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Sample records for pseudoalteromonas arctica gs230

  1. Cryoprotective properties of exopolysaccharide (P-21653) produced by the Antarctic bacterium, Pseudoalteromonas arctica KOPRI 21653.

    Science.gov (United States)

    Kim, Sung Jin; Yim, Joung Han

    2007-12-01

    Twenty-five bacterial strains that secrete mucous materials were isolated from sediment obtained from King George Island, Antarctica. Seven of these strains proved capable of producing cryoprotective exopolysaccharides. The strain KOPRI 21653 was selected for the further study of an anti-ice-nucleating polysaccharide (ANP), which originated from a polar region. KOPRI 21653 was identified as Pseudoalteromonas arctica as the result of 16S rRNA analysis. The exopolysaccharide, P-21653, was purified completely from the KOPRI 21653 cell culture via column chromatography and protease treatment. The principal sugar components of P-21653 were determined to be galactose and glucose, at a ratio of 1:1.5, via GC-MS analysis. The cryoprotective activity of P-21653 was characterized via an E. coli viability test. In the presence of 0.1% (w/v) P-21653, the survival ratio of E. coli cells was as high as 82.6% over three repeated freeze-thaw cycles. The survival ratio decreased drastically to 71.5 and 48.1%, respectively, in five and seven repeated cycle conditions; however, the survival ratios were greater over three (96.6-92.1%) to seven (100.5-91.6%) freeze-thaw cycles in the presence of 0.5 and 1.0% (w/v) P-21653. In addition, at much lower concentrations (0.1-1.0%), P-21653 resulted in survival ratios (83.1-98.4%) similar to those of two commercially available cryoprotectants (VEG plus X-1000, 92.9% and VM3, 95.3%), which were utilized at the recommended concentrations (90%). The biochemical characteristics of exopolysaccharide P-21653 reflect that this compound may be developed as a useful cryoprotectant for use in medical applications and in the food industry.

  2. Om Linguatula arctica, reinens bihulmark

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    Rolf Egil Haugerud

    1986-06-01

    Full Text Available Linguatula arctica, a newly described pentastomid species, is found in the nasal sinuses of the reindeer. It seems to cover the reindeer distribution. The prevalence in Norwegian reindeer herds is fairly high for an almost unknown parasite. L. arctica infects mostly calves. This led to the hypothesis that the reindeer mounts an immune response against the invader. The author discusses possible detrimental effects and proposes management efforts to control the parasite. Briefly, veterinary treatment is reviewed.

  3. Coccolithophores in Polar Waters: Papposphaera arctica HET and HOL revisited

    DEFF Research Database (Denmark)

    Thomsen, Helge Abildhauge; Heldal, Mikal; Østergaard, Jette B.

    2016-01-01

    It has been generally accepted based on the finding of combination coccospheres in field samples that Turrisphaera arctica and Papposphaera sarion are alternate life-cycle phases of a single species. However, while recently revisiting P. sarion it became evident that the Turrisphaera phase of thi...

  4. Bioactivity and phylogeny of the marine bacterial genus Pseudoalteromonas

    DEFF Research Database (Denmark)

    Vynne, Nikolaj Grønnegaard

    for their ability to repeatedly inhibit the fish pathogen Vibrio anguillarum 90-11-287 or Staphylococcus aureus 8325. Based on previous work, a hypothesis that antagonistic Pseudoalteromonas strains primarily were pigmented and surface associated was investigated. This Ph.D. work confirmed that surface......-associated strains were significantly more likely to possess stable antibacterial activity and be pigmented. Pseudoalteromonas strains are known as prolific producers of bioactive secondary metabolites; hence screening the global strain collection for production of novel antibiotics was initiated. Novel quinolone...... also provide information on the use of 16S rRNA gene sequences to dereplicate strain collections in biodiscovery efforts. A phylogenetic study of 16S rRNA gene sequences of the Pseudoalteromonas strains confirmed the division into two clades; one consisted of bioactive pigmented strains and one...

  5. A SEM study of the reindeer sinus worm (Linguatula arctica

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    Sven Nikander

    2009-01-01

    Full Text Available Pentastomids are a group of peculiar parasitic arthropods, often referred to as tongue worms due to the resemblance of some species to a tongue. Linguatula arctica is the sinus worm of the reindeer (Rangifer tarandus, being the only pentastomid to have a direct life cycle and an ungulate as a definite host. Here, the surface structures and internal anatomy of adult L. arctica are described as seen by scanning electron microscopy (SEM. Sinus worms were collected in the winter 1991-92 in Finnish Lapland. Paranasal cavities of about 80 reindeer were examined and 30 sinus worms were found. The sinus worms had typical Linguatula sp. morphology, being paddle-shaped, transparent, pale yellow, dorsoventrally flattened and pseudosegmented with a long tapering end. Present at the anteroventral part of the cephalothorax was an oral opening with a large, conspicuous, head-like papillar structure. Bilaterally, on both sides of this opening, was a pair of strong curved hooks. The cephalothorax and abdomen had a segmented appearance, as they showed distinct annulation. There was a small cup-shaped sensory organ present at the lateral margin on each annula. The posterior edge of each annula was roughened by tiny spines projecting backwards. Throughout the cuticular surface, small, circular depressions that represented the apical portion of chloride cells. The genital opening of the male was located medioventrally between the tips of the posterior pair of hooks, and that of the female posteroventrally and subterminally. In both sexes, the genital opening was bilaterally flanked by papillar (in males or leaf-like (in females structures. One copulating couple was present, with the male attached to the posteroventral part of the female with its anteroventral hooks and papillae. Several structures typical of arthropods and other pentastomids were identified. Because SEM allows only surfaces to be studied, the morphology and especially the sense organs of L. arctica

  6. Highly brominated antimicrobial metabolites from a marine Pseudoalteromonas sp.

    Science.gov (United States)

    Fehér, Domonkos; Barlow, Russell; McAtee, Jesse; Hemscheidt, Thomas K

    2010-11-29

    Extracts of a marine Pseudoalteromonas sp. (CMMED 290) isolated from the surface of a nudibranch collected in Kaneohe Bay, Oahu, displayed significant antimicrobial activity against methicillin-resistant Staphylococcus aureus. Bioassay-guided fractionation of the lipophilic extract led to the isolation and structure elucidation of two new highly brominated compounds, 2,3,5,7-tetrabromobenzofuro[3,2-b]pyrrole (1) and 4,4',6-tribromo-2,2'-biphenol (2). In addition, we have identified the known compounds pentabromopseudilin and bromophene. We describe the isolation and structure elucidation of the compounds 1 and 2 together with their antimicrobial activities against methicillin-resistant Staphylococcus aureus.

  7. Molecular investigation of the distribution, abundance and diversity of the genus Pseudoalteromonas in marine samples.

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    Skovhus, Torben L; Holmström, Carola; Kjelleberg, Staffan; Dahllöf, Ingela

    2007-08-01

    The genus Pseudoalteromonas has attracted interest because it has frequently been found in association with eukaryotic hosts, and because many Pseudoalteromonas species produce biologically active compounds. One distinct group of Pseudoalteromonas species is the antifouling subgroup containing Pseudoalteromonas tunicata and Ps. ulvae, which both produce extracellular compounds that inhibit growth and colonization by different marine organisms. PCR primers targeting the 16S rRNA gene of the genus Pseudoalteromonas and the antifouling subgroup were developed and applied in this study. Real-time quantitative PCR (qPCR) was applied to determine the relative bacterial abundance of the genus and the antifouling subgroup, and denaturing gradient gel electrophoresis (DGGE) was applied to study the diversity of the genus in 11 different types of marine samples from Danish coastal waters. The detection of Ps. tunicata that contain the antifouling subgroup was achieved through specific PCR amplification of the antibacterial protein gene (alpP). The Pseudoalteromonas species accounted for 1.6% of the total bacterial abundance across all samples. The Pseudoalteromonas diversity on the three unfouled marine organisms Ciona intestinalis, Ulva lactuca and Ulvaria fusca was found to be low, and Ps. tunicata was only detected on these three hosts, which all contain accessible cellulose polymers in their cell walls.

  8. Pseudoalteromonas strains are potent immunomodulators owing to low-stimulatory LPS

    DEFF Research Database (Denmark)

    Maaetoft-Udsen, Kristina; Vynne, Nikolaj Grønnegaard; Heegaard, Peter M. H.

    2013-01-01

    confirmed the involvement of LPS and TLR4 and established Pseudoalteromonas LPS as TLR4 antagonists. The isolated LPS was active in the endotoxin limulus amoebocyte lysate assay and capable of inducing increased endocytosis in DCs. This study highlights that antagonistic LPS from Pseudoalteromonas strains...... investigated with respect to their immunomodulatory properties in DCs. Both inhibited IL-12 and increased IL-10 production induced by E. coli LPS. LPS isolated from the two Pseudoalteromonas strains had characteristic lipid A bands in SDS-PAGE. Stimulation of HEK293 TLR4/MD2 cells with the isolated LPS...

  9. Terrimonas arctica sp. nov., isolated from Arctic tundra soil.

    Science.gov (United States)

    Jiang, Fan; Qiu, Xia; Chang, Xulu; Qu, Zhihao; Ren, Lvzhi; Kan, Wenjing; Guo, Youhao; Fang, Chengxiang; Peng, Fang

    2014-11-01

    A novel, Gram-stain-negative, aerobic, non-motile and rod-shaped bacterium, designated R9-86(T), was isolated from tundra soil collected near Ny-Ålesund, Svalbard Archipelago, Norway (78° N). Growth occurred at 4-28 °C (optimum, 22-25 °C) and at pH 6.0-9.0 (optimum, pH 7.0). Flexirubin-type pigments were absent. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain R9-86(T) belonged to the genus Terrimonas in the family Chitinophagaceae. 16S rRNA gene sequence similarities between strain R9-86(T) and the type strains of species of the genus Terrimonas with validly published names ranged from 93.7 to 95.0%. Strain R9-86(T) contained iso-C(15:1)-G (25.7%), iso-C(15:0) (24.5%), iso-C(17:0)-3OH (18.3%) and summed feature 3 (C(16:1)ω7c and/or C(16:1)ω6c, 8.7%) as its major cellular fatty acids; phosphatidylethanolamine and an unknown polar lipid as its main polar lipids, and MK-7 as its predominant respiratory quinone. The DNA G+C content was 48.4 mol%. On the basis of phenotypic, chemotaxonomic and phylogenetic data, strain R9-86(T) is considered to represent a novel species of the genus Terrimonas, for which the name Terrimonas arctica sp. nov. is proposed. The type strain is R9-86(T) ( =CCTCC AB 2011004(T) =NRRL B-59114(T)). © 2014 IUMS.

  10. The influence of goose grazing on the growth of Poa arctica : overestimation of overcompensation

    NARCIS (Netherlands)

    Loonen, MJJE

    The effect of grazing by barnacle geese (Branta leucopsis) on above-ground production was investigated on the Arctic tundra grass Poa arctica at Spitsbergen during the growing season of 1996. We applied three treatments: orated; whole season ungrazed and temporary ungrazed during the second half of

  11. Investigation of Li/Ca variations in aragonitic shells of the ocean quahog Arctica islandica, northeast Iceland

    National Research Council Canada - National Science Library

    Julien Thébault; Bernd R. Schöne; Nadine Hallmann; Matthias Barth; Elizabeth V. Nunn

    2009-01-01

      Interannual and intra-annual variations in lithium-to-calcium ratio were investigated with high temporal resolution in the aragonitic outer shell layer of juvenile Arctica islandica (Mollusca; Bivalvia...

  12. [Taxonomical study of bacteria from genera Alteromonas and Pseudoalteromonas isolated from Black Sea water and invertebrates].

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    Onyshchenko, O M; Kiprianova, O A; Rodriguez-Valera, F; Benlloch, S

    2005-01-01

    Nineteen (19) strains of bacteria have been isolated from the Black Sea water and invertebrates (mollusks and actinia). Most of them have been identified as Alteromonas macleodii, Pseudoalteromonas citrea and P. haloplanktis on the basis of polyphasic taxonomical analysis. Six strains showed 96-97 % similarity to 16S rRNA sequence of the known species of Pseudoalteromonas and obviously belonged to new species. The studied strains have been characterized by a wide spectrum of phenotypic features (morphology, enzyme activity, spectra of carbon nutrition, antibiotic sensitivity); high sensitivity of P. haloplanktis strains to cephalotin and resistance of A. macleodii strains to furadonin made them different than other studied strains of Alteromonas and Pseudoalteromonas.

  13. Sarcocystis arctica (Apicomplexa: Sarcocystidae): ultrastructural description and its new host record, the Alaskan wolf (Canis lupus).

    Science.gov (United States)

    Calero-Bernal, Rafael; Cerqueira-Cézar, Camila K; Verma, Shiv Kumar; Mowery, Joseph; Carmena, David; Beckmen, Kimberlee; Dubey, Jitender P

    2016-07-01

    Sarcocystis sarcocysts are common in muscles of herbivores but are rare in muscles of carnivores. Here, we report sarcocysts in the muscles of a gray wolf (Canis lupus) from Alaska, USA, for the first time. Sarcocysts extracted from the tongue of the wolf were up to 900 μm long and slender and appeared to have a relatively thin wall by light microscope. By transmission electron microscopy, the sarcocyst wall most closely resembled "type 9c," and had a wavy parasitophorous vacuolar membrane folded as pleomorphic villar protrusions (vp), with anastomoses of tips. The vp and the ground substance (gs) layer were smooth without tubules or granules. The gs was up to 2.0 μm thick. The total width of the wall including vp and the gs was 3.5 μm. The vp were up to 1.5 μm long. Mature sarcocysts contained numerous bradyzoites and few metrocytes. The bradyzoites were 9.5 μm long and 1.5 μm wide, and contained all organelles found in Sarcocystis bradyzoites with at least two rhoptries. Molecular characterization showed the highest identity for 18S rRNA, 28S rRNA, ITS-1, and cox1 sequences of Sarcocystis arctica of the Arctic fox (Vulpes lagopus) from Norway. The ultrastructure of S. arctica from the fox is unknown. Here, we provide ultrastructure of S. arctica from the Alaskan wolf for the first time. The definitive host of S. arctica remains unknown.

  14. Characterization of a cryptic plasmid pSM429 and its application for heterologous expression in psychrophilic Pseudoalteromonas

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    Chen Bo

    2011-05-01

    Full Text Available Abstract Background Pseudoalteromonas is an important genus widespread in marine environment, and a lot of psychrophilic Pseudoalteromonas strains thrive in deep sea and polar sea. By now, there are only a few genetic systems for Pseudoalteromonas reported and no commercial Pseudoalteromonas genetic system is available, which impedes the study of Pseudoalteromonas, especially for psychrophilic strains. The aim of this study is to develop a heterologous expression system for psychrophilic Pseudoalteromonas. Results A cryptic plasmid pSM429 isolated from psychrophilic Pseudoalteromonas sp. BSi20429 from the Arctic sea ice, was sequenced and characterized. The plasmid pSM429 is 3874 bp in length, with a G+C content of 28%. Four putative open reading frames (ORFs were identified on pSM429. Based on homology, the ORF4 was predicted to encode a replication initiation (Rep protein. A shuttle vector (Escherichia coli, Pseudoalteromonas, pWD, was constructed by ligating pSM429 and pUC19 and inserting a chloramphenicol acetyl transferase (CAT cassette conferring chloramphenicol resistance. To determine the minimal replicon of pSM429 and to check the functionality of identified ORFs, various pWD derivatives were constructed. All derivatives except the two smallest ones were shown to allow replication in Pseudoalteromonas sp. SM20429, a plasmid-cured strain of Pseudoalteromonas sp. BSi20429, suggesting that the orf4 and its flanking intergenic regions are essential for plasmid replication. Although not essential, the sequence including some repeats between orf1 and orf2 plays important roles in segregational stability of the plasmid. With the aid of pWD-derived plasmid pWD2, the erythromycin resistance gene and the cd gene encoding the catalytic domain of a cold-adapted cellulase were successfully expressed in Pseudoalteromonas sp. SM20429. Conclusions Plasmid pSM429 was isolated and characterized, and the regions essential for plasmid replication and

  15. Lea protein expression during cold-induced dehydration in the Arctic collembola Megaphorura arctica

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    Popović Ž.D.

    2011-01-01

    Full Text Available The Arctic springtail Megaphorura arctica (Tullberg, 1876 employs a strategy known as cryoprotective dehydration to survive winter temperatures as low as -25°C. During cryoprotective dehydration, water is lost from the animal to ice in its surroundings as a result of the difference in vapour pressure between the animal’s supercooled body fluids and ice (Worland et al., 1998; Holmstrup and Somme, 1998. This mechanism ensures that as the habitat temperature falls, the concentration of solutes remains high enough to prevent freezing (Holmstrup et al., 2002. In M. arctica, accumulation of trehalose, a cryo/anhydro protectant, occurs in parallel with dehydration. Recent studies have identified a number of genes and cellular processes involved in cryoprotective dehydration in M. arctica (Clark et al., 2007; Clark et al., 2009; Purać et al., 2011. One of them includes late embryogenesis abundant (LEA proteins. This study, together with that of Bahrndorff et al. (2008, suggests that LEA proteins may be involved in protective dehydration in this species.

  16. Genome Sequences of Two Pseudoalteromonas Strains Isolated from the South China Sea

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    Zeng, Zhenshun; Dai, Shikun; Xie, Yunchang; Tian, Xinpeng; Li, Jie

    2014-01-01

    Two Pseudoalteromonas strains, SCSIO 04301 and SCSIO 11900, were isolated from the South China Sea, and both strains form biofilms. Here we present the draft genome sequences of these two strains, which will aid the study of marine microbes that are adapted to marine sediments or are associated with eukaryotic hosts. PMID:24744335

  17. Draft Genome Sequence of the Moderately Halophilic Bacterium Pseudoalteromonas ruthenica Strain CP76.

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    de la Haba, Rafael R; Sánchez-Porro, Cristina; León, María José; Papke, R Thane; Ventosa, Antonio

    2013-05-23

    Pseudoalteromonas ruthenica strain CP76, isolated from a saltern in Spain, is a moderately halophilic bacterium belonging to the Gammaproteobacteria. Here we report the draft genome sequence, which consists of a 4.0-Mb chromosome, of this strain, which is able to produce the extracellular enzyme haloprotease CPI.

  18. MALDI-TOF Mass Spectrometry Discriminates Known Species and Marine Environmental Isolates of Pseudoalteromonas

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    Emami, Kaveh; Nelson, Andrew; Hack, Ethan; Zhang, Jinwei; Green, David H.; Caldwell, Gary S.; Mesbahi, Ehsan

    2016-01-01

    The genus Pseudoalteromonas constitutes an ecologically significant group of marine Gammaproteobacteria with potential biotechnological value as producers of bioactive compounds and of enzymes. Understanding their roles in the environment and bioprospecting for novel products depend on efficient ways of identifying environmental isolates. Matrix Assisted Laser Desorption/Ionization-Time of Flight Mass Spectrometry (MALDI-TOF MS) biotyping has promise as a rapid and reliable method of identifying and distinguishing between different types of bacteria, but has had relatively limited application to marine bacteria and has not been applied systematically to Pseudoalteromonas. Therefore, we constructed a MALDI-TOF MS database of 31 known Pseudoalteromonas species, to which new isolates can be compared by MALDI-TOF biotyping. The ability of MALDI-TOF MS to distinguish between species was scrutinized by comparison with 16S rRNA gene sequencing. The patterns of similarity given by the two approaches were broadly but not completely consistent. In general, the resolution of MALDI-TOF MS was greater than that of 16S rRNA gene sequencing. The database was tested with 13 environmental Pseudoalteromonas isolates from UK waters. All of the test strains could be identified to genus level by MALDI-TOF MS biotyping, but most could not be definitely identified to species level. We conclude that several of these isolates, and possibly most, represent new species. Thus, further taxonomic investigation of Pseudoalteromonas is needed before MALDI-TOF MS biotyping can be used reliably for species identification. It is, however, a powerful tool for characterizing and distinguishing among environmental isolates and can make an important contribution to taxonomic studies. PMID:26903983

  19. Surviving the cold: molecular analyses of insect cryoprotective dehydration in the Arctic springtail Megaphorura arctica (Tullberg

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    Popović Željko D

    2009-07-01

    Full Text Available Abstract Background Insects provide tractable models for enhancing our understanding of the physiological and cellular processes that enable survival at extreme low temperatures. They possess three main strategies to survive the cold: freeze tolerance, freeze avoidance or cryoprotective dehydration, of which the latter method is exploited by our model species, the Arctic springtail Megaphorura arctica, formerly Onychiurus arcticus (Tullberg 1876. The physiological mechanisms underlying cryoprotective dehydration have been well characterised in M. arctica and to date this process has been described in only a few other species: the Antarctic nematode Panagrolaimus davidi, an enchytraied worm, the larvae of the Antarctic midge Belgica antarctica and the cocoons of the earthworm Dendrobaena octaedra. There are no in-depth molecular studies on the underlying cold survival mechanisms in any species. Results A cDNA microarray was generated using 6,912 M. arctica clones printed in duplicate. Analysis of clones up-regulated during dehydration procedures (using both cold- and salt-induced dehydration has identified a number of significant cellular processes, namely the production and mobilisation of trehalose, protection of cellular systems via small heat shock proteins and tissue/cellular remodelling during the dehydration process. Energy production, initiation of protein translation and cell division, plus potential tissue repair processes dominate genes identified during recovery. Heat map analysis identified a duplication of the trehalose-6-phosphate synthase (TPS gene in M. arctica and also 53 clones co-regulated with TPS, including a number of membrane associated and cell signalling proteins. Q-PCR on selected candidate genes has also contributed to our understanding with glutathione-S-transferase identified as the major antioxdidant enzyme protecting the cells during these stressful procedures, and a number of protein kinase signalling molecules

  20. Local variability in growth and reproduction of Salix arctica in the High Arctic

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    Noémie Boulanger-Lapointe

    2016-06-01

    Full Text Available Arctic terrestrial ecosystems are heterogeneous because of the strong influences of microtopography, soil moisture and snow accumulation on vegetation distribution. The interaction between local biotic and abiotic factors and global climate patterns will influence species responses to climate change. Salix arctica (Arctic willow is a structuring species, ubiquitous and widespread, and as such is one of the most important shrub species in the High Arctic. In this study, we measured S. arctica reproductive effort, early establishment, survival and growth in the Zackenberg valley, north-east Greenland. We sampled four plant communities that varied with respect to snow conditions, soil moisture, nutrient content and plant composition. We found large variability in reproductive effort and success with total catkin density ranging from 0.6 to 66 catkins/m2 and seedling density from <1 to 101 seedlings/m2. There were also major differences in crown area increment (4–23 cm2/year and stem radial growth (40–74 µm/year. The snowbed community, which experienced a recent reduction in snow cover, supported young populations with high reproductive effort, establishment and growth. Soil nutrient content and herbivore activity apparently did not strongly constrain plant reproduction and growth, but competition by Cassiope tetragona and low soil moisture may inhibit performance. Our results show that local environmental factors, such as snow accumulation, have a significant impact on tundra plant response to climate change and will affect the understanding of regional vegetation response to climate change.

  1. Volatile compounds associated with Psychrobacter spp. and Pseudoalteromonas spp., the dominant microbiota of brown shrimp (Crangon crangon) during aerobic storage.

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    Broekaert, Katrien; Noseda, Bert; Heyndrickx, Marc; Vlaemynck, Geertrui; Devlieghere, Frank

    2013-09-16

    The spoilage potential of several Psychrobacter and Pseudoalteromonas species (Psychrobacter cibarius, Psychrobacter maritimus, Pseudoalteromonas elyakovii, Pseudoalteromonas paragorgicola and Pseudoalteromonas nigrifaciens) was determined and quantified based on the presence of volatile organic compounds (VOCs). Psychrobacter and Pseudoalteromonas species dominate the microbiota of cooked brown shrimp (Crangon crangon). Additionally, API ZYM analyses determined the species' enzymatic capacity to contribute to spoilage by degrading lipids, amino acids and proteins. The bacterial species used in this study were isolated from cooked brown shrimp during storage under different storage and processing conditions and were selected for analysis of their spoilage potential based on their difference in the (GTG)₅-rep profile, 16S rRNA and gyrB sequences and API ZYM profile. The isolates were inoculated as pure cultures on heat-sterilised shrimp. The inoculated samples were stored at 4 °C and the production of VOCs by the pure strains on the shrimp matrix was identified via gas chromatography coupled to mass spectrometry (GC-MS). VOC production was quantified daily by selected ion flow tube mass spectrometry (SIFT-MS) until the bacterial count exceeded 10⁸-10⁹ cfu/g. The sensory profile of Psychrobacter species revealed very low spoilage potential as measured by the production of VOCs, but these species may nevertheless contribute to spoilage. Based on the API ZYM results, Pseudoalteromonas as well as Psychrobacter species might enhance spoilage by breaking down lipids and hydrolysing amino acids and proteins. Pseudoalteromonas species, especially Psa. elyakovii and Psa. nigrifaciens, have a high spoilage potential and might be responsible for the off-odours produced during spoilage of brown shrimp. These isolates produced significant amounts of volatile compounds such as sulphides, acetone, ammonia, and ethanol, which are all involved in seafood spoilage. © 2013

  2. Comparative Omics and Trait Analyses of Marine Pseudoalteromonas Phages Advance the Phage OTU Concept

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    Melissa B. Duhaime

    2017-07-01

    Full Text Available Viruses influence the ecology and evolutionary trajectory of microbial communities. Yet our understanding of their roles in ecosystems is limited by the paucity of model systems available for hypothesis generation and testing. Further, virology is limited by the lack of a broadly accepted conceptual framework to classify viral diversity into evolutionary and ecologically cohesive units. Here, we introduce genomes, structural proteomes, and quantitative host range data for eight Pseudoalteromonas phages isolated from Helgoland (North Sea, Germany and use these data to advance a genome-based viral operational taxonomic unit (OTU definition. These viruses represent five new genera and inform 498 unaffiliated or unannotated protein clusters (PCs from global virus metagenomes. In a comparison of previously sequenced Pseudoalteromonas phage isolates (n = 7 and predicted prophages (n = 31, the eight phages are unique. They share a genus with only one other isolate, Pseudoalteromonas podophage RIO-1 (East Sea, South Korea and two Pseudoalteromonas prophages. Mass-spectrometry of purified viral particles identified 12–20 structural proteins per phage. When combined with 3-D structural predictions, these data led to the functional characterization of five previously unidentified major capsid proteins. Protein functional predictions revealed mechanisms for hijacking host metabolism and resources. Further, they uncovered a hybrid sipho-myovirus that encodes genes for Mu-like infection rarely described in ocean systems. Finally, we used these data to evaluate a recently introduced definition for virus populations that requires members of the same population to have >95% average nucleotide identity across at least 80% of their genes. Using physiological traits and genomics, we proposed a conceptual model for a viral OTU definition that captures evolutionarily cohesive and ecologically distinct units. In this trait-based framework, sensitive hosts are

  3. Ambient UV-B radiation reduces PSII performance and net photosynthesis in high Arctic Salix arctica

    DEFF Research Database (Denmark)

    Albert, Kristian Rost; Mikkelsen, Teis Nørgaard; Ro-Poulsen, Helge

    2011-01-01

    Ambient ultraviolet-B (UV-B) radiation potentially impacts the photosynthetic performance of high Arctic plants. We conducted an UV-B exclusion experiment in a dwarf shrub heath in NE Greenland (74°N), with open control, filter control, UV-B filtering and UV-AB filtering, all in combination......, nitrogen and UV-B absorbing compounds. Compared to a 60% reduced UV-B irradiance, the ambient solar UV-B reduced net photosynthesis in Salix arctica leaves fixed in the 45° position which exposed leaves to maximum natural irradiance. Also a reduced Calvin Cycle capacity was found, i.e. the maximum rate...... across position in the vegetation. These findings add to the evidence that the ambient solar UV-B currently is a significant stress factor for plants in high Arctic Greenland....

  4. Ambient UV-B radiation reduces PSII performance and net photosynthesis in high Arctic Salix arctica

    DEFF Research Database (Denmark)

    Albert, Kristian Rost; Mikkelsen, Teis Nørgaard; Ro-Poulsen, H.

    2011-01-01

    Ambient ultraviolet-B (UV-B) radiation potentially impacts the photosynthetic performance of high Arctic plants. We conducted an UV-B exclusion experiment in a dwarf shrub heath in NE Greenland (74°N), with open control, filter control, UV-B filtering and UV-AB filtering, all in combination...... was characterized by simultaneous gas exchange and chlorophyll fluorescence measurements and the PSII performance through the growing season was investigated with fluorescence measurements. Leaf harvest towards the end of the growing season was done to determine the specific leaf area and the content of carbon......, nitrogen and UV-B absorbing compounds. Compared to a 60% reduced UV-B irradiance, the ambient solar UV-B reduced net photosynthesis in Salix arctica leaves fixed in the 45° position which exposed leaves to maximum natural irradiance. Also a reduced Calvin Cycle capacity was found, i.e. the maximum rate...

  5. Marine Bacteria from Danish Coastal Waters Show Antifouling Activity against the Marine Fouling Bacterium Pseudoalteromonas sp. Strain S91 and Zoospores of the Green Alga Ulva australis Independent of Bacteriocidal Activity

    DEFF Research Database (Denmark)

    Bernbom, Nete; Ng, Yoke Yin; Kjelleberg, Staffan

    2011-01-01

    bacteria were significantly higher in warmer than in colder months. While some species were isolated at all sampling locations, others were niche specific. We repeatedly isolated Phaeobacter gallaeciensis at surfaces from one site and Pseudoalteromonas tunicata at two others. Twenty-two strains...... the number of strain S91 or Ulva spores attaching to a preformed biofilm of each of the 22 strains. The strongest antifouling activity was found in Pseudoalteromonas strains. Biofilms of Pseudoalteromonas piscicida, Pseudoalteromonas tunicata, and Pseudoalteromonas ulvae prevented Pseudoalteromonas S91 from...... attaching to steel surfaces. P. piscicida killed S91 bacteria in the suspension cultures, whereas P. tunicata and P. ulvae did not; however, they did prevent adhesion by nonbactericidal mechanism(s). Seven Pseudoalteromonas species, including P. piscicida and P. tunicata, reduced the number of settling Ulva...

  6. Bioactive Compound Synthetic Capacity and Ecological Significance of Marine Bacterial Genus Pseudoalteromonas

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    John P. Bowman

    2007-12-01

    Full Text Available The genus Pseudoalteromonas is a marine group of bacteria belonging to theclass Gammaproteobacteria that has come to attention in the natural product andmicrobial ecology science fields in the last decade. Pigmented species of the genus havebeen shown to produce an array of low and high molecular weight compounds withantimicrobial, anti-fouling, algicidal and various pharmaceutically-relevant activities.Compounds formed include toxic proteins, polyanionic exopolymers, substitutedphenolic and pyrolle-containing alkaloids, cyclic peptides and a range of bromine-substituted compounds. Ecologically, Pseudoalteromonas appears significant and to datehas been shown to influence biofilm formation in various marine econiches; involved inpredator-like interactions within the microbial loop; influence settlement, germinationand metamorphosis of various invertebrate and algal species; and may also be adopted bymarine flora and fauna as defensive agents. Studies have been so far limited to arelatively small subset of strains compared to the known diversity of the genussuggesting that many more discoveries of novel natural products as well as ecologicalconnections these may have in the marine ecosystem remain to be made.

  7. Bioactivity, Chemical Profiling, and 16S rRNA-Based Phylogeny of Pseudoalteromonas Strains Collected on a Global Research Cruise

    DEFF Research Database (Denmark)

    Vynne, Nikolaj Grønnegaard; Månsson, Maria; Nielsen, Kristian Fog

    2011-01-01

    One hundred one antibacterial Pseudoalteromonas strains that inhibited growth of a Vibrio anguillarum test strain were collected on a global research cruise (Galathea 3), and 51 of the strains repeatedly demonstrated antibacterial activity. Here, we profile secondary metabolites of these strains ...

  8. The Haloprotease CPI Produced by the Moderately Halophilic Bacterium Pseudoalteromonas ruthenica Is Secreted by the Type II Secretion Pathway▿ †

    Science.gov (United States)

    Sánchez-Porro, Cristina; Mellado, Encarnación; Pugsley, Anthony P.; Francetic, Olivera; Ventosa, Antonio

    2009-01-01

    The gene (cpo) encoding the extracellular protease CPI produced by the moderately halophilic bacterium Pseudoalteromonas ruthenica CP76 was cloned, and its nucleotide sequence was analyzed. The cpo gene encodes a 733-residue protein showing sequence similarity to metalloproteases of the M4 family. The type II secretion apparatus was shown to be responsible for secretion of the haloprotease CPI. PMID:19376897

  9. A Large Ornithurine Bird (Tingmiatornis arctica) from the Turonian High Arctic: Climatic and Evolutionary Implications

    Science.gov (United States)

    Bono, Richard K.; Clarke, Julia; Tarduno, John A.; Brinkman, Donald

    2016-12-01

    Bird fossils from Turonian (ca. 90 Ma) sediments of Axel Heiberg Island (High Canadian Arctic) are among the earliest North American records. The morphology of a large well-preserved humerus supports identification of a new volant, possibly diving, ornithurine species (Tingmiatornis arctica). The new bird fossils are part of a freshwater vertebrate fossil assemblage that documents a period of extreme climatic warmth without seasonal ice, with minimum mean annual temperatures of 14 °C. The extreme warmth allowed species expansion and establishment of an ecosystem more easily able to support large birds, especially in fresh water bodies such as those present in the Turonian High Arctic. Review of the high latitude distribution of Northern Hemisphere Mesozoic birds shows only ornithurine birds are known to have occupied these regions. We propose physiological differences in ornithurines such as growth rate may explain their latitudinal distribution especially as temperatures decline later in the Cretaceous. Distribution and physiology merit consideration as factors in their preferential survival of parts of one ornithurine lineage, Aves, through the K/Pg boundary.

  10. A Distinct Mitochondrial Genome with DUI-Like Inheritance in the Ocean Quahog Arctica islandica.

    Science.gov (United States)

    Dégletagne, Cyril; Abele, Doris; Held, Christoph

    2016-02-01

    Mitochondrial DNA (mtDNA) is strictly maternally inherited in metazoans. The major exception to this rule has been found in many bivalve species which allow the presence of different sex-linked mtDNA molecules. This mechanism, named doubly uniparental inheritance (DUI), is characterized by the presence of two mtDNAs: The female mtDNA is found in somatic tissue and female gonads, whereas the male mtDNA is usually found in male gonads and sperm. In this study we highlight the existence of two divergent mitochondrial haplotypes with a low genetic difference around 6-8% in Arctica islandica, a long-lived clam belonging to the Arcticidae, a sister group to the Veneridae in which DUI has been found. Phylogenetic analysis on cytochrome b and 16S sequences from somatic and gonadic tissues of clams belonging to different populations reveals the presence of the "divergent" type in male gonads only and the "normal" type in somatic tissues and female gonads. This peculiar segregation of divergent mtDNA types speaks for the occurrence of the DUI mechanism in A. islandica. This example also highlights the difficulties to assess the presence of such particular mitochondrial inheritance system and underlines the possible misinterpretations in phylogeographic and phylogenetic studies of bivalve species linked to the presence of two poorly differentiated mitochondrial genomes. © The Author 2015. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

  11. Pseudoalteromonas spp. Serve as Initial Bacterial Attractants in Mesocosms of Coastal Waters but Have Subsequent Antifouling Capacity in Mesocosms and when Embedded in Paint

    DEFF Research Database (Denmark)

    Bernbom, Nete; Ng, Yin; Møller, Stefan

    2013-01-01

    . Pseudoalteromonas piscicida survived on a steel surface and retained antifouling activity for at least 53 days in sterile seawater, whereas P. tunicata survived and had antifouling activity for only 1 week. However, during the first week, all Pseudoalteromonas strains facilitated rather than prevented bacterial...... cells/cm2. However, after 53 days, seven of eight Pseudoalteromonas strains had reduced total bacterial adhesion compared to the control. P. piscicida, P. antarctica, and P. ulvae remained on the surface, at levels similar to those in the initial coating, whereas P. tunicata could not be detected....... Larger fouling organisms were observed on all plates precoated with Pseudoalteromonas; however, plates coated only with sterile growth medium were dominated by a bacterial biofilm. Suspensions of a P. piscicida strain and a P. tunicata strain were incorporated into ship paints (Hempasil x3 87500...

  12. Adverse Effects of Immobilised Pseudoalteromonas on the Fish Pathogenic Vibrio anguillarum: An In Vitro Study

    Directory of Open Access Journals (Sweden)

    Wiebke Wesseling

    2016-01-01

    Full Text Available As a prerequisite for use in marine aquaculture, two immobilisation systems were developed by employing the probiotic bacterium Pseudoalteromonas sp. strain MLms_gA3. Their impact on the survivability of the fish pathogen Vibrio anguillarum was explored. Probiotic bacteria either grown as a biofilm on ceramic tiles or embedded in alginate beads were added to sterile artificial seawater that contained the fish pathogen. While immobilisation on ceramics followed a recently developed protocol, a medium allowing for alginate microencapsulation was newly developed. Anti-Vibrio activities were obtained with both immobilisation systems. The viable cell counts of V. anguillarum constantly decreased within the first two weeks of the treatments evidencing the potential of the immobilisation systems for providing probiotic-based protection against this pathogen.

  13. Induction of larval metamorphosis of the coral Acropora millepora by tetrabromopyrrole isolated from a Pseudoalteromonas bacterium.

    Directory of Open Access Journals (Sweden)

    Jan Tebben

    Full Text Available The induction of larval attachment and metamorphosis of benthic marine invertebrates is widely considered to rely on habitat specific cues. While microbial biofilms on marine hard substrates have received considerable attention as specific signals for a wide and phylogenetically diverse array of marine invertebrates, the presumed chemical settlement signals produced by the bacteria have to date not been characterized. Here we isolated and fully characterized the first chemical signal from bacteria that induced larval metamorphosis of acroporid coral larvae (Acropora millepora. The metamorphic cue was identified as tetrabromopyrrole (TBP in four bacterial Pseudoalteromonas strains among a culture library of 225 isolates obtained from the crustose coralline algae Neogoniolithon fosliei and Hydrolithon onkodes. Coral planulae transformed into fully developed polyps within 6 h, but only a small proportion of these polyps attached to the substratum. The biofilm cell density of the four bacterial strains had no influence on the ratio of attached vs. non-attached polyps. Larval bioassays with ethanolic extracts of the bacterial isolates, as well as synthetic TBP resulted in consistent responses of coral planulae to various doses of TBP. The lowest bacterial density of one of the Pseudoalteromonas strains which induced metamorphosis was 7,000 cells mm(-2 in laboratory assays, which is on the order of 0.1-1% of the total numbers of bacteria typically found on such surfaces. These results, in which an actual cue from bacteria has been characterized for the first time, contribute significantly towards understanding the complex process of acroporid coral larval settlement mediated through epibiotic microbial biofilms on crustose coralline algae.

  14. Discovery of a novel iota carrageenan sulfatase isolated from the marine bacterium Pseudoalteromonas carrageenovora

    Directory of Open Access Journals (Sweden)

    Sabine Marie Genicot

    2014-08-01

    Full Text Available Carrageenans are sulfated polysaccharides extracted from the cell wall of some marine red algae. These polysaccharides are widely used as gelling, stabilizing, and viscosifying agents in the food and pharmaceutical industries. Since the rheological properties of these polysaccharides depend on their sulfate content, we screened several isolated marine bacteria for carrageenan specific sulfatase activity, in the aim of developing enzymatic bioconversion of carrageenans. As a result of the screening, an iota-carrageenan sulfatase was detected in the cell-free lysate of the marine bacterium Pseudoalteromonas carrageenovora strain PscT. It was purified through Phenyl Sepharose and Diethylaminoethyl Sepharose chromatography. The pure enzyme, Psc -CgsA, was characterized. It had a molecular weight of 115.9 kDaltons and exhibited an optimal activity/stability at pH ~8.3 and at 40°C ± 5°C. It was inactivated by phenylmethylsulfonyl fluoride but not by ethylene diamine tetraacetic acid. Psc -CgsA specifically catalyzes the hydrolysis of the 4-S sulfate of iota-carrageenan. The purified enzyme could transform iota-carrageenan into hybrid iota-/alpha- or pure alpha-carrageenan under controlled conditions. The gene encoding Psc -CgsA, a protein of 1038 amino acids, was cloned into Escherichia coli, and the sequence analysis revealed that Psc -CgsA has more than 90% sequence identity with a putative uncharacterized protein Q3IKL4 from the marine strain Pseudoalteromonas haloplanktis TAC 125, but besides this did not share any homology to characterized sulfatases. Phylogenetic studies show that P. carrageenovora sulfatase thus represents the first characterized member of a new sulfatase family, with a C-terminal domain having strong similarity with the superfamily of amidohydrolases, highlighting the still unexplored diversity of marine polysaccharide modifying enzymes.

  15. Biofilm Formation and Heat Stress Induce Pyomelanin Production in Deep-Sea Pseudoalteromonas sp. SM9913

    Directory of Open Access Journals (Sweden)

    Zhenshun Zeng

    2017-09-01

    Full Text Available Pseudoalteromonas is an important bacterial genus present in various marine habitats. Many strains of this genus are found to be surface colonizers on marine eukaryotes and produce a wide range of pigments. However, the exact physiological role and mechanism of pigmentation were less studied. Pseudoalteromonas sp. SM9913 (SM9913, an non-pigmented strain isolated from the deep-sea sediment, formed attached biofilm at the solid–liquid interface and pellicles at the liquid–air interface at a wide range of temperatures. Lower temperatures and lower nutrient levels promoted the formation of attached biofilm, while higher nutrient levels promoted pellicle formation of SM9913. Notably, after prolonged incubation at higher temperatures growing planktonically or at the later stage of the biofilm formation, we found that SM9913 released a brownish pigment. By comparing the protein profile at different temperatures followed by qRT-PCR, we found that the production of pigment at higher temperatures was due to the induction of melA gene which is responsible for the synthesis of homogentisic acid (HGA. The auto-oxidation of HGA can lead to the formation of pyomelanin, which has been shown in other bacteria. Fourier Transform Infrared Spectrometer analysis confirmed that the pigment produced in SM9913 was pyomelanin-like compound. Furthermore, we demonstrated that, during heat stress and during biofilm formation, the induction level of melA gene was significantly higher than that of the hmgA gene which is responsible for the degradation of HGA in the L-tyrosine catabolism pathway. Collectively, our results suggest that the production of pyomelanin of SM9913 at elevated temperatures or during biofilm formation might be one of the adaptive responses of marine bacteria to environmental cues.

  16. The effects of environment on Arctica islandica shell formation and architecture

    Science.gov (United States)

    Milano, Stefania; Nehrke, Gernot; Wanamaker, Alan D., Jr.; Ballesta-Artero, Irene; Brey, Thomas; Schöne, Bernd R.

    2017-03-01

    Mollusks record valuable information in their hard parts that reflect ambient environmental conditions. For this reason, shells can serve as excellent archives to reconstruct past climate and environmental variability. However, animal physiology and biomineralization, which are often poorly understood, can make the decoding of environmental signals a challenging task. Many of the routinely used shell-based proxies are sensitive to multiple different environmental and physiological variables. Therefore, the identification and interpretation of individual environmental signals (e.g., water temperature) often is particularly difficult. Additional proxies not influenced by multiple environmental variables or animal physiology would be a great asset in the field of paleoclimatology. The aim of this study is to investigate the potential use of structural properties of Arctica islandica shells as an environmental proxy. A total of 11 specimens were analyzed to study if changes of the microstructural organization of this marine bivalve are related to environmental conditions. In order to limit the interference of multiple parameters, the samples were cultured under controlled conditions. Three specimens presented here were grown at two different water temperatures (10 and 15 °C) for multiple weeks and exposed only to ambient food conditions. An additional eight specimens were reared under three different dietary regimes. Shell material was analyzed with two techniques; (1) confocal Raman microscopy (CRM) was used to quantify changes of the orientation of microstructural units and pigment distribution, and (2) scanning electron microscopy (SEM) was used to detect changes in microstructural organization. Our results indicate that A. islandica microstructure is not sensitive to changes in the food source and, likely, shell pigment are not altered by diet. However, seawater temperature had a statistically significant effect on the orientation of the biomineral. Although

  17. Connections between the growth of Arctica islandica and phytoplankton dynamics on the Faroe Shelf

    Science.gov (United States)

    Bonitz, Fabian; Andersson, Carin; Trofimova, Tamara

    2017-04-01

    In this study we use molluscan sclerochronological techniques in order to obtain closer insights into environmental and ecological dynamics of Faroe Shelf waters. The Faroe Shelf represents a special ecosystem with rich benthic and neritic communities, which also have great importance for many economically relevant fish stocks. Thus, a better understanding of seasonal and year-to-year phytoplankton and stratification dynamics would be useful because they also have implications for higher trophic levels. The water masses of the Faroe Shelf are fairly homogenous and isolated from off-shelf waters but at a certain depth, which is referred to as transition zone, seasonal stratification and horizontal exchange occur. Systematic observations and phytoplankton dynamic investigations have only been performed during the last 29 years but longer records are missing. Thus, we use the growth increment variability in long-lived Arctica islandica shells from the transition zone of the eastern Faroe Shelf to evaluate its potential to estimate on-shelf phytoplankton and stratification dynamics since previous studies have shown that the growth of A. islandica is highly dependent on food availability. We have built a shell-based master-chronology reaching back to the 17th century. Comparisons between the growth indices of our chronology and fluorescence data reveal significant positive relationships. In combination with an index that accounts for stratification even stronger correlations are obtained. This indicates that the growth of A. islandica is largely influenced by a combination of how much phytoplankton is produced and how much actually reaches the bottom, i.e. how well-mixed the water column is. Further significant positive correlations can also be found between the growth indices and other primary productivity data from the Faroe Shelf. In conclusion, our results suggest that the growth indices can be related to year-to-year changes in phytoplankton production and

  18. Elevated CO₂ levels do not affect the shell structure of the bivalve Arctica islandica from the Western Baltic.

    Directory of Open Access Journals (Sweden)

    Kristina Stemmer

    Full Text Available Shells of the bivalve Arctica islandica are used to reconstruct paleo-environmental conditions (e.g. temperature via biogeochemical proxies, i.e. biogenic components that are related closely to environmental parameters at the time of shell formation. Several studies have shown that proxies like element and isotope-ratios can be affected by shell growth and microstructure. Thus it is essential to evaluate the impact of changing environmental parameters such as high pCO2 and consequent changes in carbonate chemistry on shell properties to validate these biogeochemical proxies for a wider range of environmental conditions. Growth experiments with Arctica islandica from the Western Baltic Sea kept under different pCO2 levels (from 380 to 1120 µatm indicate no affect of elevated pCO2 on shell growth or crystal microstructure, indicating that A. islandica shows an adaptation to a wider range of pCO2 levels than reported for other species. Accordingly, proxy information derived from A. islandica shells of this region contains no pCO2 related bias.

  19. Bacterial recovery and recycling of tellurium from tellurium-containing compounds by Pseudoalteromonas sp. EPR3.

    Science.gov (United States)

    Bonificio, W D; Clarke, D R

    2014-11-01

    Tellurium-based devices, such as photovoltaic (PV) modules and thermoelectric generators, are expected to play an increasing role in renewable energy technologies. Tellurium, however, is one of the scarcest elements in the earth's crust, and current production and recycling methods are inefficient and use toxic chemicals. This study demonstrates an alternative, bacterially mediated tellurium recovery process. We show that the hydrothermal vent microbe Pseudoalteromonas sp. strain EPR3 can convert tellurium from a wide variety of compounds, industrial sources and devices into metallic tellurium and a gaseous tellurium species. These compounds include metallic tellurium (Te(0)), tellurite (TeO3(2-)), copper autoclave slime, tellurium dioxide (TeO2), tellurium-based PV material (cadmium telluride, CdTe) and tellurium-based thermoelectric material (bismuth telluride, Bi2Te3). Experimentally, this was achieved by incubating these tellurium sources with the EPR3 in both solid and liquid media. Despite the fact that many of these tellurium compounds are considered insoluble in aqueous solution, they can nonetheless be transformed by EPR3, suggesting the existence of a steady state soluble tellurium concentration during tellurium transformation. These experiments provide insights into the processes of tellurium precipitation and volatilization by bacteria, and their implications on tellurium production and recycling. © 2014 The Society for Applied Microbiology.

  20. Accelerator Analysis of Tributyltin Adsorbed onto the Surface of a Tributyltin Resistant Marine Pseudoalteromonas sp. Cell

    Directory of Open Access Journals (Sweden)

    Akira Kitamura

    2008-10-01

    Full Text Available Tributyltin (TBT released into seawater from ship hulls is a stable marine pollutant and obviously remains in marine environments. We isolated a TBT resistant marine Pseudoalteromonas sp. TBT1 from sediment of a ship’s ballast water. The isolate (109.3 ± 0.2 colony-forming units mL-1 adsorbed TBT in proportion to the concentrations of TBTCl externally added up to 3 mM, where the number of TBT adsorbed by a single cell was estimated to be 108.2. The value was reduced to about one-fifth when the lysozyme-treated cells were used. The surface of ethanol treated cells became rough, but the capacity of TBT adsorption was the same as that for native cells. These results indicate that the function of the cell surface, rather than that structure, plays an important role to the adsorption of TBT. The adsorption state of TBT seems to be multi-layer when the number of more than 106.8 TBT molecules is adsorbed by a single cell.

  1. Cloning, expression and characterization of a lipase gene from marine bacterium Pseudoalteromonas lipolytica SCSIO 04301

    Science.gov (United States)

    Su, Hongfei; Mai, Zhimao; Zhang, Si

    2016-12-01

    A lipase gene, lip1233, isolated from Pseudoalteromonas lipolytica SCSIO 04301, was cloned and expressed in E. coli. The enzyme comprised 810 amino acid residues with a deduced molecular weight of 80 kDa. Lip1233 was grouped into the lipase family X because it contained a highly conserved motif GHSLG. The recombinant enzyme was purified with Ni-NTA affinity chromatography. The optimal temperature and pH value of Lip1233 were 45°C and 8.0, respectively. It retained more than 70% of original activity after being incubated in pH ranging from 6.0 to 9.5 for 30 min. It was stable when the temperature was below 45°C, but was unstable when the temperature was above 55°C. Most metal ions tested had no significant effect on the activity of Lip1233. Lip1233 remained more than original activity in some organic solvents at the concentration of 30% (v/v). It retained more than 30% activity after incubated in pure organic solvents for 12 h, while in hexane the activity was nearly 100%. Additionally, Lip1233 exhibited typical halotolerant characteristic as it was active under 4M NaCl. Lip1233 powder could catalyze efficiently the synthesis of fructose esters in hexane at 40°C. These characteristics demonstrated that Lip1233 is applicable to elaborate food processing and organic synthesis.

  2. Exopolysaccharides play a role in the swarming of the benthic bacterium Pseudoalteromonas sp. SM9913

    Directory of Open Access Journals (Sweden)

    Ang eLiu

    2016-04-01

    Full Text Available Most marine bacteria secrete exopolysaccharide (EPS, which is important for bacterial survival in the marine environment. However, it is still unclear whether the self-secreted EPS is involved in marine bacterial motility. Here we studied the role of EPS in the lateral flagella-driven swarming motility of benthic bacterium Pseudoalteromonas sp. SM9913 (SM9913 by a comparison of wild SM9913 and ΔepsT, an EPS synthesis defective mutant. Reduction of EPS production in ΔepsT did not affect the growth rate or the swimming motility, but significantly decreased the swarming motility on a swarming plate, suggesting that the EPS may play a role in SM9913 swarming. However, the expression and assembly of lateral flagella in ΔepsT were not affected. Instead, ΔepsT had a different swarming behavior from wild SM9913. The swarming of ΔepsT did not have an obvious rapid swarming period, and its rate became much lower than that of wild SM9913 after 35 h incubation. An addition of surfactin or SM9913 EPS on the surface of the swarming plate could rescue the swarming level. These results indicate that the self-secreted EPS is required for the swarming of SM9913. This study widens our understanding of the function of the EPS of benthic bacteria.

  3. Coping with cold: the genome of the versatile marine Antarctica bacterium Pseudoalteromonas haloplanktis TAC125.

    Science.gov (United States)

    Médigue, Claudine; Krin, Evelyne; Pascal, Géraldine; Barbe, Valérie; Bernsel, Andreas; Bertin, Philippe N; Cheung, Frankie; Cruveiller, Stéphane; D'Amico, Salvino; Duilio, Angela; Fang, Gang; Feller, Georges; Ho, Christine; Mangenot, Sophie; Marino, Gennaro; Nilsson, Johan; Parrilli, Ermenegilda; Rocha, Eduardo P C; Rouy, Zoé; Sekowska, Agnieszka; Tutino, Maria Luisa; Vallenet, David; von Heijne, Gunnar; Danchin, Antoine

    2005-10-01

    A considerable fraction of life develops in the sea at temperatures lower than 15 degrees C. Little is known about the adaptive features selected under those conditions. We present the analysis of the genome sequence of the fast growing Antarctica bacterium Pseudoalteromonas haloplanktis TAC125. We find that it copes with the increased solubility of oxygen at low temperature by multiplying dioxygen scavenging while deleting whole pathways producing reactive oxygen species. Dioxygen-consuming lipid desaturases achieve both protection against oxygen and synthesis of lipids making the membrane fluid. A remarkable strategy for avoidance of reactive oxygen species generation is developed by P. haloplanktis, with elimination of the ubiquitous molybdopterin-dependent metabolism. The P. haloplanktis proteome reveals a concerted amino acid usage bias specific to psychrophiles, consistently appearing apt to accommodate asparagine, a residue prone to make proteins age. Adding to its originality, P. haloplanktis further differs from its marine counterparts with recruitment of a plasmid origin of replication for its second chromosome.

  4. Anti-biofilm activity of Pseudoalteromonas flavipulchra SktPp1 against Serratia marcescens SMJ-11

    Science.gov (United States)

    Iqbal, Faiq; Usup, Gires; Ahmad, Asmat

    2015-09-01

    This study aimed to examine the anti-biofilm activity of Pseudoalteromonas flavipulchra SktPp1 crude extract against the biofilm producer, Serratia marcescens. The crude extract of P. flavipulchra SktPp1 was extracted with ethyl acetate. The sub-minimum inhibitory concentration (MIC), 0.1 mg/ml, has been used in this study. The anti-biofilm activity of P. flavipulchra SktPp1 crude extract was assessed against the biofilm of S. marcescens using the crystal violet assay. The growth curve has been used as the indicator of the effect of crude extracts to bacterial growth. The sub-MIC crude extract was tested against two of S. marcescens virulence factors, including the swarming ability and production of prodigiosin using the swarming assay and prodigiosin assay. The growth curves of S. marcescens indicated that the sub-MIC concentration of crude extract did not affect the growth of S. marcescens. The production of prodigiosin was reduced by 44%. The diameter of the swarming area was reduced from 8.7 cm to 0.8 cm. The sub-MIC crude extract inhibits 26.9% of the biofilm production in S. marcescens. This crude extract lost its activity at 50°C and above. In conclusion, crude extract of P. flavipulchra SktPp1 has the ability to inhibit S. marcescens SMJ-11 biofilm formation.

  5. Inhibition of fungal colonization by Pseudoalteromonas tunicata provides a competitive advantage during surface colonization.

    Science.gov (United States)

    Franks, A; Egan, S; Holmström, C; James, S; Lappin-Scott, H; Kjelleberg, S

    2006-09-01

    The marine epiphytic bacterium Pseudoalteromonas tunicata produces a range of extracellular secondary metabolites that inhibit an array of common fouling organisms, including fungi. In this study, we test the hypothesis that the ability to inhibit fungi provides P. tunicata with an advantage during colonization of a surface. Studies on a transposon-generated antifungal-deficient mutant of P. tunicata, FM3, indicated that a long-chain fatty acid-coenzyme A ligase is involved in the production of a broad-range antifungal compound by P. tunicata. Flow cell experiments demonstrated that production of an antifungal compound provided P. tunicata with a competitive advantage against a marine yeast isolate during surface colonization. This compound enabled P. tunicata to disrupt an already established fungal biofilm by decreasing the number of yeast cells attached to the surface by 66% +/- 9%. For in vivo experiments, the wild-type and FM3 strains of P. tunicata were used to inoculate the surface of the green alga Ulva australis. Double-gradient denaturing gradient gel electrophoresis analysis revealed that after 48 h, the wild-type P. tunicata had outcompeted the surface-associated fungal community, whereas the antifungal-deficient mutant had no effect on the fungal community. Our data suggest that P. tunicata is an effective competitor against fungal surface communities in the marine environment.

  6. Morphological and molecular characterization of Sarcocystis arctica-like sarcocysts from the Arctic fox (Vulpes lagopus) from Alaska, USA

    Science.gov (United States)

    Cerqueira-Cézar, Camila K.; Thompson, Peter C.; Verma, Shiv K.; Mowery, Joseph; Calero-Bernal, Rafael; Antunes Murata, Fernando H.; Sinnett, David R.; Van Hemert, Caroline R.; Rosenthal, Benjamin M.; Dubey, Jitender P.

    2017-01-01

    The muscles of herbivores commonly harbor sarcocysts of parasites belonging to species in the genus Sarcocystis, but such muscle parasites are rare in carnivores. Here, we report Sarcocystis arctica-like sarcocysts in muscles of Arctic foxes (Vulpes lagopus) from Alaska, USA, for the first time. The tongues of 56 foxes were examined for Sarcocystis infection using several methods. Sarcocystis bradyzoites were detected in pepsin digests of 13 (23.2%), and sarcocysts were found in histological sections stained with hematoxylin and eosin (HE) of 9 (16.0%). By light microscopy, sarcocysts were up to 4 mm long and up to 245 μm wide. In HE-stained sections, the sarcocyst wall appeared smooth and up to 1.5 μm thick without visible protrusions. By transmission electron microscopy, the sarcocyst wall had a wavy parasitophorous vacuolar membrane (pvm) folded as pleomorphic villar protrusions (vp), sometimes with anastomoses of villar tips. The vp and the ground substance (gs) layer were smooth and without microtubules. The gs was up to 2.0 μm thick. The total width of the wall including vp and the gs was up to 4.0 μm. The vp were up to 3.0 μm long and most closely resembled “type 9c.” All sarcocysts were mature and contained numerous 8.1 × 2.1 μm sized bradyzoites. Molecular characterization (at 18S rDNA, 28S rDNA, ITS-1, and cox1) showed the highest affinity for S. arctica of the Arctic fox (V. lagopus) from Norway. In the present investigation, we provide evidence that sarcocysts are common in tongues of Alaskan Arctic foxes suggesting that these carnivores are serving as intermediate hosts, and we also provide ultrastructure of S. arctica from the Arctic fox for the first time.

  7. Effects of Reducing the Ambient UV-B Radiation in the High Arctic on Salix arctica and Vaccinium uliginosum

    DEFF Research Database (Denmark)

    Albert, Kristian; Ro-Poulsen, Helge; Mikkelsen, Teis Nørgaard

    2005-01-01

    , transmitting ¿ > 400 nm) were used to reduce UV-B radiation and UV-B+A respectively. A UV transparent film (Teflon, transmitting ¿ > 280 nm) and no film were used as controls. Field measurements showed that the plants under Teflon, Mylar and Lexan received app. 91%, 39% and 17% of the ambient UV-B irradiance......Effects of reducing the ambient UV-B radiation on gas exchange and chlorophyll fluores-cence of two dwarf shrub species, Salix arctica and Vaccinium uliginosum, was studied in a high arctic heath in North East Greenland during two growing seasons. Films (Mylar, transmitting ¿ > 320 nm, and Lexan......, respectively. UV radiation decreased the maximal photochemical efficiency (Fv/Fm) and other fast fluorescence transient derived parameters in both species, despite an increased level of leaf flavonoid content. The responses varied in signifi-cance according to species and site. The relation of these effects...

  8. Effects of reducing the ambient UV-B radiation in the high Arctic on Salix arctica and Vaccinium uliginosum

    DEFF Research Database (Denmark)

    Albert, K.R.; Ro-Poulsen, H.; Mikkelsen, Teis Nørgaard

    2005-01-01

    , transmitting λ > 400 nm) were used to reduce UV-B radiation and UV-B+A respectively. A UV transparent film (Teflon, transmitting λ > 280 nm) and no film were used as controls. Field measurements showed that the plants under Teflon, Mylar and Lexan received app. 91%, 39% and 17% of the ambient UV-B irradiance......Effects of reducing the ambient UV-B radiation on gas exchange and chlorophyll fluores-cence of two dwarf shrub species, Salix arctica and Vaccinium uliginosum, was studied in a high arctic heath in North East Greenland during two growing seasons. Films (Mylar, transmitting λ > 320 nm, and Lexan......, respectively. UV radiation decreased the maximal photochemical efficiency (Fv/Fm) and other fast fluorescence transient derived parameters in both species, despite an increased level of leaf flavonoid content. The responses varied in signifi-cance according to species and site. The relation of these effects...

  9. DC-8 being pushed out of the Arena Arctica hangar in Kiruna, Sweden for the second flight of the SAG

    Science.gov (United States)

    2000-01-01

    This photo shows NASA's DC-8 being pushed out of the Arena Arctica hangar in Kiruna, Sweden for the second flight of the SAGE III Ozone Loss and Validation Experiment (SOLVE). One of Dryden's high-flying ER-2 Airborne Science aircraft, a civilian variant of Lockheed's U-2, and another NASA flying laboratory, Dryden's DC-8, were based north of the Arctic Circle in Kiruna, Sweden during the winter of 2000 to study ozone depletion as part of SOLVE. A large hangar built especially for research, 'Arena Arctica' housed the instrumented aircraft and the scientists. Scientists observed unusually low levels of ozone over the Arctic during recent winters, raising concerns that ozone depletion there could become more widespread as in the Antarctic ozone hole. The NASA-sponsored international mission took place between November 1999 and March 2000 and was divided into three phases. The DC-8 was involved in all three phases returning to Dryden between each phase. The ER-2 flew science collection flights between January and March, remaining in Sweden from Jan. 9 through March 16. 'The collaborative campaign will provide an immense new body of information about the Arctic stratosphere,' said program scientist Dr. Michael Kurylo, NASA Headquarters. 'Our understanding of the Earth's ozone will be greatly enhanced by this research.' NASA is using a DC-8 aircraft as a flying science laboratory. The platform aircraft, based at NASA's Dryden Flight Research Center, Edwards, Calif., collects data for many experiments in support of scientific projects serving the world scientific community. Included in this community are NASA, federal, state, academic and foreign investigators. Data gathered by the DC-8 at flight altitude and by remote sensing have been used for scientific studies in archeology, ecology, geography, hydrology, meteorology, oceanography, volcanology, atmospheric chemistry, soil science and biology.

  10. Life-style and genome structure of marine Pseudoalteromonas siphovirus B8b isolated from the northwestern Mediterranean Sea.

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    Elena Lara

    Full Text Available Marine viruses (phages alter bacterial diversity and evolution with impacts on marine biogeochemical cycles, and yet few well-developed model systems limit opportunities for hypothesis testing. Here we isolate phage B8b from the Mediterranean Sea using Pseudoalteromonas sp. QC-44 as a host and characterize it using myriad techniques. Morphologically, phage B8b was classified as a member of the Siphoviridae family. One-step growth analyses showed that this siphovirus had a latent period of 70 min and released 172 new viral particles per cell. Host range analysis against 89 bacterial host strains revealed that phage B8b infected 3 Pseudoalteromonas strains (52 tested, >99.9% 16S rRNA gene nucleotide identity and 1 non-Pseudoaltermonas strain belonging to Alteromonas sp. (37 strains from 6 genera tested, which helps bound the phylogenetic distance possible in a phage-mediated horizontal gene transfer event. The Pseudoalteromonas phage B8b genome size was 42.7 kb, with clear structural and replication modules where the former were delineated leveraging identification of 16 structural genes by virion structural proteomics, only 4 of which had any similarity to known structural proteins. In nature, this phage was common in coastal marine environments in both photic and aphotic layers (found in 26.5% of available viral metagenomes, but not abundant in any sample (average per sample abundance was 0.65% of the reads. Together these data improve our understanding of siphoviruses in nature, and provide foundational information for a new 'rare virosphere' phage-host model system.

  11. Optimization of Collagenase Production by Pseudoalteromonas sp. SJN2 and Application of Collagenases in the Preparation of Antioxidative Hydrolysates

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    Xinghao Yang

    2017-12-01

    Full Text Available Collagenases are the most important group of commercially-produced enzymes. However, even though biological resources are abundant in the sea, very few of these commercially popular enzymes are from marine sources, especially from marine bacteria. We optimized the production of marine collagenases by Pseudoalteromonas sp. SJN2 and investigated the antioxidant activities of the hydrolysates. Media components and culture conditions associated with marine collagenase production by Pseudoalteromonas sp. SJN2 were optimized by statistical methods, namely Plackett–Burman design and response surface methodology (RSM. Furthermore, the marine collagenases produced by Pseudoalteromonas sp. SJN2 were seen to efficiently hydrolyze marine collagens extracted from fish by-products, and remarkable antioxidant capacities of the enzymatic hydrolysates were shown by DPPH radical scavenging and oxygen radical absorbance capacity (ORAC tests. The final optimized fermentation conditions were as follows: soybean powder, 34.23 g·L−1; culture time, 3.72 d; and temperature, 17.32 °C. Under the optimal fermentation conditions, the experimental collagenase yield obtained was 322.58 ± 9.61 U·mL−1, which was in agreement with the predicted yield of 306.68 U·mL−1. Collagen from Spanish mackerel bone, seabream scale and octopus flesh also showed higher DPPH radical scavenging rates and ORAC values after hydrolysis by the collagenase. This study may have implications for the development and use of marine collagenases. Moreover, seafood waste containing beneficial collagen could be used to produce antioxidant peptides by proteolysis.

  12. Effects of Pseudoalteromonas sp. BC228 on digestive enzyme activity and immune response of juvenile sea cucumber ( Apostichopus japonicus)

    Science.gov (United States)

    Ma, Yuexin; Sun, Feixue; Zhang, Congyao; Bao, Pengyun; Cao, Shuqing; Zhang, Meiyan

    2014-12-01

    A marine bacterium, Pseudoalteromonas sp. BC228 was supplemented to feed in a feeding experiment aiming to determine its ability of enhancing the digestive enzyme activity and immune response of juvenile Apostichopus japonicus. Sea cucumber individuals were fed with the diets containing 0 (control), 105, 107 and 109 CFU g-1 diet of BC228 for 45 days. Results showed that intestinal trypsin and lipase activities were significantly enhanced by 107 and 109 CFU g-1 diet of BC228 in comparison with control ( P digestive enzyme activity of juvenile sea cucumber, stimulated its immune response and enhanced its resistance to the infection of V. splendidus.

  13. Failure of two consecutive annual treatments with ivermectin to eradicate the reindeer parasites (Hypoderma tarandi, Cephenemyia trompe and Linguatula arctica) from an island in northern Norway

    OpenAIRE

    Nilssen, Arne C.; Willy Hemmingsen; Haugerud, Rolf E.

    2002-01-01

    The highly efficient endectocide ivermectin is used to reduce the burden of parasites in many semidomestic reindeer herds in northern Fennoscandia. In the autumn of 1995 and 1996 all reindeer on the island of Silda (42 km2) were treated with ivermectin in an attempt to eradicate the warble fly (Hypoderma (=Oedemagena) tarandi (L.)), the nose bot fly (Cephenemyia trompe (Modeer)) (Diptera: Oestridae) and the sinus worm (Linguatula arctica Riley, Haugerud and Nilssen) (Pentastomida: Linguatulid...

  14. Liquid Chromatography-Mass Spectrometry-Based Rapid Secondary-Metabolite Profiling of Marine Pseudoalteromonas sp. M2

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    Woo Jung Kim

    2016-01-01

    Full Text Available The ocean is a rich resource of flora, fauna, and food. A wild-type bacterial strain showing confluent growth on marine agar with antibacterial activity was isolated from marine water, identified using 16S rDNA sequence analysis as Pseudoalteromonas sp., and designated as strain M2. This strain was found to produce various secondary metabolites including quinolone alkaloids. Using high-resolution mass spectrometry (MS and nuclear magnetic resonance (NMR analysis, we identified nine secondary metabolites of 4-hydroxy-2-alkylquinoline (pseudane-III, IV, V, VI, VII, VIII, IX, X, and XI. Additionally, this strain produced two novel, closely related compounds, 2-isopentylqunoline-4-one and 2-(2,3-dimetylbutylqunoline-4-(1H-one, which have not been previously reported from marine bacteria. From the metabolites produced by Pseudoalteromonas sp. M2, 2-(2,3-dimethylbutylquinolin-4-one, pseudane-VI, and pseudane-VII inhibited melanin synthesis in Melan-A cells by 23.0%, 28.2%, and 42.7%, respectively, wherein pseudane-VII showed the highest inhibition at 8 µg/mL. The results of this study suggest that liquid chromatography (LC-MS/MS-based metabolite screening effectively improves the efficiency of novel metabolite discovery. Additionally, these compounds are promising candidates for further bioactivity development.

  15. Draft Genome Sequence of Pseudoalteromonas sp. Strain XI10 Isolated from the Brine-Seawater Interface of Erba Deep in the Red Sea

    KAUST Repository

    Zhang, Guishan

    2016-03-10

    Pseudoalteromonas sp. strain XI10 was isolated from the brine-seawater interface of Erba Deep in the Red Sea, Saudi Arabia. Here, we present the draft genome sequence of strain XI10, a gammaproteobacterium that synthesizes polysaccharides for biofilm formation when grown in liquid culture.

  16. Fed-batch process for the psychrotolerant marine bacterium Pseudoalteromonas haloplanktis

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    Lalk Michael

    2010-09-01

    Full Text Available Abstract Background Pseudoalteromonas haloplanktis is a cold-adapted γ-proteobacterium isolated from Antarctic sea ice. It is characterized by remarkably high growth rates at low temperatures. P. haloplanktis is one of the model organisms of cold-adapted bacteria and has been suggested as an alternative host for the soluble overproduction of heterologous proteins which tend to form inclusion bodies in established expression hosts. Despite the progress in establishing P. haloplanktis as an alternative expression host the cell densities obtained with this organism, which is unable to use glucose as a carbon source, are still low. Here we present the first fed-batch cultivation strategy for this auspicious alternative expression host. Results The key for the fed-batch cultivation of P. haloplanktis was the replacement of peptone by casamino acids, which have a much higher solubility and allow a better growth control. In contrast to the peptone medium, on which P. haloplanktis showed different growth phases, on a casamino acids-containing, phosphate-buffered medium P. haloplanktis grew exponentially with a constant growth rate until the stationary phase. A fed-batch process was established by feeding of casamino acids with a constant rate resulting in a cell dry weight of about 11 g l-1 (OD540 = 28 which is a twofold increase of the highest densities which have been obtained with P. haloplanktis so far and an eightfold increase of the density obtained in standard shake flask cultures. The cell density was limited in the fed-batch cultivation by the relatively low solubility of casamino acids (about 100 g l-1, which was proven by pulse addition of casamino acid powder which increased the cell density to about 20 g l-1 (OD540 = 55. Conclusion The growth of P. haloplanktis to higher cell densities on complex medium is possible. A first fed-batch fermentation strategy could be established which is feasible to be used in lab-scale or for industrial

  17. Pseudoalteromonas spp. serve as initial bacterial attractants in mesocosms of coastal waters but have subsequent antifouling capacity in mesocosms and when embedded in paint.

    Science.gov (United States)

    Bernbom, Nete; Ng, Yoke Yin; Olsen, Stefan Møller; Gram, Lone

    2013-11-01

    The purpose of the present study was to determine if the monoculture antifouling effect of several pigmented pseudoalteromonads was retained in in vitro mesocosm systems using natural coastal seawater and when the bacteria were embedded in paint used on surfaces submerged in coastal waters. Pseudoalteromonas piscicida survived on a steel surface and retained antifouling activity for at least 53 days in sterile seawater, whereas P. tunicata survived and had antifouling activity for only 1 week. However, during the first week, all Pseudoalteromonas strains facilitated rather than prevented bacterial attachment when used to coat stainless steel surfaces and submerged in mesocosms with natural seawater. The bacterial density on surfaces coated with sterile growth medium was 10(5) cells/cm(2) after 7 days, whereas counts on surfaces precoated with Pseudoalteromonas were significantly higher, at 10(6) to 10(8) cells/cm(2). However, after 53 days, seven of eight Pseudoalteromonas strains had reduced total bacterial adhesion compared to the control. P. piscicida, P. antarctica, and P. ulvae remained on the surface, at levels similar to those in the initial coating, whereas P. tunicata could not be detected. Larger fouling organisms were observed on all plates precoated with Pseudoalteromonas; however, plates coated only with sterile growth medium were dominated by a bacterial biofilm. Suspensions of a P. piscicida strain and a P. tunicata strain were incorporated into ship paints (Hempasil x3 87500 and Hempasil 77500) used on plates that were placed at the Hempel A/S test site in Jyllinge Harbor. For the first 4 months, no differences were observed between control plates and treated plates, but after 5 to 6 months, the control plates were more fouled than the plates with pseudoalteromonad-based paint. Our study demonstrates that no single laboratory assay can predict antifouling effects and that a combination of laboratory and real-life methods must be used to determine

  18. Neisseria arctica sp. nov. isolated from nonviable eggs of greater white-fronted geese (Anser albifrons) in Arctic Alaska

    Science.gov (United States)

    Hansen, Cristina M.; Himschoot, Elizabeth; Hare, Rebekah F.; Meixell, Brandt; Van Hemert, Caroline R.; Hueffer, Karsten

    2017-01-01

    During the summers of 2013 and 2014, isolates of a novel Gram-negative coccus in the Neisseria genus were obtained from the contents of nonviable greater white-fronted goose (Anser albifrons) eggs on the Arctic Coastal Plain of Alaska. We used a polyphasic approach to determine whether these isolates represent a novel species. 16S rRNA gene sequences, 23S rRNA gene sequences, and chaperonin 60 gene sequences suggested that these Alaskan isolates are members of a distinct species that is most closely related to Neisseria canis, N. animaloris, and N. shayeganii. Analysis of the rplF gene additionally showed that our isolates are unique and most closely related to N. weaveri. Average nucleotide identity of the whole genome sequence of our type strain was between 71.5% and 74.6% compared to close relatives, further supporting designation as a novel species. Fatty acid methyl ester analysis showed a predominance of C14:0, C16:0, and C16:1ω7c fatty acids. Finally, biochemical characteristics distinguished our isolates from other Neisseria species. The name Neisseria arctica (type strain KH1503T = ATCC TSD-57T = DSM 103136T) is proposed.

  19. Development and application of the mollusc Arctica islandica as a paleoceanographic tool for the North Atlantic Ocean

    Energy Technology Data Exchange (ETDEWEB)

    Weidman, C.R.

    1995-09-01

    Until now there has been no tool comparable to corals for reconstructing long term high-resolution geochemical time-series for the colder, higher-latitude oceans. In this thesis, the long-lived (+100 years) boreal mollusc (Bivalvia) Arctica islandica is shown to be practical for this purpose in the northern North Atlantic Ocean. The evidence, compiled here, demonstrates that the carbonate shell of this species faithfully records the ambient dissolved inorganic carbon`s (DIC) radiocarbon ({Delta}{sup 14}C) concentration and accurately reflects the ambient temperature in its stable oxygen isotope ({delta}{sup 18}O) composition. However, the stable carbon isotope ({delta}{sup 13}C) composition of the A. islandica shell likely is not a good recorder of ambient DIC {delta}{sup 13}C, and likely responds to physiological controls. Four {Delta}{sup 14}C time histories are reconstructed from the annual bands of A. islandica shells for the higher-latitudes of the northern North Atlantic Ocean (from 41{degree}N to 70{degree}N).

  20. Stereochemical course of hydrolytic reaction catalyzed by alpha-galactosidase from cold adaptable marine bacterium of genus Pseudoalteromonas

    Science.gov (United States)

    Bakunina, Irina; Balabanova, Larissa; Golotin, Vasiliy; Slepchenko, Lyubov; Isakov, Vladimir; Rasskazov, Valeriy

    2014-10-01

    The recombinant α-galactosidase of the marine bacterium (α-PsGal) was synthesized with the use of the plasmid 40Gal, consisting of plasmid pET-40b (+) (Novagen) and the gene corresponding to the open reading frame of the mature α-galactosidase of marine bacterium Pseudoalteromonas sp. KMM 701, transformed into the E. coli Rosetta(DE3) cells. In order to understand the mechanism of action, the stereochemistry of hydrolysis of 4-nitrophenyl α-D-galactopyranoside (4-NPGP) by α-PsGal was measured by 1H NMR spectroscopy. The kinetics of formation of α- and β-anomer of galactose showed that α-anomer initially formed and accumulated, and then an appreciable amount of β-anomer appeared as a result of mutarotation. The data clearly show that the enzymatic hydrolysis of 4-NPGP proceeds with the retention of anomeric configuration, probably, due to a double displacement mechanism of reaction.

  1. Stereochemical course of hydrolytic reaction catalyzed by alpha-galactosidase from cold adaptable marine bacterium of genus Pseudoalteromonas

    Directory of Open Access Journals (Sweden)

    Irina Yu Bakunina

    2014-10-01

    Full Text Available The recombinant α-galactosidase of the marine bacterium (α-PsGal was synthesized with the use of the plasmid 40Gal, consisting of plasmid pET-40b (+ (Novagen and the gene corresponding to the open reading frame of the mature α-galactosidase of marine bacterium Pseudoalteromonas sp. KMM 701, transformed into the E. coli Rosetta(DE3 cells. In order to understand the mechanism of action, the stereochemistry of hydrolysis of 4-nitrophenyl α-D-galactopyranoside (4-NPGP by α-PsGal was measured by 1H NMR spectroscopy. The kinetics of formation of α- and β-anomer of galactose showed that α-anomer initially formed and accumulated, and then an appreciable amount of β-anomer appeared as a result of mutarotation. The data clearly show that the enzymatic hydrolysis of 4-NPGP proceeds with the retention of anomeric configuration, probably, due to a double displacement mechanism of reaction.

  2. Comparative genomics reveals a deep-sea sediment-adapted life style of Pseudoalteromonas sp. SM9913.

    Science.gov (United States)

    Qin, Qi-Long; Li, Yang; Zhang, Yan-Jiao; Zhou, Zhe-Min; Zhang, Wei-Xin; Chen, Xiu-Lan; Zhang, Xi-Ying; Zhou, Bai-Cheng; Wang, Lei; Zhang, Yu-Zhong

    2011-02-01

    Deep-sea sediment is one of the most important microbial-driven ecosystems, yet it is not well characterized. Genome sequence analyses of deep-sea sedimentary bacteria would shed light on the understanding of this ecosystem. In this study, the complete genome of deep-sea sedimentary bacterium Pseudoalteromonas sp. SM9913 (SM9913) is described and compared with that of the closely related Antarctic surface sea-water ecotype Pseudoalteromonas haloplanktis TAC125 (TAC125). SM9913 has fewer dioxygenase genes than TAC125, indicating a possible sensitivity to reactive oxygen species. Accordingly, experimental results showed that SM9913 was less tolerant of H(2)O(2) than TAC125. SM9913 has gene clusters related to both polar and lateral flagella biosynthesis. Lateral flagella, which are usually present in deep-sea bacteria and absent in the related surface bacteria, are important for the survival of SM9913 in deep-sea environments. With these two flagellar systems, SM9913 can swim in sea water and swarm on the sediment particle surface, favoring the acquisition of nutrients from particulate organic matter and reflecting the particle-associated alternative lifestyle of SM9913 in the deep sea. A total of 12 genomic islands were identified in the genome of SM9913 that may confer specific features unique to SM9913 and absent from TAC125, such as drug and heavy metal resistance. Many signal transduction genes and a glycogen production operon were also present in the SM9913 genome, which may help SM9913 respond to food pulses and store carbon and energy in a deep-sea environment.

  3. Pseudane-VII Isolated from Pseudoalteromonas sp. M2 Ameliorates LPS-Induced Inflammatory Response In Vitro and In Vivo

    Directory of Open Access Journals (Sweden)

    Mi Eun Kim

    2017-11-01

    Full Text Available The ocean is a rich resource of flora, fauna, food, and biological products. We found a wild-type bacterial strain, Pseudoalteromonas sp. M2, from marine water and isolated various secondary metabolites. Pseudane-VII is a compound isolated from the Pseudoalteromonas sp. M2 metabolite that possesses anti-melanogenic activity. Inflammation is a response of the innate immune system to microbial infections. Macrophages have a critical role in fighting microbial infections and inflammation. Recent studies reported that various compounds derived from natural products can regulate immune responses including inflammation. However, the anti-inflammatory effects and mechanism of pseudane-VII in macrophages are still unknown. In this study, we investigated the anti-inflammatory effects of pseudane-VII. In present study, lipopolysaccharide (LPS-induced nitric oxide (NO production was significantly decreased by pseudane-VII treatment at 6 μM. Moreover, pseudane-VII treatment dose-dependently reduced mRNA levels of pro-inflammatory cytokines including inos, cox-2, il-1β, tnf-α, and il-6 in LPS-stimulated macrophages. Pseudane-VII also diminished iNOS protein levels and IL-1β secretion. In addition, Pseudane-VII elicited anti-inflammatory effects by inhibiting ERK, JNK, p38, and nuclear factor (NF-κB-p65 phosphorylation. Consistently, pseudane-VII was also shown to inhibit the LPS-stimulated release of IL-1β and expression of iNOS in mice. These results suggest that pseudane-VII exerted anti-inflammatory effects on LPS-stimulated macrophage activation via inhibition of ERK, JNK, p38 MAPK phosphorylation, and pro-inflammatory gene expression. These findings may provide new approaches in the effort to develop anti-inflammatory therapeutics.

  4. Gene expression and physiological changes of different populations of the long-lived bivalve Arctica islandica under low oxygen conditions.

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    Eva E R Philipp

    Full Text Available The bivalve Arctica islandica is extremely long lived (>400 years and can tolerate long periods of hypoxia and anoxia. European populations differ in maximum life spans (MLSP from 40 years in the Baltic to >400 years around Iceland. Characteristic behavior of A. islandica involves phases of metabolic rate depression (MRD during which the animals burry into the sediment for several days. During these phases the shell water oxygen concentrations reaches hypoxic to anoxic levels, which possibly support the long life span of some populations. We investigated gene regulation in A. islandica from a long-lived (MLSP 150 years German Bight population and the short-lived Baltic Sea population, experimentally exposed to different oxygen levels. A new A. islandica transcriptome enabled the identification of genes important during hypoxia/anoxia events and, more generally, gene mining for putative stress response and (anti- aging genes. Expression changes of a antioxidant defense: Catalase, Glutathione peroxidase, manganese and copper-zinc Superoxide dismutase; b oxygen sensing and general stress response: Hypoxia inducible factor alpha, Prolyl hydroxylase and Heat-shock protein 70; and c anaerobic capacity: Malate dehydrogenase and Octopine dehydrogenase, related transcripts were investigated. Exposed to low oxygen, German Bight individuals suppressed transcription of all investigated genes, whereas Baltic Sea bivalves enhanced gene transcription under anoxic incubation (0 kPa and, further, decreased these transcription levels again during 6 h of re-oxygenation. Hypoxic and anoxic exposure and subsequent re-oxygenation in Baltic Sea animals did not lead to increased protein oxidation or induction of apoptosis, emphasizing considerable hypoxia/re-oxygenation tolerance in this species. The data suggest that the energy saving effect of MRD may not be an attribute of Baltic Sea A. islandica chronically exposed to high environmental variability (oxygenation

  5. Extracellular proteases from the Antarctic marine Pseudoalteromonas sp. P96-47 strain Proteasas extracelulares de la cepa marina antártica Pseudoalteromonas sp. P96-47

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    S.C. Vázquez

    2008-03-01

    Full Text Available The extracellular protease-production capacity of 33 bacterial isolates taken from marine biotopes in King George Island, Antarctica, was evaluated in liquid cultures. The P96-47 isolate was selected due to its high production capacity and was identified as Pseudoalteromonas sp. The optimal growth temperature was 20 °C and the optimal for protease production was 15 °C. Proteases were purified from culture supernatants, developing a multiple-band profile in zymograms. They were classified as neutral metalloproteases and worked optimally at 45 °C with an Eact of 47 kJ/ mol. Their stability was higher at neutral pH, retaining more than 80% of activity at pH 6-10 after 3 h incubation at 4 °C. After 90 min incubation at 40 and 50 °C, the percentages of residual activities were 78% and 44%. These results contribute to the basic knowledge of Antarctic marine proteases and also help evaluate the probable industrial applications of P96-47 proteases.La capacidad productora de proteasas extracelulares de 33 aislamientos bacterianos tomados de biotopos marinos en la Isla Rey Jorge, Antártida, fue evaluada en cultivo líquido. El aislamiento P96-47 fue seleccionado debido a su alta capacidad productora y fue identificado como Pseudoalteromonas sp. La temperatura óptima de crecimiento fue de 20 °C y la de producción de 15 °C. Las proteasas fueron purificadas a partir del sobrenadante de cultivo, y en los zimogramas desarrollaron un perfil de múltiples bandas. Estas proteasas fueron clasificadas como metaloproteasas neutras y se observó que trabajan óptimamente a 45 °C, con una Eact de 47 kJ/ mol. Su estabilidad fue superior a pH neutro y retuvieron más del 80% de su actividad a pH 6-10 después de 3 h de incubación a 4 °C. Luego de 90 min de incubación a 40 y 50 °C, las actividades residuales fueron 78% y 44%, respectivamente. Los resultados que se presentan en este trabajo contribuyen al conocimiento básico de las proteasas marinas ant

  6. Environmental controls on the boron and strontium isotopic composition of aragonite shell material of cultured Arctica islandica

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    Y.-W. Liu

    2015-06-01

    Full Text Available Ocean acidification, the decrease in ocean pH associated with increasing atmospheric CO2, is likely to impact marine organisms, particularly those that produce carbonate skeletons or shells. Therefore, it is important to investigate how environmental factors (seawater pH, temperature and salinity influence the chemical compositions in biogenic carbonates. In this study we report the first high-resolution strontium (87Sr / 86Sr and δ88 / 86Sr and boron (δ11B isotopic values in the aragonite shell of cultured Arctica islandica (A. islandica. The 87Sr / 86Sr ratios from both tank water and shell samples show ratios nearly identical to the open ocean, which suggests that the shell material reflects ambient ocean chemistry without terrestrial influence. The 84Sr–87Sr double-spike-resolved shell δ88 / 86Sr and Sr concentration data show no resolvable change throughout the culture period and reflect no theoretical kinetic mass fractionation throughout the experiment despite a temperature change of more than 15 °C. The δ11B records from the experiment show at least a 5‰ increase through the 29-week culture season (January 2010–August 2010, with low values from the beginning to week 19 and higher values thereafter. The larger range in δ11B in this experiment compared to predictions based on other carbonate organisms (2–3‰ suggests that a species-specific fractionation factor may be required. A significant correlation between the ΔpH (pHshell − pHsw and seawater pH (pHsw was observed (R2 = 0.35, where the pHshell is the calcification pH of the shell calculated from boron isotopic composition. This negative correlation suggests that A. islandica partly regulates the pH of the extrapallial fluid. However, this proposed mechanism only explains approximately 35% of the variance in the δ11B data. Instead, a rapid rise in δ11B of the shell material after week 19, during the summer, suggests that the boron uptake changes when a thermal

  7. PhAP protease from Pseudoalteromonas haloplanktis TAC125: Gene cloning, recombinant production in E. coli and enzyme characterization

    Science.gov (United States)

    de Pascale, D.; Giuliani, M.; De Santi, C.; Bergamasco, N.; Amoresano, A.; Carpentieri, A.; Parrilli, E.; Tutino, M. L.

    2010-08-01

    Cold-adapted proteases have been found to be the dominant activity throughout the cold marine environment, indicating their importance in bacterial acquisition of nitrogen-rich complex organic compounds. However, few extracellular proteases from marine organisms have been characterized so far, and the mechanisms that enable their activity in situ are still largely unknown. Aside from their ecological importance and use as model enzyme for structure/function investigations, cold-active proteolytic enzymes offer great potential for biotechnological applications. Our studies on cold adapted proteases were performed on exo-enzyme produced by the Antarctic marine bacterium Pseudoalteromonas haloplanktis TAC125. By applying a proteomic approach, we identified several proteolytic activities from its culture supernatant. PhAP protease was selected for further investigations. The encoding gene was cloned and the protein was recombinantly produced in E. coli cells. The homogeneous product was biochemically characterised and it turned out that the enzyme is a Zn-dependent aminopeptidase, with an activity dependence from assay temperature typical of psychrophilic enzymes.

  8. Analysis of extracellular alginate lyase and its gene from a marine bacterial strain, Pseudoalteromonas atlantica AR06.

    Science.gov (United States)

    Matsushima, Ryoji; Danno, Hiroko; Uchida, Motoharu; Ishihara, Kenji; Suzuki, Toshiyuki; Kaneniwa, Masaki; Ohtsubo, Yoshiyuki; Nagata, Yuji; Tsuda, Masataka

    2010-03-01

    Pseudoalteromonas atlantica AR06 is a marine bacterial strain that can utilize alginate as a sole source of carbon and energy. The extracellular protein fraction prepared from the AR06 cultivation media exhibited alginate lyase activity to depolymerize the alginate molecules having homopolymeric and heteropolymeric forms of mannuronate and guluronate so as to mainly convert into the dimer to tetramer. A DNA fragment encoding a portion of alginate lyase was amplified from AR06 genomic DNA by PCR using a set of degenerated primers, and then the whole alginate lyase gene, named alyA, and its flanking regions were obtained from a cosmid library of AR06 genomic DNA. The alyA mutant of AR06 showed (1) the loss of alginate depolymerization activity on alginate agar plate and (2) significant growth defects in alginate minimal medium; these defects were complemented by the introduction of the alyA gene. Furthermore, zymography and biochemical analyses revealed that three extracellular protein bands of AR06 had alginate lyase activities and that all three protein bands were derived from the nascent alyA gene product. These results clearly indicated that the alyA gene greatly contributes to the assimilation of alginate in AR06. The transcription of the alyA gene was induced by the presence of alginate in minimal medium, but its obvious induction was not observed in rich medium even in the presence of alginate.

  9. Adhesion of Bacillus subtilis and Pseudoalteromonas lipolytica to steel in a seawater environment and their effects on corrosion.

    Science.gov (United States)

    Guo, Zhangwei; Liu, Tao; Cheng, Y Frank; Guo, Na; Yin, Yansheng

    2017-09-01

    In a marine environment, Bacillus subtilis and Pseudoalteromonas lipolytica are commonly found in the biofilms adherent to low-alloy engineering steel, and they have distinct effects on corrosion. In the present work, this phenomenon was investigated through the study of various materials characterization methods, electrochemical techniques, and contact angle measurements. It was found that the surface film formed on the steel in the presence of B. subtilis was compact, uniform, free of cracks, and hydrophobic. However, the film formed in the presence of P. lipolytica was loose, rough, heterogeneous, and hydrophilic. The main components of the films formed in the presence of B. subtilis and P. lipolytica were polysaccharides/TasA amyloid fibers and proteins/carboxylic acid, respectively. The composition, structure, and properties of the surface films formed on the steel were associated with different effects on corrosion. The presence of B. subtilis enhances the steel's resistance to corrosion, whereas corrosion was increased by the presence of P. lipolytica. In short, the compact and hydrophobic biofilm of B. subtilis appears to inhibit the corrosion of steel, while the loose, hydrophilic film of P. lipolytica tends to induce pitting corrosion. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Cloning, Expression, Purification, and Characterization of Glutaredoxin from Antarctic Sea-Ice Bacterium Pseudoalteromonas sp. AN178

    Directory of Open Access Journals (Sweden)

    Quanfu Wang

    2014-01-01

    Full Text Available Glutaredoxins (Grxs are small ubiquitous redox enzymes that catalyze glutathione-dependent reactions to reduce protein disulfide. In this study, a full-length Grx gene (PsGrx with 270 nucleotides was isolated from Antarctic sea-ice bacterium Pseudoalteromonas sp. AN178. It encoded deduced 89 amino acid residues with the molecular weight 9.8 kDa. Sequence analysis of the amino acid sequence revealed the catalytic motif CPYC. Recombinant PsGrx (rPsGrx stably expressed in E. coli BL21 was purified to apparent homogeneity by Ni-affinity chromatography. rPsGrx exhibited optimal activity at 30°C and pH 8.0 and showed 25.5% of the activity at 0°C. It retained 65.0% of activity after incubation at 40°C for 20 min and still exhibited 37.0% activity in 1.0 M NaCl. These results indicated that rPsGrx was a typical cold active protein with low thermostability.

  11. Dissolved inorganic carbon, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the STENA ARCTICA in the South Atlantic Ocean from 1989-02-14 to 1989-03-17 (NODC Accession 0113893)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0113893 includes chemical, discrete sample, physical and profile data collected from STENA ARCTICA in the South Atlantic Ocean from 1989-02-14 to...

  12. Partial pressure (or fugacity) of carbon dioxide, temperature, and other variables collected from surface underway observations using carbon dioxide gas analyzer, shower head equilibrator and other instruments from SOOP M/V Nuka Arctica lines in the North Atlantic Ocean from 2008-01-08 to 2009-01-07 (NCEI Accession 0162251)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0162251 includes Surface underway, chemical, meteorological and physical data collected from SOOP M/V Nuka Arctica lines in the North Atlantic Ocean...

  13. Partial pressure (or fugacity) of carbon dioxide and other variables collected from Surface underway observations using Carbon dioxide (CO2) gas analyzer, Shower head chamber equilibrator for autonomous carbon dioxide (CO2) measurement and other instruments from NUKA ARCTICA in the Davis Strait, Kattegat and others from 2007-04-27 to 2008-01-05 (NCEI Accession 0144288)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0144288 includes Surface underway data collected from NUKA ARCTICA in the Davis Strait, Kattegat, The Sound, Great Belt, Little Belt, North Atlantic...

  14. Effects of ambient versus reduced UV-B radiation on high arctic Salix arctica assessed by measurements and calculations of chlorophyll-a fluorescence parameters from fluorescence transients

    DEFF Research Database (Denmark)

    Albert, Kristian Rost

    2005-01-01

    A UV-B exclusion-experiment was conducted in the high arctic Zackenberg, NE Greenland, in which Salix arctica leaves during most of the growing season were fixed perpendicular to the solar zenith angle, thereby receiving maximal solar radiation. Covered with Teflon and Mylar foil, the leaves...... of evaluating the relative importance of UV-B of donor and acceptor side capacity in Photosystem II. In conclusion, the experimental set-up and non-invasive measurements proved to be a sensitive method to screen for effects of UV-B stress....... received approximately 90 and 40% of the ambient UV-B irradiance, respectively. The effects were examined through recordings of chlorophyll a fluorescence transients, determination of biomass and analysis of total carbon and nitrogen content and amount of soluble flavonoids in the leaves. The processing...

  15. Failure of two consecutive annual treatments with ivermectin to eradicate the reindeer parasites (Hypoderma tarandi, Cephenemyia trompe and Linguatula arctica from an island in northern Norway

    Directory of Open Access Journals (Sweden)

    Arne C. Nilssen

    2002-03-01

    Full Text Available The highly efficient endectocide ivermectin is used to reduce the burden of parasites in many semidomestic reindeer herds in northern Fennoscandia. In the autumn of 1995 and 1996 all reindeer on the island of Silda (42 km2 were treated with ivermectin in an attempt to eradicate the warble fly (Hypoderma (=Oedemagena tarandi (L., the nose bot fly (Cephenemyia trompe (Modeer (Diptera: Oestridae and the sinus worm (Linguatula arctica Riley, Haugerud and Nilssen (Pentastomida: Linguatulidae. Silda is situated 2-3 km off the mainland of Finnmark, northern Norway, and supports about 475 reindeer in summer. A year after the first treatment, the mean abundance of H. tarandi was reduced from 3.5 to 0.6, but a year after the second treatment the mean abundance unexpectedly had increased to 4.5. After one year without treatment, the mean abundance and prevalence of the three target parasites were at the same level, or higher, than pre-treatment levels. The main hypothesis for the failure to eliminate the parasites is that gravid H. tarandi and C. trompe females originating from untreated reindeer in adjacent mainland areas dispersed to the island during the warm summer of 1997 (possibly also in 1998. As these oestrids are strong flyers, it may not be too difficult for them to cross >2-3 km of oceanic waters. There are no good explanations for the failure to eradicate L. arctica, but the results indicate that there may be elements in its life cycle that are unknown. The conclusion of the study is that it may be difficult or impossible to eradicate these parasites permanently, even locally such as on islands unless adjacent areas on the mainland are also cleared.

  16. Behavioral responses of Arctica islandica (Bivalvia: Arcticidae) to simulated leakages of carbon dioxide from sub-sea geological storage

    Energy Technology Data Exchange (ETDEWEB)

    Bamber, Shaw D., E-mail: shaw.bamber@iris.no; Westerlund, Stig, E-mail: sw@iris.no

    2016-11-15

    Highlights: • Valve pumping activity in A. islandica significantly increased at pH 6.2 seawater. • Changes in valve movements were not related to attempted burrowing activities. • Valve activity returned to control levels after 5 days of continuous exposure. • A. islandica tolerate pH reductions likely to follow leakage of sub-sea stored CO{sub 2}. - Abstract: Sub-sea geological storage of carbon dioxide (CO{sub 2}) provides a viable option for the Carbon Capture and Storage (CCS) approach for reducing atmospheric emissions of this greenhouse gas. Although generally considered to offer a low risk of major leakage, it remains relevant to establish the possible consequences for marine organisms that live in or on sediments overlying these storage areas if such an event may occur. The present study has used a series of laboratory exposures and behavioral bioassays to establish the sensitivity of Arctica islandica to simulated leakages of CO{sub 2}. This long-lived bivalve mollusc is widely distributed throughout the North Sea, an area where geological storage is currently taking place and where there are plans to expand this operation significantly. A recently published model has predicted a maximum drop of 1.9 pH units in seawater at the point source of a substantial escape of CO{sub 2} from sub-sea geological storage in this region. Valve movements of A. islandica exposed to reduced pH seawater were recorded continuously using Hall effect proximity sensors. Valve movement regulation is important for optimising the flow of water over the gills, which supplies food and facilitates respiration. A stepwise reduction in seawater pH showed an initial increase in both the rate and extent of valve movements in the majority of individuals tested when pH fell to 6.2 units. Exposing A. islandica to pH 6.2 seawater continuously for seven days resulted in a clear increase in valve movements during the first 40 h of exposure, followed by a gradual reduction in activity

  17. Pseudoalteromonas piratica strain OCN003 is a coral pathogen that causes a switch from chronic to acute Montipora white syndrome in Montipora capitata.

    Directory of Open Access Journals (Sweden)

    Silvia Beurmann

    Full Text Available Reports of mass coral mortality from disease have increased over the last two decades. Montipora white syndrome (MWS is a tissue loss disease that has negatively impacted populations of the coral Montipora capitata in Kāne'ohe Bay, Hawai'i. Two types of MWS have been documented; a progressive disease termed chronic MWS (cMWS, that can be caused by Vibrio owensii strain OCN002, and a comparatively faster disease termed acute MWS (aMWS, that can be caused by Vibrio coralliilyticus strain OCN008. M. capitata colonies exhibiting cMWS can spontaneously switch to aMWS in the field. In this study, a novel Pseudoalteromonas species, P. piratica strain OCN003, fulfilled Koch's postulates of disease causation as another etiological agent of aMWS. Additionally, OCN003 induced a switch from cMWS to aMWS on M. capitata in laboratory infection trials. A comparison of OCN003 and Vibrio coralliilyticus strain OCN008, showed that OCN003 was more effective at inducing the cMWS to aMWS switch in M. capitata than OCN008. This study is the first to demonstrate that similar disease signs on one coral species (aMWS on M. capitata can be caused by multiple pathogens, and describes the first Pseudoalteromonas species that infects coral.

  18. Analysis of the Pseudoalteromonas tunicata genome reveals properties of a surface-associated life style in the marine environment.

    Directory of Open Access Journals (Sweden)

    Torsten Thomas

    Full Text Available BACKGROUND: Colonisation of sessile eukaryotic host surfaces (e.g. invertebrates and seaweeds by bacteria is common in the marine environment and is expected to create significant inter-species competition and other interactions. The bacterium Pseudoalteromonas tunicata is a successful competitor on marine surfaces owing primarily to its ability to produce a number of inhibitory molecules. As such P. tunicata has become a model organism for the studies into processes of surface colonisation and eukaryotic host-bacteria interactions. METHODOLOGY/PRINCIPAL FINDINGS: To gain a broader understanding into the adaptation to a surface-associated life-style, we have sequenced and analysed the genome of P. tunicata and compared it to the genomes of closely related strains. We found that the P. tunicata genome contains several genes and gene clusters that are involved in the production of inhibitory compounds against surface competitors and secondary colonisers. Features of P. tunicata's oxidative stress response, iron scavenging and nutrient acquisition show that the organism is well adapted to high-density communities on surfaces. Variation of the P. tunicata genome is suggested by several landmarks of genetic rearrangements and mobile genetic elements (e.g. transposons, CRISPRs, phage. Surface attachment is likely to be mediated by curli, novel pili, a number of extracellular polymers and potentially other unexpected cell surface proteins. The P. tunicata genome also shows a utilisation pattern of extracellular polymers that would avoid a degradation of its recognised hosts, while potentially causing detrimental effects on other host types. In addition, the prevalence of recognised virulence genes suggests that P. tunicata has the potential for pathogenic interactions. CONCLUSIONS/SIGNIFICANCE: The genome analysis has revealed several physiological features that would provide P. tunciata with competitive advantage against other members of the surface

  19. ER-2 #809 and DC-8 in Arena Arctica hangar in Kiruna, Sweden prior to the SAGE III Ozone Loss and Va

    Science.gov (United States)

    2000-01-01

    NASA ER-2 # 809 and its DC-8 shown in Arena Arctica before the SAGE III Ozone Loss and Validation Experiment (SOLVE). The two airborne science platforms were based north of the Arctic Circle in Kiruna, Sweden, during the winter of 2000 to study ozone depletion as part of SOLVE. A large hangar built especially for research, 'Arena Arctica' housed the instrumented aircraft and the scientists. Scientists have observed unusually low levels of ozone over the Arctic during recent winters, raising concerns that ozone depletion there could become more widespread as in the Antarctic ozone hole. The NASA-sponsored international mission took place between November 1999 and March 2000 and was divided into three phases. The DC-8 was involved in all three phases returning to Dryden between each phase. The ER-2 flew sample collection flights between January and March, remaining in Sweden from Jan. 9 through March 16. 'The collaborative campaign will provide an immense new body of information about the Arctic stratosphere,' said program scientist Dr. Michael Kurylo, NASA Headquarters. 'Our understanding of the Earth's ozone will be greatly enhanced by this research.' ER-2s bearing tail numbers 806 and 809 are used as airborne science platforms by NASA's Dryden Flight Research Center. The aircraft are platforms for a variety of high-altitude science missions flown over various parts of the world. They are also used for earth science and atmospheric sensor research and development, satellite calibration and data validation. The ER-2s are capable of carrying a maximum payload of 2,600 pounds of experiments in a nose bay, the main equipment bay behind the cockpit, two wing-mounted superpods and small underbody and trailing edges. Most ER-2 missions last about six hours with ranges of about 2,200 nautical miles. The aircraft typically fly at altitudes above 65,000 feet. On November 19, 1998, an ER-2 set a world record for medium weight aircraft reaching an altitude of 68,700 feet. The

  20. Seasonality of bottom water temperature in the northern North Sea reconstructed from the oxygen isotope composition of the bivalve Arctica islandica

    Science.gov (United States)

    Trofimova, Tamara; Andersson, Carin; Bonitz, Fabian

    2017-04-01

    The seasonality of temperature changes is an important characteristic of climate. However, observational data for the ocean are only available for the last 150 year from a limited number of locations. Prior to 18th century information is only available from proxy reconstructions. The vast majority of such reconstructions depend on land-based archives, primarily from dendrochronology. Established marine proxy records for the ocean, especially at high latitudes, are both sparsely distributed and poorly resolved in time. Therefore, the identification and development of proxies for studying key ocean processes at sub-annual resolution that can extend the marine instrumental record is a clear priority in marine climate science. In this study, we have developed a record of early Holocene seasonal variability of bottom water temperature from the Viking Bank in the northern most North Sea. This area is of a particular interest since the hydrography is controlled by the inflow of Atlantic water. The reconstruction is based on the oxygen isotope composition of the growth increments in two sub-fossil shells of Arctica islandica (Bivalvia), dated to 9600-9335 cal. yr BP. By combining radiocarbon dating and sclerochronological techniques a floating chronology spanning over 200 years was constructed. Using the chronology as an age model, oxygen isotope measurements from 2 shells were combined into a 22-years long record. The results from this oxygen isotope record are compared with stable oxygen isotope profiles from modern shells to estimate changes in the mean state and seasonality between present and early Holocene. Shell-derived oxygen isotope values together with ice-volume corrected oxygen isotope values for the seawater were used to calculate bottom-water temperatures on a sub-annual time-scale. Preliminary results of the reconstructed early Holocene bottom water temperature indicate higher seasonality and lower minimum temperature compared to the present.

  1. Improving Protein Crystal Quality by the Without-Oil Microbatch Method: Crystallization and Preliminary X-ray Diffraction Analysis of Glutathione Synthetase from Pseudoalteromonas haloplanktis

    Directory of Open Access Journals (Sweden)

    Antonella Albino

    2011-09-01

    Full Text Available Glutathione synthetases catalyze the ATP-dependent synthesis of glutathione from L-γ-glutamyl-L-cysteine and glycine. Although these enzymes have been sequenced and characterized from a variety of biological sources, their exact catalytic mechanism is not fully understood and nothing is known about their adaptation at extremophilic environments. Glutathione synthetase from the Antarctic eubacterium Pseudoalteromonas haloplanktis (PhGshB has been expressed, purified and successfully crystallized. An overall improvement of the crystal quality has been obtained by adapting the crystal growth conditions found with vapor diffusion experiments to the without-oil microbatch method. The best crystals of PhGshB diffract to 2.34 Å resolution and belong to space group P212121, with unit-cell parameters a = 83.28 Å, b = 119.88 Å, c = 159.82 Å. Refinement of the model, obtained using phases derived from the structure of the same enzyme from Escherichia coli by molecular replacement, is in progress. The structural determination will provide the first structural characterization of a psychrophilic glutathione synthetase reported to date.

  2. Pilot-Scale Production and Thermostability Improvement of the M23 Protease Pseudoalterin from the Deep Sea Bacterium Pseudoalteromonas sp. CF6-2

    Directory of Open Access Journals (Sweden)

    Jie Yang

    2016-11-01

    Full Text Available Pseudoalterin is the most abundant protease secreted by the marine sedimental bacterium Pseudoalteromonas sp. CF6-2 and is a novel cold-adapted metalloprotease of the M23 family. Proteases of the M23 family have high activity towards peptidoglycan and elastin, suggesting their promising biomedical and biotechnological potentials. To lower the fermentive cost and improve the pseudoalterin production of CF6-2, we optimized the fermentation medium by using single factor experiments, added 0.5% sucrose as a carbon source, and lowered the usage of artery powder from 1.2% to 0.6%. In the optimized medium, pseudoalterin production reached 161.15 ± 3.08 U/mL, 61% greater than that before optimization. We further conducted a small-scale fermentation experiment in a 5-L fermenter and a pilot-scale fermentation experiment in a 50-L fermenter. Pseudoalterin production during pilot-scale fermentation reached 103.48 ± 8.64 U/mL, 77% greater than that before the medium was optimized. In addition, through single factor experiments and orthogonal tests, we developed a compound stabilizer for pseudoalterin, using medically safe sugars and polyols. This stabilizer showed a significant protective effect for pseudoalterin against enzymatic thermal denaturation. These results lay a solid foundation for the industrial production of pseudoalterin and the development of its biomedical and biotechnological potentials.

  3. Structural and functional characterization of mature forms of metalloprotease E495 from Arctic sea-ice bacterium Pseudoalteromonas sp. SM495.

    Directory of Open Access Journals (Sweden)

    Hai-Lun He

    Full Text Available E495 is the most abundant protease secreted by the Arctic sea-ice bacterium Pseudoalteromonas sp. SM495. As a thermolysin family metalloprotease, E495 was found to have multiple active forms in the culture of strain SM495. E495-M (containing only the catalytic domain and E495-M-C1 (containing the catalytic domain and one PPC domain were two stable mature forms, and E495-M-C1-C2 (containing the catalytic domain and two PPC domains might be an intermediate. Compared to E495-M, E495-M-C1 had similar affinity and catalytic efficiency to oligopeptides, but higher affinity and catalytic efficiency to proteins. The PPC domains from E495 were expressed as GST-fused proteins. Both of the recombinant PPC domains were shown to have binding ability to proteins C-phycocyanin and casein, and domain PPC1 had higher affinity to C-phycocyanin than domain PPC2. These results indicated that the domain PPC1 in E495-M-C1 could be helpful in binding protein substrate, and therefore, improving the catalytic efficiency. Site-directed mutagenesis on the PPC domains showed that the conserved polar and aromatic residues, D26, D28, Y30, Y/W65, in the PPC domains played key roles in protein binding. Our study may shed light on the mechanism of organic nitrogen degradation in the Arctic sea ice.

  4. Sequence and phylogenetic analysis of complete mitochondrial DNA genomes of two grasshopper species Gomphocerus rufus (Linnaeus, 1758) and Primnoa arctica (Zhang and Jin, 1985) (Orthoptera: Acridoidea).

    Science.gov (United States)

    Sun, Huimin; Zheng, Zhemin; Huang, Yuan

    2010-06-01

    In Xia's taxonomic revision, Gomphocerus rufus (Linnaeus, 1758), Chorthippus chinensis and Phlaeoba albonema belong to the families Gomphoceridae, Arcypteridae and Acrididae, respectively; whereas in Otte's taxonomic analysis of Orthoptera, all three species belong to the subfamily Gomphocerinae, family Acrididae. We determined the mitochondrial genomes (mitogenomes) of G. rufus, compared these with 10 other caeliferan mitogenomes, and performed phylogenetic analyses in order to clarify the relationships of the three families in Xia's taxonomic revision and which study is more accurate in defining the relationships of the three families. Furthermore, the mitogenome of Primnoa arctica (Zhang and Jin, 1985) was determined. This is the first mitogenome of the subfamily Catantopinae, superfamily Acridoidea. Through the comparison of mitogenomes from six subfamilies of the superfamily Acridoidea and one species of Pyrgomorphoidea, we hope to summarize a general law on the composition of the caeliferan mitogenome. The two molecules contain the same set of mitochondrial genes for 22 tRNAs, 2 rRNAs, 13 proteins, and a non-coding, AT-rich region. The base composition, gene order, and codon usage of the two genomes conform to those reported for other caeliferan species. Both genomes possess the rearrangement of tRNA(Lys) and tRNA(Asp). Compared with their ancestral mitogenome, this is a significant difference between the mitogenome of the suborders Caelifera and Ensifera or other Metazoa. A stem-loop structure that is similar to a previously presumed one (that probably involved in replication initiation) was found at the A+T-rich region of each mitogenome. In the phylogenetic analyses, the species from suborders Caelifera and Ensifera cluster, respectively, as monophyletic groups, and the two suborders cluster as sister groups. Within Caelifera, the subfamily Gomphocerinae appears to be a paraphyletic group in the analyses of the protein-coding gene (PCG) dataset and a

  5. Structural insights into the multispecific recognition of dipeptides of deep-sea gram-negative bacterium Pseudoalteromonas sp. strain SM9913.

    Science.gov (United States)

    Li, Chun-Yang; Chen, Xiu-Lan; Qin, Qi-Long; Wang, Peng; Zhang, Wei-Xin; Xie, Bin-Bin; Su, Hai-Nan; Zhang, Xi-Ying; Zhou, Bai-Cheng; Zhang, Yu-Zhong

    2015-03-01

    Peptide uptake is important for nutrition supply for marine bacteria. It is also an important step in marine nitrogen cycling. However, how marine bacteria absorb peptides is still not fully understood. DppA is the periplasmic dipeptide binding protein of dipeptide permease (Dpp; an important peptide transporter in bacteria) and exclusively controls the substrate specificity of Dpp. Here, the substrate binding specificity of deep-sea Pseudoalteromonas sp. strain SM9913 DppA (PsDppA) was analyzed for 25 different dipeptides with various properties by using isothermal titration calorimetry measurements. PsDppA showed binding affinities for 8 dipeptides. To explain the multispecific substrate recognition mechanism of PsDppA, we solved the crystal structures of unliganded PsDppA and of PsDppA in complex with 4 different types of dipeptides (Ala-Phe, Met-Leu, Gly-Glu, and Val-Thr). PsDppA alternates between an "open" and a "closed" form during substrate binding. Structural analyses of the 4 PsDppA-substrate complexes combined with mutational assays indicate that PsDppA binds to different substrates through a precise mechanism: dipeptides are bound mainly by the interactions between their backbones and PsDppA, in particular by anchoring their N and C termini through ion-pair interactions; hydrophobic interactions are important in binding hydrophobic dipeptides; and Lys457 is necessary for the binding of dipeptides with a C-terminal glutamic acid or glutamine. Additionally, sequence alignment suggests that the substrate recognition mechanism of PsDppA may be common in Gram-negative bacteria. All together, our results provide structural insights into the multispecific substrate recognition mechanism of marine Gram-negative bacterial DppA, which provides a better understanding of the mechanisms of marine bacterial peptide uptake. Peptide uptake plays a significant role in nutrition supply for marine bacteria. It is also an important step in marine nitrogen cycling. However

  6. Characterization of a New Cold-Adapted and Salt-Activated Polysaccharide Lyase family 7 Alginate Lyase from Pseudoalteromonas sp. SM0524

    Directory of Open Access Journals (Sweden)

    Xiu-Lan Chen

    2016-07-01

    Full Text Available Marine bacterial alginate lyases play a role in marine alginate degradation and carbon cycling. Although a large number of alginate lyases have been characterized, reports on alginate lyases with special characteristics are still rather less. Here, a gene alyPM encoding an alginate lyase of polysaccharide lyase family 7 (PL7 was cloned from marine Pseudoalteromonas sp. SM0524 and expressed in Escherichia coli. AlyPM shows 41% sequence identity to characterized alginate lyases, indicating that AlyPM is a new PL7 enzyme. The optimal pH for AlyPM activity was 8.5. AlyPM showed the highest activity at 30oC and remained 19% of the highest activity at 5oC. AlyPM was unstable at temperatures above 30oC and had a low Tm of 37oC. These data indicate that AlyPM is a cold-adapted enzyme. Moreover, AlyPM is a salt-activated enzyme. AlyPM activity in 0.5-1.2 M NaCl was 6-fold higher than that in 0 M NaCl, probably caused by a significant increase in substrate affinity, because the Km of AlyPM in 0.5 M NaCl decreased more than 20 folds than that in 0 M NaCl. AlyPM preferably degraded polymannuronate and mainly released dimers and trimers. These data indicate that AlyPM is a novel PL7 endo-alginate lyase with special characteristics.

  7. Molecular cloning, expression and enzymatic characterization of glutathione S-transferase from Antarctic sea-ice bacteria Pseudoalteromonas sp. ANT506.

    Science.gov (United States)

    Shi, Yonglei; Wang, Quanfu; Hou, Yanhua; Hong, Yanyan; Han, Xiao; Yi, Jiali; Qu, Junjie; Lu, Yi

    2014-01-01

    A glutathione S-transferase (GST) gene from Antarctic sea-ice bacteria Pseudoalteromonas sp. ANT506 (namely PsGST), was cloned and expressed in Escherichia coli. The open reading frame of PsGST comprised 654 bp encoding a protein of 217 amino acids with a calculated molecular size of 24.3 kDa. The rPsGST possesses the conserved amino acid defining the binding sites of glutathione (G-site) and substrate binding pocket (H-site) in GST N_3 family. PsGST was expressed in E. coli and the recombinant PsGST (rPsGST) was purified by Ni-affinity chromatography with a high specific activity of 74.21 U/mg. The purified rPsGST showed maximum activity at 40 °C and exhibited 14.2% activity at 0 °C. It was completely inactivated at 50 °C for 40 min. These results indicated that rPsGST was a typical cold active GST with low thermostability. The enzyme was little affected by H2O2 and Triton X-100, and 50.2% of the remaining activity was detected in the presence of high salt concentrations (2M NaCl). The enzymatic Km values for CDNB and GSH was 0.22 mM and 1.01 mM, respectively. These specific enzyme properties may be related to the survival environment of Antarctic sea ice bacteria. Copyright © 2013 Elsevier GmbH. All rights reserved.

  8. Anti-Biofilm Activity of a Long-Chain Fatty Aldehyde from Antarctic Pseudoalteromonas haloplanktis TAC125 against Staphylococcus epidermidis Biofilm.

    Science.gov (United States)

    Casillo, Angela; Papa, Rosanna; Ricciardelli, Annarita; Sannino, Filomena; Ziaco, Marcello; Tilotta, Marco; Selan, Laura; Marino, Gennaro; Corsaro, Maria M; Tutino, Maria L; Artini, Marco; Parrilli, Ermenegilda

    2017-01-01

    Staphylococcus epidermidis is a harmless human skin colonizer responsible for ~20% of orthopedic device-related infections due to its capability to form biofilm. Nowadays there is an interest in the development of anti-biofilm molecules. Marine bacteria represent a still underexploited source of biodiversity able to synthesize a broad range of bioactive compounds, including anti-biofilm molecules. Previous results have demonstrated that the culture supernatant of Antarctic marine bacterium Pseudoalteromonas haloplanktis TAC125 impairs the formation of S. epidermidis biofilm. Further, evidence supports the hydrophobic nature of the active molecule, which has been suggested to act as a signal molecule. In this paper we describe an efficient activity-guided purification protocol which allowed us to purify this anti-biofilm molecule and structurally characterize it by NMR and mass spectrometry analyses. Our results demonstrate that the anti-biofilm molecule is pentadecanal, a long-chain fatty aldehyde, whose anti-S. epidermidis biofilm activity has been assessed using both static and dynamic biofilm assays. The specificity of its action on S. epidermidis biofilm has been demonstrated by testing chemical analogs of pentadecanal differing either in the length of the aliphatic chain or in their functional group properties. Further, indications of the mode of action of pentadecanal have been collected by studying the bioluminescence of a Vibrio harveyi reporter strain for the detection of autoinducer AI-2 like activities. The data collected suggest that pentadecanal acts as an AI-2 signal. Moreover, the aldehyde metabolic role and synthesis in the Antarctic source strain has been investigated. To the best of our knowledge, this is the first report on the identification of an anti-biofilm molecule form from cold-adapted bacteria and on the action of a long-chain fatty aldehyde acting as an anti-biofilm molecule against S. epidermidis.

  9. Effects of ambient versus reduced UV-B radiation on high arctic ¤Salix arctica¤ assessed by measurements and calculations of chlorophyll a fluorescence parameters from fluorescence transients

    DEFF Research Database (Denmark)

    Albert, K.R.; Mikkelsen, Teis Nørgaard; Ro-Poulsen, H.

    2005-01-01

    A UV-B exclusion-experiment was conducted in the high Arctic Zackenberg, NE Greenland, in which Salix arctica leaves during most of the growing season were fixed perpendicular to the solar zenith angle, thereby receiving maximal solar radiation. Covered with Teflon and Mylar foil, the leaves...... of evaluating the relative importance of UV-B of donor and acceptor side capacity in Photosystem II. In conclusion, the experimental set-up and non-invasive measurements proved to be a sensitive method to screen for effects of UV-B stress....... received approximately 90 and 40% of the ambient UV-B irradiance, respectively. The effects were examined through recordings of chlorophyll a fluorescence transients, determination of biomass and analysis of total carbon and nitrogen content and amount of soluble flavonoids in the leaves. The processing...

  10. A heart that beats for 500 years: age-related changes in cardiac proteasome activity, oxidative protein damage and expression of heat shock proteins, inflammatory factors, and mitochondrial complexes in Arctica islandica, the longest-living noncolonial animal.

    Science.gov (United States)

    Sosnowska, Danuta; Richardson, Chris; Sonntag, William E; Csiszar, Anna; Ungvari, Zoltan; Ridgway, Iain

    2014-12-01

    Study of negligibly senescent animals may provide clues that lead to better understanding of the cardiac aging process. To elucidate mechanisms of successful cardiac aging, we investigated age-related changes in proteasome activity, oxidative protein damage and expression of heat shock proteins, inflammatory factors, and mitochondrial complexes in the heart of the ocean quahog Arctica islandica, the longest-lived noncolonial animal (maximum life span potential: 508 years). We found that in the heart of A. islandica the level of oxidatively damaged proteins did not change significantly up to 120 years of age. No significant aging-induced changes were observed in caspase-like and trypsin-like proteasome activity. Chymotrypsin-like proteasome activity showed a significant early-life decline, then it remained stable for up to 182 years. No significant relationship was observed between the extent of protein ubiquitination and age. In the heart of A. islandica, an early-life decline in expression of HSP90 and five mitochondrial electron transport chain complexes was observed. We found significant age-related increases in the expression of three cytokine-like mediators (interleukin-6, interleukin-1β, and tumor necrosis factor-α) in the heart of A. islandica. Collectively, in extremely long-lived molluscs, maintenance of protein homeostasis likely contributes to the preservation of cardiac function. Our data also support the concept that low-grade chronic inflammation in the cardiovascular system is a universal feature of the aging process, which is also manifest in invertebrates. © The Author 2013. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  11. Phylogenetic analyses of the genus Glaciecola: emended description of the genus Glaciecola, transfer of Glaciecola mesophila, G. agarilytica, G. aquimarina, G. arctica, G. chathamensis, G. polaris and G. psychrophila to the genus Paraglaciecola gen. nov. as Paraglaciecola mesophila comb. nov., P. agarilytica comb. nov., P. aquimarina comb. nov., P. arctica comb. nov., P. chathamensis comb. nov., P. polaris comb. nov. and P. psychrophila comb. nov., and description of Paraglaciecola oceanifecundans sp. nov., isolated from the Southern Ocean.

    Science.gov (United States)

    Shivaji, Sisinthy; Reddy, Gundlapally Sathyanarayana

    2014-09-01

    Phylogenetic analyses of the genus Glaciecola were performed using the sequences of the 16S rRNA gene and the GyrB protein to establish its taxonomic status. The results indicated a consistent clustering of the genus Glaciecola into two clades, with significant bootstrap values, with all the phylogenetic methods employed. Clade 1 was represented by seven species, Glaciecola agarilytica, G. aquimarina, G. arctica, G. chathamensis, G. mesophila, G. polaris and G. psychrophila, while clade 2 consisted of only three species, Glaciecola nitratireducens, G. pallidula and G. punicea. Evolutionary distances between species of clades 1 and 2, based on 16S rRNA gene and GyrB protein sequences, ranged from 93.0 to 95.0 % and 69.0 to 73.0 %, respectively. In addition, clades 1 and 2 possessed 18 unique signature nucleotides, at positions 132, 184 : 193, 185 : 192, 230, 616 : 624, 631, 632, 633, 738, 829, 1257, 1265, 1281, 1356 and 1366, in the 16S rRNA gene sequence and can be differentiated by the occurrence of a 15 nt signature motif 5'-CAAATCAGAATGTTG at positions 1354-1368 in members of clade 2. Robust clustering of the genus Glaciecola into two clades based on analysis of 16S rRNA gene and GyrB protein sequences, 16S rRNA gene sequence similarity of ≤95.0 % and the occurrence of signature nucleotides and signature motifs in the 16S rRNA gene suggested that the genus should be split into two genera. The genus Paraglaciecola gen. nov. is therefore created to accommodate the seven species of clade 1, while the name Glaciecola sensu stricto is retained to represent species of clade 2. The species of clade 1 are transferred to the genus Paraglaciecola as Paraglaciecola mesophila comb. nov. (type strain DSM 15026(T) = KMM 241(T)), P. agarilytica comb. nov. (type strain NO2(T) = KCTC 12755(T) = LMG 23762(T)), P. aquimarina comb. nov. (type strain GGW-M5(T) = KCTC 32108(T) = CCUG 62918(T)), P. arctica comb. nov. (type strain BSs20135(T

  12. Pseudochelin A, a siderophore of Pseudoalteromonas piscicida S2040

    DEFF Research Database (Denmark)

    Sonnenschein, Eva; Stierhof, Marc; Goralczyk, Stephan

    2017-01-01

    techniques including 2D NMR and MS/MS fragmentation data. In bioassays selected fractions of the crude extract of S2040 inhibited the opportunistic pathogen Pseudomonas aeruginosa. Pseudochelin A displayed siderophore activity in the chrome azurol S assay at concentrations higher than 50 μM, and showed weak...

  13. Vermistella arctica n. sp. Nominates the Genus Vermistella as a Candidate for Taxon with Bipolar Distribution

    Czech Academy of Sciences Publication Activity Database

    Tyml, Tomáš; Kostka, Martin; Ditrich, O.; Dyková, I.

    2016-01-01

    Roč. 63, č. 2 (2016), s. 210-219 ISSN 1066-5234 R&D Projects: GA ČR(CZ) GBP505/12/G112 Institutional support: RVO:60077344 Keywords : actin * biogeography * bipolar distribution * free-living amoebae * phylogeny * polar regions * SSU Subject RIV: EG - Zoology Impact factor: 2.692, year: 2016

  14. The winter diet of the Atlantic Puffin Fratercula arctica around the Faroe Islands

    NARCIS (Netherlands)

    Harris, M.P.; Leopold, M.F.; Jensen, J.; Meesters, H.W.G.; Wanless, S.

    2015-01-01

    Most mortality of Atlantic Puffins occurs outside the breeding season but little is known about the species’ diet at that time. The stomach contents of 176 Puffins shot legally for food around the Faroe Islands between October and January in three winters were examined. The remains of 20 species of

  15. Sarcocystis arctica (Apicomplexa: Sarcocystidae): ultrastructural description and its new host record, the Alaskan wolf (Canis lupus

    Science.gov (United States)

    Sarcocystis sarcocysts are common in muscles of herbivores but are rare in muscles of carnivores. Here, we report sarcocysts in muscle of an Alaskan wolf (Canis lupus) from Alaska, USA for the first time. Sarcocysts extracted from tongue of the wolf were up to 900 µm long, slender, and appeared to h...

  16. Isolation and Structure Elucidation of a Novel Yellow Pigment from the Marine Bacterium Pseudoalteromonas tunicata

    Directory of Open Access Journals (Sweden)

    N. Kumar

    2005-10-01

    Full Text Available The marine environment is a major source for many novel natural compounds. A new yellow pigment has been isolated from the marine bacterium P. tunicata and identified as a new member of the tambjamine class of compounds. The structural identification was achieved by a combination of 1D and 2D-NMR spectroscopy and high resolution mass spectrometry data.

  17. Hydrographical variability and major ecosystem changes as recorded in the growth of Arctica islandica from the northern North Sea

    Science.gov (United States)

    Trofimova, Tamara; Andersson, Carin; Bonitz, Fabian

    2017-04-01

    Reconstruction of marine climate variability on regional to global scales requires a network of climatically sensitive annually resolved archives from key oceanographic locations. The small number of records existing to date impedes the application of a network approach. In this study, we aim at improving the spatial coverage of annually resolved paleo proxy records by investigating the impact of climate variability on sclerochronological records of A. islandica from the Viking Bank in the northern North Sea. The northern North Sea has an excellent oceanographic setting because its hydrography is primarily controlled by the major Atlantic water inflow to the North Sea. Using annual growth increment measurements of 30 shells we constructed a 265-year shell-growth chronology spanning the time interval AD 1748-2013. Chronology statistics (Rbar (>0.5) and EPS (>0.85)) indicate a robust signal of a common environmental forcing controlling shell growth for the major part of the record. Comparison with other sclerochronologies from the oceanographically related locations reveals a coherency on longer time scales, which is likely a response to a common environmental driver or a combination of such drivers. No significant correlation on the year-on-year level has been found between the chronology and time series of temperature and salinity from the area close to the study site. However, the timing of major hydrographical anomalies described for the region (Great Salinity Anomalies) coincide with a decrease in shell growth; likely in response to an impact on lower trophic levels, i.e. plankton composition and abundance. Spectral analysis of the chronology reveals a 21-26 year periodicity recorded in the shell growth. The variability on a similar time scale has been observed in multiple records from the North Atlantic and in model outputs. It has been suggested to represent one of the dominant scales of multi-decadal variability especially pronounced prior to the 20th century. In our chronology this variability is clearly observed prior to the 1920's and fades out towards present day. This change coincides with the most significant regime shift in the North Atlantic observed in the 20th-century, connected with dramatic warming and increasing Atlantic inflow. Hence, our data show that growth chronology from the Viking Bank region has a high potential to be used in climate variability studies and can significantly contribute to the development of a spatial sclerochronological network.

  18. Gene Sequence Based Clustering Assists in Dereplication of Pseudoalteromonas luteoviolacea Strains with Identical Inhibitory Activity and Antibiotic Production

    DEFF Research Database (Denmark)

    Vynne, Nikolaj Grønnegaard; Månsson, Maria; Gram, Lone

    2012-01-01

    Some microbial species are chemically homogenous, and the same secondary metabolites are found in all strains. In contrast, we previously found that five strains of P. luteoviolacea were closely related by 16S rRNA gene sequence but produced two different antibiotic profiles. The purpose of the p......Some microbial species are chemically homogenous, and the same secondary metabolites are found in all strains. In contrast, we previously found that five strains of P. luteoviolacea were closely related by 16S rRNA gene sequence but produced two different antibiotic profiles. The purpose...... of the present study was to determine whether such bioactivity differences could be linked to genotypes allowing methods from phylogenetic analysis to aid in selection of strains for biodiscovery. Thirteen P. luteoviolacea strains divided into three chemotypes based on production of known antibiotics and four...... correlation to chemotypes and inhibition profiles, while clustering based on concatenated 16S rRNA, gyrB, and recA gene sequences resulted in three clusters, two of which uniformly consisted of strains of identical chemotype and inhibition profile. A major time sink in natural products discovery is the effort...

  19. An ortholog of the Leptospira interrogans lipoprotein LipL32 aids in the colonization of Pseudoalteromonas tunicata to host surfaces

    Directory of Open Access Journals (Sweden)

    Melissa eGardiner

    2014-07-01

    Full Text Available The bacterium P. tunicata is a common surface colonizer of marine eukaryotes, including the macroalga Ulva australis. Genomic analysis of P. tunicata identified genes potentially involved in surface colonization, including genes with homology to bacterial virulence factors that mediate attachment. Of particular interest is the presence of a gene, designated ptlL32, encoding an ortholog to the Leptospira lipoprotein LipL32, which has been shown to facilitate the interaction of Leptospira sp. with host extracellular matrix (ECM structures and is thought to be an important virulence trait for pathogenic Leptospira. To investigate the role of PtlL32 in the colonization by P. tunicata we constructed and characterized a ΔptlL32 mutant strain. Whilst P. tunicata ΔptlL32 bound to an abiotic surface with the same capacity as the wild type strain, it had a marked effect on the ability of P. tunicata to bind to ECM, suggesting a specific role in attachment to biological surfaces. Loss of PtlL32 also significantly reduced the capacity for P. tunciata to colonize the host algal surface demonstrating a clear role for this protein as a host-colonization factor. PtlL32 appears to have a patchy distribution across specific groups of environmental bacteria and phylogenetic analysis of PtlL32 orthologous proteins from non-Leptospira species suggests it may have been acquired via horizontal gene transfer between distantly related lineages. This study provides the first evidence for an attachment function for a LipL32- like protein outside the Leptospira and thereby contributes to the understanding of host colonization in ecologically distinct bacterial species.

  20. Gene Sequence Based Clustering Assists in Dereplication of Pseudoalteromonas luteoviolacea Strains with Identical Inhibitory Activity and Antibiotic Production

    Directory of Open Access Journals (Sweden)

    Lone Gram

    2012-08-01

    Full Text Available Some microbial species are chemically homogenous, and the same secondary metabolites are found in all strains. In contrast, we previously found that five strains of P. luteoviolacea were closely related by 16S rRNA gene sequence but produced two different antibiotic profiles. The purpose of the present study was to determine whether such bioactivity differences could be linked to genotypes allowing methods from phylogenetic analysis to aid in selection of strains for biodiscovery. Thirteen P. luteoviolacea strains divided into three chemotypes based on production of known antibiotics and four antibacterial profiles based on inhibition assays against Vibrio anguillarum and Staphylococcus aureus. To determine whether chemotype and inhibition profile are reflected by phylogenetic clustering we sequenced 16S rRNA, gyrB and recA genes. Clustering based on 16S rRNA gene sequences alone showed little correlation to chemotypes and inhibition profiles, while clustering based on concatenated 16S rRNA, gyrB, and recA gene sequences resulted in three clusters, two of which uniformly consisted of strains of identical chemotype and inhibition profile. A major time sink in natural products discovery is the effort spent rediscovering known compounds, and this study indicates that phylogeny clustering of bioactive species has the potential to be a useful dereplication tool in biodiscovery efforts.

  1. Production of the Bioactive Compounds Violacein and Indolmycin Is Conditional in a maeA Mutant of Pseudoalteromonas luteoviolacea i>S4054 Lacking the Malic Enzyme

    DEFF Research Database (Denmark)

    Schmidt Thøgersen, Mariane; Delpin, Marina; Melchiorsen, Jette

    2016-01-01

    cluster was not interrupted by the transposon; instead the insertion was located to the maeA gene encoding the malic enzyme. Supernatant of the mutant strain inhibited Vibrio anguillarum and Staphylococcus aureus in well diffusion assays and in MIC assays at the same level as the wild type strain....... The mutant strain killed V. anguillarum in co-culture experiments as efficiently as the wild type. Using UHPLC-UV/Vis analyses, we quantified violacein and indolmycin, and the mutant strain only produced 7-10% the amount of violacein compared to the wild type strain. In contrast, the amount of indolmycin...... produced by the mutant strain was about 300% that of the wild type. Since inhibition of V. anguillarum and S. aureus by the mutant strain was similar to that of the wild type, it is concluded that violacein is not the major antibacterial compound in P. luteoviolacea. We furthermore propose that production...

  2. Psychrophilic sulfate-reducing bacteria isolated from permanently cold Arctic marine sediments: description of Desulfofrigrus oceanense gen. nov., sp nov., Desulfofrigus fragile sp nov., Desulfofaba gelida gen. nov., sp nov., Desulfotalea psychrophila gen. nov., sp nov and Desulfotalea arctica sp

    DEFF Research Database (Denmark)

    Knoblauch, C.; Sahm, K.; Jørgensen, BB

    1999-01-01

    known sulfate reducers. Due to the phylogenetic and phenotypic differences between the new isolates and their closest relatives, establishment of the new genera Desulfotalea gen. nov., Desulfofaba gen. nov. and Desulfofrigus gen. nov. is proposed, with strain ASv26(T) as the type strain of the type...

  3. The occurrence of auks Alcidae at Blaavandshuk, southwest Jutland, 1963-1985

    DEFF Research Database (Denmark)

    Mouritsen, Kim Nørgaard

    1991-01-01

    Keywords: Alca torda, Uria aalge, Cepphus grylle, Alle alle, Fratercula arctica, migration, North Sea movements, wind direction, wind force, cyclone passages, change in occurrence, prey.......Keywords: Alca torda, Uria aalge, Cepphus grylle, Alle alle, Fratercula arctica, migration, North Sea movements, wind direction, wind force, cyclone passages, change in occurrence, prey....

  4. NCBI nr-aa BLAST: CBRC-DDIS-04-0172 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-DDIS-04-0172 ref|YP_662269.1| diguanylate cyclase [Pseudoalteromonas atlantica... T6c] gb|ABG41215.1| diguanylate cyclase [Pseudoalteromonas atlantica T6c] YP_662269.1 0.76 29% ...

  5. NCBI nr-aa BLAST: CBRC-CREM-01-1302 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-CREM-01-1302 ref|YP_660676.1| acyltransferase 3 [Pseudoalteromonas atlantica T...6c] gb|ABG39622.1| acyltransferase 3 [Pseudoalteromonas atlantica T6c] YP_660676.1 3e-77 52% ...

  6. NCBI nr-aa BLAST: CBRC-CREM-01-1308 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-CREM-01-1308 ref|YP_661165.1| protein of unknown function DUF1275 [Pseudoalteromonas atlantic...a T6c] gb|ABG40111.1| protein of unknown function DUF1275 [Pseudoalteromonas atlantica T6c] YP_661165.1 1e-40 41% ...

  7. NCBI nr-aa BLAST: CBRC-AGAM-07-0034 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-AGAM-07-0034 ref|YP_661398.1| major facilitator superfamily MFS_1 [Pseudoalteromonas atlantic...a T6c] gb|ABG40344.1| major facilitator superfamily MFS_1 [Pseudoalteromonas atlantica T6c] YP_661398.1 5e-57 45% ...

  8. NCBI nr-aa BLAST: CBRC-XTRO-01-0220 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-XTRO-01-0220 ref|YP_662989.1| Strictosidine synthase [Pseudoalteromonas atlantic...a T6c] gb|ABG41935.1| Strictosidine synthase [Pseudoalteromonas atlantica T6c] YP_662989.1 3e-53 38% ...

  9. NCBI nr-aa BLAST: CBRC-BTAU-01-2762 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-BTAU-01-2762 ref|YP_660210.1| diguanylate cyclase/phosphodiesterase [Pseudoalteromonas atlantic...a T6c] gb|ABG39156.1| diguanylate cyclase/phosphodiesterase [Pseudoalteromonas atlantica T6c] YP_660210.1 1.5 23% ...

  10. NCBI nr-aa BLAST: CBRC-DMEL-01-0046 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-DMEL-01-0046 ref|YP_663210.1| NAD(P) transhydrogenase, beta subunit [Pseudoalteromonas atlantic...a T6c] gb|ABG42156.1| NAD(P) transhydrogenase, beta subunit [Pseudoalteromonas atlantica T6c] YP_663210.1 0.026 26% ...

  11. Algues Carbonifères et Permiennes de l'Arctique Canadien

    National Research Council Canada - National Science Library

    Mamet, B L; Roux, A; Nassichuk, W W

    1987-01-01

    .... Five genera are new: Ellesmerella n. gen. (type: E. permica (Pia)), Halimedoides n. gen . (type: H. arctica n. sp.), Nansenella n. gen. (type: N. multiramosa n. sp.), Richella n. gen. (type: R. incrustata n. sp.) and Stacheoidella...

  12. NEFSC 2002 Surfclam and Ocean Quahog Survey (DE0206, EK500)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The 2002 region-wide survey for Atlantic surfclam (Spisula solidissima) and Ocean Quahog (Arctica islandica) was conducted in continental shelf waters, from Delmarva...

  13. First record of Hyalascus (Hexactinellida: Rossellidae) from the Indian Ocean, with description of a new species from a volcanic seamount in the Andaman Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Sautya, S.; Tabachnick, K.R.; Ingole, B.S.

    . & Schaudinn, F. (Eds), Fauna Arctica. Eine Zusammenstellung der arktischen Tierformen mit besonderer Berücksichtigung des Spitzbergen-Gebietes auf Grund der Ergebnisse der Deutschen Expedition in das Nördliche Eismeer im Jahre 1898. Band 1 (1). Tabachnick...

  14. Catechin content and consumption ratio of the collared lemming

    DEFF Research Database (Denmark)

    Berg, Thomas B.

    2003-01-01

    catechin content. Dicrostonyx species are known to have specialised on shrubs, especially Dryas spp. and Salix spp., rather than graminoids like other related microtines. Bioassays were conducted using food material from Dryas spp., Salix arctica, Vaccinium uliginosum, Kobresia myosuroides and Poa glauca....... Enclosures with the first three species mentioned were further treated by clipping to simulate herbivory in order to induce the production of the plant defence compound catechin. Treatment increased the catechin content in Dryas spp., S. arctica (females only) and V. uliginosum significantly compared...... with the catechin concentration in untreated plants. These elevated catechin concentrations had a significantly negative effect on the consumption rate of Dryas spp. and female S. arctica by collared lemmings....

  15. [Effect of excretion-secretion products of some fouling species on the biochemical parameters of blue mussel Mytilus edulis L. (Mollusca: Bivalvia) in the White Sea].

    Science.gov (United States)

    Skidchenko, V S; Vysotskaia, R U; Krupnova, M Iu; Khalaman, V V

    2011-01-01

    The effect of excretion-secretion products (ESP) of five abundant fouling invertebrate species (bivalve mollusks Hiatella arctica and Mytilus edulis, solitary ascidia Styela rustica, sponge Halichondria panicea, and sea starAsterias rubens, inhabiting the White Sea) on the biochemical status of blue mussel M. edulis was assessed by the dynamics of lysosomal enzymes activity (nucleases, glycoside hydrolases, and cathepsins). ESP of conspecific species had no effect on the metabolism of the mollusks of this species. ESP of A. rubens, S. rustica, and H. panicea activated the same enzymes. First, acid RNase and glycoside hydrolases activity increased, but in different ways. The metabolites of H. arctica affected the activity of proteometabolism enzymes.

  16. ICTV Virus Taxonomy Profile: Corticoviridae.

    Science.gov (United States)

    Oksanen, Hanna M; Ictv Report Consortium

    2017-05-01

    The Corticoviridae is a family of icosahedral, internal-membrane-containing viruses with double-stranded circular DNA genomes of approximately 10 kb. Only one species, Pseudoalteromonas virus PM2, has been recognized. Pseudoalteromonas virus PM2 infects Gram-negative bacteria and was isolated from seawater in 1968. Pseudoalteromonas virus PM2 is the first bacterial virus in which the presence of lipids in the virion has been demonstrated. Viral lipids are acquired selectively during virion assembly from the host cytoplasmic membrane. The outer protein capsid is an icosahedron with a pseudo T=21 symmetry. This is a summary of the International Committee on Taxonomy of Viruses (ICTV) Report on the taxonomy of the Corticoviridae, which is available at www.ictv.global/report/corticoviridae.

  17. Transmission electron microscopy of apical cells of Sphacelaria spp. (Sphacelariales, Phaeophyceae)

    NARCIS (Netherlands)

    Prud’homme van Reine, W.F.; Star, W.

    1981-01-01

    The ultrastructure of apical cells of six species of Sphacelaria (S. arctica, S. cirrosa, S. nana, S. racemosa, S. radicans, and S. rigidula) is studied here. In most details such as ultrastructure of chloroplasts, mitochondria, microbodies, nuclei and centrioles all Sphacelaria species studied are

  18. Baltic Sea coccolithophores - an overview of insights into their taxonomy and ecology from the last 40 years

    DEFF Research Database (Denmark)

    Thomsen, Helge Abildhauge

    2016-01-01

    coccolithophores (i.e. Balaniger virgulosa HOL and HET, Papposphaera arctica HOL cfr. and Papposphaera iugifera). When including here also material examined from the Danish transitional waters connecting the North Sea and the Baltic proper, it is possible to generally support the presence in the western Baltic...

  19. Interim Regional Supplement to the Corps of Engineers Wetland Delineation Manual: Alaska Region

    Science.gov (United States)

    2006-02-01

    Aster sibiricus FAC Galium boreale FACU Athyrium filix-femina FAC Geocaulon lividum FACU Beckmannia eruciformis OBL Geranium erianthum NI Betula...Artemisia arctica UPL Geranium pratense FAC Artemisia tilesii UPL Geum calthifolium FACW Athyrium filix-femina FAC Geum macrophyllum FACW Bromus

  20. An Ecological Land Survey for Fort Greely, Alaska

    Science.gov (United States)

    2001-02-01

    signifies >60% frequency within ecotype.) a. Alpine. Diapensia lapponica 0 1 Trisetum spicatum 0 0 0 Artemisia arctica 0 1 1 Saxifraga tricuspidata 1 0 0...Racomitrium lanuginosum 3 1 1 Rhytidium rugosum 1 1 1 Calamagrostis purpurascens 3 1 Stereocaulon spp. 1 4 2 Saxifraga punctata 0 0 Oxytropis nigrescens

  1. Strontium (87Sr/86Sr) dating of marine shells from pliocene and pleistocene shallow marine deposits in The Netherlands

    NARCIS (Netherlands)

    Jansen, H.S.M.; Huizer, J.; Dijkmans, J.W.A.; Hinte, J.E. van

    2004-01-01

    87Sr/86Sr (Strontium) ratio analyses of shell material (mainly Arctica islandica) from 24 levels in the Maassluis Formation of boreholes Noordwijk, Zegveld and Terschelling suggest that the age of the formation ranges from 0.82 to 2.34 Ma (± 0.5 Ma), and that the Oosterhout Formation at Noordwijk

  2. Exploring the calcium isotope signature of

    NARCIS (Netherlands)

    Hippler, D.; Witbaard, R.; van Aken, H.M.; Buhl, D.; Immenhauser, A.

    2013-01-01

    The calcium-isotope composition (delta Ca-44/40) of the aragonitic bivalve Arctica islandica grown in laboratory and field cultures was investigated in terms of environmental and biological controls to explore its potential as a palaeoceanographic proxy. While we found no significant effect of

  3. Chitin elicitation of natural product production in marine bacteria

    DEFF Research Database (Denmark)

    Månsson, Maria; Wietz, Matthias; Larsen, Thomas Ostenfeld

    -negative bacteria (mainly Pseudoalteromonas and Vibrio), we found that some strains were capable of producing antibacterial compounds when grown on chitin, an N-acetyl-D-glucosamine polymer found in the exoskeleton of zooplankton.2 A strain of Vibrio coralliilyticus solely produced the antibiotic andrimid,3...

  4. Enhanced Biofilm Formation and Increased Resistance to Antimicrobial Agents and Bacterial Invasion Are Caused by Synergistic Interactions in Multispecies Biofilms

    DEFF Research Database (Denmark)

    Burmølle, Mette; Webb, J.S.; Rao, D.

    2006-01-01

    versus nonexposed biofilms) of the four-species biofilm was markedly higher than that in any of the single-species biofilms. Moreover, in biofilms established on glass surfaces in flow cells and subjected to invasion by the antibacterial protein-producing Pseudoalteromonas tunicata, the four...

  5. Nitrogen regulates chitinase gene expression in a marine bacterium

    DEFF Research Database (Denmark)

    Delpin, Marina; Goodman, A.E.

    2009-01-01

    Ammonium concentration and nitrogen source regulate promoter activity and use for the transcription of chiA, the major chitinase gene of Pseudoalteromonas sp. S91 and S91CX, an S91 transposon lacZ fusion mutant. The activity of chiA was quantified by beta-galactosidase assay of S91CX cultures...

  6. Research Article Special Issue

    African Journals Online (AJOL)

    pc

    2017-11-10

    Nov 10, 2017 ... waste motor oil. 15 days for 1% (v/v) spent engine oil. 10 days for 1-75 μL of industrial oil. 3 days for 5.3% of hydrocarbon consumption. Nostochatei. Pseudoalteromonas sp., ... manganese dependent peroxidase, laccase and hydrogen peroxide-producing enzyme [7]. Fungi present a great potential for ...

  7. Pseudomonas piscicida kills vibrios by two distinct mechanisms

    Science.gov (United States)

    Pseudoalteromonas piscicida is a naturally-occurring marine bacterium which kills competing bacteria, including vibrios. In studies by Richards et al. (AEM00175-17), three strains of P. piscicida were isolated and characterized. Strains secreted proteolytic enzymes which likely killed competing or...

  8. Molecular identification of the microbiota of peeled and unpeeled brown shrimp (Crangon crangon) during storage on ice and at 7.5 °C.

    Science.gov (United States)

    Broekaert, Katrien; Heyndrickx, Marc; Herman, Lieve; Devlieghere, Frank; Vlaemynck, Geertrui

    2013-12-01

    The dominant microbiota of brown shrimp (Crangon crangon) were systematically identified during storage under different conditions. Freshly caught shrimp were processed on board the fishing vessel under the best possible hygienic conditions (IDEAL), unpeeled and manually (sterile) peeled, then stored on ice and at 7.5 °C until microbiologically spoiled. Results were compared with industrially processed (INDUSTRIAL) shrimp. Isolates grown on various media were identified by 16S rRNA and gyrB gene sequencing. We examined the total microbiota and microbial population shifts of shrimp under various storage conditions using denaturant gradient gel electrophoresis (DGGE). The microbiota differed somewhat during storage and among the various storage conditions; however, members of the genera Psychrobacter and Pseudoalteromonas were found to dominate the microbiota of all shrimp samples regardless of processing procedures or storage conditions. Most isolates could be identified by gyrB gene sequencing as Psychrobacter immobilis or Psychrobacter cibarius. Also Pseudoalteromonas nigrifaciens, Pseudoalteromonas elyakovii or Pseudoalteromonas paragorgicola dominated the microbiota of brown shrimp during storage. Also species from the genera Planocuccus, Exiguobacterium, Carnobacterium, Pseudomonas, Chryseobacterium and Staphylococcus were detected during storage of brown shrimp. Culture-dependent and culture-independent DGGE analysis produced different results in band patterns. Both methods are therefore required to accurately identify the microbiota and bacterial population shifts on seafood during storage. Copyright © 2013 Elsevier Ltd. All rights reserved.

  9. Preliminary Guide to the Onsite Identification and Delineation of the Wetlands of Alaska.

    Science.gov (United States)

    1984-02-01

    Sphagnum moss) * d Common associated species include: Alopecurus aequalis (Short-awn foxtail) Athyrium filix-femina (Lady fern) Calamagrostis...parnassus Parnassia kotzebuei Chain. and Schlecht. Labrador-tea .’ Leduam palustre L. Lady fern Athyrium filix-femina (L.) Roth B4 Large-flower speargrass...bearberry Artemisia arctica Less. Wormwood Artemisia spp. Wormwood Artemizsia tilesii Ledeb. 0 Wormwood Athyrium filix-femina (L.) Roth Lady fern Atriplex

  10. Age-related cellular changes in the long-lived bivalve A. islandica

    OpenAIRE

    Gruber, Heike; Wessels, Wiebke; Boynton, Primrose; Xu, Jinze; Wohlgemuth, Stephanie; Leeuwenburgh, Christiaan; Qi, Wenbo; Austad, Steven N.; Schaible, Ralf; Philipp, Eva E.R.

    2015-01-01

    One of the biggest challenges to studying causes and effects of aging is identifying changes in cells that are related to senescence instead of simply the passing of chronological time. We investigated two populations of the longest living non-colonial metazoan, Arctica islandica, with lifespans that differed sixfolds. Of four investigated parameters (nucleic acid oxidation, protein oxidation, lipid oxidation, and protein instability), only nucleic acid oxidation increased with age and correl...

  11. Arctocypris fuhrmanni, n. gen., n. sp. (Crustacea, Ostracoda, Eucypridinae) from Spitsbergen (Norway).

    Science.gov (United States)

    Petkovski, Trajan K; Scharf, Burkhard; Keyser, Dietmar

    2016-01-14

    Material from Spitsbergen (Norway) collected by Spitzenberger (1996) was reinvestigated. A new genus Arctocypris and a new species Arctocypris. fuhrmanni n. gen. n. sp. are described in the present paper. A key to the genera of the subfamily Eucypridinae is provided. At the moment Arctocypris n. gen. comprises four species: Arctocypris arctica (Olofsson, 1918) comb. nov.; A. dulcifons (Diebel & Pietrzeniuk, 1969) comb. nov.; A. foveata (Delorme, 1968) comb. nov. and Arctocypris fuhrmanni n. gen., n. sp.

  12. Preparation and characterization of κ-carrageenase immobilized onto magnetic iron oxide nanoparticles

    OpenAIRE

    Anfeng Xiao; Caiyun Xu; Yan Lin; Hui Ni; Yanbing Zhu; Huinong Cai

    2016-01-01

    Background: Carboxyl-functionalized magnetic nanoparticles were synthesized via chemical co-precipitation method and modified with oleic acid which was oxidized by potassium permanganate, and κ-carrageenase from Pseudoalteromonas sp. ASY5 was subsequently immobilized onto them. The immobilization conditions were further optimized, and the characterizations of the immobilized κ-carrageenase were investigated. Results: The κ-carrageenase was immobilized onto magnetic iron oxide nanoparticles...

  13. Toxicity of Bioactive and Probiotic Marine Bacteria and Their Secondary Metabolites in Artemia sp. and Caenorhabditis elegans as Eukaryotic Model Organisms

    Science.gov (United States)

    Neu, Anna Katrin; Månsson, Maria; Prol-García, María J.

    2014-01-01

    We have previously reported that some strains belonging to the marine Actinobacteria class, the Pseudoalteromonas genus, the Roseobacter clade, and the Photobacteriaceae and Vibrionaceae families produce both antibacterial and antivirulence compounds, and these organisms are interesting from an applied point of view as fish probiotics or as a source of pharmaceutical compounds. The application of either organisms or compounds requires that they do not cause any side effects, such as toxicity in eukaryotic organisms. The purpose of this study was to determine whether these bacteria or their compounds have any toxic side effects in the eukaryotic organisms Artemia sp. and Caenorhabditis elegans. Arthrobacter davidanieli WX-11, Pseudoalteromonas luteoviolacea S4060, P. piscicida S2049, P. rubra S2471, Photobacterium halotolerans S2753, and Vibrio coralliilyticus S2052 were lethal to either or both model eukaryotes. The toxicity of P. luteoviolacea S4060 could be related to the production of the antibacterial compound pentabromopseudilin, while the adverse effect observed in the presence of P. halotolerans S2753 and V. coralliilyticus S2052 could not be explained by the production of holomycin nor andrimid, the respective antibiotic compounds in these organisms. In contrast, the tropodithietic acid (TDA)-producing bacteria Phaeobacter inhibens DSM17395 and Ruegeria mobilis F1926 and TDA itself had no adverse effect on the target organisms. These results reaffirm TDA-producing Roseobacter bacteria as a promising group to be used as probiotics in aquaculture, whereas Actinobacteria, Pseudoalteromonas, Photobacteriaceae, and Vibrionaceae should be used with caution. PMID:24141121

  14. Composition, Buoyancy Regulation and Fate of Ice Algal Aggregates in the Central Arctic Ocean

    DEFF Research Database (Denmark)

    Fernandez-Mendez, Mar; Wenzhöfer, Frank; Peeken, Ilka

    2014-01-01

    Sea-ice diatoms are known to accumulate in large aggregates in and under sea ice and in melt ponds. There is recent evidence from the Arctic that such aggregates can contribute substantially to particle export when sinking from the ice. The role and regulation of microbial aggregation in the highly...... Arctic Ocean. Spherical aggregates densely packed with pennate diatoms, as well as filamentous aggregates formed by Melosira arctica showed sign of different stages of degradation and physiological stoichiometries, with carbon to chlorophyll a ratios ranging from 110 to 66700, and carbon to nitrogen...

  15. The marine epilithic diatom Melosira brandinii sp. nov. (Bacillariophyta from Elephant Island, Antarctic Peninsula, with comments on some related species

    Directory of Open Access Journals (Sweden)

    Luciano F. Fernandes

    2001-01-01

    Full Text Available A new species of epilithic diatom is described from samples collected near Elephant Island, Antarctic Peninsula. The cells of Melosira brandinii sp. nov. are joined in filamentous chains and attached by means of long mucilaginous stalks. The valves are circular with the valvar surface composed of irregularly arranged pentagonal Ioculi. Each loculus bears 6-12 pores on the external surface, opening to the innerside through rotae. The corona is only composed of coarse granules. A mantle is well developed, presenting rimoportulae and bearing coarse granules, which are more concentrated at the mantle edge. Comparisons with the related species Melosira arctica, M. moniliformis and M. nummuloides are made. Additionally, photomicrographs of M. arctica from the type material and Barents Sea, and of M. moniliformis from estuaries of Southern Brazil are included.Uma nova espécie de diatomácea eplítica é descrita sob microscopia eletrônica, a partir de amostras coletadas próximo à Ilha Elefante, Península Antártica. As células de Melosira brandinii sp. nov. encontram-se reunidas em cadeias filamentosas através de longos tubos mucilaginosos. As valvas são circulares, com superfície valvar provida de lóculos pentagonais arranjados irregularmente. Cada lóculo possui 6-12 poros na superfície externa, abrindo-se para o interior através de aréolas do tipo rota. A corona é composta exclusivamente por grânulos grosseiros, os quais estão mais concentrados na borda do manto. Comparações com as espécies próximas Melosira arctica, M. moniliformis e M. nummuloides foram realizadas. Adicionalmente, são fornecidas fotomicrografias de M. arctica provenientes do material tipo e do Mar de Barents (Ártico, e de M. moniliformis de estuários do Sul do Brasil.

  16. Variability in surface water properties of the southeastern South Atlantic Ocean related to the Miocene Cooling Events, evidence from calcareous dinoflagellate cysts.

    Science.gov (United States)

    Heinrich, S.; Zonneveld, K. A. F.; Willems, H.

    2009-04-01

    The middle- and upper Miocene represent major climatic shifts to colder global temperatures. These periods of cooling (Mi-Events) were characterized by oxygen isotopic shifts that have been related to size changes of the Antarctic and Arctic ice-sheets (e.g. Miller et al., 1991, St. John, 2008). The start and development of the Antarctic Circumpolar Current (ACC) during this time-interval is of major interest, as it changed the atmospheric and oceanic circulation pattern which led to the initiation of upwelling off the south western African coast (Paulsen et al., 2007). However, the complex interaction between the initiation and development of the upwelling in the western South Atlantic and its interaction with the evolution of the Antarctic Circumpolar Current as well as the built-up of the Antarctic ice-sheet is far from being fully understood. We want to improve the understanding of these processes by establishing a detailed palaeoceanographic reconstruction of the southeastern South Atlantic Ocean on the basis of calcareous dinoflagellate cyst associations. Within this study 53 samples were taken from sediment core ODP 175 1085A off the coast of Namibia and investigated by defining the calcareous dinoflagellate cyst assemblage. The general cooling trend during the middle- and upper Miocene is clearly reflected in the dinocyst record by the decrease of species adapted to warm water conditions (Calciodinellum albatrosianum and Thoracosphaera heimii) and the appearance and increase of Caracomia arctica after ~ 11.1 Ma. C. arctica is a cold water species which today is only present south of the polar front. The concentration of C. arctica varies with a cyclicity of about 200-400 kyrs which reflects an eccentricity signal. We assume that observed changes in association such as the appearance of C. arctica can either be related to the initiation of the upwelling activity in the region, which is suggested to occur at ~11.6 Ma (Paulsen & Bickert 2007), or might be the

  17. Using bacterial extract along with differential gene expression in Acropora millepora larvae to decouple the processes of attachment and metamorphosis.

    Directory of Open Access Journals (Sweden)

    Nachshon Siboni

    Full Text Available Biofilms of the bacterium Pseudoalteromonas induce metamorphosis of acroporid coral larvae. The bacterial metabolite tetrabromopyrrole (TBP, isolated from an extract of Pseudoalteromonas sp. associated with the crustose coralline alga (CCA Neogoniolithon fosliei, induced coral larval metamorphosis (100% with little or no attachment (0-2%. To better understand the molecular events and mechanisms underpinning the induction of Acropora millepora larval metamorphosis, including cell proliferation, apoptosis, differentiation, migration, adhesion and biomineralisation, two novel coral gene expression assays were implemented. These involved the use of reverse-transcriptase quantitative PCR (RT-qPCR and employed 47 genes of interest (GOI, selected based on putative roles in the processes of settlement and metamorphosis. Substantial differences in transcriptomic responses of GOI were detected following incubation of A. millepora larvae with a threshold concentration and 10-fold elevated concentration of TBP-containing extracts of Pseudoalteromonas sp. The notable and relatively abrupt changes of the larval body structure during metamorphosis correlated, at the molecular level, with significant differences (p<0.05 in gene expression profiles of 24 GOI, 12 hours post exposure. Fourteen of those GOI also presented differences in expression (p<0.05 following exposure to the threshold concentration of bacterial TBP-containing extract. The specificity of the bacterial TBP-containing extract to induce the metamorphic stage in A. millepora larvae without attachment, using a robust, low cost, accurate, ecologically relevant and highly reproducible RT-qPCR assay, allowed partially decoupling of the transcriptomic processes of attachment and metamorphosis. The bacterial TBP-containing extract provided a unique opportunity to monitor the regulation of genes exclusively involved in the process of metamorphosis, contrasting previous gene expression studies that

  18. Bacterial succession during curing process of a skate (Dipturus batis) and isolation of novel strains.

    Science.gov (United States)

    Reynisson, E; Thornór Marteinsson, V; Jónsdóttir, R; Magnússon, S H; Hreggvidsson, G O

    2012-08-01

    To study the succession of cultivated and uncultivated microbes during the traditional curing process of skate. The microbial diversity was evaluated by sequencing 16Sr RNA clone libraries and cultivation in variety of media from skate samples taken periodically during a 9-day curing process. A pH shift was observed (pH 6·64-9·27) with increasing trimethylamine (2·6 up to 75·6 mg N per 100 g) and total volatile nitrogen (TVN) (from 58·5 to 705·8 mg N per 100 g) but with relatively slow bacterial growth. Uncured skate was dominated by Oceanisphaera and Pseudoalteromonas genera but was substituted after curing by Photobacterium and Aliivibrio in the flesh and Pseudomonas on the skin. Almost 50% of the clone library is derived from putative undiscovered species. Cultivation and enrichment strategies resulted in isolation of putatively new species belonging to the genera Idiomarina, Rheinheimera, Oceanisphaera, Providencia and Pseudomonas. The most abundant genera able to hydrolyse urea to ammonia were Oceanisphaera, Psychrobacter, Pseudoalteromonas and isolates within the Pseudomonas genus. The curing process of skate is controlled and achieved by a dynamic bacterial community where the key players belong to Oceanisphaera, Pseudoalteromonas, Photobacterium, Aliivibrio and Pseudomonas. For the first time, the bacterial population developments in the curing process of skate are presented and demonstrate a reservoir of many yet undiscovered bacterial species. No Claim to Norwegian Government works Journal of Applied Microbiology © 2012 The Society for Applied Microbiology.

  19. Gene expression changes governing extreme dehydration tolerance in an Antarctic insect

    Science.gov (United States)

    Teets, Nicholas M.; Peyton, Justin T.; Colinet, Herve; Renault, David; Kelley, Joanna L.; Kawarasaki, Yuta; Lee, Richard E.; Denlinger, David L.

    2012-01-01

    Among terrestrial organisms, arthropods are especially susceptible to dehydration, given their small body size and high surface area to volume ratio. This challenge is particularly acute for polar arthropods that face near-constant desiccating conditions, as water is frozen and thus unavailable for much of the year. The molecular mechanisms that govern extreme dehydration tolerance in insects remain largely undefined. In this study, we used RNA sequencing to quantify transcriptional mechanisms of extreme dehydration tolerance in the Antarctic midge, Belgica antarctica, the world’s southernmost insect and only insect endemic to Antarctica. Larvae of B. antarctica are remarkably tolerant of dehydration, surviving losses up to 70% of their body water. Gene expression changes in response to dehydration indicated up-regulation of cellular recycling pathways including the ubiquitin-mediated proteasome and autophagy, with concurrent down-regulation of genes involved in general metabolism and ATP production. Metabolomics results revealed shifts in metabolite pools that correlated closely with changes in gene expression, indicating that coordinated changes in gene expression and metabolism are a critical component of the dehydration response. Finally, using comparative genomics, we compared our gene expression results with a transcriptomic dataset for the Arctic collembolan, Megaphorura arctica. Although B. antarctica and M. arctica are adapted to similar environments, our analysis indicated very little overlap in expression profiles between these two arthropods. Whereas several orthologous genes showed similar expression patterns, transcriptional changes were largely species specific, indicating these polar arthropods have developed distinct transcriptional mechanisms to cope with similar desiccating conditions. PMID:23197828

  20. Dicty_cDB: Contig-U13331-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available 49581 ) apolipoprotein D - mouse &X82648_1(X82648|pid:no... 60 1e-07 CP000377_2186( CP000377 |pid:none) Sili...qqf*vvllmpiihskdifqkefmplnhfiqksmwvngmklh vythilkriwiklqqniqlikmvq*qwlivdtiikrkrekmqkvllil*martkec*ksl slvhf... 49188 ... 144 4e-33 CP000388_576( CP000388 |pid:none) Pseudoalteromonas atlantica T6c,... 144 4e-33 CP00161... ) 1095456032575 Global-Ocean-Sampling_GS-26-01-01-1... 44 7.7 1 ( EI732049 ) CHORI51415M14TR BAC library from the primary bre...to EcoRI BAC Library Solanum lycopersi... 46 2.0 1 ( DN783588 ) 92317449 Sea Urchin primar

  1. Dicty_cDB: Contig-U12133-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available tr... 111 5e-23 I53078( I53078 ) homeotic gene regulator - mouse (fr...013266 |pid:none) Mus musculus 10, 11 days embryo wh... 136 1e-30 JC4666( JC4666 )lymphocyte specific helicase - mouse...NA clone MGC:... 113 1e-23 CP000388_2581( CP000388 |pid:none) Pseudoalteromonas atlantica T6c... 113 1e-23 C... clone CH211-229G3. 50 0.21 1 ( DJ025872 ) Genome-wide DNA marker of Saccharomyces cere...tauri strain OTTH05... 149 3e-34 CP000582_272( CP000582 |pid:none) Ostreococcus lucimarinus CCE9901... 148 4

  2. Genome mining reveals unlocked bioactive potential of marine Gram-negative bacteria

    DEFF Research Database (Denmark)

    Machado, Henrique; Sonnenschein, Eva; Melchiorsen, Jette

    2015-01-01

    and Pseudoalteromonadaceae families. A very high potential was identified in pigmented pseudoalteromonads with up to 20 clusters in a single strain, mostly NRPSs and NRPS-PKS hybrids. Furthermore, regulatory elements in bioactivity-related pathways including chitin metabolism, quorum sensing and iron scavenging systems were...... and Pseudoalteromonas species that commonly live in close association with eukaryotic organisms in the environment. Chitin regulation by the ChiS histidine-kinase seems to be a general trait of the Vibrionaceae family, however it is absent in the Pseudomonadaceae. Hence, the degree to which chitin influences secondary...

  3. Screening and dereplication of microbial natural products extracts

    DEFF Research Database (Denmark)

    Månsson, Maria; Vynne, Nikolaj Grønnegaard; Wietz, Matthias

    . The chemical profile could be linked to a bioactivity profile using E-SPE,3 which through the use of three different ion-exchangers and a size-exclusion column gives information about the charge, size, and polarity of active components in an extract. This can be used to discriminate between possible candidates...... expedition,1 we use a combination of chemical profiling2 and explorative solid-phase extraction (E-SPE)3 to assess the bacteria’s potential to produce new and interesting molecules. We found the use of chemical profiling by LC-UV/MS very useful for marine bacteria such as Vibrio4 and Pseudoalteromonas.5...

  4. [Comparative study of microbial communities from cultured and natural population of the mussel Mytilus trossulus in Peter the Great bay].

    Science.gov (United States)

    Beleneva, I A; Zhukova, N V; Maslennikova, E F

    2003-01-01

    The 525 strains of heterotrophic bacteria isolated from natural and cultured populations of the mussel Mytilus trossulus and the surrounding seawater were identified to a genus level on the basis of phenotypic analysis and the fatty acid composition of cell lipids. Gram-negative isolates were dominated by six genera of the family Enterobacteriaceae and by the genera Pseudoalteromonas, Vibrio, Photobacterium, Cytophaga/Flavobacterium/Bacteroides, Pseudomonas, and Moraxella, Gram-positive isolates were mainly represented by the genus Streptomyces. The taxonomic compositions of natural and cultured populations of the mussel M. trossulus in Peter the Great Bay were similar.

  5. Cloning, sequencing, and sequence analysis of two novel plasmids from the thermophilic anaerobic bacterium Anaerocellum thermophilum

    DEFF Research Database (Denmark)

    Clausen, Anders; Mikkelsen, Marie Just; Schrøder, I.

    2004-01-01

    The nucleotide sequence of two novel plasmids isolated from the extreme thermophilic anaerobic bacterium Anaerocellum thermophilum DSM6725 (A. thermophilum), growing optimally at 70degreesC, has been determined. pBAS2 was found to be a 3653 bp plasmid with a GC content of 43%, and the sequence...... revealed 10 open reading frames (ORFs). The two largest of these, namely Orf21 and Orf41, showed similarity to a Bacillus plasmid recombinase and a Pseudoalteromonas plasmid replication protein, respectively. A sequence with homology to double stranded replication origins from rolling circle plasmids...

  6. Genetic diversity of the causative agent of ice-ice disease of the seaweed Kappaphycus alvarezii from Karimunjawa island, Indonesia

    Science.gov (United States)

    Syafitri, E.; Prayitno, S. B.; Ma'ruf, W. F.; Radjasa, O. K.

    2017-02-01

    An essential step in investigating the bacterial role in the occurrence of diseases in Kappaphycus alvarezii is the characterization of bacteria associated with this seaweed. A molecular characterization was conducted on the genetic diversity of the causative agents of ice-ice disease associated with K. alvarezii widely known as the main source of kappa carrageenan. K. alvrezii infected with ice-ice were collected from the Karimunjawa island, North Java Sea, Indonesia. Using Zobell 2216E marine agar medium, nine bacterial species were isolated from the infected seaweed. The molecular characterizations revealed that the isolated bacteria causing ice-ice disease were closely related to the genera of Alteromonas, Bacillus, Pseudomonas, Pseudoalteromonas, Glaciecola, Aurantimonas, and Rhodococcus. In order to identify the symptoms causative organisms, the isolated bacterial species were cultured and were evaluated for their pathogenity. Out of 9 species, only 3 isolates were able to cause the ice-ice symptoms and consisted of Alteromonas macleodii, Pseudoalteromonas issachenkonii and Aurantimonas coralicida. A. macleodii showed the highest pathogenity.

  7. Molecular cloning, characterization and enzymatic properties of a novel βeta-agarase from a marine isolate Psudoalteromonas sp. AG52

    Directory of Open Access Journals (Sweden)

    Chulhong Oh

    2010-12-01

    Full Text Available An agar-degrading Pseudoalteromonas sp. AG52 bacterial strain was identified from the red seaweed Gelidium amansii collected from Jeju Island, Korea. A β-agarase gene which has 96.8% nucleotide identity to Aeromonas β-agarase was cloned from this strain, and was designated as agaA. The coding region is 870 bp, encoding 290 amino acids and possesses characteristic features of the glycoside hydrolase family (GHF-16. The predicted molecular mass of the mature protein was 32 kDa. The recombinant β-agarase (rAgaA was overexpressed in Escherichia coli and purified as a fusion protein. The optimal temperature and pH for activity were 55 ºC and 5.5, respectively. The enzyme had a specific activity of 105.1 and 79.5 unit/mg toward agar and agarose, respectively. The pattern of agar hydrolysis demonstrated that the enzyme is an endo-type β-agarase, producing neoagarohexaose and neoagarotetraose as the final main products. Since, Pseudoalteromonas sp. AG52 encodes an agaA gene, which has greater identity to Aeromonas β-agarase, the enzyme could be considered as novel, with its unique bio chemical characteristics. Altogether, the purified rAgaA has potential for use in industrial applications such as development of cosmetics and pharmaceuticals.

  8. Generalist hydrocarbon-degrading bacterial communities in the oil-polluted water column of the North Sea

    Science.gov (United States)

    Chronopoulou, Panagiota-Myrsini; Sanni, Gbemisola O; Silas-Olu, Daniel I; van der Meer, Jan Roelof; Timmis, Kenneth N; Brussaard, Corina P D; McGenity, Terry J

    2015-01-01

    The aim of this work was to determine the effect of light crude oil on bacterial communities during an experimental oil spill in the North Sea and in mesocosms (simulating a heavy, enclosed oil spill), and to isolate and characterize hydrocarbon-degrading bacteria from the water column. No oil-induced changes in bacterial community (3 m below the sea surface) were observed 32 h after the experimental spill at sea. In contrast, there was a decrease in the dominant SAR11 phylotype and an increase in Pseudoalteromonas spp. in the oiled mesocosms (investigated by 16S rRNA gene analysis using denaturing gradient gel electrophoresis), as a consequence of the longer incubation, closer proximity of the samples to oil, and the lack of replenishment with seawater. A total of 216 strains were isolated from hydrocarbon enrichment cultures, predominantly belonging to the genus Pseudoaltero monas; most strains grew on PAHs, branched and straight-chain alkanes, as well as many other carbon sources. No obligate hydrocarbonoclastic bacteria were isolated or detected, highlighting the potential importance of cosmopolitan marine generalists like Pseudoalteromonas spp. in degrading hydrocarbons in the water column beneath an oil slick, and revealing the susceptibility to oil pollution of SAR11, the most abundant bacterial clade in the surface ocean. PMID:25251384

  9. Isolation and identification of a bacterium from marine shrimp digestive tract: A new degrader of starch and protein

    Science.gov (United States)

    Li, Jiqiu; Tan, Beiping; Mai, Kangsen

    2011-09-01

    It is a practical approach to select candidate probiotic bacterial stains on the basis of their special traits. Production of digestive enzyme was used as a trait to select a candidate probiotic bacterial strain in this study. In order to select a bacterium with the ability to degrade both starch and protein, an ideal bacterial strain STE was isolated from marine shrimp ( Litopenaeus vannamei) intestines by using multiple selective media. The selected isolate STE was identified on the basis of its morphological, physiological, and biochemical characteristics as well as molecular analyses. Results of degradation experiments confirmed the ability of the selected isolate to degrade both starch and casein. The isolate STE was aerobic, Gram-negative, rod-shaped, motile and non-spore-forming, and had catalase and oxidase activities but no glucose fermentation activity. Among the tested carbon/nitrogen sources, only Tween40, alanyl-glycine, aspartyl-glycine, and glycyl-l-glutamic acid were utilized by the isolate STE. Results of homology comparison analyses of the 16S rDNA sequences showed that the isolate STE had a high similarity to several Pseudoalteromonas species and, in the phylogenetic tree, grouped with P. ruthenica with maximum bootstrap support (100%). In conclusion, the isolate STE was characterized as a novel strain belonging to the genus Pseudoalteromonas. This study provides a further example of a probiotic bacterial strain with specific characteristics isolated from the host gastrointestinal tract.

  10. Responses of Diverse Marine Heterotrophic Bacteria to Changing Copper Availability.

    Science.gov (United States)

    Posacka, A. M.; Maldonado, M. T.

    2016-02-01

    Copper (Cu) is essential to a variety of metabolic pathways in marine prokaryotes, including cellular respiration and degradation of complex organic substrates. Yet, its nutritional role in marine heterotrophic bacteria remains poorly understood. Our goal was to investigate the effects of Cu availability on growth and metabolism of diverse classes of marine heterotrophic bacteria (α -, Ɣ- proteobacteria and Flavobacteriia), including a number of strains isolated from the Northeast Pacific Ocean (Pseudoalteromonas sp., Alteromondales; and Dokdonia sp., Flavobacteriales) and a model bacterium from the Roseobacter clade Ruegeria pomeroyi (ATCC 700808). Our preliminary results indicate that Pseudoalteromonas sp may have a low metabolic requirement for Cu as their growth rates were only slightly reduced under Cu deficiency (10-25% µmax). In contrast, the growth of the flavobacterium Dokdonia sp is severely limited by low Cu levels (up to 90% µmax) and follows a Monod-type kinetics from 0 - 50nM Cu in EDTA-buffered media. Metabolic responses to changing Cu availability include an increase in intracellular sulfur content with decreasing Cu concentrations, while maintaining constant C:N stoichiometry. Bacterial growth efficiency (BGE, %) was directly correlated with Cu suggesting that carbon utilization in this organism is regulated by Cu availability. Our results indicate that Cu affects growth and metabolism of marine heterotrophic bacteria, and highlight the physiological differences in copper requirements among different bacterial groups.

  11. Diversity and antimicrobial activities of microbes from two Irish marine sponges, Suberites carnosus and Leucosolenia sp.

    Science.gov (United States)

    Flemer, B; Kennedy, J; Margassery, L M; Morrissey, J P; O'Gara, F; Dobson, A D W

    2012-02-01

    To evaluate the diversity and antimicrobial activity of bacteria from the marine sponges Suberites carnosus and Leucosolenia sp. Two hundred and thirty-seven bacteria were isolated from the sponges S. carnosus (Demospongiae) and Leucosolenia sp. (Calcarea). Isolates from the phyla Actinobacteria, Bacteroidetes, Firmicutes and Proteobacteria were obtained. Isolates of the genus Pseudovibrio were dominant among the bacteria from S. carnosus, whereas Pseudoalteromonas and Vibrio were the dominant genera isolated from Leucosolenia sp. Approximately 50% of the isolates from S. carnosus displayed antibacterial activity, and c. 15% of the isolates from Leucosolenia sp. demonstrated activity against the test fungal strains. The antibacterial activity observed was mostly from Pseudovibrio and Spongiobacter isolates, while the majority of the antifungal activity was observed from the Pseudoalteromonas, Bacillus and Vibrio isolates. Both sponges possess a diverse range of bioactive and potentially novel bacteria. Differences observed from the sponge-derived groups of isolates in terms of bioactivity suggest that S. carnosus isolates may be a better source of antibacterial compounds, while Leucosolenia sp. isolates appear to be a better source of antifungal compounds. This is the first study in which cultured bacterial isolates from the marine sponges S. carnosus and a Leucosolenia sp. have been evaluated for their antibacterial activity. The high percentage of antibacterial isolates from S. carnosus and of antifungal isolates from Leucosolenia sp. suggests that these two sponges may be good sources for potentially novel marine natural products. © 2011 The Authors. Journal of Applied Microbiology © 2011 The Society for Applied Microbiology.

  12. Influence of subtilisin on the adhesion of a marine bacterium which produces mainly proteins as extracellular polymers.

    Science.gov (United States)

    Leroy, C; Delbarre, C; Ghillebaert, F; Compere, C; Combes, D

    2008-09-01

    The nature of exopolymers involved in the adhesion of a marine biofilm-forming bacterium Pseudoalteromonas sp. D41 was investigated to evaluate and understand the antifouling potential of subtilisin. The exopolymers of D41 produced by fermentation were analysed by FTIR and SDS-PAGE showing the presence of polysaccharides, glycoproteins and proteins. A high content of proteins was detected both in soluble and capsular fractions. The microscopic observations of fluorescamine and calcofluor stained adhered D41 indicated mainly the presence of proteins in exopolymers produced during adhesion. Subtilisin, the broad spectrum protease, tested in natural sea water and in polystyrene microplates showed that antifouling activity was higher in the prevention of bacterial adhesion than in the detachment of adhered D41 cells. Overall, these results demonstrate the involvement of proteins in Pseudoalteromonas sp. D41 adhesion and confirm the high antifouling potential of subtilisin. This study emphasizes the major role of proteins instead of polysaccharides, thus extending our knowledge regarding the nature of extracellular polymers involved in bacterial adhesion. Furthermore, the high antifouling potential of subtilisin evaluated in the very first stages of fouling, bacterial adhesion, could lead to less toxic compounds than organometallic compounds in antifouling paint.

  13. Pseudo-proxy evaluation of climate field reconstruction methods of North Atlantic climate based on an annually resolved marine proxy network

    Science.gov (United States)

    Pyrina, Maria; Wagner, Sebastian; Zorita, Eduardo

    2017-10-01

    Two statistical methods are tested to reconstruct the interannual variations in past sea surface temperatures (SSTs) of the North Atlantic (NA) Ocean over the past millennium based on annually resolved and absolutely dated marine proxy records of the bivalve mollusk Arctica islandica. The methods are tested in a pseudo-proxy experiment (PPE) setup using state-of-the-art climate models (CMIP5 Earth system models) and reanalysis data from the COBE2 SST data set. The methods were applied in the virtual reality provided by global climate simulations and reanalysis data to reconstruct the past NA SSTs using pseudo-proxy records that mimic the statistical characteristics and network of Arctica islandica. The multivariate linear regression methods evaluated here are principal component regression and canonical correlation analysis. Differences in the skill of the climate field reconstruction (CFR) are assessed according to different calibration periods and different proxy locations within the NA basin. The choice of the climate model used as a surrogate reality in the PPE has a more profound effect on the CFR skill than the calibration period and the statistical reconstruction method. The differences between the two methods are clearer for the MPI-ESM model due to its higher spatial resolution in the NA basin. The pseudo-proxy results of the CCSM4 model are closer to the pseudo-proxy results based on the reanalysis data set COBE2. Conducting PPEs using noise-contaminated pseudo-proxies instead of noise-free pseudo-proxies is important for the evaluation of the methods, as more spatial differences in the reconstruction skill are revealed. Both methods are appropriate for the reconstruction of the temporal evolution of the NA SSTs, even though they lead to a great loss of variance away from the proxy sites. Under reasonable assumptions about the characteristics of the non-climate noise in the proxy records, our results show that the marine network of Arctica islandica can

  14. Pseudo-proxy evaluation of climate field reconstruction methods of North Atlantic climate based on an annually resolved marine proxy network

    Directory of Open Access Journals (Sweden)

    M. Pyrina

    2017-10-01

    Full Text Available Two statistical methods are tested to reconstruct the interannual variations in past sea surface temperatures (SSTs of the North Atlantic (NA Ocean over the past millennium based on annually resolved and absolutely dated marine proxy records of the bivalve mollusk Arctica islandica. The methods are tested in a pseudo-proxy experiment (PPE setup using state-of-the-art climate models (CMIP5 Earth system models and reanalysis data from the COBE2 SST data set. The methods were applied in the virtual reality provided by global climate simulations and reanalysis data to reconstruct the past NA SSTs using pseudo-proxy records that mimic the statistical characteristics and network of Arctica islandica. The multivariate linear regression methods evaluated here are principal component regression and canonical correlation analysis. Differences in the skill of the climate field reconstruction (CFR are assessed according to different calibration periods and different proxy locations within the NA basin. The choice of the climate model used as a surrogate reality in the PPE has a more profound effect on the CFR skill than the calibration period and the statistical reconstruction method. The differences between the two methods are clearer for the MPI-ESM model due to its higher spatial resolution in the NA basin. The pseudo-proxy results of the CCSM4 model are closer to the pseudo-proxy results based on the reanalysis data set COBE2. Conducting PPEs using noise-contaminated pseudo-proxies instead of noise-free pseudo-proxies is important for the evaluation of the methods, as more spatial differences in the reconstruction skill are revealed. Both methods are appropriate for the reconstruction of the temporal evolution of the NA SSTs, even though they lead to a great loss of variance away from the proxy sites. Under reasonable assumptions about the characteristics of the non-climate noise in the proxy records, our results show that the marine network of Arctica

  15. Biogenic volatile organic compound emissions along a high arctic soil moisture gradient

    DEFF Research Database (Denmark)

    Svendsen, Sarah Hagel; Lindwall, Frida; Michelsen, Anders

    2016-01-01

    emissions from a high arctic soil moisture gradient extending from dry tundra to a wet fen. Ecosystem BVOC emissions were sampled five times in the July-August period using a push-pull enclosure technique, and BVOCs trapped in absorbent cartridges were analyzed using gas chromatography-mass spectrometry....... Plant species compositions were estimated using the point intercept method. In order to take into account important underlying ecosystem processes, gross ecosystem production, ecosystem respiration and net ecosystem production were measured in connection with chamber-based BVOC measurements. Highest...... emissions of BVOCs were found from vegetation communities dominated by Salix arctica and Cassiope tetragona, which had emission profiles dominated by isoprene and monoterpenes, respectively. These results show that emissions of BVOCs are highly dependent on the plant cover supported by the varying soil...

  16. Summer C Fixation of Salix arctic is Altered by Prior Winter Snow Regimes: Photosynthetic Responses to Long-Term Snow Increases in the High Arctic of NW Greenland

    Science.gov (United States)

    Leffler, A.; Welker, J. M.; Sullivan, P. F.; Maseyk, K. S.

    2012-12-01

    Climate models and snow measurements on Greenland show increased precipitation in addition to warming in the High Arctic. Because polar semi-deserts may be water limited, additional snow and snow melt water, may alleviate mid-summer drought and promote additional carbon fixation. We investigated the long-term (10 years of experimental snow increases) consequences of additional winter snow as it effects subsequent summer gas exchange of Salix arctica in a polar semi-desert tundra ecosystem in NW Greenland (76.6N, 68.6W). In 2011, measurements of gas exchange physiology were conducted along a transect from high to ambient snow accumulation in mid-July. In 2012, gas exchange was measured in high and ambient snow zones between late June and early August. In 2012, the seasonal patterns of δ18O of xylem water and soil water between 5 and 20 cm below the soil surface was measured to determine if snow accumulation influences the water sources and depth of water used by S. arctica. In 2011, photosynthesis in the deep snow zones was lower than in the ambient snow zone; similar results were observed for leaf N content. Carbon isotope composition (δ13C) of S. arctica leaves did not differ between deep and ambient snow zones suggesting a similar season-long relationship between photosynthesis and stomatal conductance in both locations. In 2012, there was a trend towards higher photosynthesis at the height of the growing season in the deep snow zones. Light response curves in 2012 suggest higher maximum photosynthesis in the deep snow zones compared to the ambient zones. Regardless of prior winter snow accumulation, S. arctica appears to derive nearly all its xylem water from the top 5 cm of the soil. There is little evidence that differences in photosynthetic physiology result directly from increased soil moisture associated with high snow, rather the effect appears more complex. Much of the increased snow accumulation will run-off of these systems when the soils are still

  17. Palaeoecology of Holocene peat deposits from Nordvestø, north-west Greenland

    DEFF Research Database (Denmark)

    Bennike, Ole; Goodsite, Michael Evan; Heinemeier, Jan

    2008-01-01

    Two extensive peat deposits on Nordvestø, between Greenland and Canada, were examined for macroscopic remains of plants and animals. One of the peat deposits accumulated during the period from c. 7,100 to 5,100 cal. years BP. This peat is guanogenic and completely dominated by the coprophilous...... bryophyte Aplodon wormskioldii, and also contains frequent remains of feathers. The peat formed close to a large former sea bird colony, probably a puffin (Fratercula arctica) colony. Puffins are now rare in the region, but the population may have been larger during the mid Holocene, when the sea was ice......-free for a longer period than at present. The other peat deposit is dated to c. 9,300-7,400 cal. years BP, it is minerogenic and the macrofossils reflect deposition in a shallow, richly vegetated pond. This peat formed during warmer summers than at present....

  18. Medusae, siphonophores and ctenophores of the Magellan Region

    Directory of Open Access Journals (Sweden)

    Francesc Pagès

    1999-12-01

    Full Text Available Medusae, siphonophores and ctenophores were conspicuous and relatively abundant organisms in the Magellan Straits, Beagle Channel and adjacent waters during the Victor Hensen campaign in 1994. Hydromedusae were the most abundant component of this assemblage (mainly Bougainvillia macloviana, Clytia simplex and Obelia spp. and showed the highest number of species (29. Siphonophores were second in species number (8 and mainly occurred outside the Magellan Straits (mainly Muggiaea atlantica, Dimophyes arctica, Lensia conoidea and Pyrostephos vanhoeffeni. Callianira Antarctica was the only mesozooplanktonic ctenophore and showed a widespread distribution throughout the region. Aggregations of large Beroe cucumis and Desmonema gaudichaudi were observed at some stations. The abundance and depth distribution is given for the most important species and some patterns in the species distribution are postulated.

  19. Holocene stratigraphy and vegetation history in the Scoresby Sund area, East Greenland

    DEFF Research Database (Denmark)

    Funder, Svend Visby

    1978-01-01

    The Holocene stratigraphy in Scoresby Sund is based on climatic change as reflected by fluctuations in fjord and valley glaciers, immigration and extinction of marine molluscs, and the vegetation history recorded in pollen diagrams from five lakes. The histories are dated by C-14, and indirectly...... into the area, and in the period until 5000 yr BP dense dwarf shrub heath grew in areaS where it is now absent. In the fjords the subarctic Mytilus edulis and Pecten islandica lived, suggesting a climate warmer than the present. From c. 5000 yr BP the dense dwarf shrub heath began to disappear in the coastal...... areas, and a 'poor' heath dominated by the high arctic Salix Arctica and Cassiope tetragona expanded. These two species, which are now extremely common, apparently did not grow in the area until c. 6000 yrBP. In lakes in the coastal area minerogenic sedimentation at c. 2800 yr BP, reflecting the general...

  20. Renaissance bookbindings on Slovene reformation prints from the Slovene National Museum in Ljubljana

    Directory of Open Access Journals (Sweden)

    Sonja Svoljšak

    2004-01-01

    Full Text Available Four of these prints: two Dalmatin’s Bibles, Dalmatin’s Lepe karszhanske molitve and Trubar’s Hishna postilla have leather stiff board decorative renaissance bindings while Bohorič’s Arcticae horulae succisivae has a stiff board vellum binding.A short overview of the European renaissance bookbindnig characteristics and decorative motives development is presented in the first part, followed by the codicological census. The second part of the research consists of decorative tools and motives clasiffication and an individual motive analysis. An overview of the decorative motives on four decorative reformation bindings in the context of the European reformation book decoration styles with special emphasis on the Wittemberg reformation book decoration style is given in the final analysis.

  1. Taxonomic revision of deep-sea Ostracoda from the Arctic Ocean

    Science.gov (United States)

    Yasuhara, Moriaki; Stepanova, Anna; Okahashi, Hisayo; Cronin, Thomas M.; Brouwers, Elisabeth M.

    2015-01-01

    Taxonomic revision of deep-sea Ostracoda from the Arctic Ocean was conducted to reduce taxonomic uncertainty that will improve our understanding of species ecology, biogeography and relationship to faunas from other deep-sea regions. Fifteen genera and 40 species were examined and (re-)illustrated with high-resolution scanning electron microscopy images, covering most of known deep-sea species in the central Arctic Ocean. Seven new species are described: Bythoceratina lomonosovensis n. sp., Cytheropteron parahamatum n. sp., Cytheropteron lanceae n. sp.,Cytheropteron irizukii n. sp., Pedicythere arctica n. sp., Cluthiawhatleyi n. sp., Krithe hunti n. sp. This study provides a robust taxonomic baseline for application to paleoceanographical reconstruction and biodiversity analyses in this climatically sensitive region.

  2. Does warming affect growth rate and biomass production of shrubs in the High Arctic?

    DEFF Research Database (Denmark)

    Campioli, Matteo; Schmidt, Niels Martin; Albert, Kristian Rost

    2013-01-01

    (for RGR and branching) and gas exchange and chemical analysis (for GEP and C concentration). Warming nearly doubled the apical RGR of Cassiope, whereas it did not affect the apical RGR of Salix. Similarly, secondary growth increased for Cassiope but not for Salix. In particular, warming enhanced......Few studies have assessed directly the impact of warming on plant growth and biomass production in the High Arctic. Here, we aimed to investigate the impact of 7 years of warming (open greenhouses) on the aboveground relative growth rate (RGR) of Cassiope tetragona and Salix arctica in North......-Eastern Greenland. RGR was assessed for apical (leaves, stem, reproductive organs) and lateral meristems (secondary growth of stem and branches) and accompanied by measures of gross ecosystem production (GEP), branching and tissue carbon (C) concentration. Measurements were based on harvest and biometric methods...

  3. Structure of sediments of the final stage of the Kazantsevo transgression (MIS 5) in the north of Western Siberia

    Science.gov (United States)

    Gusev, E. A.; Molod'kov, A. N.

    2012-04-01

    The section of Kazanian marine sediments in the mouth of the Yenisei in the area of Ladygin Yar is studied with use of electron spin resonance analysis of shell remains of malacofauna and infrared optically stimulated luminescence analyses of grains of field spars. The results obtained fall within the interval from 77 000 to 71 000 years, which allows one to associate this strata with the final stage of the Kazanian transgression. Transgress sediments with vast boreal fauna of marine mollusks including representative species Arctica islandica accumulated during the MIS 5 period eliminate the possibility of existence of a glacial environment in the lower courses of the Yenisei and, moreover, the location of the region under the shield of ice sheet within this period.

  4. Improved UV-B screening capacity does not prevent negative effects of ambient UV irradiance on PSII performance in High Arctic plants. Results from a six year UV exclusion study

    DEFF Research Database (Denmark)

    Albert, Kristian Rost; Mikkelsen, Teis Nørgaard; Ro-Poulsen, H.

    2010-01-01

    Long-term responses of ambient solar ultraviolet (UV) radiation were investigated on Salix arctica and Vaccinium uliginosum in a High Arctic heath ecosystem in Zackenberg, northeast Greenland. Over a period of six years, UV exclusion was conducted in the growing season by means of filters: 60% UV......-B reduction, 90% UV-B + UV-A reduction, UV transparent filter control, and an open control without filter. Plant responses were evaluated using specific leaf area, leaf content of UV-B absorbing compounds and PSII performance parameters derived from chlorophyll-a fluorescence induction curves. Based...... increased TRo/ABS = FV/FM and REo/ETo. These results demonstrate the current level of ambient UV-B to decrease PSII performance significantly in these High Arctic plants. It appears that the two plant species both have improved their UV-screening capacity, but through different strategies, although this did...

  5. An Integrated Metabolomic and Genomic Mining Workflow to Uncover the Biosynthetic Potential of Bacteria

    DEFF Research Database (Denmark)

    Månsson, Maria; Vynne, Nikolaj Grønnegaard; Klitgaard, Andreas

    2016-01-01

    in bacteria and mine the associated chemical diversity. Thirteen strains closely related to Pseudoalteromonas luteoviolacea isolated from all over the Earth were analyzed using an untargeted metabolomics strategy, and metabolomic profiles were correlated with whole-genome sequences of the strains. We found...... vector machines. Features were dereplicated by tandem mass spectrometry (MS/MS) networking to identify molecular families of the same biosynthetic origin, and the associated pathways were probed using comparative genomics. Most of the discriminating features were related to antibacterial compounds......, including the thiomarinols that were reported from P. luteoviolacea here for the first time. By comparative genomics, we identified the biosynthetic cluster responsible for the production of the antibiotic indolmycin, which could not be predicted with standard methods. In conclusion, we present an efficient...

  6. Dicty_cDB: Contig-U10818-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available tr... 360 3e-97 I53078( I53078 ) homeotic gene regulator - mouse (fragment) &S681... 360 3e-97 AK160825_...8 |pid:none) Pseudoalteromonas atlantica T6c... 204 5e-52 CP000227_1715( CP000227 |pid:none) Bacillus cereus...Deinococcus deserti VCD115, comp... 218 1e-54 CP000875_1757( CP000875 |pid:none) Herpetosiphon aurantiacus A... plasm... 205 8e-51 CP000876_225( CP000876 |pid:none) Herpetosiphon aurantiacus ATCC 2... 205 8e-51 AM181176...sapiens c... 346 2e-98 CP000592_288( CP000592 |pid:none) Ostreococcus lucimarinus CCE9901... 363 2e-98 AF308

  7. Dicty_cDB: Contig-U16439-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available n DNA sequence from clone CTD-... 102 9e-20 I49011( I49011 ) gene Ube1y protein - mouse (fragment) &U...elii mRNA; cDNA DKFZp459G1... 91 3e-16 CR767821_875( CR767821 |pid:none) Ehrlichia ruminanti...inus str. NA... 70 5e-10 CP000388_1921( CP000388 |pid:none) Pseudoalteromonas atlantica...vis ubiquitin-activatin... 129 7e-28 CP000584_250( CP000584 |pid:none) Ostreococcus lucimarinus CCE9901... 1...16589 |pid:none) Uncultured Group I marine crenarch... 81 2e-13 AM920435_125( AM920435 |pid:none) Penicilliu

  8. Toxicity of Bioactive and Probiotic Marine Bacteria and Their Secondary Metabolites in Artemia sp. and Caenorhabditis elegans as Eukaryotic Model Organisms

    DEFF Research Database (Denmark)

    Neu, Anna; Månsson, Maria; Gram, Lone

    2014-01-01

    an applied point of view as fish probiotics or as a source of pharmaceutical compounds. The application of either organisms or compounds requires that they do not cause any side effects, such as toxicity in eukaryotic organisms. The purpose of this study was to determine whether these bacteria...... or their compounds have any toxic side effects in the eukaryotic organisms Artemia sp. and Caenorhabditis elegans. Arthrobacter davidanieli WX-11, Pseudoalteromonas luteoviolacea S4060, P. piscicida S2049, P. rubra S2471, Photobacterium halotolerans S2753, and Vibrio coralliilyticus S2052 were lethal to either...... of holomycin nor andrimid, the respective antibiotic compounds in these organisms. In contrast, the tropodithietic acid (TDA)-producing bacteria Phaeobacter inhibens DSM17395 and Ruegeria mobilis F1926 and TDA itself had no adverse effect on the target organisms. These results reaffirm TDA...

  9. Bioprospecting for Exopolysaccharides from Deep-Sea Hydrothermal Vent Bacteria: Relationship between Bacterial Diversity and Chemical Diversity.

    Science.gov (United States)

    Delbarre-Ladrat, Christine; Salas, Marcia Leyva; Sinquin, Corinne; Zykwinska, Agata; Colliec-Jouault, Sylvia

    2017-09-20

    Many bacteria biosynthesize structurally diverse exopolysaccharides (EPS) and excrete them into their surrounding environment. The EPS functional features have found many applications in industries such as cosmetics and pharmaceutics. In particular, some EPS produced by marine bacteria are composed of uronic acids, neutral sugars, and N-acetylhexosamines, and may also bear some functional sulfate groups. This suggests that they can share common structural features with glycosaminoglycans (GAG) like the two EPS (HE800 and GY785) originating from the deep sea. In an attempt to discover new EPS that may be promising candidates as GAG-mimetics, fifty-one marine bacterial strains originating from deep-sea hydrothermal vents were screened. The analysis of the EPS chemical structure in relation to bacterial species showed that Vibrio, Alteromonas, and Pseudoalteromonas strains were the main producers. Moreover, they produced EPS with distinct structural features, which might be useful for targeting marine bacteria that could possibly produce structurally GAG-mimetic EPS.

  10. FIRST ISOLATION OF VIBRIO PROBIOTICUS FROM THE GUT OF PORTUNUS PELAGICUS (LINNAEUS, 1758 AND ITS PROBIOTIC COMPETENCY AGAINST SHELLFISH PATHOGENS

    Directory of Open Access Journals (Sweden)

    Mhd Ikhwanuddin

    2012-09-01

    Full Text Available In this study, the Vibrio probioticus was isolated from the gut of female Portunus pleagicus, identified through 16S rDNA gene sequencing, and was evaluated for its probiotic features. The probiont was tested in co-culture assay at various concentrations against three target shellfish pathogens including V. harveyi, V. parahaemolyticus and Pseudoalteromonas piscicida. In a co-culture assay it was apparent that the V. probioticus had shown to outcompete the growth of tested pathogenic bacteria due to its antibacteriocin properties. Different ratios produced different effect on tested pathogens, however, the highest ratio (pathogen:probiont was more effective in suppressing the pathogen. A maximum inhibition growth was recorded for V. harveyi and P. piscicida. The probionts could further be tested in vivo culture environment to understand the effectiveness in microbial control of P. pelagicus larviculture and other aquaculture species.

  11. Diversity of bacteria in surface ice of Austre Lovénbreen glacier, Svalbard.

    Science.gov (United States)

    Zeng, Yin-Xin; Yan, Ming; Yu, Yong; Li, Hui-Rong; He, Jian-Feng; Sun, Kun; Zhang, Fang

    2013-05-01

    Two 16S rRNA gene clone libraries Cores 1U and 2U were constructed using two ice core samples collected from Austre Lovénbreen glacier in Svalbard. The two libraries yielded a total of 262 clones belonging to 59 phylotypes. Sequences fell into 10 major lineages of the domain Bacteria, including Proteobacteria (alpha, beta, gamma and delta subdivisions), Bacteroidetes, Actinobacteria, Firmicutes, Acidobacteria, Deinococcus-Thermus, Chloroflexi, Planctomycetes, Cyanobacteria and candidate division TM7. Among them, Bacteroidetes, Actinobacteria, Alphaproteobacteria and Cyanobacteria were most abundant. UniFrac data showed no significant differences in community composition between the two ice cores. A total of nineteen bacterial strains from the genera Pseudoalteromonas and Psychrobacter were isolated from the ice cores. Phylogenetic and phenotypic analyses revealed a close relationship between the ice core isolates and bacteria in marine environments, indicating a wide distribution of some bacterial phylotypes in both terrestrial and marine ecosystems.

  12. Evaluation of Various Metallic Coatings on Steel to Mitigate Biofilm Formation

    Directory of Open Access Journals (Sweden)

    Hajime Ikigai

    2009-02-01

    Full Text Available In marine environments and water systems, it is easy for many structures to form biofilms on their surfaces and to be deteriorated due to the corrosion caused by biofilm formation by bacteria. The authors have investigated the antibacterial effects of metallic elements in practical steels so far to solve food-related problems, using Escherichia coli and Staphylococcus aureus. However, from the viewpoint of material deterioration caused by bacteria and their antifouling measures, we should consider the biofilm behavior as aggregate rather than individual bacterium. Therefore, we picked up Pseudomonas aeruginosa and Pseudoalteromonas carageenovara in this study, since they easily form biofilms in estuarine and marine environments. We investigated what kind of metallic elements could inhibit the biofilm formation at first and then discussed how the thin films of those inhibitory elements on steels could affect biofilm formation. The information would lead to the establishment of effective antifouling measures against corrosion in estuarine and marine environments.

  13. Evaluation of various metallic coatings on steel to mitigate biofilm formation.

    Science.gov (United States)

    Kanematsu, Hideyuki; Ikigai, Hajime; Yoshitake, Michiko

    2009-02-01

    In marine environments and water systems, it is easy for many structures to form biofilms on their surfaces and to be deteriorated due to the corrosion caused by biofilm formation by bacteria. The authors have investigated the antibacterial effects of metallic elements in practical steels so far to solve food-related problems, using Escherichia coli and Staphylococcus aureus. However, from the viewpoint of material deterioration caused by bacteria and their antifouling measures, we should consider the biofilm behavior as aggregate rather than individual bacterium. Therefore, we picked up Pseudomonas aeruginosa and Pseudoalteromonas carageenovara in this study, since they easily form biofilms in estuarine and marine environments. We investigated what kind of metallic elements could inhibit the biofilm formation at first and then discussed how the thin films of those inhibitory elements on steels could affect biofilm formation. The information would lead to the establishment of effective antifouling measures against corrosion in estuarine and marine environments.

  14. Nigribactin, a Novel Siderophore from Vibrio nigripulchritudo, Modulates Staphylococcus aureus Virulence Gene Expression

    DEFF Research Database (Denmark)

    Nielsen, Anita; Månsson, Maria; Wietz, Matthias

    2012-01-01

    Staphylococcus aureus is a serious human pathogen that employs a number of virulence factors as part of its pathogenesis. The purpose of the present study was to explore marine bacteria as a source of compounds that modulate virulence gene expression in S. aureus. During the global marine Galathea...... 3 expedition, a strain collection was established comprising bacteria that express antimicrobial activity against Vibrio anguillarum and/or Staphylococcus aureus. Within this collection we searched colony material, culture supernatants, and cell extracts for virulence modulating activity showing...... that 68 out of 83 marine bacteria (affiliated with the Vibrionaceae and Pseudoalteromonas sp.) influenced expression of S. aureus hla encoding α-hemolysin toxin and/or spa encoding Protein A. The isolate that upon initial screening showed the highest degree of interference (crude ethyl acetate extract...

  15. Polysiloxane-based block copolymers with marine bacterial anti-adhesion properties.

    Science.gov (United States)

    Duong, The Hy; Briand, Jean-François; Margaillan, André; Bressy, Christine

    2015-07-22

    Di- and triblock copolymers based on tert-butyldimethylsilyl methacrylate (MASi) and poly(dimethylsiloxane) (PDMS) macro-RAFT agents were synthesized resulting in copolymers with predictable molar masses and low dispersities (Đ marine bacteria (Pseudoalteromonas sp. and Shewanella sp.) isolated from the Mediterranean Sea. Coatings based on PDMS-based block copolymers demonstrated anti-adhesive performances against the two strains better than that of the coating containing only PMASi-based polymers. Coatings based on diblock copolymers demonstrated antifouling performances in the field that were better than those of the corresponding coatings containing triblock copolymers. Results of both lab and field assays showed that the antifouling properties were related to coatings possessing the highest receding water contact angle.

  16. Oxidative cyclization of prodigiosin by an alkylglycerol monooxygenase-like enzyme

    DEFF Research Database (Denmark)

    de Rond, Tristan; Stow, Parker; Eigl, Ian

    2017-01-01

    Prodiginines, which are tripyrrole alkaloids displaying a wide array of bioactivities, occur as linear and cyclic congeners. Identification of an unclustered biosynthetic gene led to the discovery of the enzyme responsible for catalyzing the regiospecific C–H activation and cyclization of prodigi......Prodiginines, which are tripyrrole alkaloids displaying a wide array of bioactivities, occur as linear and cyclic congeners. Identification of an unclustered biosynthetic gene led to the discovery of the enzyme responsible for catalyzing the regiospecific C–H activation and cyclization...... of prodigiosin to cycloprodigiosin in Pseudoalteromonas rubra. This enzyme is related to alkylglycerol monooxygenase and unrelated to RedG, the Rieske oxygenase that produces cyclized prodiginines in Streptomyces, implying convergent evolution....

  17. Marine bacterioplankton diversity and community composition in an antarctic coastal environment.

    Science.gov (United States)

    Lo Giudice, Angelina; Caruso, Consolazione; Mangano, Santina; Bruni, Vivia; De Domenico, Maria; Michaud, Luigi

    2012-01-01

    The bacterial community inhabiting the water column at Terra Nova Bay (Ross Sea, Antarctica) was examined by the fluorescent in situ hybridization (FISH) technique and the genotypic and phenotypic characterization of 606 bacterial isolates. Overall, the FISH analysis revealed a bacterioplankton composition that was typical of Antarctic marine environments with the Cytophaga/Flavobacter (CF) group of Bacteroidetes that was equally dominant with the Actinobacteria and Gammaproteobacteria. As sampling was performed during the decay of sea-ice, it is plausible to assume the origin of Bacteroidetes from the sea-ice compartment where they probably thrive in high concentration of DOM which is efficiently remineralized to inorganic nutrients. This finding was supported by the isolation of Gelidibacter, Polaribacter, and Psychroflexus members (generally well represented in Antarctic sea-ice) which showed the ability to hydrolyze macromolecules, probably through the production of extracellular enzymes. A consistently pronounced abundance of the Gammaproteobacteria (67.8%) was also detected within the cultivable fraction. Altogether, the genera Psychromonas and Pseudoalteromonas accounted for 65.4% of total isolates and were ubiquitous, thus suggesting that they may play a key role within the analyzed bacterioplankton community. In particular, Pseudoalteromonas isolates possessed nitrate reductase and were able to hydrolyze substrates for protease, esterase, and β-galactosidase, thus indicating their involvement in the carbon and nitrogen cycling. Finally, the obtained results highlight the ability of the Actinobacteria to survive and proliferate in the Terra Nova Bay seawater as they generally showed a wide range of salt tolerance and appeared to be particularly competitive with strictly marine bacteria by better utilizing supplied carbon sources.

  18. Diversidad de bacterias cultivables de la costa de Caleta Olivia, Patagonia, Argentina

    Directory of Open Access Journals (Sweden)

    pucci graciela natalia

    2009-12-01

    Full Text Available Caleta Olivia es una ciudad que posee boyas de por donde se exporta el petróleo crudo obtenido de la zona norte de la provincia de Santa Cruz –Argentina. Este trabajo tuvo como objetivo estudiar las posibilidades de utilización microbiana de petróleo crudo e identificar las bacterias que se encuentran presentes en la costa. La mineralización de hidrocarburos se siguió por la producción de dióxido de carbono. Se tomaron muestras de agua de mar y sedimento intermarial de tres sitios. Se realizaron recuentos bacterianos en los medios de cultivo BBR, BRN medio mineral con petróleo gas oil y ENDO para bacterias coliformes. Las bacterias se identificaron utilizando el sistema de Sherlock de MIDI. Las mineralizaciones evidenciaron la capacidad existente de los microorganismos para la utilización de hidrocarburos. Los recuentos de coliformes fueron negativos. Se aislaron un total de 403 cepas a las que se les realizó la extracción de ácidos grasos e identificación, de ellas solo 172 fueron identificadas por el sistema. Se distribuyeron en 32 géneros y 50 especies bacterianas. El resto el sistema no las identificó debido a que no halló cepas similares en la base de datos del sistema. Las Pseudoalteromonas fueron el género que más se aisló. El análisis de componentes principales asocio al verano y al otoño con la mayor biodiversidad de géneros. Se encontraron representantes de los siguientes géneros Arthrobacter, Dietzia, Acinetobacter, Microbacterium, Micrococcus, Bacillus, Pseudomonas y Pseudoalteromonas. Estos microorganismos son citados en la bibliografía como degradadores de hidrocarburos.

  19. DIVERSIDAD DE BACTERIAS CULTIVABLES DE LA COSTA DE CALETA OLIVIA, PATAGONIA, ARGENTINA

    Directory of Open Access Journals (Sweden)

    GRACIELA PUCCI

    2009-01-01

    Full Text Available Caleta Olivia es una ciudad que posee boyas por donde se exporta el petróleo crudo obtenido de la zona norte de la provincia de Santa Cruz, Argentina. Este trabajo tuvo como objetivo estudiar las posibilidades de utilización microbiana de petróleo crudo y sus derivados e identificar las bacterias cultivables que se encuentran presentes en la costa de Caleta Olivia. La mineralización de hidrocarburos se detectó por la producción de dióxido de carbono. Se tomaron muestras de agua de mar y sedimento intermarial de tres sitios. Se realizaron recuentos bacterianos en los medios de cultivo BBR, BRN, medio mineral con petróleo gas oil y ENDO para bacterias coliformes. Las bacterias se identificaron utilizando el sistema de Sherlock de MIDI. Las mineralizaciones evidenciaron la capacidad existente en los microorganismos para la utilización de hidrocarburos. Los recuentos de coliformes fueron negativos. Se aislaron un total de 403 cepas a las que se les realizó la extracción de ácidos grasos e identificación, de ellas solo 172 fueron identificadas por el sistema. Se distribuyeron en 32 géneros y 50 especies bacterianas. El resto, el sistema no las identificó debido a que no halló cepas similares en la base de datos del sistema. Pseudoalteromonas fue el género que más se aisló. El análisis de componentes principales asoció al verano y al otoño con la mayor biodiversidad de géneros. Se encontraron repre- sentantes de los siguientes géneros: Arthrobacter, Dietzia, Acinetobacter, Microbacterium, Micrococcus, Bacillus, Pseudomonas y Pseudoalteromonas. Estos microorganismos son citados en la bibliografía como degradadores de hidrocarburos.

  20. Isolation of Potential Bacteria as Inoculum for Biofloc Formation in Pacific Whiteleg Shrimp, Litopenaeus vannamei Culture Ponds.

    Science.gov (United States)

    Kasan, Nor Azman; Ghazali, Nurarina Ayuni; Ikhwanuddin, Mhd; Ibrahim, Zaharah

    2017-01-01

    A new green technology to reduce environmental damages while optimizing production of Pacific Whiteleg shrimp, Litopenaeus vannamei was developed known as "Biofloc technology". Microbial communities in biofloc aggregates are responsible in eliminating water exchange and producing microbial proteins that can be used as supplemented feed for L. vannamei. This study aimed to isolate and identify potential bioflocculant-producing bacteria to be used as inoculum for rapid formation of biofloc. For the purpose of this study, bacterial communities during 0, 30 and 70 days of culture (DOC) of L. vannamei grow-out ponds were isolated and identified through phenotypic and 16S rDNA sequences analysis. Phylogenetic relationships between isolated bacteria were then evaluated through phylogenetic tree analysis. One-way analysis of variance (ANOVA) was used to compare the differences of microbial communities at each DOC. Out of 125 bacterial isolates, nine species of bacteria from biofloc were identified successfully. Those bacteria species were identified as Halomonas venusta, H. aquamarina, Vibrio parahaemolyticus, Bacillus infantis, B. cereus, B. safensis, Providencia vermicola, Nitratireductor aquimarinus and Pseudoalteromonas sp., respectively. Through phylogenetic analysis, these isolates belong to Proteobacteria and Firmicutes families under the genera of Halomonas sp., Vibrio sp., Bacillus sp., Providencia sp., Nitratireductor sp. and Pseudoalteromonas sp. In this study, bioflocculant-producing bacteria were successfully identified which are perfect candidates in forming biofloc to reduce water pollution towards a sustainable aquaculture industry. Presence of Halomonas sp. and Bacillus sp. in all stages of biofloc formation reinforces the need for new development regarding the ability of these species to be used as inoculum in forming biofloc rapidly.

  1. The antimicrobial activity of heterotrophic bacteria isolated from the marine sponge Erylus deficiens (Astrophorida, Geodiidae

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    Ana Patrícia Graça

    2015-05-01

    Full Text Available Interest in the study of marine sponges and their associated microbiome has increased both for ecological reasons and for their great biotechnological potential. In this work, heterotrophic bacteria associated with three specimens of the marine sponge Erylus deficiens, were isolated in pure culture, phylogenetically identified and screened for antimicrobial activity. The isolation of bacteria after an enrichment treatment in heterotrophic medium revealed diversity in bacterial composition with only Pseudoalteromonas being shared by two specimens. Of the 83 selected isolates, 58% belong to Proteobacteria, 23 % to Actinobacteria and 19 % to Firmicutes. Diffusion agar assays for bioactivity screening against four bacterial strains and one yeast, revealed that a high number of the isolated bacteria (68.7 % were active, particularly against Candida albicans and Vibrio anguillarum. Pseudoalteromonas, Microbacterium and Proteus were the most bioactive genera. After this preliminary screening, the bioactive strains were further evaluated in liquid assays against C. albicans, Bacillus subtilis and Escherichia coli. Filtered culture medium and acetone extracts from three and five days-old cultures were assayed. High antifungal activity against C. albicans in both aqueous and acetone extracts as well as absence of activity against B. subtilis were confirmed. Higher levels of activity were obtained with the aqueous extracts when compared to the acetone extracts and differences were also observed between the 3 and 5 day-old extracts. Furthermore, a low number of active strains was observed against E. coli. Potential presence of type-I polyketide synthases (PKS-I and nonribosomal peptide synthetases (NRPSs genes were detected in seventeen and thirty isolates, respectively. The high levels of bioactivity and the likely presence of associated genes suggest that Erylus deficiens bacteria are potential sources of novel marine bioactive compounds.

  2. Coastal seawater bacteria harbor a large reservoir of plasmid-mediated quinolone resistance determinants in Jiaozhou Bay, China.

    Science.gov (United States)

    Zhao, Jing-yi; Dang, Hongyue

    2012-07-01

    Diversity and prevalence of plasmid-mediated quinolone resistance determinants were investigated in environmental bacteria isolated from surface seawater of Jiaozhou Bay, China. Five qnr gene alleles were identified in 34 isolates by PCR amplification, including qnrA3 gene in a Shewanella algae isolate, qnrB9 gene in a Citrobacter freundii isolate, qnrD gene in 22 Proteus vulgaris isolates, qnrS1 gene in 1 Enterobacter sp. and 4 Klebsiella spp. isolates, and qnrS2 gene in 1 Pseudomonas sp. and 4 Pseudoalteromonas sp. isolates. The qnrC, aac(6')-Ib-cr, and qepA genes could not be detected in this study. The 22 qnrD-positive Proteus vulgaris isolates could be differentiated into four genotypes based on ERIC-PCR assay. The qnrS1 and qnrD genes could be transferred to Escherichia coli J53 Azi(R) or E. coli TOP10 recipient strains using conjugation or transformation methods. Among the 34 qnr-positive isolates, 30 had a single point mutation in the QRDRs of GyrA protein (Ala67Ser, Ser83Ile, or Ser83Thr), indicating that cooperation of chromosome- and plasmid-mediated resistance contributed to the spread and evolution of quinolone resistance in this coastal bay. Eighty-five percent of the isolates were also found to be resistant to ampicillin, and bla(CMY), bla(OXY), bla(SHV), and bla(TEM) genes were detected in five isolates that also harbored the qnrB9 or qnrS1 gene. Our current study is the first identification of qnrS2 gene in Pseudoalteromonas and Pseudomonas strains, and qnrD gene in Proteus vulgaris strains. High prevalence of diverse qnr genes in Jiaozhou Bay indicates that coastal seawater may serve as an important reservoir, natural source, and dissemination vehicle of quinolone resistance determinants.

  3. An annually-resolved palaeoenvironmental archive for the Eastern Boundary North Atlantic upwelling system: Sclerochronology of Glycymeris glycymeris (Bivalvia) shells from the Iberian shelf

    Science.gov (United States)

    Freitas, Pedro; Monteiro, Carlos; Butler, Paul; Reynolds, David; Richardson, Christopher; Gaspar, Miguel; Scourse, James

    2015-04-01

    The seasonally variable western Iberia upwelling system, albeit placed at a crucial climatic boundary position to record high frequency climate events, lacks well-dated high-resolution records of environmental variability. Bivalve shells provide robust high-resolution archives of oceanographic and climatic variability on timescales of decades to millennia. In particular, the North Atlantic Ocean region has recently seen several noteworthy sclerochronological and geochemical reconstructions based on bivalve shells (mainly Arctica islandica) of high frequency oceanographic and climatic conditions during the last millennium. However, due to the absence of Arctica islandica and similarly long-lived bivalves, sclerochronological palaeoenvironmental studies of southern European coastal shelf seas are scarce. In particular, none of these studies focus on reconstructing the variability of an eastern boundary upwelling system. The relatively long-lived bivalve (>100 years) Glycymeris glycymeris occurs in European and North West African coastal shelf seas and provides a valid annually resolved archive of environmental conditions during growth. Annual growth increment width series from living G. glycymeris shells, collected in 2014 on the western Iberian continental shelf (ca. 35 m water depth), were used to construct a statistically robust, ca. 70-year long absolutely-dated chronology. Sub-annually resolved (11 to 22 samples per year) oxygen stable isotope (δ18Oshell) data covering three years of shell growth, together with the direct evaluation of the time of growth mark deposition in shells collected during the autumn and winter months, were used to constrain the season of growth and to evaluate the seasonal bias of the sea-surface temperature signal preserved in the δ18Oshelldata. The growth increment width and δ18Oshell series, once robustly calibrated against modelled and instrumental oceanographic and climatic series, potentially provide novel insights into the

  4. DIVERSIDAD DE BACTERIAS CULTIVABLES DE LA COSTA DE CALETA OLIVIA, PATAGONIA, ARGENTINA Diversity Of Cultivable Bacteria From The Coast Of Caleta Olivia, Patagonia , Argentina

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    GRACIELA PUCCI

    Full Text Available Caleta Olivia es una ciudad que posee boyas por donde se exporta el petróleo crudo obtenido de la zona norte de la provincia de Santa Cruz, Argentina. Este trabajo tuvo como objetivo estudiar las posibilidades de utilización microbiana de petróleo crudo y sus derivados e identificar las bacterias cultivables que se encuentran presentes en la costa de Caleta Olivia. La mineralización de hidrocarburos se detectó por la producción de dióxido de carbono. Se tomaron muestras de agua de mar y sedimento intermarial de tres sitios. Se realizaron recuentos bacterianos en los medios de cultivo BBR, BRN, medio mineral con petróleo gas oil y ENDO para bacterias coliformes. Las bacterias se identificaron utilizando el sistema de Sherlock de MIDI. Las mineralizaciones evidenciaron la capacidad existente en los microorganismos para la utilización de hidrocarburos. Los recuentos de coliformes fueron negativos. Se aislaron un total de 403 cepas a las que se les realizó la extracción de ácidos grasos e identificación, de ellas solo 172 fueron identificadas por el sistema. Se distribuyeron en 32 géneros y 50 especies bacterianas. El resto, el sistema no las identificó debido a que no halló cepas similares en la base de datos del sistema. Pseudoalteromonas fue el género que más se aisló. El análisis de componentes principales asoció al verano y al otoño con la mayor biodiversidad de géneros. Se encontraron representantes de los siguientes géneros: Arthrobacter, Dietzia, Acinetobacter, Microbacterium, Micrococcus, Bacillus, Pseudomonas y Pseudoalteromonas. Estos microorganismos son citados en la bibliografía como degradadores de hidrocarburos.The aim of this work was to evaluate the oil utilization and identity of the bacterial strains present in the coast Intertidal sediments and marine water from Caleta Olivia city which were analyzed to determine bacterial counts. Five microcosms were designed for sediments and water sample. The

  5. Taxonomy of Navicula sensu lato (diatom collected from inland waters in Arctic Canada

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    Hiroshi Fukushima

    2012-03-01

    Full Text Available We identified 35 taxa of Navicula sensu lato in materials from inland waters at Herschel lsland, Smoking Hills, Holman, Byron Bay and Cambridge Bay while sailing across the reverse course of the Northwest Passage in July and August 1997. We found 20 taxa of Navicula, 4 of Chamaepinnularia, 2 each of Craticula and Placoneis, and 1 each taxon of Aneumatus, Caloneis, Fallacia, Naviculadicta, Parlibellus, Pinnuavis, and Sellaphora. The materials contain cosmopolitan species intermingled with subalpine or mountain species and endemic species (Table 1. Although samples were collected from inland waters, brackish or marine species (see Table 1 were mixed with fresh-water species similar to those reported from Antarctica. The occurrence of brackish-water and marine species is though to be made possible by the eolian transport of salt to inland water bodies. We propose the following seven new combinations: Chamaepinnularia soeherensis var. hassiaca, Chamaepinnularia soeherensis var. inflata, Chamaepinnularia soeherensis var. linearis, Chamaepinnularia soeherensis var. muscicola, Placoneis amphibola var. amphibola f. alaskaensis, Placoneis amphibola var. amphibola f. rectangularis, and Placoneis amphibola var. arctica.

  6. Diversity and bioprospective potential (cold-active enzymes) of cultivable marine bacteria from the subarctic glacial Fjord, Kongsfjorden.

    Science.gov (United States)

    Prasad, Sathish; Manasa, Poorna; Buddhi, Sailaja; Tirunagari, Preethi; Begum, Zareena; Rajan, Sivaraman; Shivaji, Sisinthy

    2014-02-01

    The diversity and abundance of culturable bacteria in Kongsfjorden water (15 stations) and sediments (12 stations) were studied. Viable numbers ranged between 105–106 CFU l−1 in water and 102–104 CFU g−1 in the sediments. A total of 291 and 43 bacterial isolates were retrieved from the water (KJF) and sediments (FS), respectively. Based on 16S rRNA gene sequence similarities, the KJF and FS isolates were grouped into 49 and 23 phylotypes, respectively. The KJF and FS phylotypes represented three phyla namely, Actinobacteria, Bacteroidetes, and Proteobacteria. At the genus level, Flavobacterium and Shewanella and at the species level, Pseudoaltermonas arctica and Colwellia psychrerythraea were dominant in the water and sediments, respectively. Most phylotypes were psychrotolerant with upper growth temperature limit of 25–37 °C and tolerated 0.3–2.5 M NaCl and pH values of 5.0–11.0. Majority of the phylotypes produced one or more of the extracellular hydrolytic enzymes amylase, lipase, caseinase, urease, gelatinase, and DNase at 4 and 18 °C, while none were chitinolytic. Few of the FS phylotypes exhibited extracellular activity only at 4 or 18 °C. Nine FS and 21 KJF isolates were pigmented. The predominant cellular fatty acids were unsaturated, branched, and modified fatty acids, which are unique to cold-adapted bacteria.

  7. Climate change alters leaf anatomy, but has no effects on volatile emissions from Arctic plants.

    Science.gov (United States)

    Schollert, Michelle; Kivimäenpää, Minna; Valolahti, Hanna M; Rinnan, Riikka

    2015-10-01

    Biogenic volatile organic compound (BVOC) emissions are expected to change substantially because of the rapid advancement of climate change in the Arctic. BVOC emission changes can feed back both positively and negatively on climate warming. We investigated the effects of elevated temperature and shading on BVOC emissions from arctic plant species Empetrum hermaphroditum, Cassiope tetragona, Betula nana and Salix arctica. Measurements were performed in situ in long-term field experiments in subarctic and high Arctic using a dynamic enclosure system and collection of BVOCs into adsorbent cartridges analysed by gas chromatography-mass spectrometry. In order to assess whether the treatments had resulted in anatomical adaptations, we additionally examined leaf anatomy using light microscopy and scanning electron microscopy. Against expectations based on the known temperature and light-dependency of BVOC emissions, the emissions were barely affected by the treatments. In contrast, leaf anatomy of the studied plants was significantly altered in response to the treatments, and these responses appear to differ from species found at lower latitudes. We suggest that leaf anatomical acclimation may partially explain the lacking treatment effects on BVOC emissions at plant shoot-level. However, more studies are needed to unravel why BVOC emission responses in arctic plants differ from temperate species. © 2015 The Authors. Plant, Cell & Environment published by John Wiley & Sons Ltd.

  8. PALAEOENVIRONMENTAL EVOLUTION OF THE PLIO-PLEISTOCENE MONTE MARIO SUCCESSION (ROME, ITALY INFERRED FROM OSTRACOD ASSEMBLAGES

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    COSTANZA FARANDA

    2007-11-01

    Full Text Available The whole "classical" Monte Mario succession has been recovered through the excavation of the Giovanni XXIII tunnel inside the city of Rome (Italy. The succession has been sampled from the Zanclean Monte Vaticano Fm. to the Lower Pleistocene Monte Mario Fm. Well-preserved and diversified ostracod faunas have been recovered and the ostracod assemblages have been studied using community structure analyses and statistical multivariate analyses. The Monte Vaticano Fm. has been referred to a bathyal marine environment (300-350 m of depth, the most represented genera being Krithe, Parakrithe, Bairdoppilata and Cytherella. The Monte Mario Fm. provided ostracod assemblages referable to littoral environments with Cimbaurila, Aurila, Costa, Carinocythereis, Leptocythere and Loxoconcha as dominant taxa. Within the Monte Mario Fm., three marine shallowing-up sequences have been recognised, the last two recording marginal marine conditions with shallow depths and variable salinity (dominant Cyprideis torosa. Two cold-water episodes have been recognised within the basal Monte Mario Fm. characterised by the occurrence of Arctica islandica and, within the upper level, by the presence of the northern guests Cytheropteron depressum, Bythocythere zetlandica, Paradoxostoma ensiforme and Paradoxostoma abbreviatum. 

  9. Research on dynamics of tundra ecosystems and their potential response to energy resource development. Progress report, May 1, 1978-April 30, 1979

    Energy Technology Data Exchange (ETDEWEB)

    Miller, P.C.

    1979-01-01

    The ecological effects (costs and benefits) of impacts that can be expected from the development and utilization of energy resources in the arctic. The impacts selected for study are: altered nutrient availability (nitrogen and phosphorus); altered patterns of soil water drainage; and vehicle tracks. The general ecosystem characteristics chosen to provide integrative measures of the possible ecological effects include annual primary production and the relative aboveground growth of the different species or growth forms comprising the vegetation. Plant growth forms are defined by height, leaf longevity, position of the perennating bud, and rooting pattern. The growth forms and species selected are: erect deciduous shrubs (Betula nana, Vaccinium uliginosum, Salix pulchra); erect evergreen shrubs (Ledum palustre); prostrate evergreen shrub (Vaccinium vitis-idaea); tussock graminoid (Eriophorum vaginatum); rhizomatous graminoid (Carex bigelowii, Carex aquatilis, Eriophorum angustifolium); forb (Artemisia arctica); grass (Calamagrostis or Arctagrostis); cushion moss (Dicranum sp.); Sphagnum sp.; and Polytrichum commune. Progress is reported in field and laboratory studies. The main conclusion of the research is that species respond individually in terms of nutrient and total nonstructural carbohydrates accumulation to fertilization, and that the growth forms studied are not distinctive from each other on the basis of plant nutrition or growth. The explicit mechanism for integrating and guiding this research and for extrapolating the existing data base to make quantitative predictions of the effects of perturbations is a simulation model of arctic tundra vegetation and soil processes called ARTUS (Arctic Tundra Simulator). (JGB)

  10. Low Density of Top Predators (Seabirds and Marine Mammals in the High Arctic Pack Ice

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    Claude R. Joiris

    2016-01-01

    Full Text Available The at-sea distribution of top predators, seabirds and marine mammals, was determined in the high Arctic pack ice on board the icebreaker RV Polarstern in July to September 2014. In total, 1,620 transect counts were realised, lasting 30 min each. The five most numerous seabird species represented 74% of the total of 15,150 individuals registered: kittiwake Rissa tridactyla, fulmar Fulmarus glacialis, puffin Fratercula arctica, Ross’s gull Rhodostethia rosea, and little auk Alle alle. Eight cetacean species were tallied for a total of 330 individuals, mainly white-beaked dolphin Lagenorhynchus albirostris and fin whale Balaenoptera physalus. Five pinniped species were represented by a total of 55 individuals and the polar bear Ursus maritimus was represented by 12 individuals. Four main geographical zones were identified: from Tromsø to the outer marginal ice zone (OMIZ, the Arctic pack ice (close pack ice, CPI, the end of Lomonosov Ridge off Siberia, and the route off Siberia and northern Norway. Important differences were detected between zones, both in species composition and in individual abundance. Low numbers of species and high proportion of individuals for some of them can be considered to reflect very low biodiversity. Numbers encountered in zones 2 to 4 were very low in comparison with other European Arctic seas. The observed differences showed strong patterns.

  11. Geographical patterns of seabird attendance to a research trawler along the Iberian Mediterranean coast

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    Pere Abelló

    2003-07-01

    Full Text Available The attendance of seabirds to a research trawler along the Mediterranean coast of the Iberian Peninsula was monitored during six demersal surveys (MEDITS project. Cruises were performed in late spring during the period 1994-1999. Twenty seabird species were recorded, including both breeders and migrants. The four most common species behind the boat were local breeders, namely the Balearic shearwater Puffinus mauretanicus, Cory´s shearwater Calonectris diomedea, Audouin´s gull Larus audouinii and the yellow-legged gull Larus cachinnans. Most seabirds made use of trawler discards to some extent, with the exception of the Puffin Fratercula arctica. Geographically consistent patterns were identified in the six years surveyed. Seabirds were most abundant along the eastern coast of Iberia, especially off the Ebro Delta and around the Columbretes Islands, coinciding with one of the major areas of primary productivity and one of the largest trawling fleets in the western Mediterranean. The location of the main seabird colonies also influenced the distribution of breeders.

  12. A direct estimate of poleward volume, heat and fresh water flux at 59.5°N between Greenland and Scotland

    Science.gov (United States)

    Rossby, Thomas; Reverdin, Gilles; Chafik, Leon; Søiland, Henrik

    2017-04-01

    The meridional overturning circulation (MOC) in the North Atlantic plays a major role in the transport of heat from low latitudes to high. In this study we combine recent measurements of currents from the surface to >700 m from a shipboard acoustic Doppler current profiler on the Nuka Arctica, a freighter in regular service between Greenland and Denmark with Argo profiles (to 2000 m) to estimate poleward volume, heat and freshwater flux at 59.5°N between Greenland and Scotland. For the period late 2012 to early 2016 the de-seasoned mean meridional overturning circulation reaches a 14.9±1.7 Sv maximum at the σθ = 27.55 kg m-3 isopycnal, which varies in depth from near the surface in the western Irminger Sea to 1000 m in Rockall Trough. The surface to bottom transport has a -0.44 Sv (southward) residual, which is not significantly different from zero. The total heat and fresh water fluxes across 59.5°N = 307 PW and 0.15 Sv, both with a 12% uncertainty principally due to uncertainties of the MOC. Comparing this ADCP dataset with an earlier one of comparable size from 1999-2002 (to 400 m depth only) shows strikingly similar transports in both west and east of the Reykjanes Ridge suggesting at least for these two periods 13 years apart very little difference in the strength of the MOC.

  13. Fluctuations of the Vestfonna ice margin at Brageneset, Nordaustlandet, Svalbard, after the last glacial maximum

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    Donner, J.J.

    1995-06-01

    Full Text Available Four radiocarbon datings of shells of Mya truncata and Saxicava arctica from the till of the end-moraine of the advance of Vestfonna against Brageneset, Nordaustlandet, between AD 1861 and 1899, gave ages between 8300 BP and 8700 BP. These are from the time when the ice margin had retreated from Brageneset after the last glaciation. An additional age of 7900 BP obtained for Astarteelliptica, also from the end-moraine, shows that the shells in the till represent a mixed death assemblage, as also shown by the composition of the molluscan fauna in general. By comparing the altitudes of the two pumice levels with their altitudes in other areas of Svalbard a curve for the relative uplift of Brageneset could be constructed. According to this curve the highest point of Brageneset at 46.5 m emerged at about 9200 BP, which gives a minimum age for the general deglaciation, an age in agreement with dates obtained from other parts of Nordaustlandet.

  14. Evaluation of seabirds in Newfoundland and Labrador, Canada, as hosts of influenza A viruses.

    Science.gov (United States)

    Wille, Michelle; Huang, Yanyan; Robertson, Gregory J; Ryan, Pierre; Wilhelm, Sabina I; Fifield, David; Bond, Alexander L; Granter, Alissa; Munro, Hannah; Buxton, Rachel; Jones, Ian L; Fitzsimmons, Michelle G; Burke, Chantelle; Tranquilla, Laura McFarlane; Rector, Megan; Takahashi, Linda; Kouwenberg, Amy-Lee; Storey, Anne; Walsh, Carolyn; Hedd, April; Montevecchi, William A; Runstadler, Jonathan A; Ojkic, Davor; Whitney, Hugh; Lang, Andrew S

    2014-01-01

    Influenza A viruses infect a wide range of hosts, including many species of birds. Avian influenza A virus (AIV) infection appears to be most common in Anseriformes (ducks, geese, and swans) and some Charadriiformes (shorebirds and gulls), but many other birds also serve as hosts of AIV. Here, we evaluated the role of seabirds as hosts for AIV. We tested 3,160 swab samples from 13 seabird species between May 2008 and December 2011 in Newfoundland and Labrador, Canada. We also tested 156 serum samples for evidence of previous infection of AIV in Common Murres (Uria aalge) and Atlantic Puffins (Fratercula arctica). Avian influenza A virus was detected in breeding Common Murres and nonbreeding Thick-billed Murres (Uria lomvia), and Common Murres also had high antibody prevalence (44%). From these findings, combined with other studies showing AIV infection in murres, we conclude that murres are important for the ecology of AIV. For other species (Razorbill, Alca torda; Leach's Storm-Petrel, Oceanodroma leucorhoa; Black-legged Kittiwake, Rissa tridactyla; Atlantic Puffin) with good coverage (>100 samples) we did not detect AIV. However, serology indicates infection does occur in Atlantic Puffins, with 22% antibody prevalence found. The possibility of virus spread through dense breeding colonies and the long distance movements of these hosts make a more thorough evaluation of the role for seabirds as hosts of AIV important.

  15. Influence of Environmental Changes on Physiology and Development of Polar Vascular Plants

    Science.gov (United States)

    Giełwanowska, Irena; Pastorczyk, Marta; Kellmann-Sopyła, Wioleta

    2011-01-01

    Polar vascular plants native to the Arctic and the Antarctic geobotanical zone have been growing and reproducing effectively under difficult environmental conditions, colonizing frozen ground areas formerly covered by ice. Our macroscopic observations and microscopic studies conducted by means of a light microscope (LM) and transmission electron microscope (TEM) concerning the anatomical and ultrastructural observations of vegetative and generative tissue in Cerastium arcticum, Colobanthus quitensis, Silene involucrata, plants from Caryophyllaceae and Deschampsia antarctica, Poa annua and Poa arctica, from Poaceae family. In the studies, special attention was paid to plants coming from diversity habitats where stress factors operated with clearly different intensity. In all examinations plants, differences in anatomy were considerable. In Deschampsia antarctica the adaxial epidermis of hairgrass leaves from a humid microhabitat, bulliform cells differentiated. Mesophyll was composed of cells of irregular shapes and resembled aerenchyma. The ultrastructural observations of mesophyll in all plants showed tight adherence of chloroplasts, mitochondria and peroxisomes, surface deformations of these organelles and formation of characteristic outgrowths and pocket concavities filled with cytoplasm with vesicles and organelles by chloroplasts. In reproduction biology of examined Caryophyllaceae and Poaceae plants growing in natural conditions, in the Arctic and in the Antarctic, and in a greenhouse in Olsztyn showed that this plant develops two types of bisexual flowers. Almost all ovules developed and formed seeds with a completely differentiated embryo both under natural conditions in the Arctic and the Antarctic and in a greenhouse in Olsztyn.

  16. MICROMORPHOLOGY OF ACHENES OF THE ARTEMISIA SPECIES (ANTHEMIDEAE – ASTERACEAE

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    E. V. Boyko

    2015-04-01

    Full Text Available The achene surface structures (SEM of 58 species of Artemisia and the species: Neopallasia pectinata, Ajania pallasiana, Filifolium sibiricum, Leucanthemum vulgare, Matricaria recutita, M. matricarioides, as well as two species of Chrysanthemum (C. chanetii, C. coronarium are provided. The achene surface sculpture in Artemisia is determined by the complexes of mucilage containing cells located in the exocarp. Significant variation of pericarp surface sculpture was revealed in the species with wide distribution area – A. arctica and A. furcata. It is determined that Artemisia is rather uniform in its achene surface structure. None of the distinguished types of the achene surface structure is characteristic to any particular section or subgenus. Mucilage containing cell complexes are not a character of the genus, since similar cell complexes are typical for some other taxa of the tribe Anthemideae as well. However, the details of the sculpture discovered by means of SEM are good additional characters for identification of some species or particular groups of species.

  17. From Megiser to the Slovene Orthography Guide 2001: Chapters from the History of Slovenising Classical Names

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    Matej Hriberšek

    2016-12-01

    Full Text Available The issue of Slovenising classical Greek and Latin names has long beset the Slovene language and Slovene classical philology with its related disciplines. The tradition of Slovenising classical names goes back at least to the grammar book by Adam Bohorič, Arcticae horulae, that is, over 400 years back. The Slovenisation of classical names has been, and continues to be, an intriguing topic, for much remains unresolved in this field despite many efforts; moreover, there are many differences of opinion even within classical philology itself, let alone between classical philology and other disciplines. The issue thus remains a challenge to classical philologists and related experts, as well as to Slovene Studies scholars and others. It is influenced by several factors: the existing Slovenisation rules, tradition and usage, language instinct and sensibility, analogy, and the expectations of various users, including both individuals and whole disciplines. The paper, outlining some of the most influential works and authors who have shaped this issue over time, presents the major chapters in its history.

  18. Grammars Preceding the 16th-Century Bohorič Grammar in Some European Countries Relevant to Slovenia

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    Kozma Ahačič

    2006-12-01

    Full Text Available The paper describes the grammars of European vernacular languages as possible indirect and (partly direct sources for the first grammar of the Slovene language, Arcticae Horulae Succisivae de Latinocarniolana Literatura [Free Winter Hours on Latin-Carniolian Grammar], written in 1584 by Adam Bohorič. Within this framework, the situation in the field of grammar writing is outlined for Germany (Ickelsamer, Albertus, Ölinger, Clajus, France (de Bovelles, Dubois, Drosée, Meigret, R. Estienne, de la Ramée , Pillot, Garnier, Cauchie, Italy (Alberti, Fortunio, Bembo, Corso, Dolce, Castelvetro, Ruscelli, Salviati, Giambullari, Trissino, Bohemia (Optát, Gzel, Philomates, Blahoslav, and Poland (Statorius. The grammar works of the individual authors are described in detail, put into the context of European production, and commented on from the viewpoint of their possible influence on the Bohorič grammar. Particular emphasis is placed on the German grammar by Johannes Clajus (1578, which may have served as its direct source, and on the Polish grammar by Statorius (1568, which shows similarities to the Bohorič grammar in both development and sources.

  19. Separating the effects of a habitat modifier, Modiolus modiolus and substrate properties on the associated megafauna

    Science.gov (United States)

    Ragnarsson, S. A.; Burgos, J. M.

    2012-08-01

    The effects of the habitat modification by the horse mussel Modiolus modiolus on the abundance and diversity of benthic fauna are poorly known. In this study we examined the effects of the abundance of M. modiolus, substrate properties, stone cover and spatial location on the abundance and species richness of the associated megafauna in Faxaflói Bay, Iceland. Quantitative data on the megafaunal abundances and species richness was obtained by analysis of photographs (n = 855) collected with an underwater camera system in an area characterised by dense beds of M. modiolus. The abundance of M. modiolus and substrate coarseness acted both synergistically towards increasing the abundance of the dominant epifaunal taxa (Henricia sp., Actiniaria and Alcyonium digitatum), although the effect of M. modiolus was in all cases greater compared to that of substrate type. The distribution of Arctica islandica was predominately influenced by the substrate type. Species richness was strongly positively correlated with abundance of M. modiolus and stone coverage, whereas substrate type was of less importance. M. modiolus effects on the abundance of the dominant epifaunal taxa and the species richness were largely non-linear and became rapidly asymptotic with their increasing abundance. Habitat modification by M. modiolus had profound effects on the megafaunal epibenthic community structure, even when found at relatively low abundance. We conclude that M. modiolus can have a major influence on ecosystem functioning in coastal waters.

  20. No interspecific covariation in intensities of macroparasites of reindeer, Rangifer tarandus (L.).

    Science.gov (United States)

    Nilssen, A C; Haugerud, R E; Folstad, I

    1998-09-01

    The macroparasites Cephenemyia trompe (Modeer) and Hypoderma (= Oedemagena) tarandi (L.) (Diptera: Oestridae), Linguatula arctica Riley, Haugerud and Nilssen (Pentastomida: Linguatulidae), Elaphostrongylus rangiferi Mitskevich (Nematoda: Protostrongylidae), and abomasal nematodes (Nematoda: Trichostrongylidae) were sampled in semidomestic reindeer calves (Rangifer tarandus (L.)) (ca. 8 months of age) in northern Norway in 1988 (n = 160) and 1989 (n = 191). Each parasite showed an aggregated (clumped) distribution among the hosts and fitted the negative binomial distribution. Analyses of interspecific associations in intensities showed that there was no consistent covariation among the parasites apart from a weak correlation (Kendall's tau 0.104, P = 0.007) between the 2 oestrids C. trompe and H. tarandi. This lack of covariation reveals that the parasites were distributed independently of each other, and suggests that innate host resistance is not a dominant factor that has a significant simultaneous effect on all parasites. The aggregated distribution of each parasite species is hypothesized to be caused by (1) random events and heterogeneities in host behaviour that create unequal transmission (exposure) rates, or (2) by heterogeneities in parasite specific immunocompetence among host individuals. Factors in hypothesis (1) are probably the most important at low transmission rates.

  1. Reprint of “Deep epibenthic communities in two contrasting areas of the Balearic Islands (western Mediterranean)”

    Science.gov (United States)

    Ramón, Montserrat; Abelló, Pere; Ordines, Francesc; Massutí, Enric

    2014-10-01

    Epibenthic communities were studied in two areas, off western and southern Mallorca (Balearic Islands, western Mediterranean), which differ in the oceanographic conditions and show different degrees of oligotrophy. Sampling was performed with beam trawl at two seasons (December 2009 and July 2010) and at depths between 228 and 900 m. A total of 199 taxa were identified, of which the most diverse were decapod crustaceans and fishes. Depth was the main factor structuring megafaunal assemblages. In the shelf break the shrimps Plesionika heterocarpus, P. antigai, Processa nouveli and P. canaliculata were dominant. In the upper slope, P. acanthonotus, Boreomysis arctica, Gaidropsarus biscayensis and Aristeus antennatus were the species that most contributed to the group formation, whereas in the middle slope the crustaceans P. acanthonotus and Munida tenuimana dominated. Specific abundances were relatively low everywhere. Diversity H‧ values ranged from 2.19 to 3.17, being higher in Sóller. Using species abundance data, significant differences were identified concerning both area and season in both shelf break and upper slope strata, while no significant differences were found in the middle slope stratum. The analysis of functional groups showed that both depth and area had a significant effect on their differential distribution.

  2. Shell architecture: a novel proxy for paleotemperature reconstructions?

    Science.gov (United States)

    Milano, Stefania; Nehrke, Gernot; Wanamaker, Alan D., Jr.; Witbaard, Rob; Schöne, Bernd R.

    2017-04-01

    Mollusk shells are unique high-resolution paleoenvironmental archives. Their geochemical properties, such as oxygen isotope composition (δ18Oshell) and element-to-calcium ratios, are routinely used to estimate past environmental conditions. However, the existing proxies have certain drawbacks that can affect paleoreconstruction robustness. For instance, the estimation of water temperature of brackish and near-shore environments can be biased by the interdependency of δ18Oshell from multiple environmental variables (water temperature and δ18Owater). Likely, the environmental signature can be masked by physiological processes responsible for the incorporation of trace elements into the shell. The present study evaluated the use of shell structural properties as alternative environmental proxies. The sensitivity of shell architecture at µm and nm-scale to the environment was tested. In particular, the relationship between water temperature and microstructure formation was investigated. To enable the detection of potential structural changes, the shells of the marine bivalves Cerastoderma edule and Arctica islandica were analyzed with Scanning Electron Microscopy (SEM), nanoindentation and Confocal Raman Microscopy (CRM). These techniques allow a quantitative approach to the microstructural analysis. Our results show that water temperature induces a clear response in shell microstructure. A significant alteration in the morphometric characteristics and crystallographic orientation of the structural units was observed. Our pilot study suggests that shell architecture records environmental information and it has potential to be used as novel temperature proxy in near-shore and open ocean habitats.

  3. Potential and limitation of combining terrestrial and marine growth records from Iceland

    Science.gov (United States)

    Piermattei, A.; Urbinati, C.; Tonelli, E.; Eggertsson, Ó.; Levanič, T.; Kaczka, R. J.; Andrew, C.; Schöne, B. R.; Büntgen, U.

    2017-08-01

    Seasonally formed, perennial growth increments of various organisms may possibly contain information about past environmental changes, well before instrumental measurements occurred. Such annually resolved proxy records have been mainly obtained from terrestrial archives, with a paucity of similar data originating from marine habitats. Iceland represents ideal conditions to develop both, tree ring (dendro) and bivalve shell (sclero) chronologies from adjacent sites. Here we introduce the first network of Icelandic birch (Betula pubescens Ehrh.) and rowan (Sorbus aucuparia) dendrochronologies, as well as ocean quahog (Arctica islandica L.) sclerochronologies. In order to identify the dominant external drivers of tree and shell growth, we assess the common growth trends and growth extremes within and between the terrestrial and marine records, as well as relationships of both archives with instrumental-based meteorological indices. Capturing a strong signal of June-August mean air temperature, the dendrochronologies are significantly positively correlated to each other. The sclerochronologies, however, reveal much lower growth coherency, which likely results from different sampling strategies and growth habitats. Disagreement between the dendro- and sclerochronologies possibly originates from unequal sample size, offset in the seasonal timing and rate of the growth, as well as varying sensitivities to different environmental factors. Our results emphasize the importance of considering a wide range of species and taxa to reconstruct a more complete picture of terrestrial and marine ecosystem functioning and productivity across various spatiotemporal scales.

  4. A dispersive migration in the Atlantic Puffin and its implications for migratory navigation.

    Directory of Open Access Journals (Sweden)

    Tim Guilford

    Full Text Available Navigational control of avian migration is understood, largely from the study of terrestrial birds, to depend on either genetically or culturally inherited information. By tracking the individual migrations of Atlantic Puffins, Fratercula arctica, in successive years using geolocators, we describe migratory behaviour in a pelagic seabird that is apparently incompatible with this view. Puffins do not migrate to a single overwintering area, but follow a dispersive pattern of movements changing through the non-breeding period, showing great variability in travel distances and directions. Despite this within-population variability, individuals show remarkable consistency in their own migratory routes among years. This combination of complex population dispersion and individual route fidelity cannot easily be accounted for in terms of genetic inheritance of compass instructions, or cultural inheritance of traditional routes. We suggest that a mechanism of individual exploration and acquired navigational memory may provide the dominant control over Puffin migration, and potentially some other pelagic seabirds, despite the apparently featureless nature of the ocean.

  5. Diversity and abundance of water birds in a subarctic lake during three decades

    Directory of Open Access Journals (Sweden)

    Anders Klemetsen

    2013-12-01

    Full Text Available The numbers of divers, ducks, gulls, terns and waders in the 15 km2 oligotrophic lake Takvatn, North Norway were estimated six times during 1983-2012. Systematic mapping surveys were done by boat within the first week after ice-break in June. Twenty-one species were observed over the years and 12 were regarded as breeding on the lake. Red-breasted merganser Mergus serrator was the dominant diving bird, with estimated minimum number of pairs varying from 15 to 39 among years. Black-throated diver Gavia arctica (1-3 pairs, tufted duck Aythya fuligula (2-15 pairs and common scoter Melanitta nigra (1-5 pairs bred regularly, while velvet scoter Melanitta fusca (1-2 and goldeneye Bucephala clangula (2-4 were found in some years and mallard Anas platyrhynchos (1 pair and wigeon Anas penelope (1 pair in one year. Common gull Larus canus (6-30 pairs and arctic tern Sterna paradisaea (2-35 pairs bred in all years. Common sandpiper Tringa hypoleucos (3-9 pairs and redshank Tringa totanus (1-4 pairs were regular waders. Density variations of mergansers, gulls and terns are possibly related to density variations of three-spined sticklebacks Gasterosteus aculeatus, their dominant fish prey. The water birds are important links in the food web of the lake.

  6. Masters of longevity: lessons from long-lived bivalves--a mini-review.

    Science.gov (United States)

    Philipp, Eva E R; Abele, Doris

    2010-01-01

    The individual ages of bivalve molluscs can be inferred from the age rings laid down every year in the shell, especially in species inhabiting areas with seasonal variability in environmental factors such as food supply and temperature. Animals obtained from different environmental settings can therefore be used to investigate how specific environmental factors shape the process of ageing in this animal class. Some bivalves have extraordinary long life spans. Species like the ocean quahog Arctica islandica and the freshwater pearl mussel Margaritifera margaritifera live for over hundreds of years. Few studies so far have attempted to study the process of ageing, either specifically in long-lived bivalves or generally in very long-lived species. This review summarizes the current knowledge of cellular ageing in bivalves with a focus on the antioxidant system, as well as tissue repair and metabolic capacities of extremely long-lived species. We discuss the applicability of these animals as models for different ageing theories. We recommend a focus of future research on the molecular mechanisms potentially involved in supporting longevity in these species, including evolutionary old cellular mechanisms such as autophagy and apoptosis, as well as diverse cellular repair pathways. Copyright 2009 S. Karger AG, Basel.

  7. Low Density of Top Predators (Seabirds and Marine Mammals) in the High Arctic Pack Ice

    Science.gov (United States)

    Boos, Karin; D'Hert, Diederik; Nachtsheim, Dominik A.

    2016-01-01

    The at-sea distribution of top predators, seabirds and marine mammals, was determined in the high Arctic pack ice on board the icebreaker RV Polarstern in July to September 2014. In total, 1,620 transect counts were realised, lasting 30 min each. The five most numerous seabird species represented 74% of the total of 15,150 individuals registered: kittiwake Rissa tridactyla, fulmar Fulmarus glacialis, puffin Fratercula arctica, Ross's gull Rhodostethia rosea, and little auk Alle alle. Eight cetacean species were tallied for a total of 330 individuals, mainly white-beaked dolphin Lagenorhynchus albirostris and fin whale Balaenoptera physalus. Five pinniped species were represented by a total of 55 individuals and the polar bear Ursus maritimus was represented by 12 individuals. Four main geographical zones were identified: from Tromsø to the outer marginal ice zone (OMIZ), the Arctic pack ice (close pack ice, CPI), the end of Lomonosov Ridge off Siberia, and the route off Siberia and northern Norway. Important differences were detected between zones, both in species composition and in individual abundance. Low numbers of species and high proportion of individuals for some of them can be considered to reflect very low biodiversity. Numbers encountered in zones 2 to 4 were very low in comparison with other European Arctic seas. The observed differences showed strong patterns. PMID:27777810

  8. Full-glacial upland tundra vegetation preserved under tephra in the Beringia National Park, Seward Peninsula, Alaska

    Science.gov (United States)

    Goetcheus, Victoria G.; Birks, Hilary H.

    2001-01-01

    The nature of the full-glacial vegetation of Beringia has been the subject of a great deal of investigation and debate. Here we present a reconstruction of an intact example of the full-glacial upland vegetation of part of the northern Seward Peninsula at one point in time. The area was blanketed by more than 1 m of tephra ca. 18,000 14C BP (ca. 21,500 cal. BP), and the former land-surface was preserved in the permafrost. The discovery of the land-surface provides a unique opportunity to study a fossil ecosystem preserved in situ. Macrofossils were used to reconstruct the vegetation growing at several sites on the buried land-surface. The macrofossil assemblages indicate a vegetation characterized by graminoids and forbs, with the occasional occurrence of Salix arctica. The vegetation was dominated by Kobresia myosuroides, other sedges ( Carex), and grasses, with a fine-scale mosaic related to snow accumulation and moisture availability. Overall, the vegetation was a closed, dry, herb-rich tundra-grassland with a continuous moss layer, growing on calcareous soil that was continuously supplied with loess. Nutrient renewal by loess deposition was probably responsible for the relatively fertile vegetation, and the occurrence of a continuous mat of acrocarpous mosses. Good physiognomic analogues can be suggested, but no exact modern vegetational analogues have been found, probably because the full-glacial environment and climate with loess deposition do not occur today.

  9. Sea-ice eukaryotes of the Gulf of Finland, Baltic Sea, and evidence for herbivory on weakly shade-adapted ice algae.

    Science.gov (United States)

    Majaneva, Markus; Blomster, Jaanika; Müller, Susann; Autio, Riitta; Majaneva, Sanna; Hyytiäinen, Kirsi; Nagai, Satoshi; Rintala, Janne-Markus

    2017-02-01

    To determine community composition and physiological status of early spring sea-ice organisms, we collected sea-ice, slush and under-ice water samples from the Baltic Sea. We combined light microscopy, HPLC pigment analysis and pyrosequencing, and related the biomass and physiological status of sea-ice algae with the protistan community composition in a new way in the area. In terms of biomass, centric diatoms including a distinct Melosira arctica bloom in the upper intermediate section of the fast ice, dinoflagellates, euglenoids and the cyanobacterium Aphanizomenon sp. predominated in the sea-ice sections and unidentified flagellates in the slush. Based on pigment analyses, the ice-algal communities showed no adjusted photosynthetic pigment pools throughout the sea ice, and the bottom-ice communities were not shade-adapted. The sea ice included more characteristic phototrophic taxa (49%) than did slush (18%) and under-ice water (37%). Cercozoans and ciliates were the richest taxon groups, and the differences among the communities arose mainly from the various phagotrophic protistan taxa inhabiting the communities. The presence of pheophytin a coincided with an elevated ciliate biomass and read abundance in the drift ice and with a high Eurytemora affinis read abundance in the pack ice, indicating that ciliates and Eurytemora affinis were grazing on algae. Copyright © 2016 Elsevier GmbH. All rights reserved.

  10. THE MIDWINTER WATERBIRD CENSUS FROM THE BASINS VÂLCELE, BUDEASA, BASCOV, PITEŞTI AND GOLEŞTI FROM THE ARGEŞ RIVER (JANUARY 2013

    Directory of Open Access Journals (Sweden)

    Adrian Mestecăneanu

    2013-07-01

    Full Text Available In this paper, the authors show the results of the midwinter waterbird census performed on the basins Vâlcele, Budeasa, Bascov, Piteşti and Goleşti from the ROSPA 0062 The Basins of the Argeş River. 45 bird species belonging to 12 orders were observed. Passeriformes (15 species and Anseriformes (13 species were the richest orders by the number of species. Unlike other years (when the Goleşti basin was in the first position, the biggest numbers of individuals was noted on Piteşti Basin. The local conditions of depth, surface, and speed of water for every basin determined the size of the unfrozen surface of water necessary for the waterbirds. Their numbers were determined by the anthropogenic pressure, food supply, places for rest, too. The highest Jaccard similarity was between Vâlcele and Budeasa ornitho-coenoses and the highest Bray-Curtis similarity was between Piteşti and Budeasa ornitho-coenoses. Anas platyrhynchos and Fulica atra were the eudominant species. The Anseriformes and Charadriiformes orders were overdominant and, into the Anseriformes order, Anas platyrhynchos and Aythya ferina were the overdominant species. Gavia arctica, Phalacrocorax pygmeus, Egretta alba, Cygnus cygnus, Mergus albellus and Alcedo atthis are in the Annex I of the Birds Directive.

  11. Biogeographical patterns and environmental controls of phytoplankton communities from contrasting hydrographical zones of the Labrador Sea

    Science.gov (United States)

    Fragoso, Glaucia M.; Poulton, Alex J.; Yashayaev, Igor M.; Head, Erica J. H.; Stinchcombe, Mark C.; Purdie, Duncan A.

    2016-02-01

    The Labrador Sea is an important oceanic sink for atmospheric CO2 because of intensive convective mixing during winter and extensive phytoplankton blooms that occur during spring and summer. Therefore, a broad-scale investigation of the responses of phytoplankton community composition to environmental forcing is essential for understanding planktonic food-web organisation and biogeochemical functioning in the Labrador Sea. Here, we investigated the phytoplankton community structure (>4 μm) from near surface blooms (1.2 mg chla m-3) occurred on and near the shelves in May and in offshore waters of the central Labrador Sea in June due to haline- and thermal-stratification, respectively. Sea ice-related (Fragilariopsis cylindrus and F. oceanica) and Arctic diatoms (Fossula arctica, Bacterosira bathyomphala and Thalassiosira hyalina) dominated the relatively cold (Ephemera planamembranacea and Fragilariopsis atlantica. The data presented here demonstrate that the Labrador Sea spring and early summer blooms are composed of contrasting phytoplankton communities, for which taxonomic segregation appears to be controlled by the physical and biogeochemical characteristics of the dominant water masses.

  12. Genome mining reveals unlocked bioactive potential of marine Gram-negative bacteria.

    Science.gov (United States)

    Machado, Henrique; Sonnenschein, Eva C; Melchiorsen, Jette; Gram, Lone

    2015-03-07

    Antibiotic resistance in bacteria spreads quickly, overtaking the pace at which new compounds are discovered and this emphasizes the immediate need to discover new compounds for control of infectious diseases. Terrestrial bacteria have for decades been investigated as a source of bioactive compounds leading to successful applications in pharmaceutical and biotech industries. Marine bacteria have so far not been exploited to the same extent; however, they are believed to harbor a multitude of novel bioactive chemistry. To explore this potential, genomes of 21 marine Alpha- and Gammaproteobacteria collected during the Galathea 3 expedition were sequenced and mined for natural product encoding gene clusters. Independently of genome size, bacteria of all tested genera carried a large number of clusters encoding different potential bioactivities, especially within the Vibrionaceae and Pseudoalteromonadaceae families. A very high potential was identified in pigmented pseudoalteromonads with up to 20 clusters in a single strain, mostly NRPSs and NRPS-PKS hybrids. Furthermore, regulatory elements in bioactivity-related pathways including chitin metabolism, quorum sensing and iron scavenging systems were investigated both in silico and in vitro. Genes with siderophore function were identified in 50% of the strains, however, all but one harboured the ferric-uptake-regulator gene. Genes encoding the syntethase of acylated homoserine lactones were found in Roseobacter-clade bacteria, but not in the Vibrionaceae strains and only in one Pseudoalteromonas strains. The understanding and manipulation of these elements can help in the discovery and production of new compounds never identified under regular laboratory cultivation conditions. High chitinolytic potential was demonstrated and verified for Vibrio and Pseudoalteromonas species that commonly live in close association with eukaryotic organisms in the environment. Chitin regulation by the ChiS histidine-kinase seems to be a

  13. Role of EPS, Dispersant and Nutrients on the Microbial Response and MOS Formation in the Subarctic Northeast Atlantic

    Directory of Open Access Journals (Sweden)

    Tony Gutierrez

    2017-04-01

    Full Text Available In this study we report the formation of marine oil snow (MOS, its associated microbial community, the factors influencing its formation, and the microbial response to crude oil in surface waters of the Faroe-Shetland Channel (FSC. The FSC is a subarctic region that is hydrodynamically complex located in the northeast Atlantic where oil extraction is currently occurring and where exploration is likely to expand into its deeper waters (>500 m. A major oil spill in this region may mirror the aftermath that ensued following the Deepwater Horizon (DWH blowout in the Gulf of Mexico, where the massive influx of Macondo crude oil triggered the formation of copious quantities of rapidly sinking MOS and successional blooms of opportunistic oil-degrading bacteria. In laboratory experiments, we simulated environmental conditions in sea surface waters of the FSC using water collected from this site during the winter of 2015. We demonstrated that the presence of dispersant triggers the formation of MOS, and that nutrient amendments magnify this. Illumina MiSeq sequencing revealed the enrichment on MOS of associated oil-degrading (Cycloclasticus, Thalassolituus, Marinobacter and EPS-producing (Halomonas, Pseudoalteromonas, Alteromonas bacteria, and included major representation by Psychrobacter and Cobetia with putative oil-degrading/EPS-producing qualities. The formation of marine snow, in the absence of crude oil and dispersant, in seawater amended with nutrients alone indicated that the de novo synthesis of bacterial EPS is a key factor in MOS formation, and the glycoprotein composition of the MOS aggregates confirmed that its amorphous biopolymeric matrix was of microbial (likely bacterial origin. The presence of dispersants and crude oil with/without nutrients resulted in distinct microbial responses marked by intermittent, and in some cases short-lived, blooms of opportunistic heterotrophs, principally obligate hydrocarbonoclastic (Alcanivorax

  14. The Difoprev® system in treatment of the skin of the elderly: preliminary data obtained in patients with dryness and hyperkeratosis

    Directory of Open Access Journals (Sweden)

    Aluigi L

    2014-04-01

    Full Text Available Leonardo AluigiCenter and School of Echography, Department of Internal Medicine, Maggiore Hospital, Bologna, ItalyBackground: Aging brings with it a number of structural and functional modifications of the skin and adnexa, particularly in the lower extremities, which may determine a gradual reduction in elasticity, with associated functional alterations which may determine preulcerative lesions. The aim of this study was to test the efficacy of the Difoprev® system, consisting in a sock functioning as a vehicle for microcapsules containing moisturizing agents (Pseudoalteromonas ferment extract, a glycoprotein synthesized by the bacterium, Pseudoalteromonas antarctica NF3. The system is already widely used for cutaneous treatment in cases of neuropathic diabetic foot, and in prevention/treatment of dryness and hyperkeratosis of the skin of the lower extremities in elderly persons (shin/foot.Methodology: Sixteen patients aged >70 years (group A were treated with the Difoprev® system for 8 weeks. This group was compared with 8 patients of the same age (group B who wore the same type of sock without microcapsules. Following initial assessment at the time of recruitment, the patients underwent controls at 15, 30, and 60 days to assess the degree of hydration of the skin derived from an objective evaluation of degree of keratosis according to an arbitrary scale of seriousness ranging from 1 (absent to 4 (marked. The changes were rated according to a scale ranging from 1 (no improvement to 5 (marked improvement. A comparative study of all cases was conducted by means of photographs taken as the treatment commenced and on termination of treatment.Results: Most patients treated with Difoprev® presented a reduction in the degree of keratosis of the skin (90%, of whom 15% had marked improvement, compared to the patients who wore only the sock with no microcapsules (10% with slight improvement. None of the patients undergoing Difoprev® system treatment

  15. Estudio comparativo de la estructura del bacterioplancton en aguas del Mar Argentino mediante el método de pirosecuenciación 454 tag A comparative study of bacterioplankton structure in Argentinian Sea waters by the 454 - tag pyrosequencing method

    Directory of Open Access Journals (Sweden)

    S. R. Peressutti

    2010-12-01

    Full Text Available El presente estudio brinda la primera información sobre diversidad y abundancia de las comunidades microbianas en dos ambientes del Mar Argentino obtenida mediante la técnica de pirosecuenciación tag ribosomal 454. Dentro del dominio Bacteria, se observaron más de 4 600 secuencias únicas a partir de 36 188 amplicones de tags y se identificaron 280 filotipos. Además, se detectaron cerca de 2 700 secuencias únicas a partir de más de 47 700 tags pertenecientes al dominio Archaea, lo que definió sólo 5 filotipos diferentes. La distancia de Jaccard presentó valores de 0,6 para bacterias y de 0,2 para arqueas, esto indica mayor diferencia entre las bacterias en los dos sitios. En el ambiente marino los filotipos más dominantes fueron Bacteroidetes Flavobacteriaceae, Proteobacteria Gammaproteobacteria, Proteobacteria Rhodobacteraceae y Proteobacteria Rickettsiales SAR11, mientras que en el estuario predominaron Pseudoalteromonadaceae Pseudoalteromonas, Proteobacteria Gammaproteobacteria, Proteobacteria Shewanella y Proteobacteria Rickettsiales SAR11. Los 2 filotipos de arqueas encontrados en mayor proporción fueron Archaea Euryarchaeota y Archaea Crenarchaeota. Las secuencias tag más numerosas representaron taxa caracterizados previamente, aunque también se halló un elevado número de filotipos de gran diversidad y de baja abundancia, que forman parte de la denominada "biosfera rara", aún no explorada, que pueden tener un papel ecológico crucial.The present study provides the first information about diversity and abundance of microbial communities in two environments of the Argentinian Sea by the 454 - tag pyrosequencing technique. We observed more than 4,600 unique bacterial sequences from 36,188 tag amplicons, forming 280 phylotypes. In addition, nearly 2,700 unique sequences from more than 47,700 tags identified as Archaea, defined only 5 different phylotypes. The Jaccard distance (0.6 for Bacteria and 0.2 for Archaea indicated

  16. The nature of plant growth-promoting effects of a pseudoalteromonad associated with the marine algae Laminaria japonica and linked to catalase excretion.

    Science.gov (United States)

    Dimitrieva, G Y; Crawford, R L; Yüksel, G U

    2006-05-01

    The goal of this study was to identify a marine algae-associated bacterium isolated from Laminaria japonica and investigate this microorganism's growth-promoting effects on plants. The bacterium, identified as Pseudoalteromonas porphyrae, was determined to display a biostimulatory activity for seed germination and shoot growth in several agricultural plants and also for growth in ginseng callus cell culture. This biostimulatory activity was linked to a catalase enzyme that was excreted in the maximal amount during the transition from logarithmic growth phase to stationary growth phase. In addition, selected shifts in growth temperature and medium salinity affected the amount of enzyme excreted. The purified catalase was determined to be composed of identical subunits. The catalase of interest displayed significantly higher biostimulatory activity than the catalase from bovine liver. The catalase investigated in this study is unique in that it promotes growth in and possibly contributes to stress tolerance of plants. The catalase of interest has the potential for use in treatments that aim to improve percent seed germination as well as obtaining tall shoots in a shorter time period.

  17. Compositional Similarities and Differences between Transparent Exopolymer Particles (TEP) from two Marine Bacteria and two Marine Algae: Significance to Surface Biofouling

    KAUST Repository

    Li, Sheng

    2015-06-12

    Transparent-exopolymer-particles (TEP) have been recently identified as a significant contributor to surface biofouling, such as on reverse osmosis (RO) membranes. TEP research has mainly focused on algal TEP/TEP precursors while limited investigations have been conducted on those released by bacteria. In this study, TEP/TEP precursors derived from both algae and bacteria were isolated and then characterized to investigate their similarities and/or differences using various advanced analytical techniques, thus providing a better understanding of their potential effect on biofouling. Bacterial TEP/TEP precursors were isolated from two species of marine bacteria (Pseudidiomarina homiensis and Pseudoalteromonas atlantica) while algal TEP/TEP precursors were isolated from two marine algae species (Alexandrium tamarense and Chaetoceros affinis). Results indicated that both isolated bacterial and algal TEP/TEP precursors were associated with protein-like materials, and most TEP precursors were high-molecular-weight biopolymers. Furthermore all investigated algal and bacterial TEP/TEP precursors showed a lectin-like property, which can enable them to act as a chemical conditioning layer and to agglutinate bacteria. This property may enhance surface biofouling. However, both proton nuclear magnetic resonance (NMR) spectra and the nitrogen/carbon (N/C) ratios suggested that the algal TEP/TEP precursors contained much less protein content than the bacterial TEP/TEP precursors. This difference may influence their initial deposition and further development of surface biofouling.

  18. Temporal succession in carbon incorporation from macromolecules by particle-attached bacteria in marine microcosms: Particle-attached bacteria incorporating organic carbon

    Energy Technology Data Exchange (ETDEWEB)

    Mayali, Xavier [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Stewart, Benjamin [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Mabery, Shalini [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Weber, Peter K. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-12-21

    Here, we investigated bacterial carbon assimilation from stable isotope-labelled macromolecular substrates (proteins; lipids; and two types of polysaccharides, starch and cellobiose) while attached to killed diatom detrital particles during laboratory microcosms incubated for 17 days. Using Chip-SIP (secondary ion mass spectrometry analysis of RNA microarrays), we identified generalist operational taxonomic units (OTUs) from the Gammaproteobacteria, belonging to the genera Colwellia, Glaciecola, Pseudoalteromonas and Rheinheimera, and from the Bacteroidetes, genera Owenweeksia and Maribacter, that incorporated the four tested substrates throughout the incubation period. Many of these OTUs exhibited the highest isotope incorporation relative to the others, indicating that they were likely the most active. Additional OTUs from the Gammaproteobacteria, Bacteroidetes and Alphaproteobacteria exhibited generally (but not always) lower activity and did not incorporate all tested substrates at all times, showing species succession in organic carbon incorporation. We also found evidence to suggest that both generalist and specialist OTUs changed their relative substrate incorporation over time, presumably in response to changing substrate availability as the particles aged. This pattern was demonstrated by temporal succession from relatively higher starch incorporation early in the incubations, eventually switching to higher cellobiose incorporation after 2 weeks.

  19. Fermentation Technologies for the Optimization of Marine Microbial Exopolysaccharide Production

    Science.gov (United States)

    Finore, Ilaria; Di Donato, Paola; Mastascusa, Vincenza; Nicolaus, Barbara; Poli, Annarita

    2014-01-01

    In the last decades, research has focused on the capabilities of microbes to secrete exopolysaccharides (EPS), because these polymers differ from the commercial ones derived essentially from plants or algae in their numerous valuable qualities. These biopolymers have emerged as new polymeric materials with novel and unique physical characteristics that have found extensive applications. In marine microorganisms the produced EPS provide an instrument to survive in adverse conditions: They are found to envelope the cells by allowing the entrapment of nutrients or the adhesion to solid substrates. Even if the processes of synthesis and release of exopolysaccharides request high-energy investments for the bacterium, these biopolymers permit resistance under extreme environmental conditions. Marine bacteria like Bacillus, Halomonas, Planococcus, Enterobacter, Alteromonas, Pseudoalteromonas, Vibrio, Rhodococcus, Zoogloea but also Archaea as Haloferax and Thermococcus are here described as EPS producers underlining biopolymer hyperproduction, related fermentation strategies including the effects of the chemical composition of the media, the physical parameters of the growth conditions and the genetic and predicted experimental design tools. PMID:24857960

  20. Diversidad de bacterias cultivables con capacidad de degradar hidrocarburos de la playa de Caleta Córdova, Argentina

    Directory of Open Access Journals (Sweden)

    Graciela N. Pucci

    2011-05-01

    Full Text Available En el presente trabajo se estudiaron las comunidades bacterianas aisladas de agua de mar y sedimentos intermareales de Caleta Córdova, norte de Comodoro Rivadavia, Argentina. Tres sitios fueron muestreados estacionalmente entre los años 2005 y 2006; el primer sitio fue una playa pública, el segundo sitio cerca de un puerto pesquero y el tercero cerca de una boya de toma de petróleo. Las comunidades bacterianas fueron determinadas en base a las diferencias en la composición de ácidos grasos de membrana, las bacterias fueron identificadas por medio del Sistema Sherlock MIDI, y el potencial de las comunidades para la utilización de hidrocarburos por la mineralización de gasoil, petróleo, kerosene, aceite lubricante y nafta. Las mineralizaciones evidenciaron la capacidad de los microorganismos para la degradación de hidrocarburos en dos de los sitios estudiados. Se aislaron 251 cepas de las que se lograron identificar 124 correspondientes a 24 géneros y 40 especies; la más frecuente fue Pseudoalteromonas.

  1. Lipolytic activity of Antarctic cold-adapted marine bacteria (Terra Nova Bay, Ross Sea).

    Science.gov (United States)

    Lo Giudice, A; Michaud, L; de Pascale, D; De Domenico, M; di Prisco, G; Fani, R; Bruni, V

    2006-11-01

    The aim of this study was to investigate the lipolytic activity of cold-adapted Antarctic marine bacteria and, furthermore, the combined effect of some environmental factors on this enzymatic process. Strains were assayed for lipolytic activity on a basal medium amended with seven individual fatty acid esters. A significant activity was observed for 148 isolates (95.5% of the total screened). The interactive effect of pH, temperature and NaCl concentration on the substrates was tested for six representative isolates, identified as Pseudoalteromonas, Psychrobacter and Vibrio. Differences between strains according to NaCl and pH tolerances were observed. Only one strain degraded the substrate more efficiently at 4 degrees C than at 15 degrees C. Our findings demonstrate that the lipolytic activity of Antarctic marine bacteria is rather variable, depending on culture conditions, and occurs in a wide range of salt concentration and pH. Isolation and characterization of bacteria that are able to efficiently remove lipids at low temperatures will provide insight into the possibility to use cold-adapted bacteria as a source of exploitable enzymes. Moreover, research on the interactive effects of salt concentration, pH and temperature will be useful to understand the true enzyme potentialities for industrial applications.

  2. [Characteristics of adhesion of epiphytic bacteria on leaves of the seagrass Zostera marina and on abiotic surfaces].

    Science.gov (United States)

    Kurilenko, V V; Ivanova, E P; Mikhaĭlov, V V

    2007-01-01

    A comparative study of the adhesion of epiphytic bacteria and marine free-living, saprophytic, and pathogenic bacteria on seagrass leaves and abiotic surfaces was performed to prove the occurrence of true epiphytes of Zostera marina and to elucidate the bacterium-plant symbiotrophic relationships. It was shown that in the course of adhesion to the seagrass leaves of two taxonomically different bacteria, Cytophaga sp. KMM 3552 and Pseudoalteromonas citrea KMM 461, isolated from the seagrass surface, the number of viable cells increased 3-7-fold after 60 h of incubation, reaching 1.0-2.0 x 10(5) cells/cm2; however, in the case of adhesion of these bacteria to abiotic surfaces, such as glass or metal, virtually no viable cells were observed after 60 h of incubation. Such selectivity of cell adhesion was not observed in the case of three other bacterial species studied, viz., Vibrio alginolyticus KMM 3551, Bacillus subtilis KMM 430, and Pseudomonas aeruginosa KMM 433. The amount of viable cells of V. alginolyticus KMM 3551 adsorbed on glass and metal surfaces increased twofold after 40 h of incubation. The cells of saprophytic B. subtilis KMM 430 and pathogenic P. aeruginosa KMM 433 adsorbed on three studied substrata remained viable for 36 h and died by the 60th hour of incubation.

  3. Potential of biogenic hydrogen production for hydrogen driven remediation strategies in marine environments.

    Science.gov (United States)

    Hosseinkhani, Baharak; Hennebel, Tom; Boon, Nico

    2014-09-25

    Fermentative production of bio-hydrogen (bio-H2) from organic residues has emerged as a promising alternative for providing the required electron source for hydrogen driven remediation strategies. Unlike the widely used production of H2 by bacteria in fresh water systems, few reports are available regarding the generation of biogenic H2 and optimisation processes in marine systems. The present research aims to optimise the capability of an indigenous marine bacterium for the production of bio-H2 in marine environments and subsequently develop this process for hydrogen driven remediation strategies. Fermentative conversion of organics in marine media to H2 using a marine isolate, Pseudoalteromonas sp. BH11, was determined. A Taguchi design of experimental methodology was employed to evaluate the optimal nutritional composition in batch tests to improve bio-H2 yields. Further optimisation experiments showed that alginate-immobilised bacterial cells were able to produce bio-H2 at the same rate as suspended cells over a period of several weeks. Finally, bio-H2 was used as electron donor to successfully dehalogenate trichloroethylene (TCE) using biogenic palladium nanoparticles as a catalyst. Fermentative production of bio-H2 can be a promising technique for concomitant generation of an electron source for hydrogen driven remediation strategies and treatment of organic residue in marine ecosystems. Copyright © 2014 Elsevier B.V. All rights reserved.

  4. Marine bacterial transparent exopolymer particles (TEP) and TEP precursors: Characterization and RO fouling potential

    KAUST Repository

    Li, Sheng

    2015-10-31

    This paper investigated the characteristics and membrane fouling potential of bacterial transparent exopolymer particles (TEP)/TEP precursors released from two marine bacteria, Pseudidiomarina homiensis (P. homiensis) and Pseudoalteromonas atlantica (P. atlantica), isolated from the Red Sea. Results showed that both bacteria grew at the similar rate, but the production of TEP/TEP precursors from P. atlantica was higher than that from P. homiensis. During the 168. h of incubation time, production rates of TEP/TEP precursors from P. atlantica and P. homiensis were 0.30 and 0.08 xanthan gum eq. mg/L-h, respectively. Isolated bacterial TEP precursors were mainly biopolymer, and P. atlantica produced a significantly higher concentration of biopolymer than that produced by P. homiensis. TEP/TEP precursors from both marine bacteria possessed protein-like material and were very similar in composition to previously reported foulants isolated from a fouled reverse osmosis (RO) membrane. Bacterial TEP/TEP precursors mostly consisted of aliphatic hydrocarbon from amino acids and amide group carbon of proteins (around 55%). Bacterial TEP precursors caused obvious fouling on RO membranes, which may create an ideal environment for bacteria attachment and promote to biofouling.

  5. Broad-Host-Range Expression Reveals Native and Host Regulatory Elements That Influence Heterologous Antibiotic Production in Gram-Negative Bacteria

    Directory of Open Access Journals (Sweden)

    Jia Jia Zhang

    2017-09-01

    Full Text Available Heterologous expression has become a powerful tool for studying microbial biosynthetic gene clusters (BGCs. Here, we extend the transformation-associated recombination cloning and heterologous expression platform for microbial BGCs to include Gram-negative proteobacterial expression hosts. Using a broad-host-range expression platform, we test the implicit assumption that biosynthetic pathways are more successfully expressed in more closely related heterologous hosts. Cloning and expression of the violacein BGC from Pseudoalteromonas luteoviolacea 2ta16 revealed robust production in two proteobacterial hosts, Pseudomonas putida KT2440 and Agrobacterium tumefaciens LBA4404, but very little production of the antibiotic in various laboratory strains of Escherichia coli, despite their closer phylogenetic relationship. We identified a nonclustered LuxR-type quorum-sensing receptor from P. luteoviolacea 2ta16, PviR, that increases pathway transcription and violacein production in E. coli by ∼60-fold independently of acyl-homoserine lactone autoinducers. Although E. coli harbors the most similar homolog of PviR identified from all of the hosts tested, overexpression of various E. coli transcription factors did not result in a statistically significant increase in violacein production, while overexpression of two A. tumefaciens PviR homologs significantly increased production. Thus, this work not only introduces a new genetic platform for the heterologous expression of microbial BGCs, it also challenges the assumption that host phylogeny is an accurate predictor of host compatibility.

  6. Biofilms and Marine Invertebrate Larvae: What Bacteria Produce That Larvae Use to Choose Settlement Sites

    Science.gov (United States)

    Hadfield, Michael G.

    2011-01-01

    Communities of microorganisms form thin coats across solid surfaces in the sea. Larvae of many marine invertebrates use biofilm components as cues to appropriate settlement sites. Research on the tube-dwelling polychaete worm Hydroides elegans, a globally common member of biofouling communities, is described to exemplify approaches to understanding biofilm bacteria as a source of settlement cues and larvae as bearers of receptors for bacterial cues. The association of species of the bacterial genus Pseudoalteromonas with larval settlement in many phyla is described, and the question of whether cues are soluble or surface-bound is reviewed, concluding that most evidence points to surface-bound cues. Seemingly contradictory data for stimulation of barnacle settlement are discussed; possibly both explanations are true. Paleontological evidence reveals a relationship between metazoans and biofilms very early in metazoan evolution, and thus the receptors for bacterial cues of invertebrate larvae are very old and possibly unique. Finally, despite more than 60 years of intense investigation, we still know very little about either the bacterial ligands that stimulate larval settlement or the cellular basis of their detection by larvae.

  7. Temporal and Spatial Differences in Microbial Composition during the Manufacture of a Continental-Type Cheese

    Science.gov (United States)

    O'Sullivan, Daniel J.; O'Sullivan, Orla; McSweeney, Paul L. H.; Sheehan, Jeremiah J.

    2015-01-01

    We sought to determine if the time, within a production day, that a cheese is manufactured has an influence on the microbial community present within that cheese. To facilitate this, 16S rRNA amplicon sequencing was used to elucidate the microbial community dynamics of brine-salted continental-type cheese in cheeses produced early and late in the production day. Differences in the microbial composition of the core and rind of the cheese were also investigated. Throughout ripening, it was apparent that cheeses produced late in the day had a more diverse microbial population than their early equivalents. Spatial variation between the cheese core and rind was also noted in that cheese rinds were initially found to have a more diverse microbial population but thereafter the opposite was the case. Interestingly, the genera Thermus, Pseudoalteromonas, and Bifidobacterium, not routinely associated with a continental-type cheese produced from pasteurized milk, were detected. The significance, if any, of the presence of these genera will require further attention. Ultimately, the use of high-throughput sequencing has facilitated a novel and detailed analysis of the temporal and spatial distribution of microbes in this complex cheese system and established that the period during a production cycle at which a cheese is manufactured can influence its microbial composition. PMID:25636841

  8. Characterization of the dominant bacterial communities during storage of Norway lobster and Norway lobster tails (Nephrops norvegicus) based on 16S rDNA analysis by PCR-DGGE.

    Science.gov (United States)

    Bekaert, Karen; Devriese, Lisa; Maes, Sara; Robbens, Johan

    2015-04-01

    The aim of this study was to investigate the microbial quality of whole Norway lobster (Nephrops norvegicus) and Norway lobster tails to optimize handling conditions. This was done by assessing the total viable count (TVC) and characterizing the dominant microbiota. The cultivable microorganisms were quantified via classical microbiological plating methods. To characterize as many bacterial species present as possible, we performed advanced molecular identification techniques (PCR-DGGE). The initial TVC of fresh Norway lobster meat was high (3.0 log cfu/g) as compared to fish. No significant difference between whole Norway lobster and Norway lobster tails could be found during the storage period. From day 6 of storage, a significant difference between Plate Count Agar (PCA) and Marine Agar (MA) was observed. The microbiota of Norway lobster was dominated by members of the Gram-negative genera such as Psychrobacter spp., Pseudoalteromonas spp., Pseudomonas spp., Luteimonas spp., and Aliivibrio spp. From these bacteria, mainly Psychrobacter spp. and Pseudomonas spp. remained present until the end of the storage period. These are known spoilage organisms in fishery products. Other known spoilage organisms of crustaceans such as Photobacterium spp. could not be identified. Copyright © 2014 Elsevier Ltd. All rights reserved.

  9. Characterization of culturable bacterial flora in yolk-sac larvae of Atlantic halibut (Hippoglossus hippoglossus L. with "gaping jaws" syndrome

    Directory of Open Access Journals (Sweden)

    Rocío Urtubia

    2014-03-01

    Full Text Available One of the main problems facing Atlantic halibut hatcheries is the high mortality in the early stages of larval development. Several factors could be involved, for example: water quality, diseases or abnormalities, such as deformities occurring in the yolk sac larvae prior to exogenous feeding. The aim of this study was to identify differences in bacterial flora associated with yolk sac larvae with oral deformity. We also aimed to establish whether there is any relationship between bacterial strains and the "gaping jaws" syndrome. During our study, 74 bacterial isolates were obtained using three different nutrient media: Marine Agar, R2A and TCBS. Some of these bacteria were characterized using Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP and 16S rRNA sequencing. The immune response in larvae exhibiting the "gaping jaws" condition was measured by real time PCR. Our results showed significant differences in bacterial flora between normal and gaping larvae. The gaping yolk sac larvae were predominantly colonized by members of the families Vibrionaceae and Flavobacteriaceae. Bacteria belonging to the Bacillus and Pseudoalteromonas genera were also present but less frequent. It was not possible to associate a type or group of bacteria directly related to "gaping". Strikingly, larvae with gaping jaws had an increase in the expression of two immune related genes, like hepcidin and chemokine (MIP-1B. These results indicate activation of the immune response in larvae with "gaping jaws" syndrome and this response could be related to bacteria isolated from gaping condition.

  10. Molecular Fingerprinting of Dairy Microbial Ecosystems by Use of Temporal Temperature and Denaturing Gradient Gel Electrophoresis

    Science.gov (United States)

    Ogier, J.-C.; Lafarge, V.; Girard, V.; Rault, A.; Maladen, V.; Gruss, A.; Leveau, J.-Y.; Delacroix-Buchet, A.

    2004-01-01

    Numerous microorganisms, including bacteria, yeasts, and molds, constitute the complex ecosystem present in milk and fermented dairy products. Our aim was to describe the bacterial ecosystem of various cheeses that differ by production technology and therefore by their bacterial content. For this purpose, we developed a rapid, semisystematic approach based on genetic profiling by temporal temperature gradient electrophoresis (TTGE) for bacteria with low-G+C-content genomes and denaturing gradient gel electrophoresis (DGGE) for those with medium- and high-G+C-content genomes. Bacteria in the unknown ecosystems were assigned an identity by comparison with a comprehensive bacterial reference database of ∼150 species that included useful dairy microorganisms (lactic acid bacteria), spoilage bacteria (e.g., Pseudomonas and Enterobacteriaceae), and pathogenic bacteria (e.g., Listeria monocytogenes and Staphylococcus aureus). Our analyses provide a high resolution of bacteria comprising the ecosystems of different commercial cheeses and identify species that could not be discerned by conventional methods; at least two species, belonging to the Halomonas and Pseudoalteromonas genera, are identified for the first time in a dairy ecosystem. Our analyses also reveal a surprising difference in ecosystems of the cheese surface versus those of the interior; the aerobic surface bacteria are generally G+C rich and represent diverse species, while the cheese interior comprises fewer species that are generally low in G+C content. TTGE and DGGE have proven here to be powerful methods to rapidly identify a broad range of bacterial species within dairy products. PMID:15345452

  11. Identification of bacterial strains isolated from the Mediterranean Sea exhibiting different abilities of biofilm formation.

    Science.gov (United States)

    Brian-Jaisson, Florence; Ortalo-Magné, Annick; Guentas-Dombrowsky, Linda; Armougom, Fabrice; Blache, Yves; Molmeret, Maëlle

    2014-07-01

    The Mediterranean Sea has rarely been investigated for the characterization of marine bacteria as compared to other marine environments such as the Atlantic or Pacific Ocean. Bacteria recovered from inert surfaces are poorly studied in these environments, when it has been shown that the community structure of attached bacteria can be dissimilar from that of planktonic bacteria present in the water column. The objectives of this study were to identify and characterize marine bacteria isolated from biofilms developed on inert surfaces immersed in the Mediterranean Sea and to evaluate their capacity to form a biofilm in vitro. Here, 13 marine bacterial strains have been isolated from different supports immersed in seawater in the Bay of Toulon (France). Phylogenetic analysis and different biological and physico-chemical properties have been investigated. Among the 13 strains recovered, 8 different genera and 12 different species were identified including 2 isolates of a novel bacterial species that we named Persicivirga mediterranea and whose genus had never been isolated from the Mediterranean Sea. Shewanella sp. and Pseudoalteromonas sp. were the most preponderant genera recovered in our conditions. The phenotypical characterization revealed that one isolate belonging to the Polaribacter genus differed from all the other ones by its hydrophobic properties and poor ability to form biofilms in vitro. Identifying and characterizing species isolated from seawater including from Mediterranean ecosystems could be helpful for example, to understand some aspects of bacterial biodiversity and to further study the mechanisms of biofilm (and biofouling) development in conditions approaching those of the marine environment.

  12. Petroleum-influenced beach sediments of the Campeche Bank, Mexico: diversity and bacterial community structure assessment.

    Science.gov (United States)

    Rosano-Hernández, María C; Ramírez-Saad, Hugo; Fernández-Linares, Luis

    2012-03-01

    The bacterial diversity and community structure were surveyed in intertidal petroleum-influenced sediments of ≈ 100 km of a beach, in the southern Gulf of Mexico. The beach was divided in twenty sampling sites according to high, moderate and low petroleum influence. Densities of cultured heterotrophic (HAB) and hydrocarbon degrading bacteria (HDB) were highly variable in sediments, with little morphological assortment in colonies. PCR-RISA banding patterns differentiated distinct communities along the beach, and the bacterial diversity changed inversely to the degree of petroleum hydrocarbon influence: the higher TPH concentration, the lower genotype diversity. Seven DNA sequences (Genbank EF191394 -EF191396 and EF191398 -EF191401) were affiliated to uncultured members of Gemmatimonas, Acidobacterium, Desulfobacteraceae, Rubrobacterales, Actinobacterium and the Fibrobacteres/Acidobacteria group; all the above taxa are known for having members with active roles in biogeochemical transformations. The remaining sequences (EF191388 - EF191393 and EF191397) affiliated to Pseudoalteromonas, and to oil-degrading genera such as Pseudomonas, Vibrio and Marinobacter, being the last one an obligate oil-degrading bacterium. An exchange of bacteria between the beach and the oil seep environment, and the potential cleaning-up role of bacteria at the southern Gulf of Mexico are discussed. Copyright © 2011 Elsevier Ltd. All rights reserved.

  13. Molecular Structure of Endotoxins from Gram-negative Marine Bacteria: An Update

    Directory of Open Access Journals (Sweden)

    Antonio Molinaro

    2007-09-01

    Full Text Available Marine bacteria are microrganisms that have adapted, through millions of years, to survival in environments often characterized by one or more extreme physical or chemical parameters, namely pressure, temperature and salinity. The main interest in the research on marine bacteria is due to their ability to produce several biologically active molecules, such as antibiotics, toxins and antitoxins, antitumor and antimicrobial agents. Nonetheless, lipopolysaccharides (LPSs, or their portions, from Gram-negative marine bacteria, have often shown low virulence, and represent potential candidates in the development of drugs to prevent septic shock. Besides, the molecular architecture of such molecules is related to the possibility of thriving in marine habitats, shielding the cell from the disrupting action of natural stress factors. Over the last few years, the depiction of a variety of structures of lipids A, core oligosaccharides and O-specific polysaccharides from LPSs of marine microrganisms has been given. In particular, here we will examine the most recently encountered structures for bacteria belonging to the genera Shewanella, Pseudoalteromonas and Alteromonas, of the γ-Proteobacteria phylum, and to the genera Flavobacterium, Cellulophaga, Arenibacter and Chryseobacterium, of the Cytophaga- Flavobacterium-Bacteroides phylum. Particular attention will be paid to the chemical features expressed by these structures (characteristic monosaccharides, non-glycidic appendages, phosphate groups, to the typifying traits of LPSs from marine bacteria and to the possible correlation existing between such features and the adaptation, over years, of bacteria to marine environments.

  14. Diversity of protease-producing marine bacteria from sub-antarctic environments.

    Science.gov (United States)

    Cristóbal, Héctor Antonio; López, Maria Alejandra; Kothe, Erika; Abate, Carlos Mauricio

    2011-12-01

    From seawater and the intestines of benthonic organisms collected from the Beagle Channel, Argentina, 230 marine bacteria were isolated. Cultivable bacteria were characterized and classified as psychrotolerant, whereas few isolates were psychrophiles. These isolates were capable of producing proteases at 4 and 15 °C under neutral (pH 7.0), alkaline (pH 10.0) and acidic (pH 4.5) conditions on different media, revealing 62, 33 and 22% producers at cold and 84, 47 and 33% producers at low temperatures, respectively. More protease-producing strains (67%) were detected when isolated from benthic invertebrates as compared to seawater (33%), with protease production under neutral conditions resulting in milk protein hydrolysis halos between 27 and 30 ± 2 mm in diameter. Using sterile 0.22 μm membrane filters, 29 isolates exhibiting extracellular protease activity were detected. These were grouped into six operational taxonomic units by restriction analysis and identified based on 16S rDNA as γ-proteobacteria of the genera Pseudoalteromonas, Pseudomonas, Shewanella, Alteromonas, Aeromonas, and Serratia. Plasmids were found to be harbored by eight strains, mainly within the isolates from benthonic organisms. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Phylogenentic and enzymatic characterization of psychrophilic and psychrotolerant marine bacteria belong to γ-Proteobacteria group isolated from the sub-Antarctic Beagle Channel, Argentina.

    Science.gov (United States)

    Cristóbal, Héctor A; Benito, Juliana; Lovrich, Gustavo A; Abate, Carlos M

    2015-05-01

    The phylogenetic and physiological characteristics of cultivable-dependent approaches were determined to establish the diversity of marine bacteria associated with the intestines of benthonic organisms and seawater samples from the Argentina's Beagle Channel. A total of 737 isolates were classified as psychrophlic and psychrotolerant culturable marine bacteria. These cold-adapted microorganisms are capable of producing cold-active glycosyl hydrolases, such as β-glucosidases, celulases, β-galactosidases, xylanases, chitinases, and proteases. These enzymes could have potential biotechnological applications for use in low-temperature manufacturing processes. According to polymerase chain reaction-restriction fragment length polymorphism analysis of part of genes encoding 16S ribosomal DNA (ARDRA) and DNA gyrase subunit B (gyrB-RFLP), 11 operational taxonomic units (OTU) were identified and clustered in known genera using InfoStat software. The 50 isolates selected were sequenced based on near full sequence analysis of 16S rDNA and gyrB sequences and identified by their nearest neighbors ranging between 96 and 99 % of identities. Phylogenetic analyses using both genes allowed relationships between members of the cultured marine bacteria belonging to the γ-Proteobacteria group (Aeromonas, Halteromonas, Pseudomonas, Pseudoalteromonas, Shewanella, Serratia, Colwellia, Glacielocola, and Psychrobacter) to be evaluated. Our research reveals a high diversity of hydrolytic bacteria, and their products actuality has an industrial use in several bioprocesses at low-temperature manufacturing.

  16. Bacterial diversity in the intestine of young farmed puffer fish Takifugu rubripes

    Science.gov (United States)

    Li, Yanyu; Zhang, Tao; Zhang, Congyao; Zhu, Ying; Ding, Jianfeng; Ma, Yuexin

    2015-07-01

    The aim of the study was to examine the bacterial community associated with the intestinal mucus of young farmed puffer fish Takifugu rubripes. Polymerase chain reaction and partial 16S rDNA sequencing was performed on DNA from bacteria cultivated on Zobell 2216E medium. All the isolates were classified into two phyla—Proteobacteria and Firmicutes. Proteobacteria were the dominant, culturable intestinal microbiota (68.3%). At the genus level, Vibrio, Enterobacter, Bacillus, Pseudomonas, Exiguobacterium, Staphylococcus, Acinetobacter, Pseudoalteromonas and Shewanella were isolated from the intestine, with representatives of the genera Vibrio, Enterobacter and Bacillus accounting for 70.7% of the total. This is the first report of Enterobacter, Bacillus, Exiguobacterium and Staphylococcus as part of the intestinal bacterial microflora in T. rubripes. The profile of the culturable bacterial community differed between samples collected from the same tank at 2-month intervals, as indicated by Bray-Curtis and Sorensen indices, and the impact on the intestinal physiology and health of puffer fish requires further investigation.

  17. Stable Associations Masked by Temporal Variability in the Marine Copepod Microbiome.

    Directory of Open Access Journals (Sweden)

    Pia H Moisander

    Full Text Available Copepod-bacteria interactions include permanent and transient epi- and endobiotic associations that may play roles in copepod health, transfer of elements in the food web, and biogeochemical cycling. Microbiomes of three temperate copepod species (Acartia longiremis, Centropages hamatus, and Calanus finmarchicus from the Gulf of Maine were investigated during the early summer season using high throughput amplicon sequencing. The most prominent stable component of the microbiome included several taxa within Gammaproteobacteria, with Pseudoalteromonas spp. especially abundant across copepod species. These Gammaproteobacteria appear to be promoted by the copepod association, likely benefitting from nutrient enriched microenvironments on copepods, and forming a more important part of the copepod-associated community than Vibrio spp. during the cold-water season in this temperate system. Taxon-specific associations included an elevated relative abundance of Piscirickettsiaceae and Colwelliaceae on Calanus, and Marinomonas sp. in Centropages. The communities in full and voided gut copepods had distinct characteristics, thus the presence of a food-associated microbiome was evident, including higher abundance of Rhodobacteraceae and chloroplast sequences in the transient communities. The observed variability was partially explained by collection date that may be linked to factors such as variable time since molting, gender differences, and changes in food availability and type over the study period. While some taxon-specific and stable associations were identified, temporal changes in environmental conditions, including food type, appear to be key in controlling the composition of bacterial communities associated with copepods in this temperate coastal system during the early summer.

  18. Effect of interspecific competition on trait variation in Phaeobacter inhibens biofilms.

    Science.gov (United States)

    Lutz, Carla; Thomas, Torsten; Steinberg, Peter; Kjelleberg, Staffan; Egan, Suhelen

    2016-05-01

    Interspecific competition between bacteria shapes community dynamics, causing evolutionary changes that affect life history traits. Here, we studied the role of interspecific competition on the generation of trait diversity using a two-species model system of marine, surface-associated bacteria. Bacterial biofilms of Phaeobacter inhibens were established alone or in competition with Pseudoalteromonas tunicata and phenotypic traits of dispersal cells were assessed during biofilm development. P. inhibens dispersal isolates from competition biofilms displayed less phenotypic variation, were superior competitors, were less susceptible to predation, and reached higher planktonic biomass than isolates from noncompetition biofilms. Moreover, the maintenance of competitive ability exhibited by individual dispersal isolates from competition biofilms did not result in an obvious reduction (measured as a negative trait correlation) in other traits, but was rather positively correlated with planktonic growth. However, where negative correlations between traits were found, they were exhibited by individuals derived from noncompetitive biofilms, whose populations also had a higher degree of trait variation than those from biofilms experiencing competition. Our observations indicate that interspecific competition during biofilm formation is important for maintaining both competitive ability and affects variation in ecologically relevant traits. Given that most bacteria in biofilms exist in diverse, multispecies communities, an understanding of how bacteria respond to biotic factors such as interspecific competition is critical for understanding the dynamics of bacterial populations in both ecological and evolutionary time. © 2016 Society for Applied Microbiology and John Wiley & Sons Ltd.

  19. Functional adaptations of the bacterial chaperone trigger factor to extreme environmental temperatures.

    Science.gov (United States)

    Godin-Roulling, Amandine; Schmidpeter, Philipp A M; Schmid, Franz X; Feller, Georges

    2015-07-01

    Trigger factor (TF) is the first molecular chaperone interacting cotranslationally with virtually all nascent polypeptides synthesized by the ribosome in bacteria. Thermal adaptation of chaperone function was investigated in TFs from the Antarctic psychrophile Pseudoalteromonas haloplanktis, the mesophile Escherichia coli and the hyperthermophile Thermotoga maritima. This series covers nearly all temperatures encountered by bacteria. Although structurally homologous, these TFs display strikingly distinct properties that are related to the bacterial environmental temperature. The hyperthermophilic TF strongly binds model proteins during their folding and protects them from heat-induced misfolding and aggregation. It decreases the folding rate and counteracts the fast folding rate imposed by high temperature. It also functions as a carrier of partially folded proteins for delivery to downstream chaperones ensuring final maturation. By contrast, the psychrophilic TF displays weak chaperone activities, showing that these functions are less important in cold conditions because protein folding, misfolding and aggregation are slowed down at low temperature. It efficiently catalyses prolyl isomerization at low temperature as a result of its increased cellular concentration rather than from an improved activity. Some chaperone properties of the mesophilic TF possibly reflect its function as a cold shock protein in E. coli. © 2014 Society for Applied Microbiology and John Wiley & Sons Ltd.

  20. New Ulvan-Degrading Polysaccharide Lyase Family: Structure and Catalytic Mechanism Suggests Convergent Evolution of Active Site Architecture.

    Science.gov (United States)

    Ulaganathan, ThirumalaiSelvi; Boniecki, Michal T; Foran, Elizabeth; Buravenkov, Vitaliy; Mizrachi, Naama; Banin, Ehud; Helbert, William; Cygler, Miroslaw

    2017-05-19

    Ulvan is a complex sulfated polysaccharide biosynthesized by green seaweed and contains predominantly rhamnose, xylose, and uronic acid sugars. Ulvan-degrading enzymes have only recently been identified and added to the CAZy ( www.cazy.org ) database as family PL24, but neither their structure nor catalytic mechanism(s) are yet known. Several homologous, new ulvan lyases, have been discovered in Pseudoalteromonas sp. strain PLSV, Alteromonas LOR, and Nonlabens ulvanivorans, defining a new family PL25, with the lyase encoded by the gene PLSV_3936 being one of them. This enzyme cleaves the glycosidic bond between 3-sulfated rhamnose (R3S) and glucuronic acid (GlcA) or iduronic acid (IdoA) via a β-elimination mechanism. We report the crystal structure of PLSV_3936 and its complex with a tetrasaccharide substrate. PLSV_3936 folds into a seven-bladed β-propeller, with each blade consisting of four antiparallel β-strands. Sequence conservation analysis identified a highly conserved region lining at one end of a deep crevice on the protein surface. The putative active site was identified by mutagenesis and activity measurements. Crystal structure of the enzyme with a bound tetrasaccharide substrate confirmed the identity of base and acid residues and allowed determination of the catalytic mechanism and also the identification of residues neutralizing the uronic acid carboxylic group. The PLSV_3936 structure provides an example of a convergent evolution among polysaccharide lyases toward a common active site architecture embedded in distinct folds.

  1. Lipopolysaccharides from Commensal and Opportunistic Bacteria: Characterization and Response of the Immune System of the Host Sponge Suberites domuncula

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    Johan Gardères

    2015-08-01

    Full Text Available Marine sponges harbor a rich bacterioflora with which they maintain close relationships. However, the way these animals make the distinction between bacteria which are consumed to meet their metabolic needs and opportunistic and commensal bacteria which are hosted is not elucidated. Among the elements participating in this discrimination, bacterial cell wall components such as lipopolysaccharides (LPS could play a role. In the present study, we investigated the LPS chemical structure of two bacteria associated with the sponge Suberites domuncula: a commensal Endozoicomonas sp. and an opportunistic Pseudoalteromonas sp. Electrophoretic patterns indicated different LPS structures for these bacteria. The immunomodulatory lipid A was isolated after mild acetic acid hydrolysis. The electrospray ionization ion-trap mass spectra revealed monophosphorylated molecules corresponding to tetra- and pentaacylated structures with common structural features between the two strains. Despite peculiar structural characteristics, none of these two LPS influenced the expression of the macrophage-expressed gene S. domuncula unlike the Escherichia coli ones. Further research will have to include a larger number of genes to understand how this animal can distinguish between LPS with resembling structures and discriminate between bacteria associated with it.

  2. Nigribactin, a Novel Siderophore from Vibrio nigripulchritudo, Modulates Staphylococcus aureus Virulence Gene Expression

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    Lone Gram

    2012-11-01

    Full Text Available Staphylococcus aureus is a serious human pathogen that employs a number of virulence factors as part of its pathogenesis. The purpose of the present study was to explore marine bacteria as a source of compounds that modulate virulence gene expression in S. aureus. During the global marine Galathea 3 expedition, a strain collection was established comprising bacteria that express antimicrobial activity against Vibrio anguillarum and/or Staphylococcus aureus. Within this collection we searched colony material, culture supernatants, and cell extracts for virulence modulating activity showing that 68 out of 83 marine bacteria (affiliated with the Vibrionaceae and Pseudoalteromonas sp. influenced expression of S. aureus hla encoding α-hemolysin toxin and/or spa encoding Protein A. The isolate that upon initial screening showed the highest degree of interference (crude ethyl acetate extract was a Vibrio nigripulchritudo. Extraction, purification and structural elucidation revealed a novel siderophore, designated nigribactin, which induces spa transcription. The effect of nigribactin on spa expression is likely to be independent from its siderophore activity, as another potent siderophore, enterobactin, failed to influence S. aureus virulence gene expression. This study shows that marine microorganisms produce compounds with potential use in therapeutic strategies targeting virulence rather than viability of human pathogens.

  3. Evaluation of the Activity of the Sponge Metabolites Avarol and Avarone and their Synthetic Derivatives Against Fouling Micro- and Macroorganisms

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    Vassilios Roussis

    2007-05-01

    Full Text Available The sesquiterpene hydroquinone avarol (1 was isolated from the marine sponge Dysidea avara, whereas the corresponding quinone, avarone (2, was obtained by oxidation of avarol, and the significantly more lipophilic compounds [3’-(p-chloro-phenylavarone (3, 3’,4’-ethylenedithioavarone (4, 4’-isopropylthioavarone (5, 4’-tert-butylthioavarone (6, 4’-propylthioavarone (7, 4’-octylthioavarone (8] were obtained by nucleophilic addition of thiols or p-chloroaniline to avarone. All these compounds were tested, at concentrations ranging from 0.5 to 50 μg/mL, for their effect on the settlement of the cyprid stage of Balanus amphitrite, for toxicity to both nauplii and cyprids and for their growth inhibitory activity on marine bacteria (Cobetia marina, Marinobacterium stanieri, Vibrio fischeri and Pseudoalteromonas haloplanktis and marine fungi (Halosphaeriopsis mediosetigera, Asteromyces cruciatus, Lulworthia uniseptata and Monodictys pelagica.

  4. Genomic Analysis of a Marine Bacterium: Bioinformatics for Comparison, Evaluation, and Interpretation of DNA Sequences

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    Bhagwan N. Rekadwad

    2016-01-01

    Full Text Available A total of five highly related strains of an unidentified marine bacterium were analyzed through their short genome sequences (AM260709–AM260713. Genome-to-Genome Distance (GGDC showed high similarity to Pseudoalteromonas haloplanktis (X67024. The generated unique Quick Response (QR codes indicated no identity to other microbial species or gene sequences. Chaos Game Representation (CGR showed the number of bases concentrated in the area. Guanine residues were highest in number followed by cytosine. Frequency of Chaos Game Representation (FCGR indicated that CC and GG blocks have higher frequency in the sequence from the evaluated marine bacterium strains. Maximum GC content for the marine bacterium strains ranged 53-54%. The use of QR codes, CGR, FCGR, and GC dataset helped in identifying and interpreting short genome sequences from specific isolates. A phylogenetic tree was constructed with the bootstrap test (1000 replicates using MEGA6 software. Principal Component Analysis (PCA was carried out using EMBL-EBI MUSCLE program. Thus, generated genomic data are of great assistance for hierarchical classification in Bacterial Systematics which combined with phenotypic features represents a basic procedure for a polyphasic approach on unambiguous bacterial isolate taxonomic classification.

  5. Distribution in Different Organisms of Amino Acid Oxidases with FAD or a Quinone As Cofactor and Their Role as Antimicrobial Proteins in Marine Bacteria

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    Jonatan C. Campillo-Brocal

    2015-12-01

    Full Text Available Amino acid oxidases (AAOs catalyze the oxidative deamination of amino acids releasing ammonium and hydrogen peroxide. Several kinds of these enzymes have been reported. Depending on the amino acid isomer used as a substrate, it is possible to differentiate between l-amino acid oxidases and d-amino acid oxidases. Both use FAD as cofactor and oxidize the amino acid in the alpha position releasing the corresponding keto acid. Recently, a novel class of AAOs has been described that does not contain FAD as cofactor, but a quinone generated by post-translational modification of residues in the same protein. These proteins are named as LodA-like proteins, after the first member of this group described, LodA, a lysine epsilon oxidase synthesized by the marine bacterium Marinomonas mediterranea. In this review, a phylogenetic analysis of all the enzymes described with AAO activity has been performed. It is shown that it is possible to recognize different groups of these enzymes and those containing the quinone cofactor are clearly differentiated. In marine bacteria, particularly in the genus Pseudoalteromonas, most of the proteins described as antimicrobial because of their capacity to generate hydrogen peroxide belong to the group of LodA-like proteins.

  6. Purification and characterization of cold-adapted beta-agarase from an Antarctic psychrophilic strain

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    Jiang Li

    2015-09-01

    Full Text Available An extracellular β-agarase was purified from Pseudoalteromonas sp. NJ21, a Psychrophilic agar-degrading bacterium isolated from Antarctic Prydz Bay sediments. The purified agarase (Aga21 revealed a single band on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, with an apparent molecular weight of 80 kDa. The optimum pH and temperature of the agarase were 8.0 and 30 °C, respectively. However, it maintained as much as 85% of the maximum activities at 10 °C. Significant activation of the agarase was observed in the presence of Mg2+, Mn2+, K+; Ca2+, Na+, Ba2+, Zn2+, Cu2+, Co2+, Fe2+, Sr2+ and EDTA inhibited the enzyme activity. The enzymatic hydrolyzed product of agar was characterized as neoagarobiose. Furthermore, this work is the first evidence of cold-adapted agarase in Antarctic psychrophilic bacteria and these results indicate the potential for the Antarctic agarase as a catalyst in medicine, food and cosmetic industries.

  7. Evaluation of the spoilage potential of bacteria isolated from spoiled cooked whole tropical shrimp (Penaeus vannamei) stored under modified atmosphere packaging.

    Science.gov (United States)

    Macé, Sabrina; Cardinal, Mireille; Jaffrès, Emmanuel; Cornet, Josiane; Lalanne, Valérie; Chevalier, Frédérique; Sérot, Thierry; Pilet, Marie-France; Dousset, Xavier; Joffraud, Jean-Jacques

    2014-06-01

    The spoilage potential of isolates belonging to five bacterial groups/species (Shewanella baltica, Carnobacterium maltaromaticum, Aeromonas salmonicida, Vibrio sp., "other Gamma-Proteobacteria" [containing one strain of Pseudoalteromonas sp. and one strain of Psychrobacter sp.]) isolated from spoiled cooked and whole tropical shrimp stored under modified atmosphere packaging (MAP) was evaluated by inoculation into ionized cooked and peeled tropical shrimp followed by storage for 32 days at 8 °C. Microbial growth and sensory changes were monitored during the storage period. The major spoilage bacterial isolate groups were C. maltaromaticum and S. baltica. In order to characterize their spoilage potential further and to study the effect of their interactions, each of these two specific spoilage organisms (SSO) and one mixed-culture, C. maltaromaticum/S. baltica, were tested using a combination of complementary methods: molecular (PCR-TTGE), sensory, chemical, and conventional microbiological analyses. It was concluded that, in the mixed-culture-inoculated samples, both species groups imposed their spoilage characteristics. Copyright © 2013 Elsevier Ltd. All rights reserved.

  8. Isolation, Characterisation and Antagonistic Activity of Bacteria Symbionts Hardcoral Pavona sp. Isolated from Panjang Island, Jepara Against Infectious Multi-drug Resistant (MDR) Bacteria

    Science.gov (United States)

    Ayuningrum, D.; Kristiana, R.; Asagabaldan, M. A.; Sabdono, A.; Radjasa, O. K.; Nuryadi, H.; Trianto, A.

    2017-02-01

    Pavona sp. is highly spread over Indonesian waters including Panjang Island. Several studies showed that bacteria symbionts hardcoral were the big source of antibiotic product, but there was limited research of the bacteria symbionts with hardcoral Pavona sp. In this research bacteria symbionts from hardcoral Pavona sp. had been collected from Panjang Island, Jepara. Marine bacteria symbionts were isolated by serial dillution method, while antibacterial activity was performed by using overlay and agar block method. The total of 2 from 5 isolates were active to MDR bacteria such as Enterobacter aerogenes and Acinetobacter baumanii, the code were PHC 44/04 and PHC 44/05. Then both of them were identified by morphological and molecular DNA characterization using 16 S rRNA gene sequence. The result of 16 S rRNA identification shows PHC 44/04 has 99% similarities with Virgibacillus salarius strain sa-Vb 1, while PHC 44/05 shows 99% similarities with Pseudoalteromonas flavipulchra strain NCIMB 2033.

  9. American lobsters (Homarus americanus not surviving during air transport: evaluation of microbial spoilage

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    Erica Tirloni

    2016-05-01

    Full Text Available Eighteen American lobsters (Homarus americanus, dead during air transport, were analysed in order to evaluate the microbial population of meat, gills and gut: no specific studies have ever been conducted so far on the microbiological quality of American lobsters’ meats in terms of spoilage microbiota. The meat samples showed very limited total viable counts, in almost all the cases below the level of 6 Log CFU/g, while higher loads were found, as expected, in gut and gills, the most probable source of contamination. These data could justify the possibility to commercialise these notsurviving subjects, without quality concerns for the consumers. Most of the isolates resulted to be clustered with type strains of Pseudoalteromonas spp. (43.1% and Photobacterium spp. (24.1%, and in particular to species related to the natural marine environment. The distribution of the genera showed a marked inhomogeneity among the samples. The majority of the isolates identified resulted to possess proteolytic (69.3% and lipolytic ability (75.5%, suggesting their potential spoilage ability. The maintanance of good hygienical practices, especially during the production of ready-to-eat lobsters-based products, and a proper storage could limit the possible replication of these microorganisms.

  10. Role of shellfish hatchery as a reservoir of antimicrobial resistant bacteria.

    Science.gov (United States)

    Miranda, Claudio D; Rojas, Rodrigo; Garrido, Marcela; Geisse, Julieta; González, Gerardo

    2013-09-15

    The main aim of this study was to determine the occurrence of resistant bacteria in florfenicol-treated and untreated scallop larval cultures from a commercial hatchery and to characterize some selected florfenicol-resistant strains. Larval cultures from untreated and treated rearing tanks exhibited percentages of copiotrophic bacteria resistant to florfenicol ranging from 0.03% to 10.67% and 0.49-18.34%, respectively, whereas florfenicol resistance among oligotrophic bacteria varied from 1.44% to 35.50% and 3.62-95.71%, from untreated and treated larvae, respectively. Florfenicol resistant microbiota from reared scallop larvae mainly belonged to the Pseudomonas and Pseudoalteromonas genus and were mainly resistant to florfenicol, chloramphenicol, streptomycin and co-trimoxazole. This is the first study reporting antimicrobial resistant bacteria associated to a shellfish hatchery and the results suggest that a continuous surveillance of antimicrobial resistance even in absence of antibacterial therapy is urgently required to evaluate potential undesirable consequences on the surrounding environments. Copyright © 2013 Elsevier Ltd. All rights reserved.

  11. Characterization of culturable bacteria isolated from the cold-water coral Lophelia pertusa

    Science.gov (United States)

    Galkiewicz, Julia P.; Pratte, Zoe A.; Gray, Michael A.; Kellogg, Christina A.

    2011-01-01

    Microorganisms associated with corals are hypothesized to contribute to the function of the host animal by cycling nutrients, breaking down carbon sources, fixing nitrogen, and producing antibiotics. This is the first study to culture and characterize bacteria from Lophelia pertusa, a cold-water coral found in the deep sea, in an effort to understand the roles that the microorganisms play in the coral microbial community. Two sites in the northern Gulf of Mexico were sampled over 2 years. Bacteria were cultured from coral tissue, skeleton, and mucus, identified by 16S rRNA genes, and subjected to biochemical testing. Most isolates were members of the Gammaproteobacteria, although there was one isolate each from the Betaproteobacteria and Actinobacteria. Phylogenetic results showed that both sampling sites shared closely related isolates (e.g. Pseudoalteromonas spp.), indicating possible temporally and geographically stable bacterial-coral associations. The Kirby-Bauer antibiotic susceptibility test was used to separate bacteria to the strain level, with the results showing that isolates that were phylogenetically tightly grouped had varying responses to antibiotics. These results support the conclusion that phylogenetic placement cannot predict strain-level differences and further highlight the need for culture-based experiments to supplement culture-independent studies.

  12. Bacterial communities associated with lesions of two forms of shell disease in the American lobster (Homarus americanus, Milne Edwards) from Atlantic Canada.

    Science.gov (United States)

    Quinn, Robert A; Cawthorn, Richard J; Summerfield, Rachael L; Smolowitz, Roxanna; Chistoserdov, Andrei Y

    2013-06-01

    Shell disease is a major threat to the American lobster (Homarus americanus, Milne Edwards) fishery. Here we describe the composition of microbial communities associated with lesions of 2 forms of shell disease in Atlantic Canada, (i) a trauma shell disease (TSD) characterized by massive lesions and (ii) an enzootic shell disease (EnSD) characterized by irregularly shaped lesions with a distinct orange to yellow color. The microbiology of the lesions was described by polymerase chain reaction and denaturing gradient gel electrophoresis of 16S rDNA amplified from scrapings of the shell lesions and was compared with communities of unaffected carapaces and previously described forms of shell diseases. Both TSD and EnSD lesions were dominated by members of Alphaproteobacteria, Gammaproteobacteria, and Flavobacteria, all commonly detected in other forms of shell disease; however, unique members of Epsilonproteobacteria were also present. Two Vibrio spp. and 2 Pseudoalteromonas spp. were dominant in lesions of TSD and a Tenacibaculum sp. and Tenacibaculum ovolyticum were dominant in lesions of EnSD. The TSD and EnSD in this study contained similar taxa as other shell disease forms; however, their microbiology is mostly different and neither resembles that of epizootic shell disease.

  13. MS/MS networking guided analysis of molecule and gene cluster families

    Science.gov (United States)

    Nguyen, Don Duy; Wu, Cheng-Hsuan; Moree, Wilna J.; Lamsa, Anne; Medema, Marnix H.; Zhao, Xiling; Gavilan, Ronnie G.; Aparicio, Marystella; Atencio, Librada; Jackson, Chanaye; Ballesteros, Javier; Sanchez, Joel; Watrous, Jeramie D.; Phelan, Vanessa V.; van de Wiel, Corine; Kersten, Roland D.; Mehnaz, Samina; De Mot, René; Shank, Elizabeth A.; Charusanti, Pep; Nagarajan, Harish; Duggan, Brendan M.; Moore, Bradley S.; Bandeira, Nuno; Palsson, Bernhard Ø.; Pogliano, Kit; Gutiérrez, Marcelino; Dorrestein, Pieter C.

    2013-01-01

    The ability to correlate the production of specialized metabolites to the genetic capacity of the organism that produces such molecules has become an invaluable tool in aiding the discovery of biotechnologically applicable molecules. Here, we accomplish this task by matching molecular families with gene cluster families, making these correlations to 60 microbes at one time instead of connecting one molecule to one organism at a time, such as how it is traditionally done. We can correlate these families through the use of nanospray desorption electrospray ionization MS/MS, an ambient pressure MS technique, in conjunction with MS/MS networking and peptidogenomics. We matched the molecular families of peptide natural products produced by 42 bacilli and 18 pseudomonads through the generation of amino acid sequence tags from MS/MS data of specific clusters found in the MS/MS network. These sequence tags were then linked to biosynthetic gene clusters in publicly accessible genomes, providing us with the ability to link particular molecules with the genes that produced them. As an example of its use, this approach was applied to two unsequenced Pseudoalteromonas species, leading to the discovery of the gene cluster for a molecular family, the bromoalterochromides, in the previously sequenced strain P. piscicida JCM 20779T. The approach itself is not limited to 60 related strains, because spectral networking can be readily adopted to look at molecular family–gene cluster families of hundreds or more diverse organisms in one single MS/MS network. PMID:23798442

  14. Culturable heterotrophic bacteria from Potter Cove, Antarctica, and their hydrolytic enzymes production

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    Mauro Tropeano

    2012-12-01

    Full Text Available Affiliations of the dominant culturable bacteria isolated from Potter Cove, South Shetland Islands, Antarctica, were investigated together with their production of cold-active hydrolytic enzymes. A total of 189 aerobic heterotrophic bacterial isolates were obtained at 4°C and sorted into 63 phylotypes based on their amplified ribosomal DNA restriction analysis profiles. The sequencing of the 16S rRNA genes of representatives from each phylotype showed that the isolates belong to the phyla Proteobacteria (classes Alpha- and Gamma-proteobacteria, Bacteroidetes (class Flavobacteria, Actinobacteria (class Actinobacteria and Firmicutes (class Bacilli. The predominant culturable group in the site studied belongs to the class Gammaproteobacteria, with 65 isolates affiliated to the genus Pseudoalteromonas and 58 to Psychrobacter. Among the 189 isolates screened, producers of amylases (9.5%, pectinases (22.8%, cellulases (14.8%, CM-cellulases (25.4%, xylanases (20.1% and proteases (44.4% were detected. More than 25% of the isolates produced at least one extracellular enzyme, with some of them producing up to six of the tested extracellular enzymatic activities. These results suggest that a high culturable bacterial diversity is present in Potter Cove and that this place represents a promising source of biomolecules.

  15. Diversity of both the cultivable protease-producing bacteria and bacterial extracellular proteases in the coastal sediments of King George Island, Antarctica.

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    Ming-Yang Zhou

    Full Text Available Protease-producing bacteria play a vital role in degrading sedimentary organic nitrogen. However, the diversity of these bacteria and their extracellular proteases in most regions remain unknown. In this paper, the diversity of the cultivable protease-producing bacteria and of bacterial extracellular proteases in the sediments of Maxwell Bay, King George Island, Antarctica was investigated. The cultivable protease-producing bacteria reached 10(5 cells/g in all 8 sediment samples. The cultivated protease-producing bacteria were mainly affiliated with the phyla Actinobacteria, Firmicutes, Bacteroidetes, and Proteobacteria, and the predominant genera were Bacillus (22.9%, Flavobacterium (21.0% and Lacinutrix (16.2%. Among these strains, Pseudoalteromonas and Flavobacteria showed relatively high protease production. Inhibitor analysis showed that nearly all the extracellular proteases from the bacteria were serine proteases or metalloproteases. These results begin to address the diversity of protease-producing bacteria and bacterial extracellular proteases in the sediments of the Antarctic Sea.

  16. American Lobsters (Homarus Americanus) not Surviving During Air Transport: Evaluation of Microbial Spoilage.

    Science.gov (United States)

    Tirloni, Erica; Stella, Simone; Gennari, Mario; Colombo, Fabio; Bernardi, Cristian

    2016-04-19

    Eighteen American lobsters (Homarus americanus), dead during air transport, were analysed in order to evaluate the microbial population of meat, gills and gut: no specific studies have ever been conducted so far on the microbiological quality of American lobsters' meats in terms of spoilage microbiota. The meat samples showed very limited total viable counts, in almost all the cases below the level of 6 Log CFU/g, while higher loads were found, as expected, in gut and gills, the most probable source of contamination. These data could justify the possibility to commercialise these not-surviving subjects, without quality concerns for the consumers. Most of the isolates resulted to be clustered with type strains of Pseudoalteromonas spp. (43.1%) and Photobacterium spp. (24.1%), and in particular to species related to the natural marine environment. The distribution of the genera showed a marked inhomogeneity among the samples. The majority of the isolates identified resulted to possess proteolytic (69.3%) and lipolytic ability (75.5%), suggesting their potential spoilage ability. The maintanance of good hygienical practices, especially during the production of ready-to-eat lobsters-based products, and a proper storage could limit the possible replication of these microorganisms.

  17. Marine Anti-Fouling Behavior of Lubricant-Infused Nanowrinkled Polymeric Surfaces.

    Science.gov (United States)

    Ware, Cameron S; Smith-Palmer, Truis; Peppou-Chapman, Sam; Scarratt, Liam R; Humphries, Erin; Balzer, Daniel; Neto, Chiara

    2017-12-18

    A new family of polymeric, lubricant-infused, nanostructured wrinkled surfaces was designed that effectively retains inert non-toxic silicone oil, upon draining by spin-coating and vigorous shear for two weeks. The wrinkled surfaces were fabricated using three different polymers (Teflon AF, polystyrene, and poly(4-vinylpyridine)) and two shrinkable substrates (polyshrink and shrinkwrap), and Teflon on polyshrink was found to be the most effective system. The volume of trapped lubricant was quantified by adding Nile red to the silicone oil before infusion, then extracting the oil and Nile red from the surfaces in heptane and measuring by fluorimetry. Higher volumes of lubricant induced lower roll-off angles for water droplets, and in turn induced better antifouling performance. The infused surfaces displayed stability in seawater and inhibited growth of Pseudoalteromonas spp. bacteria up to 99%, with as little as 0.9 μL cm-2 of silicone oil infused. Field tests in the waters of Sydney Harbour over seven weeks showed that silicone oil infusion inhibited the attachment of algae, but as the silicone oil was slowly depleted over time algal attachment increased. The infused wrinkled surfaces have high transparency and are moldable, making them suited to protecting the windows of underwater sensors and cameras.

  18. Chitosan-zinc oxide nanocomposite coatings for the prevention of marine biofouling.

    Science.gov (United States)

    Al-Naamani, Laila; Dobretsov, Sergey; Dutta, Joydeep; Burgess, J Grant

    2017-02-01

    Marine biofouling is a worldwide problem affecting maritime industries. Global concerns about the high toxicity of antifouling paints have highlighted the need to develop less toxic antifouling coatings. Chitosan is a natural polymer with antimicrobial, antifungal and antialgal properties that is obtained from partial deacetylation of crustacean waste. In the present study, nanocomposite chitosan-zinc oxide (chitosan-ZnO) nanoparticle hybrid coatings were developed and their antifouling activity was tested. Chitosan-ZnO nanoparticle coatings showed anti-diatom activity against Navicula sp. and antibacterial activity against the marine bacterium Pseudoalteromonas nigrifaciens. Additional antifouling properties of the coatings were investigated in a mesocosm study using tanks containing natural sea water under controlled laboratory conditions. Each week for four weeks, biofilm was removed and analysed by flow cytometry to estimate total bacterial densities on the coated substrates. Chitosan-ZnO hybrid coatings led to better inhibition of bacterial growth in comparison to chitosan coatings alone, as determined by flow cytometry. This study demonstrates the antifouling potential of chitosan-ZnO nanocomposite hybrid coatings, which can be used for the prevention of biofouling. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Fermentation Technologies for the Optimization of Marine Microbial Exopolysaccharide Production

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    Ilaria Finore

    2014-05-01

    Full Text Available In the last decades, research has focused on the capabilities of microbes to secrete exopolysaccharides (EPS, because these polymers differ from the commercial ones derived essentially from plants or algae in their numerous valuable qualities. These biopolymers have emerged as new polymeric materials with novel and unique physical characteristics that have found extensive applications. In marine microorganisms the produced EPS provide an instrument to survive in adverse conditions: They are found to envelope the cells by allowing the entrapment of nutrients or the adhesion to solid substrates. Even if the processes of synthesis and release of exopolysaccharides request high-energy investments for the bacterium, these biopolymers permit resistance under extreme environmental conditions. Marine bacteria like Bacillus, Halomonas, Planococcus, Enterobacter, Alteromonas, Pseudoalteromonas, Vibrio, Rhodococcus, Zoogloea but also Archaea as Haloferax and Thermococcus are here described as EPS producers underlining biopolymer hyperproduction, related fermentation strategies including the effects of the chemical composition of the media, the physical parameters of the growth conditions and the genetic and predicted experimental design tools.

  20. A bacterial quorum-sensing precursor induces mortality in the marine coccolithophore, Emiliania huxleyi

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    Elizabeth L Harvey

    2016-02-01

    Full Text Available Interactions between phytoplankton and bacteria play a central role in mediating biogeochemical cycling and food web structure in the ocean. However, deciphering the chemical drivers of these interspecies interactions remains challenging. Here we report the isolation of 2-heptyl-4-quinolone (HHQ, released by Pseudoalteromonas piscicida, a marine gamma-proteobacteria previously reported to induce phytoplankton mortality through a hitherto unknown algicidal mechanism. HHQ functions as both an antibiotic and a bacterial signaling molecule in cell-cell communication in clinical infection models. Co-culture of the bloom-forming coccolithophore, Emiliania huxleyi with both live P. piscicida and cell-free filtrates caused a significant decrease in algal growth. Investigations of the P. piscicida exometabolome revealed HHQ, at nanomolar concentrations, induced mortality in three strains of E. huxleyi. Mortality of E. huxleyi in response to HHQ occurred slowly, implying static growth rather than a singular loss event (e.g. rapid cell lysis. In contrast, the marine chlorophyte, Dunaliella tertiolecta and diatom, Phaeodactylum tricornutum were unaffected by HHQ exposures. These results suggest that HHQ mediates the type of interkingdom interactions that cause shifts in phytoplankton population dynamics. These chemically mediated interactions, and other like it, ultimately influence large-scale oceanographic processes.

  1. Reconstructing Holocene seasonal hydrographic variability in the eastern North Atlantic using bivalve shells from St Kilda, Scotland

    Science.gov (United States)

    Alexandroff, Stella; Scourse, James; Butler, Paul; Schöne, Bernd; Reimer, Paula

    2017-04-01

    Bivalve shells like Arctica islandica and Glycymeris glycymeris can be used as highly resolved archives of past marine climate and long-term biomonitors. The annual growth patterns of the shell reflect the environment the animals live in and by cross-matching these growth patterns it is possible to construct multi-centennial, annually resolved chronologies that form a temporal template for isotope sampling. The aim of this study is to detect a signal of Atlantic hydrographic variability in Scottish Shelf Seas that is as far as possible uncontaminated by other influences. In May 2014, we collected dead valves and young live specimens of G. glycymeris from St Kilda, Outer Hebrides, Scotland, and in April 2016, live specimens of A. islandica were collected at the same location. This area is of particular interest as it is close to the Scottish shelf margin, has negligible freshwater input, and is thought to represent open-ocean North Atlantic signals well. We here present two floating chronologies, each spanning >180 years, built from dead-collected G. glycymeris shells from St Kilda. All the shells in these chronologies were assigned radiocarbon ages between 3700-3300 cal yr BP. By combining the radiocarbon dates and the chronological data derived from cross-matching annual bands in the shells, one of the floating chronologies could be further constrained to 3750-3500 cal yr BP (95% range). Sub-annual δ18O data from the floating chronologies and from the modern specimens show a strong seasonal signal and multi-year trends. We calibrate the δ18O results from the modern specimens with instrumental data, which enables us (subject to the assumption that there has been no change in δ18Owater) to compare mean and seasonal seawater temperatures between the present day and the fourth millennium BP.

  2. Biological and Climate Controls on North Atlantic Marine Carbon Dynamics Over the Last Millennium: Insights From an Absolutely Dated Shell-Based Record From the North Icelandic Shelf

    Science.gov (United States)

    Reynolds, D. J.; Hall, I. R.; Scourse, J. D.; Richardson, C. A.; Wanamaker, A. D.; Butler, P. G.

    2017-12-01

    Given the rapid increase in atmospheric carbon dioxide concentrations (pCO2) over the industrial era, there is a pressing need to construct long-term records of natural carbon cycling prior to this perturbation and to develop a more robust understanding of the role the oceans play in the sequestration of atmospheric carbon. Here we reconstruct the past biological and climate controls on the carbon isotopic (δ13Cshell) composition of the North Icelandic shelf waters over the last millennium, derived from the shells of the long-lived marine bivalve mollusk Arctica islandica. Variability in the annually resolved δ13Cshell record is dominated by multidecadal variability with a negative trend (-0.003 ± 0.002‰ yr-1) over the industrial era (1800-2000 Common Era). This trend is consistent with the marine Suess effect brought about by the sequestration of isotopically light carbon (δ13C of CO2) derived from the burning of fossil fuels. Comparison of the δ13Cshell record with Contemporaneous proxy archives, over the last millennium, and instrumental data over the twentieth century, highlights that both biological (primary production) and physical environmental factors, such as relative shifts in the proportion of Subpolar Mode Waters and Arctic Intermediate Waters entrained onto the North Icelandic shelf, atmospheric circulation patterns associated with the winter North Atlantic Oscillation, and sea surface temperature and salinity of the subpolar gyre, are the likely mechanisms that contribute to natural variations in seawater δ13C variability on the North Icelandic shelf. Contrasting δ13C fractionation processes associated with these biological and physical mechanisms likely cause the attenuated marine Suess effect signal at this locality.

  3. The death assemblage as a marker for habitat and an indicator of climate change: Georges Bank, surfclams and ocean quahogs

    Science.gov (United States)

    Powell, Eric N.; Kuykendall, Kelsey M.; Moreno, Paula

    2017-06-01

    A comprehensive dataset for the Georges Bank region is used to directly compare the distribution of the death assemblage and the living community at large spatial scales and to assess the application of the death assemblage in tracking changes in species' distributional pattern as a consequence of climate change. Focus is placed on the biomass-dominant clam species of the northwest Atlantic continental shelf: the surfclam Spisula solidissima and the ocean quahog Arctica islandica, for which extensive datasets exist on the distributions of the living population and the death assemblage. For both surfclams and ocean quahogs, the distribution of dead shells, in the main, tracked the distribution of live animals relatively closely. Thus, for both species, the presence of dead shells was a positive indicator of present, recent, or past occupation by live animals. Shell dispersion within habitat was greater for surfclams than for ocean quahogs either due to spatial time averaging, animals not living in all habitable areas all of the time, or parautochthonous redistribution of shell. The regional distribution of dead shell differed from the distribution of live animals, for both species, in a systematic way indicative of range shifts due to climate change. In each case the differential distribution was consistent with warming of the northwest Atlantic. Present-day overlap of live surfclams with live ocean quahogs was consistent with the expectation that the surfclam's range is shifting into deeper water in response to the recent warming trend. The presence of locations devoid of dead shells where live surfclams nevertheless were collected measures the recentness of this event. The presence of dead ocean quahog shells at shallower depths than live ocean quahogs offers good evidence that a range shift has occurred in the past, but prior to the initiation of routine surveys in 1980. Possibly, this range shift tracks initial colonization at the end of the Little Ice Age.

  4. Temporal variation in atmospheric ammonia concentrations above seabird colonies

    Science.gov (United States)

    Blackall, T. D.; Wilson, L. J.; Bull, J.; Theobald, M. R.; Bacon, P. J.; Hamer, K. C.; Wanless, S.; Sutton, M. A.

    Recent studies have shown that seabirds are an important source of ammonia (NH 3) emissions in remote coastal ecosystems. Nesting behaviour, which varies between seabird species, is likely to be a major factor in determining the proportion of excreted nitrogen (N) volatilised to the atmosphere as NH 3. A long-term NH 3 monitoring programme was implemented at a Scottish seabird colony with a range of species and associated nesting behaviours. The average monthly NH 3 concentration was measured at 12 locations over a 14-month period, to infer spatial (i.e. species-specific) and temporal (seasonal) changes in NH 3 emissions from different seabird species. An emissions model of seabird NH 3, based on species-specific bioenergetics and behaviour, was applied to produce spatial estimates for input to a dispersion model. Atmospheric NH 3 concentrations demonstrated spatial variability as a result of differing local populations of breeding seabirds, with the highest concentrations measured above cliff nesting species such as Common guillemot Uria aalge, Razorbill Alca torda and Black-legged kittiwake Rissa tridactyla. NH 3 concentrations above a colony of burrow nesting Atlantic puffin Fratercula arctica were low, considering the high number of birds. Emission of NH 3 from excreted N exhibits a time lag of approximately a month. It is likely that all excreted N is lost from the colony by volatilisation as NH 3 or surface run-off between breeding seasons. Modelled NH 3 emissions and concentrations correlated with measured concentrations, but were much higher, reflecting uncertainties in the local turbulent characteristics. The results allow multi-species seabird population data to be used for the calculation of regional and global NH 3 emission inventories, whilst improving understanding of N budgets of remote coastal ecosystems.

  5. Diel Variation of Biogenic Volatile Organic Compound Emissions--A field Study in the Sub, Low and High Arctic on the Effect of Temperature and Light.

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    Frida Lindwall

    Full Text Available Many hours of sunlight in the midnight sun period suggest that significant amounts of biogenic volatile organic compounds (BVOCs may be released from arctic ecosystems during night-time. However, the emissions from these ecosystems are rarely studied and limited to point measurements during daytime. We measured BVOC emissions during 24-hour periods in the field using a push-pull chamber technique and collection of volatiles in adsorbent cartridges followed by analysis with gas chromatography-mass spectrometry. Five different arctic vegetation communities were examined: high arctic heaths dominated by Salix arctica and Cassiope tetragona, low arctic heaths dominated by Salix glauca and Betula nana and a subarctic peatland dominated by the moss Warnstorfia exannulata and the sedge Eriophorum russeolum. We also addressed how climate warming affects the 24-hour emission and how the daytime emissions respond to sudden darkness. The emissions from the high arctic sites were lowest and had a strong diel variation with almost no emissions during night-time. The low arctic sites as well as the subarctic site had a more stable release of BVOCs during the 24-hour period with night-time emissions in the same range as those during the day. These results warn against overlooking the night period when considering arctic emissions. During the day, the quantity of BVOCs and the number of different compounds emitted was higher under ambient light than in darkness. The monoterpenes α-fenchene, α-phellandrene, 3-carene and α-terpinene as well as isoprene were absent in dark measurements during the day. Warming by open top chambers increased the emission rates both in the high and low arctic sites, forewarning higher emissions in a future warmer climate in the Arctic.

  6. Ocean-wide Drivers of Migration Strategies and Their Influence on Population Breeding Performance in a Declining Seabird.

    Science.gov (United States)

    Fayet, Annette L; Freeman, Robin; Anker-Nilssen, Tycho; Diamond, Antony; Erikstad, Kjell E; Fifield, Dave; Fitzsimmons, Michelle G; Hansen, Erpur S; Harris, Mike P; Jessopp, Mark; Kouwenberg, Amy-Lee; Kress, Steve; Mowat, Stephen; Perrins, Chris M; Petersen, Aevar; Petersen, Ib K; Reiertsen, Tone K; Robertson, Gregory J; Shannon, Paula; Sigurðsson, Ingvar A; Shoji, Akiko; Wanless, Sarah; Guilford, Tim

    2017-12-18

    Which factors shape animals' migration movements across large geographical scales, how different migratory strategies emerge between populations, and how these may affect population dynamics are central questions in the field of animal migration [1] that only large-scale studies of migration patterns across a species' range can answer [2]. To address these questions, we track the migration of 270 Atlantic puffins Fratercula arctica, a red-listed, declining seabird, across their entire breeding range. We investigate the role of demographic, geographical, and environmental variables in driving spatial and behavioral differences on an ocean-basin scale by measuring puffins' among-colony differences in migratory routes and day-to-day behavior (estimated with individual daily activity budgets and energy expenditure). We show that competition and local winter resource availability are important drivers of migratory movements, with birds from larger colonies or with poorer local winter conditions migrating further and visiting less-productive waters; this in turn led to differences in flight activity and energy expenditure. Other behavioral differences emerge with latitude, with foraging effort and energy expenditure increasing when birds winter further north in colder waters. Importantly, these ocean-wide migration patterns can ultimately be linked with breeding performance: colony productivity is negatively associated with wintering latitude, population size, and migration distance, which demonstrates the cost of competition and migration on future breeding and the link between non-breeding and breeding periods. Our results help us to understand the drivers of animal migration and have important implications for population dynamics and the conservation of migratory species. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Deep vertical propagation of mountain waves above Scandinavia

    Science.gov (United States)

    Dörnbrack, Andreas; Gisinger, Sonja; Rapp, Markus; Witschas, Benjamin; Ehard, Benedikt; Wagner, Johannes; Achtert, Peggy; Stober, Gunter; Kivi, Rigel; Gumbel, Jörg

    2015-04-01

    The project "Investigation of the life cycle of gravity waves (GW-LCYCLE) is part of the German research initiative ROMIC (Role of the Middle atmosphere In Climate) funded by the ministry of research. In close cooperation with Scandinavian partners as the Stockholm University and the Finnish Meteorological Institute a first field phase was conducted in November/December 2013. The field program combined ground-based observations of tropospheric and lower stratospheric flow and stratospheric and mesospheric temperature by lidars and radars at Alomar (N) and at Esrange (S) with airborne and balloonborne observations. Northern Scandinavia was chosen since the westerly flow across the mountains is often aligned with the polar night jet permitting gravity waves (GWs) to propagate into the middle atmosphere. From 2 until 14 December 2013, 24 hours of the DLR Falcon flown in four intensive observing periods (IOPs) provided in-situ and remote-sensing observations of atmospheric wind, temperature, water vapour and other trace gases (e.g. CO, N2O, O3) in the vicinity of the tropopause. During three IOPs, the airborne observations were supported by 3 hourly simultaneous radiosonde launches from Andøya (N), Esrange(S) and Sodankylä (FIN). Additionally, 1.5 hourly high-frequency radiosonde launches were conducted from the Arena Arctica at Kiruna airport with two systems (Väisälä and GRAW)and different balloon fillings to obtain different ascent rates. During GW-LCYCLE, the atmospheric flow above the Scandinavian mountains was observed under distinct meteorological conditions enabling or attenuating the deep vertical propagation of mountain-induced gravity waves. The presentation juxtaposes two different cases and analyses the associated meteorological conditions. The unique combination of airborne tropospheric wind lidar measurements, flight level data, high-frequency radiosonde profiles and the ground-based lidar observations allow a comprehensive study of deeply

  8. Natural variability of parasite communities of Macrouridae of the middle and lower slope of the Mediterranean Sea and their relation with fish diet and health indicators

    Science.gov (United States)

    Pérez-i-García, D.; Constenla, M.; Soler-Membrives, A.; Cartes, J. E.; Solé, M.; Carrassón, M.

    2017-06-01

    This study examines the parasite communities of Coelorinchus caelorhincus, Coelorinchus mediterraneus, Coryphaenoides guentheri and Coryphaenoides mediterraneus of the middle and lower slopes of the Mediterranean Sea. Histopathological, enzymatic activity (acetylcholinesterase and lactate dehydrogenase), dietary and environmental (oxygen, salinity, temperature and turbidity) information were also obtained. A total of 11 parasite taxa were found in the four fish species, the copepod Hamaticolax resupinus being the only parasite shared by all of them. Coelorinchus mediterraneus, Coryphaenoides guentheri and Cor. mediterraneus exhibited rather homogeneous parasite communities, especially in the case of the latter two. Coelorinchus mediterraneus showed the highest richness of parasite taxa (eight species), whereas C. guentheri and Cor. mediterraneus harboured up to five and six, respectively, and C. caelorhincus up to three. Several of the parasites encountered occurred at very low prevalences (diet was generally homogeneous between the studied species, C. guentheri being more specialized on suprabenthic/benthic prey. The parasites H. aduncum and Tetraphylidea, and to lesser extent Raphidascaris sp., were associated with the most mobile (swimming) prey consumed by macrourids (Chaetognaths, decapod larvae, and Boreomysis arctica). The parasites L. desclersae, Capillostrongyloides morae and Otodistomum sp. were associated in Coe. mediterraneus with epibenthic prey (ophiuroids, isopods and tanaids). Coryphaenoides guentheri was the smallest macrourid analysed, with the poorest parasite fauna with higher proportion of larval stages. Few histopathological alterations were found, epitheliocystis being the most wide-spread and prevalent. Few parasite effects on fish health were reflected at enzymatic and histological level, probably due to the low parasite burden in their hosts. It is possible that the major role of small macrourids, especially C. guentheri, is to act as an

  9. Earlier Latin Grammars as (Indirect Sources for the First Slovene Grammar Written by Adam Bohorič

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    Kozma Ahačič

    2006-07-01

    Full Text Available The paper describes some possible sources, direct and indirect, for the grammar authored by the Slovene Protestant writer Adam Bohorič. Entitled Arcticae horulae succisivae de Latinocarniolana literatura(Winter Hours of Leisure on Latin-Carniolian Grammar, it was published in 1584 as the first grammar of Slovene. Since its language is Latin, the present discussion is limited to Latin grammar works. The two direct sources of Bohorič's chapter on etymology are identified as the second or third set of editions of Melanchthon's grammar (i.e., the text as edited in 1540 by Iacobus Micyllus and slightly revised in 1550 by Joachim Camerarius and as one of the (probably bilingual editions of Donatus published before 1540 (perhaps the so-called "Torgauer Donat", of which we had access to the edition Aelii Donati Methodus ?eu Declinandi coniungandique prima elementa, pro pueris Alphabetarijs, rerum grammaticarum pror?us ignaris, diligentiori cura nunc primum concinata. Cum Epistola Phil. Mel., Vitebergae, 1542. The direct source of Bohorič's chapter on syntax is identified as the second set of editions of Melanchthon's syntax, edited in 1538 by Vitus Oertelius Winshemius. The editions of Melanchthon's Latin grammar and syntax not used by Bohorič are likewise treated in detail. Among the indirect sources, there is a brief reference to Priscian's oeuvre, with detailed descriptions reserved for the major Latin humanist grammars published before Bohorič's work: Valla, Perotti, Perger, Sulpicius, Nebrija, Manutius, Despauterius, Linacre, Alvarus, Scaliger, and Ramus.

  10. Numerical simulation of extreme snowmelt observed at the SIGMA-A site, northwest Greenland, during summer 2012

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    M. Niwano

    2015-05-01

    Full Text Available The surface energy balance (SEB from 30 June to 14 July 2012 at site SIGMA (Snow Impurity and Glacial Microbe effects on abrupt warming in the Arctic-A, (78°03' N, 67°38' W; 1490 m a.s.l. on the northwest Greenland Ice Sheet (GrIS was investigated by using in situ atmospheric and snow measurements as well as numerical modeling with a one-dimensional multi-layered physical snowpack model called SMAP (Snow Metamorphism and Albedo Process. At SIGMA-A, remarkable near-surface snowmelt and continuous heavy rainfall (accumulated precipitation between 10 and 14 July was estimated to be 100 mm were observed after 10 July 2012. Application of the SMAP model to the GrIS snowpack was evaluated based on the snow temperature profile, snow surface temperature, surface snow grain size, and shortwave albedo, all of which the model simulated reasonably well. Above all, the fact that the SMAP model successfully reproduced frequently observed rapid increases in snow albedo under cloudy conditions highlights the advantage of the physically based snow albedo model (PBSAM incorporated in the SMAP model. Using such data and model, we estimated the SEB at SIGMA-A from 30 June to 14 July 2012. Radiation-related fluxes were obtained from in situ measurements, whereas other fluxes were calculated with the SMAP model. By examining the components of the SEB, we determined that low-level clouds accompanied by a significant temperature increase played an important role in the melt event observed at SIGMA-A. These conditions induced a remarkable surface heating via cloud radiative forcing in the polar region.

  11. Potential respiration estimated by electron transport system activity in deep-sea suprabenthic crustaceans off Balearic Islands (Western Mediterranean)

    Science.gov (United States)

    Herrera, A.; Gómez, M.; Packard, T. T.; Reglero, P.; Blanco, E.; Barberá-Cebrián, C.

    2014-10-01

    ETS is an acronym for the activity of the respiratory electron transport system; the ETS assay is a biochemical method for estimating the “potential” respiration (Φ). We apply this technique to suprabenthic species captured at three depths (250 m, 650 m and 850 m) in two different locations: Cabrera (Algerian subbasin) and Sóller (Balearic subbasin) during the IDEADOS survey during summer 2010. The aim of this study was to compare specific Φ between areas and between three depths to identify differences in the suprabenthos physiological state related to nutritional conditions. Specific Φ, expressed in unit of μl O2 h- 1 mg prot- 1 was not significantly different between species. Mean values were for the decapods: Plesionika heterocarpus, 8.4 ± 7.9; Gennadas elegans, 8.3 ± 2.9; and Sergestes arcticus 7.3 ± 4.6. Within the euphausiids specific Φ averaged 6.5 ± 4.2 for Thysanopoda aequalis and 9.8 ± 5.1 for Meganyctiphanes norvegica; while for the mysids it ranged from 7.7 ± 4.4 for Boreomysis arctica and 2.1 ± 0.6 for Eucopia unguiculata. The comparison of specific potential respiration (Φ), with the pooling of the data of all the species, showed differences between the two locations, being higher in Cabrera. However, no significant differences between the different depths of each locality were found. The slope of the log Φ-log biomass plot was 0.93 ± 0.09 for Cabrera and 0.64 ± 0.11 in Sóller. We interpret these differences as indicating that the suprabenthos in the Cabrera area, as compared to the Sóller area, has been well-nourished.

  12. Marinomonas profundimaris sp. nov., isolated from deep-sea sediment sample of the Arctic Ocean.

    Science.gov (United States)

    Bai, Xiuhua; Lai, Qiliang; Dong, Chunming; Li, Fuying; Shao, Zongze

    2014-09-01

    A taxonomic study was carried out on strain D104(T), which was isolated from deep-sea subsurface sediment sample from the Arctic Ocean. The bacterium was found to be Gram-negative, oxidase negative and catalase weakly positive, rod shaped, motile by means of polar flagellum. The organism grows between 4 and 37 °C (optimum 25-28 °C) and 0.5-6 % NaCl (optimum 3 %). Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain D104(T) belongs to the genus Marinomonas, with highest sequence similarities of 97.7 % to Marinomonas ushuaiensis DSM 15871(T), followed by M. dokdonensis DSW10-10(T) (96.9 %), M. arenicola KMM 3893(T) (96.7 %), M. arctica 328(T) (96.6 %) and other 18 species of the genus Marinomonas (94.4-96.5 %). The average nucleotide identity and estimated DNA-DNA hybridization values between strain D104(T) and M. ushuaiensis DSM 15871(T) were 84.24 % and 20.80 ± 2.33 % respectively. The principal fatty acids were C16:0, sum in feature 3 (C16:1 ω7c/C16:1 ω6c), sum in feature 8 (C18:1 ω7c/C18:1 ω6c) and C12:1 3OH. The G + C content of the chromosomal DNA was determined to be 44.8 mol%. The respiratory quinone was found to be Q8 (100 %). Polar lipids include phosphatidylglycerol and phosphatidylethanolamine as major phospholipids and aminolipid and phospholipid as minor components. The results of the genotypic and phenotypic analyses indicate that strain D104(T) represents a novel species of the genus Marinomonas, for which the name Marinomonas profundimaris sp. nov. is proposed, with the type strain D104(T) (=MCCC 1A07573(T) = LMG 27696(T)).

  13. Fouling community dominated by Metridium senile (Cnidaria: Anthozoa: Actiniaria in Bahía San Julián (southern Patagonia, Argentina

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    Juan Pablo Martin

    2015-06-01

    Full Text Available The objective of this study is to provide information about a harbour-fouling community dominated by Metridium senile in southern Patagonia. Several steel tubes from the wharf of Puerto San Julián were extracted to perform repair tasks, allowing the attached benthic community to be studied. Sampling was conducted at three levels: lower intertidal, 3-4 m depth and 6-7 m depth. In the lower intertidal, M. senile had a relative abundance of 43%, the most abundant accompanying species being Perumytilus purpuratus, Mytilus edulis platensis and Aulacomya atra atra. At subtidal level, the anemone showed relative abundances of 64% and 65%, and was accompanied by Monocorophium insidiosum at 3-4 m depth and by polychaetes of families Sabellidae and Syllidae at 6-7 m at depth. In the lower intertidal, epibiosis was more frequent on P. purpuratus, A. atra atra and M. edulis platensis, while in the subtidal, the richness of substrate-organisms increased significantly and the anemone was fixed to A. atra atra, M. edulis platensis, Paramolgula gregaria, Crepipatella dilatata, Austromegabalanus psittacus, Hiatella arctica, Polyzoa opuntia, Pyura sp. and Sabellidae tubes. The ability of M. senile to settle on many different organisms, along with other strategies, makes it a colonizer able to displace other species that could compete with it for substratum. Given the cosmopolitan nature of M. senile, the fact that this species has not been previously reported in the coastal zone of the region, and the results of our study, we discuss the possibility that this sea anemone is an invasive alien species in southern Patagonia, or at least a cryptogenic species.

  14. Mercury concentrations in seabird tissues from Machias Seal Island, New Brunswick, Canada

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    Bond, Alexander L., E-mail: abond@mun.ca [Atlantic Cooperative Wildlife Ecology Research Network, University of New Brunswick, PO Box 4400, Fredericton, New Brunswick, E3B 5A3 (Canada); Department of Biology, University of New Brunswick, PO Box 4400, Fredericton, New Brunswick, E3B 5A3 (Canada); Diamond, Antony W. [Atlantic Cooperative Wildlife Ecology Research Network, University of New Brunswick, PO Box 4400, Fredericton, New Brunswick, E3B 5A3 (Canada); Department of Biology, University of New Brunswick, PO Box 4400, Fredericton, New Brunswick, E3B 5A3 (Canada)

    2009-07-01

    Mercury is a pervasive environmental contaminant, the anthropogenic portion of which is increasing globally, and in northeastern North America in particular. Seabirds frequently are used as indicators of the marine environment, including mercury contamination. We analysed paired samples for total mercury (Hg) concentrations in feathers and blood from adult and chick, albumen, and lipid-free yolk of seven seabirds breeding on Machias Seal Island, New Brunswick, Canada - Arctic Tern (Sterna paradisaea), Atlantic Puffin (Fratercula arctica), Common Eider (Somateria mollissima), Common Murre (Uria aalge), Common Tern (Sterna hirundo), Leach's Storm-petrel (Oceanodroma leucorhoa), and Razorbill (Alca torda). We also used stable-isotope ratios of carbon ({delta}{sup 13}C), and nitrogen ({delta}{sup 15}N) to evaluate the relationship between carbon source and trophic position and mercury. We found high Hg concentrations across tissue types in Leach's Storm-petrels, and Razorbills, with lower concentrations in other species, the lowest being in Common Eiders. Storm-petrels prey on mesopelagic fish that accumulate mercury, and Razorbills feed on larger, older fish that bioaccumulate heavy metals. Biomagnification of Hg, or the increase in Hg concentration with trophic position as measured by {delta}{sup 15}N, was significant and greater in albumen than other tissues, whereas in other tissues, {delta}{sup 15}N explained little of the overall variation in Hg concentration. Hg concentrations in egg components are higher on Machias Seal Island than other sites globally and in the Gulf of Maine region, but only for some species. Further detailed investigations are required to determine the cause of this trend.

  15. Distribution of algal aggregates under summer sea ice in the Central Arctic.

    Science.gov (United States)

    Katlein, Christian; Fernández-Méndez, Mar; Wenzhöfer, Frank; Nicolaus, Marcel

    The sea ice cover of the Arctic Ocean has changed dramatically in the last decades, and the resulting consequences for the sea-ice-associated ecosystem remain difficult to assess. Algal aggregates underneath sea ice are of great importance for the ice-associated ecosystem and the pelagic-benthic coupling. However, the frequency and distribution of their occurrence is not well quantified. During the IceArc expedition (ARK-27/3) of RV Polarstern in late summer 2012, we observed different types of algal aggregates floating underneath various ice types in the Central Arctic basins. We investigated the spatial distribution of ice algal aggregates and quantified their biomass, using under-ice image surveys obtained by an upward-looking camera on a remotely operated vehicle. On basin scale, filamentous aggregates of Melosira arctica are more frequently found in the inner part of the Central Arctic pack ice, while rounded aggregates mainly formed by pennate diatoms are found closer to the ice edge, under melting sea ice. On the scale of an ice floe, the distribution of algal aggregates in late summer is mainly regulated by the topography of the ice underside, with aggregates accumulating in dome-shaped structures and at the edges of pressure ridges. The average biomass of the aggregates from our sites and season was 0.1-6.0 mg C m(-2). However, depending on the approach used, differences in orders of magnitude for biomass estimates may occur. This highlights the difficulties of upscaling observations and comparing results from surveys conducted using different methods or on different spatial scales.

  16. Plant co-existence patterns and High-Arctic vegetation composition in three common plant communities in north-east Greenland

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    Oriol Grau

    2014-09-01

    Full Text Available Arctic regions are expected to experience substantial changes in climate in the coming decades. In order to predict potential changes of Arctic vegetation, it is important to understand the distinct role of life forms of plants and of individual species in relation to plant co-existence patterns. Our aim is to investigate if three common Arctic plant patch types dominated by contrasting life forms (by the dwarf shrubs Salix arctica or Dryas octopetala×intermedia or by mosses are related (a to the co-existence of vascular plants and species richness at patch scale and (b to the floristic composition in three distinct plant communities (Salix snowbed, Dryas heath and fell-field associated with contrasting abiotic regimes. The study was conducted at Zackenberg, in north-east Greenland. Dryas patches showed a clear negative effect on small-scale plant richness and co-existence in the fell-field. Salix and moss patches showed a similar pattern in all the plant communities, although the number of individuals growing in Salix patches was lower than in moss patches. Salix and mosses in the fell-fields hosted a high number of species in spite of the much less vegetated aspect of this harsh, upper zone. The floristic composition varied between plant communities, but it did not change substantially between patch types within each community. This study provides novel background knowledge of plant co-existence patterns at patch scale and of the structure of contrasting Arctic plant communities, which will help to better assess the potential effects of varying abiotic stress regimes on Arctic vegetation.

  17. Was the Mediterranean Sea during the Calabrian (Early Pleistocene) a low seasonality environment?

    Science.gov (United States)

    von Leesen, Gotje; Beierlein, Lars; Scarponi, Daniele; Schöne, Bernd R.; Brey, Thomas

    2017-04-01

    Understanding past seasonal temperature variability in the ocean is essential to evaluate the effects of future climate change on marine ecosystems. Here, we estimate seasonal amplitudes and average water temperature from stable oxygen isotope (δ18Oshell) values assuming δ18Owater values of 0.9 ± 0.1‰ (V-SMOV). Fossil valves of the bivalve Arctica islandica were collected from three Pleistocene successions (middle-late Calabrian) in Italy. Biostratigraphic analyses from Tacconi Quarry deposits (Rome) indicate an age between 1.6 and 1.2 Ma, while Augusta and Cutrofiano (Lecce) successions are slightly more recent (1.1 and 0.62 Ma, respectively). Prior to carbonate geochemical analysis, we checked the shells for potential diagenetic alterations (e.g., from aragonite to calcite). Stable oxygen isotope (δ18Oshell) profiles of eleven fossil A. islandica valves all depict a relatively low seasonality scenario. δ18Oshell amplitudes vary between 0.4‰ and 1.1‰ implying a reconstructed seasonal water temperature amplitude of 1.7˚ C to 4.8˚ C. The reconstructed average water temperature for the Sicilian population (i.e., 9 valves) is 9.5 ± 0.47˚ C for δ18Owater 0.9 ± 0.1‰ and coincides well with temperature requirements for modern A. islandica. The low seasonality scenario (ca. 3˚ C) represented by the shells and the low reconstructed water temperatures, colder than modern water temperatures let to the conclusion that the shells lived during a maximum glacial phase when relatively constant water temperatures prevailed throughout the year.

  18. An annually resolved marine proxy record for the 8.2K cold event from the northern North Sea based on bivalve shells

    Science.gov (United States)

    Butler, Paul; Estrella-Martínez, Juan; Scourse, James

    2017-04-01

    The so-called 8.2K cold event is a rapid cooling of about 6° +/- 2° recorded in the Greenland ice core record and thought to be a consequence of a freshwater pulse from the Laurentide ice sheet which reduced deepwater formation in the North Atlantic. In the Greenland ice cores the event is characterized by a maximum extent of 159 years and a central event lasting for 70 years. As discussed by Thomas et al (QSR, 2007), the low resolution and dating uncertainty of much palaeoclimate data makes it difficult to determine the rates of change and causal sequence that characterise the event at different locations. We present here a bivalve shell chronology based on four shells of Arctica islandica from the northern North Sea which (within radiocarbon uncertainty) is coeval with the 8.2K event recorded in the Greenland ice cores. The years of death of each shell based on radiocarbon analysis and crossmatching are 8094, 8134, 8147, and 8208 yrs BP (where "present" = AD 1950), with an associated radiocarbon uncertainty of +/-80 yrs, and their longevities are 106, 122, 112 and 79 years respectively. The total length of the chronology is 192 years (8286 - 8094 BP +/- 80 yrs). The most noticeable feature of the chronology is an 60-year period of increasing growth which may correspond to a similar period of decreasing ice accumulation in the GRIP (central Greenland) ice core record. We tentatively suggest that this reflects increasing food supply to the benthos as summer stratification is weakened by colder seawater temperatures. Stable isotope analyses (results expected to be available when this abstract is presented), will show changes at annual and seasonal resolution, potentially giving a very detailed insight into the causal factors associated with the 8.2K event and its impact in the northern North Sea.

  19. IDENTIFICACIÓN MOLECULAR DE POBLACIONES BACTERIANAS ASOCIADAS AL CARACOL PALA (Strombus gigas DEL CARIBE COLOMBIANO Molecular Identification Of Bacterial Populations Associated To Queen Conch (Strombus gigas From Colombian Caribbe

    Directory of Open Access Journals (Sweden)

    EDINSON ANDRÉS ACOSTA

    Full Text Available El caracol Pala, Strombus gigas (Strombidae, es de gran importancia ecológica y socioeconómica en el área caribeña colombiana. Sin embargo, es una especie catalogada como "vulnerable" y existe muy poca información referente a las especies bacterianas asociadas al caracol que puedan ser importantes para el desarrollo, manejo productivo y de seguridad acuícola de estos gastrópodos. En este trabajo, nosotros empleamos un estudio microbiológico y molecular de la región intergénica entre los genes 16S y 23S rDNA, análisis del gen rDNA 16S y secuenciación, para analizar las bacterias asociadas al caracol Pala (S. gigas. La composición de bacterias cultivables asociadas fue evaluada por su capacidad para crecer en agar marino y en medios de cultivos selectivos. De un total de 28 muestras analizadas encontramos que el número de bacterias cultivadas en condiciones aerobias fue de alrededor 10(6 ufc mL-1 donde las bacterias pertenecientes a la familia Vibrionacea fueron las más abundantes, cerca de >10(5 ufc mL-1. El análisis molecular de la región intergénica entre los genes 16S y 23S rDNA de las diferentes muestras, reveló una gran complejidad bacteriana asociada a S. gigas. Las secuencias de los amplificados del gen rDNA 16S identificó Pseudoalteromonas sp., Halomonas sp., Psycrobacter sp., Cobetia sp., Pseudomonas sp. y Vibrios sp. Nuestros resultados podrían sugerir un rol importante de estas bacterias como componentes de la comunidad asociada al S. gigas. Esta información puede complementar los estudios que se están implementando en los procesos para la conservación y repoblamiento de las poblaciones de S. gigas en Colombia.The Queen Conch, Strombus gigas (Strombidae, is a species of great ecological and socioeconomic importance in the Caribbean area of Colombia. However, it is currently catalogued as "vulnerable"; there is limited information concerning the bacterial species associated with conch and important in the

  20. IDENTIFICACIÓN MOLECULAR DE POBLACIONES BACTERIANAS ASOCIADAS AL CARACOL PALA (Strombus gigas DEL CARIBE COLOMBIANO

    Directory of Open Access Journals (Sweden)

    ROMERO MAGALLY

    2009-08-01

    Full Text Available RESUMEN

    El caracol Pala, Strombus gigas (Strombidae, es de gran importancia ecológica y socioeconómica en el área caribeña colombiana. Sin embargo, es una especie catalogada como “vulnerable” y existe muy poca información referente a las especies bacterianas asociadas al caracol que puedan ser importantes para el desarrollo, manejo productivo y de seguridad acuícola de estos gastrópodos. En este trabajo, nosotros empleamos un estudio microbiológico y molecular de la región intergénica entre los genes 16S y 23S rDNA, análisis del gen rDNA 16S y secuenciación, para analizar las bacterias asociadas al caracol Pala (S. gigas. La composición de bacterias cultivables asociadas fue evaluada por su capacidad para crecer en agar marino y en medios de cultivos selectivos. De un total de 28 muestras analizadas encontramos que el número de bacterias cultivadas en condiciones aerobias fue de alrededor 106 ufc mL-1 donde las bacterias pertenecientes a la familia Vibrionacea fueron las más abundantes, cerca de >105 ufc mL-1 . El análisis molecular de la región intergénica entre los genes 16S y 23S rDNA de las diferentes muestras, reveló una gran complejidad bacteriana asociada a S. gigas. Las secuencias de los amplificados del gen rDNA 16S identificó Pseudoalteromonas sp., Halomonas sp., Psycrobacter sp., Cobetia sp., Pseudomonas sp. y Vibrios sp. Nuestros resultados podrían sugerir un rol importante de estas bacterias como componentes de la comunidad asociada al S. gigas. Esta información puede complementar los estudios que se están implementando en los procesos para la conservación y repoblamiento de las poblaciones de S. gigas en Colombia.

    Palabras clave: Strombus gigas, Caracol pala, Bacteria, Región intergénica 16S-23S, rDNA 16S.

    ABSTRACT

    The Queen Conch, Strombus gigas (Strombidae, is a species of great ecological and socioeconomic importance in the Caribbean area of Colombia

  1. Role of Bacterial Exopolysaccharides (EPS) in the Fate of the Oil Released during the Deepwater Horizon Oil Spill

    Science.gov (United States)

    Gutierrez, Tony; Berry, David; Yang, Tingting; Mishamandani, Sara; McKay, Luke; Teske, Andreas; Aitken, Michael D.

    2013-01-01

    Halomonas species are recognized for producing exopolysaccharides (EPS) exhibiting amphiphilic properties that allow these macromolecules to interface with hydrophobic substrates, such as hydrocarbons. There remains a paucity of knowledge, however, on the potential of Halomonas EPS to influence the biodegradation of hydrocarbons. In this study, the well-characterized amphiphilic EPS produced by Halomonas species strain TG39 was shown to effectively increase the solubilization of aromatic hydrocarbons and enhance their biodegradation by an indigenous microbial community from oil-contaminated surface waters collected during the active phase of the Deepwater Horizon oil spill. Three Halomonas strains were isolated from the Deepwater Horizon site, all of which produced EPS with excellent emulsifying qualities and shared high (97-100%) 16S rRNA sequence identity with strain TG39 and other EPS-producing Halomonas strains. Analysis of pyrosequence data from surface water samples collected during the spill revealed several distinct Halomonas phylotypes, of which some shared a high sequence identity (≥97%) to strain TG39 and the Gulf spill isolates. Other bacterial groups comprising members with well-characterized EPS-producing qualities, such as Alteromonas, Colwellia and Pseudoalteromonas, were also found enriched in surface waters, suggesting that the total pool of EPS in the Gulf during the spill may have been supplemented by these organisms. Roller bottle incubations with one of the Halomonas isolates from the Deepwater Horizon spill site demonstrated its ability to effectively produce oil aggregates and emulsify the oil. The enrichment of EPS-producing bacteria during the spill coupled with their capacity to produce amphiphilic EPS is likely to have contributed to the ultimate removal of the oil and to the formation of oil aggregates, which were a dominant feature observed in contaminated surface waters. PMID:23826336

  2. Marine-Derived Quorum-Sensing Inhibitory Activities Enhance the Antibacterial Efficacy of Tobramycin against Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    Alessandro Busetti

    2014-12-01

    Full Text Available Bacterial epiphytes isolated from marine eukaryotes were screened for the production of quorum sensing inhibitory compounds (QSIs. Marine isolate KS8, identified as a Pseudoalteromonas sp., was found to display strong quorum sensing inhibitory (QSI activity against acyl homoserine lactone (AHL-based reporter strains Chromobacterium violaceum ATCC 12472 and CV026. KS8 supernatant significantly reduced biofilm biomass during biofilm formation (−63% and in pre-established, mature P. aeruginosa PAO1 biofilms (−33%. KS8 supernatant also caused a 0.97-log reduction (−89% and a 2-log reduction (−99% in PAO1 biofilm viable counts in the biofilm formation assay and the biofilm eradication assay respectively. The crude organic extract of KS8 had a minimum inhibitory concentration (MIC of 2 mg/mL against PAO1 but no minimum bactericidal concentration (MBC was observed over the concentration range tested (MBC > 16 mg/mL. Sub-MIC concentrations (1 mg/mL of KS8 crude organic extract significantly reduced the quorum sensing (QS-dependent production of both pyoverdin and pyocyanin in P. aeruginosa PAO1 without affecting growth. A combinatorial approach using tobramycin and the crude organic extract at 1 mg/mL against planktonic P. aeruginosa PAO1 was found to increase the efficacy of tobramycin ten-fold, decreasing the MIC from 0.75 to 0.075 µg/mL. These data support the validity of approaches combining conventional antibiotic therapy with non-antibiotic compounds to improve the efficacy of current treatments.

  3. Spatial and species variations in bacterial communities associated with corals from the Red Sea as revealed by pyrosequencing.

    Science.gov (United States)

    Lee, On On; Yang, Jiangke; Bougouffa, Salim; Wang, Yong; Batang, Zenon; Tian, Renmao; Al-Suwailem, Abdulaziz; Qian, Pei-Yuan

    2012-10-01

    Microbial associations with corals are common and are most likely symbiotic, although their diversity and relationships with environmental factors and host species remain unclear. In this study, we adopted a 16S rRNA gene tag-pyrosequencing technique to investigate the bacterial communities associated with three stony Scleractinea and two soft Octocorallia corals from three locations in the Red Sea. Our results revealed highly diverse bacterial communities in the Red Sea corals, with more than 600 ribotypes detected and up to 1,000 species estimated from a single coral species. Altogether, 21 bacterial phyla were recovered from the corals, of which Gammaproteobacteria was the most dominant group, and Chloroflexi, Chlamydiae, and the candidate phylum WS3 were reported in corals for the first time. The associated bacterial communities varied greatly with location, where environmental conditions differed significantly. Corals from disturbed areas appeared to share more similar bacterial communities, but larger variations in community structures were observed between different coral species from pristine waters. Ordination methods identified salinity and depth as the most influential parameters affecting the abundance of Vibrio, Pseudoalteromonas, Serratia, Stenotrophomonas, Pseudomonas, and Achromobacter in the corals. On the other hand, bacteria such as Chloracidobacterium and Endozoicomonas were more sensitive to the coral species, suggesting that the host species type may be influential in the associated bacterial community, as well. The combined influences of the coral host and environmental factors on the associated microbial communities are discussed. This study represents the first comparative study using tag-pyrosequencing technology to investigate the bacterial communities in Red Sea corals.

  4. Anti-Biofilm Activities from Marine Cold Adapted Bacteria Against Staphylococci and Pseudomonas aeruginosa.

    Science.gov (United States)

    Papa, Rosanna; Selan, Laura; Parrilli, Ermenegilda; Tilotta, Marco; Sannino, Filomena; Feller, Georges; Tutino, Maria L; Artini, Marco

    2015-01-01

    Microbial biofilms have great negative impacts on the world's economy and pose serious problems to industry, public health and medicine. The interest in the development of new approaches for the prevention and treatment of bacterial adhesion and biofilm formation has increased. Since, bacterial pathogens living in biofilm induce persistent chronic infections due to the resistance to antibiotics and host immune system. A viable approach should target adhesive properties without affecting bacterial vitality in order to avoid the appearance of resistant mutants. Many bacteria secrete anti-biofilm molecules that function in regulating biofilm architecture or mediating the release of cells from it during the dispersal stage of biofilm life cycle. Cold-adapted marine bacteria represent an untapped reservoir of biodiversity able to synthesize a broad range of bioactive compounds, including anti-biofilm molecules. The anti-biofilm activity of cell-free supernatants derived from sessile and planktonic cultures of cold-adapted bacteria belonging to Pseudoalteromonas, Psychrobacter, and Psychromonas species were tested against Staphylococcus aureus, Staphylococcus epidermidis, and Pseudomonas aeruginosa strains. Reported results demonstrate that we have selected supernatants, from cold-adapted marine bacteria, containing non-biocidal agents able to destabilize biofilm matrix of all tested pathogens without killing cells. A preliminary physico-chemical characterization of supernatants was also performed, and these analyses highlighted the presence of molecules of different nature that act by inhibiting biofilm formation. Some of them are also able to impair the initial attachment of the bacterial cells to the surface, thus likely containing molecules acting as anti-biofilm surfactant molecules. The described ability of cold-adapted bacteria to produce effective anti-biofilm molecules paves the way to further characterization of the most promising molecules and to test their

  5. Role of Bacterial Exopolysaccharides (EPS) in the Fate of the Oil Released during the Deepwater Horizon Oil Spill.

    Science.gov (United States)

    Gutierrez, Tony; Berry, David; Yang, Tingting; Mishamandani, Sara; McKay, Luke; Teske, Andreas; Aitken, Michael D

    2013-01-01

    Halomonas species are recognized for producing exopolysaccharides (EPS) exhibiting amphiphilic properties that allow these macromolecules to interface with hydrophobic substrates, such as hydrocarbons. There remains a paucity of knowledge, however, on the potential of Halomonas EPS to influence the biodegradation of hydrocarbons. In this study, the well-characterized amphiphilic EPS produced by Halomonas species strain TG39 was shown to effectively increase the solubilization of aromatic hydrocarbons and enhance their biodegradation by an indigenous microbial community from oil-contaminated surface waters collected during the active phase of the Deepwater Horizon oil spill. Three Halomonas strains were isolated from the Deepwater Horizon site, all of which produced EPS with excellent emulsifying qualities and shared high (97-100%) 16S rRNA sequence identity with strain TG39 and other EPS-producing Halomonas strains. Analysis of pyrosequence data from surface water samples collected during the spill revealed several distinct Halomonas phylotypes, of which some shared a high sequence identity (≥97%) to strain TG39 and the Gulf spill isolates. Other bacterial groups comprising members with well-characterized EPS-producing qualities, such as Alteromonas, Colwellia and Pseudoalteromonas, were also found enriched in surface waters, suggesting that the total pool of EPS in the Gulf during the spill may have been supplemented by these organisms. Roller bottle incubations with one of the Halomonas isolates from the Deepwater Horizon spill site demonstrated its ability to effectively produce oil aggregates and emulsify the oil. The enrichment of EPS-producing bacteria during the spill coupled with their capacity to produce amphiphilic EPS is likely to have contributed to the ultimate removal of the oil and to the formation of oil aggregates, which were a dominant feature observed in contaminated surface waters.

  6. Effect of fumigation with chloropicrin on soil bacterial communities and genes encoding key enzymes involved in nitrogen cycling.

    Science.gov (United States)

    Li, Jun; Huang, Bin; Wang, Qiuxia; Li, Yuan; Fang, Wensheng; Yan, Dongdong; Guo, Meixia; Cao, Aocheng

    2017-08-01

    Chloropicrin (CP) is a potential alternative for methyl bromide as a soil fumigant given that the use of methyl bromide has become limited. However, little is known about how fumigation with CP affects the condition of the soil microbial community. In this study, 16S rRNA amplicon sequencing and quantitative PCR were combined to investigate the effect of CP on soil bacterial community. In total, 938,922 effective reads were obtained from 18 samples and clustered into 58,662 operational taxonomic units at a similarity cut-off of 97%. Both approaches showed that the primary structure of bacterial community in soil did not significantly change at the phylum level after fumigation, but CP had a significant impact on the abundance of the bacterial microbiome that was recovered and identified. Additionally, bacterial community diversity decreased significantly, and there was a shift in the predominant populations. Staphylococcus, Actinomadura, Acinetobacter and Streptomyces significantly decreased in number or disappeared, and Bacteroides, Lachnoclostridium, Pseudoalteromonas, Colwellia, Idiomarina and Cobetia became the new predominant populations. In addition, some species associated with biodegradation, such as Sphingomonas spp. and Rhodococcus spp., significantly increased in number. The abundance of ammonia-oxidizing archaea (AOA) were significantly inhibited, yet the abundance of ammonia-oxidizing bacteria (AOB) significantly increased, and denitrification was significantly promoted. These changes in bacterial flora can considerably impact soil function and health and lead to negative effects on the environment surrounding fumigated soils, indicating the need for proactive risk management. Our study provides useful information for environmental safety assessments of CP in China. Copyright © 2017. Published by Elsevier Ltd.

  7. Microbial community structure and function on sinking particles in the North Pacific Subtropical Gyre

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    Kristina M. Fontanez

    2015-05-01

    Full Text Available Sinking particles mediate the transport of carbon and energy to the deep-sea, yet the specific microbes associated with sedimenting particles in the ocean’s interior remain largely uncharacterized. In this study, we used particle interceptor traps (PITs to assess the nature of particle-associated microbial communities collected at a variety of depths in the North Pacific Subtropical Gyre. Comparative metagenomics was used to assess differences in microbial taxa and functional gene repertoires in PITs containing a preservative (poisoned traps compared to preservative-free traps where growth was allowed to continue in situ (live traps. Live trap microbial communities shared taxonomic and functional similarities with bacteria previously reported to be enriched in dissolved organic matter (DOM microcosms (e.g., Alteromonas and Methylophaga, in addition to other particle and eukaryote-associated bacteria (e.g., Flavobacteriales and Pseudoalteromonas. Poisoned trap microbial assemblages were enriched in Vibrio and Campylobacterales likely associated with eukaryotic surfaces and intestinal tracts as symbionts, pathogens or saprophytes. The functional gene content of microbial assemblages in poisoned traps included a variety of genes involved in virulence, anaerobic metabolism, attachment to chitinaceaous surfaces, and chitin degradation. The presence of chitinaceaous surfaces was also accompanied by the co-existence of bacteria which encoded the capacity to attach to, transport and metabolize chitin and its derivatives. Distinctly different microbial assemblages predominated in live traps, which were largely represented by copiotrophs and eukaryote-associated bacterial communities. These data indicate the central role of eukaryotic taxa in structuring sinking particle microbial assemblages, as well as the rapid responses of indigenous microbial species in the degradation of marine particulate organic matter in situ in the ocean’s interior.

  8. Indigenous oil-degrading bacteria in crude oil-contaminated seawater of the Yellow sea, China.

    Science.gov (United States)

    Wang, Wanpeng; Zhang, Rongqiu; Zhong, Rongqiu; Shan, Dapeng; Shao, Zongze

    2014-08-01

    Indigenous oil-degrading bacteria play an important role in efficient remediation of polluted marine environments. In this study, we investigated the diversity and abundance of indigenous oil-degrading bacteria and functional genes in crude oil-contaminated seawater of the Dalian coast. The gene copy number bacterial 16S rRNA in total were determined to be about 10(10) copies L(-1) in contaminated seawater and 10(9) copies L(-1) in uncontaminated seawater. Bacteria of Alcanivorax, Marinobacter, Novosphingobium, Rhodococcus, and Pseudoalteromonas were found to be predominant oil-degrading bacteria in the polluted seawater in situ. In addition, bacteria belonging to Algoriphagus, Aestuariibacter, Celeribacter, Fabibacter, Zobellia, Tenacibaculum, Citreicella, Roseivirga, Winogradskyella, Thioclava, Polaribacter, and Pelagibaca were confirmed to be the first time as an oil-degrading bacterium. The indigenous functional enzymes, including AlkB or polycyclic aromatic hydrocarbons ring-hydroxylating dioxygenases α (PAH-RHDα) coding genes from Gram-positive (GP) and Gram-negative bacteria (GN), were revealed and quite diverse. About 10(10) to 10(11) copies L(-1) for the expression of alkB genes were recovered and showed that the two-thirds of all the AlkB sequences were closely related to widely distributed Alcanivorax and Marinobacter isolates. About 10(9) copies L(-1) seawater for the expression of RHDαGN genes in contaminated seawater and showed that almost all RHDαGN sequences were closely related to an uncultured bacterium; however, RHDαGP genes represented only about 10(5) copies L(-1) seawater for the expression of genes in contaminated seawater, and the naphthalene dioxygenase sequences from Rhodococcus and Mycobacterium species were most abundant. Together, their data provide evidence that there exists an active aerobic microbial community indigenous to the coastal area of the Yellow sea that is capable of degrading petroleum hydrocarbons.

  9. Comparative analysis of bacterial community-metagenomics in coastal Gulf of Mexico sediment microcosms following exposure to Macondo oil (MC252)

    KAUST Repository

    Koo, Hyunmin

    2014-09-10

    The indigenous bacterial communities in sediment microcosms from Dauphin Island (DI), Petit Bois Island (PB) and Perdido Pass (PP) of the coastal Gulf of Mexico were compared following treatment with Macondo oil (MC252) using pyrosequencing and culture-based approaches. After quality-based trimming, 28,991 partial 16S rRNA sequence reads were analyzed by rarefaction, confirming that analyses of bacterial communities were saturated with respect to species diversity. Changes in the relative abundances of Proteobacteria, Bacteroidetes and Firmicutes played an important role in structuring bacterial communities in oil-treated sediments. Proteobacteria were dominant in oil-treated samples, whereas Firmicutes and Bacteroidetes were either the second or the third most abundant taxa. Tenericutes, members of which are known for oil biodegradation, were detected shortly after treatment, and continued to increase in DI and PP sediments. Multivariate statistical analyses (ADONIS) revealed significant dissimilarity of bacterial communities between oil-treated and untreated samples and among locations. In addition, a similarity percentage analysis showed the contribution of each species to the contrast between untreated and oil-treated samples. PCR amplification using DNA from pure cultures of Exiguobacterium,  Pseudoalteromonas,  Halomonas and Dyadobacter, isolated from oil-treated microcosm sediments, produced amplicons similar to polycyclic aromatic hydrocarbon-degrading genes. In the context of the 2010 Macondo blowout, the results from our study demonstrated that the indigenous bacterial communities in coastal Gulf of Mexico sediment microcosms responded to the MC252 oil with altered community structure and species composition. The rapid proliferation of hydrocarbonoclastic bacteria suggests their involvement in the degradation of the spilt oil in the Gulf of Mexico ecosystem.

  10. Macroalgal Morphogenesis Induced by Waterborne Compounds and Bacteria in Coastal Seawater

    Science.gov (United States)

    Grueneberg, Jan; Engelen, Aschwin H.; Costa, Rodrigo; Wichard, Thomas

    2016-01-01

    Axenic gametes of the marine green macroalga Ulva mutabilis Føyn (Ria Formosa, locus typicus) exhibit abnormal development into slow-growing callus-like colonies with aberrant cell walls. Under laboratory conditions, it was previously demonstrated that all defects in growth and thallus development can be completely abolished when axenic gametes are inoculated with a combination of two specific bacterial strains originally identified as Roseobacter sp. strain MS2 and Cytophaga sp. strain MS6. These bacteria release diffusible morphogenetic compounds (= morphogens), which act similar to cytokinin and auxin. To investigate the ecological relevance of the waterborne bacterial morphogens, seawater samples were collected in the Ria Formosa lagoon (Algarve, Southern Portugal) at 20 sampling sites and tidal pools to assess their morphogenetic effects on the axenic gametes of U. mutabilis. Specifically the survey revealed that sterile-filtered seawater samples can completely recover growth and morphogenesis of U. mutabilis under axenic conditions. Morphogenetic activities of free-living and epiphytic bacteria isolated from the locally very abundant Ulva species (i.e., U. rigida) were screened using a multiwell-based testing system. The most represented genera isolated from U. rigida were Alteromonas, Pseudoalteromonas and Sulfitobacter followed by Psychrobacter and Polaribacter. Several naturally occurring bacterial species could emulate MS2 activity (= induction of cell divisions) regardless of taxonomic affiliation, whereas the MS6 activity (= induction of cell differentiation and cell wall formation) was species-specific and is probably a feature of difficult-to-culture bacteria. Interestingly, isolated bacteroidetes such as Algoriphagus sp. and Polaribacter sp. could individually trigger complete Ulva morphogenesis and thus provide a novel mode of action for bacterial-induced algal development. This study also highlights that the accumulation of algal growth factors in

  11. Hydrocarbon-degrading bacteria enriched by the Deepwater Horizon oil spill identified by cultivation and DNA-SIP

    Science.gov (United States)

    Gutierrez, Tony; Singleton, David R; Berry, David; Yang, Tingting; Aitken, Michael D; Teske, Andreas

    2013-01-01

    The massive influx of crude oil into the Gulf of Mexico during the Deepwater Horizon (DWH) disaster triggered dramatic microbial community shifts in surface oil slick and deep plume waters. Previous work had shown several taxa, notably DWH Oceanospirillales, Cycloclasticus and Colwellia, were found to be enriched in these waters based on their dominance in conventional clone and pyrosequencing libraries and were thought to have had a significant role in the degradation of the oil. However, this type of community analysis data failed to provide direct evidence on the functional properties, such as hydrocarbon degradation of organisms. Using DNA-based stable-isotope probing with uniformly 13C-labelled hydrocarbons, we identified several aliphatic (Alcanivorax, Marinobacter)- and polycyclic aromatic hydrocarbon (Alteromonas, Cycloclasticus, Colwellia)-degrading bacteria. We also isolated several strains (Alcanivorax, Alteromonas, Cycloclasticus, Halomonas, Marinobacter and Pseudoalteromonas) with demonstrable hydrocarbon-degrading qualities from surface slick and plume water samples collected during the active phase of the spill. Some of these organisms accounted for the majority of sequence reads representing their respective taxa in a pyrosequencing data set constructed from the same and additional water column samples. Hitherto, Alcanivorax was not identified in any of the previous water column studies analysing the microbial response to the spill and we discuss its failure to respond to the oil. Collectively, our data provide unequivocal evidence on the hydrocarbon-degrading qualities for some of the dominant taxa enriched in surface and plume waters during the DWH oil spill, and a more complete understanding of their role in the fate of the oil. PMID:23788333

  12. Changes in bacterial community metabolism and composition during the degradation of dissolved organic matter from the jellyfish Aurelia aurita in a Mediterranean coastal lagoon.

    Science.gov (United States)

    Blanchet, Marine; Pringault, Olivier; Bouvy, Marc; Catala, Philippe; Oriol, Louise; Caparros, Jocelyne; Ortega-Retuerta, Eva; Intertaglia, Laurent; West, Nyree; Agis, Martin; Got, Patrice; Joux, Fabien

    2015-09-01

    Spatial increases and temporal shifts in outbreaks of gelatinous plankton have been observed over the past several decades in many estuarine and coastal ecosystems. The effects of these blooms on marine ecosystem functioning and particularly on the dynamics of the heterotrophic bacteria are still unclear. The response of the bacterial community from a Mediterranean coastal lagoon to the addition of dissolved organic matter (DOM) from the jellyfish Aurelia aurita, corresponding to an enrichment of dissolved organic carbon (DOC) by 1.4, was assessed for 22 days in microcosms (8 l). The high bioavailability of this material led to (i) a rapid mineralization of the DOC and dissolved organic nitrogen from the jellyfish and (ii) the accumulation of high concentrations of ammonium and orthophosphate in the water column. DOM from jellyfish greatly stimulated heterotrophic prokaryotic production and respiration rates during the first 2 days; then, these activities showed a continuous decay until reaching those measured in the control microcosms (lagoon water only) at the end of the experiment. Bacterial growth efficiency remained below 20%, indicating that most of the DOM was respired and a minor part was channeled to biomass production. Changes in bacterial diversity were assessed by tag pyrosequencing of partial bacterial 16S rRNA genes, DNA fingerprints, and a cultivation approach. While bacterial diversity in control microcosms showed little changes during the experiment, the addition of DOM from the jellyfish induced a rapid growth of Pseudoalteromonas and Vibrio species that were isolated. After 9 days, the bacterial community was dominated by Bacteroidetes, which appeared more adapted to metabolize high-molecular-weight DOM. At the end of the experiment, the bacterial community shifted toward a higher proportion of Alphaproteobacteria. Resilience of the bacterial community after the addition of DOM from the jellyfish was higher for metabolic functions than diversity

  13. Plant carbohydrate scavenging through tonB-dependent receptors: a feature shared by phytopathogenic and aquatic bacteria.

    Directory of Open Access Journals (Sweden)

    Servane Blanvillain

    Full Text Available TonB-dependent receptors (TBDRs are outer membrane proteins mainly known for the active transport of iron siderophore complexes in Gram-negative bacteria. Analysis of the genome of the phytopathogenic bacterium Xanthomonas campestris pv. campestris (Xcc, predicts 72 TBDRs. Such an overrepresentation is common in Xanthomonas species but is limited to only a small number of bacteria. Here, we show that one Xcc TBDR transports sucrose with a very high affinity, suggesting that it might be a sucrose scavenger. This TBDR acts with an inner membrane transporter, an amylosucrase and a regulator to utilize sucrose, thus defining a new type of carbohydrate utilization locus, named CUT locus, involving a TBDR for the transport of substrate across the outer membrane. This sucrose CUT locus is required for full pathogenicity on Arabidopsis, showing its importance for the adaptation to host plants. A systematic analysis of Xcc TBDR genes and a genome context survey suggested that several Xcc TBDRs belong to other CUT loci involved in the utilization of various plant carbohydrates. Interestingly, several Xcc TBDRs and CUT loci are conserved in aquatic bacteria such as Caulobacter crescentus, Colwellia psychrerythraea, Saccharophagus degradans, Shewanella spp., Sphingomonas spp. or Pseudoalteromonas spp., which share the ability to degrade a wide variety of complex carbohydrates and display TBDR overrepresentation. We therefore propose that TBDR overrepresentation and the presence of CUT loci designate the ability to scavenge carbohydrates. Thus CUT loci, which seem to participate to the adaptation of phytopathogenic bacteria to their host plants, might also play a very important role in the biogeochemical cycling of plant-derived nutrients in marine environments. Moreover, the TBDRs and CUT loci identified in this study are clearly different from those characterized in the human gut symbiont Bacteroides thetaiotaomicron, which allow glycan foraging

  14. Control of biofouling by xanthine oxidase on seawater reverse osmosis membranes from a desalination plant: enzyme production and screening of bacterial isolates from the full-scale plant.

    Science.gov (United States)

    Nagaraj, V; Skillman, L; Li, D; Xie, Z; Ho, G

    2017-07-01

    Control of biofouling on seawater reverse osmosis (SWRO) membranes is a major challenge as treatments can be expensive, damage the membrane material and often biocides do not remove the polymers in which bacteria are embedded. Biological control has been largely ignored for biofouling control. The objective of this study was to demonstrate the effectiveness of xanthine oxidase enzyme against complex fouling communities and then identify naturally occurring bacterial strains that produce the free radical generating enzyme. Initially, 64 bacterial strains were isolated from different locations of the Perth Seawater Desalination Plant. In our preceding study, 25/64 isolates were selected from the culture collection as models for biofouling studies, based on their prevalence in comparison to the genomic bacterial community. In this study, screening of these model strains was performed using a nitroblue tetrazolium assay in the presence of hypoxanthine as substrate. Enzyme activity was measured by absorbance. Nine of 25 strains tested positive for xanthine oxidase production, of which Exiguobacterium from sand filters and Microbacterium from RO membranes exhibited significant levels of enzyme production. Other genera that produced xanthine oxidase were Marinomonas, Pseudomonas, Bacillus, Pseudoalteromonas and Staphylococcus. Strain variations were observed between members of the genera Microbacterium and Bacillus. Xanthine oxidase, an oxidoreductase enzyme that generates reactive oxygen species, is endogenously produced by many bacterial species. In this study, production of the enzyme by bacterial isolates from a full-scale desalination plant was investigated for potential use as biological control of membrane fouling in seawater desalination. We have previously demonstrated that free radicals generated by a commercially available xanthine oxidase in the presence of a hypoxanthine substrate, effectively dispersed biofilm polysaccharides on industrially fouled membranes

  15. Bacterial Infochemicals are Drivers of Algal Lysis

    Science.gov (United States)

    Whalen, K.; Deering, R.; Rowley, D. C.; El Gamal, A.; Schorn, M.; Moore, B. S.; Johnson, M. D.; Mincer, T. J.; Harvey, E.

    2016-02-01

    Processing of organic matter by bacteria forces oceanic biogeochemical cycles, food web structure and ultimately environmental stoichiometry. A newly emerging picture of the microbial loop suggests that bacteria are not merely passive recipients of dissolved organic matter (DOM) from phytoplankton exudate. Rather, heterotrophic bacteria can mediate the flow of DOM by actively producing soluble algicidal compounds. However, deciphering those chemical signals that determine these interactions has remained a challenge. Here, we report the isolation of 2-heptyl-4-quinolone (HHQ), released by Pseudoalteromonas piscicida, a marine gamma-proteobacteria isolated from plastic debris in the North Atlantic. Both 2-heptyl-3-hydroxy-4-quinolone and its immediate precursor, HHQ are known to function as antibiotics and quorum sensing signaling molecules with crucial roles in virulence, and apoptosis in eukaryotic cells (e.g. fungi and mammalian cells). Our ecologically-relevant screening of live cells and filtrate from P. piscicida cultures caused a significant decrease in the growth rate of the bloom-forming coccolithophore, Emiliania huxleyi. Bioassay-guided fraction of P. piscicida extracellular crude extracts identified HHQ, which induced mortality in three strains of E. huxleyi with an IC50 in the nanomolar range. In contrast, the marine chlorophyte, Dunaliella tertiolecta and diatom, Phaeodactylum tricornutum were unaffected by HHQ exposures (IC50 > 10 micromolar), but were susceptible to extracts of P. piscicida, indicating this bacterium may produce a cocktail of algicidal compounds specific to different phytoplankton guilds. The ability of HHQ to influence phytoplankton growth suggests that alkylquinolone-signaling molecules play a fundamental role in interkingdom interactions, ultimately influencing shifts in phytoplankton population dynamics. This study implicates a new role for HHQ beyond its importance in quorum sensing.

  16. Molecular insights into cold active polygalacturonase enzyme for its potential application in food processing.

    Science.gov (United States)

    Ramya, L N; Pulicherla, K K

    2015-09-01

    Pectin is a complex structural heteropolysaccharide that require numerous pectinolytic enzymes for its complete degradation. Polygalacturonase from mesophilic or thermophilic origin are being widely used in fruit and vegetable processing in the recent decades to degrade pectic substances. Recently cold active pectinases are finding added advantages over meso and thermophilic counterparts, to use in industrial scale particularly in food processing industry. They facilitate in conservation of several properties of foods so that the end product retains its naturality and also generates economic benefits. In the present study, Pseudoalteromonas haloplanktis, a well reported marine psychrophile is taken as a model organism for cold active polygalacturonase and is evaluated in comparision to the routinely used mesophilic and thermophilic enzymes by insicio approach. Polygalacturonase sequences from industrially important microbial sources were subjected to MEME and Pfam wherein motifs and domains involved in the conservation were analyzed. Dendrogram revealed sequence level similarity and motifs showed uniform distribution of conserved regions that are involved in important functions. It was also observed through clustalW analysis that the amount of arginine content of psychrophiles is less when compared with thermophiles. Finally, all the modeled enzyme structures were subjected to docking studies using Autodock 4.2 with the substrate polygalacturonic acid and binding energies were found to be -5.73, -6.22 and -7.27 KCals/mole for meso, thermo and psychrophiles respectively which indicates the efficiency of psychrophilic enzymes when compared with its counterparts giving scope for further experimentation to find their better usage in various food industry applications.

  17. The skin microbiome of the common thresher shark (Alopias vulpinus) has low taxonomic and gene function β-diversity.

    Science.gov (United States)

    Doane, Michael P; Haggerty, John Matthew; Kacev, Dovi; Papudeshi, Bhavya; Dinsdale, Elizabeth A

    2017-08-01

    The health of sharks, like all organisms, is linked to their microbiome. At the skin interface, sharks have dermal denticles that protrude above the mucus, which may affect the types of microbes that occur here. We characterized the microbiome from the skin of the common thresher shark (Alopias vulpinus) to investigate the structure and composition of the skin microbiome. On average 618 812 (80.9% ± S.D. 0.44%) reads per metagenomic library contained open reading frames; of those, between 7.6% and 12.8% matched known protein sequences. Genera distinguishing the A. vulpinus microbiome from the water column included, Pseudoalteromonas (12.8% ± 4.7 of sequences), Erythrobacter (5. 3% ± 0.5) and Idiomarina (4.2% ± 1.2) and distinguishing gene pathways included, cobalt, zinc and cadmium resistance (2.2% ± 0.1); iron acquisition (1.2% ± 0.1) and ton/tol transport (1.3% ± 0.08). Taxonomic community overlap (100 - dissimilarity index) was greater in the skin microbiome (77.6), relative to the water column microbiome (70.6) and a reference host-associated microbiome (algae: 71.5). We conclude the A. vulpinus skin microbiome is influenced by filtering processes, including biochemical and biophysical components of the shark skin and result in a structured microbiome. © 2017 The Authors. Environmental Microbiology published by Society for Applied Microbiology and John Wiley & Sons Ltd.

  18. Microbiota of wild-caught Red Snapper Lutjanus campechanus.

    Science.gov (United States)

    Tarnecki, Andrea M; Patterson, William F; Arias, Covadonga R

    2016-10-21

    The microbiota plays an essential role in host health, particularly through competition with opportunistic pathogens. Changes in total bacterial load and microbiota structure can indicate early stages of disease, and information on the composition of bacterial communities is essential to understanding fish health. Although Red Snapper (Lutjanus campechanus) is an economically important species in recreational fisheries and a primary aquaculture candidate, no information is available on the microbial communities of this species. The aim of this study was to survey the microbiota of apparently healthy, wild-caught Red Snapper from the Gulf of Mexico. Sampled Red Snapper showed no physical signs of disease. Tissues that are either primary entry routes for pathogens (feces, gill) or essential to disease diagnosis (blood) were sampled. Bacteria were enumerated using culture-based techniques and characterized by pyrosequencing. Aerobic counts of feces and gill samples were 10(7) and 10(4) CFU g(-1), respectively. All individuals had positive blood cultures with counts up to 23 CFU g(-1). Gammaproteobacteria dominated the microbiota of all sample types, including the genera Pseudoalteromonas and Photobacterium in feces and Pseudomonas in blood and gill. Gill samples were also dominated by Vibrio while blood samples had high abundances of Nevskia. High variability in microbiota composition was observed between individuals, with percent differences in community composition ranging from 6 to 76 % in feces, 10 to 58 % in gill, and 52 to 64 % in blood. This study provides the first characterization of the microbiota of the economically significant Red Snapper via pyrosequencing. Its role in fish health highlights the importance of understanding microbiota composition for future work on disease prevention using microbial manipulation.

  19. Role of Bacterial Exopolysaccharides (EPS in the Fate of the Oil Released during the Deepwater Horizon Oil Spill.

    Directory of Open Access Journals (Sweden)

    Tony Gutierrez

    Full Text Available Halomonas species are recognized for producing exopolysaccharides (EPS exhibiting amphiphilic properties that allow these macromolecules to interface with hydrophobic substrates, such as hydrocarbons. There remains a paucity of knowledge, however, on the potential of Halomonas EPS to influence the biodegradation of hydrocarbons. In this study, the well-characterized amphiphilic EPS produced by Halomonas species strain TG39 was shown to effectively increase the solubilization of aromatic hydrocarbons and enhance their biodegradation by an indigenous microbial community from oil-contaminated surface waters collected during the active phase of the Deepwater Horizon oil spill. Three Halomonas strains were isolated from the Deepwater Horizon site, all of which produced EPS with excellent emulsifying qualities and shared high (97-100% 16S rRNA sequence identity with strain TG39 and other EPS-producing Halomonas strains. Analysis of pyrosequence data from surface water samples collected during the spill revealed several distinct Halomonas phylotypes, of which some shared a high sequence identity (≥97% to strain TG39 and the Gulf spill isolates. Other bacterial groups comprising members with well-characterized EPS-producing qualities, such as Alteromonas, Colwellia and Pseudoalteromonas, were also found enriched in surface waters, suggesting that the total pool of EPS in the Gulf during the spill may have been supplemented by these organisms. Roller bottle incubations with one of the Halomonas isolates from the Deepwater Horizon spill site demonstrated its ability to effectively produce oil aggregates and emulsify the oil. The enrichment of EPS-producing bacteria during the spill coupled with their capacity to produce amphiphilic EPS is likely to have contributed to the ultimate removal of the oil and to the formation of oil aggregates, which were a dominant feature observed in contaminated surface waters.

  20. Impaired Performance of Pressure-Retarded Osmosis due to Irreversible Biofouling.

    Science.gov (United States)

    Bar-Zeev, Edo; Perreault, François; Straub, Anthony P; Elimelech, Menachem

    2015-11-03

    Next-generation pressure-retarded osmosis (PRO) approaches aim to harness the energy potential of streams with high salinity differences, such as wastewater effluent and seawater desalination plant brine. In this study, we evaluated biofouling propensity in PRO. Bench-scale experiments were carried out for 24 h using a model wastewater effluent feed solution and simulated seawater desalination brine pressurized to 24 bar. For biofouling tests, wastewater effluent was inoculated with Pseudomonas aeruginosa and artificial seawater desalination plant brine draw solution was seeded with Pseudoalteromonas atlantica. Our results indicate that biological growth in the feed wastewater stream channel severely fouled both the membrane support layer and feed spacer, resulting in ∼50% water flux decline. We also observed an increase in the pumping pressure required to force water through the spacer-filled feed channel, with pressure drop increasing from 6.4±0.8 bar m(-1) to 15.1±2.6 bar m(-1) due to spacer blockage from the developing biofilm. Neither the water flux decline nor the increased pressure drop in the feed channel could be reversed using a pressure-aided osmotic backwash. In contrast, biofouling in the seawater brine draw channel was negligible. Overall, the reduced performance due to water flux decline and increased pumping energy requirements from spacer blockage highlight the serious challenges of using high fouling potential feed sources in PRO, such as secondary wastewater effluent. We conclude that PRO power generation using wastewater effluent and seawater desalination plant brine may become possible only with rigorous pretreatment or new spacer and membrane designs.

  1. BAKTERI PROBIOTIK DALAM BUDIDAYA UDANG: SELEKSI, MEKANISME AKSI, KARAKTERISASI, DAN APLIKASINYA SEBAGAI AGEN BIOKONTROL

    Directory of Open Access Journals (Sweden)

    Widanarni

    2008-08-01

    Full Text Available Bacterial disease attack occurs at the hatchery stage, which is considered to be the most serious threat, and often results in mass mortality of shrimp larvae by vibrosis which is that caused by a luminous bacterium identified as Vibrio harveyi. This research was carried out to obtain local isolates of probiotic bacteria that were able to inhibit the growth of V. harveyi and effectively apply it as a biocontrol of vibriosis in shrimp cultures. The research was carried out as follows: (1 In vitro and in vivo selection of probiotic bacteria candidates, (2 Study of the action mechanism and characterization of the selected pro biotic bacteria, (3 Study on application of the selected probiotic bacteria as a biocontrol agent in shrimp cultures. Results of in vitro and in vivo selection provided the best three isolates, which were 1Ub, SKT-b and Ua. The survival rate of shrimp larvae which were not only inoculated by V. harveyi but also with 1Ub, SKT-b and Ua probiotic bacteria were 88.33, 83.33, and 81.67% respectively; where as the positive control treatment (merely inoculated with V. harveyi gave a 41.67% survival rate and the negative control (without bacterial addition was 68.33%. Studies using a rifampicin resistant marker (RfR demonstrated that the number of V. harveyi MR5339 RfR cells in treatments without probiotic addition were higher than the treatment with the probiotic bacteria, in dead larvae, living larvae, as well as in the culture media. Partial sequencing of the I6S-rRNA gene showed that the I Ub isolate was similar to Pseudoalteromonas piscicida, whereas the SKT -b and Ua isolates were similar to Vibrio alginolyticus. Selected probiotic bacteria could be applied directly to shrimp larva culture media, or orally through enrichment of both natural and artificial food

  2. Microbial Successions and Metabolite Changes during Fermentation of Salted Shrimp (Saeu-Jeot) with Different Salt Concentrations

    Science.gov (United States)

    Lee, Se Hee; Jung, Ji Young; Jeon, Che Ok

    2014-01-01

    To investigate the effects of salt concentration on saeu-jeot (salted shrimp) fermentation, four sets of saeu-jeot samples with 20%, 24%, 28%, and 32% salt concentrations were prepared, and the pH, bacterial and archaeal abundances, bacterial communities, and metabolites were monitored during the entire fermentation period. Quantitative PCR showed that Bacteria were much more abundant than Archaea in all saeu-jeot samples, suggesting that bacterial populations play more important roles than archaeal populations even in highly salted samples. Community analysis indicated that Vibrio, Photobacterium, Psychrobacter, Pseudoalteromonas, and Enterovibrio were identified as the initially dominant genera, and the bacterial successions were significantly different depending on the salt concentration. During the early fermentation period, Salinivibrio predominated in the 20% salted samples, whereas Staphylococcus, Halomonas, and Salimicrobium predominated in the 24% salted samples; eventually, Halanaerobium predominated in the 20% and 24% salted samples. The initially dominant genera gradually decreased as the fermentation progressed in the 28% and 32% salted samples, and eventually Salimicrobium became predominant in the 28% salted samples. However, the initially dominant genera still remained until the end of fermentation in the 32% salted samples. Metabolite analysis showed that the amino acid profile and the initial glycerol increase were similar in all saeu-jeot samples regardless of the salt concentration. After 30–80 days of fermentation, the levels of acetate, butyrate, and methylamines in the 20% and 24% salted samples increased with the growth of Halanaerobium, even though the amino acid concentrations steadily increased until approximately 80–107 days of fermentation. This study suggests that a range of 24–28% salt concentration in saeu-jeot fermentation is appropriate for the production of safe and tasty saeu-jeot. PMID:24587230

  3. Biofouling on Reservoir in Sea Water

    Science.gov (United States)

    Yoon, H.; Eom, C.; Kong, M.; Park, Y.; Chung, K.; Kim, B.

    2011-12-01

    The organisms which take part in marine biofouling are primarily the attached or sessile forms occurring naturally in the shallower water along the coast [1]. This is mainly because only those organisms with the ability to adapt to the new situations created by man can adhere firmly enough to avoid being washed off. Chemical and microbiological characteristics of the fouling biofilms developed on various surfaces in contact with the seawater were made. The microbial compositions of the biofilm communities formed on the reservoir polymer surfaces were tested for. The quantities of the diverse microorganisms in the biofilm samples developed on the prohibiting polymer reservoir surface were larger when there was no concern about materials for special selection for fouling. To confirm microbial and formation of biofilm on adsorbents was done CLSM (Multi-photon Confocal Laser Scanning Microscope system) analysis. Microbial identified using 16S rRNA. Experiment results, five species which are Vibrio sp., Pseudoalteromonas, Marinomonas, Sulfitobacter, and Alteromonas discovered to reservoir formed biofouling. There are some microorganism cause fouling and there are the others control fouling. The experimental results offered new specific information, concerning the problems in the application of new material as well as surface coating such as anti-fouling coatings. They showed the important role microbial activity in fouling and corrosion of the surfaces in contact with the any seawater. Acknowledgement : This research was supported by the national research project titled "The Development of Technology for Extraction of Resources Dissolved in Seawater" of the Korea Institute of Geoscience and Mineral Resources (KIGAM) funded by the Ministry of Land, Transport and Maritime Affairs. References [1] M. Y. Diego, K. Soren, and D. J. Kim. Prog. Org. Coat. 50, (2004) p.75-104.

  4. Brine assemblages of ultrasmall microbial cells within the ice cover of Lake Vida, Antarctica.

    Science.gov (United States)

    Kuhn, Emanuele; Ichimura, Andrew S; Peng, Vivian; Fritsen, Christian H; Trubl, Gareth; Doran, Peter T; Murray, Alison E

    2014-06-01

    The anoxic and freezing brine that permeates Lake Vida's perennial ice below 16 m contains an abundance of very small (≤0.2-μm) particles mixed with a less abundant population of microbial cells ranging from >0.2 to 1.5 μm in length. Fluorescent DNA staining, electron microscopy (EM) observations, elemental analysis, and extraction of high-molecular-weight genomic DNA indicated that a significant portion of these ultrasmall particles are cells. A continuous electron-dense layer surrounding a less electron-dense region was observed by EM, indicating the presence of a biological membrane surrounding a cytoplasm. The ultrasmall cells are 0.192 ± 0.065 μm, with morphology characteristic of coccoid and diplococcic bacterial cells, often surrounded by iron-rich capsular structures. EM observations also detected the presence of smaller unidentified nanoparticles of 0.020 to 0.140 μm among the brine cells. A 16S rRNA gene clone library from the brine 0.1- to 0.2-μm-size fraction revealed a relatively low-diversity assemblage of Bacteria sequences distinct from the previously reported >0.2-μm-cell-size Lake Vida brine assemblage. The brine 0.1- to 0.2-μm-size fraction was dominated by the Proteobacteria-affiliated genera Herbaspirillum, Pseudoalteromonas, and Marinobacter. Cultivation efforts of the 0.1- to 0.2-μm-size fraction led to the isolation of Actinobacteria-affiliated genera Microbacterium and Kocuria. Based on phylogenetic relatedness and microscopic observations, we hypothesize that the ultrasmall cells in Lake Vida brine are ultramicrocells that are likely in a reduced size state as a result of environmental stress or life cycle-related conditions.

  5. Characterization of the volatile profile of Antarctic bacteria by using solid-phase microextraction-gas chromatography-mass spectrometry.

    Science.gov (United States)

    Romoli, Riccardo; Papaleo, Maria Cristiana; de Pascale, Donatella; Tutino, Maria Luisa; Michaud, Luigi; LoGiudice, Angelina; Fani, Renato; Bartolucci, Gianluca

    2011-10-01

    Bacteria belonging to the Burkholderia cepacia complex (Bcc) are significant pathogens in Cystic Fibrosis (CF) patients and are resistant to a plethora of antibiotics. In this context, microorganisms from Antarctica are interesting because they produce antimicrobial compounds inhibiting the growth of other bacteria. This is particularly true for bacteria isolated from Antarctic sponges. The aim of this work was to characterize a set of Antarctic bacteria for their ability to produce new natural drugs that could be exploited in the control of infections in CF patients by Bcc bacteria. Hence, 11 bacterial strains allocated to different genera (e.g., Pseudoalteromonas, Arthrobacter and Psychrobacter) were tested for their ability to inhibit the growth of 21 Bcc strains and some other human pathogens. All these bacteria completely inhibited the growth of most, if not all, Bcc strains, suggesting a highly specific activity toward Bcc strains. Experimental evidences showed that the antimicrobial compounds are small volatile organic compounds, and are constitutively produced via an unknown pathway. The microbial volatile profile was obtained by SPME-GC-MS within the m/z interval of 40-450. Solid phase micro extraction technique affords the possibility to extract the volatile compounds in head space with a minimal sample perturbation. Principal component analysis and successive cluster discriminant analysis was applied to evaluate the relationships among the volatile organic compounds with the aim of classifying the microorganisms by their volatile profile. These data highlight the potentiality of Antarctic bacteria as novel sources of antibacterial substances to face Bcc infections in CF patients. Copyright © 2011 John Wiley & Sons, Ltd.

  6. Anti-biofilm activities from marine cold adapted bacteria against staphylococci and Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    Rosanna ePapa

    2015-12-01

    Full Text Available Microbial biofilms have great negative impacts on the world’s economy and pose serious problems to industry, public health and medicine. The interest in the development of new approaches for the prevention and treatment of bacterial adhesion and biofilm formation has increased. Since, bacterial pathogens living in biofilm induce persistent chronic infections due to the resistance to antibiotics and host immune system. A viable approach should target adhesive properties without affecting bacterial vitality in order to avoid the appearance of resistant mutants. Many bacteria secrete anti-biofilm molecules that function in regulating biofilm architecture or mediating the release of cells from it during the dispersal stage of biofilm life cycle. Cold-adapted marine bacteria represent an untapped reservoir of biodiversity able to synthesize a broad range of bioactive compounds, including anti-biofilm molecules.The anti-biofilm activity of cell-free supernatants derived from sessile and planktonic cultures of cold-adapted bacteria belonging to Pseudoalteromonas, Psychrobacter and Psychromonas species were tested against Staphylococcus aureus, Staphylococcus epidermidis and Pseudomonas aeruginosa strains. Reported results demonstrate that we have selected supernatants, from cold-adapted marine bacteria, containing non-biocidal agents able to destabilize biofilm matrix of all tested pathogens without killing cells. A preliminary physico-chemical characterization of supernatants was also performed, and these analyses highlighted the presence of molecules of different nature that act by inhibiting biofilm formation. Some of them are also able to impair the initial attachment of the bacterial cells to the surface, thus likely containing molecules acting as anti-biofilm surfactant molecules.The described ability of cold-adapted bacteria to produce effective anti-biofilm molecules paves the way to further characterization of the most promising molecules

  7. Spatial and Species Variations in Bacterial Communities Associated with Corals from the Red Sea as Revealed by Pyrosequencing

    KAUST Repository

    Lee, O. O.

    2012-08-03

    Microbial associations with corals are common and are most likely symbiotic, although their diversity and relationships with environmental factors and host species remain unclear. In this study, we adopted a 16S rRNA gene tag-pyrosequencing technique to investigate the bacterial communities associated with three stony Scleractinea and two soft Octocorallia corals from three locations in the Red Sea. Our results revealed highly diverse bacterial communities in the Red Sea corals, with more than 600 ribotypes detected and up to 1,000 species estimated from a single coral species. Altogether, 21 bacterial phyla were recovered from the corals, of which Gammaproteobacteria was the most dominant group, and Chloroflexi, Chlamydiae, and the candidate phylum WS3 were reported in corals for the first time. The associated bacterial communities varied greatly with location, where environmental conditions differed significantly. Corals from disturbed areas appeared to share more similar bacterial communities, but larger variations in community structures were observed between different coral species from pristine waters. Ordination methods identified salinity and depth as the most influential parameters affecting the abundance of Vibrio, Pseudoalteromonas, Serratia, Stenotrophomonas, Pseudomonas, and Achromobacter in the corals. On the other hand, bacteria such as Chloracidobacterium and Endozoicomonas were more sensitive to the coral species, suggesting that the host species type may be influential in the associated bacterial community, as well. The combined influences of the coral host and environmental factors on the associated microbial communities are discussed. This study represents the first comparative study using tag-pyrosequencing technology to investigate the bacterial communities in Red Sea corals.

  8. Macroalgal Morphogenesis Induced by Waterborne Compounds and Bacteria in Coastal Seawater.

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    Jan Grueneberg

    Full Text Available Axenic gametes of the marine green macroalga Ulva mutabilis Føyn (Ria Formosa, locus typicus exhibit abnormal development into slow-growing callus-like colonies with aberrant cell walls. Under laboratory conditions, it was previously demonstrated that all defects in growth and thallus development can be completely abolished when axenic gametes are inoculated with a combination of two specific bacterial strains originally identified as Roseobacter sp. strain MS2 and Cytophaga sp. strain MS6. These bacteria release diffusible morphogenetic compounds (= morphogens, which act similar to cytokinin and auxin. To investigate the ecological relevance of the waterborne bacterial morphogens, seawater samples were collected in the Ria Formosa lagoon (Algarve, Southern Portugal at 20 sampling sites and tidal pools to assess their morphogenetic effects on the axenic gametes of U. mutabilis. Specifically the survey revealed that sterile-filtered seawater samples can completely recover growth and morphogenesis of U. mutabilis under axenic conditions. Morphogenetic activities of free-living and epiphytic bacteria isolated from the locally very abundant Ulva species (i.e., U. rigida were screened using a multiwell-based testing system. The most represented genera isolated from U. rigida were Alteromonas, Pseudoalteromonas and Sulfitobacter followed by Psychrobacter and Polaribacter. Several naturally occurring bacterial species could emulate MS2 activity (= induction of cell divisions regardless of taxonomic affiliation, whereas the MS6 activity (= induction of cell differentiation and cell wall formation was species-specific and is probably a feature of difficult-to-culture bacteria. Interestingly, isolated bacteroidetes such as Algoriphagus sp. and Polaribacter sp. could individually trigger complete Ulva morphogenesis and thus provide a novel mode of action for bacterial-induced algal development. This study also highlights that the accumulation of algal

  9. Macroalgal Morphogenesis Induced by Waterborne Compounds and Bacteria in Coastal Seawater.

    Science.gov (United States)

    Grueneberg, Jan; Engelen, Aschwin H; Costa, Rodrigo; Wichard, Thomas

    2016-01-01

    Axenic gametes of the marine green macroalga Ulva mutabilis Føyn (Ria Formosa, locus typicus) exhibit abnormal development into slow-growing callus-like colonies with aberrant cell walls. Under laboratory conditions, it was previously demonstrated that all defects in growth and thallus development can be completely abolished when axenic gametes are inoculated with a combination of two specific bacterial strains originally identified as Roseobacter sp. strain MS2 and Cytophaga sp. strain MS6. These bacteria release diffusible morphogenetic compounds (= morphogens), which act similar to cytokinin and auxin. To investigate the ecological relevance of the waterborne bacterial morphogens, seawater samples were collected in the Ria Formosa lagoon (Algarve, Southern Portugal) at 20 sampling sites and tidal pools to assess their morphogenetic effects on the axenic gametes of U. mutabilis. Specifically the survey revealed that sterile-filtered seawater samples can completely recover growth and morphogenesis of U. mutabilis under axenic conditions. Morphogenetic activities of free-living and epiphytic bacteria isolated from the locally very abundant Ulva species (i.e., U. rigida) were screened using a multiwell-based testing system. The most represented genera isolated from U. rigida were Alteromonas, Pseudoalteromonas and Sulfitobacter followed by Psychrobacter and Polaribacter. Several naturally occurring bacterial species could emulate MS2 activity (= induction of cell divisions) regardless of taxonomic affiliation, whereas the MS6 activity (= induction of cell differentiation and cell wall formation) was species-specific and is probably a feature of difficult-to-culture bacteria. Interestingly, isolated bacteroidetes such as Algoriphagus sp. and Polaribacter sp. could individually trigger complete Ulva morphogenesis and thus provide a novel mode of action for bacterial-induced algal development. This study also highlights that the accumulation of algal growth factors in

  10. Sample size affects 13C-18O clumping in CO2 derived from phosphoric acid digestion of carbonates

    Science.gov (United States)

    Wacker, U.; Fiebig, J.

    2011-12-01

    In the recent past, clumped isotope analysis of carbonates has become an important tool for terrestrial and marine paleoclimate reconstructions. For this purpose, 47/44 ratios of CO2 derived from phosphoric acid digestion of carbonates are measured. These values are compared to the corresponding stochastic 47/44 distribution ratios computed from determined δ13C and δ18O values, with the deviation being finally expressed as Δ47. For carbonates precipitated in equilibrium with its parental water, the magnitude of Δ47 is a function of temperature only. This technique bases on the fact that the isotopic fractionation associated with phosphoric acid digestion of carbonates is kinetically controlled. In this way, the concentration of 13C-18O bondings in the evolved CO2 remains proportional to the number of corresponding bondings inside the carbonate lattice. A relationship between carbonate growth temperature and Δ47 has recently been determined experimentally by Ghosh et al. (2006)1, who performed the carbonate digestion with 103% H3PO4 at 25°C after precipitating the carbonates inorganically at temperatures ranging from 1-50°C. In order to investigate the kinetic parameters associated with the phosphoric acid digestion reaction at 25°C, we have analyzed several natural carbonates at varying sample sizes. Amongst these are NBS 19, internal Carrara marbel, Arctica islandica and cold seep carbonates. Sample size was varied between 4 and 12mg. All samples exhibit a systematic trend to increasing Δ47 values with decreasing sample size, with absolute variations being restricted to ≤0.10%. Additional tests imply that this effect is related to the phosphoric acid digestion reaction. Most presumably, either the kinetic fractionation factor expressing the differences in 47/44 ratios between evolved CO2 and parental carbonate slightly depends on the concentration of the digested carbonate or traces of water exchange with C-O-bearing species inside the acid, similar to

  11. Sr/Ca and Mg/Ca in Glycymeris glycymeris (Bivalvia) shells from the Iberian upwelling system: Ontogeny and environmental control

    Science.gov (United States)

    Freitas, Pedro; Richardson, Christopher; Chenery, Simon; Monteiro, Carlos; Butler, Paul; Reynolds, David; Scourse, James; Gaspar, Miguel

    2017-04-01

    Bivalve shells have a great potential as high-resolution geochemical proxy archives of marine environmental conditions. In addition, sclerochronology of long-lived bivalve species (e.g. Arctica islandica) provides a timeline of absolutely dated shell material for geochemical analysis that can extend into the past beyond the lifetime of single individuals through the use of replicated crossmatched centennial to millennial chronologies. However, the interpretation of such records remains extremely challenging and complex, with multiple environmental and biological processes affecting element incorporation in the shell (e.g. crystal fabrics, organic matrix, biomineralization mechanisms and physiological processes). As a result, the effective use of bivalve shell elemental/Ca ratios as palaeoenvironmental proxies has been limited, often to species-specific applications or applications restricted to particular environmental settings. The dog-cockle, Glycymeris glycymeris, is a relatively long-lived bivalve (up to 200 years) that occurs in coarse-grained subtidal sediments of coastal shelf seas of Europe and North West Africa. Glycymeris glycymeris shells provide a valuable, albeit not fully explored, archive to reconstruct past environmental variability in an area lacking sclerochronological studies due to the rarity of long-lived bivalves and lack of coral reefs. In this study, we evaluate the potential of Sr/Ca and Mg/Ca ratios in G. glycymeris shells as geochemical proxies of upwelling conditions in the Iberian Upwelling System, the northern section of the Canary Current Eastern Boundary Upwelling System. Sr/Ca and Mg/Ca generally co-varied significantly and a clear ontogenetic, non-environmental related change in Sr/Ca and Ba/Ca variability was observed. High Sr/Ca and Mg/Ca ratios in older shells (> 10 years old) were found to be associated with the occurrence of growth lines deposited during the winter reduction in shell growth. Nevertheless, Sr/Ca and Mg

  12. Climatic variability in sclerochronological records from the northern North Sea

    Science.gov (United States)

    Trofimova, T.; Andersson Dahl, C.; Bonitz, F. G. W.

    2016-12-01

    Highly resolved palaeoreconstructions that can extend instrumental records back through time is a fundament for our understanding of a climate of the last millennia. Only a few established extratropical marine paleo archives enable the reconstruction of key ocean processes at annual to sub-annual time scales. Bivalves have been shown to provide a useful archive with high temporal resolution. The species Arctica islandica is unique proxy due to its exceptional longevity combined with sensitivity to changes in environmental conditions. In this study, we investigate the impact of climate variability on sclerochronological records of A. islandica from the Viking Bank in the northern North Sea. The hydrographical characteristics of this location are mainly controlled by the major inflow of Atlantic water in the North Sea and can potentially be reflected in the shell composition and growth of A. islandica. To reconstruct environment conditions, we use shells of living and subfossil specimens of A. islandica collected by dredging at depths around 100 meters. The annual growth bands within the shells were determined and growth increments widths were measured. By cross-matching 30 individual increment-width time series, we built an absolutely dated 265-year long shell-growth chronology spanning the time interval 1748-2013 AD. The relatively high Rbar (>0.5) and EPS (>0.85) values indicate a common environmental forcing on the shell growth within the population. The growth chronology preserves a 20-30 yr variability prior to 1900 which fades out towards the present. That change suggests a possible regime shift at the beginning of a 20th century. Ongoing work mainly focuses on comparing the shell-growth chronology with existing observational time series of climatic parameters to determine controlling factors and test the use of growth chronologies for climate reconstruction in this area. For reconstructing seasonality, we analyse the stable oxygen isotope composition of the

  13. "Recent" macrofossil remains from the Lomonosov Ridge, central Arctic Ocean

    Science.gov (United States)

    Le Duc, Cynthia; de Vernal, Anne; Archambault, Philippe; Brice, Camille; Roberge, Philippe

    2016-04-01

    The examination of surface sediment samples collected from 17 sites along the Lomonosov Ridge at water depths ranging from 737 to 3339 meters during Polarstern Expedition PS87 in 2014 (Stein, 2015), indicates a rich biogenic content almost exclusively dominated by calcareous remains. Amongst biogenic remains, microfossils (planktic and benthic foraminifers, pteropods, ostracods, etc.) dominate but millimetric to centrimetric macrofossils occurred frequently at the surface of the sediment. The macrofossil remains consist of a large variety of taxa, including gastropods, bivalvia, polychaete tubes, scaphopods, echinoderm plates and spines, and fish otoliths. Among the Bivalvia, the most abundant taxa are Portlandia arctica, Hyalopecten frigidus, Cuspidaria glacilis, Policordia densicostata, Bathyarca spp., and Yoldiella spp. Whereas a few specimens are well preserved and apparently pristine, most mollusk shells displayed extensive alteration features. Moreover, most shells were covered by millimeter scale tubes of the serpulid polychaete Spirorbis sp. suggesting transport from low intertidal or subtidal zone. Both the ecological affinity and known geographic distribution of identified bivalvia as named above support the hypothesis of transportation rather than local development. In addition to mollusk shells, more than a hundred fish otoliths were recovered in surface sediments. The otoliths mostly belong to the Gadidae family. Most of them are well preserved and without serpulid tubes attached to their surface, suggesting a local/regional origin, unlike the shell remains. Although recovered at the surface, the macrofaunal assemblages of the Lomonosov Ridge do not necessarily represent the "modern" environments as they may result from reworking and because their occurrence at the surface of the sediment may also be due to winnowing of finer particles. Although the shells were not dated, we suspect that their actual ages may range from modern to several thousands of

  14. Molluscan sclerochronology on the Faroese Shelf and its potential to obtain closer insights into the climate variability of North Atlantic water masses

    Science.gov (United States)

    Bonitz, F. G. W.; Andersson Dahl, C.; Trofimova, T.

    2016-12-01

    In this study, we investigate the climate variability in the North Atlantic during the last 350 years by applying sclerochronological methods. The inflow of North Atlantic water masses into the Arctic and the Norwegian Sea is important for the climate in these regions. A better understanding of the climate variability on highly resolved time scales is needed to obtain a better fundament for climate predictions for these areas. However, highly resolved paleoclimate records are sparse in the North Atlantic and instrumental data cover only the last 50 - 150 years. Bivalve shells provide highly resolved climate archives, especially the shells of the long-lived bivalve species Arctica islandica. This widely occurring species forms annual growth increments, which can be analyzed similarly to tree rings. Climatic and oceanographic changes are recorded population-wide in the shell`s growth rate and in the isotopic composition of the shell. Hence, multi-centennial absolutely dated chronologies can be built by cross-matching live-collected and sub-fossil specimens. Our chronology building effort has led to the first multi-centennial absolutely dated chronology from the Faroese Shelf covering the time period from AD 1642 - 2013. The growth indices of the chronology anti-correlate with April - September sea surface temperatures (SST) for the last 100 years indicating favorable conditions for growth when temperatures are lower. This also suggests that the main growing season of A. islandica around the Faroe Islands occurs in this time period; a hypothesis supported by δ18O-based temperature reconstructions from growth increments representing the years 2001 - 2013. The RBAR, which is an indicator for the signal strength throughout the chronology shows an inverse relationship with Atlantic Multi-decadal Oscillation (AMO) data indicating that periods of higher AMO indexes result in a weakened signal strength in the chronology for the same time period. In conclusion, our results

  15. Interacting effects of elevated temperature and additional water on plant physiology and net ecosystem carbon fluxes in a high Arctic ecosystem

    Science.gov (United States)

    Maseyk, Kadmiel; Seibt, Ulrike; Lett, Céline; Lupascu, Massimo; Czimczik, Claudia; Sullivan, Patrick; Welker, Jeff

    2013-04-01

    Arctic ecosystems are experiencing temperature increases more strongly than the global average, and increases in precipitation are also expected amongst the climate impacts on this region in the future. These changes are expected to strongly influence plant physiology and soil biogeochemistry with subsequent implications for system carbon balance. We have investigated the effects of a long-term (10 years) increase in temperature, soil water and the combination of both on a tundra ecosystem at a field manipulation experiment in NW Greenland. Leaf gas exchange, chlorophyll fluorescence, carbon (C) and nitrogen (N) content and leaf isotopic composition, and leaf morphology were measured on Salix arctica plants in treatment and control plots in June-July 2011, and continuous measurements of net plant and soil fluxes of CO2 and water were made using automatic chambers coupled to a trace gas laser analyzer. Plants in the elevated temperature (T2) treatment had the highest photosynthetic capacity in terms of net CO2 assimilation rates and photosystem II efficiencies, and lowest rates of non-photochemical energy dissipation during photosynthesis. T2 plants also had the highest leaf N content, specific leaf area (SLA) and saturation light level of photosynthesis. It appears that warming increases soil N availability, which the plants direct towards increasing photosynthetic capacity and producing larger thinner leaves. On the other hand, the plants in the plots with both elevated temperatures and additional water (T2W) had the lowest photosystem II efficiencies and the highest rates of non-photochemical energy dissipation, due more to higher levels of constitutive energy dissipation than regulated thermal quenching. Watering, both in combination with higher temperatures and alone (W treatment), also reduced leaf SLA and leaf N relative to control plots. However, net photosynthetic rates remained similar to control plants, due in part to higher stomatal conductance (W) and

  16. Evolution of Hydrocarbon-Degrading Microbial Communities in the Aftermath of the Deepwater Horizon Oil Well Blowout in the Gulf of Mexico

    Science.gov (United States)

    Andersen, G.; Dubinsky, E. A.; Chakraborty, R.; Hollibaugh, J. T.; Hazen, T. C.

    2012-12-01

    The Deepwater Horizon oil spill created large plumes of dispersed oil and gas that remained deep in the water column and stimulated growth of several deep-sea bacteria that can degrade hydrocarbons at cold temperatures. We tracked microbial community composition before, during and after the 83-day spill to determine relationships between microbial dynamics, and hydrocarbon and dissolved-oxygen concentrations. Dominant bacteria in plumes shifted drastically over time and were dependent on the concentration of hydrocarbons, and the relative quantities of insoluble and soluble oil fractions. Unmitigated flow from the wellhead early in the spill resulted in the highest concentrations of oil and relatively more n-alkanes suspended in the plume as small oil droplets. These conditions resulted in near complete dominance by alkane-degrading Oceanospirillales, Pseudomonas and Shewanella. Six-weeks into the spill overall hydrocarbon concentrations in the plume decreased and were almost entirely composed of BTEX after management actions reduced emissions into the water column. These conditions corresponded with the emergence of Colwellia, Pseudoalteromonas, Cycloclasticus and Halomonas that are capable of degrading aromatic compounds. After the well was contained dominant plume bacteria disappeared within two weeks after the spill and transitioned to an entirely different set of bacteria dominated by Flavobacteria, Methylophaga, Alteromonas and Rhodobacteraceae that were found in anomalous oxygen depressions throughout August and are prominent degraders of both high molecular weight organic matter as well as hydrocarbons. Bio-Sep beads amended with volatile hydrocarbons from MC-252 oil were used from August through September to create hydrocarbon-amended traps for attracting oil-degrading microbes in situ. Traps were placed at multiple depths on a drilling rig about 600-m from the original MC-252 oil spill site. Microbes were isolated on media using MC-252 oil as the sole

  17. Effectiveness of seawater reverse osmosis (SWRO) pretreatment systems in removing transparent exopolymer particles (TEP) substances

    KAUST Repository

    Lee, Shang-Tse

    2015-05-01

    Transparent exopolymer particles (TEP) have been reported as one of the main factors of membrane fouling in seawater reverse osmosis (SWRO) process. Research has been focused on algal TEP so far, overlooking bacterial TEP. This thesis investigated the effects of coagulation on removal of bacterial TEP/TEP precursors in seawater and subsequent reduction on TEP fouling in ultrafiltration (UF), as a pretreatment of SWRO. Furthermore, the performance of pretreatment (coagulation + UF) has been investigated on a bench-scale SWRO system. TEP/TEP precursors were harvested from a strain of marine bacteria, Pseudoalteromonas atlantica, isolated from the Red Sea. Isolated bacterial organic matter (BOM), containing 1.5 mg xanthan gum eq./L TEP/TEP precursors, were dosed in Red Sea water to mimic a high TEP concentration event. Bacterial TEP/TEP precursors added to seawater were coagulated with ferric chloride and aluminum sulfate at different dosages and pH. Results showed that ferric chloride had a better removal efficiency on TEP/TEP precursors. Afterwards, the non-coagulated/coagulated seawater were tested on a UF system at a constant flux of 130 L/m2h, using two types of commercially available membranes, with pore sizes of 50 kDa and 100 kDa, respectively. The fouling potential of coagulated water was determined by the Modified Fouling Index (MFI-UF). Transmembrane pressure (TMP) was also continuously monitored to investigate the fouling development on UF membranes. TEP concentrations in samples were determined by the alcian blue staining assay. Liquid chromatography-organic carbon detection (LC-OCD) was used to determine the removal of TEP precursors with particular emphasis on biopolymers. Finally, SWRO tests showed that TEP/TEP precursors had a high fouling potential as indicated by MFI-UF, corresponding to the TMP measurements. Coagulation could substantially reduce TEP/TEP precursors fouling in UF when its dosage was equal or higher than 0.2 mg Fe/L. The flux decline

  18. Antioxidant activity of Sphaerococcus coronopifolius associated bacteria

    Directory of Open Access Journals (Sweden)

    Nádia Fino

    2014-06-01

    Full Text Available Associated bacteria living on macroalgae surfaces are an interesting source of new secondary metabolites with biological activities. The aim of this study was the isolation and identification of epiphytic bacteria from the marine algae Sphaerococcus coronopifolius and the evaluation of the antioxidant activity of the bacteria extracts. The identification of epiphytic bacteria was determined by 16S rRNA gene sequencing. Bacteria extracts were obtained with methanol and dichloromethane (1:1 extraction. Antioxidant activity was evaluated by quantification of total phenolic content (TPC, 2,2-diphenyl-1-picrylhydrazyl (DPPH radical scavenging activity and oxygen radical absorbent capacity (ORAC. The extracts with higher antioxidant activity were tested on MCF-7 and HepG-2 cell lines in oxidative stress conditions induced by H2O2 at 0.2 mM and 0.5 mM, respectively. In total were isolated 21 Sphaerococcus coronopifolius associated bacteria and identified as Vibrio sp. (28.57%, Shewanella sp. (23.81%, Pseudoalteromonas sp. (19.05%, Bacillus sp. (9.52% and Halomonas sp. (9.52%. Two (9.52% of them presented less than 90% Basic Local Alignment Search Tool (BLAST match. The epiphytic bacteria with the most antioxidant potential evaluated by ORAC and DPPH methods were Sp2, Sp12, Sp23, Sp25 and Sp27. The strain Sp4 show high antioxidant activity in all antioxidant methods (ORAC, DPPH and TPC. In oxidative stress conditions on MCF-7 cell line, the extracts of bacteria (1mg.ml-1: 24hours Sp4 (16.15%, Sp25 (17.95% and Sp27 (10.65% prevented the cell death induced by H2O2. In the HepG-2 cell line was the extracts of Sp2 (9.01%, Sp4 (11.21%, Sp12 (7.20% and Sp23 (8.81% bacteria that high prevented the oxidative stress condition induced by H2O2. In conclusion, the Sphaerococcus coronopifolius associated bacteria can be an interesting and excellent source of marine natural compounds with antioxidant activity.

  19. IDENTIFICACIÓN MOLECULAR DE POBLACIONES BACTERIANAS ASOCIADAS AL CARACOL PALA (Strombus gigas DEL CARIBE COLOMBIANO

    Directory of Open Access Journals (Sweden)

    EDINSON ANDRÉS ACOSTA

    2009-01-01

    Full Text Available El caracol Pala, Strombus gigas (Strombidae, es de gran importancia ecológica y so- cioeconómica en el área caribeña colombiana. Sin embargo, es una especie catalogada como "vulnerable" y existe muy poca información referente a las especies bacterianas asociadas al caracol que puedan ser importantes para el desarrollo, manejo productivo y de seguridad acuícola de estos gastrópodos. En este trabajo, nosotros empleamos un estudio microbiológico y molecular de la región intergénica entre los genes 16S y 23S rDNA, análisis del gen rDNA 16S y secuenciación, para analizar las bacterias asociadas al caracol Pala (S. gigas. La composición de bacterias cultivables asociadas fue evaluada por su capacidad para crecer en agar marino y en medios de cultivos selectivos. De un total de 28 muestras analizadas encontramos que el número de bacterias cultivadas en condiciones aerobias fue de alrededor 106 ufc mL-1 donde las bacterias pertenecientes a la familia Vibrionacea fueron las más abundantes, cerca de >105 ufc mL-1 . El análisis molecular de la región intergénica entre los genes 16S y 23S rDNA de las diferentes muestras, reveló una gran complejidad bacteriana asociada a S. gigas. Las secuencias de los amplificados del gen rDNA 16S identificó Pseudoalteromonas sp., Halomonas sp., Psycrobacter sp., Cobetia sp., Pseudomonas sp. y Vibrios sp. Nuestros resultados podrían sugerir un rol importante de estas bacterias como componentes de la comunidad asociada al S. gigas. Esta información puede complementar los estudios que se están implementando en los procesos para la conservación y repoblamiento de las poblaciones de S. gigas en Colombia.

  20. Coupling of fog and marine microbial content in the near-shore coastal environment

    Directory of Open Access Journals (Sweden)

    M. E. Dueker

    2012-02-01

    Full Text Available Microbes in the atmosphere (microbial aerosols play an important role in climate and provide an ecological and biogeochemical connection between oceanic, atmospheric, and terrestrial environments. However, the sources and environmental factors controlling the concentration, diversity, transport, and viability of microbial aerosols are poorly understood. This study examined culturable microbial aerosols from a coastal environment in Maine (USA and determined the effect of onshore wind speed and fog presence on deposition rate, source, and community composition. During fog events with low onshore winds (<2 m s−1 the near-shore deposition of microbial aerosols (microbial fallout decreased with increasing wind speeds, whereas microbial fallout rates under clear conditions and comparable low wind speeds showed no wind speed dependence. Mean aerosol particle size also increased with onshore wind speed when fog was present, indicating increased shoreward transport of larger aerosol particles. 16S rRNA sequencing of culturable ocean surface bacteria and microbial aerosols deposited onshore resulted in the detection of 31 bacterial genera, with 5 dominant genera (Vibrio, Bacillus, Pseudoalteromonas, Psychrobacter, Salinibacterium making up 66 % of all sequences. The sequence library from microbial aerosol isolates, as with libraries found in other coastal/marine aerosol studies, was dominated at the phylum level by Proteobacteria, with additional representation from Firmicutes, Actinobacteria and Bacteroidetes. Seventy-five percent of the culturable microbial aerosols falling out under foggy conditions were most similar to GenBank-published sequences detected in marine environments. Using a 97 % similarity cut-off, sequence libraries from ocean surface and fog isolates shared eight operational taxonomic units (OTU's in total, three of which were the most dominant OTU's in the library, representing large fractions of the ocean (28

  1. POPULATION PHARMACOKINETICS OF ENROFLOXACIN AND ITS METABOLITE CIPROFLOXACIN IN THE GREEN SEA URCHIN (STRONGYLOCENTROTUS DROEBACHIENSIS) FOLLOWING INTRACOELOMIC AND IMMERSION ADMINISTRATION.

    Science.gov (United States)

    Phillips, Brianne E; Harms, Craig A; Lewbart, Gregory A; Lahner, Lesanna L; Haulena, Martin; Rosenberg, Justin F; Papich, Mark G

    2016-03-01

    Sea urchin mass mortality events have been attributed to both infectious and noninfectious etiologies. Bacteria, including Vibrio spp. and Pseudoalteromonas spp., have been isolated during specific mortality events. Aquarium collection sea urchins are also subject to bacterial infections and could benefit from antimicrobial treatment, but pharmacokinetic studies have been lacking for this invertebrate group until recently. This study evaluated the pharmacokinetics of enrofloxacin and its active metabolite ciprofloxacin in the green sea urchin (Strongylocentrotus droebachiensis) after intracoelomic injection and medicated bath immersion administration. The utility of a population pharmacokinetic method using nonlinear mixed effects modeling (NLME) was also evaluated. Thirty sea urchins were assigned to either the injection or immersion group. Twelve study animals and three untreated controls were utilized for each administration method: enrofloxacin 10 mg/kg intracoelomic injection or a 6-hr enrofloxacin 10 mg/L immersion. Each animal was sampled four times from 0 to 120 hr. Water samples were collected during immersion treatment and posttreatment time points in both groups. Hemolymph and water sample drug concentrations were analyzed using high-performance liquid chromatography, and pharmacokinetic parameters were determined using an NLME population pharmacokinetic method. Enrofloxacin concentrations were fit to a two-compartment model with first-order input for the intracoelomic injection group. The enrofloxacin elimination half-life (t½), peak hemolymph concentration (CMAX), and area under the curve (AUC) were 38.82 hr, 90.92 μg/ml, and 1,199 hr·μg/ml, respectively. Enrofloxacin was modeled to a one-compartment model with first-order input for the immersion treatment. The enrofloxacin t½, CMAX, and AUC were 33.46 hr, 0.48 μg/ml, and 32.88 hr·μg/ml, respectively. Ciprofloxacin was detected in trace concentrations in all hemolymph samples, indicating

  2. Cell–cell and cell–surface interactions in an illuminated biofilm: Implications for marine sediment stabilization†

    Directory of Open Access Journals (Sweden)

    Cooksey Keith E

    2001-10-01

    Full Text Available Most wetted surfaces that are illuminated support a population of phototrophs. The marine sediment is no exception and there the major component of the microphytobenthic population is diatoms. These organisms are credited with stabilizing the sediment against physical disturbance by virtue of the extracellular carbohydrate polymers that they elaborate. However, diatoms synthesize and secrete several carbohydrate polymers and it is not certain which of them is involved in the stabilization process. In order to investigate this, we have constructed small glass bead-filled flow through bioreactors to mimic marine sediments. The flow rate through the bioreactors was found to reflect the physical stability of the bead bed. Thus flow rate was measured as a function of diatom growth and the production of three operationally-defined polymers, i.e., those soluble in the medium, those soluble in 0.5 M NaHCO3 at 90 °C and those not soluble in either solvent (matrix polymer. Growth of the diatoms did not change the hydraulic conductivity of the bioreactors. For Amphora coffeaeformis, neither did the production of medium-soluble nor NaHCO3-soluble polymers. However, matrix polymer accumulation was directly correlated with a reduction in flow (regression coefficient R2 = 0.96 and stabilization against physical disturbance. Results with species of Navicula were not as clear. Both NaHCO3-soluble and matrix polymers were involved in producing the flow reduction. In the same manner we also measured the effect of Pseudoalteromonas haloplanktis growth on bead bed hydraulic conductivity and bead bed stability. Growing alone, no effect was found, but in co-culture with a single diatom species, the bacteria reduced the diatom effect on flow through the bioreactors seen earlier, however did not reduce the extent of their growth. Confocal scanning laser microscopy of beads colonized with diatoms alone, or diatoms in co-culture with bacteria, revealed that P

  3. North-Western Palaearctic species of Pristiphora (Hymenoptera, Tenthredinidae

    Directory of Open Access Journals (Sweden)

    Marko Prous

    2017-09-01

    arctica Lindqvist, 1959, syn. n., Pachynematus incisus Lindqvist, 1970, syn. n., Pachynematus intermedius Verzhutskii, 1974, syn. n., and P. mongololaricis Haris, 2003, syn. n. with P. malaisei (Lindqvist, 1952; Nematus anderschi Zaddach, 1876, syn. n., P. inocreata Konow, 1902, syn. n., and P. discolor Lindqvist, 1975, syn. n. with P. nigricans (Eversmann, 1847; Lygaeonematus tenuicornis Lindqvist, 1955, syn. n. with P. paralella (Hartig, 1840; Lygaeonematus concolor Lindqvist, 1952, syn. n. with P. pseudocoactula (Lindqvist, 1952; P. flavipicta Lindqvist, 1975, syn. n., P. flavopleura Haris, 2002, syn. n., P. mongoloexigua Haris, 2002, syn. n., and P. mongolofausta Haris, 2003, syn. n. with P. punctifrons (Thomson, 1871; P. listoni Lacourt, 1998, syn. n. with P. sootryeni Lindqvist, 1955; P. gaunitzi Lindqvist, 1968, syn. n. with P. testacea (Jurine, 1807; and Nematus breviusculus Eversmann, 1847, syn. n. with Euura melanocephalus (Hartig, 1837. The valid name of Pachynematus (Pikonema carpathiensis Haris, 2001 is Nematinus carpathiensis (Haris, 2001 comb. n. Lectotypes are designated for 43 taxa. An illustrated electronic key made with Lucid and a traditional dichotomous key are provided to facilitate identification of the species. Species belonging to the carinata (previously Lygaeotus, micronematica (previously Lygaeophora, and rufipes (also known as thalictri or aquilegiae groups are not keyed to the species level, because additional research is needed to delimit the species more reliably in these groups. Phylogeny of Pristiphora is reconstructed based on one mitochondrial (COI and two nuclear (NaK and TPI genes. Remarkably, around 50–60% (depending on the exclusion or inclusion of the carinata, micronematica, and rufipes groups of the species cannot be reliably identified based on COI barcodes. Limited data from nuclear genes indicate a better identification potential (about 20% remain problematic.

  4. Plant eco-physiological responses to multiple environmental and climate changes

    Energy Technology Data Exchange (ETDEWEB)

    Rost Albert, K.

    2009-03-15

    The current global changes of temperature, precipitation, atmospheric CO{sub 2} and UV-B radiation impact in concert ecosystems and processes in an unpredictable way. Therefore multifactor experimentation is needed to unravel the variability in strength of these drivers, whether the factors act additively or synergistically and to establish cause-effect relations between ecosystem processes. This thesis deals with heath plant responses to global change factors (the CLIMAITE project). In a Danish temperate heath ecosystem elevated CO{sub 2}, experimental summer drought, and passive nighttime warming was applied in all combinations (based on the scenario for Denmark anno 2075) and the responses after one year of treatment were investigated through a growing season in Hairgrass (Deschampsia flexousa) and Heather (Calluna vulgaris). In a high arctic heath ecosystem situated in NE-Greenland UV-B exclusion experiments were conducted on Salix arctica and Vaccinium uliginosum during six years. Responses of photosynthesis performance were characterized on the leaf scale by means of leaf gas-exchange (A/Ci curves), chlorophyll-a fluorescence, leaf nitrogen, carbon and delta13C and secondary compounds. The main findings were 1) The different growth strategies of the evergreen Calluna versus the opportunistic bi-phasic Deschampsia affects the photosynthesis response to drought and autumn warming; 2) Elevated CO{sub 2} and warming synergistically increase photosynthesis in spring and autumn; 3) Summer drought decreased photosynthesis in both species, but where Calluna maintained photosynthetic metabolism then major proportion of grass leaves wilted down; 4) Elevated CO{sub 2} did not decrease stomatal conductance, but the treatments affected soil water content positively, pointing to the complex water relations when plants of contrasting growth strategy co-occur; 5) Water availability affected the magnitude of photosynthesis to a higher degree than warming and elevated CO{sub 2

  5. Younger Dryas and Holocene oceanography of the western Labrador Sea region based on foraminifera and sediment proxies from Placentia Bay, Newfoundland

    Science.gov (United States)

    Sheldon, Christina; Pearce, Christof; Seidenkrantz, Marit-Solveig; Kuijpers, Antoon; Reynisson, Njáll F.; Zilmer Christensen, Eva; Juncker Hansen, Mette

    2014-05-01

    Globobulimina auriculata arctica suggests reduced bottom-water stratification. This may have been caused by an increased freshwater release from the Canadian Arctic, linked to the well-known 8.2-kyr event. Around 7.3 kyr BP, the inflow of warmer subsurface waters decreased, when subsurface waters of Placentia Bay returned to relatively cold, subarctic conditions. An enhanced influx of lower-saline water is inferred both by the presence of Elphidium bartletti, indicating an increased flux of meltwater from the Arctic entering Placentia Bay. This fresher water was likely transported by the Labrador Current and strong northerly winds. This scenario was again interrupted around ca 4.4 kyr BP, when higher C. neoteretis again suggest increase influx of Gulf Stream water, a tendency that continued until today, although with possibly slightly better mixing of LC and GS water after ~2.7 kyr BP. This decrease in the strength of the LC, may be linked to a decreased southward flow of LC water due to decreased meltwater release from the Canadian Arctic or due to a shift to a generally more negative Northern Annular Mode.

  6. Ozone hole and its causes; Das Ozonloch und seine Ursachen

    Energy Technology Data Exchange (ETDEWEB)

    Dameris, M. [DLR Deutsches Zentrum fuer Luft- und Raumfahrt e.V., Berlin (Germany); Peter, T. [ETH Zuerich (Switzerland). Inst. fuer Atmosphaere und Klima; Schmidt, U. [Frankfurt Univ. (Germany). Physik der Atmosphaere; Zellner, R. [Duisburg-Essen Univ., Essen (Germany). Inst. fuer Physikalische und Theoretische Chemie

    2007-06-15

    Ozone in the atmosphere is one of the longest and most comprehensively observed trace gases. The pattern of its distribution in global atmospheric space is well understood, although its importance with respect to chemistry and climatology differs significantly in different altitude regions. Whilst ozone in the lower troposphere is mainly important as a source of photooxidants (such as the OH radical) and contributes to global warming via its greenhouse effect, the role of stratospheric ozone is mainly as a protective shield of the terrestrial biosphere against the short wavelength radiation of the sun. In both regions ozone has different mechanisms of formation and destruction. Ozone in the stratosphere is formed via the photochemistry of oxygen. As a result a certain concentration of ozone is establish in an oxygen-only atmosphere. However, the appearance of anthropogenic trace gases such as N{sub 2}O and CFCs have reduced this concentration since they have accelerated the processes of ozone destruction. The reduction of the stratospheric ozone concentration has seen its largest extent over the polar regions in winter/spring. Next to a number of gas phase reactions these reductions have been identified to be caused by surface reactions occurring on polar stratospheric clouds (PSCs). As a consequence the annual extents of destruction are also dependent on the microphysical conditions (temperature, rate of particle formation) of the polar stratosphere in winter. These are in average much more favourable for destruction in the south over Antarctica compared to the north over Arctica. As a result of the Montreal Protocol for the protection of the ozone layer and the associated cease of the production of CFCs and other halogenated compounds the ozone hole is expected to close in some decades to come. The interesting question, however, is how the expected recovery of the ozone layer might be modified or even delayed by climate change, which has an opposite sign - namely

  7. Evidence for smaller extents of the northwestern Greenland Ice Sheet and North Ice Cap during the Holocene

    Science.gov (United States)

    Kelly, M. A.; Osterberg, E. C.; Axford, Y.; Bigl, M.; Birkel, S. D.; Corbett, L. B.; Roy, E. P.; Thompson, J. T.; Whitecloud, S.

    2013-12-01

    The Greenland Ice Sheet (GrIS) and local glaciers on Greenland are responding dynamically to warming temperatures with widespread retreat. GRACE satellite data (e.g., Kahn et al., 2010) and the Petermann Glacier calving events document the recent expansion of ice loss into northwestern Greenland. To improve the ability to estimate future ice loss in a warming climate, we are developing records of the response of the northwestern Greenlandic cryosphere to Holocene climatic conditions, with a focus on past warm periods. Our ongoing research includes analyses of glacial geology, sub-fossil vegetation, lake sediment cores, chironomid assemblages and ice cores combined with glaciological modeling. To constrain past ice extents that were as small as, or smaller than, at present, we recovered sub-fossil vegetation exposed at the receding margins of the GrIS and North Ice Cap (NIC) in the Nunatarssuaq region (~76.7°N, 67.4°W) and of the GrIS near Thule (~76.5°N, 68.7°W). We present vegetation types and radiocarbon ages of 30 plant samples collected in August 2012. In the Nunatarssuaq region, five ages of in situ (rooted) vegetation including Polytrichum moss, Saxifraga nathorstii and grasses located Saxifraga oppositafolia and grasses from ~1-5 m inboard of the NIC margin (excavated from beneath ice) range from ~50 to 310 cal yr BP. The growth of these plants occurred when the GrIS and NIC were at least as small as at present and their ages suggest that ice advances occurred in the last 50-120 yrs. In addition to the in situ samples, we collected plants from well-preserved ground material exposed along shear planes in the GrIS margins. In Nunatarssuaq, two Polytrichum mosses rooted in ground material and exposed along a shear plane in the GrIS margin date to 4680 and 4730 cal yr BP. Near Thule, three ages of Salix arctica rooted in ground material and exposed along a shear plane in the GrIS are ~170-390 cal yr BP. Four ages of plant fragments within ice in a shear

  8. Experimental growth pattern calibration of Antarctic bivalves shells to provide a biogenic archive of long-term high-resolution records of environmental and climatic change.

    Science.gov (United States)

    Lartaud, F.; Toulot, A.; Paulet, Y. M.

    2009-04-01

    Mollusc shells are used as an archive of climate variability in polar areas. The geochemistry (isotope and trace element) of the mineralized tissues is sensitive to the seawater physico-chemical changes (temperature, salinity, primary production …) and the accretionary growth of the shells provide intra-annual to centennial information. However, a serious age and growth profile calibration is necessary to establish a chronological time scale in the micro-sampling strategy. This kind of investigation on biogenic carbonates from Polar Regions suffers to the difficulties of a precise field-based standardization and validation. That's why ecology and shell growth history of many molluscs from those areas still remain unknown. In Boreal seas, bivalve metabolic activity is usually more reduced than in tropical or temperate domains, and the life span increase. For example, growth bands counting in the shells of the ocean Quahog (Arctica islandica) reveals that some of these shells are up to 250 years old (Wanamaker et al., 2008). Nevertheless in those environments, few species have highly defined growth increments calibration. The shell growth of the Antarctic scallop Adamussium colbecki is presently not well defined. Some authors attribute a growth rate close to the temperate equivalent species (Heilmayer et al., 2003) whereas others show a lower performance (Berkman et al., 2004). During the MACARBI program, to investigate the shell growth rate and determine a sclerochronologic profile, Adamussium colbecki and Laternula elliptica shells from Terre Adélie (Antarctic) were marked in situ with calcein during 6 hours and recapture a month later, in the austral summer 2007-2008. At the same time, a control of environmental conditions (temperature, salinity and chlorophyll) was carried out. All shells marked provide a distinct green fluorescent line, corresponding to the date of the marking. Calcein marking did not affect survivorship or growth of A. colbecki and L

  9. Experiments on the survival of six brackish macro-invertebrates from the Baltic Sea after dredged spoil coverage and its implications for the field

    Science.gov (United States)

    Powilleit, M.; Graf, G.; Kleine, J.; Riethmüller, R.; Stockmann, K.; Wetzel, M. A.; Koop, J. H. E.

    2009-02-01

    Physical disturbance by disposal of dredged materials in estuarine and coastal waters may result in burial of benthic fauna. Survival rates depend on a variety of factors including the type and amount of disposed materials and the lifestyle of the organisms. Laboratory burial experiments using six common macrobenthic invertebrates from a brackish habitat of the western Baltic Sea were performed to test the organisms' escape reaction to dredged material disposal. Experimental lab-results were then extrapolated to a field situation with corresponding bottom topography and covering layer thicknesses at experimental field disposal study sites. Resulted survival rates were then verified by comparison with results of an earlier field study at the same disposal sites. Our experimental design in the lab included the disposal of two types of dredged material (i.e. 'till' and 'sand/till mixture') and two covering layer depths (i.e. 10-20 cm and 14-40 cm). All three bivalves Arctica islandica (Linnaeus), Macoma balthica (Linnaeus), Mya arenaria (Linnaeus) and the polychaete Nephtys hombergii (Savigny) successfully burrowed to the surface of a 32-41 cm deposited sediment layer of till or sand/till mixture and restored contact with the overlying water. These high escape potentials could partly be explained by the heterogeneous texture of the till and sand/till mixture with 'voids'. The polychaete Bylgides ( Harmothoe) sarsi (Malmgren) successfully burrowed through a 16 cm covering layer whereas the polychaete Lagis koreni (Malmgren) showed almost no escaping reaction. No general differences in escape behaviour after burial were detected between our test species from the brackish habitat and those reported in the literature for the same species in marine environments. However, a size-dependence in mobility of motile polychaetes and M. arenaria was apparent within our study. In comparison to a thick coverage, thin covering layers (i.e. 15-16 cm and 20 cm) increased the chance of

  10. ER-2 #809 on the SAGE III Ozone Loss and Validation Experiment (SOLVE) with pilot Dee Porter prepari

    Science.gov (United States)

    2000-01-01

    Lockheed Martin pilot Dee Porter climbs up the ladder wearing a heavy tan pressure suit, preparing to board NASA ER-2 #809 at Kiruna, Sweden, for the third flight in the SAGE III Ozone Loss and Validation Experiment. Assisting him is Jim Sokolik, a Lockheed Martin life support technician. Number 809, one of Dryden's two high-flying ER-2 Airborne Science aircraft, a civilian variant of Lockheed's U-2, and another NASA flying laboratory, Dryden's DC-8, were based north of the Arctic Circle in Kiruna, Sweden during the winter of 2000 to study ozone depletion as part of the SAGE III Ozone Loss and Validation Experiment (SOLVE). A large hangar built especially for research, 'Arena Arctica' housed the instrumented aircraft and the scientists. Scientists have observed unusually low levels of ozone over the Arctic during recent winters, raising concerns that ozone depletion there could become more widespread as in the Antarctic ozone hole. The NASA-sponsored international mission took place between November 1999 and March 2000 and was divided into three phases. The DC-8 was involved in all three phases returning to Dryden between each phase. The ER-2 flew sample collection flights between January and March, remaining in Sweden from Jan. 9 through March 16. 'The collaborative campaign will provide an immense new body of information about the Arctic stratosphere,' said program scientist Dr. Michael Kurylo, NASA Headquarters. 'Our understanding of the Earth's ozone will be greatly enhanced by this research.' ER-2s bearing tail numbers 806 and 809 are used as airborne science platforms by NASA's Dryden Flight Research Center. The aircraft are platforms for a variety of high-altitude science missions flown over various parts of the world. They are also used for earth science and atmospheric sensor research and development, satellite calibration and data validation. The ER-2s are capable of carrying a maximum payload of 2,600 pounds of experiments in a nose bay, the main

  11. Bioinformatic analysis of an unusual gene-enzyme relationship in the arginine biosynthetic pathway among marine gamma proteobacteria: implications concerning the formation of N-acetylated intermediates in prokaryotes

    Directory of Open Access Journals (Sweden)

    Labedan Bernard

    2006-01-01

    Full Text Available Abstract Background The N-acetylation of L-glutamate is regarded as a universal metabolic strategy to commit glutamate towards arginine biosynthesis. Until recently, this reaction was thought to be catalyzed by either of two enzymes: (i the classical N-acetylglutamate synthase (NAGS, gene argA first characterized in Escherichia coli and Pseudomonas aeruginosa several decades ago and also present in vertebrates, or (ii the bifunctional version of ornithine acetyltransferase (OAT, gene argJ present in Bacteria, Archaea and many Eukaryotes. This paper focuses on a new and surprising aspect of glutamate acetylation. We recently showed that in Moritella abyssi and M. profunda, two marine gamma proteobacteria, the gene for the last enzyme in arginine biosynthesis (argH is fused to a short sequence that corresponds to the C-terminal, N-acetyltransferase-encoding domain of NAGS and is able to complement an argA mutant of E. coli. Very recently, other authors identified in Mycobacterium tuberculosis an independent gene corresponding to this short C-terminal domain and coding for a new type of NAGS. We have investigated the two prokaryotic Domains for patterns of gene-enzyme relationships in the first committed step of arginine biosynthesis. Results The argH-A fusion, designated argH(A, and discovered in Moritella was found to be present in (and confined to marine gamma proteobacteria of the Alteromonas- and Vibrio-like group. Most of them have a classical NAGS with the exception of Idiomarina loihiensis and Pseudoalteromonas haloplanktis which nevertheless can grow in the absence of arginine and therefore appear to rely on the arg(A sequence for arginine biosynthesis. Screening prokaryotic genomes for virtual argH-X 'fusions' where X stands for a homologue of arg(A, we retrieved a large number of Bacteria and several Archaea, all of them devoid of a classical NAGS. In the case of Thermus thermophilus and Deinococcus radiodurans, the arg(A-like sequence

  12. [Phylogenetic diversity and cold-adaptive hydrolytic enzymes of culturable psychrophilic bacteria associated with sea ice from high latitude ocean, Artic].

    Science.gov (United States)

    Yu, Yong; Li, Hui-Rong; Chen, Bo; Zeng, Yin-Xin; He, Jian-Feng

    2006-04-01

    The phylogenetic diversity of culturable psychrophilic bacteria associated with sea ice from high latitude sea (77 degrees 30'N - 81 degrees 12'N), Canadian Basin and Greenland sea Arctic, was investigated. A total of 37 psychrophilic strains were isolated using three different methods of ( i ) spread plate method: 100 microL of each dilution ice-melt sample was spreaded onto the surface of Marine 2216 agar (DIFCO laboratories, Detroit, MI) and incubated for 2 to 6 weeks at 4 degrees C; ( ii ) bath culture and spread plate method: 1 mL of sample was added to 9mL of NSW (unamended natural seawater, 0.2 microm prefiltered and autoclaved) and incubated for 1 months at - 1 degrees C, then spread plate method was used to isolate bacterial strains from the pre-cultured samples; ( iii ) cold shock, bath culture and spread plate method: samples were exposed to - 20 degrees C for 24h, then bacterial strains isolated by bath culture and spread plate method under aerobic conditions. Nearly half of psychrophilic strains are isolated by using method iii . 16S rDNA nearly full-length sequence analysis reveal that psychrophilic strains fall in two phylogenetic divisions, gamma-proteobacteria (in the genera Colwellia, Marinobacter, Shewanella, Thalassomonas, Glaciecola, Marinomonas and Pseudoalteromonas) and Cytophaga-Flexibacter-Bacteroides (in the genera Flavobacterium and Psychroflexus). Nine of bacterial isolates (BSi20007, BSi20497, BSi20517, BSi20537, BSi20170, BSi20001, BSi20002, BSi20675 and BSi20101) quite likely represent novel species (16S rDNA sequence similarity below 97%). One of strains (BSi20002) from Canadian Basin shows 100% sequence similarity to the Antarctic Weddell sea ice isolate Marinobacter sp. ANT8277, suggesting bacteria may have a bipolar distribution at the species level. AF283859 sequences were submitted to the BLAST search program of the National Center for Biotechnology Information website (NCBI, http://www. ncbi. nlm.nih. gov). Twenty sequences

  13. Using Natural Products to Treat Resistant and Persistent Bacterial Infections

    Science.gov (United States)

    Deering, Robert W.

    Antimicrobial resistance is a growing threat to human health both worldwide and in the United States. Most concerning is the emergence of multi-drug resistant (MDR) bacterial pathogens, especially the 'ESKAPE' pathogens for which treatment options are dwindling. To complicate the problem, approvals of antibiotic drugs are extremely low and many research and development efforts in the pharmaceutical industry have ceased, leaving little certainty that critical new antibiotics are nearing the clinic. New antibiotics are needed to continue treating these evolving infections. In addition to antibiotics, approaches that aim to inhibit or prevent antimicrobial resistance could be useful. Also, studies that improve our understanding of bacterial pathophysiology could lead to new therapies for infectious disease. Natural products, especially those from the microbial world, have been invaluable as resources for new antibacterial compounds and as insights into bacterial physiology. The goal of this dissertation is to find new ways to treat resistant bacterial infections and learn more about the pathophysiology of these bacteria. Investigations of natural products to find molecules able to be used as new antibiotics or to modulate resistance and other parts of bacterial physiology are crucial aspects of the included studies. The first included study, which is reported in chapter two, details a chemical investigation of a marine Pseudoalteromonas sp. Purification efforts of the microbial metabolites were guided by testing against a resistance nodulation of cell division model of efflux pumps expressed in E. coli. These pumps play an important role in the resistance of MDR Gram negative pathogens such as Pseudomonas aeruginosa and Enterobacteriaceae. Through this process, 3,4-dibromopyrrole-2,5-dione was identified as a potent inhibitor of the RND efflux pumps and showed synergistic effects against the E. coli strain with common antibiotics including fluoroquinolones, beta