Quantitative studies on brown algal phenols. II. Seasonal variation in polyphenol content of Ascophyllum nodosum (L.) Le Jol. and Fucus vesiculosus (L.)

The content of extractable polyphenols in the brown algae Ascophyllum nodosum (L.) Le Jol. and Fucus vesiculosus (L.) was measured at ≈28-day intervals for one year. Colorimetric methods based on the Folin-Denis, Brentamine, and vanillin-H₂SO₄ reactions were used to estimate relative contents of polyphenols, and these values were converted to absolute contents using the gravimetric method introduced earlier. Relatively little error was introduced by variations in the qualitative composition of the extracted polyphloroglucinols.There appeared to be a significant temporal correlation between polyphenol content and the reproductive state of the algae. The content of polyphenols in A. nodosum was at a minimum (≈9–10% of dry matter) during the period of maximum fruit body shedding (late May), and reached a maximum (≈12–14% of dry matter) during the ‘winter season’. In F. vesiculosus, the minimum (≈8–10% of dry matter) was one to two months later, just before the period of maximum fertility, and thereafter rose to a maximum (≈11–13% of dry matter) during the period of sterility. These results furthermore suggest that the bulk of the polyphenols are not readily accessible as reserve components, and indicate that modifications may be needed in the ‘chemical defense’ and ‘waste product’ hypotheses concerning the significance of brown algal polyphenols.     

Biostimulant activity of brown seaweed species from Strangford Lough: compositional analyses of polysaccharides and bioassay of extracts using mung bean (Vigno mungo L.) and pak choi (Brassica rapa chinensis L.)

The aims of this study were to characterise the composition of seaweed species and to evaluate the efficacy of aqueous extracts as plant biostimulants. Five species (Ascophyllum nodosum, Fucus serratus, Fucus vesiculosus, Laminaria hyperborea and Sargassum muticum) of seaweed were harvested from Strangford Lough, Northern Ireland for the evaluation of polysaccharides, indole-3-acetic acid (IAA), carbon, nitrogen, lipid, ash and mineral contents. The compositional analyses of the five species and their freeze-dried extracts were also carried out using thermogravimetric analysis, scanning electron microscopy and X-ray microanalysis. The concentration of IAA in the acid extracts of the five species ranged between 2.74 and 46.8?ng?g^?1. The carbon, nitrogen, lipid and ash contents ranged between 25.0 and 38.6, 1.37%, and 3.16, 0.83%, and 3.98 and 18.10 and 47.68%, respectively. L. hyperborea and S. muticum contained the highest amounts of minerals. The biostimulant activities of acidic (pH?3.0), neutral (pH?6.5) and alkaline (pH?9.0) extracts were determined by mung bean bioassay. The alkaline extracts from F. vesiculosus and A. nodosum stimulated significantly (P?<?0.001) higher dry matter (DM, %) yield of the mung bean plants. The majority of the acidic extracts significantly (P?<?0.001) enhanced root formation on the mung bean stem cuttings compared to alkaline or neutral extracts. The acidic extracts of the five species, water control and a commercial product were evaluated as foliar feeds for pak choi plants using a hydroponic production system. The interaction of species, e.g. A. nodosum and F. vesiculosus and the two treatment dilutions on DM yield increases of pak choi were significant (P?<?0.05).     

SETTLEMENT AND SURVIVAL OF POLYSIPHONIA LANOSA (CERAMIALES) SPORES ON ASCOPHYLLUM NODOSUM AND FUCUS VESICULOSUS (FUCALES)1

The settlement patterns of spores of Polysiphonia lanosa (L.) Tandy on Ascophyllum nodosum (L.) Le Jolis and Fucus vesiculosus L. were studied using a flow tank. Settlement sites were defined as ‘sheltered’ or ‘exposed.’ Surface area calculations revealed non-random settlement on A. nodosum, with higher than expected spore frequencies on the thallus and lateral pits and lower than expected frequencies on the vesicles. Settlement of F. vesiculosus was random and significantly lower than on A. nodosum. On the shore, survival of sporelings from September (post-sporulation) to May (pre-sporulation) was highly non-random on both basiphytes. On A. nodosum, lateral pits ('sheltered') showed the highest survival frequency. Here the proportion of surviving sporelings increased over the study period, whereas the proportion on open thallus area ('exposed') decreased. On F. vesiculosus also preferential survival occurred on ‘sheltered’ sites such as vesicle/thallus interfaces and wounds. Between September and May, all P. lanosa sporelings were lost from ‘exposed’ areas (thallus surface and vesicles). Overall, frequencies of surviving sporelings were much greater on A. nodosum than on F. vesiculosus. These results are discussed with reference to basiphyte morphology, epiphyte removal mechanisms and the survival stratagy of P. lanosa.     

The effect of zinc on the increase in length of five species of intertidal fucales

The growth rate of Pelvetia canaliculata (L.) Dec. et Thur., Fucus spiralis L., F. vesiculosus L., F. serratus L., and Ascophyllum nodosum (L.) Le Jolis was measured in six different concentrations of zinc (0.025–14 mg/l) during a period of ten days. No significant growth response was observed at 0.1 mg/l of zinc. A significant reduction of growth during the first two to three days of exposure to 1.4 mg/l or more was followed by no or small further decline. Apices of A. nodosum from localities with different background load of zinc (0.1–0.5 mg/l and <0.01 mg/l) showed no difference in response to 2.6 mg/l of zinc.     

Distribution and radical scavenging activity of phenols in Ascophyllum nodosum (Phaeophyceae)

Phlorotannins have been purified and fractionated in the brown alga Ascophyllum nodosum using successively differential extraction, liquid-liquid separation and dialysis. Both the phenol content and the radical scavenging capacity of the resulting fractions were assayed by the Folin-Ciocalteu test and the DPPH method, respectively, whilst purity of the fractions was assessed by ¹H NMR analysis. The purification process resulted in the isolation of six fractions from each crude extract with only minor losses. High levels of phenols, up to 97-99%, were measured in semi-purified fractions containing phlorotannins more than 50 kDa in average molecular size, accounting for more than 95% of the ethyl acetate phenol pool. As a consequence, purity decreased in ethyl acetate fractions together with the molecular size of compounds. The importance of differential extraction based on the polarity of phenols is highlighted by the fact that most of these compounds were found in the ethyl acetate fraction after the first extraction step in 100% methanol, whilst two thirds of phenols extracted by 50% methanol remained in the aqueous phase. The radical scavenging activity of the fractions was correlated with the phenol content and was maximal in complete ethyl acetate fractions and in dialysis concentrates containing molecules more than 50 kDa in size. The specific activity of phenols was found to be maximal for molecules smaller than 2 kDa when isolated from the 100% methanol extract and 1-4 times smaller in the water phase separated from the same extract. The distribution of radical-scavenging potentials in the phenol pool of A. nodosum supports the idea that physiological roles and putative uses of phlorotannins are under the control of a polarity-molecular size complex.     

Quantitative studies on brown algal phenols. I. Estimation of absolute polyphenol content of Ascophyllum nodosum (L.) Le Jol. and Fucus vesiculosus (L.)

Methods for estimating the absolute polyphenol content of the brown algae Ascophyllum nodosum (L.) Le Jol. and Fucus vesiculosus (L.) have been developed and tested. Polyphenols were extracted almost quantitatively from Ascophyllum nodosum using aqueous acetone, whereas this procedure was somewhat less efficient with Fucus vesiculosus. Colorimetric methods based on the Folin-Denis reagent, Brentamine Fast Red 2G Salt, and vanillin-H₂SO₄ were applied to acetone-free extracts for determination of polyphenol content relative to suitable reference compounds. Gravimetric methods based on hide powder and on haemoglobin were employed to derive ‘estimation factors’ (EFs) which allow calculation of the absolute polyphenol content from the relative polyphenol content. The values calculated for absolute polyphenol content are considered to be reasonably accurate, despite imprecisions in the methods and despite often large standard deviations, and re-emphasize the potential physiological and ecological significance of brown algal polyphenols. Although the precise EFs calculated here are not valid for other brown algae, the methods are considered to be generally applicable to other Phaeophyceae.     

Systematic implications of the peroxidase isoenzymes in the Xanthium strumarium complexes

Starch-slab gel electrophoresis showed two patterns of peroxidase isoenzymes in the polymorphic taxon. Xanthium strumarium L. The “strumarium” morphological complex (X. strumarium, in the sense of Millspaugh and Sherff), the putative indigenous plants of the Old World, contained a different pattern from that shown by putative introductions from the New World. Experimental F₁ hybrids between “strumarium” and other complexes, “italicum-pennsylvanicum”, “chinense”, “oviforme” and “cavanillesii”, had the peroxidase pattern of the American plants. These peroxidase isoenzyme patterns were not influenced by the environmental growing conditions, but, along with partial genetic incompatibility, support the taxonomic separation of X. strumarium from other taxa of section Euxanthium.     

Floating seaweed and the influences of temperature, grazing and clump size on raft longevity — A microcosm study

Laboratory experiments were conducted to evaluate the longevity, and consequently also the rafting capacity of the brown seaweeds Fucus vesiculosus and Ascophyllum nodosum. The seaweed degradation process and the activity of the grazer Idotea baltica were strongly influenced by temperature: only at 5 °C, the seaweed growth exceeded the weight loss. At higher temperatures, seaweed fragments sank quickly (within 100 days at temperatures higher than 15 °C). This process was significantly accelerated in the presence of I. baltica, resulting in a decrease of raft longevity of 60-70%. At a constant temperature of 15 °C and in the absence of grazers, fragments of A. nodosum floated longer (mean 45 weeks) than fragments of F. vesiculosus (mean 15 weeks). The results indicate that floating seaweeds have the potential to stay afloat for a long time, but that their longevity is temperature-dependent and can be strongly reduced by grazing activity of associated herbivores.     

Separation and identification of lipids and fatty acids of the marine algaFucus vesiculosus by TLC and GC—MS

Ten fractions of polar and nonpolar lipids (phospholipids, glyeolipids and neutral lipids) were isolated from the brown marine algaFucus vesiculosus by TLC. In each fraction the quality and quantity of fatty acids were determined by GC—MS.F. vesiculosus is another type of marine alga suitable as a source of polyene fatty acids.     

Circular dichroism and absorption spectra of bacteriochlorophyll-protein and reaction center complexes from Chlorobium thiosulfatophilum

A water-soluble bacteriochlorophyll-protein and a complex which also contained photochemically-active reaction centers were isolated from Chlorobium thiosulfatophilum. The procedures were similar to those used previously on Chloropseudomonas ethylica (Fowler, C. F., Nugent, N. A. and Fuller, R. C. (1971) Proc. Natl. Acad. Sci. U.S. 68, 2278–2282), and the corresponding complexes from the two organisms exhibit marked similarities. They are characterized in terms of their absorption spectra at 100 and 300 °K, circular dichroism spectra at 300 °K, and, in the case of the reaction center complexes, by the light- or oxidation-induced changes in the absorption and circular dichroism spectra. On the basis of exciton interactions observed in the circular dichroism and low-temperature absorption spectra, we conclude that the predominant pigment arrangement in the bacteriochlorophyll-reaction center complex is distinctly different from that in the bacteriochlorophyll-protein.     

Fucus ‘lignin’: A reassessment

A ‘lignin’ fraction isolated by the Björkman method from the marine brown alga Fucus vesiculosus has been examined by ¹³C NMR and degradative analysis, and shown to consist of polyphloroglucinols identical to those characterized earlier from Fucus. No evidence for the presence of lignin in F. vesiculosus could be found.     

Characterization of microsatellite loci in the marine seaweed Ascophyllum nodosum (Phaeophyceae; Fucales)

Ascophyllum nodosum L. dominates rocky intertidal shores throughout the temperate North Atlantic. Six microsatellite loci were developed for A. nodosum using enriched libraries. The number of alleles ranged from 9 to 24 and heterozygosities from 0.2213 to 0.7785. Ascophyllum is monotypic. There was no cross‐reactivity observed with Fucus serratus, F. vesiculosus or F. evanescens.     

Lipid Metabolism in the Brown Marine Algae Fucus vesiculosus and Ascophyllum nodosum

Lipid metabolism and environmental effects on this process havebeen studied in the marine brown algae Fucus vesiculosus andAscophyllum nodosum. These algae showed very similar patternsof lipid metabolism during 24 h incubations. Labelling from[1-¹⁴C]acetate showed the major labelled lipids to be the ß-alanineether lipid and the neutral lipid fraction in both algae. Ofthe glycolipids, only sulphoquinovosyldiacylglycerol was welllabelled and the phosphoglycerides were all poorly labelled.The major labelled fatty acids were palmitate and oleate, againin both algae, although Fucus vesiculosus also showed significantlabelling of stearate and behenate. Although the amount of fattyacid labelling increased with time, the proportion of labelin palmitate and oleate remained approximately constant. Verylong chain fatty acids (arachidic, behenic) were increasinglylabelled with time. Lowered incubation temperatures decreased labelling of the saturatedfatty acids. Cu²⁺ increased the proportion of oleate labelledin both algae, and of linoleate in Fucus vesiculosus. This cationdecreased the percentage labelling of stearate and myristatein Ascophyllum nodosum. Lipid metabolism in Ascophyllum nodosumwas more sensitive to raised Cu²⁺ levels than in Fucus vesiculosus Key words: Acyl lipid metabolism, Fucus vesiculosus, temperature effects, Ascophyllum nodosum, copper pollution     

Production of fucoid brown algae <Emphasis Type="Italic">Ascophyllum nodosum</Emphasis> and <Emphasis Type="Italic">Fucus vesiculosus</Emphasis> in the White Sea

Year-round studies of photosynthesis and respiration in the fucoid brown algae Ascophyllum nodosum and Fucus vesiculosus in the White Sea were performed. The annual specific production of the macrophytes was determined to be 1314 and 1642 cal/g of wet weight for A. nodosum and F. vesiculosus, respectively. The total annual production of fucoids (4.88 × 10¹¹ kcal) comprised about 0.8% of the phytoplankton production in the White Sea.     

Water-soluble polysaccharides of Opuntia ficus-indica cv “Burbank's Spineless”

Carbohydrate-containing polymers have been extracted with water from the fleshy, lobed stems of Opuntia ficus-indica cv “Burbank's Spineless”. By ion exchange chromatography, the material was separated into one neutral and two acidic fractions. Each fraction was separated in two by gel filtration. The neutral fractions consisted of two glucans and a glycoprotein, containing arabinose and galactose. All four acidic fractions contained galacturonic acid, arabinose, rhamnose, galactose and xylose in different proportions. The cell wall structure of O. ficus-indica is discussed.     

The metabolism of [3−3H]oleanolic acid-3-O-mono-[14C]glucoside in isolated cells from Calendula officinalis leaves

The radioactive precursor, [3?³H]oleanolic acid-3-O-mono-[¹⁴C]glucoside was administrated to isolated cells obtained from the leaves of Calendula officinalis. The radioactivity of the precursor was incorporated into fractions containing free oleanolic acid, individual glucosides, glucuronide F and other glucuronides. The ratio of ³H: ¹⁴C radioactivity in these fractions indicated that glucosides were formed in a process involving direct glycosylation of the precursor, whereas the glucuronides were formed from oleanolic acid released by hydrolysis of the precursor. Dynamics curves showed that glucoside II formed by direct glycosylation of the precursor was intensively transformed to other derivatives.     

Sialic acid-binding lectins in the “whip scorpion” (Mastigoproctus giganteus) serum

Sialic acid-specific lectins have been detected in the serum of the “whip scorpion,” Mastigoproctus giganteus. When compared to Limulus lectins, Mastigoproctus agglutination profiles for a panel of untreated and enzyme-treated vertebrate erythrocytes were almost identical except for the agglutination of nonhuman primate erythrocytes. However, both chelicerate species exhibited heterogeneous serum lectins which showed some differences in their serological reactivity. At least three distinct specific fractions could be demonstrated in Mastigoproctus serum by crossed absorption and hemagglutination-inhibition experiments. These fractions are specific for sialic acids and/or sialoconjugates but also bind substances such as N-acetylglutamic acid, N-acetylmuramic acid, chitobiose, and chitotriose. These adjunct specificities are important clues in the interpretation of the possible biological role of chelicerate lectins.     

Brown seaweed species from Strangford Lough: compositional analyses of seaweed species and biostimulant formulations by rapid instrumental methods

The aims of this study were to characterise the composition of five seaweed species (Ascophyllum nodosum, Fucus serratus, Fucus vesiculosus, Laminaria hyperborea and Sargassum muticum), their extracts and commercial formulations, using thermogravimetry (TGA), energy dispersive X-ray microanalysis (EDX), Fourier-transform infrared spectroscopy (FTIR) and pyrolysis gas chromatography/mass spectrometry (Py-GC/MS). Analyses of the samples by TGA and EDX provided information on the proportions of algal cell wall, inorganic fractions and minerals. The main carbohydrate constituents of the five species and extracts were identified by their pyrolysis products, e.g. 1-(2-furanyl) ethanone, 5-methyl-2-furcarboxaldehyde, 2-hydroxy-3-methyl-2-cyclopenten-1-one, diannhydromannitol, 1,6-anhydromannopyranose and 1,6-anhydromannofuranose, using Py-GC/MS. The differences in relative intensities of the infrared bands of the five species were enhanced, especially after acid extraction compared with alkaline or neutral treatments, resulting in improved understanding of the compositional changes. In addition four commercial formulations and two acidic extracts of A. nodosum were evaluated for composition using the techniques. The dry matter, pH, electrical conductivity, ash, carbon and nitrogen content of the six preparations showed significant differences in composition. Variations in fatty acid, alginic acid, mannitol, laminarin and fucoidan content of the six formulations were reported. The results have shown that TGA, EDX, Py-GC/MS and FTIR are complementary techniques for rapid evaluation of seaweed materials and products.     

Phenolic acids in the genus Lycopodium

The dihydric phenolics from the leaves of 170 Ecuadorian Lycopodium specimens representing 49 species and varieties have been examined as semiquinones by EPR spectroscopy. An ester of dihydrocaffeic acid was observed in 137 extractors of specimens all confined to the subgenus Urostachya. The ester was not present in the subgenera Lycopodium and Lycopodiella, where the dominant phenolic acid was chlorogenic acid. The concentrations of the “Urostachyaester” were found to increase with increasing altitude. Hydroquinone and protochatechuic acid have been observed in a few specimens.