Consistency and Variation in the Kelp Microbiota: Patterns of Bacterial Community Structure Across Spatial Scales.

Kelp species are distributed along ~ 25% of the world's coastlines and the forests they form represent some of the world's most productive and diverse ecosystems. Like other marine habitat-formers, the associated microbial community is fundamental for host and, in turn, wider ecosystem functioning. Given there are thousands of bacteria-host associations, determining which relationships are important remains a major challenge. We characterised the associated bacteria of two habitat-forming kelp species, Laminaria hyperborea and Saccharina latissima, from eight sites across a range of spatial scales (10 s of metres to 100 s of km) in the northeast Atlantic. We found no difference in diversity or community structure between the two kelps, but there was evidence of regional structuring (across 100 s km) and considerable variation between individuals (10 s of metres). Within sites, individuals shared few amplicon sequence variants (ASVs) and supported a very small proportion of diversity found across the wider study area. However, consistent characteristics between individuals were observed with individual host communities containing a small conserved "core" (8-11 ASVs comprising 25 and 32% of sample abundances for L. hyperborea and S. latissima, respectively). At a coarser taxonomic resolution, communities were dominated by four classes (Planctomycetes, Gammaproteobacteria, Alphaproteobacteria and Bacteroidia) that made up ~ 84% of sample abundances. Remaining taxa (47 classes) made up very little contribution to overall abundance but the majority of taxonomic diversity. Overall, our study demonstrates the consistent features of kelp bacterial communities across large spatial scales and environmental gradients and provides an ecologically meaningful baseline to track environmental change.

Ornithinimicrobium laminariae sp. nov., isolated from the kelp Laminaria japonica.

A Gram-stain-positive, aerobic, non-sporulating, yellow-pigmented and rod or cocci-shaped bacterium, designated Arc0846-15T, was isolated from the kelp Laminaria japonica. Strain Arc0846-15T was found to grow at 16-35 °C (optimum, 28 °C), at pH 6.0-9.5 (optimum, 7.0) and in the presence of 0-6 % (w/v) NaCl (optimum, 2 %). Cells were positive for catalase and negative for oxidase activity. Phylogenetic analyses, based on 16S rRNA gene sequence comparisons, revealed that the nearest phylogenetic neighbour strains of strain Arc0846-15T were Ornithinimicrobium murale 01 Gi-040T (96.2 %), Ornithinimicrobium kibberense K22-20T (96.1 %) and Ornithinimicrobium humiphilum HKI 0124T (95.2 %). Based on phylogenomic analysis, the average nucleotide identity values between strain Arc0846-15T and the neighbour strains were 69.8, 69.7 and 69.8 %, respectively; the digital DNA-DNA hybridization values between strain Arc0846-15T and its three closest neighbour strains were 18.8, 19.1 and 19.3 %, respectively. The predominant menaquinone was MK-8 (H4). The dominant cellular fatty acids were C17 : 1 ω8c, iso-C15 : 0, iso-C16 : 0 and C17 : 0. The polar lipids contained diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol, glycolipid, one unidentified aminolipid and four unidentified lipids. The DNA G+C content of strain Arc0846-15T was 61.6 mol% based on the whole genome sequence. Based on the phylogenetic and phenotypic characteristics, strain Arc0846-15T is considered to represent a novel species of the genus Ornithinimicrobium, for which the name Ornithinimicrobium laminariae sp. nov. is proposed, with Arc0846-15T (=KCTC 49655T=MCCC 1K06093T) as the type strain.

Physical Stress Induced Reduction of Proliferating Cells and Differentiated Neuroblasts Is Ameliorated by Fermented Laminaria japonica Extract Treatment.

Laminaria japonica is widely cultivated in East Asia, including South Korea. Fucoidan, a main component of L. japonica, protects neurons from neurological disorders such as ischemia and traumatic brain injury. In the present study, we examined the effects of extract from fermented L. japonica on the reduction of proliferating cells and neuroblasts in mice that were physically (with electric food shock) or psychologically (with visual, auditory and olfactory sensation) stressed with the help of a communication box. Vehicle (distilled water) or fermented L. japonica extract (50 mg/kg) were orally administered to the mice once a day for 21 days. On the 19th day of the treatment, physical and psychological stress was induced by foot shock using a communication box and thereafter for three days. Plasma corticosterone levels were significantly increased after exposure to physical stress and decreased Ki67 positive proliferating cells and doublecortin immunoreactive neuroblasts. In addition, western blot analysis demonstrated that physical stress as well as psychological stress decreased the expression levels of brain-derived neurotrophic factor (BDNF) and the number of phosphorylated cAMP response element binding protein (pCREB) positive nuclei in the dentate gyrus. Fermentation of L. japonica extract significantly increased the contents of reduced sugar and phenolic compounds. Supplementation with fermented L. japonica extract significantly ameliorated the increases of plasma corticosterone revels and decline in the proliferating cells, neuroblasts, and expression of BDNF and pCREB in the physically stressed mice. These results indicate that fermented L. japonica extract has positive effects in ameliorating the physical stress induced reduction in neurogenesis by modulating BDNF and pCREB expression in the dentate gyrus.

Diversity of bacteria populations associated with different thallus regions of the brown alga Laminaria digitata.

Stipitate kelp species such as Laminaria digitata dominate most cold-water subtidal rocky shores and form underwater forests which are among the most productive coastal systems worldwide. Laminaria also sustains rich bacterial communities which offer a variety of biotechnological applications. However, to date, in-depth studies on the diversity and uniqueness of bacterial communities associated with this macroalgal species, their ecological role and their interactions with the alga are under-represented. To address this, the epibacterial populations associated with different thallus regions (holdfast, stipe, meristem, blade) of this brown seaweed were investigated using high-throughput Illumina sequencing of the 16S rRNA genes. The results show that epibacterial communities of the brown seaweed are significantly different and specific to the thallus region, with the shared bacterial population comprising of only 1.1% of the total amplicon sequence variants. The diverse holdfast and blade tissues formed distinct clusters while the meristem and stipe regions are more closely related. The data obtained further supports the hypothesis that macroalgal bacterial communities are shaped by morphological niches and display specificity.

Structural and molecular basis for the substrate positioning mechanism of a new PL7 subfamily alginate lyase from the arctic.

Alginate lyases play important roles in alginate degradation in the ocean. Although a large number of alginate lyases have been characterized, little is yet known about those in extremely cold polar environments, which may have unique mechanisms for environmental adaptation and for alginate degradation. Here, we report the characterization of a novel PL7 alginate lyase AlyC3 from Psychromonas sp. C-3 isolated from the Arctic brown alga Laminaria, including its phylogenetic classification, catalytic properties, and structure. We propose the establishment of a new PM-specific subfamily of PL7 (subfamily 6) represented by AlyC3 based on phylogenetic analysis and enzymatic properties. Structural and biochemical analyses showed that AlyC3 is a dimer, representing the first dimeric endo-alginate lyase structure. AlyC3 is activated by NaCl and adopts a novel salt-activated mechanism; that is, salinity adjusts the enzymatic activity by affecting its aggregation states. We further solved the structure of an inactive mutant H127A/Y244A in complex with a dimannuronate molecule and proposed the catalytic process of AlyC3 based on structural and biochemical analyses. We show that Arg82 and Tyr190 at the two ends of the catalytic canyon help the positioning of the repeated units of the substrate and that His127, Tyr244, Arg78, and Gln125 mediate the catalytic reaction. Our study uncovers, for the first time, the amino acid residues for alginate positioning in an alginate lyase and demonstrates that such residues involved in alginate positioning are conserved in other alginate lyases. This study provides a better understanding of the mechanisms of alginate degradation by alginate lyases.

Laminariales Host Does Impact Lipid Temperature Trajectories of the Fungal Endophyte Paradendryphiella salina (Sutherland.).

Kelps are colonized by a wide range of microbial symbionts. Among them, endophytic fungi remain poorly studied, but recent studies evidenced yet their high diversity and their central role in algal defense against various pathogens. Thus, studying the metabolic expressions of kelp endophytes under different conditions is important to have a better understanding of their impacts on host performance. In this context, fatty acid composition is essential to a given algae fitness and of interest to food web studies either to measure its nutritional quality or to infer about its contribution to consumers diets. In the present study, Paradendryphiella salina, a fungal endophyte was isolated from Saccharina latissima (L.) and Laminaria digitata (Hudson.) and its fatty acid composition was assessed at increasing salinity and temperature conditions. Results showed that fungal composition in terms of fatty acids displayed algal-dependent trajectories in response to temperature increase. This highlights that C18 unsaturated fatty acids are key components in the host-dependant acclimation of P. salina to salinity and temperature changes.

Salinibaculum litoreum gen. nov., sp. nov., isolated from salted brown alga Laminaria.

A novel Gram-stain-negative, aerobic and rod-shaped halophilic archaeon, designated HD8-45T, was isolated from the red brine of salted brown alga Laminaria produced at Dalian, PR China. According to the results of 16S rRNA gene and rpoB' gene sequence comparisons, strain HD8-45T showed the highest sequence similarity to the corresponding genes of Salinirussus salinus YGH44T (95.1 and 85.2 % similarities, respectively), Halovenus aranensis EB27T (91.2 and 86.0 % similarities, respectively). The low sequence similarity and the phylogeny implied the novel generic status of strain HD8-45T. Genomic relatedness analyses showed that strain HD8-45T were clearly distinguished from other species in the order Halobacteriales, with average nucleotide identity, amino acid identity and in silico DNA-DNA hybridization values not more than 75.1, 65.6 and 21.5 %. The polar lipid pattern contained phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester, two major glycolipids and two minor glycolipids. The two major glycolipids and a minor glycolipid were chromatographically identical to disulfated mannosyl glucosyl diether, sulfated mannosyl glucosyl diether and mannosyl glucosyl diether, respectively. The major respiratory quinones were menaquinone MK-8 and MK-8(H2). The DNA G+C content was 62.0 mol% (Tm) and 61.9 mol% (genome). All these results showed that strain HD8-45T represents a novel species of a new genus in the order Halobacteriales, for which the name Salinibaculum litoreum gen. nov., sp. nov. is proposed. The type strain of Salinibaculum litoreum is HD8-45T (=CGMCC 1.15328T=JCM 31107T).

Halostella pelagica sp. nov. and Halostella litorea sp. nov., isolated from salted brown alga Laminaria.

Three rod-shaped halophilic archaeal strains, DL-M4T, LYG-109 and DLLS-108T, were isolated from the salted brown alga Laminaria produced in different marine areas of PR China. Cells of strains were motile, formed red-pigmented colonies on agar and lysed in distilled water. The three strains grew optimally with 2.6 M NaCl, with 0.05-0.3 M MgCl2, at 37 °C and at pH 7.0-7.5. The results of phylogenetic analyses based on the 16S rRNA and rpoB' genes differentiated these strains into two clusters belonging to the genus Halostella, which currently contains Halostella salina CBA1114T and Halostella limicola LT12T. Strains DL-M4T and LYG-109 formed a single cluster separate from the current two members of Halostella (94.4-95.7 and 90.0-90.9 % similarities, respectively) while strain DLLS-108T had Hsl. salina CBA1114T as its nearest neighbour (97.7-97.8 and 95.9 % similarities, respectively) and was separated from Hsl. limicola LT12T (94.4-95.8 and 93.4 % similarities, respectively). These clusters represented two distinct novel species as indicated by phenotypic characteristics, polar lipid compositions and whole-genome comparisons. Diverse phenotypic characteristics, morphology and growth characteristics, nutrition and miscellaneous biochemical tests differentiate strains DL-M4T, LYG-109, DLLS-108T from Hsl. limicola LT12T and Hsl. salina CBA1114T. Strains DL-M4T and LYG-109 contained phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester and three unidentified glycolipids, while strain DLLS-108T contained these polar lipids and two unidentified phospholipids. The major respiratory quinones detected in the three isolates were menaquinone MK-8 and MK-8(H2). The average nucleotide identity (ANI) and in silico DNA-DNA hybridization (isDDH) values between the isolated strains and the current two members of Halostella were found to be 79.3-86.6 (ANI) and 22.9-49.8 % (isDDH). All these results showed that the three isolates represent two novel species of the genus Halostella for which the names Halostella pelagica sp. nov. [type strain dl-M4T (=CGMCC 1.13603T=JCM 32954T)] and Halostella litorea sp. nov. [type strain DLLS-108T(=CGMCC 1.13610T=JCM 32955T)] are proposed.

Effects of a polysaccharide-rich extract derived from Irish-sourced Laminaria digitata on the composition and metabolic activity of the human gut microbiota using an in vitro colonic model.

BACKGROUND: Brown seaweeds are known to be a rich source of fiber with the presence of several non-digestible polysaccharides including laminarin, fucoidan and alginate. These individual polysaccharides have previously been shown to favorably alter the gut microbiota composition and activity albeit the effect of the collective brown seaweed fiber component on the microbiota remains to be determined. METHODS: This study investigated the effect of a crude polysaccharide-rich extract obtained from Laminaria digitata (CE) and a depolymerized CE extract (DE) on the gut microbiota composition and metabolism using an in vitro fecal batch culture model though metagenomic compositional analysis using 16S rRNA FLX amplicon pyrosequencing and short-chain fatty acid (SCFA) analysis using GC-FID. RESULTS: Selective culture analysis showed no significant changes in cultured lactobacilli or bifidobacteria between the CE or DE and the cellulose-negative control at any time point measured (0, 5, 10, 24, 36, 48 h). Following metagenomic analysis, the CE and DE significantly altered the relative abundance of several families including Lachnospiraceae and genera including Streptococcus, Ruminococcus and Parabacteroides of human fecal bacterial populations in comparison to cellulose after 24 h. The concentrations of acetic acid, propionic acid, butyric acid and total SCFA were significantly higher for both the CE and DE compared to cellulose after 10, 24, 36 and 48 h fermentation (p < 0.05). Furthermore, the acetate:propionate ratio was significantly reduced (p < 0.05) for both CD and DE following 24, 36 and 48 h fermentation. CONCLUSION: The microbiota-associated metabolic and compositional changes noted provide initial indication of putative beneficial health benefits of L. digitata in vitro; however, research is needed to clarify if L. digitata-derived fiber can favorably alter the gut microbiota and confer health benefits in vivo.

Algicoccus marinus gen. nov. sp. nov., a marine bacterium isolated from the surface of brown seaweed Laminaria japonica.

A Gram-staining-negative, strictly aerobic, non-motile, ovoid- to rod-shaped bacterium, designated as HZ20T, was isolated from the surface of a brown seaweed (Laminaria japonica) sample collected from the East China Sea. Colonies are 1.0-2.0 mm in diameter, smooth, circular, convex and yellow after grown on MA at 28 °C for 72 h. The strain was found to grow at 4-50 °C (optimum, 37 °C), pH 5.0-9.5 (optimum, pH 7.0-7.5) and with 0-10% (w/v) NaCl (optimum, 1.0-1.5%). Chemotaxonomic analysis showed ubiquinone-8 as the only quinone, C17:0 cyclo, C16:0, summed feature 8 (C18:1ω7c and/or C18:1ω6c) and summed feature 2 (C12:0 aldehyde/unknown 10.9525/C16:1 iso I/C14:0 3OH) as the major fatty acids (> 5%), and diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, one unidentified amino phospholipid, two unidentified phospholipids, five unidentified glycolipid and two unidentified lipids as the polar lipids. The DNA G + C content was 55.5 mol %. 16S rRNA gene sequences of the isolate showed highest similarities to Bordetella flabilis AU10664T (97.1%), Parapusillimonas granuli Ch07T (97.1%), Paracandidimonas soli IMT-305T (97.1%), Kerstersia gyiorum LMG5906T (97.0%) and Bordetella sputigena LMG 28641T (97.0%). The phylogenetic trees using 16S rRNA gene and genome sequences both showed that the strain HZ20T formed a deep branch separated from other related genera, indicating that it represents a novel species of a novel genus. The calculated average nucleotide identity (ANI) and percent of conserved proteins (POCP) values using genome sequences of strain HZ20T and related strains also support this conclusion. Based on the phenotypic properties and phylogenetic distinctiveness, we propose strain HZ20T (= MCCC 1K03465T = KCTC 62330T) to represent a novel species of a novel genus with the name Algicoccus marinus gen. nov. sp. nov.

Halorussus litoreus sp. nov., isolated from the salted brown alga Laminaria.

A halophilic archaeal strain, designated HD8-51T, was isolated from the salted brown alga Laminaria. Cells of strain HD8-51T were motile, pleomorphic coccoid or ovoid, and formed red-pigmented colonies on agar plates. Strain HD8-51T grew optimally at 3.1 M NaCl, 0.03 M MgCl2, 30 °C and pH 7.0. Cells lysed in distilled water and the minimal NaCl concentration to prevent cell lysis was 0.85 M. Based on phylogenetic analyses of the 16S rRNA and rpoB' genes, strain HD8-51T was most closely related to members of the genus Halorussus (92.3-95.6 % and 89.2-91.7% similarities, respectively). The average nucleotide identity values and in silico DNA-DNA hybridization values between strain HD8-51T and Halorussus rarus TBN4T were 81.69 and 24.5 %, respectively. The major polar lipids of strain HD8-51T were phosphatidic acid (PA), phosphatidylglycerol (PG), phosphatidylglycerol phosphate methyl ester (PGP-Me), phosphatidylglycerol sulfate (PGS) and five glycolipids, sulfated galactosyl mannosyl glucosyl diether (S-TGD-1), galactosyl mannosyl glucosyl diether (TGD-1), sulfated mannosyl glucosyl diether (S-DGD-1), mannosyl glucosyl diether (DGD-1) and diglycosyl diether (DGD-2). The DNA G+C content was 65.9 mol%. Based on phenotypic, chemotaxonomic and phylogenetic properties, strain HD8-51T represents a novel species of the genus Halorussus, for which the name Halorussus litoreus sp. nov. is proposed. The type strain is HD8-51T (=CGMCC 1.15333T=JCM 31109T).

Cytotoxic Tricycloalternarene Compounds from Endophyte Alternaria sp. W-1 Associated with Laminaria japonica.

The chemical investigation of the culture filtrate of endophyte Alternaria sp. W-1 associated with Laminaria japonica provided a new tricycloalternarene compound, 2H-(2E)-tricycloalternarene 12a (1), together with five known analogs: (2E)-tricycloalternarene 12a (2), tricycloalternarene 3a (3), tricycloalternarene F (4), 15-hydroxyl tricycloalternarene 5b (5), and ACTG-Toxin D (6). In vitro cytotoxicity against the human hepatocellular carcinoma cell line SMMC-7721 and the human gastric carcinoma cell line SGC-7901 was evaluated by the MTT method. Compounds 1, 3, and 4 inhibited the growth of SMMC-7721 cells with IC50 values of 49.7 ± 1.1, 45.8 ± 4.6, and 80.3 ± 3.8 µg/mL, respectively, while the IC50 value of the positive control cisplatin was 6.5 ± 0.5 µg/mL. Compounds 3 and 6 also showed moderate anti-proliferation activity against SGC-7901 cells with IC50 values of 53.2 ± 2.9 and 35.1 ± 0.8 µg/mL, respectively, while the IC50 value of cisplatin was 4.5 ± 0.6 µg/mL. Further studies revealed that the in vitro anticancer activity of compound 3 to SMMC-7721 cells was related to G1 phase cell cycle arrest and cell apoptosis, and the induced apoptosis was involved in both the mitochondrial pathway and the death receptor pathway. This is the first report on the anticancer mechanism of tricycloalternarene compounds.

Isolation and Complete Genome Sequence of Algibacter alginolytica sp. nov., a Novel Seaweed-Degrading Bacteroidetes Bacterium with Diverse Putative Polysaccharide Utilization Loci.

The members of the phylum Bacteroidetes are recognized as some of the most important specialists for the degradation of polysaccharides. However, in contrast to research on Bacteroidetes in the human gut, research on polysaccharide degradation by marine Bacteroidetes is still rare. The genus Algibacter belongs to the Flavobacteriaceae family of the Bacteroidetes, and most species in this genus are isolated from or near the habitat of algae, indicating a preference for the complex polysaccharides of algae. In this work, a novel brown-seaweed-degrading strain designated HZ22 was isolated from the surface of a brown seaweed (Laminaria japonica). On the basis of its physiological, chemotaxonomic, and genotypic characteristics, it is proposed that strain HZ22 represents a novel species in the genus Algibacter with the proposed name Algibacter alginolytica sp. nov. The genome of strain HZ22, the type strain of this species, harbors 3,371 coding sequences (CDSs) and 255 carbohydrate-active enzymes (CAZymes), including 104 glycoside hydrolases (GHs) and 18 polysaccharide lyases (PLs); this appears to be the highest proportion of CAZymes (∼7.5%) among the reported strains in the class Flavobacteria Seventeen polysaccharide utilization loci (PUL) are predicted to be specific for marine polysaccharides, especially algal polysaccharides from red, green, and brown seaweeds. In particular, PUL N is predicted to be specific for alginate. Taking these findings together with the results of assays of crude alginate lyases, we prove that strain HZ22(T) can completely degrade alginate. This work reveals that strain HZ22(T) has good potential for the degradation of algal polysaccharides and that the structure and related mechanism of PUL in strain HZ22(T) are worth further research.

Maximizing the utilization of Laminaria japonica as biomass via improvement of alginate lyase activity in a two-phase fermentation system.

Brown seaweed contains up to 67% of carbohydrates by dry weight and presents high potential as a polysaccharide feedstock for biofuel production. To effectively use brown seaweed as a biomass, degradation of alginate is the major challenge due to its complicated structure and low solubility in water. This study focuses on the isolation of alginate degrading bacteria, determining of the optimum fermentation conditions, as well as comparing the conventional single fermentation system with the two-phase fermentation system which is separately using alginate and mannitol extracted from Laminaria japonica. Maximum yield of organic acids production and volatile solids reduction obtained were 0.516 g/g and 79.7%, respectively, using the two-phase fermentation system in which alginate fermentation was carried out at pH 7 and mannitol fermentation at pH 8. The two-phase fermentation system increased the yield of organic acids production by 1.14 times and led to a 1.45-times reduction of VS when compared to the conventional single fermentation system at pH 8. The results show that the two-phase fermentation system improved the utilization of alginate by separating alginate from mannitol leading to enhanced alginate lyase activity.

Halovenus rubra sp. nov., isolated from salted brown alga Laminaria.

Halophilic archaeal strain R28(T) was isolated from the brown alga Laminaria produced at Dalian, Liaoning Province, China. The cells of the strain were pleomorphic and lysed in distilled water, stained Gram-negative, and formed red-pigmented colonies. Strain R28(T) was able to grow at 25-50 °C (optimum 42 °C), in the presence of 3.1-5.1 M NaCl (optimum 3.9 M NaCl), with 0.005-1.0 M MgCl(2) (optimum 0.01 M MgCl(2)) and at pH 6.0-9.5 (optimum pH 7.0-7.5). The minimal NaCl concentration to prevent cell lysis was 15 % (w/v). The major polar lipids of the strain were identified as phosphatidic acid, phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester, and two glycolipids chromatographically identical to those of Halovenus aranensis CGMCC 1.11001(T). The 16S rRNA gene and rpoB' gene of strain R28(T) were phylogenetically related to the corresponding genes of Hvn. aranensis CGMCC 1.11001(T) (91.9-97.2 and 82.9 % nucleotide identity, respectively). The DNA G+C content of strain R28(T) was determined to be 56.3 mol%. The phenotypic, chemotaxonomic, and phylogenetic properties suggest that strain R28(T) (=CGMCC 1.10592(T) = JCM 17269(T)) represents a novel species of the genus Halovenus, for which the name Halovenus rubra sp. nov. is proposed.

Halopenitus salinus sp. nov., isolated from the brine of salted brown alga Laminaria.

A halophilic archaeal strain, SKJ47(T), was isolated from a commercial preparation of the brown alga Laminaria produced at Dalian, Liaoning Province, China. Cells of the strain were observed to be short rods, stain Gram-negative, and to form red-pigmented colonies on solid media. Strain SKJ47(T) was found to be able to grow at 20-50 °C (optimum 37 °C), at 0.9-4.8 M NaCl (optimum 2.6-3.1 M), at pH 6.0-9.5 (optimum pH 7.0). The cells lysed in distilled water and the minimal NaCl concentration to prevent cell-lysis was found to be 5% (w/v). The major polar lipids of the strain were identified as phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester, phosphatidylglycerol sulfate and two glycolipids chromatographically identical to those of Halopenitus persicus IBRC 10041(T). The 16S rRNA gene and rpoB' gene of strain SKJ47(T) were found to be phylogenetically related to the corresponding genes of Halopenitus malekzadehii IBRC-M 10418(T) (96.3 and 91.9% nucleotide identity, respectively) and Hpt. persicus IBRC 10041(T) (96.2 and 93.8%). The DNA G+C content of strain SKJ47(T) was determined to be 65.0 mol%. The phenotypic, chemotaxonomic and phylogenetic properties suggested that strain SKJ47(T) (=CGMCC 1.12229(T) = JCM 18641(T)) represents a new species of the genus Halopenitus, for which the name Halopenitus salinus sp. nov. is proposed.

Draft genome sequence of Microbulbifer elongatus strain HZ11, a brown seaweed-degrading bacterium with potential ability to produce bioethanol from alginate.

Microbulbifer elongatus strain HZ11, was a new strain of M. elongates DSM 6810(T), which has the ability to degrade brown seaweeds such as Laminaria japonica into single cell detritus particles. Here we report a high quality draft genome of M. elongatus strain HZ11, which comprises 4,223,108bp in 9 contigs with the G+C content of 56.70%. A total of 3293 protein-coding sequences were predicted, including nine alginate lyases (EC 4.2.2.3), five agarases (EC 3.2.1.81), 2-dehydro-3-deoxygluconate kinase (EC 2.7.1.45) and all enzymes involved in the Entner-Doudoroff pathway. Our results suggest that strain HZ11 has the potential ability to produce bioethanol from alginate with moderate genetic modification, which may significantly increase the yield of bioethanol from brown seaweed and the utilization rate of brown seaweeds.

Halosimplex pelagicum sp. nov. and Halosimplex rubrum sp. nov., isolated from salted brown alga Laminaria, and emended description of the genus Halosimplex.

Two halophilic archaeal strains, R2(T) and R27(T), were isolated from the brown alga Laminaria produced at Dalian, Liaoning Province, China. Both had pleomorphic cells that lysed in distilled water, stained Gram-negative and formed red-pigmented colonies. They grew optimally at 42 °C, pH 7.0 and in the presence of 3.1-3.4 M NaCl and 0.03-0.5 M Mg(2+). The major polar lipids of the two strains were phosphatidylglycerol (PG), phosphatidylglycerol phosphate methyl ester (PGP-Me) and four major glycolipids chromatographically identical to those of Halosimplex carlsbadense JCM 11222(T). 16S rRNA gene analysis revealed that each strain had two dissimilar 16S rRNA genes and both strains were phylogenetically related to Halosimplex carlsbadense JCM 11222(T) (92.7-98.8 % similarities). The rpoB' gene similarities between strains R2(T) and R27(T) and between these strains and Halosimplex carlsbadense JCM 11222(T) were 95.7 %, 96.1 % and 95.8 %, respectively. The DNA G+C contents of strains R2(T) and R27(T) were 62.5 mol% and 64.0 mol%, respectively. The DNA-DNA hybridization values between strains R2(T) and R27(T) and between the two strains and Halosimplex carlsbadense JCM 11222(T) were 43 %, 52 % and 47 %, respectively. It was concluded that strain R2(T) ( = CGMCC 1.10586(T) = JCM 17263(T)) and strain R27(T) ( = CGMCC 1.10591(T) = JCM 17268(T)) represent two novel species of the genus Halosimplex, for which the names Halosimplex pelagicum sp. nov. and Halosimplex rubrum sp. nov. are proposed. An emended description of the genus Halosimplex is also presented.

New metabolites from the algal associated marine-derived fungus Aspergillus carneus.

The new oxepin-containing (1) and quinazolinone (2) alkaloids and new dihydrobenzofuran derivative (3) have been isolated from a marine strain of Aspergillus carneus KMM 4638. The structures of these metabolites were determined by HR-MS and 1D and 2D NMR, along with Marfey's method.

Cultivable alginate lyase-excreting bacteria associated with the Arctic brown alga Laminaria.

Although some alginate lyases have been isolated from marine bacteria, alginate lyases-excreting bacteria from the Arctic alga have not yet been investigated. Here, the diversity of the bacteria associated with the brown alga Laminaria from the Arctic Ocean was investigated for the first time. Sixty five strains belonging to nine genera were recovered from six Laminaria samples, in which Psychrobacter (33/65), Psychromonas (10/65) and Polaribacter (8/65) were the predominant groups. Moreover, 21 alginate lyase-excreting strains were further screened from these Laminaria-associated bacteria. These alginate lyase-excreting strains belong to five genera. Psychromonas (8/21), Psedoalteromonas (6/21) and Polaribacter (4/21) are the predominant genera, and Psychrobacter, Winogradskyella, Psychromonas and Polaribacter were first found to produce alginate lyases. The optimal temperatures for the growth and algiante lyase production of many strains were as low as 10–20 °C, indicating that they are psychrophilic bacteria. The alginate lyases produced by 11 strains showed the highest activity at 20–30 °C, indicating that these enzymes are cold-adapted enzymes. Some strians showed high levels of extracellular alginate lyase activity around 200 U/mL. These results suggest that these algiante lyase-excreting bacteria from the Arctic alga are good materials for studying bacterial cold-adapted alginate lyases.