본 독도 연안 해역에서 2019년 계절적 수환경 특성과 식물플랑크톤 군집구조 변화 특성을 파악하고, 2018년 과 2019년 특성을 비교하고자 두 연도의 4계절 수층별 조사가 수행되었다. 2019년에는 총 4문 69종의 식물플랑크톤이 관찰되었고, 평균 식물플랑크톤 개체수는 1.90×104 cells L-1로 매우 낮게 나타났다. 동계에는 평균 3.19×104 cells L-1로 대부분 미동정 편모류가 우점하였고, 춘계에는 3.12×104 cells L-1로 역시 편모류가 약 50%를 차지하였으며, P. obtusidens를 포함한 다양한 와편모조류가 출현한 특징이 있었다. 하계 개체수는 0.46×104 cells L-1로 매우 낮은 개체수와 종이 나타났고, 추계에는 평균 개체수가 0.89×104 cells L-1로 낮았으며, 여러 종의 Chaetoceros와 함께 Bacteriastrum spp., Guinardia striata, Psuedo-nitzschia spp. 과 같은 규조류가 다양하게 나타났다. 또한, 2018년 추계와 동일하게 열대 지표종인 Ornithocercus sp.와 Amphisolenia sp.가 관찰되었다. 2019년에는 대마난류와 남해 연안의 영향을 받은 종이 출현하였지만, 전반적으로 매우 낮은 개체수를 보이며 편모조류가 우점한 특징이 있었다. 식물플랑크톤 다양성은 2018년 하계와 2019년 동계에 높게 나타났고, 군집분석에서도 계절에 상관없이 크게 4개 그룹으로 구분되었다. 2018년과 2019년 수환경은 특이적으로 춘계에 성층이 약하게 형성되었고, 2018년 추계에는 하계와 동일하게 수괴가 안정되어 식물플랑크톤이 대증식한 것으로 사료된다. 식물플랑크톤 군집 및 개체수는 하계를 제외하고 계절별 우점 종의 차이를 보였으며, 이차이는 추계에 가장 뚜렷하였다. 따라서 독도 연안 해역은 일반적인 동해의 특성과는 다르게, 외해역임에도 불구하고 얕은 지형과 다양한 해류, 섬효과 등과 같은 복합적인 영향으로 연도별 계절별 특성이 다르게 나타날 수 있다는 것을 시사한다.

To investigate the characteristics of seasonal environment and phytoplankton community structure in the coastal area of Dokdo, a survey of Dokdo around waters was conducted during the four seasons. Phytoplankton of 4 phylum 72 species in four seasons were collected in Dokdo around water. The seasonal mean abundance of phytoplankton were 3.32×104 cells L-1 in winter, 1.04×104 cells L-1 in spring, 0.28×104 cells L-1 in summer, and 4.86×104 cells L-1 in autumn in Dokdo around water. During winter, the diatoms Chaetoceros spp. had dominated. During spring, when the nutrients in the euphotic layer were depleted, the nano-flagellates and Cryptomonas appeared at surface layer. In summer, the abundance of phytoplankton was relatively low, which lead to occurrence of diatoms such as genus of Chaetoceros, Rhizosolenia, and Skeletonema. In autumn, Pseudo-nitzschia spp. was the most dominant species and tropical species such as Amphisolenia sp. and Ornithocercus magnificus were observed, implying that they may have introduced within warm water current such as Kurosiwo Current. Therefore, although natural phytoplankton communities in the vicinity water of Dokdo are mainly influenced by Tsushima Warm Current branched Kurosiwo Current, their population dynamics was affected on the spatio-temporal change of physicochemical factors by short-term wind events, namely “island effect”. Long-term survey research is needed to facilitate food-web response in marine ecosystem associated with phytoplankton biomass and physicochemical factors including the warm water current in oligotrophic offshore water of Dokdo, which may have significant role for sustainable use of Dokdo.

본 연구에서는 강풍에 의한 연안 용승 및 섬효과를 구체적으로 파악하기 위해서 춘계 강한 저기압 통과 전후를 대상으로 위성자료, 해양환경 및 물리적인 수직 구조와 함께 식물플랑크톤의 군집구조를 파악하였다. 5월 3일 강한 저기압이 통과하면서 남풍계열의 바람이 우점하였고, 10일 정도의 시간차를 둔 5월 12일에는 동한난류가 이동한 경로주 변해역에서 높은 엽록소값이 관찰되었다. 식물플랑크톤 수평적 군집조성은 동한난류의 영향을 강하게 받은 울진 연안과 울릉도 사이의 정점에서는 규조류가 극히 높은 밀도로 우점하였고, 상대적으로 외양인 울릉도와 독도 섬주변에서는 섬효과에 의하여 침편조류 H. akashiwo가 높은 개체수를 유지하였다. 엽록소의 수직적 분포는 울진에서 울릉도로 이어지는 정점에서 엽록소 아표층극대 (Sub-surface Chl-a Maximum)가 20 m 층에서 관찰되었고, 울릉도와 독도 섬주 변의 대부분 정점에서는 30~40 m 층까지 전 수층에 걸쳐 균일하게 높은 엽록소 형광값이 관찰되었다. 이는 섬효과에 의하여, 강한 수층혼합이 일어난 것을 의미하고, 그 결과 유광층 상부에 공급된 영양염류에 의하여 식물플랑톤이 대발생하였다. 결과적으로 춘계 한반도 남동해역 (울진-울릉도-독도) 에서는 남풍계열의 바람이 우점하면, 연안 용승이 발생할 수 있고, 이는 식물플랑크톤의 대발생에 중요한 역할을 하는 것 으로 관찰되었다. 아울러, 동해 연안해역에서 기인된 식물플 랑크톤은 동해 중앙 및 남서해역으로 공간이동하면서 울릉도-독도의 섬효과와 함께 동한난류의 사행, 소용돌이의 발달 등에 따라서 종조성이 다르게 나타날 가능성을 시사하였다.

The effects of β-lapachone on gastric secretion were investigated. The pylorus of male Sprague-Dawley rats was ligated and intraduodenally injected with β-lapachone, and the volume, pH, free HCl, and total acidity of gastric fluid were measured 6 hours after the operation. Treatment with β-lapachone resulted in dose-dependent inhibition of gastric secretion Gastric fluid was reduced to 42.9% of control level by 100 mg/kg of β-lapachone, leading to an increase of pH to 6.70 from 1.85 in the control group. In parallel with the increase of pH, at this dosage, free HCl and total acidity decreased to 16.7% and 12.0%, respectively, of control levels. β-Lapachone exhibited ED50 values of 72, 46, and 47 mg/kg for inhibition of gastric volume, free HCl, and total acidity, respectively, implying a superior efficacy on gastric acid to volume. In comparison, pantoprazole (30 mg/kg) reduced the volume, free HCl and total acidity of gastric fluid to 53.0%, 26.0%, and 25.0%, respectively, of control levels, resulting in an increase in pH to 6.36. In the current study, it was confirmed that β-lapachone at an appropriate dose (100 mg/kg) exerted a higher inhibitory effect on gastric secretion than pantoprazole (30 mg/kg), a well-known proton-pump inhibitor. Therefore, it is suggested that β-lapachone could be a candidate compound for prevention or treatment of gastric ulcers induced by diverse psychological and physical stimuli.

This study was conducted in order to evaluate the effect of sericin-calcium (SC) as therapy for ovariectomy-induced osteoporosis in rats. Three weeks after ovariectomy (OVX), Sprague-Dawley rats were divided randomly into three groups: sham-operated group (Sham), ovariectomized group, and SC-treatment group (OVX+SC). Rats in the OVX+SC group were given drinking water containing 0.07% SC for eight weeks. Bone breaking force, mineralization, and blood parameters related to bone metabolism were analyzed. In OVX animals, blood concentration of 17β-estradiol showed a significant decrease, while osteocalcin and type I collagen C-terminal telopeptides (CTx) showed an increase. Breaking force of femurs as well as bone mineral density (BMD), ash, calcium, and phosphorus in femurs showed a significant decrease following OVX. Treatment with SC (0.07% in drinking water) resulted not only in remarkable restoration of the decreased 17β-estradiol and increased osteocalcin and CTx concentrations, but also led to recovery of decreased femoral breaking force, BMD, ash, calcium, and phosphorus. It is suggested that SC effectively improves bone density by preventing bone turnover-mediated osteocalcin, CTx, and minerals, and that it could be a potential candidate for use in therapy or prevention of post-menopausal osteoporosis.

Effects of carnitine on atherosclerosis and steatosis of hypercholesterolemic rabbits induced by a high-cholesterol diet (HCD) containing 0.5% cholesterol and 2.0% corn oil were investigated. Male New Zealand white rabbits with hypercholesterolemia (blood cholesterol 1,000-1,500 mg/dl) induced by two-week feeding a HCD, were fed a HCD containing 0.008 or 0.075% L-carnitine for an additional eight weeks. Feeding a HCD for 10 weeks resulted in severe atheromatous change, covering 55.7% of the aortic walls, in addition to profound hepatic steatosis. However, carnitine supplementation resulted in recovery of the increased low-density lipoproteins and triglycerides and a decrease in the levels of high-density lipoproteins following HCD feeding, although the increased cholesterol concentration was not potentially attenuated. Notably, carnitine induced a marked reduction of the atheroma area and hepatic lipid accumulation as well as lipid peroxidation. The results of this study indicated that carnitine exerted anti-atherosclerotic and fatty liver-preventing activities through blockade of lipid peroxidation and regulation of lipid metabolism.

The effects of isotonic saline on corneal penetration, thickness, and injury, as well as lacrimal secretion in a rat model of dry eye were investigated, in comparison with distilled water. Male Sprague-Dawley rats received intraperitoneal administration of atropine sulfate (20 mg/kg) and their eyes were exposed to dry (relative humidity 25-35%) air flow (2.4 m/sec), under Zoletil anesthesia, for 5 hr to induce dry eye. During the period of dry eye induction, distilled water or isotonic saline (5 μl) was instillated onto the cornea every 30 min. Corneal penetration was measured through fluorescein dye quantification, and corneal thickness and injury were examined under a microscope. Lacrimal (tear) secretion and mucin-like glyocoprotein excretion from goblet cells were measured using the Schirmer test and microscopy, respectively. In dry eye rats treated with distilled water, corneal thickness, tear secretion, and mucin-like glycoprotein excretion were decreased to 74.0%, 74.1%, and 46.3% of normal levels, respectively, resulting in marked corneal injury and a significant increase in corneal penetration. In comparison, treatment with isotonic saline resulted in recovery of lacrimal secretion, in spite of a slight improvement of mucin-like glycoprotein excretion, and thereby prevented corneal penetration of fluorescein by 10%. The results indicate that repeated instillation of isotonic saline could provide slightly greater protection from corneal injury, compared with distilled water by facilitating lacrimal secretion, in addition to relief of inconvenience and pain.

This study was conducted in order to investigate repeated-dose toxicities of Magnolia ovobata ethanol extract (MEE). MEE was administered orally to male and female Sprague Dawley rats at dose levels of 0, 500, 1,000, or 2,000 mg/kg for four weeks. Repeated administration of MEE did not induce abnormalities in general signs, body weight gain, feed and water consumption, necropsy findings, or organ weights. In addition, no abnormality was observed in hematological analyses; red blood cells and their indices, white blood cells, platelets, and coagulation times. In male rats, BUN and creatinine showed an increase at doses of 2,000 mg/kg and 500-1,000 mg/kg, respectively, while in female rats, lactate dehydrogenase and creatine phosphokinase showed a decrease at 2,000 mg/kg, the upper-limit dose of repeated-dose toxicity studies. However, there were no dose-dependent increases or gender-relationship. In addition, other parameters of the hepatic and muscular toxicities as well as energy and lipid metabolism were not affected. In microscopic examination, no considerable pathological findings were observed. The results indicate the safety of oral administration of MEE to the upper-limit dose.

Effects of Vegemil® containing soybean proteins and isoflavones on the growth and bone density of broiler chickens were investigated. One-week-old male and female Arbor Acres broiler chickens were fed on Vegemil® A containing 3% soybean proteins and 162 ppm isoflavones, instead of water, for 30 days and their growth indices (body weight, leg weight and femur length) and bone density were analyzed. The body weight gains in male and female chickens were increased by 15.6% and 31.7%, respectively, following feeding Vegemil® A compared to normal water. Vegemil® A increased leg weight as well as femur length of females by 22.9% and 15.0%, respectively. In addition, Vegemil® A feeding enhanced femoral bone density by 21.3% in comparison with water feeding. Therefore, it is suggested that Vegemil® A not only facilitates body growth, but also strengthens bone density of normal chickens, and that it could be a promising candidate for the improvement of infant growth and for the prevention of menopausal osteoporosis.

The present study was carried out to establish an animal model, displaying long-term learning and memory dysfunction, since single intracerebroventricular (icv) injection of amyloid β peptide (Aβ) causes a short-term memory impairment. Male ICR mice were fed a high-cholesterol diet (HCD) containing 3% cholesterol, 1% corn oil and 0.5% cholic acid, and 1 week later, icv injected with Aβ_1-42 (5 μg/head). Learning/ memory function was assessed via passive avoidance performances 1 day and 2, 4, and 6 weeks after Aβ_1-42 injection, in addition to blood biochemical analyses for lipid profiles and hepatic function. Total cholesterol, lowdensity lipoproteins and hepatic dysfunction parameters markedly increased, while high-density lipoproteins were reduced following HCD feeding. Whereas single injection of Aβ induced temporary memory loss 1 day after administration, exhibiting full recovery after 2 weeks, Aβ treatment in combination with HCD feeding lasted the learning/memory impairment up to 6 weeks. Therefore, it is suggested that hypercholesterolemia augments Aβ-induced memory loss, and that Aβ injection plus HCD feeding could be a long-term memorydeficit model suitable for long-term treatment with drugs or stem cells.

The Maillard Reaction Products (MRPs) such as Glucose-tyrosine (Glu-Tyr) and Xylose-arginine (Xyl-Arg) have antioxidant, antimutagenic, and antibacterial effects. However, to date, still little is known about the other biological effects of the MRPs. In this study, we investigated whether the fructose-tyrosine MRP, 2,4-bis(p-hydroxyphenyl)-2-butenal (Fru-Tyr), could modulate cell cycle progression and NF-κB activity, and thereby induce apoptotic cell death of colon cancer cells. Treatment with different concentrations (10-40 μg/ ml) of Fru-Tyr for 24 h inhibited colon cancer cell (SW620 and HCT116) growth followed by induction of G₂/M phase cell cycle arrest and apoptosis in a dose-dependent manner. We also found that Fru-Tyr suppressed tumor necrosis factor-alpha (TNF-α)-induced NF-κB transcriptional activity. Moreover, Fru-Tyr induced the expression of apoptotic gene, cleaved caspse-3. These results suggest that Fru-Tyr inhibited colon cancer cell growth through induction of G₂/M phase cell cycle arrest and apoptotic cell death by modulating of NF-κB.

Four-week repeated-dose toxicity of Misaengtang (MST) was evaluated according to Toxicity Test Guideline of Korea Food and Drug Administration using 6-week-old Sprague-Dawley rats. Based on the results of preliminary single-dose toxicity study, confirming safety up to an upper-limit dose, MST was dissolved in drinking water and orally administered at doses of 500, 1,000, or 2,000 mg/kg for 28 days. All doses including the upper-limit limited dose (2,000 mg/kg) of MST did not cause any abnormalities of rats, including mortality, clinical signs, body weight gain, feed/water consumption, necropsy findings, organ weights, hematology and blood biochemistry. Rather, high doses (1,000-2,000 mg/kg) of MST reduced the serum levels of alanine transaminase, aspartate transaminase, creatinine phosphokinase, lactate dehydrogenase and triglycerides, in addition to an increase in glucose, indicative of protective effects on hepatic and muscular injuries. Both maximum-tolerable dose and no-observed-adverse-effect level were not determined. The results indicate that long-term intake of high-dose MST might not induce general adverse-effects.

We tested the effects of roasted and non-roasted Zizyphi Spinosi Semen (ZSS) hot water extracts on pentobarbital-induced sleeping behavior, pentylentetrazole-induced convulsions, and locomotor activity in mice. Both ZSS extracts decreased locomotor activity and pentylentetrazole-induced convulsions. Both extracts alos dose-dependently shortened the sleep onset and prolonged the sleep time induced by pentobarbital, with roasted extract being more potent. In addition, chemical constituents in HPLC also were different. Thus, both roasted and non-roasted ZSS extracts potentiate the sleep onset and the sleeping time induced by pentobarbital, decrease locomotor activity, and reduce pentylentetrazole-induced convulsions, with roasting improving extract potency.

Anti-inflammatory effects of ethanolic extract of Angelica gigas (EAG 50, 150, and 500 mg/kg) were investigated in thermal burn-paw edema model. Immersion of rat hind legs into 48.5℃ water for 50 scincreased the leg volume by 0.46-0.55 ml. EAG attenuated not only the paw volume in a dose-dependent manner, but also blood lymphocyte counts and interleukin-6 level increased by burns, without influence on the level of tumor-necrosis factor-α. Moreover, EAG reduced alkaline phosphatase level, a parameter of hepatic injury, which was increased by thermal burns. The results indicate that EAG attenuates inflammatory aymptoms induced by thermal burn and EAG or its conmarin derivatives could be a promising anti-inflammatory drug candidate in inflammation diseases.