Macrochaete gen. nov. (Nostocales,Cyanobacteria), a taxon morphologically and molecularly distinct from Calothrix

Historically, the genus Calothrix included all noncolonial, tapered, heterocytous filaments within the cyanobacteria. However, recent molecular phylogenies show that “Calothrix” defined in this sense represents five distinct clades. The type species of Calothrix is marine, with solitary basal heterocytes, no akinetes, and distal ends tapering abruptly into short hairs. We examined the morphology and phylogeny of 45 tapering cyanobacteria in the Rivulariaceae, including freshwater and marine representatives of both Calothrix (35 strains) and its sister taxon Rivularia (10 strains). The marine Calothrix fall into two lineages, but we lack the generitype and so cannot identify the clade corresponding to the type species. The freshwater and soil Calothrix fall into the C. parietina clade and are characterized by having a basal heterocyte, no akinetes, and gradual tapering—but not into a long hyaline hair. Macrochaete gen. nov. is a freshwater taxon sister to the Calothrix lineages but clearly separated from Rivularia. The species in this genus differ morphologically from Calothrix by their ability to produce two heteromorphic basal heterocytes and specific secondary structures of the 16S–23S ITS. An additional feature present in most species is the presence of a distal, long hyaline hair, but this character has incomplete penetrance due to its expression only under specific environmental conditions (low phosphate), and in one species appears to be lost. We recognize three species: M. psychrophila (type species) from cold environments (high mountains, Antarctica), M. santannae from wet walls of subtropical South America, and M. lichenoides, a phycobiont of lichens from Europe.     

Halorussus rarus gen. nov., sp. nov., a new member of the family Halobacteriaceae isolated from a marine solar saltern

Two halophilic archaeal strains TBN4^T and TBN5 were isolated from Taibei marine solar saltern in Jiangsu, China. Both strains showed light red-pigmented colonies and their cells were rod, motile and Gram-stain-negative. They were able to grow at 25–50°C (optimum 37°C), at 1.4–4.3 M NaCl (optimum 2.1 M NaCl), at 0–1.0 M MgCl₂ (optimum 0.005 M MgCl₂) and at pH 6.0–9.0 (optimum pH 7.0). Their cells lyse in distilled water and minimal NaCl concentration to prevent cell lysis is 8% (w/v). The major polar lipids of the two strains were PG (phosphatidylglycerol), PGP-Me (phosphatidylglycerol phosphate methyl ester), PGS (phosphatidylglycerol sulfate) and five glycolipids chromatographically identical to S-TGD-1 (sulfated galactosyl mannosyl glucosyl diether), S-DGD-1 (sulfated mannosyl glucosyl diether), TGD-1 (galactosyl mannosyl glucosyl diether), DGD-1 (mannosyl glucosyl diether) and DGD-2 (an unknown diglycosyl diether). Phylogenetic analysis revealed that TBN4^T and strain TBN5 formed a distinct clade with genus Haladaptatus (showing 90.0–90.9% 16S rRNA gene similarities). The DNA G + C content of strain TBN4^T and strain TBN5 are 66.1 and 65.4 mol%, respectively. The DNA–DNA hybridization value between strain TBN4^T and strain TBN5 was 94.3%. The phenotypic, chemotaxonomic and phylogenetic properties suggest that strain TBN4^T and strain TBN5 represent a novel species in a new genus within the family Halobacteriaceae, for which the name Halorussus rarus gen. nov., sp. nov. is proposed. The type strain is TBN4^T (=CGMCC 1.10122^T = JCM 16429^T).     

Natronobacillus azotifigens gen. nov., sp. nov., an anaerobic diazotrophic haloalkaliphile from soda-rich habitats

Gram-positive bacteria capable of nitrogen fixation were obtained in microoxic enrichments from soda soils in south-western Siberia, north-eastern Mongolia, and the Lybian desert (Egypt). The same organisms were obtained in anoxic enrichments with glucose from soda lake sediments in the Kulunda Steppe (Altai, Russia) using nitrogen-free alkaline medium of pH 10. The isolates were represented by thin motile rods forming terminal round endospores. They are strictly fermentative saccharolytic anaerobes but tolerate high oxygen concentrations, probably due to a high catalase activity. All of the strains are obligately alkaliphilic and highly salt-tolerant natronophiles (chloride-independent sodaphiles). Growth was possible within a pH range from 7.5 to 10.6, with an optimum at 9.5–10, and within a salt range from 0.2 to 4 M Na⁺, with an optimum at 0.5–1.5 M for the different strains. The nitrogenase activity in the whole cells also had an alkaline pH optimum but was much more sensitive to high salt concentrations compared to the growing cells. The isolates formed a compact genetic group with a high level of DNA similarity. Phylogenetic analysis based on 16S-rRNA gene sequences placed the isolates into Bacillus rRNA group 1 as a separate lineage with Amphibacillus tropicus as the nearest relative. In all isolates the key functional nitrogenase gene nifH was detected. A new genus and species, Natronobacillus azotifigens gen. nov., sp. nov., is proposed to accommodate the novel diazotrophic haloalkaliphiles. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users. The GenBank accession numbers for the 16S rRNA gene of the novel strains are EU143681-EU143690 and EU850814-EU850816; for the nifH gene the accession numbers are EU542601, EU563380-EU563386 and EU850817-EU850819.     

Amycolatopsis bartoniae sp. nov. and Amycolatopsis bullii sp. nov., mesophilic actinomycetes isolated from arid Australian soils

The status of two mesophilic filamentous actinomycetes isolated from an arid Australian soil sample was determined using a polyphasic taxonomic approach. The isolates had chemical and morphological properties consistent with their classification in the genus Amycolatopsis, assignments that were supported by analysis of 16S rRNA gene sequence data. Isolate SF26^T formed a distinct phyletic line and hence was sharply separated from its nearest phylogenetic neighbour, Amycolatopsis sacchari DSM 44468^T. In contrast, isolate SF27^T formed a subclade in the Amycolatopsis tree with Amycolatopsis vancoresmycina DSM 44592^T but was separated readily from the latter by DNA:DNA pairing data. The two isolates were distinguished from one another and from their respective nearest phylogenetic neighbours using a range of phenotypic properties. These data indicate that the two isolates should be recognized as new species in the genus Amycolatopsis. The names proposed for these new taxa are Amycolatopsis bartoniae sp. nov. and Amycolatopsis bullii sp. nov. with isolates SF26^T (=NCIMB 14706^T = NRRL B-2846^T) and SF27^T (=NCIMB 14707^T = NRRL B-24847^T) as the respective type strains.     

Microcella flavibacter sp. nov., isolated from marine sediment,and reclassification of Chryseoglobus frigidaquae,Chryseoglobus indicus,and Yonghaparkia alkaliphila as Microcella frigidaquae comb. nov., Microcella indica nom. nov., and Microcella alkalica nom. nov.

A novel Gram-staining positive, aerobic, rod-shaped, non-motile and yellow-pigmented actinobacterium, designated strain WY83^T, was isolated from a marine sediment of Indian Ocean. Strain WY83^T grew optimally at 30–35 °C, pH 7–8 and with 0–3% (w/v) NaCl. The predominant menaquinones were MK-10, MK-11 and MK-12, and the major fatty acids were C_19:1 ω9c/C19:1 ω11c, anteiso-C_15:0, C_17:0 3OH, and iso-C_16:0. The polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol and one unidentified glycolipid. The cell-wall peptidoglycan contained lysine as a diamino acid. The DNA G?+?C content was 72.3 mol%. Phylogenetic analysis based on 16S rRNA gene sequences and ninety-two bacterial core genes indicated that strain WY83^T formed an evolutionary lineage with Chryseoglobus frigidaquae JCM 14730^T, Chryseoglobus indicus CTD02-10-2^T, Yonghaparkia alkaliphila JCM 15138^T, Microcella alkaliphila DSM 18851^T and Microcella putealis DSM 19627^T within the radiation enclosing members of the family Microbacteriaceae. All pairwise percentage of conserved proteins between strain WY83^T and the closely related phylogenetic neighbors were greater than 65%. The average nucleotide identity and in silico DNA–DNA hybridization values were both below the thresholds used for the delineation of a new species. On the basis of the evidence presented, strains WY83^T, Y. alkaliphila JCM 15138^T, C. frigidaquae JCM 14730^T, M. alkaliphila DSM 18851^T and M. putealis DSM 19627^T should belong to different species of the same genus. Strain WY83^T represents a novel species of the genus Microcella, for which the name Microcella flavibacter sp. nov. is proposed. The type strain is WY83^T (=?KCTC 39637^T?=?MCCC 1A07099^T). Furthermore, Chryseoglobus frigidaquae, Chryseoglobus indicus, and Yonghaparkia alkaliphila were reclassified as Microcella frigidaquae comb. nov., Microcella indica nom. nov., and Microcella alkalica nom. nov., respectively.

     

Cohnella boryungensis sp. nov., isolated from soil

A Gram-staining positive, endospore-forming, motile and rod-shaped bacterial strain, BR-29^T, was isolated from soil from west coast of the Korean peninsula, and its taxonomic position was investigated by a polyphasic study. Strain BR-29^T grew optimally at around pH 7.5, at 30°C and in the presence of 0.5% (w/v) NaCl. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain BR-29^T fell into a clade comprising the type strains of Cohnella species, with which it exhibited 16S rRNA gene sequence similarity values of 92.8–96.4%. Strain BR-29^T contained a cell wall peptidoglycan based on meso-diaminopimelic acid and MK-7 as the predominant menaquinone. The major fatty acids were anteiso-C_15:0, C_16:0 and iso-C_16:0. The major polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, lysylphosphatidylglycerol and two unidentified phospholipids; a minor amount of phosphatidylglycerol was present. The DNA G+C content was 54.9 mol%. Strain BR-29^T could be differentiated from phylogenetically related Cohnella species by differences in phenotypic characteristics. On the basis of phenotypic, chemotaxonomic and phylogenetic data, strain BR-29^T represents a novel species of the genus Cohnella, for which the name Cohnella boryungensis sp. nov., is proposed. The type strain is BR-29^T (= KCTC 13735^T = CCUG 59598^T).     

Rufibacter tibetensis gen. nov., sp. nov., a novel member of the family Cytophagaceae isolated from soil

A red-pigmented, Gram-negative, strictly aerobic, rod-shaped bacterium which was motile by gliding, designated strain 1351^T, was isolated from the soil of Lengduo, Tibet in China and subjected to a polyphasic taxonomic analysis. The isolate grows optimally at 30°C and pH 7. It grows with NaCl tolerated up to 1.5% (optimum, 0.5%). Phylogenetic analysis based on the 16S rRNA gene sequence shows that strain 1351^T is closely related to members of the family ‘Cytophagaceae’ closest sequence similarity was observed with similarity with Adhaeribacter terreus (91.8%). The major whole-cell fatty acids are summed feature 4 (containing anteiso-C_17:1 B and/or iso-C_17:1 I, 29.2%), summed feature 3 (containing C_16:1ω6c and/or C_16:1ω7c, 13.0%) and iso-C_15:0 (12.0%). The predominant menaquinone of strain 1351^T is menaquinone-7 (MK-7) and the G+C content of the DNA is 46.8 mol%. According to the phylogenetic evidence and phenotypic data, strain 1351^T is considered to represent a new genus and species of the family ‘Cytophagaceae’ for which the name Rufibacter tibetensis gen nov., sp. nov. is proposed. The type species is R. tibetensis and the type strain is 1351^T (=CCTCC AB 208084^T = NRRL B-51285^T).     

Description of Fimbriimonas ginsengisoli gen. nov., sp. nov. within the Fimbriimonadia class nov., of the phylum Armatimonadetes

Strain Gsoil 348^T was isolated from a ginseng field soil sample by selecting micro-colonies from one-fifth strength modified R2A agar medium after a long incubation period. 16S rRNA gene sequence analysis indicated that the strain is related to members of the phylum Armatimonadetes (formerly called candidate phylum OP10). Strain Gsoil 348^T is mesophilic, strictly aerobic, non-motile and rod-shaped. It only grows in low nutrient media. The major respiratory quinones are menaquinones MK-11 and MK-10, and the main fatty acids are iso-C_15:0, iso-C_17:0, C_16:0 and C_16:1 ω11c. The G+C content is 61.4 mol%. The 16S rRNA gene sequences in public databases belonging to the phylum Armatimonadetes were clustered here into 6 groups. Five of these groups constituted a coherent cluster distinct from the sequences of other phyla in phylogenetic trees that were constructed using multiple-outgroup sequences from 49 different phyla. On the basis of polyphasic taxonomic analyses, it is proposed that strain Gsoil 348^T (= KACC 14959^T = JCM 17079^T) should be placed in Fimbriimonas ginsengisoli gen. nov., sp. nov., as the cultured representative of the Fimbriimonadia class. nov., corresponding with Group 4 of the phylum Armatimonadetes.     

Methylosulfonomonas methylovora gen. nov., sp. nov., and Marinosulfonomonas methylotropha gen. nov., sp. nov.: novel methylotrophs able to grow on methanesulfonic acid

Two novel genera of restricted facultative methylotrophs are described; both Methylosulfonomonas and Marinosulfonomonas are unique in being able to grow on methanesulfonic acid as their sole source of carbon and energy. Five identical strains of Methylosulfonomonas were isolated from diverse soil samples in England and were shown to differ in their morphology, physiology, DNA base composition, molecular genetics, and 16S rDNA sequences from the two marine strains of Marinosulfonomonas, which were isolated from British coastal waters. The marine strains were almost indistinguishable from each other and are considered to be strains of one species. Type species of each genus have been identified and named Methylosulfonomonas methylovora (strain M2) and Marinosulfonomonas methylotropha (strain PSCH4). Phylogenetic analysis using 16S rDNA sequencing places both genera in the α-Proteobacteria. Methylosulfonomonas is a discrete lineage within the α-2 subgroup and is not related closely to any other known bacterial genus. The Marinosulfonomonas strains form a monophyletic cluster in the α-3 subgroup of the Proteobacteria with Roseobacter spp. and some other partially characterized marine bacteria, but they are distinct from these at the genus level. This work shows that the isolation of bacteria with a unique biochemical character, the ability to grow on methanesulfonic acid as energy and carbon substrate, has resulted in the identification of two novel genera of methylotrophs that are unrelated to any other extant methylotroph genera. Received: 19 July 1996 / Accepted: 7 October 1996     

Fuscibacter oryzae gen. nov., sp. nov., a phosphate-solubilizing bacterium isolated from the rhizosphere of rice plant

An ovoid to rod shaped, white to brown pigmented, facultative anaerobic, mesophilic, non-phototrophic, Gram-staining-negative, non-motile, multiply by binary fission designated strain KVB23^T, which was isolated from root of rice plant, near Ilsan, South Korea, was investigated for its taxonomic position by polyphasic approach. Optimal growth was found to occur at 30?C, at pH 6.5 and in the absence of NaCl on R2A. Phylogenetic analysis based on the 16S rRNA gene sequence of strain KVB23^T revealed that it formed a distinct lineage, as a separate deep branch within the family Rhodobacteriaceae, with?<?96.5% sequence similarity to representatives of the genera Rhodobacter, Xinfangfangia, Tabrizicola, Falsirhodobacter, Haematobacter, Paenirhodobacter, Pseudorhodobacter and Pararhodobacter. Based in 16S rRNA sequences strain KVB23^T was most closely related to Tabrizicola fusiformis KCTC 62105 ^T (96.5%) and Rhodobacter thermarum KCTC 52712 ^T (96.2%). The draft genome of strain KVB23^T was 3.80 bp long with a DNA G?+?C content of 63.1%. Genome of strain KVB23^T harboured gene clusters for tryptophan and cobalamin biosynthesis. The strain contained Q-10 as the sole respiratory quinone. The predominant fatty acids were found to consist of C_16:0, C_18:0 and summed feature 8 (comprising C_18:1 ω7c and / or C_18:1 ω6). The polar lipids were identified as diphosphatidylglycerol, phosphatidylethanolamine, seven unidentified phosphoglycolipids, two unidentified aminophosphoglycolipid, one unidentified glycolipid and four unidentified lipids. Phosphate-solubilizing bacteria have the ability to dissolve insoluble phosphates and enhance the soil fertility. Strain KVB23^T can solubilize calcium phosphate tribasic. Phosphate solubilizing and tryptophan biosynthesis property of strain KVB23^T could be a possible factor for the increase in growth of rice plant. Differential phenotypic, chemotaxonomic and genotypic properties, together with the phylogenetic distinctiveness, demonstrated that strain KVB23^T was found to represent a novel genus in the Rhodobacteriaceae family, for which the name Fuscibacter oryzae gen. nov., sp. nov. is proposed, with the type strain KVB23^T(=?KACC 21711 ^T?=?NBRC 114716 ^T).

     

Streptomyces deserti sp. nov., isolated from hyper-arid Atacama Desert soil

The taxonomic position of a Streptomyces strain isolated from a hyper-arid desert soil was established using a polyphasic approach. The organism had chemical and morphological properties typical of the genus Streptomyces and formed a phyletic line at the periphery of the Streptomyces coeruleorubidus subcluster in the 16S rRNA gene tree. DNA:DNA relatedness values between the isolate and its nearest phylogenetic neighbours, Streptomyces lomondensis NRRL 3252^T and Streptomyces lusitanus NRRL B-12501^T were 42.5 (±0.48)% and 25.0 (±1.78)%, respectively. The isolate was readily distinguished from these organisms using a combination of morphological and phenotypic properties. On the basis of these results, it is proposed that isolate C63^T (CGMCC 4.6997^T, = KACC 15425^T) be classified as the type strain of Streptomyces deserti sp. nov.     

Deinococcus aestuarii sp. nov. and Deinococcus aquaedulcis sp. nov., two novel resistant bacteria isolated from pearl river estuary

Two novel species of the genus Deinococcus, designated SYSU M49105^T and SYSU M42101^T, were isolated from freshwater samples of the Pearl River estuary in Guangdong, China. Phylogenetic analysis using 16S rRNA gene sequence indicated that strains SYSU M49105^T and SYSU M42101^T showed the highest sequence similarities to Deinococcus aetherius JCM 11751 ^T (93.6%) and Deinococcus multiflagellatus NBRC 112888 ^T (97.3%), respectively. Cells of both strains were Gram-staining positive, aerobic, coccus-shaped, oxidase-negative and non-motile. The cell wall contained meso-diaminopimelic acid as their diagnostic diamino acid. MK-8 was the predominant respiratory quinone for both strains. The polar lipid profile of SYSU M49105^T contained two unidentified phosphoglycolipids, nine unidentified glycolipids, and five unidentified polar lipids. SYSU M42101^T had one unidentified phosphoglycolipid, nine unidentified glycolipids, one unidentified aminophospholipid and four unidentified polar lipids. The major fatty acids of strains SYSU M49105^T and SYSU M42101^T were summed feature 3 (C_16:1 ω7c and/ or C_16:1 ω6c) and C_16:0. The G?+?C contents of the novel isolates based on genomic DNAs were 69.6% and 67.4%, respectively. On the basis of phenotypic, genotypic and phylogenetic data, strains SYSU M49105^T and SYSU M42101^T should be considered to represent two novel species in the genus Deinococcus, for which the names Deinococcus aestuarii sp. nov. and Deinococcus aquaedulcis sp. nov. were proposed with the type strains SYSU M49105^T (=?KCTC 43258 ^T?=?CGMCC 1.18609 ^T) and SYSU M42101^T (=?KCTC 43257 ^T?=?CGMCC 1.18614 ^T), respectively.

     

Geodermatophilus nigrescens sp. nov., isolated from a dry-hot valley

A novel actinomycete, designated as strain YIM 75980^T, was isolated from a soil sample collected from a dry-hot river valley in Dongchuan county, Yunnan province, south-west China and was subjected to polyphasic taxonomic characterization. The organism produced circular, smooth, red to black coloured colonies comprising coccoid-shaped cells. Colonies on agar medium lacked mycelia and cells adhered to the agar. Strain YIM 75980^T contained meso-diaminopimelic acid as the diagnostic diamino acid in the cell-wall peptidoglycan and contained galactose, arabinose and glucosamine as the main sugars in the whole-cell hydrolysates. The predominant menaquinone was MK-9 (H₄) and the major fatty acids were iso-C_15:0, iso-C_16:0 and C_16:0. The DNA G + C content of strain YIM 75980^T was 73.1 mol%. Phylogenetic analyses based on 16S rRNA gene sequences clearly showed that strain YIM 75980^T formed a distinct clade within the genus Geodermatophilus and was closely related to Geodermatophilus obscurus DSM 43160^T (level of similarity, 97.9%). Furthermore, the result of DNA–DNA hybridization between strain YIM 75980^T and G. obscurus 43160^T demonstrated that this isolate represented a different genomic species in the genus Geodermatophilus. Moreover, the physiological and biochemical data showed the differentiation of strain YIM 75980^T from its closest phylogenetic neighbour. Therefore, it is proposed that strain YIM 75980^T represents a novel species of the genus Geodermatophilus, for which the name Geodermatophilus nigrescens sp. nov. is proposed. The type strain is YIM 75980^T (=CCTCC AA 2011015^T =JCM 18056^T).     

Haloalkaliphilic spore-forming sulfidogens from soda lake sediments and description of Desulfitispora alkaliphila gen. nov., sp. nov.

An anaerobic enrichment with pyruvate as electron donor and thiosulfate at pH 10 and 0.6 M Na⁺ inoculated with pasteurized soda lake sediments resulted in a sulfidogenic coculture of two morphotypes of obligately anaerobic haloalkaliphilic endospore-forming clostridia, which were further isolated in pure culture. Strain AHT16 was a thin long rod able to ferment sugars and pyruvate and to respire H₂, formate and pyruvate using thiosulfate and fumarate as electron acceptors and growing optimally at pH 9.5. Thiosulfate was reduced incompletely to sulfide and sulfite. The strain was closely related (99% sequence similarity) to a peptolytic alkaliphilic clostridium Natronincola peptidovorans. Strain AHT17 was a short rod with a restricted respiratory metabolism, growing with pyruvate and lactate as electron donor and sulfite, thiosulfate and elemental sulfur as electron acceptors with a pH optimum 9.5. Thiosulfate was reduced completely via sulfite to sulfide. The ability of AHT17 to use sulfite explained the stability of the original coculture of the two clostridia—one member forming sulfite from thiosulfate and another consuming it. Strain AHT17 formed an independent deep phylogenetic lineage within the Clostridiales and is proposed as a new genus and species Desulfitisporum alkaliphilum gen. nov., sp. nov. (=DSM 22410^T = UNIQEM U794^T).     

Fibrivirga algicola gen. nov., sp. nov., an algicidal bacterium isolated from a freshwater river

An aerobic, gram-stain-negative, pink-colored, non-motile and rod-shaped algicidal bacterium, designated as JA-25^T was isolated from freshwater in Geumgang River, Republic of Korea. Strain JA-25^T grew at 15–30 °C and pH 6–9, and did not require NaCl. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain JA-25^T belongs to the family ‘Spirosomaceae’ and is most closely related to Fibrella aestuarina BUZ 2^T (93.6%). Strain JA-25^T showed?<?90% sequence similarity to other members of the family ‘Spirosomaceae’. The average nucleotide identity(ANI), in silico DNA-DNA hybridization and average amino acid identity(AAI) values based on the genomic sequences of JA-25^T and F. aestuarina BUZ 2^T were 74.4, 20.5, and 73.6%, respectively. Strain JA-25^T showed an algicidal effect on the marine flagellate alga Heterocapsa triquetra, but no effect on fresh water cyanobacterium (Nostoc). In genome analysis, RIPP-like peptides were detected and predicted to resemble the indolmycin biosynthetic gene cluster, which possibly influence its algicidal effect. Furthermore, a bacteriorhodopsin gene with photoheterotrophic characteristics was detected. The genomic DNA G?+?C content was 52.5 mol%. The major cellular fatty acids were summed feature 3 (C16:1 ω6c/C16:1 ω7c), C16:1 ω5c, C16:0 (>?10%). The major respiratory quinone was menaquinone 7 and major polar lipids were phosphatidylethanolamine, two unidentified aminolipids, two phospholipids, and five unidentified lipids. Considering the phylogenetic inference, phenotypic, and chemotaxonomic data, strain JA-25^T should be classified as a novel species in the novel genus Fibrivirga, with the proposed name Fibrivirga algicola sp. nov. The type strain is JA-25^T (=?KCCM 43334^T?=?NBRC 114259^T).

     

Alexandriicola marinus gen. nov., sp. nov., a new member of the family Rhodobacteraceae isolated from marine phycosphere

Two yellow-pigmented bacterial strains, LZ-14 ^T and ABI-LZ29, were isolated from the cultivable phycosphere microbiota of the highly toxic marine dinoflagellate Alexandrium catenella LZT09 and demonstrated obvious microalgae growth-promoting potentials toward the algal host. To elucidate the taxonomic status of the two bioactive bacterial strains, they were subjected to a polyphasic taxonomic characterization. Both strains were found to be Gram-negative, aerobic, rod-shaped and motile; to contain Q-10 as the predominant ubiquinone; summed feature 8, C_16:0, C_18:1 ω7c 11-methyl and summed feature 3 as the major fatty acids; and diphosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol and two unidentified phospholipids as the predominant polar lipids. Based on the phylogenetic analysis, phylogenomic inferences and phenotypic characteristics, the strains could be clearly distinguished from phylogenetically closely related species and formed a distinct monophyletic lineage in the family Rhodobacteraceae. The size of the draft genome of strain LZ-14 ^T is 4.615 Mb, with a DNA G?+?C content of 63.3 mol%. It contains ten predicted secondary metabolite biosynthetic gene clusters and core genes for bacterial exopolysaccharide biosynthesis. Therefore, strain LZ-14 ^T (= CCTCC AB 2017230 ^T?=?KCTC 62342 ^T) represents a novel species of a new genus, for which the name Alexandriicola marinus gen. nov., sp. nov., is proposed.

     

Oceanibacterium hippocampi gen. nov., sp. nov., isolated from cutaneous mucus of wild seahorses (Hippocampus guttulatus)

A Gram-negative, aerobic, motile and slightly curved rod-shaped bacterium (BFLP-8^T) was isolated from cutaneous mucus of wild long-snouted seahorses (Hippocampus guttulatus) captured in northwest Spain (Toralla, Galicia). Strain BFLP-8^T grew at 10–35 °C and pH 5–9 (optimally at 25 °C and pH 7.0) and with 1–6 % (w/v) NaCl (optimally with 2 % NaCl). The predominant respiratory quinone (90 %) was ubiquinone with ten isoprene units (Q-10) and the major fatty acids identified were C_18:1 ω7c (54.8 % of the total), C_19:0 cyclo ω8c (11.6 %), C_16:0 (9.5 %), C_18:1 2-OH (7.1 %) and C_16:1 ω11c (6.7 %). The G+C content of the DNA was 57.8 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain BFLP-8^T formed a distinct clade within the family Sneathiellaceae but is not specifically associated with any species in the family. On the basis of phenotypic, chemotaxonomic and phylogenetic data, strain BFLP-8^T represents a novel species within a new genus, for which the name Oceanibacterium hippocampi gen. nov., sp. nov. is proposed. The type strain is BFLP-8^T (=CECT 7691^T = DSM 23444^T).     

Ectothiorhodosinus mongolicum gen. nov., sp. nov., a New Purple Bacterium from a Soda Lake in Mongolia

A new nonmotile purple sulfur bacterium (strain M9) was isolated from the steppe soda lake Lake Dzun Uldziin Nur (pH 9.4; mineralization, 3.3%) situated in southeastern Mongolia. Individual cells appear as vibrios 0.3–0.5 × 0.7–1 m in size. The dividing cells often do not separate from each other, forming an almost closed ring. The internal photosynthetic membranes are represented by concentric lamellae lining the cell wall. Photosynthetic pigments are bacteriochlorophyll a and carotenoids of the spirilloxanthin series. The main carotenoid (>96%) is spirilloxanthin. Two typical light-harvesting complexes (LH1 and LH2) are present in the membranes in a 1 : 1 ratio. The bacterium is an anaerobe and facultative photoorganoheterotroph. Photolithoautotrophic growth on sulfide is scarce. Thiosulfate is utilized as an electron donor only in the presence of organic matter. Globules of elemental sulfur are formed as an intermediary product of sulfide and thiosulfate oxidation and are deposited outside the cells. The end product of oxidation is sulfate. In the presence of sulfide and carbonates, acetate, lactate, malate, pyruvate, propionate, succinate, and fumarate are used as additional sources of carbon in anoxygenic photosynthesis. Vitamins are not required. The bacterium is an alkaliphile, the pH optimum is at 8.3–9.1, the pH range is 7.6–10.1. The optimum NaCl concentration in the medium is 1 to 7%; the range is 0.5 to 0.9%. The optimum carbonate content in the medium is 2%; the range is 1 to 10%. The best growth occurs at 30–35°C. The DNA G+C content is 57.5 mol %. According to the results of analysis of the 16S rRNA gene sequences, the new isolate M9 belongs to the phylogenetic cluster containing representatives of the family Ectothiorhodospiraceae within the class Gammaproteobacteria. In this class, the new isolate forms a new branch, which occupies an intermediate position between the representatives of the genera Ectothiorhodospira and Thiorhodospira. Based on the phenotypic and genetic characteristics, the new purple sulfur bacterium was assigned to a new species of a new genus of the family Ectothiorhodospiraceae, Ectothiorhodosinus mongolicum gen. nov., sp. nov.     

Alkalilactibacillus ikkensis, gen. nov., sp. nov., a novel enzyme-producing bacterium from a cold and alkaline environment in Greenland

Three novel Gram-positive, endospore-forming bacteria were isolated from a cold and alkaline environment. Phylogenetic analysis showed that the strains were almost identical, and that they were related to Natronobacillus azotifigens 24KS-1^T (95.8% identity), Paraliobacillus quinghaiensis YIM-C158^T (95.1%), Paraliobacillus ryukyuensis O15-7^T (94.5%), and Halolactibacillus miurensis M23-1^T (93.9%). The isolates produced amylase, α-galactosidase, β-galactosidase, and β-glucuronidase, and showed optimal growth at pH 10, at 20°C, and at 2–8% (w/v) NaCl. Major fatty acids were C_14:0 (10.6–11.6%), anteiso-C_15:0 (25.7–32.7%), C_16:1 ω11c (12.2–16.0%), and C_16:0 (14.0–20.4%). The major polar lipids were diphosphatidylglycerol and phosphatidylglycerol, and meso-diaminopimelic acid was found in the cell-wall peptidoglycan. The G+C content was 38.4%. DNA–DNA hybridization between strain GCM68^T and H. miurensis M23-1^T was 32.4%, while hybridization to N. azotifigens 24KS-1^T, Amphibacillus tropicus Z-7792^T, and Paraliobacillus ryukyuensis O15-7^T was below 30%. The phylogenetic analysis and G+C content place strain GCM68^T in relation to species belonging to Bacillus rRNA group 1, but phylogenetic and physiologic data combined with chemotaxonomic analyses support our proposal for a new genus, Alkalilactibacillus, gen. nov., with the novel species Alkalilactibacillus ikkensis, sp. nov. (type strain is GCM68^T = DSM 19937 = LMG 24405).     

Classification of novel soil streptomycetes as Streptomyces aureus sp. nov., Streptomyces laceyi sp. nov. and Streptomyces sanglieri sp. nov

The taxonomic positions of soil isolates known as Streptomyces groups A, B and C were clarified. Comparative 16S rDNA sequence studies indicated that representatives of all three taxa formed distinct phyletic lines within the Streptomyces tree though the group A strains were shown to be related to Streptomyces griseus and associated validly described species. The taxonomic integrity of all three groups was highlighted by DNA:DNA relatedness and ribotype data though the group A strains encompassed a higher degree of genetic variation than the group B and C strains. In light of these and earlier phenotypic data it is proposed that Streptomyces groups A, B and C be given species status as Streptomyces sanglieri sp. nov., Streptomyces aureus sp. nov. and Streptomyces laceyi sp. nov., respectively. This revised version was published online in June 2006 with corrections to the Cover Date.