaccharides, synthesizing a number of glycoside hydrolases (fucoidanases, laminaranases, alginases, agarases, pullulanases, beta-glucosidases, beta-galactosidases, beta-N-acetylglucosaminidases and beta-xylosidases). By 16S rDNA analysis, the bacteria were shown to belong to the genus Pseudoalteromonas, a member of the gamma-subclass of the Proteobacteria. DNA from the strains isolated from the brown alga showed 27-54% genetic relatedness with respect to DNAs of other type strains of the genus Pseudoalteromonas. The phenotypic characteristics, together with the genetic evidence, indicate that this group of epiphytic bacteria represents a distinct species, Pseudoalteromonas issachenkonii sp. nov., for which the type strain is KMM 3549T (= LMG 19697T = CIP 106858T).

Arenibacter gen. nov., new genus of the family flavobacteriaceae and description of a new species, Arenibacter latericius sp. nov

Five dark-orange-pigmented, Gram-negative, rod-shaped, non-motile, aerobic bacterial strains were isolated from sandy sediment samples collected in the South China Sea in the Indian Ocean, from a holothurian, Apostichopus japonicus, in the Sea of Japan and from a brown alga, Chorda filum, from the Sea of Okhotsk in the Pacific Ocean. Phenotypic data were collected, demonstrating that the bacteria are chemo-organotrophic and require seawater-based media for growth. Polar lipids were analysed and 27% of the total extract comprised phosphatidylethanolamine as the major component. The predominant cellular fatty acids were branched-chain saturated and unsaturated [i-C15:0, i-C15:1, a-C15:0, C15:0, C16:1(n-7)]. The DNA base composition was 37.5-38.2 mol % G+C. The level of DNA homology of the five isolates was 83-94%, indicating that these isolates belong to the same species. A 16S rDNA sequence of the type strain KMM 426T was determined and phylogenetic analysis, based on neighbour-joining and Fitch-Margoliash methods, revealed that the type strain formed a distinct phyletic line in a clade corresponding to the family Flavobacteriaceae and represented a new genus. From the results of this polyphasic taxonomic analysis, it is proposed that the bacterial strains be classified in a new genus, Arenibacter gen. nov., and species, Arenibacter latericius sp. nov. The type strain is KMM 426T (VKM B 2137DT = LMG 19694T = CIP 106861T).

[Diversity in the monosaccharide composition of antigenic polysaccharides from proteobacteria Pseudoalteromonas and Marinomonas genera]

The sugar analysis of the glycans of the type strains of marine proteobacteria of the genera Pseudoalteromonas and Marinomonas--Pseudoalteromonas atlantica IAM12927T, P. aurantia NCIMB 2033T, P. citrea ATCC 29719T, P. elyakovii KMM 162T, P. espejiana ATCC 29659T, P. piscicida NCIMB 645T, P. tetraodonis IAM 14160T, Marinomonas communis ATCC 27118T, and M. vaga ATCC 27119T--showed that they contain glucose, galactose, galactosamine, glucosamine, fucose, rhamnose, mannose, heptose, 2-keto-3-deoxyoctonate (KDO), uronic acids, colitose (3,6-dideoxyl-L-xylo-hexose), and 6-deoxy-L-talose. The carbohydrate composition of the antigenic polysaccharides (PSs) of P. elyakovii KMM 162T and P. espejiana ATCC 29659T depended on the type and the concentration of carbohydrate substrates in the nutrient media. The molar proportion between rhamnose, glucose, and galactose (ca. 1:0.3:2) in the PS of P. elyakovii KMM 162T was almost the same in the media lacking carbohydrates or containing glucose or galactose at a concentration of 1 g/l. At the same time, the molar proportion between fucose, glucose, galactose, galactosamine, and glucosamine (ca. 1:1:1:2:0.5) in the PS of P. espejiana ATCC 29659T depended on the presence and the concentration of carbohydrate substrates in the medium. A high concentration of glucose in the medium (30 g/l) brought about a rise in the content of glucose in PSs (9-fold for the PS of P. elyakovii KMM 162T and 4.6-fold for the PS of P. espejiana ATCC 29659T) and led to a decrease in the content of other carbohydrates. The cultivation of these two strains at a lactose concentration of 30 g/l resulted in their PSs containing glucose and galactose in about equal proportions (ca. 1:1 in the case of P. espejiana ATCC 29659T and ca. 2.1:1.7 in the case of P. elyakovii KMM 162T).

Chemical characterization of lipid A from some marine proteobacteria

Lipids A from type and wild strains of marine Proteobacteria belonging to Alteromonadaceae (Alteromonas (1 species), Idiomarina (1 species), and Pseudoalteromonas (8 species) genera) and Vibrionaceae (Shewanella (1 species) and Vibrio (1 species) genera) families and Marinomonas genus (1 species) were isolated by hydrolysis of their respective lipopolysaccharides with 1% acetic acid. Based on thin-layer chromatography data, the lipids A studied had low heterogeneity and generated family-specific patterns varying in numbers of bands and their chromatographic mobility. Total chemical analysis of the compounds showed that they contained glucosamine, phosphate, and fatty acids with decanoate (I. zobellii KMM 231(T) lipid A) or dodecanoate (lipids A of the other bacteria) and 3-hydroxy alkanoates as the major fatty acid components. Unlike terrestrial bacterial lipids A, lipids A of marine Proteobacteria had basically monophosphoryl (except V. fluvialis AQ 0002B lipid A with its two phosphate groups) and pentaacyl (except S. alga 48055 and V. fluvialis AQ 0002B lipids A which were found to have six residues of fatty acids per molecule of glucosamine disaccharide) structural types, low toxicity, and may be useful as potential endotoxin antagonists.

Structure of a colitose-containing O-specific polysaccharide of the marine bacterium Pseudoalteromonas tetraodonis IAM 14160(T)

O-specific polysaccharide was isolated by mild acid degradation of the lipopolysaccharide of Pseudoalteromonas tetraodonis type strain IAM 14160(T) and studied by sugar and methylation analyses along with 1H and 13C NMR spectroscopy, including 2D COSY, TOCSY, 1H,(13)C HMQC and HMBC experiments. The polysaccharide was found to consist of hexasaccharide repeating units containing one residue each of D-Gal, D-GlcA, D-GalNAc and D-GlcNAc and two residues of 3,6-dideoxy-L-xylo-hexose (colitose, Col) and having the following structure:In common with the polysaccharides of some other bacteria, the polysaccharide studied contains a tetrasaccharide fragment alpha-Colp-(1-->2)-beta-D-Galp-(1-->3)-[alpha-Colp-(1-->4)]-beta-D-GlcpNAc, which is a colitose ('3-deoxy-L-fucose') analogue of the Lewis(b) blood group antigenic determinant.

Characterization of Aeromonas and Vibrio species isolated from a drinking water reservoir

AIMS

To study the phenotypic and chemotaxonomic (i.e. phospholipid and cellular fatty acid composition) characteristics of environmental Aeromonas spp. and Vibrio spp. isolated from a drinking water reservoir near Vladivostok City, and the application of some chemotaxonomic markers for discrimination of the two genera and species.

METHODS AND RESULTS

Presumptive Aeromonas species were dominant in surface water samples (up to 25% of the total number of bacteria recovered). These strains were consistent with respect to the cultural and biochemical properties used to define the species Aeromonas sobria (seven strains) and Aer. popoffii (three strains). Vibrio mimicus (two strains) and Vibrio metschnikovii (one strain) were identified according to phenotypic features and cellular fatty acid composition.

CONCLUSION

Environmental Aer. sobria isolates were atypical in their ability to grow at 42 degrees C, and were haemolytic, proteolytic and cytotoxic. Although it was present in a high proportion in the water samples, atypical Aer. sobria is not an indicator of polluted water.

SIGNIFICANCE AND IMPACT OF THE STUDY

The incidence of Aeromonas in the drinking water reservoirs in the Far East of Russia is reported for the first time.

Retrieval of the species Alteromonas tetraodonis Simidu et al. 1990 as Pseudoalteromonas tetraodonis comb. nov. and emendation of description

A polyphasic taxonomy study was undertaken of three strains of Pseudoalteromonas haloplanktis subsp. tetraodonis (Simidu et al. 1990) Gauthier et al. 1995. DNA was prepared from each of the strains and genomic relatedness was measured by DNA-DNA hybridization. Strains KMM 458T and IAM 14160T shared 99% genetic relatedness, but were only 48-49% related to the type strain of Pseudoalteromonas haloplanktis subsp. haloplanktis, IAM 12915T. The third strain, P. haloplanktis subsp. tetraodonis A-M, showed 83% genetic similarity with P. haloplanktis subsp. haloplanktis IAM 12915T and 32% with KMM 458T. From these results, it is concluded that strains KMM 458T and IAM 14160T comprise a separate species, originally described as Alteromonas tetraodonis, whereas strain A-M belongs to the species Pseudoalteromonas haloplanktis. Based on phenotypic and chemotaxonomic data, genomic fingerprint patterns, DNA-DNA hybridization data and phylogenetic analysis of 16S rRNA, it is proposed that the species Alteromonas tetraodonis be retrieved and recognized as Pseudoalteromonas tetraodonis comb. nov. (type strain IAM 14160T = KMM 458T).

Shewanella japonica sp. nov

Two strains of agar-digesting bacteria, KMM 3299T and KMM 3300, respectively isolated from sea water and the mussel Protothaca jedoensis, have been characterized. Based on sequencing of the 16S rRNA gene, KMM 3299T showed the highest similarity (93-95%) to members of the genus Shewanella. The G+C contents of the DNAs of these strains were 43-44 mol%. The level of DNA homology between the two strains was conspecific (95%), indicating that they represent a distinct genospecies. These organisms were non-pigmented, Gram-negative, polarly flagellated, facultatively anaerobic, mesophilic, neutrophilic and able to degrade a wide range of high molecular mass polymers, including alginate, carrageenan, laminaran and agar. The novel organisms were susceptible to gentamycin, carbenicillin, lincomycin and oleandomycin. The predominant cellular fatty acids were i-15:0, 16:0, 16:1(n-7), 18:1(n-7). Eicosapentaenoic acid, 20:5(n-3), was detected in the two isolates at levels of 1-8%, depending on the temperature of cultivation. Phylogenetic evidence, together with phenotypic characteristics, showed that the two isolates studied constitute a novel species of the genus Shewanella. The name Shewanella japonica is proposed; the type strain is KMM 3299T(= LMG 19691T = CIP 106860T).

[A new family of Alteromonadaceae fam. nov., including the marine proteobacteria species Alteromonas, Pseudoalteromonas, Idiomarina i Colwellia]

The taxonomic position of the marine genera Alteromonas, Pseudoalteromonas, Idiomarina, and Colwellia within the gamma subclass of the class Proteobacteria were specified on the basis of their phenotypic, genotypic, and phylogenetic characteristics. Gram-negative aerobic bacteria of the genera Alteromonas, Pseudoalteromonas, and Idiomarina and facultatively anaerobic bacteria of the genus Colwellia were found to form a phylogenetic cluster with a 16S rRNA sequence homology of 90% or higher. The characteristics of these genera presented in this paper allow their reliable taxonomic identification. Based on the analysis of our experimental data and analyses available in the literature, we propose to combine the genera Alteromonas, Pseudoalteromonas, Idiomarina, and Colwellia into a new family, Alteromonadaceae fam. nov., with the type genus Alteromonas.

Evaluation of phospholipid and fatty acid compositions as chemotaxonomic markers of Alteromonas-like proteobacteria

The cellular phospholipids (PLs) and fatty acids (FAs) were investigated in type and environmental strains of Pseudoalteromonas, Alteromonas macleodii, A. infernus, and in three type strains of Marinomonas, M. communis, M. vaga, M. mediterranea. A total of 40 strains (19 strains in this study and 21 reported in previous papers), including Idiomarina abyssalis, I. zobellii, and Glaciecola punicea, G. pallidula, aerobic Alteromonas-like proteobacteria showed genus-characteristic patterns of phospholipids and fatty acids useful for genera discrimination. The PL patterns of surface cultures of alteromonads, pseudoalteromonads, and marinomonads consisted almost entirely of phosphatidyl ethanolamine and phosphatidyl glycerol presented in different proportions. Neither diphosphatidyl glycerol nor glycophospholipids were found in bacteria studied. In addition, the minor amount of a glycolipid was found in all strains studied. Bacteria of the genera Marinomonas, Idiomarina, and Glaciecola were clearly distinguished by presence of one of the major FAs: 18:1 (n-7), i15:0, and 16:1 (n-7), respectively. The amounts of these FAs reached up to 40-60% of total FAs. Members of Alteromonas and Pseudoalteromonas were characterized by different ratio of the following major FAs:16:1(n-7), 16:0, 17:1 (n-8), and 18:1 (n-7).

[Microbiological monitoring of causative agents of sapronoses in the water of the Bogatinskoe water reservoir]

The results of the microbiological monitoring of potential causative agents of sapronoses in the water of the Bogatinskoye reservoir revealed that in the summer period of 1998 the mass accumulation of virulent Aeromonas sobria (up to 25% of the total number of heterotrophic bacteria) took place. The autumn period was characterized by a decrease in the number of A. sobria and the detection of bacteria of the genus Vibrio (up to 22%) with V. mimicus and V. metschnikovii identified among them in the water ecosystems of the southern regions of the Maritime Territory.

[Features of phospholipid composition of marine proteobacteria of Pseudoalteromonas species]

The study of the phospholipid composition of 14 type strains of marine proteobacteria of the genus Pseudoalteromonas showed that phospholipids are the main polar lipid constituents of membranes in these proteobacteria. The phospholipid patterns of the strains studied were found to be similar and involved five phospholipids typical of gram-negative bacteria, namely, phosphatidylethanolamine, phosphatidylglycerol, bisphosphatidic acid, lysophosphatidylethanolamine, and phosphatidic acid. The major phospholipids were phosphatidylethanolamine and phosphatidylglycerol, which add up to 89-97% of total phospholipids; bisphosphatidic acid was dominant among minor phospholipids. The prevalence of phosphatidylethanolamine (62-77% of total phospholipids) and the absence of diphosphatidylglycerol are the characteristic features of most bacteria of this genus. As in Escherichia coli, the phospholipid composition of the marine proteobacteria depended on the presence of magnesium in the medium.

Idiomarina gen. nov., comprising novel indigenous deep-sea bacteria from the Pacific Ocean, including descriptions of two species, Idiomarina abyssalis sp. nov. and Idiomarina zobellii sp. nov

Two bacterial strains, KMM 227T and 231T, were isolated from seawater samples collected from the north-western Pacific Ocean at a depth of 4000-5000 m and were characterized using polyphasic taxonomy. Both were Gram-negative, psychrotolerant, heterotrophic, aerobic and required NaCl for growth (0.6-15.0%). The temperature for growth was 4-30 degrees C. Both strains were rod-shaped, with a single flagellum. However, strain KMM 231T revealed a single long fimbrium. Cellular fatty acids detected in the isolates were predominantly odd-numbered and iso-branched, with 15 and 17 carbons (ca. 70%). Also present were saturated and monounsaturated straight-chain fatty acids. Results of phylogenetic analyses, employing three tree-making methods, strongly indicated that the two strains formed a distinct lineage within a clade containing the genera Alteromonas, Colwellia and Pseudoalteromonas, in the gamma-Proteobacteria. The two strains shared 16S rDNA sequence similarity of 96.9% and genomic DNA relatedness of 27%; the latter was determined by dot-blot hybridization. The strains were differentiated by the presence of fimbria, production of chitinase, ability to grow on 15% NaCl and BIOLOG profiles. Given the polyphasic evidence accumulated in this study, it is proposed that the two deep-sea isolates be classified in the genus Idiomarina gen. nov., as Idiomarina abyssalis sp. nov. (type strain is KMM 227T) and Idiomarina zobellii sp. nov. (type strain is KMM 231T).

Assignment of Alteromonas elyakovii KMM 162T and five strains isolated from spot-wounded fronds of Laminaria japonica to Pseudoalteromonas elyakovii comb. nov. and the extended description of the species

A marine bacterium, Alteromonas elyakovii KMM 162T, which was described recently, and five strains isolated from spot-wounded fronds of Laminaria japonica have been subjected to phylogenetic analysis, and geno- and phenotypic characterization. The phenotypic features of Pseudoalteromonas elyakovii strains were closely related to that of Pseudoalteromonas espejiana IAM 12640T, but utilization of three carbon compounds (D-mannose, L-tyrosine and trehalose) distinguished both species. The G+C content of Pseudoalteromonas elyakovii was between 38.5 and 38.9 mol%. Pseudoalteromonas elyakovii KMM 162T and the five Laminaria isolates constitute a single species different from any other Alteromonas and Pseudoalteromonas species as revealed by DNA-DNA hybridization data, especially Pseudoalteromonas distincta KMM 638T (52.4%), Pseudoalteromonas citrea KMM 216 (49.5%), Pseudoalteromonas carrageenovora NCIMB 302T (46.9%) and Pseudoalteromonas espejiana IAM 12640T (29.9%). All the data indicated that Alteromonas elyakovii KMM 162T should be reclassified as Pseudoalteromonas elyakovii and five strains isolated from Laminaria japonica have to be included in the species. Pseudoalteromonas elyakovii comb. nov. (type strain, KMM 162T = ATCC 700519T) is proposed and a set of phenotypic features which differentiate the Pseudoalteromonas species is described.

Reclassification of Alteromonas distincta Romanenko et al. 1995 as Pseudoalteromonas distincta comb. nov

The 16S rRNA gene of Alteromonas distincta KMM 638T was amplified, cloned and sequenced. The nucleotide sequence was aligned with sequences of representative strains of Alteromonas, Moritella, Pseudoalteromonas and Shewanella. Results of phylogenetic analysis, using neighbour-joining and Fitch-Margoliash methods, clearly indicated that this species should be assigned to the genus Pseudoalteromonas. On the basis of polyphasic data obtained from previous work and this study, it is proposed that the species Alteromonas distincta be reclassified as Pseudoalteromonas distincta comb. nov. with type strain KMM 638T (= ATCC 700518T).

Characterization of Bacillus strains of marine origin

A total of twenty aerobic endospore-forming bacilli, isolated from marine invertebrates and sea water of different areas of the Pacific Ocean, were taxonomically characterized. Most of the bacilli (11 strains) of marine origin belonged to the species Bacillus subtilis, according to their phenotypic characteristics, antibiotic susceptibility profiles, and fatty acids patterns. A group of four alkaliphilic strains formed a separate cluster that was tentatively classified as B. horti. One isolate, KMM 1717, associated with a sponge from the Coral Sea was identified as B. pumilus. Two strains, Bacillus KMM 1916 and KMM 1918, showed antibiotic sensitivity profiles similar to B. licheniformis, but they had a distinct fatty acid composition and peculiar phenotypic traits. The taxonomic affiliation of KMM 1810 and KMM 1763 remained unclear since their fatty acid composition and antibiotic sensitivity patterns were not resembled with none of these obtained for Bacillus strains.

[Structure of glycerophosphate-containing O-specific polysaccharide from Pseudoalteromonas sp. KMM 639]

On the basis of acid hydrolysis, dephosphorylation, methylation, and 13C NMR spectroscopy data, the O-specific polysaccharide of Pseudoalteromonas sp. KMM 639 was shown to be a glycerophosphate-containing polymer built of repeating disaccharide units of the following structure: [formula: see text]

Structure of the O-specific polysaccharide from Pseudoalteromonas elyakovii sp. nov. CMM 162

The structure of the O-specific polysaccharide from lipopolysaccharide of Pseudoalteromonas elyakovii sp. nov. CMM 162 on the basis of NMR data, Smith degradation and methylation study was elucidated as follows:-->2)-alpha-D-Glcp-(1-->4)-beta-D-GalpNAc-(1--> 3)-alpha-D-Galp-(1-->3)-beta-D-Galp-NAc-(1-->6)-alpha-D-Glcp-(1-->.

Phenotypic diversity of Pseudoalteromonas citrea from different marine habitats and emendation of the description

Four strains of marine, aerobic, agar-decomposing bacteria with one polar flagellum and with DNA G + C contents of 38.9-40.2 mol% were isolated from the Far-Eastern mussels Crenomytilus grayanus and Patinopecten yessoensis. These four strains were identified as Pseudoalteromonas; however, they were phenotypically different from species described previously according to carbon compound utilization tests and the BIOLOG identification system. High agar-decomposing activity was found in two strains, in one of which agarase, alpha-galactosidase, pustulanase and laminarinase had been detected. The level of DNA homology of three of the strains was 70-100%. The fourth isolate was genetically less related to the others (67% DNA relatedness) and phenotypically was more distant from other members of this group; however, all four strains were assigned to a single species genotypically. DNA from the strains isolated from mussels showed 40-45% genetic relatedness with the DNA of Alteromonas atlantica, 8-36% with DNA of Pseudoalteromonas haloplanktis subsp. haloplanktis, Pseudoalteromonas haloplanktis subsp. tetraodonis, Pseudoalteromonas undina, Pseudoalteromonas nigrifaciens and Pseudoalteromonasas carrageenovora, 53% with Pseudoalteromonas elyakovii, 32-48% with marine P. nigrifaciens from mussels and 14-16% with Alteromonas macleodii. The DNA-DNA hybridization data revealed that the levels of relatedness between the strains isolated and the type strains of Pseudoalteromonas citrea and Pseudoalteromonas fuliginea described recently were significant (95-85%). These results were confirmed by serological data employing polyclonal antibodies to cell surface antigens. The strains isolated from mussels were identified as P. citrea. The hybridization data showed that the name P. fuliginea Romanenko et al. 1994 should be recognized as a junior subjective synonym of P. citrea Gauthier 1977. A notable phenotypic diversity of P. citrea which might be a reflection of their ecological habitats is discussed.