• 한국응용과학기술학회지
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• 제27권4호
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• pp.545-551
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• 2010

Hydrophobically monoendcapped poly(sodium acrylate)s formed hydrophobic microdomains in water. This was concluded on poly(sodium acrylate)s with a linear $C_{12}$-alkyl chain attached specifically at the end of the polymer. There was no well defined CMC (critical micelle concentration), but rather a gradual transition from a micelle free solution to a micelle solution. Steady state fluorescence spectroscopy indicates that the micro domains are rather hydrophobic. At pH 5 in the abscence of salt and at pH 9 in the prescence of 1 M sodium citrate the CAC (critical aggregation concentration) was in the range of 0.1 to 2.4 mM. However at pH 5 there was a linear increase in the transition concentration with a head-group size due to an increase in steric and electrostatic repulsions between polymer main chains. At pH 9 in the abscence of salt the transition concentration was in the range of 1 to 80 mM. For the larger polymers there was a effect which consisted of a concentration gradient of sodium counterion toward the hydrophobic domain. The effect was larger for the larger polymers because of the higher total sodium concentration and the less steep counterion concentration gradient.

• Journal of Ecology and Environment
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• 제44권3호
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• pp.162-177
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• 2020

Background: Ecologists have achieved much progress in the study of mechanisms that maintain species coexistence and diversity. In this paper, we reviewed a wide range of past research related to these topics, focusing on five theoretical bodies: (1) coexistence by niche differentiation, (2) coexistence without niche differentiation, (3) coexistence along environmental stress gradients, (4) coexistence under non-equilibrium versus equilibrium conditions, and (5) modern perspectives. Results: From the review, we identified that there are few models that can be generally and confidently applicable to different ecological systems. This problem arises mainly because most theories have not been substantiated by enough empirical research based on field data to test various coexistence hypotheses at different spatial scales. We also found that little is still known about the mechanisms of species coexistence under harsh environmental conditions. This is because most previous models treat disturbance as a key factor shaping community structure, but they do not explicitly deal with stressful systems with non-lethal conditions. We evaluated the mainstream ideas of niche differentiation and stochasticity for the coexistence of plant species across salt marsh creeks in southwestern Denmark. The results showed that diversity indices, such as Shannon-Wiener diversity, richness, and evenness, decreased with increasing surface elevation and increased with increasing niche overlap and niche breadth. The two niche parameters linearly decreased with increasing elevation. These findings imply a substantial influence of an equalizing mechanism that reduces differences in relative fitness among species in the highly stressful environments of the marsh. We propose that species evenness increases under very harsh conditions if the associated stress is not lethal. Finally, we present a conceptual model of patterns related to the level of environmental stress and niche characteristics along a microhabitat gradient (i.e., surface elevation). Conclusions: The ecology of stressful systems with non-lethal conditions will be increasingly important as ongoing global-scale climate change extends the period of chronic stresses that are not necessarily fatal to inhabiting plants. We recommend that more ecologists continue this line of research.

• 방사성폐기물학회지
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• 제8권4호
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• pp.303-309
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• 2010

사용후핵연료 건식처리공정(pyrochemical process)에서 LiCl-KCl 공융염의 회수는 방사성폐기물 부피감량과 원료물질 회수를 위해 반드시 필요하다. 본 논문은 진공증류공정을 이용하여 희토류 침전물(희토류 산염화물 또는 산화물)내 잔류하는 LiCl-KCl 공융염 회수에 관한 것이다. 진공증류시험장치에서 희토류 침전물내 공융염은 효과적으로 휘발 및 분리되었다. 분리된 공융염은 감압증류시험장내 세 지점에서 침적되거나 필터에 포집되으며, 침적되거나 포집된 공융염을 회수하는 것은 쉽지 않았다. 이 문제점을 해결하기 위해 감압조건에서 온도구배를 이용하여 공융염 거동을 제어할 수 있는 공융염 진공증류/응축회수 시스템을 개발하였으며, 이 장치를 이용하여 휘발된 공융염을 회수용기에서만 응축시켜 쉽게 회수할 수 있음을 확인하였다.

• 미생물학회지
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• 제46권3호
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• pp.286-290
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• 2010

C-1화합물은 고염분성 환경의 혐기적인 퇴적층에서 관찰되며, 이 퇴적층의 표면과 수면에는 호기성 메틸영양미생물의 잠재적인 서식지가 된다. 염전과 갯벌에서 채취한 토양 시료를 접종원으로 하여 메탄올을 탄소원과 에너지원으로 공급하고 염분농도에 따라 계대배양한 후 메탄올 산화 세균 성장 조건을 살펴 본 결과, 메탄올 산화 세균이 성장 할 수 있는 염분의 최대 농도는 20% 조건이었다. 변성 구배 젤 전기영동 (Denaturing gel gradient electrophoresis)을 이용하여 농화배양액 내 미생물 군집구조를 분석한 결과, 메탄올 산화 미생물인 Methylophaga 관련 세균이 우점하는 것으로 나타났다. 정량 PCR결과 고세균이 세균의 1-10%로 존재하는 것으로 나타났다. 세균용 항생제 실험결과, 메탄올 산화가 억제되어 고세균이 메탄올 산화에 관여하지 않는다는 것을 추정할 수 있었다. 이번 연구를 통해, 메틸영양세균이 고염분환경(염분 농도 20%까지)에서도 C-1 화합물을 산화할 수 있음을 확인 할 수 있었다.

• Geosciences Journal
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• 제22권6호
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• pp.1041-1052
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• 2018

A single-well push-drift-pull tracer test using two different tracers ($SF_6$ and salt) was performed at the Environmental Impact Test (EIT) site to determine suitable locations for monitoring wells and arrange them prior to artificial $CO_2$ injection and leak tests. Local-scale estimates of hydraulic properties (linear groundwater velocity and effective porosity) were obtained at the study site by the tracer test with two tracers. The mass recovery percentage of the volatile tracer ($SF_6$) was lower than that of the non-volatile tracer (salt) and increased drift time may make degassing of $SF_6$ intensified. The $CO_2$ leakage monitoring results for both unsaturated and saturated zones suggest that the $CO_2$ monitoring points should be located near points at which a high concentration gradient is expected. Based on the estimated hydraulic properties and tracer mass recovery rates, an optimal $CO_2$ monitoring network including boreholes for monitoring the unsaturated zone was constructed at the study site.

• 한국식품영양과학회지
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• 제42권7호
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• pp.1115-1124
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• 2013

한국산 꽃소금의 특성을 알아보기 위하여 국내에서 생산된 꽃소금 3종과 천일염 1종의 이화학적 및 미생물 분석을 실시하였다. 수분함량은 $10.54{\pm}0.10{\sim}13.82{\pm}0.12%$, 나머지 조단백, 조지방, 조섬유는 거의 존재하지 않았다. NaCl은 신의도산 꽃소금이 $78.81{\pm}0.28%$, 비금산 꽃소금이 $81.67{\pm}0.34%$, 도초산 꽃소금 $84.61{\pm}0.21%$, 도초산 천일염이 $80.82{\pm}0.17%$로 나타났다. 불용분, 사분은 각각 0.01~0.05%, 0.01~0.03%로 낮게 검출되었다. 미네랄 분석은 도초산 꽃소금에서 K과 Mg 함량이 2,975.23 mg/kg, 9,886.72 mg/kg으로 비교적 낮게 나타났다. Ca은 도초산 소금 2종이 945.53 mg/kg, 942.43 mg/kg으로 낮은 함량을 보였다. 중금속 As, Cd, Pb, Hg은 모두 규격 이하로 검출되었다. 소금결정을 관찰한 결과로 천일염과 꽃소금 모두 핵이 중복되어 겹으로 적층된 것을 확인하였으며 크기는 비금산 꽃소금이 $0.067{\times}0.067mm$로 가장 작고 도초산 천일염이 $0.112{\times}0.124mm$로 꽃소금에 비해 크게 나타났다. 소금의 색도는 꽃소금의 L값이 천일염에 비해 높아 밝게 확인되었다. 관능검사 결과로 짠맛은 NaCl 함량과 유사하며, 쓴맛은 K과 Mg 함량이 적은 도초산 꽃소금이 낮게 나타났다. 천일염에 비해 꽃소금의 단맛과 기호도가 더 높은 것으로 확인되었다. 호염균 동정 결과 19종 모두 Firmicutes로 꽃소금에서 Marinibacillus, Paenibacillus, Bacillus 속이 12종으로 확인되며, 천일염은 Planococcus, Staphylococcus, Bacillus 속 3종으로 검출되었다. DGGE 실험 결과로 도초산 꽃소금에서 16개의 band와 도초산 천일염에서 15개의 band를 확인하였다. 동정 결과 도초산 꽃소금에서 Cupriavidus sp. ATHA3(14.43%), Cupriavidus sp. TSA5(10.41%), Maritimibacter sp. YCSD61-2(8.13%), uncultured bacteria(68%)로 확인되었고, 도초산 천일염에서는 Dunaliella salina(4.76%), Cupriavidus sp. ATHA3(15.80%), uncultured Mycoplasmataceae bacteria(51.72%), uncultured bacteria(27%)로 확인되었다.

• 한방비만학회지
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• 제18권2호
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• pp.106-114
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• 2018

Objectives: We investigated about the microbial properties and changes in the efficacy of the Codonopsis lanceolata (CL) by natural fermentation. Methods: CL was fermented for four weeks in a well-ventilated place with 2.5% salt. pH, total sugar, total polyphenol, and total flavonoid were measured to determine fermentation characteristics according to fermentation period and salt treatment. Polymerase chain reaction denaturing gradient gel electrophoresis and random amplification of polymorphic DNA-polymerase chain reaction were carried out for microbial analysis during fermentation. In addition, HepG2 cell was cultured to check the lipid accumulation through oil red O staining and the glucose uptake was analyzed by measuring the 2-NBDG at C2C12 cell. Results: The pH level and the total sugar decreased with the CL fermentation. Total polyphenol and flavonoid increased after CL fermentation. It was confirmed that Leuconostoc mesenteroides were maintained continuously during fermentation. In the salt treatment CL, there was a sharp increase in Rahnella aquatilis. Lactobacillus plantarum matrix was observed in fermented CL. In addition, Lactococcus lactis, Weissella koreensis, R. aquatilis, L. plantarum, Leu. mesenteroides have been added to the salt treatment. Glucose uptake were significantly increased after fermentation with salt for four weeks. Lipid accumulation in the HepG2 cells was observed that there was difference (P<0.01) between free fatty acid group (100%) and decreased 4 weeks after fermentation (90.38%) at $800{\mu}g/mL$. Conclusions: Total polyphenol and flavonoid were increased after CL fermentation. Especially, percentage of the glucose uptake and lipid accumulation inhibition increased in CL fermentation with salt. It is expected that fermentation of salt treated CL will be more effective in diabetes and fatty liver.

• Journal of Microbiology and Biotechnology
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• 제26권6호
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• pp.1057-1062
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• 2016

Kimchi is a traditional Korean fermented vegetable food, the production of which involves brining of Korean cabbage, blending with various other ingredients (red pepper powder, garlic, ginger, salt-pickled seafood, etc.), and fermentation. Recently, kimchi has also become popular in the Western world because of its unique taste and beneficial properties such as antioxidant and antimutagenic activities, which are derived from the various raw materials and secondary metabolites of the fermentative microorganisms used during production. Despite these useful activities, analysis of the microbial community present in kimchi has received relatively little attention. The objective of this study was to evaluate the bacterial community structure from the raw materials, additives, and final kimchi product using the culture-independent method. Specifically, polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) was used to analyze the 16S rRNA partial sequences of the microflora. One primer set for bacteria, 341F^GC-518R, reliably produced amplicons from kimchi and its raw materials, and these bands were clearly separated on a 35-65% denaturing gradient gel. Overall, 117 16S rRNA fragments were identified by PCR-DGGE analysis. Pediococcus pentosaceus, Leuconostoc citreum, Leuconostoc gelidum, and Leuconostoc mesenteroides were the dominant bacteria in kimchi. The other strains identified were Tetragenococcus, Pseudomonas, Weissella, and uncultured bacterium. Comprehensive analysis of these microorganisms could provide a more detailed understanding of the biologically active components of kimchi and help improve its quality. PCR-DGGE analysis can be successfully applied to a fermented food to detect unculturable or other species.

• Journal of Ecology and Environment
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• 제32권2호
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• pp.115-121
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• 2009

In order to elucidate the mechanisms affecting plant distributions in the reclaimed dredging area in the Gwangyang steelworks, in the Gwangyang Bay, Korea, we examined soil characteristics and plant distributions in four study sites and a control site in the study area. Desalination occurring along a gradient with increasing elevation, resulting in decrease of soil pH, EC, P, K, Cl, Ca, Mg, and salt and an increase in soil T-N, silt, clay contents. From site 1 (the lowest-elevation site) to site 5 (the highest-elevation site), halophytes decreased in abundance and nonhalophytes increased. The dominant species in each site were: Phragmites communis, Limonium tetragonum, and 12 additional species at site 1, Carex pumila, Suaeda japonica, and 15 additional species at site 2, Spergularia marina, Scirpus planiculmis, and 22 additional species at site 3, Miscantus sinensis, Lespedeza bicolor, and 26 additional species at site 4 and Pinus thunberii, Rhododendron mucronulatum, and 39 additional species at site 5, which resembled a naturally-occurring P. thinbergii community. Cluster analysis of the vegetation data matrix grouped the 35 plots into 5 major groups, and cluster analysis using the soil environment data matrix revealed 4 major groups. CCA of the floristic and environmental data matrix showed a positive relationship of SAR, EC, Na, Cl, and Ca, which are related to salt, in the $1^{st}$ axis and $2^{nd}$ axis, but negative relationships for altitude, organic contents, silt, and clay contents. Notably, plant species in the reclaimed dredging area that were separated along the $1^{st}$ axis showed strong relationships with factors that related to salt. Long-term exposure to natural rainfall in the reclaimed dredging area changed the soil characteristics, such as salinity. This change in soil characteristics might alter the SAR, which affects plant survival strategies in a given habitat. These results strongly indicated that factors related to salt and elevation play important roles in determining the overall plant distribution in the reclaimed dredging area.

• The Korean Journal of Ecology
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• 제26권3호
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• pp.135-142
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• 2003

콩과식물의 염분 내성에 대한 질소원의 영향을 규명하기 위하여 4종 콩과식물을 선택하여 100 mM까지의 NaCl을 처리하였다. 염-민감성 종으로 알려진 대두와 팥은 염분 농도가 증가함에 따라 총 질소 함량이 점차 감소하는 반면, 아미노산 함량은 현저히 증가(100 mM NaCl 처리된 대두 무질소구의 경우 대조구의 4.7배)하여 높은 가용성/불용성 질소 비를 보였다. 대조적으로 염분 내성을 보이는 긴강남차와 자귀나무는 아미노산을 거의 함유하지 않았으며, 염 구배에 따라 총 질소 함량(특히 불용성 질소)이 점차 증가하는 양상을 보였다. 대두와 팥은 아미노산 중 asparagine (Asn)을 다량으로 함유하였으며, Asn은 이들 식물의 대표적인 질소의 수송 및 저장형태로서 염분 환경하에서 이들 식물의 세포질 내 삼투조절에 관여하는 것으로 생각된다. 염 환경에서 대두의 생장에 대한 질소원 및 농도의 영향은 5 mM NH₄NO₃-N 처리구에서 가장 높은 건물함량(10mM NaCl 처리구의 지상부건물함량의 경우 대조구의 약 1.5배)을 보였고, NH₄-N을 공급한 식물의 경우 질소를 공급하지 않은 대조구보다 생장이 저해되었으며, 처리 15일 이후 40과 80 mM NaCl 처리구에서 모두 고사하였다. 따라서 대두의 생장은 NH₄-N, 대조구, NO₃-N, NH₄NO₃-N의 순으로 질소공급량이 증가할수록 염에 대한 저항성이 증가하는 것으로 나타났다.