Radical scavenging capacity and cytoprotective effect of enzymatic digests of <Emphasis Type="Italic">Ishige okamurae</Emphasis>

In order to obtain natural antioxidants of good quality from a marine bioresource, we selected the brown marine alga, Ishige okamurae, which is an abundant and unutilized source of biomass and grows near Jeju Island, South Korea. An enzymatic extraction technique was used in order to determine the antioxidant effects of I. okamurae using commercially available food-grade digestive enzymes. In the evaluation of the radical scavenging capacity of the enzymatic extracts from I. okamurae using an electron spin resonance (ESR) spectrophotometer, all of the enzymatic extracts showed profound dose-dependent radical scavenging abilities. The majority of enzymatic extracts generated by proteases (except for Neutrase) had stronger hydrogen peroxide scavenging effects than the carbohydrase extract. In particular, the cytoprotective effects of the Kojizyme extract against H₂O₂ - induced DNA damage increased significantly with increasing extract concentrations in our comet assay tests. These results showed that I. okamurae may prove to be a valuable natural source of antioxidants.     

NEW INSIGHTS IN THE TAXONOMY OF THE CERAMIUM SINICOLA COMPLEX: RESURRECTION OF CERAMIUM INTERRUPTUM (CERAMIACEAE,RHODOPHYTA)1

Phylogenetic relationships of the Ceramium sinicola complex (C. interruptum and C. sinicola) including C. codicola were studied using nucleotide sequences of rbcL and small subunit rDNA, and the RUBISCO spacer was used for sequence comparison of each species. A reassessment of the taxonomic rank and the evolutionary trend within the complex was inferred from a comparative morphological study and molecular data sets based on 11 samples from eight populations from the Pacific coast of the United States and Mexico. Intraspecific relationships were poorly resolved, but the resurrection of C. interruptum as a distinct species was strongly supported by both morphological and molecular data. Ceramium interruptum is distinguished by the combination of the following features: thalli uncorticated at the first internode above the dichotomy, presence of four corticating filaments, 7–11 segments between branching points, rhizoids digitate, and epiphytic on a variety of hosts. Our molecular analyses show that C. sinicola is the sister group to C. codicola, and C. interruptum is basal to them. These phylogenetic relationships allowed for an assessment of the trend in the evolution of cortication pattern and attachment mode to the host.     

Antifouling activity of seaweed extracts on the green alga Enteromorpha prolifera and the mussel Mytilus edulis

Twenty-seven species of common seaweeds from the coast of Korea havebeen screened for antifouling activity. The seaweed extracts were tested inlaboratory assays against the marine fouling green alga Enteromorphaprolifera and the blue mussel Mytilus edulis. Tissue growth, sporesettlement, zygote formation and germlings of the E. prolifera wereinhibited by methanol extracts of the seaweed Ishige sinicola (= I. foliacea) and Sargassum horneri. Spore settlement was stronglyinhibited by using extract concentrations as low as 30 g mL^-1with I. sinicola and 120 g mL^-1 with S. horneri. The repulsive activity of the foot of the mussel was completely inhibited bymethanol extracts of I. sinicola and Scytosiphon lomentaria atconcentrations of 40 g per 10 L drop supplied to eachmussel. These extracts also showed strong antifouling activities onlarval settlement with, respectively, no or only 6% of the spat settlingwhen a test concentration of 0.8 mg mL^-1 was used. This work isthe first stage towards the development of novel antifouling agents frommarine macroalgae.     

Isolation of antifouling active pyroglutamic acid,triethyl citrate and di-<Emphasis Type="Italic">n</Emphasis>-octylphthalate from the brown seaweed <Emphasis Type="Italic">Ishige okamurae</Emphasis>

Three antifouling active compounds of L-pyroglutamic acid (PGA), triethyl citrate (TEC) and di-n-octylphthalate (DNOP) were isolated from the brown seaweed Ishige okamurae. Approximately 2.8 mg PGA, 1.7 mg TEC, and 2.0 mg DNOP were isolated from 600 g of I. okamurae powder. The concentrations of PGA, TEC, and DNOP required to cause foot repulsion in 50% of mussels (RD₅₀) were 9, 26, and 0.08 mM, respectively. The PGA, TEC, and DNOP concentrations required to inhibit 50% attachment of algal spores (ID₅₀) were 24, 50 and 0.1 mM, respectively. These compounds showed stable antifouling activities against mussel and algal spore attachment.     

Ishigoside, a new glyceroglycolipid isolated from the brown alga Ishige okamurae

A new glyceroglycolipid, ishigoside (1, 2-di-O-palmitoyl-3-O-(6-deoxy-6-amino)-α-D-glucopyranosyl-glycerol, 1), along with two known compounds were isolated from the brown alga Ishige okamurae. The structure of the new compound was determined on the basis of spectroscopic analysis, including 1D and 2D NMR, MS techniques and chemical methods. Moreover, direct free radical scavenging activities of ishigoside were investigated by electron spin resonance spectrometry (ESR) technique. The results suggested that ishigoside was a potential free-radical scavenger against DPPH, hydroxyl, alkyl, and superoxide radicals with the EC₅₀ of 31.2, 16.7, 22.7, and 26.8 μM, respectively.     

超声波协同热水提取铁钉菜多糖的研究

应用超声波技术,研究了液固比、超声波强度、提取时间、提取温度和pH对铁钉菜多糖提取率的影响。结果表明,超声波提取铁钉菜多糖最佳工艺条件为:料剂比为3:100(g:m l),不调pH值,在65℃,超声强度为70%(210w),超声30 m in。     

CLASSIFICATION OF THE GENUS ISHIGE (ISHIGEALES,PHAEOPHYCEAE) IN THE NORTH PACIFIC OCEAN WITH RECOGNITION OF ISHIGE FOLIACEA BASED ON PLASTID rbcl AND MITOCHONDRIAL cox3 GENE SEQUENCES1

The taxonomy and biogeography of a genus with species that occur in geographically isolated regions is interesting. The brown algal genus Ishige Yendo is a good example, with species that apparently inhabit warm regions of both the northwestern and northeastern Pacific Ocean. We determined the sequences of mitochondrial cox3 and plastid rbcL genes from specimens of the genus collected over its distributional range. Analyses of the 86 cox3 and 97 rbcL sequences resulted in congruent trees in which Ishige sinicola (Setch. et N. L. Gardner) Chihara consisted of two distinct clades: one comprising samples from Korea and Japan, and the other comprising samples from the Gulf of California. Additional observations of the morphology and anatomy of the specimens agree with the molecular data. On the basis of results, we reinstated Ishige foliacea S. Okamura (considered a synonym of I. sinicola from the Gulf of California) for plants from the northwest Pacific region and designated a specimen in the Yendo Herbarium (SAP) as the lectotype. I. foliacea is distinguished by large (up to 20 cm) and wide (up to 20 mm) thalli, with a cortex of 4–7 cells, and a medulla composed of long, tangled hyphal cells. Both cox3 and rbcL sequence data strongly support the sister‐area relationship between the northwest Pacific region and the Gulf of California. A likely explanation for this pattern would be the presence of a species ancestral to contemporary species of Ishige in both regions during the paleogeological period, with descendants later isolated by distance.     

A NEW BROWN ALGAL ORDER,ISHIGEALES (PHAEOPHYCEAE), ESTABLISHED ON THE BASIS OF PLASTID PROTEIN‐CODING rbcL,psaA, AND psbA REGION COMPARISONS1

The brown algal family Ishigeaceae currently includes a single genus, Ishige Yendo, with two species. The relationship of the family to other brown algal lineages is less studied in terms of their plastid ultrastructure and molecular phylogeny. We determined the sequences of rbcL from four samples of the two Ishige species and nine putative relatives and the psaA and psbA sequences from 37 representatives of the brown algae. Analyses of individual and combined data sets resulted in similar trees; however, the concatenated data gave greater resolution and clade support than each individual gene. In all the phylogenies, the Phaeophyceae was well resolved, the Ectocarpales being placed in a terminal position and the Ishigeaceae ending up in a basal position. From our ultrastructural study, we concluded that the pyrenoid is absent in the Ishigeaceae, despite the presence of a rudimentary pyrenoid in I. okamurae. These results suggest that the Ishigeaceae is an early diverging brown lineage. Our molecular and morphological data, therefore, lead us to exclude the Ishigeaceae from the Ectocarpales s.l., which have an elaborate pyrenoid, and to propose its own order Ishigeales ord. nov. The Ishigeales is distinguished by oligostichous structure of thalli, phaeophycean hairs formed within cryptostomata, unilocular sporangia transformed from terminal cortical cells, and plurilocular sporangia lacking sterile terminal cells. This study is the first to document the utility of the psaA and psbA sequences for brown algae and also the first report on the multigene phylogeny of the Phaeophyceae based on three protein‐coding plastid genes.     

Algicidal Activity of Glycerolipids from Brown Alga Ishige sinicola toward Red Tide Microalgae

Bioassay-guided fractionation of a methanol extract of the brown alga, Ishige sinicola, led to the isolation of five algicidal compounds. Their structures were determined to be α-monoglycerides of eicosa-5Z,8Z,11Z,14Z-tetraenoic (arachidonic) acid, octadeca-6Z,9Z,12Z,15Z-tetraenoic acid, linoleic acid and oleic acid, and 1-O-palmitoyl-3-O-(6-sulfo-α-D-quinovopyranosyl)-sn-glycerol on the basis of spectroscopic data and a comparison with the data in the literature. These glycerolipids showed moderate-to-high cell lysis activity against the red tide microalgal species, Heterosigma akashiwo, Karenia mikimotoi and Alexandrium catenella, at a concentration of 20 μg/mL.     

Seasonal variation on size and chemical constituents of Sargassum sinicola Setchell et Gardner from Bahía de La Paz, Baja California Sur, Mexico

Investigation on seasonal variation in size and chemical constituents of Sargassum sinicola Setchell et Gardner from Bahía de La Paz, Baja California Sur, Mexico, was carried out from a control bed and compared with an experimental bed with artificial nutrients added. No significant differences were found between the control and experimental thalli for size or chemical composition, except for iodine and raw fiber. For control thalli the results were: size 7.5–56.0 cm, alginate yield 7.2–13.7%, viscosity 58.7–191.7 millipascal seconds (mPa s), mannitol 2.9–8.1%, raw fiber 5.5–7.5% and iodine 0.020–0.141%; while in the experimental thalli the size ranged from 7.5 to 80.3 cm and the alginate yield was 7.8–10.4%, viscosity 41.4–163.4 mPa s, mannitol 2.9–8.3%, raw fiber 5.9–10.7% and iodine 0.021–0.098%. These variations were related to its natural growth cycle, and showed reductions during the senescence period. Results suggest that S. sinicola is not affected by relatively low nutrient concentrations, and could be considered as raw material for alginate production.