• 융합신호처리학회논문지
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• 제3권4호
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• pp.35-41
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• 2002

복잡한 문제들의 근사해를 구하기 위하여 최근 다양한 방법들이 소개되고 있다. 이러한 방법들은 주로 금속의 서랭(Annealing)에 의해 금속분자의 에너지가 최저점에 도달하는 과정을 모의실험한 최적화 기법(Simulated Annealing), 생물의 적자생존(Survival of Fittest)과정을 이용한 최적화 기법인 유전적 알고리즘(Genetic Algorithm)등 물리적 현상이나 생물 ?생명에 관련된 모의를 최적화 문제에 응용한 방법들이다. 최근에 소개된 Particle Swarm Optimization(PSO)는 주로 조류나 어류등의 생물의 무리가 각각의 개체가 가지고 있는 정보를 공유해가며 먹이를 찾아가는 과정을 모의한 기법이다. 하지만, 이 기법의 탐색과정이 명확하게 밝혀져 있지 않다. 본 논문에서는 PSO의 탐색과정을 가시화 하는 것을 목적으로 한다. 탐색과정을 가시화 하는 작업을 통해 그 탐색 능력을 시각적으로 파악하는 것이 가능하며 기법에 관한 이해를 돕고 교육적 효과도 기대 가능하다.

• Journal of Microbiology and Biotechnology
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• 제21권7호
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• pp.703-710
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• 2011

Enzymatic saccharification of corn stover using Phanerochaete chrysosporium and Gloeophyllum trabeum and subsequent fermentation of the saccharification products to ethanol by Saccharomyces cerevisiae and Escherichia coli K011 were achieved. Prior to simultaneous saccharification and fermentation (SSF) for ethanol production, solid-state fermentation was performed for four days on ground corn stover using either P. chrysosporium or G. trabeum to induce in situ cellulase production. During SSF with S. cerevisiae or E. coli, ethanol production was the highest on day 4 for all samples. For corn stover treated with P. chrysosporium, the conversion to ethanol was 2.29 g/100 g corn stover with S. cerevisiae as the fermenting organism, whereas for the sample inoculated with E. coli K011, the ethanol production was 4.14 g/100 g corn stover. Corn stover treated with G. trabeum showed a conversion 1.90 and 4.79 g/100 g corn stover with S. cerevisiae and E. coli K011 as the fermenting organisms, respectively. Other fermentation co-products, such as acetic acid and lactic acid, were also monitored. Acetic acid production ranged between 0.45 and 0.78 g/100 g corn stover, while no lactic acid production was detected throughout the 5 days of SSF. The results of our experiment suggest that it is possible to perform SSF of corn stover using P. chrysosporium, G. trabeum, S. cerevisiae and E. coli K011 for the production of fuel ethanol.

• Applied Biological Chemistry
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• 제11권
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• pp.109-117
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• 1969

분뇨처리장(糞尿處理場)에서 400여(餘) 균주(菌株)를 분리(分離)한 결과(結果) 그중(中) 두 균주(菌株)가 cellulase생성(生成)이 강(强)하였다. 이 균주(菌株)는 진탕배양(振湯培養)으로 cellulase를 많이 생성(生成)하였으며 이들 효소(酵素)의 성질(性質)은 다음과 같다. 1. 최적(最適) pH는 4.0에서 5.5 범위이다. 2. 안전(安全) pH는 3.5에서 6.5 범위이다. 3. 최적온도(最適溫度)는 $40^{\circ}C$에서 $45^{\circ}C$ 이다. 4. 열안전성(熱安全性)은 $50^{\circ}C$ 이하이며 $70^{\circ}C$에서 거의 불활성화(不活性化) 된다. 5. 투석효소(透析酵素)는 $Mn^{2+}\;Co^{2+}$로 활성화되며 $Hg^{2+}$는 강한 조해제(阻害劑)이다.

• 한국수산과학회지
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• 제54권4호
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• pp.388-396
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• 2021

Antimicrobial resistance patterns of Escherichia coli were investigated. Strains were isolated from 310 shellfish, 36 crustaceans, and 12 fish collected off the West Coast of Korea from April 2019 to October 2020. Two hundred and ninety-five E. coli strains were isolated from shellfish, 100 from crustaceans, and 54 from fish. Strains isolated from shellfish showed the highest resistance to ampicillin (27.5%), whereas those from crustaceans were resistant to sulfisoxazole (30.0%) and those from fish were resistant to ampicillin (59.3%) and sulfisoxazole (59.3%). Ceftazidime resistance was observed in strains isolated from short neck and hard clams, whereas gentamicin resistance was observed in strains from fish. Multi-drug resistance was observed in 56 strains (48.7%) isolated from shellfish, 11 (28.2%) from crustaceans and 27 (73.0%) from fish. Depending on the source of isolation, the strains showed specific antimicrobial resistance tendency. Strains isolated from shellfish showed 12 different multi-drug resistance patterns, whereas those from crustaceans showed high resistance (59%) to a single antimicrobial agent and those from fish showed a broad trend of multi-drug resistance to more than eight antimicrobials.

• Journal of Microbiology and Biotechnology
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• 제31권4호
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• pp.584-591
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• 2021

Marine algae (seaweed) encompass numerous groups of multicellular organisms with various shapes, sizes, and colors, and serve as important sources of natural bioactive substances. The brown alga Ecklonia cava Kjellman, an edible seaweed, contains many bioactives such as phlorotannins and fucoidans. Here, we evaluated the antioxidative, neuroprotective, and anti-apoptotic effects of E. cava extract (ECE), E. cava phlorotannin-rich extract (ECPE), and the phlorotannin dieckol on neuronal PC-12 cells. The antioxidant capacities of ECPE and ECE were 1,711.5 and 1,050.4 mg vitamin C equivalents/g in the ABTS assay and 704.0 and 474.6 mg vitamin C equivalents/g in the DPPH assay, respectively. The dieckol content of ECPE (58.99 mg/g) was approximately 60% higher than that of ECE (36.97 mg/g). Treatment of PC-12 cells with ECPE and ECE increased cell viability in a dose-dependent manner. Intracellular oxidative stress in PC-12 cells due to ECPE and ECE decreased dose-independently by up to 63% and 47%, respectively, compared with the stress control (323%). ECPE reduced the production of the pro-apoptotic proteins Bax and caspase-3 more effectively than ECE. Early and late apoptosis in PC-12 cells were more effectively decreased by ECPE than ECE treatments. From the results obtained in this study, we concluded that ECPE, which is rich in phlorotannins, including the marker compound dieckol, may be applied to the development of functional materials for improving cognition and memory.

• 한국환경농학회지
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• 제37권4호
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• pp.324-332
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• 2018

곤충은 변온동물로 육지생태계에서 주로 서식하면서, 식물의 생체량 조절, 종다양성 유지에 중요한 역할을 한다. 주변온도는 변온동물인 곤충의 생리적 반응속도, 뿐만 아니라 생존과 분포를 결정하며, 기후변화에 영향을 준다. 본 연구는 높은 온도에서 곤충의 적응성에 관련있는 유전자를 전사체를 이용하여 동정하였다. 고온에서 사육된 배추좀나방 유충의 지방체로부터 차세대 염기서열 분석법을 이용하여 전사체를 확보하였다. 대사중심인 지방체에서 구조단백질, 열충격단백질, 항산화단백질, 해독효소 들이 동정되었다. 이들 중에서 표피단백질(표피단백질, 키틴합성효소, 엑틴, 카이틴 합성), 스트레스관련단백질(시토크롬 P450), 열충격단백질, 한산화단백질은 발현이 증가되었으나, glutathione S transferase 발현은 오히려 감소되었다. 이상의 결과는 기후변화의 주요인인 온난화에 대한 해충의 생리적 대응과 온도적응을 이해하는데 필요한 기초자료를 제시한다.

• 한국환경농학회지
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• 제40권1호
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• pp.1-12
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• 2021

BACKGROUND: G protein-coupled receptors (GPCRs) are widely distributed in various organisms. Insect GPCRs shown as in vertebrate GPCRs are membrane receptors that coordinate or involve in various physiological processes such as learning/memory, development, locomotion, circadian rhythm, reproduction, etc. This study aimed to identify GPCRs expressed in fat body and compare the expression pattern of GPCRs in different temperature conditions. METHODS AND RESULTS: To identify GPCRs genes and compare their expression in different temperature conditions, total RNAs of fat body in Plutella xylostella larva were extracted and the transcriptomes have been analyzed via next generation sequencing method. From the fat body transcriptomes, genes that belong to GPCR Family A, B, and F were identified such as opsin, gonadotropin-releasing hormone receptor, neuropeptide F (NPF) receptor, muthuselah (Mth), diuretic hormone receptor, frizzled, etc. Under low temperature, expressions of GPCRs such as C-C chemokine receptor (CCR), opsin, prolactin-releasing peptide receptor, substance K receptor, Mth-like receptor, diuretic hormone receptor, frizzled and stan were higher than those at 25℃. They are involved in immunity, feeding, movement, odorant recognition, diuresis, and development. In contrast to the control (25℃), at high temperature GPCRs including CCR, gonadotropin-releasing hormone receptor, moody, NPF receptor, neuropeptide B1 receptor, frizzled and stan revealed higher expression whose biological functions are related to immunity, blood-brain barrier formation, feeding, learning, and reproduction. CONCLUSION: Transcriptome of fat body can provide understanding the pools of GPCRs. Identifications of fat body GPCRs may contribute to develop new targets for the control of insect pests.

• 공업화학
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• 제33권6호
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• pp.557-562
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• 2022

Hyaluronic acid (HA) is a mucopolysaccharide, occurring naturally in living organisms. It is one of the most hydrophilic molecules, so it has been known as being related to skin hydration and skin aging. The purpose of this study was to examine the effects of Cimicifuga heracleifolia ethanol extract on the hyaluronic acid synthesis and the inhibition of hyaluronidase activity. To determine cytotoxicity, hyaluronic acid synthase 2 (HAS2) gene expression, HA production and, hyaluronidase inhibitory effects, 3-(4,5-dimethylthiazol-2-ly)-2,5-diphenyl tetrazolium bromide (MTT) assay, real time - polymerase chain reaction (RT-PCR), hyaluronic acid enzyme linked immunosorbent assay (HA-ELISA), and hyaluronidase assay were used, respectively. When the Cimicifuga heracleifolia extract was treated in the HaCaT cells up to 500 ㎍/mL concentration, cytotoxicity was confirmed by the Cimicifuga heracleifolia extract at concentrations above 200 ㎍/mL. Therefore, the optimum concentration of all experiments used in this study was determined to be 200 ㎍/mL. HAS2 gene expression increased by Cimicifuga heracleifolia extract in a concentration-dependent manner at all treatment concentrations. The production rate of HA was tended to decrease at the highest concentration of 200 ㎍/mL. The hyaluronidase activity inhibition effect of Cimicifuga heracleifolia extract was very high compared to the control group. Based on these results, Cimicifuga heracleifolia extract was expected to have a moisturizing effect on human skin and special attention should be paid to the determination of the concentration of Cimicifuga heracleifolia when developing cosmetic materials using it.

• Journal of Ecology and Environment
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• 제46권4호
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• pp.304-315
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• 2022

Background: Filter-feeding zooplankton has limited food resources owing to their habitat. Consequently, it is crucial for them to acquire all essential compounds, such as fatty acids (FAs) and amino acids, from confined diets. To elucidate the trophic transfer of FAs to filter feeders, the primary consumers in freshwater ecosystems, we compared the FA accumulation patterns of two species of filter-feeding zooplankton, Daphnia magna and Branchinella kugenumaensis, in a laboratory experiment. Experimental neonates and nauplii preyed on a single phytoplankton species (Selenastrum capricornutum) for three days after hatching prior to diet switching. Five replicates per feeding group in each species were fed on six different types of mixed phytoplankton diet for 10 days after diet switching. Subsequently, the consumers and diets were harvested and FAs were extracted. Results: Principal component analysis showed that the FA profiles of zooplankton were well-grouped by species and diet. Although diet affects the FA profiles of consumers, they exhibit different FA accumulation patterns. D. magna had a higher 18C-ω3 content and ω3/ω6 ratio than did B. kugenumaensis. In contrast, B. kugenumaensis had higher contents of 18:1ω7 and 20:5ω3 (eicosapentaenoic acid), 22:6ω3 (docosahexaenoic acid), and a higher ratio of ∑18C monounsaturated FAs to ∑18C-ω3 polyunsaturated FAs than did D. magna. Conclusions: This study showed that two primary consumers, D. magna and B. kugenumaensis, fed the same diet had different assimilation patterns of FAs under controlled environments. Specific FA accumulation patterns in filter feeders can provide information on the transfer process of various FAs to high-trophic organisms.

• 한국해양생명과학회지
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• 제7권2호
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• pp.61-73
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• 2022

안정동위원소 분석 기법(Stable isotope analysis, SIA)은 환경과학, 생태학, 지구생물화학, 법의학, 고고학 등 다양한 연구 분야에 활용되고 있다. 본 총설에서는 수산 및 양식 연구에 안정동위원소 비 분석 기법을 활용하기 위해 필요한 배경 지식을 소개하고자 한다. 특히, 자연값(natural abundance)을 이용하는 연구에 초점을 두었고 원소가 생물의 조직으로 통합되는 과정에서 발생하는 분별작용(동위원소 비의 변화)에 대한 원리와 안정동위원소 비가 유용한 도구로서 어떤 목적으로 생태, 환경학 분야에 이용되는지, 나아가 수산 및 양식 분야에 활용 가능한 예들을 제시하고자 한다. 본 논문을 통한 안정동위원소 분야의 이해로 향후 수산학 및 양식 연구에서 안정 동위원소 비의 다양한 활용이 기대된다.