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The brown alga Pelvetia canaliculata is one of the species successfully adapted to intertidal conditions. Inhabiting the high intertidal zone, Pelvetia spends most of its life exposed to air, where it is subjected to desiccation, light, and temperature stresses. However, the physiological and biochemical mechanisms allowing this alga to tolerate such extreme conditions are still largely unknown. The objective of our study is to compare the biochemical composition of Pelvetia during the different phases of the tidal cycle. To our knowledge, this study is the first attempt to draft a detailed biochemical network underneath the complex physiological processes, conferring the successful survival of this organism in the harsh conditions of the high intertidal zone of the polar seas. We considered the tide-induced changes in relative water content, stress markers, titratable acidity, pigment, and phlorotannin content, as well as the low molecular weight metabolite profiles (GC-MS-based approach) in Pelvetia thalli. Thallus desiccation was not accompanied by considerable increase in reactive oxygen species content. Metabolic adjustment of P. canaliculata to emersion included accumulation of soluble carbohydrates, various phenolic compounds, including intracellular phlorotannins, and fatty acids. Changes in titratable acidity accompanied by the oscillations of citric acid content imply that some processes related to the crassulacean acid metabolism (CAM) may be involved in Pelvetia adaptation to the tidal cycle.

During high tide, macroalgae are submersed, facing adequate environmental conditions, however, at low tide, these species can be exposed to high UV radiation and desiccation, leading to an overproduction of reactive oxygen species, causing oxidative stress. Since intertidal organisms present differential sensitivity to abiotic fluctuations, this study aimed to evaluate the physiological responses [photosynthetic pigments, hydrogen peroxide (H2O2), lipid peroxidation (LP), and thiols and proline] of three macroalgae, from different intertidal levels, towards tidal regimes. Samples of Pelvetia canaliculata, Ascophyllum nodosum, and Fucus serratus were collected from beaches located on the southern limit of distribution in periods of potential stress (Summer and Spring), under low and high tide. The photosynthetic pigments of P. canaliculata and F. serratus were generally higher during low tide, and the oxidative damage evidenced by H2O2 and LP increased in the Summer, while A. nodosum showed greater oxidative damage in the Spring. While thiol content did not change, proline levels were species- and tidal-specific among sampling dates. P. canaliculata presented higher resilience to unfavorable conditions, while F. serratus was the most sensitive species. The physiological responses analyzed were species-specific, pointing to the high susceptibility of low intertidal organisms to expected extreme climatic events.

Brown algae, rich in antioxidants and other bioactive compounds, are important dietary seaweeds in many cultures. Like other marine macroalgae, brown seaweeds are known to accumulate the halogens iodine and bromine. Comparatively little is known about the chemistry of chlorine in seaweeds. We used synchrotron-based X-ray absorption spectroscopy to measure total non-volatile organochlorine and -bromine in five edible brown seaweeds: Laminaria digitata, Fucus vesiculosus, Pelvetia canaliculata, Saccharina latissima, and Undaria pinnatifida. Organochlorine concentrations range from 120 to 630 mg·kg−1 dry weight and organobromine from 150 to 360 mg·kg−1, comprising mainly aromatic organohalogens in both cases. Aliphatic organochlorine exceeds aliphatic organobromine but is positively correlated with it among the seaweeds. Higher organochlorine levels appear in samples with more lipid moieties, suggesting lipid chlorination as a possible formation pathway. Particulate organohalogens are not correlated with antioxidant activity or polyphenolic content in seaweed extracts. Such compounds likely contribute to organohalogen body burden in humans and other organisms.

Accumulation of biologically active metabolites is a specific feature of plant biochemistry, directing the use of plants in numerous applications in the pharmaceutical and food industries. Among these substances, the plethora of phenolic compounds has attracted particular interest among researchers. Here, we report on new findings in phlorotannin research, a large group of multifunctional phenolic substances, produced in brown algae. Comprehensive LC-MS profiling of three algal species allowed us to depict the complex pattern of this structurally diverse compound group across different tissues and subcellular compartments. We compiled more than 30 different phlorotannin series in one sample and used accurate mass spectrometry to assign tentative structures to the observed ions based on the confirmed sum formulas. From that, we found that acetylation, hydroxylation, and oxidation are likely to be the most common in vivo modifications to phlorotannins. Using an alternative data mining strategy to cope with extensive coelution and structural isomers, we quantitatively compared the intensity of different phlorotannin series in species, tissues, and subcellular compartments to learn more about their physiological functions. The structure and intra-thallus profiles of cell wall-bound phlorotannins were studied here for the first time. We suggest that one of the major dibenzodioxin-type phlorotannin series may exclusively target integration into the cell wall of fucoid algae.

Accumulation of biologically active metabolites is a specific feature of plant biochemistry, directing the use of plants in numerous applications in the pharmaceutical and food industries. Among these substances, the plethora of phenolic compounds has attracted particular interest among researchers. Here, we report on new findings in phlorotannin research, a large group of multifunctional phenolic substances, produced in brown algae. Comprehensive LC-MS profiling of three algal species allowed us to depict the complex pattern of this structurally diverse compound group across different tissues and subcellular compartments. We compiled more than 30 different phlorotannin series in one sample and used accurate mass spectrometry to assign tentative structures to the observed ions based on the confirmed sum formulas. From that, we found that acetylation, hydroxylation, and oxidation are likely to be the most common in vivo modifications to phlorotannins. Using an alternative data mining strategy to cope with extensive coelution and structural isomers, we quantitatively compared the intensity of different phlorotannin series in species, tissues, and subcellular compartments to learn more about their physiological functions. The structure and intra-thallus profiles of cell wall-bound phlorotannins were studied here for the first time. We suggest that one of the major dibenzodioxin-type phlorotannin series may exclusively target integration into the cell wall of fucoid algae.

In order to increase the methane yield from biomass, this paper investigates the mechanical pretreatment effect of a Hollander beater on the anaerobic digestion process of Pelvetia canaliculata macroalgae using a response surface methodology (RSM). Higher values on methane yield were obtained at lower F/I ratios, with an increase up to 2.5-fold at an F/I value of 0.3. A multi-objective optimization study was carried out with the aim of maximizing the methane yield while minimizing the pretreatment time. An optimum methane yield of 283 ml/gVS was obtained for 50 min pretreatment time and a ratio F/I of 0.3, which represents an increase of 45% compared to non-pretreated algae.

© The Author(s)., This study was designed to analyze the chemical composition and in vitro rumen fermentation of eight seaweed species (Brown: Alaria esculenta, Laminaria digitata, Pelvetia canaliculata, Saccharina latissima; Red: Mastocarpus stellatus, Palmaria palmata and Porphyra sp.; Green: Cladophora rupestris) collected in Norway during spring and autumn. Moreover, the in vitro ruminal fermentation of seventeen diets composed of 1:1 oat hay:concentrate, without (control diet) or including seaweeds was studied. The ash and N contents were greater (p < 0.001) in seaweeds collected during spring than in autumn, but autumn-seaweeds had greater total extractable polyphenols. Nitrogen in red and green seaweeds was greater than 2.20 and in brown seaweeds, it was lower than 1.92 g/kg DM. Degradability after 24 h of fermentation was greater in spring seaweeds than in autumn, with Palmaria palmata showing the greatest value and Pelvetia canaliculata the lowest. Seaweeds differed in their fermentation pattern, and autumn Alaria esculenta, Laminaria digitata, Saccharina latissima and Palmaria palmata were similar to high-starch feeds. The inclusion of seaweeds in the concentrate of a diet up to 200 g/kg concentrate produced only subtle effects on in vitro ruminal fermentation., This research was funded by the Excellence Programme of Junta de Andalucia, Spain (grant number P12-AGR-587) and y the Research Council of Norway (grant number233682/E50).

A mechanistic and phenomenological model for multi-component cation exchange has been applied in order to describe the dynamic behavior of barium removal by seaweeds in batch and fixed-bed systems, instead of the empirical models usually applied. Initially, four macroalgae were tested as natural cation exchangers for barium removal: Arribadas, Gracilaria birdiae, Pelvetia canaliculata and Sargassum cymosum. Brown alga Pelvetia canaliculata showed the highest barium uptake capacity, mainly associated with the amount of carboxylic and sulfonic groups present in the biomass surface. A mechanistic model based on the mass action law was able to predict the cation exchange equilibrium for the Ba2+/Ca2+/H+ multi-component system, being able to determine the selectivity coefficients between all ionic species for the functional groups. The Pelvetia canaliculata in the calcium form, after acid pre-treatment was used for fixed-bed column tests. The operating capacity was 1.85 mEq/g (237 BV), treating 14 L of influent (0.45 L/g of natural resin) until the breakthrough point. Elution in counter-flow mode, using 1.0 M HCl as eluent, was fast and efficient (100%), using only 5 BV of eluent (181 g HCl/L resin; eluant ratio of 520%). The mass transfer model proposed, considering equilibrium given by the mass action law, was able to predict well the ion exchange process in batch or continuous operation mode during the saturation and elution steps for all chemical species in the liquid and solid phase.

This paper reports a treatment strategy for an electroplating wastewater containing high amounts of hexavalent and trivalent chromium and zinc, and residual iron. The brown macroalga Pelvetia canaliculata was used as a natural electron donor for the reduction of Cr(VI) to Cr(III) at acidic pH, and as a natural cation exchanger for zinc, iron and trivalent chromium sequestration. The strategy adopted for the wastewater treatment involves: (i) the reduction of Cr(VI) to Cr(III) using the macroalga as electron donor; (ii) trivalent chromium, zinc and iron precipitation at pH 8.5; and (iii) the removal of residual zinc ions (13 mg/L) by cation exchange at pH 8.5, using the negatively charged functional groups present at the surface of P. canaliculata . The Cr(VI) reduction was evaluated as a function of the biomass and Cr(VI) concentration, pH and temperature. The reaction was promoted through biomass oxidation in acidic medium. The Cr(VI) reduction capacities of raw and protonated P. canaliculata were around 1.8 and 2.3 mmol/g and the values for the Cr(III) uptake capacity of the oxidized biomass were 0.8 and 1.9 mmol/g, respectively. The results suggest that the oxidation of the biomass during Cr(VI) reduction generates new negatively charged active sites for cation binding. The continuous treatment of the wastewater containing Cr(VI) was evaluated in a column packed with raw P. canaliculata , and a maximum Cr(VI) reduction capacity of around 2.1 mmol/g was achieved. After the Cr(VI) removal step, 100% (below the detection limit) and 95% of the remaining trivalent chromium and zinc, respectively, can be eliminated by precipitation at pH 8.5.

The use of seaweeds in animal diets is not new. However, little is known about the feed value of seaweed, both in terms of chemical composition and protein digestibility, and regarding variation between species and season. In this study, eight seaweed species of the genus Acrosiphonia, Alaria, Laminaria, Mastocarpus, Palmaria, Pelvetia, Porphyra, and Ulva were sampled in spring (March) and autumn (October and November) 2014 at the coast of Bodø in Northern Norway, and were analysed for chemical composition, in situ rumen degradability and total tract crude protein (CP) digestibility. Ash content in dry matter (DM) was generally high (overall mean 190 g/kg in DM) and varied considerably, between species (P

Understanding the mechanism by which a fertilized egg establishes an embryonic axis is of fundamental importance to the study of developmental biology. Much of what we have learned about axis formation in plants derives from investigations of fucoid algae. In this report I review the data concerning the role of Ca2+ in the early development of Fucus and Pelvetia. The evidence shows that Ca2+ plays an important role in germination and rhizoid growth, but its function in polarization remains uncertain.

The polarity of fucoid eggs is fixed when rhi zoidal growth starts. A steady flow of calcium ions into the incipient tip is thought to establish a high calcium zone, which is needed for tip formation and outgrowth. To test this model, we injected six different BAPTA-type calcium buffers into Pelvetia eggsat about 3 to 7 h before outgrowth normally starts. Critical final cell concentra tion ofeach buffer proves to block outgrowth (as well as cell division) for up to two weeks. The critical inhibitory concentration falls as the cal cium dissociation constant, KD, rises (and the buffers weaken) in the series of five buffers from 5,5' dimethyl bapta (KD 0.4 @LM) to 4,4' difluoro-bapta (KD= 5 SM); then finally rises again with the weakest buffer tested, 5,5' methylnitro-bapta (KD = 60 MM).Thus calcium buffers with a KDofabout 5 @Mprove most effective in blocking development. The effects of injecting a buffer do not de pend upon the amount ofcoinjected calcium. To analyze these results, we imagine that each buffer acts to facilitate free calcium diffusion and thus sup presses gradient formation. This model leads to an exact equation and prediction ofthe concentrations of various buffers needed to inhibit development. The data fit this equation rather well ifit is assumed that the free calcium concentration in the incipient tip is normally kept at about 10 @M and thus far above the general cytosolic level.

Patterns of hydrogen peroxide content and vanadium-dependent haloperoxidase (V-HPO) activity were investigated in thalli of six species of Fucales (Fucus vesiculosus, F. serratus, F. edentatus, F. distichus, Ascophyllum nodosum and Pelvetia canaliculata). H2O2 levels in all species were similar to those of photosynthesizing tissues of unstressed terrestrial plants. The highest H2O2 content (up to 0.7 μM g FW−1) was in F. distichus and Pelvetia. H2O2 content in the basal and middle zones of fronds was generally higher than in vegetative apices and receptacles. Similar trends were detected for V-HPO activity with both bromide and iodide. Intrathallus profiles of H2O2 content and V-HPO activity may be attributed to the physiological condition of the respective thallus zones, i.e. photosynthetic activity and stage of cell differentiation. Steady-state kinetics showed significant variation of V-HPO parameters between fucoid species, suggesting that they contain different forms of the enzyme. V-HPO fr...

Aims Screening of seaweed-associated bacteria capable of producing antimicrobials. Methods and results Fifteen microbial strains, associated to the brown seaweed Pelvetia canaliculata (Linnaeus) attached to the rocks of Sonmiani Beach (Karachi, Pakistan), were screened. Crude extract filtrates of CMG S2 strain grew on Zobell marine agar (ZMA) had the most remarkable antimicrobial activity. Based on its phenotypic aspects (e.g. Gram-positive, microccoid form), biochemical characteristics (e.g. halotolerance) and genetic analyses, CMG S2 is identified as a putatively new Kocuria marina type strain belonging to the actinobacteria’s class and micrococcaceae family. Thereby, the nucleotide sequence analysis of its full-length 16S ribosomal ribonucleic acid (rRNA) gene (GenBank accession number EU073966.1 ) displayed highest identity (i.e. 99%) and score (2630) with K. marina KMM 3905. Phylogenic trees analysis using the neighbor-joining method showed closest evolutionary distance of CMG S2 with KMM 3905 strain and K. carniphila (DC2201) specie. Interestingly, a unique ultraviolet (UV)-bioactive compound was purified from CMG S2 crude extracts by flash silica gel column and thin-layer chromatography (TLC) techniques. Its chemical structure was unraveled as 4-[(Z)-2 phenyl ethenyl] benzoic acid (PEBA, later named kocumarin) by nuclear magnetic resonance (NMR) spectroscopy techniques. Importantly, kocumarin demonstrated prominent and rapid growth inhibition against all tested fungi and pathogenic bacteria including methicillin-resistant Staphylococcus aureus (MRSA), with a minimal fungal inhibitory concentration (MFC) of 15–25 μg/mL and a minimal (bacterial) inhibitory concentration (MIC) of 10–15 μg/mL. Significance and impact of the study Kocumarin represents a new promising natural antibiotic for in vivo and environmental applications.

Author's accepted version (post-print). Available from 29/03/2018. Seaweeds have potentials as alternative feed for ruminants, but there is a limited knowledge on their nutritive value. Seven seaweed species collected along the coast above the Arctic circle of Norway, both in spring and autumn, were assessed for nutrients and total polyphenols (TEP) content, gas production kinetics and in vitro rumen fermentation in batch cultures of ruminal microorganisms. The seaweeds were three red species (Mastocarpus stellatus, Palmaria palmata and Porphyra sp.), three brown species (Alaria esculenta, Laminaria digitata and Pelvetia canaliculata) and one green species (Acrosiphonia sp.). Additionally, the abundance and diversity of total bacteria, protozoa and archaea in the cultures with the three red seaweeds collected in spring were analyzed by quantitative PCR and PCR-DGGE, respectively. The crude protein (CP) content varied widely. Pelvetia had the greatest (P 0.05) among the other seaweeds in VFA production, but Porphyra sp. had the second highest methane production (P 0.05) by either seaweed species or the collection season. Higher final pH (P 0.05) in the abundance or the diversity of total bacteria, protozoa and archaea. In the PCR-DGGE analysis, samples were separated by the incubation run for all microbial populations analyzed, but not by seaweed species. The results indicate that seaweed species differ markedly in their in vitro rumen degradation, and that samples collected in autumn had lower rumen degradability than those collected in spring.

Aim Species distributions have been continuously adjusting to changing climaticconditions throughout the glacial–interglacial cycles. In the marine realm, evidencesuggests that latitudinal range shifts, involving both spatial expansions and trailing-edge contractions, may represent a common response to climatic oscillations. Thebiogeographical histories of coastal organisms, however, have been inferredprimarily using molecular markers, potentially overlooking past range dynamicsbeyond contemporary rear edges. In this study we combined species distributionmodels (SDMs) and mitochondrial DNA (mtDNA) data to investigate the biogeo-graphical history of the high-intertidal seaweed Pelvetia canaliculata. We investi-gated the hypotheses that its distribution is set by both marine and terrestrialclimates and that its range has shifted northwards since the Last Glacial Maximum.Location North-eastern Atlantic intertidal from Portugal to Norway.Methods In total, 432 individuals at 27 sites covering the extant range of Pelvetiacanaliculata were sampled and sequenced for a c. 500 bp mtDNA intergenic spacer.A niche model was developed using marine and terrestrial variables. Range dynam-ics were reconstructed based on the geographical patterns of genetic variation andon the SDM projections for the Last Glacial Maximum (LGM) and the present.Results The best distribution models incorporated both marine and terrestrialvariables. LGM projections revealed suitable habitat between southern Moroccoand the periglacial shorelines of the Celtic Sea. Pelvetia canaliculata exhibited ahighly structured phylogeography, being subdivided into three largely disjunctlineages, two of them endemic to Iberia. The central/northern European lineageexhibited the highest haplotypic diversity and showed a consistent decline innucleotide diversity and haplotypic richness at higher latitudes.Main conclusions Assuming species/climate equilibrium, SDMs supportedthe hypothesis of a post-glacial latitudinal range shift. Molecular variationrevealed contrasting demographic behaviours in Iberian and periglacial regions.In Iberia the low haplotypic diversity suggested complex range dynamics thatare not fully captured by SDM projections. Periglacial regions, identified as thesource of poleward colonization, were inferred to have been comparativelymore stable. Greater attention should be paid to marine range dynamics atlow-latitude range margins, particularly in genetically structured low-dispersalspecies exhibiting southern endemic variation.KeywordsClimatic refugia, Last Glacial Maximum, north-eastern Atlantic, Pelvetia cana-liculata, phylogeography, range shift, species distribution model, trailing-edge.

Due to the established health benefits of omega-3 long-chain polyunsaturated fatty acids (LC-PUFA), there is a globally increasing demand for alternative natural resources with appropriate fatty acid profiles. To assess the suitability of macroalgae as a source, 16 species (nine Phaeophyceae, five Rhodophyta and two Chlorophyta) were collected at two seasons (June and November) from the Irish west Coast, and total fatty acid contents and specific profiles were determined. Total fatty acid contents, expressed per percentage of dry weight, ranged from 6.4 % ± 0.3 (Pelvetia canaliculata, Phaeophyceae) to 0.8 % ± 0.2 (Porphyra dioica, Rhodophyta). Most common fatty acids were palmitic (16:0), oleic (OLE, 18:1 n-9), α-linolenic (ALA, 18:3 n-3), arachidonic (ARA, 20:4 n-6) and eicosapentaenoic (EPA, 20:5 n-3) acids. Fatty acid profiles were highly variable between and within algal groups; red and brown seaweeds were generally richer in LC-PUFA (e.g. 20:4 n-6 and 20:5 n-3), while high levels of saturated fatty acids such as palmitic acid (16:0) were observed in green species. Most omega-3 PUFA-rich species investigated had a omega-6/omega-3 fatty acid ratio close to 1, which is favourable for human health. The two seasonal sampling times revealed significant differences in total fatty acid and 20:5 n-3 (EPA) contents, with changes depending on species, thus implying varying suitability as potential target species for EPA production. At both times of the year, Palmaria palmata was identified as most promising species as a source of 20:5 n-3 (EPA) amongst all species investigated, with levels ranging from 0.44 to 0.58 % of dry weight in June and November, respectively.

An efficient, food-friendly process for the enrichment of macroalgal phlorotannins from solid-liquid extracts (SLE) of three brown macroalgae, namely Fucus spiralis Linnaeus, Pelvetia canaliculata (Linnaeus) DecaisneThuret and Ascophyllum nodosum (Linnaeus) Le Jolis, has been demonstrated. The initial utilisation of molecular weight cut-off (MWCO) dialysis generated fractions of low molecular weight (LMW) (3.5 kDa) and of high molecular weight (HMW) (3.5-100 kDa and100 kDa) from cold water, hot water and aqueous ethanolic SLE extracts. An enhancement of the total phenolic content (TPC), radical scavenging abilities (RSA) and ferric reducing antioxidant power (FRAP) in the HMW fractions of 3.5-100 kDa and/or100 kDa from the cold water and aqueous ethanolic extracts was observed. The initial weak TPC, RSA and FRAP observed in the LMW fractions relative to the HMW fractions were substantially enhanced following a reverse-phase flash chromatography fractionation method. Quadrupole time-of-flight mass spectrometry (Q-Tof-MS) suggests that phlorotannins of varying degrees of phloroglucinol polymerisation are present in LMW fractions of the three brown macroalgal species. The development of a food-friendly process for the extraction and enrichment of phlorotannins from Irish macroalgae is vital to facilitate the use of this valuable resource in future developments of macroalgal-based functional foods.

In this study, brown macro-algae harvested from the north coast of Portugal, Laminaria hyperborea , Fucus spiralis , Pelvetia caniculata and Ascophyllum nodosum , were used as natural cation exchangers for the treatment of zinc-containing rinse waters generated in the galvanizing process. The zinc wastewater is characterized by a high conductivity (1.5 mS/cm), a low organic content and a zinc concentration of 10 mg/L, being approximately 80% and 20% in the form of Zn 2+ and ZnSO 4(aq) , respectively. Although the ion-exchange capacity of the four macro-algae is similar (2.2–2.4 mEq/g), mainly associated with the presence of weak acidic carboxylic and strong acidic sulfonic groups, L. hyperborea showed a higher selectivity for zinc ions. The uptake capacity for zinc ions is highly affected by the galvanic wastewater matrix, when compared with the performance using a pure zinc solution. Zinc uptake equilibrium, on all the natural cation exchangers, was well described by a linear relationship. Cation exchange kinetic was adequately represented by a mass transfer model, considering a linear driving force model for intraparticle diffusion. Na-loaded alga showed a higher affinity for zinc ions when compared with Ca-loaded alga and raw alga. HCl, HNO 3 , H 2 SO 4 and CaCl 2 eluents were tested for zinc displacement from exhausted algae. HNO 3 reached an elution efficiency of 100% in less time than the other eluents tested. After the acid elution, the resin was converted to Na or Ca form (Na- or Ca-H-loaded biomass), using NaCl and CaCl 2 solutions. Although the regenerated alga in the form of sodium showed a higher affinity for zinc ions, its physical deterioration after Na loading may affect its application in a full-scale treatment.

In the present work, various forms of algae Pelvetia canaliculata were prepared by different chemical modifications, in order to get the best form of algae for the maximum uptake of nickel. Potentiometric titration revealed that the carboxyl groups were more abundant (3.9 mmol/g) as compared to hydroxyl groups (2.0 mmol/g) on the biosorbent surface. Fourier transform infrared (FUR) analysis of algae was done to identify the role of different functional groups present on algae surface during nickel biosorption. The protonated algae showed least sorption of nickel suggesting that after acid treatment, some of the binding sites were destroyed. Among the various forms of prepared algae. Na-algae prepared directly from raw algae (without protonation) showed highest uptake of nickel. The release of sodium ions during the uptake of nickel ions has shown that the current biosorption mechanism involves ion-exchange being a stoichiometrical ratio of 2:1 between sodium and nickel ions.

Fucoid assemblages dominated by Pelvetia canaliculata, Fucus spiralis, F. vesiculosus, and Ascophyllum nodosum located at two sites on the central coast of Asturias (northern Spain) were sampled monthly in 1977. Repeating the same sampling methodology, a resurvey was done in 2007 to detect changes in the abundances of the species using the previous data as a baseline. Annual net primary production was lower for all the species in 2007, and there were differences in the timing of maximum biomass for P. canaliculata and F. vesiculosus, as well as a shortening of the growth period in 2007. Associated fauna also differed between dates. Higher abundances of Gibbula spp. occurred in 2007, whereas littorinid species densities in the upper intertidal were reduced in that year. As a result, the fucoid-grazers balance changed, with P. canaliculata and particularly F. vesiculosus, being the assemblages most sensitive to change. Observed modifications were not merely fluctuations in the biomass patterns of these species, but also responses to increases in air temperature and sea surface temperature and to a shift in the frequency and seasonality of upwelling episodes. Other long-term abiotic fluctuations not directly related to global warming should also be considered as possible drivers for these changes.

The stress tolerance ability of Pelvetia canaliculata (L.) Dcne. Et Thur. and Fucus spiralis L. to temporary and periodic emersion stress was examined in order to test the following hypotheses: The upper shore alga, P. canaliculata is more tolerant to desiccation than F. spiralis in the germling stage and the former outgrows the latter under desiccation stress; Germling stress tolerance of the two species is age-specific; Crowding of germlings protects them from desiccation, ir respective of the species involved. Germling growth of the two species was retarded with increasing exposure period and was age-specific, as they were air-exposed at an earlier stage. After 16 days, the length of Pelvetia germlings was similar between 2-day-old germlings (125-140 µm) and 7-day-old germlings (134-140 µm), which were air-exposed during the same period (0, 6, 12, 24, 48, and 72 h) at the two different ages. However, Fucus germlings were significantly larger at 7-day-old germlings (211-277 µm) than at 2-day-old germlings (184-278 µm), especially in the treatments of 48 and 72 h. These results indicate that Fuscus grow faster than Pelvetia and that the growth response of germlings to temporary emersion stress is more sensitive in Fucus than that in Pelvetia. Growth of germlings of both species was reduced with increasing density under favorable growth conditions (submerged control and 6 h / 12 h exposure treatments) in the periodic air-exposed experiments using tidal tanks, but was enhanced under severe emersion stress conditions. P. canaliculata showed better growth at 6 h exposure treatment than that of the control, under continuous submergence, indicating that Pelvetia germlings require a periodic exposure period. Fucus germlings always grew faster than those of Pelvetia and did best in mixed cultures, whereas Pelvetia did least well when mixed with Fucus germlings. The adverse effects of F. spiralis on P. canaliculata were greater than those of Pelvetia cohorts. The outcome of interspecific competi tion between F. spiralis and P. canaliculata gemlings was slightly altered by exposure period but not to such an extent as to change the outcome.

The antioxidant potential of methanolic extracts of brown seaweeds was assessed by Total Phenol Content, Ferric Reducing Antioxidant Power (FRAP), β-carotene bleaching and the DPPH scavenging assays. Ascophyllum nodosum, Pelvetia canaliculata, and Fucus serratus contained the highest phenol concentrations while Fucus vesiculosus and F. serratus exhibited the highest FRAP activities. F. vesiculosus and A. nodosum were the most effective extracts at scavenging DPPH radicals and preventing β-carotene bleaching. The antioxidant activity of the seaweed extracts was also evaluated in Caco-2 cells. All extracts significantly (P

International audience; The brown seaweed Pelvetia canaliculata and the marine angiosperm Salicornia ramosissima (purple glasswort) are two marine macrophytes growing in the upper intertidal zone. This location implies long emersion periods that lead to a direct exposure to UV solar radiation and to a potential photooxidative stress involving photoprotective compounds, such as phenols and pigments. To investigate the photoprotective responses in both species, which live under the same natural conditions but grow on different substrates, an experimental co-culture system was developed. Then, two three-week independent experiments were carried out with the artificial exposure of both macrophytes to a PAR alone treatment and either a PAR + dominant UV-A treatment (PA) simulating natural sunlight or a PAR + dominant UV-B treatment (PB) corresponding to high doses of UV-B radiations to enhance metabolic responses. Chlorophyll, carotenoid and phenol contents, as well as antioxidant activity, were determined for both species as a function of each light condition and exposure time (0, 7, 14 and 21 d). The accuracy and reproducibility of the first co-culture system created for both seaweeds and halophytes was confirmed by almost similar evolutions of pigments, phenols and antioxidant status after seven days of both PAR experiments. However, it seemed that young, annual and fast-growing plants of Salicornia ramosissima obtained from seed cultures acclimated slowly related to aging, perennial and apparently slow reacting thalli of P. canaliculata harvested in the field. Results showed that both UV treatments have almost no effect on chlorophyll contents. Carotenoid and phenol levels, as well as antioxidant activity, seemed to be less affected under PA treatment for both species. High doses of UV-B radiations induced few changes in carotenoid contents for both species, suggesting efficient constitutive contents for photoprotection. In contrast, phenol contents and antioxidant activity were not affected in P. canaliculata, whereas they decreased gradually in S. ramosissima. This could be explained by a fast acclimation of P. canaliculata to high UV-B radiations based on efficient contents of both phenols and carotenoids related to a strong antioxidant protection, versus a slow acclimation of S. ramosissima with a putative down regulation of phenols and the preferential involvement of carotenoids and/or other photoprotective systems.

Ca-loaded Pelvetia canaliculata biomass was used to remove Pb(2+) in aqueous solution from batch and continuous systems. The physicochemical characterization of algae Pelvetia particles by potentiometric titration and FTIR analysis has shown a gel structure with two major binding groups - carboxylic (2.8 mmol g(-1)) and hydroxyl (0.8 mmol g(-1)), with an affinity constant distribution for hydrogen ions well described by a Quasi-Gaussian distribution. Equilibrium adsorption (pH 3 and 5) and desorption (eluents: HNO(3) and CaCl(2)) experiments were performed, showing that the biosorption mechanism was attributed to ion exchange among calcium, lead and hydrogen ions with stoichiometry 1:1 (Ca:Pb) and 1:2 (Ca:H and Pb:H). The uptake capacity of lead ions decreased with pH, suggesting that there is a competition between H(+) and Pb(2+) for the same binding sites. A mass action law for the ternary mixture was able to predict the equilibrium data, with the selectivity constants alpha(Ca)(H)=9+/-1 and alpha(Ca)(Pb)=44+/-5, revealing a higher affinity of the biomass towards lead ions. Adsorption (initial solution pH 4.5 and 2.5) and desorption (0.3M HNO(3)) kinetics were performed in batch and continuous systems. A mass transfer model using the Nernst-Planck approximation for the ionic flux of each counter-ion was used for the prediction of the ions profiles in batch systems and packed bed columns. The intraparticle effective diffusion constants were determined as 3.73x10(-7)cm(2)s(-1) for H(+), 7.56x10(-8)cm(2)s(-1) for Pb(2+) and 6.37x10(-8)cm(2)s(-1) for Ca(2+).

The brown algae, or phaeophytes, are a large group of multicellular algae, including many notable types of seaweed. We analysed intra- and interspecific phylogenic studies within the genus Pelvetia in Korea and compared them with results of both same and different species in GenBank. The sequences for P. babingtonii in Korea were generally similar to those for P. babingtonii AF102957, and the sequences of P. siliquosa in Korea were also similar to those of P. siliquosa AF102958. Sequence variation within the Pelvetia is mostly due to nucleotide substitutions, although several small indels and some large indels can be found. Another source of sequence divergence is length variation due to stretches of short repeats that occur at the ITS1 or ITS2 in all the Pelvetia. NJ analysis consists mainly of two clades. One of them contains P. canaliculata and P. limitata, and is sister to the rest of the genus (P. siliquosa, P. compressa, and P. babingtonii). P. babingtonii is not grouped one clade. In the MP analysis, ten accessions or populations were fully resolved and all accessions from the same species formed with 99% or 100% bootstrap supports.

The daily variations of phenol contents and antioxidant capacities were surveyed in a 32-h field experiment in three temperate brown seaweeds belonging to Fucales – Pelvetia canaliculata , Ascophyllum nodosum and Bifurcaria bifurcata – living at different intertidal levels — high-, mid- and low-tide level, respectively. Phenolic compounds of brown seaweeds are secondary metabolites involved in many different protection mechanisms, as for example against grazer and pathogen attack as well as UV damage. This study was thus aimed at understanding the influence of both day/night and tidal cycles on the brown seaweed phenol pool with respect to their bathymetric level on the shore. These cycles affect the quantity and quality of light received by intertidal seaweeds (protection via the water layer during immersion), and the photoprotective role of phlorotannins was thus evaluated. Phenol levels and antioxidant capacities were monitored every hour during a tidal cycle and a half at the equinox spring tide, in March 2003. The three species contained rather high phenol levels, i.e. about 3, 6 and 4% DW in P. canaliculata , A. nodosum and B. bifurcata , respectively. Antioxidant capacities globally paralleled phenol contents in the three species under study. Moreover, the measured antioxidant capacities and the phenol contents of the extracts were significantly and positively correlated in the three species. Significant effect of neither cycles nor their interaction was observed in any species despite a trend to follow day/night alternation for P. canaliculata , and emersion/immersion cycle for A. nodosum . No trend was observed for the third species. However, significant correlations between phenol levels of P. canaliculata and A. nodosum and measured air-temperature were found. Our results suggested an effect of aerial, aquatic and both conditions on the phenolic pool of P. canaliculata , B. bifurcata and A. nodosum , respectively, and a fast evolution of the phenolic pool on a day time scale.

International audience; The photosynthetic activity and productivity of four dominant canopy intertidal macroalgae were measured under emersion and immersion, at saturating light levels (PAR > 300 μmol photons m−2 s−1), and compared at two sites (eastern and western English Channel) in spring and summer. The photosynthetic activity of thalli was measured by the electron transport rate (ETR) using pulse-amplitude modulated (PAM) fluorescence and the productivity of individuals and of communities was measured by carbon fluxes in closed chambers. Under emersion, when thalli were still hydrated, the uppermost species Pelvetia canaliculata had higher photosynthetic activity (mean ETR between 327 and 460 μmol e− m−2 s−1) and individual gross productivity (between 60 and 212 μmol C gDW−1 h−1) than the lowermost species Laminaria digitata (mean ETR between 24 and 53 μmol e− m−2 s−1 and gross productivity between 2 and 38 μmol C gDW−1 h−1), whatever the site and season. P. canaliculata had higher ETR in air than underwater (averaged 146 μmol e− m−2 s−1) and L. digitata had lower ETR in air than underwater (averaged 112 μmol e− m−2 s−1), while they exhibited respectively 3 and 5 times higher gross productivity underwater. At the community scale, the low mid-shore zone of Fucus serratus had the highest mean gross productivity under emersion (47 mmol C m−2 h−1) while rates were higher for the uppermost than lowermost zone at the eastern site (average 20 and 6 mmol C m−2 h−1 respectively) and of the same order of magnitude for both zones at the western site (about 30 mmol C m−2 h−1). Finally, the variability of under emersion primary productivity among sites and seasons was reduced when the measurements were performed on entire communities compared to isolated individuals of the dominant species.

The aim of this study was to investigate the cation exchange capacity of the macroalga Pelvetia canaliculata (Linnaeus) Decaisne & Thuret in a multi-metal system containing Cd2+, Pb2+, Cu2+ and Zn2+. The Na-loaded alga was established as a cation exchanger, in which cadmium, lead, copper, zinc and hydrogen ions present in the liquid phase exchange with sodium ions bound to the functional groups on the algal surface, mainly weakly acidic carboxylic groups and strongly acidic sulfonic groups. A mass action law for the senary system (Na+/H+/Cd2+/Pb2+/Cu2+/Zn2+) was able to predict the equilibrium data using the selectivity coefficients determined for the single-metal systems. Multi-metal equilibrium results, in agreement with the selectivity coefficients, showed a higher preference (affinity) of the biomass toward lead ions followed by copper, cadmium and zinc ions. A mass transfer model, considering equilibrium given by the mass action law, and a linear driving force model for intraparticle diffusion, was able to fit well the batch kinetic experimental data for all chemical species in the liquid and solid phase. The results indicate that the biomass of P. canaliculata is an efficient natural cation exchanger for multi-metal systems.

In this study, we investigated the effects of water-soluble extracts (WSE) from seaweed species Ulva rigida C. Agardh, Enteromorpha sp., Codium tomentosum (Huds) Stackh., Fucus vesiculosus L., Pelvetia canaliculata (L.) Decne et Thur, Dictyota dichotoma (Huds) Lamour, Chondrus crispus Stackh and Porphyra umbilicalis (L.) J. Agardh, on the respiratory burst of turbot phagocytes, in search of biologically active substances with immunostimulating capacities. The stimulatory capacities of the extracts varied greatly, depending on their origin, the concentrations used and the time of incubation. The best responses were induced by the extracts obtained from U. rigida , Enteromorpha sp. and C. crispus . Pre-incubation of the phagocyte cells with U. rigida and C. crispus extracts and subsequent incubation with phorbol myristate acetate (PMA) showed that these cells responded to further stimulation by this substance and, at some concentrations, they showed higher respiratory burst activity than control cells stimulated by PMA alone, suggesting that the extracts had a priming effect. We also tested the effects of protein-free water-soluble extracts (PF-WSE) and of the polysaccharide fractions (PSF) obtained from the PF-WSE of U. rigida and C. crispus . These extracts induced an increase in the respiratory burst activity of turbot phagocytes, suggesting that most of the stimulatory capacity of the water-soluble extracts was associated with polysaccharides.

Previous work has shown that distinct Ca(2+) gradients precede and predict the loci of germination of the zygotes of the brown alga, Silvetia compressa (J. Agardh) E. Serrão, T.O. Cho, S.M. Boo et Brawley, that are polarized by unilateral blue light. We show here that dark-grown S. compressa zygotes also form cytosolic Ca(2+) gradients prior to germination and then germinate from the site of elevated Ca(2+). In no case did germination occur without a prior formation of a Ca(2+) gradient. Using the self-referencing Ca(2+)-selective probe, we measured highly localized influx of Ca(2+) during photopolarization, indicating that extracellular stores supply at least some of the Ca(2+) needed to construct a gradient. Finally, we find that germination was inhibited by a bath-applied inhibitor of calcium/calmodulin-dependent kinase II (CaM kinase II), KN-93 (but not by its inactive analog, KN-92), and by an injected inhibitory peptide for the kinase. KN-93 did not interfere with the photopolarization of the zygotes, consistent with the view that calmodulin is not involved in the initial response to light. The KN-93 results indicate that the requirement for active CaM kinase II for germination ends about 2 h before overt germination. We conclude that Ca(2+) gradients, generated in part by localized calcium entry from the seawater, are an essential part of the process of polarity development and expression in these cells, regardless of the nature of the external cue that directs the orientation of the axis. Calmodulin and CaM kinase II are involved in interpreting (but not in establishing) the calcium gradient, allowing germination to occur at the site of elevated calcium, but CaM kinase II appears not to be involved in the initiation of germination.