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Fucales are an order within the Phaeophyceae that include most of the common littoral seaweeds in temperate and subtropical coastal regions. Many species of this order have long been a part of human culture with applications as food, feedand remedies in folk medicine. Apart from their high nutritional value, these seaweeds are also a well-known reservoir of multiple bioactive compounds with great industrial interest. Among them, phlorotannins, a unique and diverse class of brown algae-exclusive phenolics, have gathered much attention during the last few years due to their numerous potential health benefits. However, due to their complex structural features, combined with the scarcity of standards, it poses a great challenge to the identification and characterization of these compounds, at least with the technology currently available. Nevertheless, much effort has been taken towards the elucidation of the structural features of phlorotannins, which have resulted in relevant insights into the chemistry of these compounds. In this context, this review addresses the major contributions and technological advances in the field of phlorotannins extraction and characterization, with a particular focus on Fucales. [ABSTRACT FROM AUTHOR]

BackgroundMolecular markers are revealing a much more diverse and evolutionarily complex picture of marine biodiversity than previously anticipated. Cryptic and/or endemic marine species are continually being found throughout the world oceans, predominantly in inconspicuous tropical groups but also in larger, canopy-forming taxa from well studied temperate regions. Interspecific hybridization has also been found to be prevalent in many marine groups, for instance within dense congeneric assemblages, with introgressive gene-flow being the most common outcome. Here, using a congeneric phylogeographic approach, we investigated two monotypic and geographically complementary sister genera of north-east Pacific intertidal seaweeds (Hesperophycus and Pelvetiopsis), for which preliminary molecular tests revealed unexpected conflicts consistent with unrecognized cryptic diversity and hybridization.ResultsThe three recovered mtDNA clades did not match a priori species delimitations. H. californicus was congruent, whereas widespread P. limitata encompassed two additional narrow-endemic species from California - P. arborescens (here genetically confirmed) and P. hybrida sp. nov. The congruence between the genotypic clusters and the mtDNA clades was absolute. Fixed heterozygosity was apparent in a high proportion of loci in P. limitata and P. hybrida, with genetic analyses showing that the latter was composed of both H. californicus and P. arborescens genomes. All four inferred species could be distinguished based on their general morphology.ConclusionsThis study confirmed additional diversity and reticulation within NE Pacific Hesperophycus/Pelvetiopsis, including the validity of the much endangered, modern climatic relict P. arborescens, and the identification of a new, stable allopolyploid species (P. hybrida) with clearly discernable ancestry (♀ H. californicus x ♂ P. arborescens), morphology, and geographical distribution. Allopolyploid speciation is otherwise completely unknown in brown seaweeds, and its unique occurrence within this genus (P. limitata possibly representing a second example) remains enigmatic. The taxonomic separation of Hesperophycus and Pelvetiopsis is not supported and the genera should be synonymized; we retain only the latter. The transitional coastline between Point Conception and Monterey Bay represented a diversity hotspot for the genus and the likely sites of extraordinary evolutionary events of allopolyploid speciation at sympatric range contact zones. This study pinpoints how much diversity (and evolutionary processes) potentially remains undiscovered even on a conspicuous seaweed genus from the well-studied Californian intertidal shores let alone in other, less studied marine groups and regions/depths.

Fucales are an order within the Phaeophyceae that include most of the common littoral seaweeds in temperate and subtropical coastal regions. Many species of this order have long been a part of human culture with applications as food, feedand remedies in folk medicine. Apart from their high nutritional value, these seaweeds are also a well-known reservoir of multiple bioactive compounds with great industrial interest. Among them, phlorotannins, a unique and diverse class of brown algae-exclusive phenolics, have gathered much attention during the last few years due to their numerous potential health benefits. However, due to their complex structural features, combined with the scarcity of standards, it poses a great challenge to the identification and characterization of these compounds, at least with the technology currently available. Nevertheless, much effort has been taken towards the elucidation of the structural features of phlorotannins, which have resulted in relevant insights into the chemistry of these compounds. In this context, this review addresses the major contributions and technological advances in the field of phlorotannins extraction and characterization, with a particular focus on Fucales.

Fucus radicans is an endemic habitat-forming brown macroalga in the Baltic Sea that commonly complements its sexual reproduction with asexual reproduction. Asexual reproduction in F. radicans takes place through formation of adventitious branches (hereafter fragments), but the exact mechanisms behind it remain unknown. We assessed experimentally the importance of two environmental factors determining the re-attachment success of F. radicans fragments. By combining different light conditions (daylength and irradiance; high or low light) and water temperature (+14°C and +4°C), we mimicked ambient light and temperature conditions of winter, spring/autumn and summer for F. radicans. Fragments were able to re-attach in all tested conditions. Temperature and light had an interactive impact on re-attachment: the combination of high temperature and high light level resulted in the highest re-attachment success, while light level had no effects on re-attachment success in cooler water temperature and the re-attachment success in high temperature under low light levels was very low. The results suggest that rhizoid formation, and thus re-attachment success, may depend on the net primary production (metabolic balance) of the fragment. However, whether the re-attachment and asexual reproduction success simply depends on photosynthetic capacity warrants further mechanistic studies. Understanding the mechanisms of asexual reproduction in F. radicans is important in order to assess the dispersal capacity of this foundation species. [ABSTRACT FROM AUTHOR]

Enzymatic depolymerization of fucoidans attracts many researchers due to the opportunity of obtaining standardized fucoidan fragments. Fucoidanase catalyzes the cleavage of fucoidan from Fucus evanescens (FeF) to form low molecular weight products (LMP) and a polymeric fraction (HMP) with 50.8 kDa molecular weight and more than 50% yield. NMR spectroscopy shows that the HMP fraction has regular structure and consists of a repeating fragment [→3)-α- l -Fuc p 2,4OSO 3 − -(1 → 4)-α- l -Fuc p 2,4 O SO 3 − -(1 → 4)-α- l -Fuc p 2OSO 3 − -(1→] n . The anticancer effects of FeF fucoidan and its derivative (HMP) were studied in vitro on colon cancer cells HCT-116, HT-29, and DLD-1. The anticancer activity of the HMP fraction was found to be slightly lower than that of the FeF fucoidan. Research and practical applications of the enzyme include modification of native fucoidans for purposes of regular and easier characterized derivatives acquisition. [ABSTRACT FROM AUTHOR]

Cystoseira (Sargassaceae) is a genus of marine brown algae composed of about 40 species, which is distributed along the Eastern Atlantic and Mediterranean coasts. The biological potential of the Cystoseira genus has been investigated and several activities have been reported. Chemically, this genus contains a wide variety of secondary metabolites, such as terpenoids, steroids, phlorotannins and phenolic compounds. Additionally, other chemical components as, for instance, carbohydrates, triacylglycerols/fatty acids, pigments as well as vitamins have been identified in the studied species. Some of the isolated compounds were associated with the reported pharmacological properties, as for example antioxidant, anti-inflammatory, cytotoxicity, anticancer, cholinesterase inhibition, anti-diabetic, activities but also antibacterial, antifungal and anti-parasitic activities. In this review, we provide a comprehensive overview of the compounds isolated and identified after 1995 from the different species of Cystoseira , compiling more than 200 compounds isolated, together with their therapeutic potential. [ABSTRACT FROM AUTHOR]

Ocean warming and acidification may substantially affect the reproduction of keystone species such as Fucus vesiculosus (Phaeophyceae). In four consecutive benthic mesocosm experiments, we compared the reproductive biology and quantified the temporal development of Baltic Sea Fucus fertility under the single and combined impact of elevated seawater temperature and pCO2 (1100 ppm). In an additional experiment, we investigated the impact of temperature (0-25°C) on the maturation of North Sea F. vesiculosus receptacles. A marked seasonal reproductive cycle of F. vesiculosus became apparent in the course of 1 year. The first appearance of receptacles on vegetative apices and the further development of immature receptacles of F. vesiculosus in autumn were unaffected by warming or elevated pCO2. During winter, elevated pCO2 in both ambient and warmed temperatures increased the proportion of mature receptacles significantly. In spring, warming and, to a lesser extent, elevated pCO2 accelerated the maturation of receptacles and advanced the release of gametes by up to 2 weeks. Likewise, in the laboratory, maturation and gamete release were accelerated at 15-25°C relative to colder temperatures. In summary, elevated pCO2 and/or warming do not influence receptacle appearance in autumn, but do accelerate the maturation process during spring, resulting in earlier gamete release. Temperature and, to a much lesser extent, pCO2 affect the temporal development of Fucus fertility. Thus, rising temperatures will mainly shift or disturb the phenology of F. vesiculosus in spring and summer, which may alter and/or hamper its ecological functions in shallow coastal ecosystems of the Baltic Sea. [ABSTRACT FROM AUTHOR]

Fucaceae is the most dominant algae family along the intertidal areas of the Northern Hemisphere shorelines, being part of human customs for centuries with applications as a food source either for humans or animals, in agriculture and as remedies in folk medicine. These macroalgae are endowed with several phytochemicals of great industrial interest from which phlorotannins, a class of marine-exclusive polyphenols, have gathered much attention during the last few years due to their numerous possible therapeutic properties. These compounds are very abundant in brown seaweeds such as Fucaceae and have been demonstrated to possess numerous health-promoting properties, including antioxidant effects through scavenging of reactive oxygen species (ROS) or enhancement of intracellular antioxidant defenses, antidiabetic properties through their acarbose-like activity, stimulation of adipocytes glucose uptake and protection of β-pancreatic cells against high-glucose oxidative stress; anti-inflammatory effects through inhibition of several pro-inflammatory mediators; antitumor properties by activation of apoptosis on cancerous cells and metastasis inhibition, among others. These multiple health properties render phlorotannins great potential for application in numerous therapeutical approaches. This review addresses the major contribution of phlototannins for the biological effects that have been described for seaweeds from Fucaceae. In addition, the bioavailability of this group of phenolic compounds is discussed. [ABSTRACT FROM AUTHOR]

Main conclusion: Land plant cell wall glycan epitopes are present in Fucus vesiculosus. RG-I/AG mAbs recognize distinct glycan epitopes in structurally different galactans, and 3-linked glucans are also present in the cell walls. Cell wall-directed monoclonal antibodies (mAbs) have given increased knowledge of fundamental land plant processes but are not extensively used to study seaweeds. We profiled the brown seaweed Fucus vesiculosus glycome employing 155 mAbs that recognize predominantly vascular plant cell wall glycan components. The resulting profile was used to inform in situ labeling studies. Several of the mAbs recognized and bound to epitopes present in different thallus parts of Fucus vesiculosus. Antibodies recognizing arabinogalactan epitopes were divided into four groups based on their immunolocalization patterns. Group 1 bound to the stipe, blade, and receptacles. Group 2 bound to the antheridia, oogonia and paraphyses. Group 3 recognized antheridia cell walls and Group 4 localized on the antheridia inner wall and oogonia mesochite. This study reveals that epitopes present in vascular plant cell walls are also present in brown seaweeds. Furthermore, the diverse in situ localization patterns of the RG-I/AG clade mAbs suggest that these mAbs likely detect distinct epitopes present in structurally different galactans. In addition, 3-linked glucans were also detected throughout the cell walls of the algal tissues, using the β-glucan-directed LAMP mAb. Our results give insights into cell wall evolution, and diversify the available tools for the study of brown seaweed cell walls. [ABSTRACT FROM AUTHOR]

Mussel beds and rockweed stands (fucoid algae) have been shown to be alternative states on rocky intertidal shores in New England, and here the hypothesis that variation in recruitment provides opportunity for the development of alternative community states was tested. Disturbance by ice scour opens patches for development of alternative states, and in winter 1996-1997, 60 experimental clearings of differing sizes were established on Swan's Island, Maine, USA. Half of the plots were re-cleared during the winter of 2010-2011. Recruitment data for barnacles, mussels, and fucoid algae collected from 1997 to 2012 were used to (1) test for persistence of scale-dependent thresholds, (2) estimate the magnitudes and sources of variation, (3) fit a surface of alternative states as defined by the cusp catastrophe, and (4) test if 1997 recruitment would predict 2010-2011 recruitment in re-scraped plots (i.e., a test of divergence, which is expected in systems with alternative states). For barnacles and mussels, recruitment varied enormously year to year and among sites, but showed consistent patterns over the long-term with respect to clearing size. Average recruitment prior to re-clearing was a good predictor of recruitment afterwards. In contrast, over 50% of the variance in fucoid recruitment was unexplained with weak effects among years and locations. Past fucoid recruitment was a poor predictor of subsequent recruitment. The cusp analysis indicated that fucoid recruitment defines the alternative states. Fucoid recruitment was largely unpredictable and suggests long-term, small-scale priority effects drive the development of alternative states. These observations strongly reinforce the notion that long-term and well-replicated experiments are necessary to develop robust tests of ecological theory. [ABSTRACT FROM AUTHOR]

In dioecious species with both sexual and asexual reproduction, the spatial distribution of individual clones affects the potential for sexual reproduction and local adaptation. The seaweed Fucus radicans, endemic to the Baltic Sea, has separate sexes, but new attached thalli may also form asexually. We mapped the spatial distribution of clones (multilocus genotypes, MLGs) over macrogeographic (>500 km) and microgeographic (<100 m) scales in the Baltic Sea to assess the relationship between clonal spatial structure, sexual recruitment, and the potential for natural selection. Sexual recruitment was predominant in some areas, while in others asexual recruitment dominated. Where clones of both sexes were locally intermingled, sexual recruitment was nevertheless low. In some highly clonal populations, the sex ratio was strongly skewed due to dominance of one or a few clones of the same sex. The two largest clones (one female and one male) were distributed over 100-550 km of coast and accompanied by small and local MLGs formed by somatic mutations and differing by 1-2 mutations from the large clones. Rare sexual events, occasional long-distance migration, and somatic mutations contribute new genotypic variation potentially available to natural selection. However, dominance of a few very large (and presumably old) clones over extensive spatial and temporal scales suggested that either these have superior traits or natural selection has only been marginally involved in the structuring of genotypes. [ABSTRACT FROM AUTHOR]

Chromatographic fractionation of the organic extract obtained from the brown alga Cystoseira trinodis led to the isolation of a known carotene pigment ( 7), five C-29 steroids ( 2-6), including two new ones ( 2 and 5), and an unexpected metabolite, halogenated cyclic ene-yne ether ( 1). Compound 1 was isolated from the genus Cystoseira for the first time. This finding plays an important role in the chemo-taxonomical differentiation of C. trinodis from other Cystoseira species. All compounds ( 1-7) were evaluated for their in vitro cytotoxic activities against four human tumor cell lines MCF-7, HepG2, WI 38, and Vero. They showed moderate cytotoxicity with IC in the range 7-33 μM, where 7 exhibited the highest antioxidant activity with 72.1% inhibition. [ABSTRACT FROM AUTHOR]

Changes to associated communities when habitat is altered have been well documented in terrestrial and marine systems. In marine ecosystems, subtidal canopy removal of overlying vegetation is known to impact both physical and biological processes below. Recently, in Maine (USA), there has been much concern about the impact of harvesting (i.e., canopy removal) of Ascophyllum nodosum (rockweed) on the intertidal community. To examine the impacts of rockweed harvesting on the sediment structure and invertebrates associated with the sediment, control and experimentally harvested plots were established in May 2011 at Sears Island (Maine, USA). Monthly data collection through the summer and early fall included sediment cores, sieved infauna samples, and mobile megafauna quadrats. Sediment samples were analyzed for organic content as well as percent coarse sand, fine sand, silt, and clay. The experiment was repeated in 2012 in the same location with a modified design. In 2013 a commercially harvested site was sampled in the same manner before and after harvesting. Although differences in abundances of mobile megafauna were evident in the experimentally harvested sites, they were not evident in the commercially harvested site. Sediments and smaller invertebrates were mostly unaffected by canopy removal in both the experimentally and commercially harvested sites. While these data are contrary to those for subtidal canopy removal experiments, the rocky intertidal is a more physically dynamic habitat that may be tolerant of greater disturbance. [ABSTRACT FROM AUTHOR]

Highlights: [•] Marine macroalgae Pelvetia canaliculata showed to be a natural cation exchanger. [•] Sequestration of Zn2+ and Cu2+ by raw biomass occurs by the release of light metals. [•] The amount of weak acid carboxylic groups on the biomaterial surface is 1.5mEq/g. [•] The amount of strong acid sulfonic groups on the biomaterial surface is 1.0mEq/g. [•] Selectivity coefficients of the natural exchanger increases as Na+

In low-energy salt-marsh environments, Fucus spp. frequently exhibit an atypical morphology that is characterized by the absence of an anchoring holdfast and a trend towards reduced size and buoyancy, enhanced vegetative proliferation, and often the loss of sexual reproduction. Such forms, often referred to as ecads, presumably derive from typical attached forms, but their affinities are normally difficult to establish with confidence due to their simplified and largely convergent morphology. Minute salt-marsh forms growing partially embedded in the sediment occur on Atlantic and Pacific coasts and have traditionally been recognized as an independent entity, Fucus cottonii. In this study we analyse with four microsatellite loci two F. cottonii populations from salt-marshes of Oregon (NE Pacific) and Ireland (Europe, near the species type locality), as well as local populations of other Fucus spp. that could be considered potential source populations, either directly or via hybridization. Our results show that the F. cottonii from Oregon derive from F. gardneri whereas the Irish population is closer to F. spiralis. We conclude that F. cottonii is not a coherent genetic entity, but an artificial grouping of evolutionarily independent populations that converged into similar morphologies in different salt-marsh habitats. [ABSTRACT FROM PUBLISHER]

Abstract: Rapid mass spectrometric investigation of oligosaccharides, obtained by autohydrolysis of fucoidans from brown algae Silvetia babingtonii and Fucus evanescens (Fucales, Phaeophyceae) has shown both similarities and differences in structural features/sulfation pattern of their fragments, obtained in the same conditions. Tandem MALDI-TOF MS of fucooligosaccharides with even DP (degree of polymerization) was close to that observed for fucoidan from F. evanescens. Slight differences in tandem mass spectra of fragments with odd DP indicated, probably, sulfation at C-3 (instead of C-2 in F. evanescens) of some (1→4)-linked α-l-Fucp residues and/or the presence of short blocks, built up of (1→3)-linked α-l-Fucp residues. [Copyright &y& Elsevier]

Ascophyllum nodosum is a brown seaweed that grows abundantly in the US Northeast coastal region. This study examined the seasonal variation of A. nodosum in phenolic contents and subsequent antioxidant, α-glucosidase and α-amylase inhibitory activities. A. nodosum was harvested monthly and extracted in hot water and the resulting extracts were spray-dried. The results indicate a clear seasonal variation in terms of phenolic content, with June and July being the highest (36.4 and 37 mg/g, respectively) and May the lowest (21.8 mg/g). The antioxidant activities, in terms of 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity, correlated with the phenolic contents observed (r = 0.81), with the month of July being the highest (58%) and April the lowest (26%). Similarly in terms of Trolox equivalent, July had the highest activity (15.53 μM) and April and May the lowest (8.40 and 8.27 μM, respectively). α-glucosidase inhibitory activity exhibited a pattern similar to the phenolic contents observed with July having the highest inhibitory activity (IC(70) 2.23 μg) and April the lowest (IC(70) 26.13 μg), resulting in an inverse correlation between IC(70) values and total phenolic content (r = -0.89). Such seasonal variation is believed to be caused by temperature-related stress considering that A. nodosum is a cold water species. [ABSTRACT FROM AUTHOR]

Pleistocene glacial oscillations and associated tectonic processes are believed to have influenced the historical abundances and distribution of organisms in the Asia Northwest Pacific (ANP). Accumulating evidence indicates that factors shaping tempospatial population dynamics and distribution patterns of marine taxa vary with biogeographical latitude, pelagic behaviour and oceanographic regimes. To detect what kinds of historical and contemporary factors affected genetic connectivity, phylogeographic profiles of littoral macroalga Sargassum horneri in the ANP were analysed based on mitochondrial (Cox3) and chloroplast ( rbcL) data sets. Five distinct clades were recovered. A strong signature of biogeographical structure was revealed (ΦCT = 0.487, P < 0.0001) derived from remarkable differentiation in clade distribution, as clade I is restricted to Chinese marginal seas (Yellow-Bohai Sea, East China Sea and South China Sea), whereas clades II-V are discontinuously scattered around the main Islands of Japan. Furthermore, two secondary contact regions were identified along the south Japan-Pacific coastline. This significant differentiation between the two basins may reflect historical glacial isolation in the northwestern Pacific, which is congruent with the estimates of clade divergence and demographic expansion during the late Quaternary low sea levels. Analysis of molecular variance and the population-pair statistic FST also revealed significant genetic structural differences between Chinese marginal seas and the Japanese basin. This exceptional phylogeographic architecture in S. horneri, initially shaped by historical geographic isolation during the late Pleistocene ice age and physical biogeographical barriers, can be complicated by oceanographic regimes (ocean surface currents) and relocating behaviour such as oceanic drifting. [ABSTRACT FROM AUTHOR]

This study investigated the antibacterial activity of glycolipid-rich extracts of the brown macroalga in cell culture. Accessions were collected on the Arctic coast of Ungava Bay, Nunavik, Quebec. The crude ethyl acetate extract of these accessions showed strong antibacterial activity (≥4 log10 cfu) against , , (ATCC and clinical isolate), and at 100 µg/mL. This algal extract inhibited by 3 log10 and methicillin-resistant , whereas , , , and were not significantly affected. Further investigations of the activity of a glycolipid-rich fraction, extracted with dichloromethane, against Propionibacterium acnes showed an MIC100 of 50 µg/mL, with an inhibition of more than 99% at only 7.8 µg/mL. The main active compound, a β- d-galactosyl O-linked glycolipid, was synthesized for the bioassay and showed an MIC100 of 50 µg/mL but lost its activity more quickly with only 50% of inhibition at 12.5 µg/mL. Therefore, the semipurified F. evanescens extract could be a good choice for future research into the development of alternative treatments for acne therapy. [ABSTRACT FROM AUTHOR]

The article focuses on the multi gene phylogeny of the brown algal family Fucaceae. It states that this phylogeny reveals the relationships and recent drivers of a marine radiation. It mentions that diversification occurs in the Late-Mid Miocene with four independent tras-Arctic lineage crossings. It also mentions that the genus Fucus arises in the Piliocene because climatic factors promotes differentiation between two clades.

The article discusses a study on the effects of seabird nesting colonies on algae and aquatic invertebrates in surrounding coastal waters and marine communities. Fucus vesiculosus fronds were collected in the study, along with its epiphytic algae, associated invertebrate fauna near abandoned and active cormorant nesting islands as well as reference islands without nesting cormorants in the Stockholm archipelago in the northern Baltic Sea, Sweden. Stable isotope analyses showed that ornithogenic nitrogen provided a significant nitrogen source for algae and invertebrate consumers near islands with high nest density. The study concluded that runoff from seabird colonies affected primary producers and some consumers in the surrounding water if the colonies exceed a certain nest density.

In the Baltic Sea, the broadly distributed brown alga Fucus vesiculosus coexists in sympatry over part of its range (south west Gulf of Bothnia) with the Baltic endemic F. radicans sp. nov, while further north in colder and lower-salinity areas of the Baltic F. radicans occurs alone (north west Gulf of Bothnia). F. radicans appears to have arisen via rapid speciation from F. vesiculosus within the recent history of the Baltic (ca. 7500 BP). Possible functional divergence between the two species was investigated by comparing stress-responsive gene expression in a common-garden experiment. The experiment used two allopatric populations of Fucus vesiculosus from the Skagerrak (North Sea) and Central Baltic, as well as F. radicans from the same Central Baltic site. The two species in sympatry displayed divergent heat shock responses, while F. vesiculosus populations from allopatric sites did not. F. radicans was more sensitive to heat shock at 25°C, either alone or together with high irradiance and desiccation, than Baltic or Skagerrak F. vesiculosus. The results indicate that rapid functional divergence in the inducible heat shock response has occurred between sympatric species on a timescale of thousands of years. [ABSTRACT FROM AUTHOR]

Abstract: Within a project focusing on the chemopreventive potential of algal phenols, two phloroglucinol derivatives, belonging to the class of fucophlorethols, and the known fucotriphlorethol A were obtained from the ethanolic extract of the brown alga Fucus vesiculosus L. The compounds trifucodiphlorethol A and trifucotriphlorethol A are composed of six and seven units of phloroglucinol, respectively. The compounds were examined for their cancer chemopreventive potential, in comparison with the monomer phloroglucinol. Trifucodiphlorethol A, trifucotriphlorethol A as well as fucotriphlorethol A were identified as strong radical scavengers, with IC50 values for scavenging of 1,1-diphenyl-2 picrylhydrazyl radicals (DPPH) in the range of 10.0–14.4μg/ml. All three compounds potently scavenged peroxyl radicals in the oxygen radical absorbance capacity (ORAC) assay. In addition, the compounds were shown to inhibit cytochrome P450 1A activity with IC50 values in the range of 17.9–33μg/ml, and aromatase (Cyp19) activity with IC50 values in the range of 1.2–5.6μg/ml. [Copyright &y& Elsevier]

While the importance of canopy-forming algae in structuring ecosystems is recognized, their role in the carbon budget is still not well understood. To our knowledge, no measurements of rocky shores primary production and respiration under emersion periods have been carried out in situ. A benthic chamber coupled to a CO2-infrared gas analyzer was used to measure gross primary production and respiration on the Ascophyllum nodosum (L.) Le Jol. zone of a sheltered rocky shore in Brittany, France. Over a year of monthly measurements on the zone with and without the A. nodosum canopy showed fairly high production and respiration values for the global community as well as carbon fluxes due to the canopy that largely dominated the benthic metabolism of the zone. The strong canopy respiration relative to the primary production also suggested a high metabolic activity by microscopic heterotrophs on the surface of the alga. Both the canopy and the understory annual primary production and respiration were under the control of light and temperature seasonal variations. Finally, the range of the amount of carbon produced on the A. nodosum zone during diurnal emersions was estimated. Additional measures accounting for the day–night cycles and seasonal light variations over an entire tidal cycle are, however, necessary to establish an annual carbon budget. Such measures using the benthic chamber together with complementary techniques would allow a better understanding of the functioning of sheltered rocky shores. [ABSTRACT FROM AUTHOR]

Abstract  A site in the western part of Long Island Sound was monitored from January 2000 to May 2002. The littoral was divided into five different zones from the supra-littoral fringe (A) to the infra-littoral fringe (E). The midshore was dominated by Fucus vesiculosus L. and the sublittoral fringe by Chondrus crispus Stackh. There was a significant change in community structure over the years and the predominant change occurred between 2001 and 2002. The alternation in community structure was caused by an increase in abundance of species like Porphyra suborbiculata Kjellm., Porphyra leucosticta Type A and C (Neefus et al. 2000), Ceramium virgatum Roth, and Codium fragile subsp. tomentosoides (van Goor)Silva and a decrease in abundance in Fucus vesiculosus, Blidingia minima (Nägeli ex Kütz.) Kylin and Ulva lactuca L. The changes in community structure coincided with the change in environmental conditions. Air temperature as well as surface seawater temperature (depth [ABSTRACT FROM AUTHOR]

Comparative study of phytochemical compositions of the most widespread brown algae species (one laminarian and four fucoid algae) from Barents Sea has been performed. A modified technique for mannitol determination in brown algae is proposed. It was revealed that fucus algae (fam. Fucaceae) contain 3% (of total dry weight) less mannitol than laminaria ( Laminaria saccharina). The contents of alginic acid and laminaran in the Barents Sea fucoids are more than 10% less compared to laminaria. The alga L. saccharina contains almost two times more iodine than the species of fam. Fucaceae. The amounts of fucoidan and sum lipids in the Barents Sea fucoid algae is higher than in Laminaria saccharina (4–7% and 1–3%, respectively). In terms of contents of main biologically active compounds, fucus and laminarian algae from Barents Sea are inferior to none of the Far-Eastern species. The Barents Sea algae may become an important source of biologically active compounds. [ABSTRACT FROM AUTHOR]

The prevalence of antigrazing defense induction and the cues triggering induction in marine macroalgae are generally not well understood. We examined the capacity of defense and the mechanisms of regulation in five common perennial macroalgal species from the Baltic Sea, Furcellaria lumbricalis (Huds.) J. V. Lamour. , Delesseria sanguinea (Huds.) J. V. Lamour. , Phyllophora pseudoceranoides (S. G. Gmel.) Newroth et A. R. A. Taylor , Fucus serratus L., and Fucus evanescens C. Agardh. Specifically, we investigated whether direct feeding and/or waterborne cues from feeding on neighboring conspecifics decreased the palatability of the tested algae. Direct feeding by the local isopod Idotea baltica triggered the induction of chemical defense in Fur. lumbricalis, D. sanguinea, P. pseudoceranoides, F. serratus, and F. evanescens. Conversely, we did not find any evidence for waterborne cues associated with feeding to trigger defense induction in neighboring conspecifics. [ABSTRACT FROM AUTHOR]

The effect of fucoidan (1.3; 1.4-α-L-fucan), a sulfated polysaccharide from the brown alga Fucus evanescens on the formation of specific granular and tubular inclusions induced by tobacco mosaic virus (TMV) and consisted presumably of the virus-coded protein components of the viral replicase was investigated in the TMV-infected leaves of tobacco ( Nicotiana tabacum L.). In four days after inoculation of the leaves with a TMV preparation (1 mg/ml), the signature of infection in a presence of fucoidan (1 mg/ml) was a preferential formation of intracellular granular inclusions, which were related to early stages of the virus reproduction. When infected leaves were not treated with fucoidan, their cells contained mainly tubular inclusions, which were presumably formed from the granular ones on the last stages of the infection process. These observations demonstrated that fucoidan delayed the development of the TMV-induced infection. [ABSTRACT FROM AUTHOR]

Using optical and scanning electron microscopy the structure and development of the air bladders of Fucus vesiculosus and Ascophyllum nodosum are described in an ecological context from Nova Scotia. The air bladders consist of a bladder wall that surrounds an air space traversed by a complex network of white fibers. Microscopically, the fibers consist of branched, uniseriate filaments in which cells are uninucleate with a thin cytoplasmic region and thick cell walls. The filaments are formed from irregular sheets of cells consisting of a cluster of filaments surrounded by mucilaginous material. These become detached from the surrounding material as the bladder inflates. In very large bladders the filamentous network can be broken and leave a felt-like mat on the bladder wall. Bladders of F. vesiculosus have thinner walls than A. nodosum (300 μm vs 500 μm, respectively). In addition, successively older bladders in the former species become damaged and lose their structural integrity, whereas this does not occur in the latter species. After 10 years of age, almost 90% of bladders in A. nodosum are still intact with no change between year 1 and year 10. In the shorter-lived F. vesiculosus, more than 50% of the visible bladders have been damaged, and only one or two bladders remain intact near the apices of branches. We conclude that the bladders of A. nodosum are able to undergo repair when the bladder wall is punctured, whereas those of F. vesiculosus do not. [ABSTRACT FROM AUTHOR]

Pulse amplitude modulation (PAM) fluorometry was used in 2004 and 2005 to measure chlorophyll a fluorescence associated with photosystem II in eggs and embryos of Ascophyllum nodosum (Linnaeus) Le Jolis from the Atlantic coast of Nova Scotia. Fucoid eggs and embryos were maintained in the laboratory for 8 days over which fluorescence measurements were taken. Newly released eggs saturated at about 20 μmol photons m-2 s-1 with maximum electron transport rate (rETRmax) declining to <3 after 3 days. Embryos saturated at about 50 μmol photons m-2 s-1 and rETRmax increased to >11 by day 3. Although some egg senescence was apparent by day 3, some eggs continued to generate a strong photosynthetic signal throughout the 8-day experimental period, even though rETRmax was reduced. Differences in photosynthetic responses associated with fertilisation were apparent in Fv/Fm, within 24 h, and in rETRmax after 2 days. Eggs showed relatively stable or declining responses, whereas embryos showed stable or increasing responses. By day 8, quantum yield of embryos was similar to values reported elsewhere for mature fucoids. [ABSTRACT FROM AUTHOR]

The in situ grazing experiments were performed in the shallow water rocky habitat of the northern Baltic Sea during ice-free season 2002. In the experiments the effects of algal species and choice on the grazing of the mesoherbivores Idotea baltica (Pallas) and Gammarus oceanicus Segerstråle were tested. Salinity, temperature, concentration of nutrients in water and macroalgae and net production of macroalgae were considered as random effects in the analysis. The invertebrate feeding rate was mainly a function of the net photosynthetic activity of Pylaiella littoralis (L.) Kjellman and Fucus vesiculosus L. Feeding rate increased significantly with decreasing algal photosynthetic activity. When the two algal species were incubated together invertebrates fed primarily on P. littoralis. Low selectivity towards P. littoralis coincided with its high photosynthetic activity. The presence of F. vesiculosus did not modify the invertebrate feeding on P. littoralis. The results indicated that (1) the grazing on F. vesiculosus depended on the availability of P. littoralis, (2) the photosynthetic activity of algae explained the best the variation in grazing rate and (3) the grazers are not likely to control the early outbreak of filamentous algae in the northern Baltic Sea by avoiding young and photosynthetically active algae. The likely mechanism behind the relationship is that the increased photosynthetic activity of macroalgae coincides with their higher resistance to herbivory. [ABSTRACT FROM AUTHOR]

Brown seaweeds of the genus Fucus occupy a wide variety of temperate coastal habitats. The genus is evolutionary dynamic with recent radiations to form morphologically distinct taxa. In the brackish Baltic Sea, fucoids are the only perennial canopy-forming macroalgae. The most northern populations of Fucus occur permanently submerged in extremely low salinity (3–5 psu). These are currently referred to as Fucus vesiculosus L. but are morphologically distinct with a narrow frond without bladders. We report here that a population of this unique morphotype is reproductively isolated from a truly sympatric population of common F. vesiculosus and conclude that the northern morphotype represents a previously undescribed species. We describe Fucus radicans sp. nov., which is attached and dioecious with broadly elliptic receptacles, characterized by a richly branched narrow flat frond (2–5 mm), short thallus (<26 cm), and a high capacity for vegetative recruitment of attached plants. Analysis of five highly polymorphic microsatellite DNA loci showed genetic differentiation between sympatric populations of F. radicans and F. vesiculosus, whereas allopatric populations of the same species revealed a coherent pattern of genetic variation. Sequences of the RUBISCO region in F. radicans were identical to or differing at only one to two dinucleotide positions from those of F. vesiculosus, indicating a recent common origin of the two species. [ABSTRACT FROM AUTHOR]

Competitive interactions between germlings of Ascophyllum nodosum (L) Le Jolis and Fucus vesiculosus L. were studied both in the laboratory and on a shore of the Isle of Man, in the Irish Sea. Both intra- and interspecific competition were investigated by comparing the performance of algal germlings both in monocultures and mixed populations of the two species. The growth of germlings of both species reduced with increasing density. F. vesiculosus always grew faster than Ascophyllum and did best in mixed cultures, whereas Ascophyllum did least well when mixed with Fucus germlings. Clearly the adverse effects of F. vesiculosus on A. nodosum were greater than those of Ascophyllum cohorts. At the same total density, the survival and growth of Ascophyllum declined with an increasing proportion of Fucus germlings, implying that poor recruitment of A. nodosum results from strong competition with F. vesiculosus. However, under desiccation stress on the shore, F. vesiculosus enhanced the survival of A. nodosum at the early germling stage even though competition may occur again at the late stage. Thus, whether interactions between germlings take the form of competition or facilitation depends on the environmental conditions. [ABSTRACT FROM AUTHOR]

To date, molecular markers have not settled the question of the specific status of the closely related, but phylogenetically unresolved, brown seaweeds, hermaphroditicFucus spiralisand dioeciousFucus vesiculosus, nor their propensity for natural hybridization. To test the degree of species integrity and to assess effect of the mating system on the population genetic structure, 288 individuals coming from parapatric (discontinuous) and sympatric (contiguous) spatial configurations at two sites were genotyped with five microsatellite loci. Using a Bayesian admixture analysis, our results show thatF. spiralisandF. vesiculosuscomprise clearly distinct genetic entities (clusters) generally characterized by cosexual and unisexual individuals, respectively. Genetic diversity within each entity suggests thatF. spiralisreproduces primarily through selfing whileF. vesiculosusis characterized by an endogamous breeding regime. Nevertheless, aberrant sexual phenotypes were observed in each cluster, no diagnostic alleles were revealed and 10% of study individuals were intermediate between the two genetic entities. This pattern can be explained by recent divergence of two taxa with retention of ancestral polymorphism or asymmetrical, introgressive hybridization. However, given (i) coincident monomorphism at three loci inspiralisclusters and (ii) that significantly more intermediates were observed in sympatric stations than in parapatric stations, we argue that interspecific gene flow has occurred after divergence of the two taxa. Finally, we show that whether recently separated or recently introgressive, the divergent breeding systems probably contribute to species integrity in these two taxa. [ABSTRACT FROM AUTHOR]

Long-lived species of large size can play critical roles as ecosystem engineers but the demography of early life stages is poorly known for many such species. For example, the fucoid alga,Ascophyllum nodosum, serves as the foundation species for many sheltered rocky shore communities of the North Atlantic Ocean, yet its early demography is incompletely characterized. Here we provide data on age-specific survivorship throughout the first year. We outplanted zygotes generated from artificial fertilizations and followed their survivorship under different conditions that tested the following hypotheses: (1) survivorship is inversely related to clearing size, (2) germlings survive better in clearings in conspecific stands than in clearings in mussel beds, (3) survivorship in microhabitat refugia (grooves of artificial surfaces) is greater than that on flat surfaces, and (4) protection from grazing and physical factors, like canopy sweeping and desiccation, enhances germling survival. Germlings were censused on days 2, 9, 13, 17, 64, 102, 127 and 399 following outplanting. Germling mortality was consistently higher on flats than in grooves of artificial surfaces, and was greatest within the first two days of life. Germlings protected by cages survived better during the day 0–2 interval, but after 2 days caging did not matter. Interval-specific mortalities after day 2 showed that survivorship was inversely related to clearing size. The type of clearing, in conspecific stands or mussel beds, did not affect survivorship.Ascophyllum nodosumshows a strong type III survivorship curve with mortality during year 1 exceeding 99.9%. The poor survivorship of first year germlings accounts for the paucity of newly recruited juveniles often observed in mature stands ofA. nodosum. The lack of juveniles and the scale dependent survivorship of germlings renders populations ofA. nodosum, and the associated community that depends on it, vulnerable to large scale perturbations. [ABSTRACT FROM AUTHOR]