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Wenjing Zhou - One of the best experts on this subject based on the ideXlab platform.
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sesquiterpenoids with antialgal activity against the common red tide microalgae from marine macroalga porphyra yezoensis
Environmental Science and Pollution Research, 2018Co-Authors: Yingying Sun, Jingzeng Xing, Jianshuo Zhang, Wenjing ZhouAbstract:Previous studies showed that methanol extracts from Porphyra yezoensis significantly inhibited Karenia mikimitoi and Skeletonema costatum. Five sesquiterpenoids (1-5) were successfully isolated from this marine macroalga through a combination of silica gel column chromatography and repeated preparative thin-layer chromatography in this paper. Their structure was identified as gossonorol (1), 7,10-epoxy-ar-bisabol-11-ol (2), cyclonerodiol (3), cadinol, (4) and 4-cadinen-1-ol (5) on the basis of spectroscopic data. These sesquiterpenoids were isolated from Porphyra yezoensis for the first time, and cyclonerodiol (3) and cadinol (4) isolated from marine Macroalgae for the first time. Further, a quantitative relationship between the inhibition of algal growth and the concentration of each antialgal sesquiterpenoid (gossonorol, 7,10-epoxy-ar-bisabol-11-ol and cyclonerodiol) was determined and important parameters, e.g., EC50-96h for future practical HAB control are to be obtained. Results showed that three sesquiterpenoids (1-3) had selective antialgal activity against the growth of red tide microalgae (Amphidinium carterae, Heterosigma akashiwo, Karenia mikimitoi, Phaeocystis globosa, Prorocentrum donghaiense, and Skeletonema costatum). More than two test red tide microalgae were significantly inhibited by these three sesquiterpenoids (1-3). Their antialgal activity against red tide microalgae has not been previously reported. Furthermore, EC50-96h of gossonorol (1) and 7,10-epoxy-ar-bisabol-11-ol (2) for specific test red microalgae were not only significantly less than 10 μg/mL, but also were smaller than/or very close to those of potassium dichromate. Gossonorol (1) and 7,10-epoxy-ar-bisabol-11-ol (2) possessed good application potential than potassium dichromate as a characteristic antialgal agent against the specific harmful red tide microalgae (Heterosigma akashiwo, Phaeocystis globosa, and Prorocentrum donghaiense) (or Heterosigma akashiwo and Karenia mikimitoi).
Thierry Perez - One of the best experts on this subject based on the ideXlab platform.
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Chemogeography of the red Macroalgae Asparagopsis: metabolomics, bioactivity, and relation to invasiveness
Metabolomics, 2017Co-Authors: Stephane Greff, Mayalen Zubia, Olivier P. Thomas, Claude Payri, Thierry PerezAbstract:Introduction The Latitudinal Gradient Hypothesis (LGH) foresees that specialized metabolites are overexpressed under low latitudes, where organisms are subjected to higher herbivory pressure. The widespread macroalga Asparagopsis taxiformis is composed of six distinct genetic lineages, some of them being introduced in many regions. Objectives To study (i) metabolic fingerprints of the macroalga and (ii) its bioactivity in space and time, both as proxies of its investment in defensive traits, in order to assess links between bioactivities and metabotypes with macroalgal invasiveness. Methods 289 macroalgal individuals, from four tropical and three temperate regions, were analyzed using untargeted metabolomics and the standardized Microtox® assay. Results Metabotypes showed a low divergence between tropical and temperate populations, while bioactivities were higher in temperate populations. However, these phenotypes varied significantly in time, with a higher variability in tropical regions. Bioactivities were high and stable in temperate regions, whereas they were low and much variable in tropical regions. Although the introduced lineage two exhibited the highest bioactivities, this lineage could also present variable proliferation fates. Conclusion The metabolomic approach partly discriminates macroalgal populations from various geographic origins. The production of chemical defenses assessed by the bioactivity assay does not match the macroalgal genetic lineage and seems more driven by the environment. The higher content of chemical defenses in temperate versus tropical populations is not in accordance with the LGH and cannot be related to the invasiveness of the Macroalgae.
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Chemogeography of the red Macroalgae Asparagopsis : metabolomics, bioactivity, and relation to invasiveness
Metabolomics, 2017Co-Authors: Stephane Greff, Mayalen Zubia, Olivier P. Thomas, Claude Payri, Thierry PerezAbstract:The Latitudinal Gradient Hypothesis (LGH) foresees that specialized metabolites are overexpressed under low latitudes, where organisms are subjected to higher herbivory pressure. The widespread macroalga Asparagopsis taxiformis is composed of six distinct genetic lineages, some of them being introduced in many regions. To study (i) metabolic fingerprints of the macroalga and (ii) its bioactivity in space and time, both as proxies of its investment in defensive traits, in order to assess links between bioactivities and metabotypes with macroalgal invasiveness. 289 macroalgal individuals, from four tropical and three temperate regions, were analyzed using untargeted metabolomics and the standardized Microtox® assay. Metabotypes showed a low divergence between tropical and temperate populations, while bioactivities were higher in temperate populations. However, these phenotypes varied significantly in time, with a higher variability in tropical regions. Bioactivities were high and stable in temperate regions, whereas they were low and much variable in tropical regions. Although the introduced lineage two exhibited the highest bioactivities, this lineage could also present variable proliferation fates. The metabolomic approach partly discriminates macroalgal populations from various geographic origins. The production of chemical defenses assessed by the bioactivity assay does not match the macroalgal genetic lineage and seems more driven by the environment. The higher content of chemical defenses in temperate versus tropical populations is not in accordance with the LGH and cannot be related to the invasiveness of the Macroalgae.
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The interaction between the proliferating macroalga Asparagopsis taxiformis and the coral Astroides calycularis induces changes in microbiome and metabolomic fingerprints
Scientific Reports, 2017Co-Authors: Stephane Greff, Olivier P. Thomas, Aschwin H Engelen, Tania Aires, Ester A. Serrao, Thierry PerezAbstract:Mediterranean Sea ecosystems are considered as hotspots of biological introductions, exposed to possible negative effects of non-indigenous species. In such temperate marine ecosystems, Macroalgae may be dominant, with a great percentage of their diversity represented by introduced species. Their interaction with temperate indigenous benthic organisms have been poorly investigated. To provide new insights, we performed an experimental study on the interaction between the introduced proliferative red alga Asparagopsis taxiformis and the indigenous Mediterranean coral Astroides calycularis. The biological response measurements included meta-barcoding of the associated microbial communities and metabolomic fingerprinting of both species. Significant changes were detected among both associated microbial communities, the interspecific differences decreasing with stronger host interaction. No short term effects of the macroalga on the coral health, neither on its polyp activity or its metabolism, were detected. In contrast, the contact interaction with the coral induced a change in the macroalgal metabolomic fingerprint with a significant increase of its bioactivity against the marine bacteria Aliivibrio fischeri. This induction was related to the expression of bioactive metabolites located on the macroalgal surface, a phenomenon which might represent an immediate defensive response of the macroalga or an allelopathic offense against coral.
Michael T Burrows - One of the best experts on this subject based on the ideXlab platform.
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Macroalgae contribute to the diet of patella vulgata from contrasting conditions of latitude and wave exposure in the uk
Marine Ecology Progress Series, 2016Co-Authors: Gillian M Notman, Rona A R Mcgill, Stephen J Hawkins, Michael T BurrowsAbstract:Analysis of gut contents and stable isotope composition of intertidal limpets (Patella vulgata) showed a major contribution of Macroalgae to their diet, along with microalgae and invertebrates. Specimens were collected in areas with limited access to attached Macroalgae, suggesting a major dietary component of drift algae. Gut contents of 480 animals from 2 moderately wave exposed and 2 sheltered rocky shores in each of 2 regions: western Scotland (55–56°N) and southwest England (50°N), were analysed in 2 years (n = 30 per site per year). The abundance of microalgae, Macroalgae and invertebrates within the guts was quantified using categorical abundance scales. Gut content composition was compared among regions and wave exposure conditions, showing that the diet of P. vulgata changes with both wave exposure and latitude. Microalgae were most abundant in limpet gut contents in animals from southwest sites, whilst leathery/corticated Macroalgae were more prevalent and abundant in limpets from sheltered and northern sites. P. vulgata appears to have a more flexible diet than previously appreciated and these keystone grazers consume not only microalgae, but also large quantities of Macroalgae and small invertebrates. To date, limpet grazing studies have focussed on their role in controlling recruitment of Macroalgae by feeding on microscopic propagules and germlings. Consumption of adult algae suggests P. vulgata may also directly control the biomass of attached Macroalgae on the shore, whilst consumption of drift algae indicates the species may play important roles in coupling subtidal and intertidal production.
Morten Foldager Pedersen - One of the best experts on this subject based on the ideXlab platform.
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spatio temporal distribution patterns of the invasive macroalga sargassum muticum within a danish sargassum bed
Helgoland Marine Research, 2006Co-Authors: Mads S. Thomsen, Thomas Wernberg, Peter A. Staehr, Morten Foldager PedersenAbstract:Sargassum muticum was first observed in Scandinavia in Limfjorden (Denmark) in 1984, where it is now the most abundant and conspicuous macroalga. Despite the ecological importance of Sargassum, few studies have described seasonal patterns within Scandinavian Sargassum beds. We quantified the dynamics of Macroalgae among years and seasons along a depth transect through a typical Sargassum bed in Limfjorden. The annual investigations (summer transects 1989–1999) showed a gradual increase in the dominance of Sargassum, especially at the 2–4-m depth interval. Significant seasonal dynamics in macroalgal abundance and assemblage structure were observed in this depth interval; the mean cover of Sargassum varied from ca. 5% (autumn and winter) to 25% (mid-summer). In comparison, encrusting algae had high and relatively stable covers throughout the year (ca. 20%). Other perennial Macroalgae had low mean covers ( 10 cm in diameter and species richness was negatively correlated to depth and stones 6 m) and small-scale (<1 m) depth differences where low light limits Sargassum at depth, physical disturbance and sediment stress limits Sargasum in shallow waters, and the presence of stable boulder substratum facilitate Sargassum. Competition for space from other Macroalgae and herbivory are probably of minor importance.
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Spatio-temporal distribution patterns of the invasive macroalga Sargassum muticum within a Danish Sargassum -bed
Helgoland Marine Research, 2005Co-Authors: Mads S. Thomsen, Thomas Wernberg, Peter A. Staehr, Morten Foldager PedersenAbstract:Sargassum muticum was first observed in Scandinavia in Limfjorden (Denmark) in 1984, where it is now the most abundant and conspicuous macroalga. Despite the ecological importance of Sargassum, few studies have described seasonal patterns within Scandinavian Sargassum beds. We quantified the dynamics of Macroalgae among years and seasons along a depth transect through a typical Sargassum bed in Limfjorden. The annual investigations (summer transects 1989–1999) showed a gradual increase in the dominance of Sargassum, especially at the 2–4-m depth interval. Significant seasonal dynamics in macroalgal abundance and assemblage structure were observed in this depth interval; the mean cover of Sargassum varied from ca. 5% (autumn and winter) to 25% (mid-summer). In comparison, encrusting algae had high and relatively stable covers throughout the year (ca. 20%). Other perennial Macroalgae had low mean covers ( 10 cm in diameter and species richness was negatively correlated to depth and stones 6 m) and small-scale (
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Size-dependent nitrogen uptake in micro- and Macroalgae
Marine Ecology Progress Series, 1995Co-Authors: Mette Hein, Morten Foldager Pedersen, Kaj Sand-jensenAbstract:The role of algal size as a controlling factor for nltrogen uptake kinetics is examined by comparing published values of N uptake rate and half-saturation constants in microand Macroalgae. The uptake kinetics differ substantially among algae very different in size. Microalgae take up nitrogen much faster per unit of biomass than Macroalgae at both high and low substrate concentrations, and microalgae have significantly higher affinity for nitrogen than Macroalgae. These typical differences in the uptake kinetics among small and large algae are commonly attributed to size-specific differences in the relative surface area (SA:V). Regression analysis demonstrates that size-specific variations in the kinetic parameters can be attributed to changes in relative surface area over an extensive range of algal sizes, covering both microand Macroalgae. These results agree with previously described relationships between maximum uptake rate of nutrients (nitrogen and phosphorus) and SA:V within narrow size-ranges (either phytoplankton or Macroalgae), and emphasize the existence of a general coupling between physiological and morpholog~cal properties in algae.
John A Harrison - One of the best experts on this subject based on the ideXlab platform.
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nitrogen loading alters seagrass ecosystem structure and support of higher trophic levels
Aquatic Conservation-marine and Freshwater Ecosystems, 2002Co-Authors: Linda A Deegan, Amos Wright, Suzanne G Ayvazian, John T Finn, Heidi E Golden, Rebeka R Merson, John A HarrisonAbstract:1. Anthropogenic-derived nutrient inputs to coastal environments have increased dramatically worldwide in the latter half of the 20th century and are altering coastal ecosystems. We evaluated the effects of nitrogen loading on changes in macrophyte community structure and the associated fauna of a north temperate estuary. We found that a shift in primary producers from eelgrass to Macroalgae in response to increased nutrient loading alters habitat physical and chemical structure and food webs. As nitrogen load increased we found increased macroalgal biomass, decreased eelgrass shoot density and biomass, decreased fish and decapod abundance and biomass, and decreased fish diversity. 2. The central importance of Macroalgae in altering eelgrass ecosystem support of higher trophic levels is evident in the response of the ecosystem when this component was manipulated. Removal of Macroalgae increased eelgrass abundance and water column and benthic boundary layer O2 concentrations. These changes in the physical and chemical structure of the ecosystem with lower macroalgal biomass resulted in higher fish and decapod abundance and biomass. 3. Both a 15N tracer experiment and the growth of fishes indicated that little of the macroalgal production was immediately transferred to secondary consumers. δ15N values indicated that the most abundant fishes were not using a grazing food web based on Macroalgae. Fish tended to grow better and have a greater survivorship in eelgrass compared to macroalgal habitats. 4. Watershed-derived nutrient loading has caused increased macroalgal biomass and degradation and loss of eelgrass habitat, thus reducing the capacity of estuaries to support nekton. Copyright © 2002 John Wiley & Sons, Ltd.
