Citreitalea marina gen. nov., sp. nov., a novel member of the family Flavobacteriaceae isolated from a marine red alga and emended description of the genus Gangjinia

A Gram-negative, strictly aerobic, pale-yellow pigmented, rod-shaped bacterium designated A4O-5^T was isolated from a red coloured marine alga (Chondrus ocellatus Holmes). Phylogenetic analyses based on the 16S rRNA gene sequence indicated that the new strain was affiliated with the family Flavobacteriaceae and shared approximately 90 % sequence similarity with Leptobacterium flavescens YM3-0301^T and Gangjinia marincola GJ16^T. The strain could be differentiated phenotypically from the related members of the family Flavobacteriaceae. The major fatty acids of strain A4O-5^T were identified as iso-C15:0, iso-C17:0 3-OH and summed feature 3 (C16:1 ω7c and/or C16:1 ω6c). A complex polar lipid profile was present consisting of phosphatidylethanolamine, an unidentified phospholipid, three unidentified amino lipids and an unidentified lipid. The DNA G+C content of the strain was determined to be 41.9 mol% and the major respiratory quinone was identified as menaquinone 6 (MK-6). From the distinct phylogenetic position and combination of genotypic and phenotypic characteristics, the strain is considered to represent a novel genus in the family Flavobacteriaceae, for which the name Citreitalea marina gen. nov., sp. nov. is proposed. The type strain of C. marina is A4O-5^T (=KCTC 32483^T=NBRC 109918^T).     

Spongiimonas flava gen. nov., sp. nov., a new member of the family Flavobacteriaceae isolated from an unidentified marine sponge

A Gram-negative, strictly aerobic, golden-yellow pigmented, non-motile, rod-shaped strain designated J36A-7^T was isolated from an unidentified yellow-green coloured marine sponge. Phylogenetic analyses based on the 16S rRNA gene sequence revealed that the novel isolate was affiliated with the family Flavobacteriaceae of the phylum Bacteroidetes and that it showed highest sequence similarity (85.6 %) to Nonlabens dokdonensis DSW-6^T. The strain could be differentiated phenotypically from recognized members of the family Flavobacteriaceae. The major fatty acids of strain J36A-7^T were identified as iso-C16:0, iso-C17:0 3-OH and summed feature three as defined by the MIDI system (C16:1 ω7c and/or iso-C15:0 2-OH). The DNA G+C content was determined to be 31.2 mol%, the major respiratory quinone was identified as menaquinone 6 (MK-6) and a complex polar lipid profile was present consisting of phosphatidylethanolamine, two unidentified glycolipids, one unidentified aminolipid and one unidentified lipid. From the distinct phylogenetic position and combination of genotypic and phenotypic characteristics, the strain is considered to represent a novel genus for which the name Spongiimonas flava gen. nov., sp. nov. is proposed. The type strain of S. flava is J36A-7^T (=KCTC 32176^T = NBRC 109319^T).     

Altuibacter lentus gen. nov., sp. nov., a novel member of family Flavobacteriaceae isolated from deep seawater of the South China Sea

A novel chemoheterotrophic, aerobic, Gram-negative, rod-shaped, yellow-pigmented, bacterial strain JLT2010^T was isolated from deep seawater of the South China Sea. Phylogenetic analysis based on the 16S rRNA gene sequences revealed that strain JLT2010^T belongs to the family Flavobacteriaceae and is most closely related to Ulvibacter antarcticus IMCC3101^T with 95.7 % similarity. Some phenotypic characteristics such as the absence of flexirubin-type pigments, growth at 37 °C, hydrolysis of casein differentiated strain JLT2010^T from the genus Ulvibacter as well as other genera in the family Flavobacteriaceae. The DNA G+C content of the strain JLT2010^T was found to be 35.7 mol% and the major respiratory quinone was found to be MK-6. On the basis of phenotypic and phylogenetic features, JLT2010^T is classified as a novel genus and species within the family Flavobacteriaceae, for which the name Altuibacter lentus gen. nov., sp. nov. is proposed. The type strain is JLT2010^T (=JCM 18884^T = CGMCC 1.12167^T).     

<Emphasis Type="Italic">Thalassorhabdus aurantiaca</Emphasis> gen. nov., sp. nov., a new member of the family <Emphasis Type="Italic">Flavobacteriaceae</Emphasis> isolated from seawater in South Korea

A novel Gram-negative, orange pigmented, strictly aerobic bacterium, designated strain IP9^T, was isolated from seawater at the sea shore of Incheon Eulwang-ri beach, South Korea. Cells of strain IP9^T were observed to be straight or slightly curved rods and colonies to be round and convex. Strain IP9^T was found to be catalase and oxidase positive, and non-motile. Growth was observed in the temperature range of 10–37 °C (optimum at 30 °C), pH range of 6–10 (optimum at pH 7–8) and salt concentration range of 0–7% (w/v) NaCl (optimum at 0–1%). On the basis of 16S rRNA gene sequence similarity and phylogenetic analysis, strain IP9^T was found to be related to the members of the family Flavobacteriaceae, being closely related to Hwangdonia seohaensis KCTC 32177^T (95.3% sequence similarity). The DNA G?+?C content of the novel strain was determined to be 39.1 mol%. The major polar lipids were found to be phosphatidylethanolamine, three unidentified aminoglycolipids and two unidentified glycolipids. The major fatty acids (>?10%) were identified as iso-C_15:0 and iso-C_17:0 3-OH. The predominant quinone was found to be menaquinone 6 (MK-6). Based on the biochemical, phylogenetic and physiological data, we conclude that strain IP9^T (=?KCTC 52523^T?=?JCM 31732^T) represents the type species of a novel genus of the family Flavobacteriaceae for which the name Thalassorhabdus aurantiaca gen. nov., sp. nov. is proposed.     

<Emphasis Type="Italic">Algoriella xinjiangensis</Emphasis> gen. nov., sp. nov., a new psychrotolerant bacterium of the family <Emphasis Type="Italic">Flavobacteriaceae</Emphasis>

An aerobic, Gram-stain negative, non-spore-forming and psychrotolerant bacterium, designated strain XJ109^T, was isolated from a sewage water sample collected from Xinjiang Uigur Autonomous Region, China. Phylogenetic analysis based on 16S rRNA gene sequence indicated that strain XJ109^T represents a novel member of the family Flavobacteriaceae. The strain showed 95.5 % similarity with the 16S rRNA gene sequence of Empedobacter brevis LMG 4011^T, 95.4 % with Chishuiella changwenlii BY4^T, 95.3 % with Empedobacter falsenii NF 993^T and 92.3 % with Weeksella virosa DSM 16922^T. Strain XJ109^T showed the common phenotypic and chemotaxonomic characteristics of the family Flavobacteriaceae, containing menaquinone-6 (MK-6) as the predominant respiratory quinone and iso-C_17:0 3OH and iso-C_15:0 as the major fatty acids. The polar lipid profile consisted of phosphatidylethanolamine, one unidentified phospholipid and two unidentified lipids. The genomic DNA G+C content was 38.0 mol%. Strain XJ109^T was positive for catalase and oxidase activities, and it was observed to grow at 4–30 °C (optimal 16–20 °C), pH 6.5–10.0 (optimal 7.0–7.5) and in media containing 0–2.0 % (w/v) NaCl (optimal 0.5 %). On the basis of the polyphasic evidence presented, strain XJ109^T is considered to represent a novel genus and species of the family Flavobacteriaceae, for which the name Algoriella xinjiangensis gen. nov., sp. nov. is proposed. The type strain is XJ109^T (=CGMCC 1.10229^T=JCM 16590^T).     

Cruoricaptor ignavus gen. nov., sp. nov., a novel bacterium of the family Flavobacteriaceae isolated from blood culture of a man with bacteraemia

A Gram-reaction-negative bacterium, strain IMMIB L-12475^T, was isolated from blood cultures of a human with septicaemia. The yellowish orange pigmented strain contained flexirubin pigment. Phylogenetic analysis based on 16S rRNA gene sequence revealed that strain IMMIB L-12475^T belonged to the family Flavobacteriaceae, forming a distinct phyletic line that is distantly related (79.1–89.4% sequence similarity) to described genera of this family. Membership to the family was confirmed by a fatty acid profile consisting of branched-chain and 3-hydroxy fatty acids with major amounts of iso-C_17:0 3-OH and iso-C_15:0, by the presence of menaquinone MK-6 as the only respiratory quinone and a polyamine pattern that contained sym-homospermidine as major component. The phospholipids consisted of phosphatidylethanolamine and an unknown phospholipid. The genomic DNA mol% G+C content was 45.6%. The distant phylogenetic position as compared to other representative of the family and the significant phenotypic properties such as pigment composition, morphology, and physiology support the proposal of a novel genus and species Cruoricaptor ignavus gen. nov., sp. nov. The type strain is IMMIB L-12475^T (=DSM 25479^T = CCUG 62025^T).     

<Emphasis Type="Italic">Zunongwangia flava</Emphasis> sp. nov., belonging to the family <Emphasis Type="Italic">Flavobacteriaceae</Emphasis>, isolated from <Emphasis Type="Italic">Salicornia europaea</Emphasis>

A yellow pigmented bacterium designated strain MBLN094^T within the family Flavobacteriaceae was isolated from a halophyte Salicornia europaea on the coast of the Yellow Sea. This strain was a Gram-stain negative, aerobic, non-spore forming, rod-shaped bacterium. Phylogenetic analysis of the 16S rRNA gene sequence of strain MBLN094^T was found to be related to the genus Zunongwangia, exhibiting 16S rRNA gene sequence similarity values of 97.0, 96.8, 96.4, and 96.3% to Zunongwangia mangrovi P2E16^T, Z. profunda SM-A87^T, Z. atlantica 22II14-10F7^T, and Z. endophytica CPA58^T, respectively. Strain MBLN094^T grew at 20?37°C (optimum, 25?30°C), at pH 6.0?10.0 (optimum, 7.0?8.0), and with 0.5?15.0% (w/v) NaCl (optimum, 2.0?5.0%). Menaquinone MK-6 was the sole respiratory quinone. The polar lipids were phosphatidylethanolamine, two unidentified aminolipids, and four unidentified lipids. Major fatty acids were iso-C_17:0 3-OH, summed feature 3 (C_16:1ω6c and/or C16:1 ω7c), and iso-C_15:0. The genomic DNA G + C content was 37.4 mol%. Based on these polyphasic taxonomic data, strain MBLN094^T is considered to represent a novel species of the genus Zunongwangia, for which the name Zunongwangia flava sp. nov. is proposed. The type strain is MBLN094^T (= KCTC 62279^T = JCM 32262^T).     

Chryseobacterium yeoncheonense sp. nov., with ginsenoside converting activity isolated from soil of a ginseng field

A Gram-staining negative, aerobic, non-motile, non-flagellate, yellow-pigmented, rod-shaped bacterial strain, designated strain DCY67^T, was isolated from ginseng field in Republic of Korea. Strain DCY67^T contained β-glucosidase activity which converts ginsenoside Rb1 to compound K. Optimum growth of DCY67^T occurred at 30 °C and pH 6.0–6.5. Analysis of the 16S rRNA gene sequences revealed that strain DCY67^T belonged to the family Flavobacteriaceae and was most closely related to Chryseobacterium ginsenosidimutans THG 15^T (97.5 %). The genomic DNA G+C content was 36.1 mol%. The predominant quinones were MK-6 (90.9 %) and MK-7 (9.15 %). The major fatty acids were iso-C_15:0, summed feature 3 (containing C_16:1 ω7c and/or C_16:1 ω6c) and iso-C_17:0 3-OH. On the basis of these phenotypic, genotypic and chemotaxonomic studies, strain DCY67^T represents a novel species of the genus Chryseobacterium, for which, name Chryseobacterium yeoncheonense sp. nov. proposed the type strain is DCY67^T (=KCTC 32090^T = JCM 18516^T).     

Identification of a novel carotenoid, 2′-isopentenylsaproxanthin,by Jejuia pallidilutea strain 11shimoA1 and its increased production under alkaline condition

Carotenoids are a class of naturally occurring pigment, carrying out important biological functions in photosynthesis and involved in environmental responses including nutrition in organisms. Saproxanthin and myxol, which have monocyclic carotenoids with a γ-carotene skeleton, have been reported to show a stronger antioxidant activity than those with β-carotene and zeaxanthin. In this research, a yellow-orange bacterium of strain 11shimoA1 (JCM19538) was isolated from a seaweed collected at Nabeta Bay (Shizuoka, Japan). The 16S rRNA gene sequence of strain 11shimoA1 revealed more than 99.99 % similarity with those of Jejuia pallidilutea strains in the family Flavobacteriaceae. Strain 11shimoA1 synthesized two types of carotenoids. One of them was (3R, 3’R)-zeaxanthin with dicyclic structure and another was identified as (3R, 2’S)-2′-isopentenylsaproxanthin, a novel monocyclic carotenoid with pentenyl residue at C-2′ position of saproxanthin, using FAB-MS, ¹H NMR, and CD analyses. Culturing strain 11shimoA1 in an alkaline medium at pH 9.2 resulted in a markedly increased in production of 2′-isopentenylsaproxanthin per dry cell weight, but a decreased in zeaxanthin production as compared to their respective production levels in medium with pH 7.0. These carotenoids are likely to play some roles in the adaptation of the bacterium to the environmental conditions.     

Structural analysis of coxsackievirus A7 reveals conformational changes associated with uncoating

Coxsackievirus A7 (CAV7) is a rarely detected and poorly characterized serotype of the Enterovirus species Human enterovirus A (HEV-A) within the Picornaviridae family. The CAV7-USSR strain has caused polio-like epidemics and was originally thought to represent the fourth poliovirus type, but later evidence linked this strain to the CAV7-Parker prototype. Another isolate, CAV7-275/58, was also serologically similar to Parker but was noninfectious in a mouse model. Sequencing of the genomic region encoding the capsid proteins of the USSR and 275/58 strains and subsequent comparison with the corresponding amino acid sequences of the Parker strain revealed that the Parker and USSR strains are nearly identical, while the 275/58 strain is more distant. Using electron cryomicroscopy and three-dimensional image reconstruction, the structures of the CAV7-USSR virion and empty capsid were resolved to 8.2-Å and 6.1-Å resolutions, respectively. This is one of the first detailed structural analyses of the HEV-A species. Using homology modeling, reconstruction segmentation, and flexible fitting, we constructed a pseudoatomic T = 1 (pseudo T = 3) model incorporating the three major capsid proteins (VP1 to VP3), addressed the conformational changes of the capsid and its constituent viral proteins occurring during RNA release, and mapped the capsid proteins'' variable regions to the structure. During uncoating, VP4 and RNA are released analogously to poliovirus 1, the interfaces of VP2 and VP3 are rearranged, and VP1 rotates. Variable regions in the capsid proteins were predicted to map mainly to the surface of VP1 and are thus likely to affect the tropism and pathogenicity of CAV7.     

Genome characteristics of the proteorhodopsin-containing marine flavobacterium <Emphasis Type="Italic">Polaribacter dokdonensis</Emphasis> DSW-5

Bacteria in the genus Polaribacter, belonging to the family Flavobacteriaceae, are typically isolated from marine environments. Polaribacter dokdonensis DSW-5, the type strain of the species, is a Gram-negative bacterium isolated from the East Sea of Korea. Whole genome shotgun sequencing was performed with the HiSeq 2000 platform and paired-end reads were generated at 188-fold coverage. The sequencing reads were assembled into two contigs with a total length of 3.08 Mb. The genome sequences of DSW-5 contain 2,776 proteincoding sequences and 41 RNA genes. Comparison of average nucleotide identities among six available Polaribacteria genomes including DSW-5 suggested that the DSW-5 genome is most similar to that of Polaribacter sp. MED152, which is a proteorhodopsin-containing marine bacterium. A phylogenomic analysis of the six Polaribacter strains and 245 Flavobacteriaceae bacteria confirmed a close relationship of the genus Polaribacter with Tenacibaculum and Kordia. DSW-5’s genome has a gene encoding proteorhodopsin and genes encoding 85 enzymes belonging to carbohydrate-active enzyme families and involved in polysaccharide degradation, which may play important roles in energy metabolism of the bacterium in the marine ecosystem. With genes for 238 CAZymes and 203 peptidases, DSW-5 has a relatively high number of degrading enzymes for its genome size suggesting its characteristics as a free-living marine heterotroph.     

Genome-Wide Identification,Classification, and Expression Analysis of 14-3-3 Gene Family in Populus

Background

In plants, 14-3-3 proteins are encoded by a large multigene family and are involved in signaling pathways to regulate plant development and protection from stress. Although twelve Populus 14-3-3s were identified based on the Populus trichocarpa genome V1.1 in a previous study, no systematic analysis including genome organization, gene structure, duplication relationship, evolutionary analysis and expression compendium has been conducted in Populus based on the latest P. trichocarpa genome V3.0.

Principal Findings

Here, a comprehensive analysis of Populus 14-3-3 family is presented. Two new 14-3-3 genes were identified based on the latest P. trichocarpa genome. In P. trichocarpa, fourteen 14-3-3 genes were grouped into ε and non-ε group. Exon-intron organizations of Populus 14-3-3s are highly conserved within the same group. Genomic organization analysis indicated that purifying selection plays a pivotal role in the retention and maintenance of Populus 14-3-3 family. Protein conformational analysis indicated that Populus 14-3-3 consists of a bundle of nine α-helices (α1-α9); the first four are essential for formation of the dimer, while α3, α5, α7, and α9 form a conserved peptide-binding groove. In addition, α1, α3, α5, α7, and α9 were evolving at a lower rate, while α2, α4, and α6 were evolving at a relatively faster rate. Microarray analyses showed that most Populus 14-3-3s are differentially expressed across tissues and upon exposure to various stresses.

Conclusions

The gene structures and their coding protein structures of Populus 14-3-3s are highly conserved among group members, suggesting that members of the same group might also have conserved functions. Microarray and qRT-PCR analyses showed that most Populus 14-3-3s were differentially expressed in various tissues and were induced by various stresses. Our investigation provided a better understanding of the complexity of the 14-3-3 gene family in poplars.     

Nonlabens marina sp. nov., a novel member of the Flavobacteriaceae isolated from the Pacific Ocean

Two aerobic, Gram-negative, orange pigmented and irregular rod-shaped bacteria, designated S1-05 and S1-08^T, were isolated from seawater from the Pacific Ocean. Phylogenetic analysis based on their 16S rRNA gene sequences revealed that the novel isolates could be affiliated with the genus Nonlabens of the family Flavobacteriaceae. The strains S1-05 and S1-08^T shared 100 % pairwise sequences similarity with each other and showed less than 96.8 % similarity with the cultivated members of the genus Nonlabens. The novel isolates are phenotypically and physiologically different from strains described previously. The strains were found to be non-motile, oxidase positive, catalase positive and hydrolyzed gelatin and aesculin. The G+C contents of the DNA were determined to 41.4 and 41.7 mol% and MK-6 the predominant menaquinone. Anteiso-C15:0 and iso-C15:0 were found to be the major two cellular fatty acids. On the basis of polyphasic taxonomic studies, it was concluded that strains S1-05 and S1-08^T represent a novel species within the genus Nonlabens, for which the name Nonlabens marina sp. nov. is proposed. The type strain of N. marina is S1-08^T (=KCTC 23432^T = NBRC 107738^T).     

Polaribacter reichenbachii sp. nov.: A New Marine Bacterium Associated with the Green Alga Ulva fenestrata

A Gram-negative, aerobic, rod-shaped, motile by gliding and yellow-pigmented bacterium, designated strain 6Alg 8^T, was isolated from the common Pacific green alga Ulva fenestrata. The phylogenetic analysis based on 16S rRNA gene sequence placed the novel strain within the genus Polaribacter, a member of the family Flavobacteriaceae, the phylum Bacteroidetes, with sequence similarities of 97.6 % to Polaribacter dokdonensis DSW-5^T and 92.8–96.1 % to other recognized Polaribacter species. The prevalent fatty acids of strain 6Alg 8^T were iso-C_15:0, iso-C_15:1, iso-C_15:0 2-OH, C_15:0 and C_15:1ω6. The polar lipid profile consisted of the major lipids phosphatidylethanolamine, two unknown aminolipids and one unknown lipid. The DNA G+C content of the type strain is 31.6 mol%. The new isolate and the type strains of recognized species of the genus Polaribacter were readily distinguished based on a number of phenotypic characteristics. A combination of the genotypic and phenotypic data showed that the algal isolate represents a novel species of the genus Polaribacter, for which the name Polaribacter reichenbachii sp. nov. is proposed. The type strain is 6Alg 8^T (= KCTC 23969^T = KMM 6386^T = LMG 26443^T).     

Complete Genome Sequence of Croceibacter atlanticus HTCC2559T

Here we announce the complete genome sequence of Croceibacter atlanticus HTCC2559^T, which was isolated by high-throughput dilution-to-extinction culturing from the Bermuda Atlantic Time Series station in the Western Sargasso Sea. Strain HTCC2559^T contained genes for carotenoid biosynthesis, flavonoid biosynthesis, and several macromolecule-degrading enzymes. The genome confirmed physiological observations of cultivated Croceibacter atlanticus strain HTCC2559^T, which identified it as an obligate chemoheterotroph.The phylum Bacteroidetes comprises 6 to ∼30% of total bacterial communities in the ocean by fluorescence in situ hybridization (8-10). Most marine Bacteroidetes are in the family Flavobacteriaceae, most of which are aerobic respiratory heterotrophs that form a well-defined clade by 16S rRNA phylogenetic analyses (4). The members of this family are well known for degrading macromolecules, including chitin, DNA, cellulose, starch, and pectin (17), suggesting their environmental roles as detritus decomposers in the ocean (6). Marine Polaribacter and Dokdonia species in the Flavobacteriaceae have also shown to have photoheterotrophic metabolism mediated by proteorhodopsins (11, 12).Several strains of the family Flavobacteriaceae were isolated from the Sargasso Sea and Oregon coast, using high-throughput culturing approaches (7). Croceibacter atlanticus HTCC2559^T was cultivated from seawater collected at a depth of 250 m from the Sargasso Sea and was identified as a new genus in the family Flavobacteriaceae based on its 16S rRNA gene sequence similarities (6). Strain HTCC2559^T met the minimal standards for genera of the family Flavobacteriaceae (3) on the basis of phenotypic characteristics (6).Here we report the complete genome sequence of Croceibacter atlanticus HTCC2559^T. The genome sequencing was initiated by the J. Craig Venter Institute as a part of the Moore Foundation Microbial Genome Sequencing Project and completed in the current announcement. Gaps among contigs were closed by Genotech Co., Ltd. (Daejeon, Korea), using direct sequencing of combinatorial PCR products (16). The HTCC2559^T genome was analyzed with a genome annotation system based on GenDB (14) at Oregon State University and with the NCBI Prokaryotic Genomes Automatic Annotation Pipeline (15, 16).The HTCC2559^T genome is 2,952,962 bp long, with 33.9 mol% G+C content, and there was no evidence of plasmids. The number of protein-coding genes was 2,715; there were two copies of the 16S-23S-5S rRNA operon and 36 tRNA genes. The HTCC2559^T genome contained genes for a complete tricarboxylic acid cycle, glycolysis, and a pentose phosphate pathway. The genome also contained sets of genes for metabolic enzymes involved in carotenoid biosynthesis and also a serine/glycine hydroxymethyltransferase, which is often associated with the assimilatory serine cycle (13). The potential for HTCC2559^T to use bacterial type III polyketide synthase (PKS) needs to be confirmed because this organism had a naringenin-chalcone synthase (CHS) or chalcone synthase (EC 2.3.1.74), a key enzyme in flavonoid biosynthesis. CHS initiates the addition of three molecules of malonyl coenzyme A (malonyl-CoA) to a starter CoA ester (e.g., 4-coumaroyl-CoA) (1) and takes part in a few bacterial type III polyketide synthase systems (1, 2, 5, 18).The complete genome sequence confirmed that strain HTCC2559^T is an obligate chemoheterotroph because no genes for phototrophy were found. As expected from physiological characteristics (6), the HTCC2559^T genome contained a set of genes coding for enzymes required to degrade high-molecular-weight compounds, including peptidases, metallo-/serine proteases, pectinase, alginate lyases, and α-amylase.     

<Emphasis Type="Italic">Ascidiaceibacter salegens</Emphasis> gen. nov., sp. nov., isolated from an ascidian

An aerobic, Gram-stain negative, rod-shaped, non-motile bacterium, designated as strain HQA918^T, was isolated from an ascidian, Botryllus schlosseri, which was collected from the coast of Weihai in the north of the Yellow Sea, in China. The strain grew optimally at 28–30 °C, at pH values 7.0–8.0, and in the presence of 1.0–3.0% (w/v) sodium chloride (NaCl). A phylogenetic analysis based on 16S rRNA gene sequences showed that strain HQA918^T can be affiliated with the family Flavobacteriaceae in the phylum Bacteroidetes, with 92.7% similarity to its close relatives. The major fatty acids identified were iso-C_15:0, iso-C_15:0 3-OH, and summed feature 3 (iso-C_15:0 2-OH and/or C_16:1ω7c). The major polar lipids were phosphatidylethanolamine, one unidentified aminolipid, and five unidentified polar lipids. The G+C content of the genomic DNA was 44.1 mol%. On the basis of the phylogenetic, genotypic, phenotypic, and chemotaxonomic data, this organism should be classified as a representative of a novel genus, for which the name Ascidiaceibacter gen. nov. is proposed. The type species is Ascidiaceibacter salegens sp. nov. (type strain HQA918^T?=?KCTC 52719^T?=?MCCC 1K03259^T).     

ISRm4-1 and ISRm9, two novel insertion sequences from Sinorhizobium meliloti

Two novel insertion sequences, ISRm4-1 and ISRm9 have been identified in Sinorhizobium meliloti. ISRm4-1 is 936-bp in length, flanked by 17-bp putative terminal inverted repeats and a putative target duplication of 3-bp. ISRm4-1 is a member of the IS5 family of insertion sequences, closely related to ISRm4. ISRm9 is 2797-bp in length and carries 25-bp inverted repeats with target duplication of 7-bp. ISRm9 belongs to the IS21 family of insertion elements. On the non-pSym plasmid pRmeGR4b from S. meliloti strain GR4, a copy of ISRm4-1 is interrupted at nucleotide 150 from its 5′-end by a copy of ISRm9. Whereas ISRm4-like elements are widespread in S. meliloti, the distribution of ISRm9 appears to be correlated to that of pRmeGR4b-type plasmids.     

Changes in Bacterioplankton Composition under Different Phytoplankton Regimens

The results of empirical studies have revealed links between phytoplankton and bacterioplankton, such as the frequent correlation between chlorophyll a and bulk bacterial abundance and production. Nevertheless, little is known about possible links at the level of specific taxonomic groups. To investigate this issue, seawater microcosm experiments were performed in the northwestern Mediterranean Sea. Turbulence was used as a noninvasive means to induce phytoplankton blooms dominated by different algae. Microcosms exposed to turbulence became dominated by diatoms, while small phytoflagellates gained importance under still conditions. Denaturing gradient gel electrophoresis (DGGE) of 16S rRNA gene fragments showed that changes in phytoplankton community composition were followed by shifts in bacterioplankton community composition, both as changes in the presence or absence of distinct bacterial phylotypes and as differences in the relative abundance of ubiquitous phylotypes. Sequencing of DGGE bands showed that four Roseobacter phylotypes were present in all microcosms. The microcosms with a higher proportion of phytoflagellates were characterized by four phylotypes of the Bacteroidetes phylum: two affiliated with the family Cryomorphaceae and two with the family Flavobacteriaceae. Two other Flavobacteriaceae phylotypes were characteristic of the diatom-dominated microcosms, together with one Alphaproteobacteria phylotype (Roseobacter) and one Gammaproteobacteria phylotype (Methylophaga). Phylogenetic analyses of published Bacteroidetes 16S rRNA gene sequences confirmed that members of the Flavobacteriaceae are remarkably responsive to phytoplankton blooms, indicating these bacteria could be particularly important in the processing of organic matter during such events. Our data suggest that quantitative and qualitative differences in phytoplankton species composition may lead to pronounced differences in bacterioplankton species composition.