Han Gil Choi

Ulva conglobata, a marine algae, has neuroprotective and anti-inflammatory effects in murine hippocampal and microglial cells

It has been reported that inflammatory processes are associated with the pathophysiology of Alzheimers disease (AD), and the treatment of AD using anti-inflammatory agents slows the progress of AD. Marine algae have been utilized in food products as well as in medicine products for a variety of purposes. In this study, we investigated the neuroprotective effects of methanol extracts of Ulva conglobata (U. conglobata), a marine algae, on glutamate-induced neurotoxicity in the murine hippocampal HT22 cell line and the anti-inflammatory effects on interferon gamma (IFN-gamma)-induced microglial activation in BV2 cells. U. conglobata methanol extracts significantly attenuated the neurotoxicity induced by glutamate in HT22 cells and inhibited nitric oxide production induced by IFN-gamma in BV2 cells. U. conglobata methanol extract treatments were also examined and it was found that they almost completely suppressed the expression of the proinflammatory enzyme cyclooxygenase 2 (COX-2) and inducible nitric oxide synthase (iNOS). These results suggest that U. conglobata possesses therapeutic potential for combating neurodegenerative diseases associated with neuroinflammation.

Effects of temperature and salinity on the growth of Gracilaria verrucosa and G. chorda, with the potential for mariculture in Korea

Effects of temperature and salinity on the growth of the two agarophytes, Gracilaria verrucosa (Hudson) Papenfuss and Gracilaria chorda Holmes were examined in Korea. Both species grew over a wide range of temperatures (10–30 ∘C) and salinities (5–35‰), and grew well at 17–30 ∘C and a salinity of 15–30‰. In culture, G. verrucosa grew faster than G. chorda and their maximum growth rates were 4.95% day−1 (30 ∘C, 25‰) and 4.47% day−1 (at 25 ∘C, 25‰), respectively. In the field population the maximum growth and fertility of G. chorda were observed in summer. The growth rate of G. verrucosa was slightly higher than that of G. chorda for 2 weeks on the cultivation rope and in culture but it was much lower after being contaminated with epiphytes. The biomass of the epiphytes was 0.82 g dry wt. per host plant in G. verrucosa and 0.001 g in G. chorda. G. chorda exhibited resistance to epiphytism and grew 7 times in length and the dry weight increased 15 times after 55 days. In conclusion, G. chorda appears to be a good agarophyte with a fast growth rate and resistance to epiphytesm, and compared with G. verrucosa, has good potential for commercial cultivation.

Effects of daylength, irradiance and settlement density on the growth and reproduction of Undaria pinnatifida gametophytes

The effects of daylength, irradiance and spore settlement density on the growth, maturation and sporophyte production of Undaria pinnatifida (Harvey) Suringar gametophytes were examined using a factorial experimental design in culture. The growth of Undaria gametophytes increased with increasing daylength (8, 12 and 16 h), but the maximum fertility occurred at a daylength of 12 h followed by 8 and 16 h. Gametophytes grew better at the 16 h daylength under the same mean daily irradiance (MDI) of 20 μmol photons m−2 s−1. However, the fertility was higher at the short daylength (8 h), indicating that the maturation of U. pinnatifida gametophytes is influenced by daylength rather than by the MDI. Vegetative growth and sporophyte production of gametophytes were better at 60 μmol photons m−2 s−1 than at 30 μmol photons m−2 s−1 under a 8:16 h LD (Light: Dark) cycle, and their growth and maturation were density-dependant in 16 and 12 h daylength, respectively. These results suggest that the U. pinnatifida gametophytes require a certain amount of light for the growth and reproduction, and intraspecific competition occurred under the optimal growth and maturation conditions. However, the sporophyte recruits per unit has been enhanced with increasing spore settlement density at 8 and 12 h daylengths indicating that high settlement density gives a benefit for maintaining population, even though the sporophyte production of each female plant is inhibited. In conclusion, the vegetative growth, reproduction and sporophyte production of U. pinnatifida gametophytes are retarded at a low irradiance above growth saturation and a high settlement density, and are determined by daylength.

Seasonal Community Structure and Vertical Distribution of Medicinal Seaweeds at Kkotji in Taean Peninsula, Korea

Marine algal flora and community structure of medicinal seaweeds were examined at Kkotji of Taean Peninsula, Korea from May 2005 to January 2006. Seventy-nine seaweeds including 42 medicinal algae and one marine plant were identified. Sargassum thunbergii was the representative alga occurred at all seasons and shore levels. The dominant medicinal seaweeds were perennial S. thunbergii, Neorhodomela aculeata, and Corallina pilulifera, and ephemeral Monostroma grevillei, Porphyra yezoensis, and Ulva pertusa. Their vertical distribution were N. aculeata – P. yezoensis, M. grevillei, and U. pertusa – C. pilulifera from high to low intertidal zone. The average biomass of medicinal seaweeds varied from 34.17 g m–2 in spring to 56.41 g m–2 in summer. At Kkotji shore, the opportunistic species (Enteromorpha, Ulva, and Cladophora) and turf-forming algae (Caulacanthus okamurae and Gelidium divaricatum) were easily observed. Such fast growing ESG II (ecological state group) was 87.50% and slow growing perennial algae, ESG I was only 12.15%. Also, diversity index (H’) and dominance index (DI) indicate that the seaweed community of Kkotji is unstable. Therefore, Kkotji rocky shore should be more protected from human activities such as turbulence and eutrophication in order to maintain species diversity and abundance of medicinal seaweeds.

Temporal Variations in Seaweed Biomass in Korean Coasts: Woejodo and Jusamdo, Jeonbuk

해조류는 이산화탄소(CO2)와 태양에너지를 이용하여 광 합성을 하는 해양생태계의 일차생산자로서 어류 또는 무척 추 동물을 포함하여 다양한 해양생물의 먹이와 산란장, 생육 장 및 은신처 등 생태학적으로 중요한 역할을 수행하여 먹이 사슬의 상위생물량을 조절하는 기반을 제공한다(Worm et al. 2000; 김과 최 2004; 이 등 2007; 김과 신 2007). 이외에도, 해조류는 부영양화 해역에서 영양염을 제거하는 생물정화자 로서의 기능(Hemminga et al. 1999)과 부착 동∙식물의 착 생기질로 사용되므로 해양생태계 생물다양성에 지대한 영향 을 준다(McCall et al. 1999). 또한, 해조류는 아가, 알긴산 및 캐러기난과 같은 해조산업의 원료와 식용 및 약용으로 사용 되고 있으며(Tseng 1981; Oh et al. 1990), 최근에는 유가 상 승과 온실가스의 주범인 화석연료를 대체할 바이오에탄올의 원료와 온실가스인 CO2를 제거하는 나무를 대체할 종이의 원료(예, 우뭇가사리)로도 관심을 받고 있다(Bastianoni et al. 2008). 따라서, 해조류의 생태적 기능, 환경정화 기능, 유용 종의 생물량, 바이오연료와 종이원료로서의 가능성 확인 및 해양 생태계의 안정성을 파악하기 위해서는 연안에 서식하 는 해조류의 생물량과 이들을 구성하는 주요종의 실태를 파 Algae Volume 23(4): 335-342, 2008

Effects of Thermal Effluents from Wolseong Nuclear Power Plant on Macroalgal Composition and Community Structure

Marine algal flora and community structure were seasonally examined at three sites in the vicinity of the Wolseong nuclear power plant in Korea from February to November 2006. A total of 126 seaweeds including 25 green, 31 brown, 70 red algae, and 1 marine plant were identified. The greatest number ...

Antioxidant and Antimicrobial Activity of Zostera marina L. Extract

Methanol crude extract of the sea grass Zostera marina L. and organic solvent fractions (n-hexane, chloroform, ethyl acetate, n-butanol, and water) were screened for antioxidant activity (total phenolic contents, DPPH scavenging activity, and reducing power) and antimicrobial activity against three human skin pathogens, two bacteria and a yeast; Staphylococcus aureus, Staphylococcus epidermidis, and Candida albicans. Total phenolic contents and 2, 2diphenyl-1-picrylhydrazyl (DPPH) scavenging activity were highest in the ethyl acetate fraction with 968.50 μg gallic acid equivalent per milligram of extract, and ca. 95% scavenging activity on the DPPH radicals at 10 mg ml –1 . In antimicrobial activity tests, MICs (Minimum Inhibitory Concentration) of each Zostera marina extract partitioned ranged from 1mg to 8 mg ml –1 (extract/ 10% DMSO) against all three human skin pathogens. The MICs of the ethyl acetate and n-butanol fractions were the same with 1 mg ml –1 against S. aureus and C. albicans. The ethyl acetate fraction of Z. marina does protect against free radicals and may be used to inhibit the growth of human skin pathogens.

Phenology of Chondrus ocellatus in Cheongsapo Near Busan, Korea

The reproductive phenology of Chondrus ocellatus and the effects of temperature and light on its growth were examined in Cheongsapo near Busan, Korea, from September 1994 to August 1995. The vegetative plants dominated over the year, with a peak occurrence in January. Gameto- and tetrasporophytes were most abundant in November and August. All vegetative and reproductive plants had a peak both in length and weight in October, when seawater temperature was highest (24°C). In laboratory culture, the maximum relative growth rate (RGR) of 2.94% day−1 was obtained at 20°C and 100 μmol photons m−2 s−1, whereas the lowest value was recorded at 25°C and 100 μmol photons m−2 s−1 in a 12: 12 h LD photoperiod regime. Among the three photoperiod regimes (8:16 h, 12:12 h, 16:8 h LD) tested, there was evidence of a higher RGR in the 12:12 h LD cycle. This result suggests that the growth and reproduction of C. ocellatus are correlated with the seawater temperature based on laboratory culture and field observations.

Macroalgal Community Structure on the Rocky Shores of Ongdo, Jusamdo, and Woejodo Islands of the Yellow Sea, Korea

The benthic algal community structures of the seaweed biomass, vertical distribution of dominant seaweeds, and species composition were examined on the rocky shores of Ongdo, Jusamdo, and Woejodo Islands, Korea, in August 2006. A total of 68 seaweeds were identified, comprising 5 green, 11 brown, and 52 red algae from the three study sites. The number of species at Ongdo (32 species) was less than that at Jusamdo (45 species) and Woejodo (44 species). Jusamdo exhibited the maximum seaweed biomass (73.99 g dry wt/m 2 ), while the minimum value was found at Woejodo (36.90 g dry wt/m 2 ). On the three islands, coarsely branched forms were the most dominant functional group in terms of species number and biomass among benthic algal species. The dominant species were Gelidium amansii, Chondrus ocellatus, and Chrysymenia wrightii at Ongdo, Sargasum thunbergii, Ulva pertusa, and Sargassum fusiformis at Jusamdo, and U. pertusa, Undaria pinnatifida , and Corallina pilulifera at Woejodo. Perennial seaweeds were abundant at Ongdo (G. amansii and C. ocellatus) and Jusamdo (S. thunbergii and S. fusiformis), whereas the sheet form of U. pertusa was relatively abundant at Woejodo Island.

Seasonal Variation in Biomass and Community Structure of Intertidal Seaweeds at Heuksando and Hongdo, Southwestern Coast of Korea

해양생태계에서 일차생산자의 중요한 구성원의 하나인 해조 류는 무척추동물과 척추동물의 산란장과 섭이장 그리고 포식 자에 대한 은신처뿐만 아니라, 부착 동·식물에게는 착생기질로 이용되므로 해양생물의 종다양성과 생산성을 증대에 일조한다 (Lindstrom, 2009). 온대해역의 해조류 군집구조는 계절적으로 변화하는 수온, 염분 및 광주기 등 무생물적 환경요인(Lobban and Harrison, 1997)과 경쟁과 섭식압 등의 생물학적요인, 그리 고 인간의 직·간접적 활동(부영양화, 퇴적물의 증가 등)에 따라 변화한다(Tribollet and Vroom, 2007). 특히, 인간활동에 기인 한 환경오염이나 부영양화가 발생한 해역에서는 해조류의 종 다양성이 낮고 단순화된 군집구조를 가지는 것으로 알려져 있 어 해조상과 군집구조로 생태계의 환경변화를 예측 혹은 진단 할 수 있어 생물학적 지시자(biological indicator)로 사용된다 (Diez et al., 1999; Wells et al., 2007). 우리나라 전라남도 연안은 해안선의 굴곡이 심하고 다양한 크 기의 많은 섬들로 구성되어 있을 뿐만 아니라, 해류, 수온, 수심 과 탁도의 변화가 매우 심한 해황적 특성을 보인다(Kang, 1966; Choi, 1992). 전라남도 해역에서 해조류 연구의 시초는 정약전 이 1814년에 집필한 자산어보에서 흑산도에 35종이 출현한 것 으로 기록되어 있는 것이며, 해조학자인 Kang (1966)은 한국 산 해조류의 지리적 분포를 구분하면서 대흑산도와 소흑산도에 서 89종이 생육하는 것을 보고하였다. 이후 Lee et al. (1986a) 은 대흑산도와 소흑산도를 포함한 6개 섬의 하계 조사에서 129 종을 기재하였고 Kang (1966)의 연구 결과와 비교하여 이곳 에 서식하는 해조류는 총 160종으로 기록하였다. 이외에도 홍 도와 흑산도가 포함된 행정구역인 신안군의 우이도의 계절별