Complete genome sequence of pectin-degrading Flavobacteriaceae bacterium GSB9.

Pectic oligosaccharides, which are considered to be potential prebiotics, may be generated by pectin-degrading enzymes. Here, we report the complete genome sequence of the pectin-degrading marine bacterium, Flavobacteriaceae bacterium GSB9, which was isolated from seawater of South Korea. The complete genome sequence revealed that the chromosome was 3,630,376 bp in size, had a G + C content of 36.6 mol%, and was predicted to encode 3100 protein-coding sequences (CDSs), 40 tRNAs, and six 16S-23S-5S rRNAs. Genome sequence analysis revealed that this strain possesses multiple genes predicted to encode pectin-degrading enzymes. Our analysis may facilitate the future application of this strain against pectin in various industries.

Phylogenomic Analyses of a Clade Within the Family Flavobacteriaceae Suggest Taxonomic Reassignments of Species of the Genera Algibacter, Hyunsoonleella, Jejuia, and Flavivirga, and the Proposal of Pseudalgibacter gen. nov. and Pseudalgibacter alginicilyticus comb. nov.

The family Flavobacteriaceae forms a major branch within the phylum Bacteroidetes. Whole-genome sequence-based analysis could significantly improve the accuracy of taxonomic assignments. In this study, phylogenomic analyses were carried out to revisit the taxonomic status of a clade of the family Flavobacteriaceae. Taking genome-based phylogeny as the primary guideline and average amino acid identity and phenotypic information as supplements, the following taxonomic proposals were put forward: Arenitalea lutea should be reclassified into the genus Algibacter; Algibacter aquaticus should be reclassified into the genus Flavivirga; Jejuia pallidilutea and Algibacter aestuarii should be reclassified into the genus Hyunsoonleella; Algibacter alginicilyticus should be reclassified into the novel genus Pseudalgibacter gen. nov. This study builds up a solid framework for taxonomic decisions of a clade of the family Flavobacteriaceae and will contribute to further insights into the evolution of this family.

Dynamic bacterial community response to Akashiwo sanguinea (Dinophyceae) bloom in indoor marine microcosms.

We investigated the dynamics of the bacterial composition and metabolic function within Akashiwo sanguinea bloom using a 100-L indoor microcosm and metagenomic next-generation sequencing. We found that the bacterial community was classified into three groups at 54% similarity. Group I was associated with "during the A. sanguinea bloom stage" and mainly consisted of Alphaproteobacteria, Flavobacteriia and Gammaproteobacteria. Meanwhile, groups II and III were associated with the "late bloom/decline stage to post-bloom stage" with decreased Flavobacteriia and Gammaproteobacteria in these stages. Upon the termination of the A. sanguinea bloom, the concentrations of inorganic nutrients (particularly PO43-, NH4+ and dissolved organic carbon) increased rapidly and then decreased. From the network analysis, we found that the A. sanguinea node is associated with certain bacteria. After the bloom, the specific increases in NH4+ and PO43- nodes are associated with other bacterial taxa. The changes in the functional groups of the bacterial community from chemoheterotrophy to nitrogen association metabolisms were consistent with the environmental impacts during and after A. sanguinea bloom. Consequently, certain bacterial communities and the environments dynamically changed during and after harmful algal blooms and a rapid turnover within the bacterial community and their function can respond to ecological interactions.

Repeated evolutionary transitions of flavobacteria from marine to non-marine habitats.

The taxonomy of marine and non-marine organisms rarely overlap, but the mechanisms underlying this distinction are often unknown. Here, we predicted three major ocean-to-land transitions in the evolutionary history of Flavobacteriaceae, a family known for polysaccharide and peptide degradation. These unidirectional transitions were associated with repeated losses of marine signature genes and repeated gains of non-marine adaptive genes. This included various Na+ -dependent transporters, osmolyte transporters and glycoside hydrolases (GH) for sulfated polysaccharide utilization in marine descendants, and in non-marine descendants genes for utilizing the land plant material pectin and genes facilitating terrestrial host interactions. The K+ scavenging ATPase was repeatedly gained whereas the corresponding low-affinity transporter repeatedly lost upon transitions, reflecting K+ ions are less available to non-marine bacteria. Strikingly, the central metabolism Na+ -translocating NADH: quinone dehydrogenase gene was repeatedly gained in marine descendants, whereas the H+ -translocating counterpart was repeatedly gained in non-marine lineages. Furthermore, GH genes were depleted in isolates colonizing animal hosts but abundant in bacteria inhabiting other non-marine niches; thus relative abundances of GH versus peptidase genes among Flavobacteriaceae lineages were inconsistent with the marine versus non-marine dichotomy. We suggest that phylogenomic analyses can cast novel light on mechanisms explaining the distribution and ecology of key microbiome components.

Complete genome sequence of Maribacter sp. T28, a polysaccharide-degrading marine flavobacteria.

The degradation of plant polysaccharides by enzymes is an industry of increasing importance. Here we present the complete genome sequence of a marine flavobacteria, Maribacter sp. T28 (=CGMCC 1.15788). The genome comprises 4,271,158bp in a circular chromosome with a G+C content of 34.4% and contains genes encoding xylanolytic, alginolytic and pectinolytic enzymes. Genes encoding alginate lyases and a pectin degradation protein (kdgF) are located on a polysaccharide utilization locus. Maribacter sp. T28 has the ability to utilize xylan, alginate and pectin for growth. The key degradation products xylose and 2-keto-3- deoxy-gluconate were detected from xylan and pectin, respectively. The Maribacter species genomes provide genetic information regarding polysaccharide-degrading enzymes.

Enhanced crude oil biodegradative potential of natural phytoplankton-associated hydrocarbonoclastic bacteria.

Phytoplankton have been shown to harbour a diversity of hydrocarbonoclastic bacteria (HCB), yet it is not understood how these phytoplankton-associated HCB would respond in the event of an oil spill at sea. Here, we assess the diversity and dynamics of the bacterial community associated with a natural population of marine phytoplankton under oil spill-simulated conditions, and compare it to that of the free-living (non phytoplankton-associated) bacterial community. While the crude oil severely impacted the phytoplankton population and was likely conducive to marine oil snow formation, analysis of the MiSeq-derived 16S rRNA data revealed dramatic and differential shifts in the oil-amended communities that included blooms of recognized HCB (e.g., Thalassospira, Cycloclasticus), including putative novel phyla, as well as other groups with previously unqualified oil-degrading potential (Olleya, Winogradskyella, and members of the inconspicuous BD7-3 phylum). Notably, the oil biodegradation potential of the phytoplankton-associated community exceeded that of the free-living community, and it showed a preference to degrade substituted and non-substituted polycyclic aromatic hydrocarbons. Our study provides evidence of compartmentalization of hydrocarbon-degrading capacity in the marine water column, wherein HCB associated with phytoplankton are better tuned to degrading crude oil hydrocarbons than that by the community of planktonic free-living bacteria.

Real-time PCR assay for Aquimarina macrocephali subsp. homaria and its distribution in shell disease lesions of Homarus americanus, Milne-Edwards, 1837, and environmental samples.

Epizootic shell disease (ESD) is causing major losses to the lobster fishery in southern New England. Potential pathogens have been identified in lesion communities, but there are currently no efficient means of detecting and quantifying their presence. A qPCR assay was developed for a key potential pathogen, Aquimarina macrocephali subsp. homaria found to be ubiquitous in ESD lesions but not the unaffected integument. Application of the assay to various samples demonstrated that A. macrocephali subsp. homaria is ubiquitous and abundant in lobster lesions, commonly associated with healthy surfaces of crabs and is scarce in water and sediment samples from southern New England suggesting the affinity of this microorganism to the Arthropod integument. The qPCR assay developed here can be applied in future in vivo and in vitro studies to better understand the ecology and role of A. macrocephali subsp.homaria. in shell disease.

Cloacibacterium caeni sp. nov., isolated from activated sludge.

A Gram-stain-negative, facultatively anaerobic bacterium, designated B6T, was isolated from activated sludge of a wastewater treatment plant in South Korea. Cells were oxidase- and catalase-positive and non-motile rods producing yellow carotenoid-type pigments. Growth of B6T was observed at 20-40 °C (optimum, 37 °C) and pH 6.6-8.2 (optimum, pH 7.0) and in R2A broth supplemented with 0-1 % (w/v) NaCl (optimum, 0 %). B6T contained iso-C15 : 0 as the major fatty acid. Menaquinone-6 was detected as the sole respiratory quinone. The G+C content of the genomic DNA of B6T was 31.5 mol%. The results of phylogenetic analysis based on 16S rRNA gene sequences indicated that B6T formed a tight phylogenetic lineage with members of the genus Cloacibacterium. B6T was most closely related to Cloacibacterium rupense R2A-16T (99.0 %), Cloacibacterium normanense NRS1T (98.7 %) and Cloacibacterium haliotis WB5T (97.4 %), but their DNA-DNA relatedness levels were less than 42.0 %. On the basis of phenotypic, chemotaxonomic and molecular properties, it is clear that B6T represents a novel species of the genus Cloacibacterium, for which the name Cloacibacterium caeni sp. nov. is proposed. The type strain is B6T (=KACC 18988T=JCM 31714T).

Hydrocarbon biodegradation by Arctic sea-ice and sub-ice microbial communities during microcosm experiments, Northwest Passage (Nunavut, Canada).

The increasing accessibility to navigation and offshore oil exploration brings risks of hydrocarbon releases in Arctic waters. Bioremediation of hydrocarbons is a promising mitigation strategy but challenges remain, particularly due to low microbial metabolic rates in cold, ice-covered seas. Hydrocarbon degradation potential of ice-associated microbes collected from the Northwest Passage was investigated. Microcosm incubations were run for 15 days at -1.7°C with and without oil to determine the effects of hydrocarbon exposure on microbial abundance, diversity and activity, and to estimate component-specific hydrocarbon loss. Diversity was assessed with automated ribosomal intergenic spacer analysis and Ion Torrent 16S rRNA gene sequencing. Bacterial activity was measured by (3)H-leucine uptake rates. After incubation, sub-ice and sea-ice communities degraded 94% and 48% of the initial hydrocarbons, respectively. Hydrocarbon exposure changed the composition of sea-ice and sub-ice communities; in sea-ice microcosms, Bacteroidetes (mainly Polaribacter) dominated whereas in sub-ice microcosms, the contribution of Epsilonproteobacteria increased, and that of Alphaproteobacteria and Bacteroidetes decreased. Sequencing data revealed a decline in diversity and increases in Colwellia and Moritella in oil-treated microcosms. Low concentration of dissolved organic matter (DOM) in sub-ice seawater may explain higher hydrocarbon degradation when compared to sea ice, where DOM was abundant and composed of labile exopolysaccharides.

Lutibacter profundi sp. nov., isolated from a deep-sea hydrothermal system on the Arctic Mid-Ocean Ridge and emended description of the genus Lutibacter.

A bacterial strain designated LP1T was isolated from a microbial mat growing on the surface of a black smoker chimney at the Loki's Castle hydrothermal system, which is located on the Arctic Mid-Ocean Ridge. Phylogenetic analyses based on 16S rRNA gene sequences positioned strain LP1T within the family Flavobacteriaceae with Lutibacterholmesii as the closest relative (97.5 % 16S rRNA gene sequence similarity). Strain LP1T was rod-shaped, Gram-reaction-negative and non-motile. It grew in a modified artificial seawater medium supplemented with tryptone and vitamins at pH 5.5-7.5 (optimum pH 6.0-6.5), within a temperature range of 13-34 °C (optimum 23 °C), and under microaerobic conditions. The most abundant fatty acids (>10 %) were iso-C15 : 0 (25.2 %) and iso-C15 : 0 3-OH (14.5 %). The genome of strain LP1T has a DNA G+C content of 29.8 mol%. Based on the results of the polyphasic characterization presented here, strain LP1T is considered to represent a novel species of the genus Lutibacter, for which the name Lutibacter profundi sp. nov. is proposed. The type strain is LP1T (=DSM 100437T =JCM 30585T). An emended description of the genus Lutibacter is also provided to fit the description of strain LP1T.

Dietary ß-glucan (MacroGard®) enhances survival of first feeding turbot (Scophthalmus maximus) larvae by altering immunity, metabolism and microbiota.

Reflecting the natural biology of mass spawning fish aquaculture production of fish larvae is often hampered by high and unpredictable mortality rates. The present study aimed to enhance larval performance and immunity via the oral administration of an immunomodulator, ß-glucan (MacroGard(®)) in turbot (Scophthalmus maximus). Rotifers (Brachionus plicatilis) were incubated with or without yeast ß-1,3/1,6-glucan in form of MacroGard(®) at a concentration of 0.5 g/L. Rotifers were fed to first feeding turbot larvae once a day. From day 13 dph onwards all tanks were additionally fed untreated Artemia sp. nauplii (1 nauplius ml/L). Daily mortality was monitored and larvae were sampled at 11 and 24 dph for expression of 30 genes, microbiota analysis, trypsin activity and size measurements. Along with the feeding of ß-glucan daily mortality was significantly reduced by ca. 15% and an alteration of the larval microbiota was observed. At 11 dph gene expression of trypsin and chymotrypsin was elevated in the MacroGard(®) fed fish, which resulted in heightened tryptic enzyme activity. No effect on genes encoding antioxidative proteins was observed, whilst the immune response was clearly modulated by ß-glucan. At 11 dph complement component c3 was elevated whilst cytokines, antimicrobial peptides, toll like receptor 3 and heat shock protein 70 were not affected. At the later time point (24 dph) an anti-inflammatory effect in form of a down-regulation of hsp 70, tnf-α and il-1ß was observed. We conclude that the administration of MacroGard(®) induced an immunomodulatory response and could be used as an effective measure to increase survival in rearing of turbot.

Multidrug Resistance in Quinolone-Resistant Gram-Negative Bacteria Isolated from Hospital Effluent and the Municipal Wastewater Treatment Plant.

This study is aimed to assess if hospital effluents represent an important supplier of multidrug-resistant (MDR) Gram-negative bacteria that, being discharged in the municipal collector, may be disseminated in the environment and bypassed in water quality control systems. From a set of 101 non-Escherichia coli Gram-negative bacteria with reduced susceptibility to quinolones, was selected a group of isolates comprised by those with the highest indices of MDR (defined as nonsusceptibility to at least one agent in six or more antimicrobial categories, MDR ≥6) or resistance to meropenem or ceftazidime (n = 25). The isolates were identified and characterized for antibiotic resistance phenotype, plasmid-mediated quinolone resistance (PMQR) genes, and other genetic elements and conjugative capacity. The isolates with highest MDR indices were mainly from hospital effluent and comprised ubiquitous bacterial groups of the class Gammaproteobacteria, of the genera Aeromonas, Acinetobacter, Citrobacter, Enterobacter, Klebsiella, and Pseudomonas, and of the class Flavobacteriia, of the genera Chryseobacterium and Myroides. In this group of 25 strains, 19 identified as Gammaproteobacteria harbored at least one PMQR gene (aac(6')-Ib-cr, qnrB, qnrS, or oqxAB) or a class 1 integron gene cassette encoding aminoglycoside, sulfonamide, or carbapenem resistance. Most of the E. coli J53 transconjugants with acquired antibiotic resistance resulted from conjugation with Enterobacteriaceae. These transconjugants demonstrated acquired resistance to a maximum of five classes of antibiotics, one or more PMQR genes and/or a class 1 integron gene cassette. This study shows that ubiquitous bacteria, other than those monitored in water quality controls, are important vectors of antibiotic resistance and can be disseminated from hospital effluent to aquatic environments. This information is relevant to support management options aiming at the control of this public health problem.

Epilithonimonas ginsengisoli sp. nov., isolated from soil of a ginseng field.

A novel Gram-staining-negative, rod-shaped bacterium, designated DCY78(T), was isolated from soil of a ginseng field in Yeon-cheon province (38° 04' 00″ N 126° 57' 00″ E), Republic of Korea. The phylogenetic analysis based on 16S rRNA gene sequences showed that strain DCY78(T) belonged to the genus Epilithonimonas and was most closely related to Epilithonimonas lactis DSM 19921(T) (98.5 % sequence similarity) and Epilithonimonas tenax DSM 16811(T) (97.8 %). Growth occurred at 10-30 °C with an optimum temperature of 28 °C. The pH range for growth was pH 5.5-8.0. The major polar lipids were found to be phosphatidylethanolamine three unidentified amino lipids and one unidentified polar lipid. The only predominant quinone was MK-6. The major polyamines were sym-homospermidine and spermidine. The major fatty acids were summed feature 3 (comprising C16 : 1ω6c and/or C16 : 1ω7c), iso-C15 : 0 and iso-C17 : 0 3-OH. The DNA G+C content was 37.9 mol%. On the basis of the phenotypic and genotypic analysis, the isolate is classified as representative of a novel species in the genus Epilithonimonas, for which the name Epilithonimonas ginsengisoli is proposed. The type strain is DCY78(T) ( = KCTC 32174(T) = JCM 19896(T)).

Polycyclic aromatic hydrocarbon degradation of phytoplankton-associated Arenibacter spp. and description of Arenibacter algicola sp. nov., an aromatic hydrocarbon-degrading bacterium.

Pyrosequencing of the bacterial community associated with a cosmopolitan marine diatom during enrichment with crude oil revealed several Arenibacter phylotypes, of which one (OTU-202) had become significantly enriched by the oil. Since members of the genus Arenibacter have not been previously shown to degrade hydrocarbons, we attempted to isolate a representative strain of this genus in order to directly investigate its hydrocarbon-degrading potential. Based on 16S rRNA sequencing, one isolate (designated strain TG409(T)) exhibited >99% sequence identity to three type strains of this genus. On the basis of phenotypic and genotypic characteristics, strain TG409(T) represents a novel species in the genus Arenibacter, for which the name Arenibacter algicola sp. nov. is proposed. We reveal for the first time that polycyclic aromatic hydrocarbon (PAH) degradation is a shared phenotype among members of this genus, indicating that it could be used as a taxonomic marker for this genus. Kinetic data for PAH mineralization rates showed that naphthalene was preferred to phenanthrene, and its mineralization was significantly enhanced in the presence of glass wool (a surrogate for diatom cell surfaces). During enrichment on hydrocarbons, strain TG409(T) emulsified n-tetradecane and crude oil, and cells were found to be preferentially attached to oil droplets, indicating an ability by the strain to express cell surface amphiphilic substances (biosurfactants or bioemulsifiers) as a possible strategy to increase the bioavailability of hydrocarbons. This work adds to our growing knowledge on the diversity of bacterial genera in the ocean contributing to the degradation of oil contaminants and of hydrocarbon-degrading bacteria found living in association with marine eukaryotic phytoplankton.

Zeaxanthin production by novel marine isolates from coastal sand of India and its antioxidant properties.

Zeaxanthin carotenoids are class of commercially important natural products and diverse biomolecules produced by plants and many microorganisms. Bacteria often produce a cocktail of polar and nonpolar carotenoids limiting their industrial applications. Marine members of the family Flavobacteriaceae are known to produce potential carotenoids such as astaxanthin and zeaxanthin. A few bacterial species have been reported for the predominant production zeaxanthin. Here, we report the molecular identification of the zeaxanthin as a major carotenoid produced by two novel bacteria (YUAB-SO-11 and YUAB-SO-45) isolated from sandy beaches of South West Coast of India and the effect of carbon sources on the production of zeaxanthin. The strains were identified based on the 16S rRNA gene sequencing as a member of genus Muricauda. The closest relatives of YUAB-SO-11 and YUAB-SO-45 were Muricauda aquimarina (JCM 11811(T)) (98.9 %) and Muricauda olearia (JCM 15563(T)) (99.2 %), respectively, indicating that both of these strains might represent a novel species. The highest level of zeaxanthin production was achieved (YUAB-SO-11, 1.20 ± 0.11 mg g(-1)) and (YUAB-SO-45, 1.02 ± 0.13 mg g(-1)) when cultivated in marine broth supplemented with 2 % NaCl (pH 7) and incubated at 30 °C. Addition of 0.1 M glutamic acid, an intermediate of citric acid cycle, enhanced the zeaxanthin production as 18 and 14 % by the strains YUAB-SO-11 and YUAB-SO-45 respectively. The zeaxanthin showed in vitro nitric oxide scavenging, inhibition of lipid peroxidation, and 2,2-diphenyl-1-picryl hydrazyl scavenging activities higher than the commercial zeaxanthin. The results of this study suggest that two novel strains YUAB-SO-11 and YUAB-SO-45 belonging to genus Muricauda produce zeaxanthin as a predominant carotenoid, and higher production of zeaxanthin was achieved on glutamic acid supplementation. The pigment showed good in vitro antioxidant activity, which can be exploited further for commercial applications.

Genome shrinkage and loss of nutrient-providing potential in the obligate symbiont of the primitive termite Mastotermes darwiniensis.

Beneficial microbial associations with insects are common and are classified as either one or a few intracellular species that are vertically transmitted and reside intracellularly within specialized organs or as microbial assemblages in the gut. Cockroaches and termites maintain at least one if not both beneficial associations. Blattabacterium is a flavobacterial endosymbiont of nearly all cockroaches and the termite Mastotermes darwiniensis and can use nitrogenous wastes in essential amino acid and vitamin biosynthesis. Key changes during the evolutionary divergence of termites from cockroaches are loss of Blattabacterium, diet shift to wood, acquisition of a specialized hindgut microbiota, and establishment of advanced social behavior. Termite gut microbes collaborate to fix nitrogen, degrade lignocellulose, and produce nutrients, and the absence of Blattabacterium in nearly all termites suggests that its nutrient-provisioning role has been replaced by gut microbes. M. darwiniensis is a basal, extant termite that solely retains Blattabacterium, which would show evidence of relaxed selection if it is being supplanted by the gut microbiome. This termite-associated Blattabacterium genome is ∼8% smaller than cockroach-associated Blattabacterium genomes and lacks genes underlying vitamin and essential amino acid biosynthesis. Furthermore, the M. darwiniensis gut microbiome membership is more consistent between individuals and includes specialized termite gut-associated bacteria, unlike the more variable membership of cockroach gut microbiomes. The M. darwiniensis Blattabacterium genome may reflect relaxed selection for some of its encoded functions, and the loss of this endosymbiont in all remaining termite genera may result from its replacement by a functionally complementary gut microbiota.

Convergent evolution of metabolic roles in bacterial co-symbionts of insects.

A strictly host-dependent lifestyle has profound evolutionary consequences for bacterial genomes. Most prominent is a sometimes-dramatic amount of gene loss and genome reduction. Recently, highly reduced genomes from the co-resident intracellular symbionts of sharpshooters were shown to exhibit a striking level of metabolic interdependence. One symbiont, called Sulcia muelleri (Bacteroidetes), can produce eight of the 10 essential amino acids, despite having a genome of only 245 kb. The other, Baumannia cicadellinicola (gamma-Proteobacteria), can produce the remaining two essential amino acids as well as many vitamins. Cicadas also contain the symbiont Sulcia, but lack Baumannia and instead contain the co-resident symbiont Hodgkinia cicadicola (alpha-Proteobacteria). Here we report that, despite at least 200 million years of divergence, the two Sulcia genomes have nearly identical gene content and gene order. Additionally, we show that despite being phylogenetically distant and drastically different in genome size and architecture, Hodgkinia and Baumannia have converged on gene sets conferring similar capabilities for essential amino acid biosynthesis, in both cases precisely complementary to the pathways conserved in Sulcia. In contrast, they have completely divergent capabilities for vitamin biosynthesis. Despite having the smallest gene set known in bacteria, Hodgkinia devotes at least 7% of its proteome to cobalamin (vitamin B(12)) biosynthesis, a significant metabolic burden. The presence of these genes can be explained by Hodgkinia's retention of the cobalamin-dependent version of methionine synthase instead of the cobalamin-independent version found in Baumannia, a situation that necessitates retention of cobalamin biosynthetic capabilities to make the essential amino acid methionine.

Muricauda olearia sp. nov., isolated from crude-oil-contaminated seawater, and emended description of the genus Muricauda.

A Gram-staining-negative, rod-shaped and non-motile bacterium, designated CL-SS4T, was isolated from crude-oil-contaminated seawater from the west coast of Korea and was investigated by means of a polyphasic taxonomic approach. Strain CL-SS4T grew optimally at 25-30 degrees C, at pH 6.8-7.7 and in the presence of 2-3% sea salts. The major fatty acids were iso-C17:0 3-OH, iso-C15:0 and iso-C15:1 G. The major isoprenoid quinone was MK-6. The DNA G+C content was 50.7 mol%. Analysis of the 16S rRNA gene sequence of strain CL-SS4T revealed that it was a member of the genus Muricauda, sharing 95.7-96.9% sequence similarity with the type strains of Muricauda species and being most closely related to Muricauda aquimarina SW-63T. Phylogenetic analyses based on 16S rRNA gene sequences confirmed that strain CL-SS4T formed a deep lineage related to the genus Muricauda. Strain CL-SS4T was distinguishable from recognized Muricauda species on the basis of differential phenotypic characteristics and DNA G+C content. Based on these results, it is proposed that strain CL-SS4T represents a novel species of the genus Muricauda, for which the name Muricauda olearia sp. nov. is proposed. An emended description of the genus Muricauda is also proposed. The type strain is CL-SS4T (=KCCM 90075T=JCM 15563T).

Extremophile extracts and enhancement techniques show promise for the development of a live vaccine against Flavobacterium columnare.

The effects of temperature, ionic strength, and new cryopreservatives derived from polar ice bacteria were investigated to help accelerate the development of economical, live attenuated vaccines for aquaculture. Extracts of the extremophile Gelidibacter algens functioned very well as part of a lyophilization cryoprotectant formulation in a 15-week storage trial. The bacterial extract and trehalose additives resulted in significantly higher colony counts of columnaris bacteria (Flavobacterium columnare) compared to nonfat milk or physiological saline at all time points measured. The bacterial extract combined with trehalose appeared to enhance the relative efficiency of recovery and growth potential of columnaris in flask culture compared to saline, nonfat milk, or trehalose-only controls. Pre-lyophilization temperature treatments significantly affected F. columnare survival following rehydration. A 30-min exposure at 0 degrees C resulted in a 10-fold increase in bacterial survival following rehydration compared to mid-range temperature treatments. The brief 30 and 35 degrees C pre-lyophilization exposures appeared to be detrimental to the rehydration survival of the bacteria. The survival of F. columnare through the lyophilization process was also strongly affected by changes in ionic strength of the bacterial suspension. Changes in rehydration constituents were also found to be important in promoting increased survival and growth. As the sodium chloride concentration increased, the viability of rehydrated F. columnare decreased.

Yeosuana aromativorans gen. nov., sp. nov., a mesophilic marine bacterium belonging to the family Flavobacteriaceae, isolated from estuarine sediment of the South Sea, Korea.

A marine bacterium, GW1-1T, capable of degrading benzo[a]pyrene (BaP), was isolated from estuarine sediments of the South Sea (the Korea Strait), Korea, after an enrichment culture maintained for 2 years in a medium supplemented with a mixture of BaP and pyrene. The strain formed yellowish-brown colonies on marine agar 2216. Cells were strictly aerobic, non-motile, Gram-negative rods and produced non-diffusible carotenoid pigments. Optimal growth occurred in the presence of 1 % (w/v) NaCl and at pH 7 and 33-36 degrees C. No growth occurred without supplementation with either CaCl2 or MgCl2, even in the presence of NaCl. Phylogenetic analysis based on the nearly complete sequence of the 16S rRNA gene revealed that the isolate formed a phyletic lineage with the genera Gelidibacter (93.9-94.7 % gene sequence similarity), Subsaximicrobium (93.3 %) and Subsaxibacter (93.9 %). The isolate also showed high sequence similarities to Gaetbulibacter saemankumensis (94.5 %), Algibacter lectus (94.2 %), members of the genus Bizionia (93.6-94.3 %) and Formosa algae (93.2 %), even though it belonged to a different phyletic line. The major respiratory quinones of the isolate were menaquinones MK-5 and MK-6. The DNA G+C content was 51.4 mol%. Dominant fatty acids were i-15 : 0, a-15 : 0, i-15 : 1omega10c and 16 : 1. On the basis of this polyphasic taxonomic evidence, strain GW1-1T is classified as a member of a novel genus and species in the family Flavobacteriaceae, for which the name Yeosuana aromativorans gen. nov., sp. nov. is proposed. The type strain of the type species is GW1-1T (=KCCM 42019T = JCM 12862T).