69 research outputs found
Building your own mountain: the effects, limits, and drawbacks of cold-water coral ecosystem engineering
Framework-forming cold-water corals (CWCs) are ecosystem engineers that build mounds in the deep sea that can be up to several hundred metres high. The effect of the presence of cold-water coral mounds on their surroundings is typically difficult to separate from environmental factors that are not affected by the mounds. We investigated the environmental control on and the importance of ecosystem engineering for cold-water coral reefs using annotated video transect data, spatial variables (MEMs), and hydrodynamic model outputs in a redundancy analysis and with variance partitioning. Using available hydrodynamic simulations with cold-water coral mounds and simulations where the mounds were artificially removed, we investigated the effect of coral mound ecosystem engineering on the spatial configuration of reef habitat and discriminated which environmental factors are and which are not affected by the mounds.
We find that downward velocities in winter, related to non-engineered environmental factors, e.g. deep winter mixing and dense-water cascading, cause substantial differences in reef cover at the broadest spatial scale (20–30 km). Such hydrodynamic processes that stimulate the food supply towards the corals in winter seem more important for the reefs than cold-water coral mound engineering or similar hydrodynamic processes in summer. While the ecosystem-engineering effect of cold-water corals is frequently discussed, our results also highlight the importance of non-engineered environmental processes.
We further find that, due to the interaction between the coral mound and the water flow, different hydrodynamic zones are found on coral mounds that likely determine the typical benthic zonations of coral rubble at the mound foot, the dead coral framework on the mound flanks, and the living corals near the summit. Moreover, we suggest that a so-called Massenerhebung effect (well known for terrestrial mountains) exists, meaning that benthic zonation depends on the location of the mound rather than on the height above the seafloor or water depth. Our finding that ecosystem engineering determines the configuration of benthic habitats on cold-water coral mounds implies that cold-water corals cannot grow at deeper depths on the mounds to avoid the adverse effects of climate change.</p
Isolated limb perfusion for local gene delivery: efficient and targeted adenovirus-mediated gene transfer into soft tissue sarcomas
OBJECTIVE: To evaluate the potential of isolated limb perfusion (ILP) for
efficient and tumor-specific adenovirus-mediated gene transfer in
sarcoma-bearing rats. SUMMARY BACKGROUND DATA: A major concern in
adenovirus-mediated gene therapy in cancer is the transfer of genes to
organs other than the tumor, especially organs with a rapid cell turnover.
Adjustment of the vector delivery route might be an option creating tumor
specificity in therapeutic gene expression. METHODS: Rat hind limb
sarcomas (5-10 mm) were transfected with recombinant adenoviruses.
Intratumoral luciferase expression after ILP was compared with systemic
administration, regional infusion, or intratumoral injection using a
similar dose of adenoviruses carrying the luciferase marker gene.
Localization studies using lacZ as a marker gene were performed to
evaluate the intratumoral distribution of transfected cells after both ILP
and intratumoral injection. RESULTS: Intratumoral luciferase activity
after ILP or intratumoral administration was significantly higher compared
with regional infusion or systemic administration. After ILP, luciferase
gene expression was minimal in extratumoral organs, whether outside or
inside the isolated circuit. Localization studies demonstrated that
transfection was confined to tumor cells lying along the needle track
after intratumoral injection, whereas after ILP, lacZ expression was found
in viable tumor cells and in the tumor-associated vasculature.
CONCLUSIONS: Using ILP, efficient and tumor-specific gene transfection can
be achieved. The ILP technique might be useful for the delivery of
recombinant adenoviruses carrying therapeutic gene constructs to enhance
tumor control
The effect of high dose inhaled corticosteroids on wheeze in infants after respiratory syncytial virus infection: randomised double blind placebo controlled trial
Objective To determine whether early initiated anti-inflammatory therapy with prolonged high dose inhaled glucocorticoids influences the occurrence and severity of recurrent wheeze after respiratory syncytial virus related lower respiratory tract infections
Hydrography and food distribution during a tidal cycle above a cold-water coral mound
Cold-water corals (CWCs) are important ecosystem engineers in the deep sea that provide habitat for numerous species and can form large coral mounds. These mounds influence surrounding currents and induce distinct hydrodynamic features, such as internal waves and episodic downwelling events that accelerate transport of organic matter towards the mounds, supplying the corals with food. To date, research on organic matter distribution at coral mounds has focussed either on seasonal timescales or has provided single point snapshots. Data on food distribution at the timescale of a diurnal tidal cycle is currently limited. Here, we integrate physical, biogeochemical, and biological data throughout the water column and along a transect on the south-eastern slope of Rockall Bank, Northeast Atlantic Ocean. This transect consisted of 24-h sampling stations at four locations: Bank, Upper slope, Lower slope, and the Oreo coral mound. We investigated how the organic matter distribution in the water column along the transect is affected by tidal activity. Repeated CTD casts indicated that the water column above Oreo mound was more dynamic than above other stations in multiple ways. First, the bottom water showed high variability in physical parameters and nutrient concentrations, possibly due to the interaction of the tide with the mound topography. Second, in the surface water a diurnal tidal wave replenished nutrients in the photic zone, supporting new primary production. Third, above the coral mound an internal wave (200 m amplitude) was recorded at 400 m depth after the turning of the barotropic tide. After this wave passed, high quality organic matter was recorded in bottom waters on the mound coinciding with shallow water physical characteristics such as high oxygen concentration and high temperature. Trophic markers in the benthic community suggest feeding on a variety of food sources, including phytodetritus and zooplankton. We suggest that there are three transport mechanisms that supply food to the CWC ecosystem. First, small phytodetritus particles are transported downwards to the seafloor by advection from internal waves, supplying high quality organic matter to the CWC reef community. Second, the shoaling of deeper nutrient-rich water into the surface water layer above the coral mound could stimulate diatom growth, which form fast-sinking aggregates. Third, evidence from lipid analysis indicates that zooplankton faecal pellets also enhance supply of organic matter to the reef communities. This study is the first to report organic matter quality and composition over a tidal cycle at a coral mound and provides evidence that fresh high-quality organic matter is transported towards a coral reef during a tidal cycle
Xanthine Oxidase Activity of Arthrobacter X-4 cells Immobilized in Glutaraldehyde-Crosslinked Gelatin
Xanthine Oxidase Activity of Arthrobacter X-4 cells Immobilized in Glutaraldehyde-Crosslinked Gelatin
Structure of the capsular antigen of Neisseria meningitidis serogroup K
The capsular antigen isolated from the culture liquid of a Neisseria meningitidis serogroup K(1811) fermentation consists of the 2-acetamido-2-deoxymannuronic acid disaccharide repeating unit as follows: 3)-beta-d-ManpNAcA-(1->4)-beta-d-ManpNAcA-(1->
The polysaccharide is O-acetylated at the non-glycosylated C-4. Structural evidence has been obtained from sugar analysis, methylation analysis, as well as 1H and 13C NMR spectroscopy
Structure of the capsular antigen of Neisseria meningitidis serogroup K
The capsular antigen isolated from the culture liquid of a Neisseria meningitidis serogroup K(1811) fermentation consists of the 2-acetamido-2-deoxymannuronic acid disaccharide repeating unit as follows: 3)-beta-d-ManpNAcA-(1->4)-beta-d-ManpNAcA-(1->
The polysaccharide is O-acetylated at the non-glycosylated C-4. Structural evidence has been obtained from sugar analysis, methylation analysis, as well as 1H and 13C NMR spectroscopy
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