Hyun-Woung Shin

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 μg mL-1with I. sinicola and 120 μg 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 μg per 10 μL 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.

Forest fire ash impact on micro- and macroalgae in the receiving waters of the east coast of South Korea

Mountain forest fire ash flushed into the eastern coastal waters of South Korea is known to contain cadmium as one of its significant constituents. To study its impact, two representatives of the micro- and macroalgal communities, Ulva pertusa and Nannochloropsis oculata, were exposed to the concentration range of Cd indicated from the forest fire localities. At low concentrations of 0.224-0.448 mg L(-1), a 20% reduction in growth rate of N. oculata was observed. Chlorophyll a pigment concentration was proportionate to the growth reduction while at higher concentrations (1.792 mg L(-1)) pigments were completely leached. In the macrophyte U. pertusa, a similar trend of pigment leaching was observed. Bioaccumulation factors obtained for these rapidly growing algal species revealed excessive bioconcentration of Cd. Variations in the concentration of Cd among the samples collected along the Korean coast clearly indicated the additional source of metal influx from the forest fires.

Isolation of antifouling active pyroglutamic acid, triethyl citrate and di-n-octylphthalate from the brown seaweed Ishige okamurae

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.

Acute toxicity of organic antifouling biocides to phytoplankton Nitzschia pungens and zooplankton Artemia larvae

The toxicity of the antifouling biocides Irgarol 1051, Diuron, Chlorothalonil, Dichlofluanid, Sea-nine 211, Copper pyrithione, Zinc pyrithione, Ziram and Zineb were evaluated on Nitzschia pungens and Artemia larvae. Results showed that EC50 for Irgarol 1051 was 0.586μgl-1 was the strongest effect on N. pungens following by Copper pyrithione (4.908μgl-1), Ziram (5.421μgl-1), Zinc pyrithione (5.513μgl-1), Diuron (6.640μgl-1), Zineb (232.249μgl-1), Sea-nine 211(267.368μgl-1), Chlorothalonil (360.963μgl-1) and Dichlofluanid (377.010μgl-1) in 96h. In Artemia larvae, the biocides were evaluated the LC50 for larval survivals at 48h. Sea-nine 211 and Copper pyrithione were 0.318 and 0.319mgl-1. Chlorothalonil, Zinc pyrithione and Ziram were 2.683, 3.147 and 4.778mgl-1. Irgarol 1051, Diuron, Zineb and Dichlofluanid were 9.734, 30.573, 41.170 and 154.944mgl-1. These results provide baseline data concerning the toxicity of antifouling biocides against marine environment.

The study on changes of rectum area in proton prostate cancer therapy

The purpose of this study is to determine the changes in the rectum area during treatment and to identify the rectum area within the given field of view in order to reproduce the same pose as that presented during therapy planning to properly deliver the planned dose to the prostate. We obtained digitally reconstructed radiographs after planning treatment for 30 patients out of all patients who had been subjected to proton prostate cancer therapy from August 2012 to November 2014 at this hospital. We then obtained an image using a digital imaging positioning system (DIPS) on the first day of treatment. When planning the digitally reconstructed radiograph treatment, we determined the change in size of the rectum between the actual treatment and treatment planning by measuring the cross section of the rectum and the cross section on the image from the DIPS. The results indicated that the rectum area in the digitally reconstructed radiograph taken during treatment planning and the rectum area obtained from the DIPS image during treatment were different. As a consequence, when region targeted for proton treatment of prostate cancer does not maintain a constant volume, the position of the prostate does not receive an adequate dose due to such changes. Therefore, the results of this study will be useful to determine the corresponding volume during a prostate treatment plan.

Evaluation of antifouling system of new antifouling agents using spores of the green alga, Ulva pertusa and diatom, Nitzschia pungens1a

대형녹조류인 Ulva pertusa는 전 세계 연안에 서식하는 저서성 종으로 대발생 또는 인공구조물에 착생되어 경제적, 사회적인 측면에서 문제를 야기시키고 있다. 착생생물을 제어하기 위해 신방오제인 ziram, diruon, zinc pyrithione (ZnPT), copper pyrithione(CuPT), DBNPA, triclosan 등이 방오도료로 사용 중이나, 대형 및 미세조류를 이용한 신방오 제들의 방오능 검증과 기초적인 연구자료가 부족한 실정이다. 따라서 본 연구에서는 초기 우점착생종인 구멍갈파래의 포자를 이용하여 방오제의 효능을 검증하고 생체막 형성의 우점종인 미세조류 Nitzschia pungens를 이용한 방오능을 검증하였다. 구멍갈파래포자의 운동성 검증에서 ziram과 ZnPT는 diuron, CuPT, DBNPA, triclosan보다 50% 높은 운동성 억제를 나타내었고 착생 검증에서는 ziram이 가장 낮은 착생률 1%로 나타났으며 CuPT는 100 μg/L의 농도에서 다른 대조군에 비해 80%의 성장율 억제를 보였다. 본 연구의 결과로 신방오제의 방오능을 검증하여 향후 방오능 검증에 기초자료가 될 것으로 사료된다.

The Analysis of Proximate Composition, Minerals and Amino Acid Content of Red Alga Pyropia dentata by Cultivation Sites

In this study, the proximate composition of Pyropia dentata was compared by the analysis of minerals and amino acids that were produced at Seocheon, Chungcheongnam-do and at Wando and Jangheung, Jeollanam-do. Moisture, ash and crude proteins were analyzed using the AOAC method, and crude lipid was analyzed using the Soxhlet method, and inorganic analysis was performed using ICP-OES. Amino acid was used for the amino acid analyzer. The proximate composition analysis, moisture content, maximum values were displayed in Wando while the maximum content of ash appeared at Jangheungs Pyropia. Crude proteins was appeared at Seocheons Pyropia and the maximum amount of crude lipid, carbohydrate was appeared in Wandos Pyropia. Inorganic analysis, calcium, potassium, magnesium, sodium, phosphorus, cobalt, chromium, copper, iron, manganese, nickel, zinc were analyzed from the Seocheons Pyropia, however, cobalt, chromium, and nickel was not detected in Wandos Pyropia. For amino acid analysis, a total of 17 amino acids were detected: leucine, valine, aspartic acid, glutamic acid, and the amount of alanine accounted for about 57 % of total amino acids(26.1-28.7 %). The proximate composition, minerals, and amino acid of Pyropia dentata were different depending on the coastal ecological habitats.

Isolation of Pollutant (Pine Needle Ash)-Responding Genes from Tissues of the Seaweed Ulva Pertusa

Genetic responses of the seaweed Ulva pertusa to pine needle ash have been compared using differential display technique. The tissue viability was assessed to evaluate the stress level with triphenyltetrazolium chloride. Total RNA, from tissues treated in seawater containing ash, was reverse transcribed and amplified by PCR with arbitrary primers. The genetic fragments responding to the stress were selectively isolated from agarose gel and sequenced with a DNA auto sequencer. According to sequence analysis, an ash-inducible gene (342 bp) and an ash-suppressed gene (1690 bp) were identified as hypothetical proteins.

Antifouling properties of plasticizers BPBG and DNOP against algal spore and mussel attachment

Abstract Antifouling activities of butylphthalyl butylglycolate (BPBG) and di-n-octylphthalate (DNOP) were assayed on the attachment of spores of the green alga Enteromorpha prolifera and by the foot repulsive reaction of the mussel Mytilus edulis. The concentration of BPBG required to inhibit 50% attachment of algal spores (ID50) was 0.28 mM. The concentration of BPBG required to cause foot repulsion in 50% of mussels (RD50) was 0.64 mM. Concentrations of DNOP required for ID50 and RD50 were 0.09 mM and 0.08 mM, respectively. Therefore, both anthropogenic plasticizer compounds showed potent antifouling activities against algal spore and mussel attachment.