• Asian-Australasian Journal of Animal Sciences
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• 제7권3호
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• pp.303-316
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• 1994

Microbial digestion of feed in the rumen involves a sequential attack culminating in the formation of fermentation products and microbial cells that can be utilized by the host animal. Most feeds are protected by a cuticular layer which is in effect a microbial barrier that must be penetrated or circumvented for digestion to proceed. Microorganisms gain access to digestible inner plant tissues through damage to the cuticle, or via natural cell openings (e.g., stomata) and commence digestion from within the feed particles. Primary colonizing bacteria adhere to specific substrates, divide to form sister cells and the resultant microcolonies release soluble substrates which attract additional microorganisms to the digestion site. These newly attracted microorganisms associate with primary colonizers to form complex multi-species consortia. Within the consortia, microorganisms combine their metabolic activities to produce the diversity of enzymes required to digest complex substrates (e.g., cellulose, starch, protein) which comprise plant tissues. Feed characteristics that inhibit the microbial processes of penetration, colonization and consortia formation can have a profound effect on the rate and extent of feed digestion in the rumen. Strategies such as feed processing or plant breeding which are aimed at manipulating feed digestion must be based on an understanding of these basic microbial processes and their concerted roles in feed digestion in the rumen.

• Asian-Australasian Journal of Animal Sciences
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• 제23권6호
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• pp.742-749
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• 2010

We investigated the antioxidant efficacy of quercetin (0% Diet 1, 0.25% Diet 2, and 0.5% Diet 3) pretreatment for 30 and 60 days in response to cadmium (Cd) toxicity in the olive flounder, and measured the plasma lysozyme activity to understand the immune effects of quercetin. The lysozyme activity with Diets 2 and 3 was higher than with Diet 1. Based on this result, to examine the immune ability and antioxidant role of quercetin, we exposed olive flounder fed quercetin to Cd and then measured the expression and activity of antioxidant enzymes (superoxide dismutase (SOD) and catalase (CAT)) and lipid peroxidation (LPO). With Diets 2 and 3, the expression and activity of antioxidant enzymes and the $H_2O_2$ concentration were lower than with Diet 1. In addition, the LPO levels were lower than with Diet 1, which protected the cell membrane. Therefore, quercetin removed the reactive oxygen species (ROS) produced by Cd, indicating that quercetin has antioxidant ability. In addition to its antioxidant ability, quercetin has immune effects.

• ALGAE
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• 제25권1호
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• pp.17-26
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• 2010

The effects of salinity on various ecophysiological parameters of Ulva pertusa such as growth, nutrient uptake, photosynthetic performance and internal nutrient composition were tested. U. pertusa was collected from an eelgrass bed in a semi-protected embayment on the southwest coast of Korea. Under salinity regimes from 5 to 40 psu, the specific growth rates $(\mu)$ of U. pertusa ranged from 0.019 to $0.032\;d^{-1}$. Maximum growth rate was observed at 20 psu, and minimum at 40 psu. This species showed various uptake rates for nitrate and phosphate. Nutrient uptake was noticeably higher at intermediate salinity levels, and lower at both extremes. Salinity significantly influenced chlorophyll-$\alpha$ content and effective quantum yield. Tissue nitrogen content ranged from 1.5 to 2.9% N (dry weight), whereas tissue phosphorus ranged from 0.1 to 0.14% P (dry weight). The N : P ratio in the tissue of U. pertusa was considerably higher, ranging from 30 to 50. Increased growth at lower salinity suggests that the initial growth rate of U. pertusa is greater during the rainy season (i.e., late spring and early summer) than any other season during the year. The appearance of an Ulva bloom in eelgrass beds may be triggered by salinity more than by other environmental factors such as light and temperature.

• Natural Product Sciences
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• 제15권1호
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• pp.32-36
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• 2009

Glutamate causes neurotoxicity through formation of reactive oxygen species and activation of mitogen-activated protein kinase (MAPK) pathways. MAPK phosphatase-1 (MKP-1) is one of the phosphatases responsible for dephosphorylation/deactivation of three MAPK families: the extracellular signal-regulated kinase-1/2 (ERK-1/2), the c-Jun N-terminal kinase-1/2 (JNK-1/2), and the p38 MAPK. In this report, the potential involvement of MKP-1 in neuroprotective effects of curcumin, the active ingredient of turmeric (Curcuma longa), was examined using HT22 cells. Glutamate caused cell death and activation of ERK-1/2 but not p38 MAPK or JNK-1/2. Blockage of ERK-1/2 by its inhibitor protected HT22 cells against glutamate-induced toxicity. Curcumin attenuated glutamate-induced cell death and ERK-1/2 activation. Interestingly, curcumin induced MKP-1 activation. In HT22 cells transiently transfected with small interfering RNA against MKP-1, curcumin failed to inhibit glutamate-induced ERK-1/2 activation and to protect HT22 cells from glutamate-induced toxicity. These results suggest that curcumin can attenuate glutamate-induced neurotoxicity by activating MKP-1 which acts as the negative regulator of ERK-1/2. This novel pathway may contribute to and explain at least one of the neuroprotective actions of curcumin.

• 한국약용작물학회지
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• 제17권1호
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• pp.8-14
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• 2009

Pueraria lobata (Willd.) Ohwi was investigated to check its modulatory effects on the activation of macrophages upon inflammatory conditions treatment. For this purpose, we examined several inflammatory responses such as nitric oxide (NO) production, reactive oxygen species (ROS) generation, cytoprotection and phagocytosis under the treatment of methanol extract from P. lobata (Pl-ME). Pl-ME dose-dependently blocked NO production in lipopolysaccharide (LPS)- stimulated RAW264.7 cells but not sodium prusside (SNP)-generated NO release. The NO inhibition seemed to be due to blocking inducible NO synthase (iNOS), since Pl-ME suppressed its expression in a NF-${\kappa}B$-independent manner. Similarly, this extract also effectively protected RAW264.7 cells from LPS-induced cytotoxicity. However, Pl-ME did not block ROS generation and rather it enhanced. Finally, this extract negatively modulated FITC-dextran uptake. Therefore, our data suggested that Pl-ME may be involved in negatively regulating some macrophage-mediated inflammatory responses such as NO production and phagocytic uptake.

• 환경영향평가
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• 제22권3호
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• pp.265-276
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• 2013

This study assessed documentation status of each environmental assessment items by analyzing the 243 case of marine EIS on the Consultation System of Sea Area Utilization. Observed rate of tidal elevation, current, temperature, salinity in maine environment were below 20%. The EFDC tool is applied substantially in hydrodynamic modeling. The verification process, however, is very insufficient using the recent observed data. Also, in-situ assessment rate of pelagic organism such as phytoplankton was below 50%, and assessment for Chlorophyll a was not accomplished. Ecological index evaluation for zooplankton and benthic ecosystem were not considered in statements. Especially, the rational assessment on the fisheries resources and protected species were very limited. It was necessary that the core assessment items (checklists) were established for environmental scoping. Furthermore, suggestion of information related to development, regional coastal management plan, aquaculture farms, and facilities were enhanced. The redundancy problem of proceedings between Environmental Impact Assessment and Sea Area Utilization Assessment System was improved.

• 한국환경생태학회지
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• 제21권2호
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• pp.176-185
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• 2007

본 연구는 한국의 전체(울릉도와 제주도를 제외)를 대상으로 복분자딸기 군락의 자생지 조사를 수행한 결과이다. 복분자딸기의 전형적인 자생지에 24개 방형구를 선정하여 조사한 결과, 식생지 유형은 사면 노방지, 2차 천이지, 사면 훼손지, 엄정 보호지 및 가혹한 환경지 등으로 조사되었다. 복분자딸기 자생지 일대의 소산식물상은 71과 155속 18변종 1품종 199종 총 218분류군으로 나타났으며 그 가운데 80.74%가 다년생 식물로 나타났고 국화과 식물이 7.80%로 출현빈도가 가장 높았다.

• Journal of Ecology and Environment
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• 제42권1호
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• pp.43-49
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• 2018

Iris laevigata is geographically restricted and legally protected in Korea. In this study, a mesocosm study was conducted to examine the effects of environmental conditions such as water levels and soil nutrient conditions on the growth and survival of I. laevigata seedlings. Complete submergence lowered the total number of leaves, biomass, and survival rates. A rise in soil nutrients increased overall seedling growth and increased tiller numbers via the promotion of asexual reproduction. Also, we found that the lowest measured values of seedlings are associated with the most stressful condition due to the interaction of low soil nutrients and high water levels. I. laevigata seedlings, however, are distributed in low-nutrient habitats such as floating mat, even though they do not grow well under these conditions. This study suggests that I. laevigata does not prefer low-nutrient condition but choose another benefit such as low competition. Also, the water level must be lower than the seedling height for effective growth and management of I. laevigata.

• Journal of Advanced Marine Engineering and Technology
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• 제40권10호
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• pp.883-887
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• 2016

This study aims to evaluate the corrosion behavior of a newly developed high-strength steel in marine environments. Metals used in seawater are easily deteriorated because of the presence of corrosive species such as chloride ions in it. Seawater causes much higher corrosion than fresh water. Thus, the corrosion of steel in marine environment has been recognized as a crucial problem in designing structures which cannot be cathodically protected. In this study, the corrosion resistance of a newly developed high-strength steel was evaluated. Four different specimens were tested to confirm the corrosion resistance. The exposure corrosion test was carried out by exposing the specimens to different marine environments such as atmospheric, tidal, splash, and submerged zones for two years. The specimens taken out from each location were cleaned ultrasonically and chemically prior to the evaluation of their corrosion resistance by the weight loss method. Finally, the pitting depth of the specimens was also measured to evaluate their pitting corrosion. The conditions used for the corrosion test were similar to the environmental conditions. The corrosion test results revealed that the corrosion rate and pitting corrosion of the newly developed high-strength steel was lower than that of the other carbon steels.

• 한국식품저장유통학회지
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• 제18권6호
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• pp.967-972
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• 2011

Assai 열매추출물의 자유 라디칼 소거능을 측정하기 위하여 DPPH를 이용한 자유 라디칼 소거능 실험을 수행하여 항산화 효과를 측정한 결과, assai열매추출물의 농도가 높을수록 DPPH활성이 뛰어남을 알 수 있었고, ROS를 이용하여 항산화 효과를 확인하였다. 배양된 대식세포에 assai열매추출물을 농도별로 첨가한 결과, 농도가 높을수록 과산화수소에 의해 유도된 산화적 자극이 감소하였다. 또한 세포 생존에 미치는 영향을 알고자 assai열매추출물을 농도별로 첨가하여 24시간후 세포의 형태변화를 MTT assay로 실시한 결과, 산화적 자극에 의해 발생한 세포 손상이 assai 열매추출물의 농도가 높아질수록 감소하는 것이 확인되었다. 따라서 assai열매추출물은 천연 항산화제로서의 가능성을 보였다.