Light-harvesting complexes of brown algae. Biochemical characterization and immunological relationships.

The pigment composition of the light-harvesting complexes isolated from several brown algae belonging to different orders has been analysed by reverse-phase HPLC. Relative to whole chloroplasts, they were markedly enriched in Chl c, fucoxanthin and violaxanthin and conversely depleted in Chl a. The relative molar proportions of the 4 main pigments (Chl a/Chl c/fucoxanthin/violaxanthin) ranged from 100:18:76:6 to 100:30:107:17. The protein moiety of LH complexes of all the species studied were composed of one or two main polypeptide components in the range of 19-22 kDa. These polypeptide subunits were arranged in polymeric particles about 240 kDa in Laminaria saccharina. A polyclonal antibody raised against the LH polypeptide of Fucus serratus has been tested on LH apoproteins of other Chromophytes and Chlorophytes. Phylogenic implications of these results are discussed.

An anticoagulant fucoidan from the brown seaweed Ecklonia kurome.

The structure of a alpha-L-fucose-rich, sulphated polysaccharide (C-I) with a potent anticoagulant activity, which was isolated from the brown seaweed Ecklonia kurome, has been studied. Methylation analysis showed that C-I consisted mainly of 3-linked and 3,4-disubstituted fucopyranosyl residues in addition to non-reducing terminal fucofuranosyl and fucopyranosyl residues, 2,3-di- and 2,3,4-tri-substituted fucopyranosyl residues and galactopyranosyl residues with various glycosidic linkages. Methanolysis of C-I gave neutral di-, tri-, tetra- and highly polymerized-oligosaccharide fractions. GC-MS and methylation analysis indicated that di- and trisaccharide fractions consisted mainly of Fuc-(1----3)-Fuc and Fuc-(1----3)-Fuc-(1----3)-Fuc, respectively, in addition to small amounts of Fuc-(1----4)-Fuc, Fuc-(1----4)-Gal and Fuc-(1----3)-[Fuc-(1----2)-]Fuc. When methylated C-I was subjected to methanolysis for desulphation followed by remethylation with deuterated methyl iodide, most of deuteriomethyl groups substituted to position 4 of 3-linked Fuc.

Novel meroterpenoids from Cystoseira mediterranea: use of the crown-gall bioassay as a primary screen for lipophilic antineoplastic agents.

Using a slight modification of the crown-gall potato disc bioassay, we were able to apply this test for two previously described antineoplastic lipophilic metabolites, didemnin B and mediterraneol A [1], and to use it as a guide for chromatographic separations of meroterpenoids from Cystoseira mediterranea. An active compound, mediterraneone [3], was isolated, and its structure was found to be a novel norsesquiterpenoid by chemical and spectral methods.

Anti-plasmin inhibitor. V. Structures of novel dimeric eckols isolated from the brown alga Ecklonia kurome OKAMURA.

6,6'-Bieckol (1), 2-O-(2,4,6-trihydroxyphenyl)-6,6'-bieckol (4), and 8,8'-bieckol (2), bispolyphenols with a dibenzo-1,4-dioxin skeleton, have been isolated as potent anti-plasmin inhibitors from the brown alga Ecklonia kurome OKAMURA. Their structures have been determined to be dimers of eckol linked at the C-6 or C-8 positions, through an aryl-aryl bond on the basis of spectral data. Their inhibitory actions on anti-plasmins (alpha 2-macroglobulin and alpha 2-plasmin inhibitor) and some proteases have been examined.

Turbinaric acid, a cytotoxic secosqualene carboxylic acid from the brown alga Turbinaria ornata.

A moderately cytotoxic secosqualene carboxylic acid designated turbinaric acid [1] has been isolated from the brown alga Turbinaria ornata, and it has been identified to be 4,8,13,17,21-pentamethyl-4,8,12,16,20-docosapentaenoic acid by means of spectral analysis and synthesis.

Interaction of fucoidan from Pelvetia fastigiata with surface antigens of hepatitis B and woodchuck hepatitis viruses.

A sulfated polysaccharide isolated from Pelvetia fastigiata, a marine algae, was found to inhibit in vitro the reaction of the surface antigen of hepatitis B virus (HBsAg) or of woodchuck hepatitis virus (WHsAg) with antibody to HBsAg (anti-HBs). The polysaccharide was composed mainly of 1----2 linked L-fucose-4-sulfate with some (less than 10%) 1----3 linkages. The inhibition of the reaction of HBsAg with anti-HBs or of WHsAg with anti-HBs was found to be directly proportional to the molecular size of the polysaccharide. Comparison of its inhibitory activity with that of carrageenans and dextran sulfates showed that, in addition to the size, the configuration of the component sugar and the presence of deoxy sugar may play a role in the inhibition of reaction of HBsAg or WHsAg with anti-HBs. The fucose sulfate polymer, fucoidan, however, had no effect in vivo on woodchuck hepatitis virus in woodchuck chronic carriers.

Calmodulin-binding proteins are developmentally regulated in gametes and embryos of fucoid algae.

Calcium-binding proteins and calmodulin-binding proteins were identified in gametes and zygotes of the marine brown algae Fucus vesiculosus, Fucus distichus, and Pelvetia fastigiata using gel (SDS-PAGE) overlay techniques. A calcium current appears to be important during cell polarization in fucoid zygotes (K.R. Robinson and L.F. Jaffe, 1975, Science 187, 70-72; K.R. Robinson and R. Cone, 1980, Science 207, 77-78), but there are no biochemical data on calcium-binding proteins in these algae. By using a sensitive 45Ca2+ overlay method designed to detect high-affinity calcium-binding proteins, at least 9-11 polypeptides were detected in extracts of fucoid gametes and zygotes. All samples had calcium-binding proteins with apparent molecular weights of about 17 and 30 kDa. A 17-kDa calcium-binding protein was purified by calcium-dependent hydrophobic chromatography and was identified as calmodulin by immunological and enzyme activator criteria. A 125I-calmodulin overlay assay was used to identify potential targets of calmodulin action. Sperm contained one major calmodulin-binding protein of about 45 kDa. Eggs lacked major calmodulin-binding activity. A 72-kDa calmodulin-binding protein was prominent in zygotes from 1-65 hr postfertilization. Both calmodulin-binding proteins showed calcium-dependent binding activity. Overall, the data suggest that the appearance and distribution of certain calcium-binding and calmodulin-binding proteins are under developmental regulation, and may reflect the different roles of calcium during fertilization and early embryogenesis.

Structure of an anti-plasmin inhibitor, eckol, isolated from the brown alga Ecklonia kurome Okamura and inhibitory activities of its derivatives on plasma plasmin inhibitors.

Eckol (1), a novel phlorotannin with a dibenzo-1,4-dioxin skeleton, has been isolated from the brown alga Ecklonia kurome Okamura as a potent and specific anti-plasmin inhibitor. Its structure has been elucidated based on the spectral data, in particular, by means of negative nuclear Overhauser effect (NOE), and finally established as 1-(3,5-dihydroxyphenoxy)-2,4,7,9-tetrahydroxydibenzo-1,4-dio xin by X-ray analysis. Some partially methoxylated derivatives of eckol were prepared by methylation with diazomethane and also by selective dimethylation of eckol permethylate (1b) to establish the structural requirements for inhibitory activities on alpha 2-macroglobulin and alpha 2-plasmin inhibitor, the main plasmin inhibitors in plasma.

A method for RNA isolation from marine macro-algae.

Sulfated, carboxylic polysaccharides and polyphenols found in marine macro-algae interfere with RNA isolation from these plants and inhibit RNA activities in vitro. Methods based on differential precipitation of RNA or carbohydrates in high salts were used to eliminate the acidic carbohydrates. To protect RNA from inactivation by oxidized polyphenols, strong reducing reagents were used to prevent polyphenol oxidation. RNA was successfully isolated from Macro-cystis pyrifera (brown alga), Porphyra schizophylla (red alga), and Enteromorpha intestinalis (green alga). mRNA isolated from the total RNA was shown to be translationally active.

Levels of zinc, cadmium and lead in some marine algae from Aqaba-Red Sea.

Jordan has witnessed a rapid industrial development in the last twenty years. This has lead to the release of waste materials or pollutants into the marine environment, particularly nearby Aqaba Port. The present study investigates the levels of zinc, cadmium and lead in four brown algae, three red algae and four green algal species collected from Aqaba. Three different levels of lead and zinc concentrations were found: the highest level of both metals is exhibited among brown algae; intermediate level is exhibited among red algae and the lowest level is seen among the green algae. Very low concentrations of cadmium were found in all examined algal species. The results indicate that the brown algal species Cystosira myrica, Sargassum asperifolium, Sargassum neglectum, and Sargassum subrepandum always contain the highest concentrations of lead and zinc, but these algae are less contaminated than brown algae from industrial European seas.

Structure and conformation of two new dolabellane-based diterpenes from Dictyota sp.

Two new dolabellane derivatives (5 and 6) have been isolated from a Dictyota sp. and their structure, including absolute configuration, has been determined on the basis of spectral studies and chemical correlations.

Toxicity of an algal mucopolysaccharide for Escherichia coli and Neisseria meningitidis strains.

Several bacterial strains of clinical significance have been tested to assess the toxic effect of a lectin-like algal mucopolysaccharide from Fucus vesiculosus on their growth. The toxic effect of the mucopolysaccharide has been found to be exerted only on Escherichia coli and Neisseria meningitidis strains. The degree of toxicity, measured by the effect on the growth of the bacteria, is variable depending on the strains of E. coli tested, whereas with N. meningitidis the results obtained indicate homogeneity between the strains, without significative variations among different serotypes even in the same serogroup.

Purification and partial characterization of a Fucus Vesiculosus agglutinin.

Fucus vesiculosus agglutinin has been purified to homogeneity by conventional chromatographic procedures and characterized as a mucopolysaccharide with 90% carbohydrate content. Estimated molecular weight is about 2 X 10(6) daltons. It has no sub-unit structure and its isoelectric point is 3.2. It contains 1.23% S, 0.24% Ca and 0.06% P. Agglutinin mediated sheep red blood cell agglutination was inhibited only by glycoproteins with complex lateral oligosaccharide chains resembling some of the oligosaccharide chains found in the erythrocyte membrane glycoproteins. Metaperiodate treatment of the sheep red cells rendered them non-agglutinable. Sequential degradation of the oligosaccharide chains with glycosidases suggests that inner mannose residues are implicated in the receptor binding-sites for the agglutinin. Consequently we think that this agglutinin can be a lectin or a lectin-like molecule with complex saccharide specificity.

Selective interaction of a Fucus vesiculosus lectin-like mucopolysaccharide with several Candida species.

A complex carbohydrate specific lectin-like mucopolysaccharide extracted from the brown alga Fucus vesiculosus was found to agglutinate Candida guilliermondii cells but not those of other species of the same genus (except for a weak agglutination with C. krusei). The selective binding of this mucopolysaccharide correspondingly affected the growth of the yeasts. The results suggest that there are notable differences--at least with respect to the receptors for the F. vesiculosus mucopolysaccharide--between C. guilliermondii, C. krusei and the other Candida species.

Studies on algal cytochromes. III. Amino acid sequence of cytochrome c-553 from a brown alga, Petalonia fascia.

The amino acid sequence of a photosynthetic cytochrome c-553 isolated from a brown alga, Petalonia fascia was determined by BrCN fragmentation and a solid phase Edman degradation. The cytochrome contains 85 amino acid residues, giving a molecular weight of 9,803. The complete amino acid sequence is as follows: Val-Asp-Ile-Asn-Asn-Gly-Glu-Ser-Val-Phe-Thr-Ala-Asn-Cys-Ser-Ala-Cys-His-Ala-Gly -Gly-Asn-Asn-Val-Ile-Met-Pro-Glu-Lys-Thr-Leu-Lys-Lys-Asp-Ala-Leu-Glu-Glu-Asn-Gl u-Met-Asn-Asn-Ile-Lys-Ser-Ile-Thr-Tyr-Gln-Val-Thr-Asn-Gly-Lys-Asn-Ala-Met-Pro-A la-Phe-Gly-Gly-Arg-Leu-Ser-Glu-Thr-Asp-Ile-Glu-Asp-Val-Ala-Asn-Phe-Val-Ile-Ser-Gln-Ser-Gln-Lys-Gly-Trp. The highest homology was found between the sequences of cytochromes c-553 of P. fascia and Alaria esculenta, the next between those of P. fascia and Porphyria tenera.

Gibberellin- and cytokinin-like activities in marine algae from central Mediterranean.

The distribution of gibberellin- and cytokinin-like activities in twenty-one species of mediterranean algae belonging to Phaeophyta and Rhodophyta has been investigated. Fractions containing each of these activities have been obtained by partitioning aqueous-methanolic extracts of algae against ethyl acetate and butanol successively at different pH values. The stimulation or inhibition of amaranthin synthesis in Amaranthus sp. seedlings have been used a biological tests to assay the cytokinin- or gibberellin-like activities respectively. One or both these two hormonal activities have been detected in all species examined. While cytokinin-like activity has been found with the same frequency in the two phyla, the gibberellin-like activity was less frequent in Phaeophyta.