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The East China Sea (ECS) has long been considered an important monitoring site for oceanic ecosystem changes because many water currents and river discharges constantly influence this area. In this study, the community structure and diversity of phytoplankton in the northern part of the ECS adjacent to Jeju Island were explored using small subunit ribosomal RNA (SSU) pyrosequencing. We analysed samples collected from four stations from the surface and at 30-m and 50-m depths during April and September 2011. We observed spatial and temporal variations in the phytoplankton community. Among phytoplankton, diatoms and dinoflagellates constituted a major portion at all stations (60–90%). However, comparison of the April and September samples showed seasonal variation and shifts in the dispersion of diatom and dinoflagellates among stations. Among stations, diatoms dominated St. 1 and others were dominated by dinoflagellates. Furthermore, phylotypes of potentially toxin-producing genera such as Karlodinium, Heterocapsa, Gymnodinium, Gyrodinium, and Pseudo-nitzschia were dominant in this area.

Marine Chlorella ellipsoidea protein was hydrolyzed using Protamex, Kojizyme, Neutrase, Flavourzyme, Alcalase, trypsin, α-chymotrypsin, pepsin and papain. Alcalase-proteolytic hydrolysate exhibited the highest ACE inhibitory activity among them and was fractionated into three ranges of molecular weight (below 5 kDa, 5–10 kDa and above 10 kDa). The below 5 kDa fraction showed the highest ACE inhibitory activity and was used for subsequent purification steps. During consecutive purification, a potent ACE inhibitory peptide from marine C. ellipsoidea , which was composed of 4 amino acids, Val–Glu–Gly–Tyr (MW: 467.2 Da, IC 50 value: 128.4 μM), was isolated. Lineweaver–Burk plots suggest that the peptide purified acts as a competitive inhibitor against ACE and stable against gastrointestinal enzymes of pepsin, trypsin and α-chymotrypsin. Furthermore, antihypertensive effect in spontaneously hypertensive rats (SHRs) also revealed that oral administration of purified peptide can decrease systolic blood pressure significantly. The results suggest that marine C. ellipsoidea would be an attractive raw material for the manufacture of antihypertensive nutraceutical ingredients.

We report for the first time on the annual gametogenesis of the Burchardi's cockle, Acrosterigma (=Vasticardium) burchardi (Dunker, 1877) on a subtidal sand flat off southern Jeju Island, Korea. Seasonal changes in gamete development and oocyte size were investigated using histology. Intermingled ovaries and testis in the gonads located in the foot indicated that, like other cockles, A. burchardi is a functional hermaphrodite. In August, early developing oocytes and spermatogonia were observed in gonads suggesting that gametogenesis commenced when the water temperature reached 22.7–28.5EC. Early vitellogenic oocytes 8–10 μm in diameter appeared in gonads from September to November when water temperatures ranged from 16.9 to 22.2°C. Oocyte size increased exponentially from November (8 μm) to April (53 μm). Condition index dropped dramatically from May (0.51) to June (0.38), indicating that the Burchardi's cockles off southern Jeju Island spawned during this period. A. burchardi spawning appeared t...

Interest in plant-derived food additives has increased recently, with efforts to identify natural antioxidant sources to replace synthetic antioxidants. This study evaluated the antioxidant effects of organic solvent fractions of 80% methanol extracts from Pediastrum duplex and Dactylococcopsis fascicularis microalgae. Among the solvent fractions tested, the ethyl acetate and n-hexane fractions from P duplex effectively scavenged 79.8% and 74.5% of DPPH free radicals, respectively. The chloroform fraction from D. fascicularis showed the strongest scavenging ability (49.7%). The greatest scavenging of hydroxyl radicals (73.1%) was exhibited by the 80% methanol extract from P duplex. Aqueous residue and ethyl acetate fraction from P duplex provided the strongest nitric oxide scavenging (57.7%) and metal chelating effect (82.1%), respectively. Chloroform and ethyl acetate fractions from P duplex and n-hexane fraction from D. fascicularis exhibited significantly greater inhibition of lipid peroxidation than the commercial antioxidants. These results suggested that P duplex and D. fascicularis microalgae having potential anti oxidative compounds with various properties could be utilized in the food and pharmaceutical industries.

In this study, we assessed the antioxidant properties of tidal pool microalgae, Halochlorococcum porphyrae and Oltamannsiellopsis unicellularis, from Jeju Island, Korea. Specifically, the antioxidant activity of fractions isolated from 80% methanol extract, and digests produced from five proteases and carbohydrases, were investigated. Almost all the fractions and the 80% methanol extract exhibited higher effects on 1,1-Diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging. The ethyl acetate fraction showed the highest superoxide anion scavenging activity, while both n-hexane and chloroform fractions exhibited higher H2O2 scavenging activity. Among the enzymatic digests from H. porphyrae and O. unicellularis, all the digests exhibited remarkable DPPH scavenging activities. In nitric oxide inhibition, all the digests recorded significantly higher effects than those of the commercial antioxidants (p < 0.05). Flavozyme and Neutrase digests from H. porphyrae, and Termamyl and Alcalase digests from O. unicellularis, showed significant effects in metal chelating. Lipid peroxidation was significantly inhibited in the ethyl acetate fraction, in the Celluclast and Protamex digests from H. porphyrae, and in the chloroform fraction from O. unicellularis. These findings suggest that the two tidal pool microalgae tested in this study are rich in potential antioxidative compounds, the specific properties of which can be considered for use in the food and pharmaceutical industries.

We isolated the unialgal strain of Cylindotheca closterium (Ehrenb.) Reimann et J. C. Lewin and produced an axenic strain using an antibiotic cocktail of enriched f/2 artificial seawater medium. The optimal growth conditions were estimated under 27 different combinations of temperature, salinity, and nutrients, and mass culture was performed based on the best specific growth conditions. Its antioxidant activities were determined from the extracts of methanol, water, and enzymes (proteases and carbohydrases). The maximum specific growth rate (μmax ) varied from 0.63 to 0.97 · d(-1) . The maximum cell density was 7.20 × 10(4) cells · mL(-1) , while the μmax was 0.82 · d(-1) in culture conditions of 20°C, 30 psu (practical salinity unit), and "F" nutrient concentrations on day 10 of the culture period. The scavenging rates for 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical were 72.5% and 69.4% from Viscozyme and methanol extracts, respectively. The enzymatic extracts of C. closterium prepared by the hydrolyses of Amyloglucosidase (AMG) and Viscozyme showed 45.8% and 45.5% nitric-oxide-scavenging rates, slightly lower than the activity of alpha-tocopherol (α-tocopherol) but similar to butylated hydroxytoluene (BHT). The extract from methanol and water showed 44.8% and 44.4% scavenging rates, statistically similar with BHT. The metal-chelating activities of the Kojizyme, Alcalase, methanol, Viscozyme, and Neutrase extracts were 67.1, 53.9, 53.2, 52.1, and 50.2 %, respectively, five to six times higher than the commercial antioxidants. The AMG, Viscozyme, and Neutrase extracts showed a remarkable linoleic acid peroxidation inhibition, which was higher than BHT and statistically similar with α-tocopherol.

In this study, we focused on natural water-soluble antioxidants from fresh water microalgae, Pediastrum duplex and Dactylococcopsis fascicularis from Jeju Island, Korea. They were prepared by enzymatic digestion using five carbohydrases (Viscozyme, Celluclast, AMG, Termamyl and Ultraflo) and five proteases (Protamex, Kojizyme, Neutrase, Flavourzyme and Alcalase), and the potential antioxidant activity of each was assessed. All enzymatic digests from P. duplex showed significant DPPH scavenging effects. Termamyl (60.6%) digest from P. duplex possessed the highest effects on hydrogen peroxide scavenging. Celluclast (58.1%) and Kojizyme digests (56.9%) from D. fascicularis possessed higher effects on superoxide anion radical scavenging. All enzymatic digests exhibited significant effects on both NO· scavenging and metal chelating. Lipid peroxidation was significantly in inhibited Viscozyme, Termamyl and Kojizyme digests from P. duplex and Ultraflo, Protamex, Kojizyme and Alcalase digests from D. fascicularis. These data suggest that enzymatic digests of the fresh water microalgae, P. duplex and D. fascicularis might be valuable sources of antioxidant which can be applied in food and pharmaceutical industry.

Reactive oxygen species (ROS) such as hydrogen peroxide, hydroxyl radicals and superoxide anions, which are produced because of exogenous factors (tobacco smoke, ionizing radiation and certain pollutants) and endogenous factors (normal aerobic respiration) have been implicated in cellular processes such as mutagenesis, carcinogenesis and premature aging. ROS have the ability to react with a large variety of easily oxidisable cellular components, such as proteins, lipids and lipoproteins (Fridovich 1995). Oxidation is one of the major reasons of food deterioration, resulting to the destruction of fat-soluble vitamins and development of off colors and toxicants (Yang et al. 2000; Ukeda et al. 2002). Besides, in the food industry lipid peroxidation is an important deteriorative reaction during processing and storage. Commercial antioxidant supplements such as butylated hydroxyl anisole (BHA), butylated hydroxy tolouene (BHT), α-tocopherol and propyl gallate (PG) have been used in order to reduce oxidative damages in human body (Sherwin 1990; Gulcin et al. 2002). However, it is suspected that those antioxidants are responsible for some side effects such as liver damage and carcinogenesis. Antioxidants are involved with the oxidation mechanism by scavenging free radicals, chelating catalytic metals and by acting as oxygen scavengers (Shahidi and Wanasundara 1992; Buyukokuroglu et al. 2001). As a natural antioxidant source, plants have an ability to absorb the sun’s radiation for generating high levels of oxygen as secondary metabolites of photosynthesis. Oxygen is easily activated by ultra violet (UV) radiation and heat from the sunlight to produce toxic ROS. Therefore, plants produce various antioxidative comAlgae Volume 24(1): 47-55, 2009

In this study, we focused on natural water-soluble antioxidants from the Jeju benthic diatoms, Achnanthes longipes, Navicula sp. and Amphora coffeaeformis. They were prepared by enzymatic digestion using five carbohydrases (Viscozyme, Celluclast, AMG, Termamyl and Ultraflo) and five proteases (Protamex, Kojizyme, Neutrase, Flavourzyme and Alcalase) and their potential antioxidant activity was assessed. Among the enzymatic digests, Neutrase digest from A. coffeaeformis exhibited the highest effect in DPPH radical scavenging. Flavourzyme (48.7%), Viscozyme (47.4%) and Celluclast (45.7%) digests from Navicula sp. exhibited higher O.?₂ radical scavenging activity. Viscozyme digest from A. coffeaeformis (45.9%) possessed the highest effects in hydroxyl radical scavenging. Termamyl (89.3%) and Protamex (88.8%) digests from A. coffeaeformis had strong metal chelating activity. Lipid peroxidation was significantly inhibited in Termamyl and Kojizyme digests from A. longipes, AMG and Termamyl digests from Navicula sp. and Kojizyme digest from A. coffeaeformisi. These data suggest that enzymatic digests of the Jeju benthic diatoms might be valuable sources of antioxidant which can be applied in food and pharmaceutical industry.

Benthic diatoms are a commonly used food source in shellfish aquaculture. Diatoms of the genus Navicula are the most abundant benthic diatoms occurring year-round on the coast of Jeju Island, Korea. We isolated an axenic strain of N. incerta Grunow; estimated its growth characteristics under 27 different combinations of temperature, salinity, and nutrients; and determined its biochemical composition and antioxidant activities. The maximum specific growth rate (lmax), defined as the increase in cell density per unit time, was 0.81‐1.04 AEd )1 , and the maximum cell density, 7.99 · 10 5 cells AEmL )1 , was reached at 0.88 AEd )1 lmax ,2 0� C, 30 psu salinity, and F ⁄2 nutrient concentration on day 12 of the culture period. The approximate cellular composition was as follows: 7.0 ± 0.04% protein, 1.7 ± 0.28% lipid, 12.8 ± 0.85% carbohydrate, 68.4 ± 0.09% ash, and 10.1 ± 0.44% moisture. The antioxidant properties of N. incerta were determined for various extracts. The rates of 1,1-diphenyl-2-picrylhydrazyl (DPPH) free-radical scavenging for Neutrase and methanol extracts were 81.6% and 62.8%, respectively. Flavourzyme extract had a superoxidescavenging rate of 57.7%. Kojizyme and Ultraflo extracts had nitric-oxide-scavenging rates of 42.2% and 40.6%, respectively, significantly higher than commercial antioxidants, such as a-tocopherol and butylated hydroxytoluene (BHT). The metalchelating activities of the methanol, Neutrase, and Termamyl extracts were 68.5%, 45.2%, and 41.2%, respectively, four to six times higher than commercial antioxidants. The Termamyl extract showed the highest linoleic acid peroxidation inhibition, exceeding a-tocopherol and on par with BHT.

The dynamics of phytoplankton abundance with seasonal variation in physicochemical conditions were investigated monthly at 10 stations around the Chagwi-do off the west coast of Jeju Island, Korea, including inshore, middle shore, and offshore in the marine ranching area from September 2004 to November 2005. Water temperature varied from 12.1 to 28.9°C (average 18.8°C), and salinity from 28.9 to 34.9 psu (average 33.7 psu). The chlorophyll a concentration was 0.02-2.05 µg L1 (average 0.70 µg L1), and the maximum concentration occurred in the bottom layer in April. A total of 294 phytoplankton species belonging to 10 families was identified: 182 Bacillariophyceae, 52 Dinophyceae, 9 Chlorophyceae, 12 Cryptophyceae, 6 Chrysophyceae, 4 Dictyophyceae, 13 Euglenophyceae, 6 Prymnesiophyceae, 5 Prasinophyceae, and 5 Raphidophyceae. The standing crop was 2.21-48.69x104 cells L1 (average 9.23x 104 cells L1), and the maximum occurred in the bottom layer in April. Diatoms were most abundant throughout the year, followed by dinoflagellates and phytoflagellates. A phytoplankton bloom occurred twice: once in spring, peaking in April, and once in autumn, peaking in November. The spring bloom was represented by fourChaetoceros species andSkeletonema costatum; each contributed 10–20% of the total phytoplankton abundance. The autumn bloom comprised dinoflagellates, diatoms, and phytoflagellates, of which dinoflagellates were predominant.Gymnodinium conicum, Prorocentrum micans, andP. triestinum each contributed over 10% of the total phytoplankton abundance.

The enzymatic extracts from seven species of microalgae (Pediastrum duplex, Dactylococcopsis fascicularis, Halochlorococcum porphyrae, Oltmannsiellopsis unicellularis, Achnanthes longipes, Navicula sp. and Amphora coffeaeformis) collected from three habitats (freshwater, tidal pool, and coastal benthic) at Jeju Island in Korea were investigated for their antioxidant activity. Of the extracts tested, the AMG 300 L (an exo 1, 4-alpha-D-glucosidase) extract of P. duplex, the Viscozyme extract of Navicula sp., and the Celluclast extract of A. longipes provided the most potential as antioxidants. Meanwhile, the Termamyl extract of P. duplex in an H(2)O(2) scavenging assay exhibited an approximate 60% scavenging effect. In this study, we report that the DNA damage inhibitory effects of P. duplex (Termamyl extract) and D. fascicularis (Kojizyme extract) were nearly 80% and 69% respectively at a concentration of 100 microg/ml. Thus, it is suggested that the microalgae tested in this study yield promising DNA damage inhibitory properties on mouse lymphoma L 5178 cells that are treated with H(2)O(2). Therefore, microalgae such as P. duplex may be an excellent source of naturally occurring antioxidant compounds with potent DNA damage inhibition potential.

Benthic diatoms are known as a good food for shellfish in nature and in commercial hatchery of Jeju Island, Korea. Grammatophora marina is commonly found as dominant benthic micro-algae in Jeju coastal waters throughout the year. To know the best growth conditions of this species, culture was done in terms of three parameters; water temperature, salinity and nutrients. Each parameter was controlled by temperature of 15, 20 and 25°C; salinity of 25, 30 and 35 psu; and nutrient concentrations of 50, 100 and 200%. F/2 media was used with artificial seawater for the culture, which was continued for two weeks with L:D cycle 12:12 by using fluorescent light. Maximum specific growth rate was recorded 1.68 d ‐1 at temperature of 25°C with salinity of 35 psu and nutrient concentration of 200% on 6 th day during the culture period. Maximum biomass was also observed 4.9 × 10 5 cells mL ‐1 in the same condition. This species may belong to the euryhaline and eutrophic habitat with warm condition. For nutritional aspects of this species, protein, lipid and carbohydrate were measured. The value of protein, lipid and carbohydrate was 4.96%, 15.82% and 5.65%, respectively. The antioxidant activities of 80% methanolic extract were 46.7%, 23.7% and 23.8% on DPPH (1,1-Diphenyl-2-picrylydrazy) radical, superoxide anion radical and hydrogen peroxide scavenging, respectively. Percentage metal chelating activity was 81.2%. Enzymatic extracts of Alcalase and Ultraflow showed remarkable scavenging activities on DPPH radical (86.5% and 57.2%, respectively), and superoxide anion scavenging activities were 45.3% and 41.4% from Kojizyme and Viscozyme extracts, respectively. Extract of Protomex revealed 24.8% activity on hydrogen peroxide and Neutase showed 30.8% on hydroxyl radical scavenging effects. Celluclast and Viscozyme extracts showed 33.2% and 32.1% activities on nitric oxide scavenging, respectively, while Alcalase showed 61.5% on metal chelating. This species contains higher lipids among the biochemical compounds and higher metal chelating activities from both 80% methanolic and enzymatic extracts.

The purpose of this study was to compare the clinical utility of fluoride-18 positron emission tomography (¹⁸F-PET)/CT with that of conventional (99m)Tc-methylene diphosphonate (MDP) bone scan in temporomandibular disorder (TMD) with osteoarthritis.24 patients with TMD who underwent both ¹⁸F-PET/CT and (99m)Tc-MDP bone scans for diagnostic work-up were enrolled. The temporomandibular joint (TMJ)-to-skull uptake ratio, TMJ-to-muscle uptake ratio and TMJ-to-spine uptake ratio on ¹⁸F-PET/CT and the TMJ uptake ratio on bone scan were measured.Of the 48 TMJs in 24 patients, 35 TMJs were diagnosed as TMD with osteoarthritis, 8 TMJs as TMD with anterior disc displacement (ADD), and the remaining 5 TMJs showed no evidence of TMD (NED). All three uptake ratios on ¹⁸F-PET/CT and the TMJ uptake ratio on the bone scan tended to be higher in TMD with osteoarthritis than in TMD with ADD or NED. Receiver operating characteristic (ROC) curve analysis for detecting TMD with osteoarthritis indicated that the TMJ-to-skull uptake ratio, TMJ-to-muscle uptake ratio and TMJ-to-spine uptake ratio on PET/CT (0.819, 0.771 and 0.813, respectively) showed higher area under the ROC curve value than the TMJ ratio on bone scan (0.714). The TMJ-to-skull uptake ratio on PET/CT showed the highest sensitivity (89%) and accuracy (81%) of all uptake ratios.¹⁸F-PET/CT can help diagnose TMD with osteoarthritis with superior diagnostic ability and is a suitable alternative modality to a conventional (99m)Tc-MDP bone scan.