The Experts below are selected from a list of 219 Experts worldwide ranked by ideXlab platform
Anneke M. Breeman - One of the best experts on this subject based on the ideXlab platform.
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Effects of UV-B-induced DNA damage and photoinhibition on growth of temperate marine red macrophytes: Habitat-related differences in UV-B tolerance
Journal of Phycology, 2001Co-Authors: Willem H. Van De Poll, Anja Eggert, Anita G J Buma, Anneke M. BreemanAbstract:The sensitivity to UV-B radiation (UVBR: 280-315 nm) was tested for littoral (Palmaria palmata [L.] O. Kuntze, Chondrus crispus Stackhouse) and sublittoral (Phyllophora pseudoceranoides S. G. Gmelin, Rhodymenia pseudopalmata [Lamouroux] Silva, Phycodrys rubens [L.] Batt, Polyneura hilliae [Greville] Kylin) red macrophytes from Brittany, France. Algal fragments were subjected to daily repeated exposures of artificial UVBR that were realistic for springtime solar UVBR at the water surface in Brittany. Growth, DNA damage, photoinhibition, and UV-absorbing compounds were monitored during 2 weeks of PAR + UV-A radiation (UVAR) + UVBR, whereas PAR + UVAR and PAR treatments were used as controls. The littoral species showed a higher UV tolerance than the sublittoral species. After 2 weeks, growth of P. palmata and C. crispus was not significantly affected by UVBR, and DNA damage, measured as the number of cyclobutane-pyrimidine dimers per 10 6 nucleotides, was negligible. Photoinhibition, determined as the decline in optimal quantum yield, was low and decreased during the course of the experiment, coinciding with the production of UV-absorbing compounds in these species. In contrast, no UV-absorbing compounds were induced in the sublittoral species. Growth rates of P. pseudoceranoides and R. pseudopalmata were reduced by 40% compared with the PAR treatment. Additionally, constant levels of DNA damage and pronounced photoinhibition were observed after the UVBR treatments. Growth was completely halted for Phycodrys rubens and Polyneura hilliae, whereas DNA damage accumulated in the course of the experiment. Because Phycodrys rubens and Polyneura hilliae showed the same degree of photoinhibition as the other sublittoral species, it appears that the accumulation of DNA damage may have been responsible for the complete inhibition of growth. The results suggest an important role of DNA repair pathways in determining the UV sensitivity in red macrophytes.
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efficient photoreactivation of uvbr induced dna damage in the sublittoral macroalga Rhodymenia pseudopalmata rhodophyta
European Journal of Phycology, 2000Co-Authors: Hans Pakker, Chantal A C Beekman, Anneke M. BreemanAbstract:Repair of DNA damage induced by ultraviolet-B radiation (UVBR) was investigated in the sublittoral red alga Rhodymenia pseudopalmata at different temperatures, using immunofluorescent detection of thymine dimers. Photoreactivation of thymine dimers was completed within about 3 h at 6, 12 and 18 °C in the presence of ultraviolet-A radiation (UVAR) and photosynthetically active radiation (PAR) but no repair was found in dark-incubated fragments after 16–17 h. In plants previously exposed to a low UVBR dose (biologically effective dose: BEDDNA300 = 1.6 kJ m−2; unweighted irradiance = 0.72 W m−2 for 4 h), photoreactivation started within the first hour under UVAR + PAR at 18 °C but repair only started after 1–2 h at 12 and 6 °C. At 6 °C, repair was more efficient after exposure to a high UVBR dose (BEDDNA300 = 3.9 kJ m−2; unweighted irradiance = 0.78 W m−2 for 5 h) than to a lower dose (BEDDNA300 = 1.6 kJ m−2); no such difference was found at 18 °C. It is concluded that R. pseudopalmata is able to repair DNA ...
Gary W Saunders - One of the best experts on this subject based on the ideXlab platform.
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molecular assisted alpha taxonomy of the genus Rhodymenia Rhodymeniaceae Rhodymeniales from australia reveals overlooked species diversity
European Journal of Phycology, 2016Co-Authors: Gina V. Filloramo, Gary W SaundersAbstract:AbstractA previously published DNA barcode survey of red macroalgae in Australia revealed significant cryptic and overlooked diversity for the genus Rhodymenia with recognition of R. novahollandica, R. prolificans, R. stenoglossa, R. wilsonis and an additional four uncharacterized genetic species groups. Since that study, increased sampling effort in Australia has warranted reassessment and reinvestigation of the number of genetic species groups attributed to Rhodymenia and their respective taxonomic affiliations. Using molecular-assisted alpha taxonomy employing the DNA barcode (COI-5P), the present study resolved 188 Australian specimens in 12 genetic species groups assignable to the genus Rhodymenia. Four of these groups were attributed to the previously recognized species (above), whereas some collections from Lord Howe Island were attributed to the New Zealand species R. novazelandica, expanding its biogeographic range. The following seven genetic groups were inconsistent with existing species of Rho...
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Molecular-assisted alpha taxonomy of the genus Rhodymenia (Rhodymeniaceae, Rhodymeniales) from Australia reveals overlooked species diversity
2016Co-Authors: Gina V. Filloramo, Gary W SaundersAbstract:A previously published DNA barcode survey of red macroalgae in Australia revealed significant cryptic and overlooked diversity for the genus Rhodymenia with recognition of R. novahollandica, R. prolificans, R. stenoglossa, R. wilsonis and an additional four uncharacterized genetic species groups. Since that study, increased sampling effort in Australia has warranted reassessment and reinvestigation of the number of genetic species groups attributed to Rhodymenia and their respective taxonomic affiliations. Using molecular-assisted alpha taxonomy employing the DNA barcode (COI-5P), the present study resolved 188 Australian specimens in 12 genetic species groups assignable to the genus Rhodymenia. Four of these groups were attributed to the previously recognized species (above), whereas some collections from Lord Howe Island were attributed to the New Zealand species R. novazelandica, expanding its biogeographic range. The following seven genetic groups were inconsistent with existing species of Rhodymenia and established as novel taxa: R. compressa sp. nov., R. contortuplicata sp. nov., R. gladiata sp. nov., R. insularis sp. nov., R. lociperonica sp. nov., R. norfolkensis sp. nov. and R. womersleyi sp. nov. Although morphological and biogeographic features were adequate for distinguishing some species of Rhodymenia from Australia, DNA sequencing in combination with morphology and biogeography provided the most reliable means of identification.
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small subunit rrna gene sequences from representatives of selected families of the gigartinales and Rhodymeniales rhodophyta 1 evidence for the plocamiales ord nov
Botany, 1994Co-Authors: Gary W Saunders, G T KraftAbstract:Nucleotide sequences of the nuclear, small-subunit (SSU) ribosomal RNAs, as inferred from polymerase chain reaction (PCR)-amplified products, are presented for Areschougia congesta (Turner) J. Agardh (Solieriaceae), Dasyphloea insignis Montagne (Dumontiaceae), Sarcothalia crassifolia (C. Agardh) Edyvane & Womersley (Gigartinaceae), Nizymenia australis Sonder (Nizymeniaceae), Phacelocarpus peperocarpos (Poiret) Wynne, Ardre & Silva (Phacelocarpaceae), Plocamiocolax pulvinata Setchell, Plocamium angustum (J. Agardh) J.D. Hooker, Plocamium cartilagineum (Linnaeus) Dixon (Plocamiaceae), Rhodymenia linearis J. Agardh (Rhodymeniaceae), and Sphaerococcus coronopifolius Stackhouse (Sphaerococcaceae). Phylogenetic analyses of the SSU sequences between the Plocamiaceae and members of the Sphaerococcaceae, Phacelocarpaceae, and Nizymeniaceae, with which the Plocamiaceae has been associated historically, show SSU differences of between 87 and 105 nucleotides and do not indicate a close relationship. A review of anato...
Jane Prince - One of the best experts on this subject based on the ideXlab platform.
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the effects of light and thallus scour from ecklonia radiata canopy on an associated foliose algal assemblage the importance of photoacclimation
Marine Biology, 2004Co-Authors: Benjamin D Toohey, Sairah Y Malkin, J.c. Phillips, Thomas Wernberg, Gary A Kendrick, Jane PrinceAbstract:Kelp canopies have long been recognised for their influence on the structure of algal assemblages on sublittoral reefs. In Marmion Lagoon, Western Australia, we investigated how a canopy of the small kelp Ecklonia radiata affected the associated foliose algal assemblage and what potential mechanisms were responsible for the effects we observed. Light levels and physical abrasion (thallus scour) by an E. radiata canopy were manipulated in an orthogonal fixed-factor experiment that revealed that changes in light, but not thallus scour, had a significant effect on the composition of the algal assemblage. Reduced light levels were associated with a decrease in the Shannon-Wiener diversity index and an increased dominance of the foliose algae Pterocladia lucida and Rhodymenia sonderi. Photobiological investigations of three foliose species, P. lucida, R. sonderi and Chauviniella coriifolia indicated that they were able to photoacclimate to low light levels by increasing thallus absorption by up to 11%. Photoacclimation was also evident by an increase in the maximum rate of electron transport under low-light conditions. We conclude that the E. radiata canopy in Marmion Lagoon structures the foliose algal assemblage through the modification of the light environment and that this effect may be mediated by differences in the ability of different species of foliose algae to photoacclimate.
Daniel Robledo - One of the best experts on this subject based on the ideXlab platform.
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stress tolerance and photoadaptation to solar radiation in Rhodymenia pseudopalmata rhodophyta through mycosporine like amino acids phenolic compounds and pigments in an integrated multi trophic aquaculture system
Algal Research-Biomass Biofuels and Bioproducts, 2019Co-Authors: Hugo Pliegocortes, Yolanda Freilepelegrin, Gilles Bedoux, Romain Boulho, Laure Taupin, Nathalie Bourgougnon, Daniel RobledoAbstract:Abstract Rhodymenia pseudopalmata lives in the intertidal zone receiving high doses of solar radiation, including the potentially harmful UVR. Previous studies proved it ability to adapt to different artificial light intensities and salinity concentrations. The aim of this study was to describe the differences on the Mycosporine-like amino acids (MAAs), phenolic compounds, and pigments of R. pseudopalmata due to exposure to high solar radiation. Vegetative thalli were exposed to solar radiation using a Solar Exposure Chambers System (SECS) under an Integrated Multi-Trophic Aquaculture (IMTA) approach with marine fish culture. Samples from natural populations in Playa de Carmen, Mexico were included as reference. The biosynthesis of MAAs, and phenolic compounds were stimulated as a response to the stress caused by the exposure to high solar irradiation. Liquid Chromatography-Mass Spectrometry (LC-MS) revealed seven MAAs and their precursor deoxygadusol. Five MAAs were partially characterized through MS2 and fragmentation patterns suggested a common fragmentation pattern pathway. After seven days (D7), the MAAs total content was significant five-fold higher compared to wild populations (0.26 ± 0.1 mg g−1 DW). The Individual composition increased from four MAAs at D0, up to eight at D7, including deoxygadusol, palythene and usujirene, MAAs with high antioxidant activity. At D7, phenolic compounds increased up to 20%, and the 2, 2-diphenyl-1-picrylhydrazyl (DPPH) antioxidant activity reduced the IC50 to 4.0 ± 0.6 mg mL−1. The pigment content, Phycoerythrin (PE):Chl-a, and MAAs:Chl-a ratios might confer a unique photoprotection role from PE and MAAs to Chl-a. Similarly, Fv/Fm which was adapted to the variations of Photosynthetic Active Radiation (PAR) indicated a process of dynamic photoinhibition. Overall, our results evidenced the ability of this species to tolerate the stress to high solar irradiance and suggested the photoadaptation of the thalli. Farming possibilities, expected MAAs productivity, potential applications of MAAs and ecological considerations are also discussed.
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growth biochemical and antioxidant content of Rhodymenia pseudopalmata Rhodymeniales rhodophyta cultivated under salinity and irradiance treatments
Journal of Applied Phycology, 2017Co-Authors: Hugo Pliegocortes, Edgar Caamalfuentes, Jorge Monteromunoz, Yolanda Freilepelegrin, Daniel RobledoAbstract:Growth, biochemical composition and antioxidant capacity of Rhodymenia pseudopalmata were studied under controlled laboratory conditions. Cultures were exposed to five salinities ranging from 20, 25, 30, 35 and 40 psu under three photosynthetic active radiations (PAR) 50, 100 and 200 μmol photons m-2s-1. Rhodymenia pseudopalmata daily growth rates were significantly higher at 20 psu and high PAR, and decreased at 40 psu and low PAR. Chl a and PE contents were lower at high PAR. The carbohydrate content increased up to 54 % DW-1 under high PAR and 20 psu. Protein ranged from 4.9 to 10.5 % DW-1. Sixteen amino acids were detected in R. pseudopalmata under the experimental conditions tested. Glutamic acid, proline and methionine may act as osmolytes, while histidine, methionine and tyrosine may be involved in R. pseudopalmata antioxidant capacity. Rhodymenia pseudopalmata grown under high PAR and 20 psu had the highest increase in total phenolic compounds. Moreover, DPPH radical scavenging activity increased at 20, 25 and 40 psu under low PAR, and at 20 psu under high PAR. These results may partly explain the ability of R. pseudopalmata to grow under extreme conditions at the intertidal and its acclimation for mariculture.
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lipid characterization of red alga Rhodymenia pseudopalmata Rhodymeniales rhodophyta
Phycological Research, 2017Co-Authors: Edith Peraltagarcia, Edgar Caamalfuentes, Daniel Robledo, Emmanuel Hernandeznunez, Yolanda FreilepelegrinAbstract:SUMMARY Rhodymenia pseudopalmata is a red alga that grows at the Caribbean coast of the Yucatan Peninsula and has been proven successful in cultivation. In this study we present the lipid composition of R. pseudopalmata collected from wild populations during three different seasons of 2013. Cultured material was also analyzed and compared in order to evaluate its value as feedstock for biotechnological uses. Thin layer chromatography, 1 H and 13 C NMR spectroscopy and gas chromatography-mass spectrometry were used to assess variations in their lipid composition. Our results showed that the dominant lipid classes were phospholipids both in wild and cultured materials. The phospholipids phosphatidylcholine and phosphatidylglycerol and the glycolipid monogalactosyldiacylglycerol were present in both wild and cultured R. pseudopalmata, whereas the phospholipid lysophosphatidylcholine was only found in wild material. Fatty acids (FAs) showed a high monounsaturated FAs (MUFAs) content with oleic acid (C18:1ω9) as the dominant compound (78 and 94% of the MUFAs for wild and culture materials, respectively). Saturated FAs (SFAs) represented approximately 90% of the total fatty acid content, with palmitic acid (C16:0) reaching approximately 83% of the SFA content. Rhodymenia pseudopalmata was low in polyunsaturated FAs when compared to other red algae. Other compounds such as 1-heptadecene, 1-hexadecene, 15-heptadecenal, 3-eicosene 6,10,14-trimethyl-2-pentadecanone, phytol, and heptadecane were also found. Lipid composition differences between the wild and cultured algae suggest that light and nutrients can be manipulated to modify lipid composition. Based on its lipid composition and cultivation feasibility, R. pseudopalmata could be a potential source for nutraceuticals and biofuels production.
Hans Pakker - One of the best experts on this subject based on the ideXlab platform.
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efficient photoreactivation of uvbr induced dna damage in the sublittoral macroalga Rhodymenia pseudopalmata rhodophyta
European Journal of Phycology, 2000Co-Authors: Hans Pakker, Chantal A C Beekman, Anneke M. BreemanAbstract:Repair of DNA damage induced by ultraviolet-B radiation (UVBR) was investigated in the sublittoral red alga Rhodymenia pseudopalmata at different temperatures, using immunofluorescent detection of thymine dimers. Photoreactivation of thymine dimers was completed within about 3 h at 6, 12 and 18 °C in the presence of ultraviolet-A radiation (UVAR) and photosynthetically active radiation (PAR) but no repair was found in dark-incubated fragments after 16–17 h. In plants previously exposed to a low UVBR dose (biologically effective dose: BEDDNA300 = 1.6 kJ m−2; unweighted irradiance = 0.72 W m−2 for 4 h), photoreactivation started within the first hour under UVAR + PAR at 18 °C but repair only started after 1–2 h at 12 and 6 °C. At 6 °C, repair was more efficient after exposure to a high UVBR dose (BEDDNA300 = 3.9 kJ m−2; unweighted irradiance = 0.78 W m−2 for 5 h) than to a lower dose (BEDDNA300 = 1.6 kJ m−2); no such difference was found at 18 °C. It is concluded that R. pseudopalmata is able to repair DNA ...