• Journal of Dairy Science and Biotechnology
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• 제33권2호
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• pp.119-127
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• 2015

낙농 미생물학에서 사용하는 주요 분석 방법들에 대한 지속적인 개정이 요구되어지고 있는 것이 사실이다. 현재 이용 가능한 자료들을 바탕으로 균주의 생리 및 대사 특성을 더 깊이 이해할 수 있으며, LAB와 probiotic 생리적 상태를 측정할 수 있는 기술을 개발할 수 있다. 예를 들어, 고유 균주의 생화학 반응으로부터 얻은 생물학적 생리학적 지식을 바탕으로 발색형광배지(chromogenic media)의 개발이 가능하다. 이 기술은 오랫동안 사용되어온 한천 배지보다 사용법이 간단하며, 미생물을 제어할 수 있다. 유망한 유동세포계수법(flow cytometry, FC) 기술은 우유, 요구르트, 그 외 발효 유제품의 혼합 배양의 분석에 뛰어나다. 이 기술은 공정 과정 중에 또는 생산품의 유통 기한 관리에 사용될 수 있지만, 이 기술을 사용하기 위해서는 우유 단백질에 의해서 생성되는 인공 산물을 방지하기 위해 최적화 되어야 한다. 또한 유동세포계수법(flow cytometry, FC)은 정량 한계가 높기 때문에, 현재 사용하고 있는 탐침(probe)은 종 또는 속이 아닌 표적 세포 구성을 분석한다. 따라서 유동세포계수법(flow cytometry, FC)은 특정 물질의 계수보다는 생리적 상태를 측정에 더 적합한 기술이라고 볼 수 있다. Omics 자료를 통해 생리적 상태를 더 신속하게 측정할 수 있는 핵심적인 생체지표 확인이 가능해졌다. PCR은 이미 식품매개 병원균 및 부패균의 검출에 일상적으로 사용되고 있다. 이 기술은 더욱 나아가 발효균 및 probiotic 박테리아 검출에도 사용되어 핵산 추출, PCR 과정, 자료 해석을 표준화 시킬 수 있으며, 또한 다른 기술에 비해 PCR은 표적 발효 균주를 더 신속하게 선택하며, 공정 과정을 최적상태로 유지시킬 수 있을 것이다. LAB와 probiotic의 적응성 및 생리적 상태의 연구에 필요한 기준, 특허품, 상업화된 신속분석장치(kit)는 아직까지 개발되지 않았다. 본 총설 논문에서는 여러 가지 기술을 검토함으로써 이 모든 기술에는 2가지 주요한 요인이 있다. 첫 번째는 낙농업 산업의 특정 요구에 따른 방법의 평가이며, 두 번째는 공식적인 기준에 따른 검증이다. 사실상 식품매개 병원균의 특성 분석에 사용될 수 있는 표준법이 개발되고 검증되었지만, LAB, probiotic 등의 박테리아 분석에 있어서 표준화된 방법과 진단산업과의 연관성이 부족한 것이 사실이다. 낙농 업계에 의해서 수행되어진 품질관리의 양을 고려해 볼 때 이것은 매우 중요하게 인식되어야 할 부분이다.

• Fibers and Polymers
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• 제7권4호
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• pp.333-338
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• 2006

Silk fibroin (SF) fiber from the Antheraea pernyi silkworm was treated with a 1.23 N iodine-potassium iodide ($I_2-KI$) aqueous solution, and the structure and physical properties were investigated to clarify the effects of the iodine treatment. The noticeably high weight gain value of SF fiber, about 25 wt% was attributed to the absorption of polyiodide ions in the form of $I_3{^-}\;and\;I_5{^-}$. Fourier transform infrared spectroscopy and X-ray diffraction measurements suggested that polyiodide ions mainly entered the amorphous region. In addition, a new sharp reflection on the meridional direction, corresponding to a period of $7.0{\AA}$, was observed and indicated the possibility of the formation of mesophase structure of ${\beta}$-conformation chains. Dynamic viscoelastic measurements showed that the damping tan ${\delta}$ peak at $270^{\circ}C$ gradually shifted to lower temperature in the iodinated SF fibers, suggesting an enhancement of the molecular motion of the fibroin chains induced by the presence of polyiodide ions. With heating above $254^{\circ}C$, the iodine component introduced intermolecular cross-linking of SF, and the melt flow of the sample was inhibited. The thermal decomposition stability of fibroin molecules was greatly enhanced by iodine treatment.

• 한국막학회:학술대회논문집
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• 한국막학회 1996년도 춘계 총회 및 학술발표회
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• pp.16-19
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• 1996

Separation with synthetic membrane have become increasingly important processes in many fields. In the most application of membrane process, polymer membrane is used. the main advantage of polymers as a material for membrane preparation is the relative simplicity of this film formation which enables one to obtain rather high permeability rates. However, polymeric membranes have several limitations, such as high temperature instability, swelling and decomposition in organic solvent, et. al.. These limitations can be overcome by inorganic membrane. At the present time, commercially available inorganic membranes have pore diameters ranging 5nm to 50mm, and the predominant flow regime in such membrane is Knudsen diffusion. Since the Knudsen permeability is directly proportional to the molecular velocity, gases can be separated due to their molecular masses. However, this separation mechanism is only of important for light gases such as H2 and He. Other separation mechanisms like surface diffusion, active diffusion can play an important role only with very small pore diameters(2nm) and give rise to large permselectivities. Therefore, preparation of inorganic membrane with nano-sized pore have been attracting more and more attention.

• Molecules and Cells
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• 제38권6호
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• pp.518-527
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• 2015

Controlled release of medications remains the most convenient way to deliver drugs. In this study, we precipitated gold nanoparticles with quercetin. We loaded gold-quercetin into poly(DL-lactide-co-glycolide) nanoparticles (NQ) and tested the biological activity of NQ on HepG2 hepatocarcinoma cells to acquire the sustained release property. We determined by circular dichroism spectroscopy that NQ effectively caused conformational changes in DNA and modulated different proteins related to epigenetic modifications and c ell cycle control. The mitochondrial membrane potential (MMP), reactive oxygen species (ROS), cell cycle, apoptosis, DNA damage, and caspase 3 activity were analyzed by flow cytometry, and the expression profiles of different anti- and pro-apoptotic as well as epigenetic signals were studied by immunoblotting. A cytotoxicity assay indicated that NQ preferentially killed cancer cells, compared to normal cells. NQ interacted with HepG2 cell DNA and reduced histone deacetylases to control cell proliferation and arrest the cell cycle at the sub-G stage. Activities of cell cycle-related proteins, such as $p21^{WAF}$, cdk1, and pAkt, were modulated. NQ induced apoptosis in HepG2 cells by activating p53-ROS crosstalk and induces epigenetic modifications leading to inhibited proliferation and cell cycle arrest.

• 대한기계학회논문집B
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• 제22권5호
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• pp.640-650
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• 1998

Pumping performances of a helical molecular drag dump(MDP) and of a radial MDPs are numerically analyzed by using the direct simulation Monte Carlo (DSMC) method. A helical- and radial-MDP have rotating pumping channels cut on a cylinder and on a disk, respectively. For a helical MDP, the present results agree quantitatively with the previously known numerical results. For radial MDPs, both of the Type 1 (having pumping channels cut on the stationary disk) and of the Type 2 (having pumping channels cut on the rotating disk) are analyzed to predict their performances for various parameters, i.e., the radius of curvature center of the channel wall, the depth of the channel, the clearance between housing and disk, and the rotating speed. The results show that the performance of the Type 2 is superior to that of the Type 1, and that for all types the pumping efficiency decreases as the clearance increases. Also, the radial type MDP has larger leakage losses in the direction of pumping channel than does the helical one.

• 동의생리병리학회지
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• 제17권6호
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• pp.1519-1523
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• 2003

Glehnia littoralis Fr. Schmidt (Umbelliferae) is a short-lived herbaceous species that are mostly distributed throughout East Asia. Although G. littoralis has been regarded as ecologically important one, there is no report on population structure in Korea. Starch gel electrophoresis was used to investigate the allozyme variation and genetic structure of Korean populations of this species. A high level of genetic variation was found in G. littoral is populations. Nine enzymes revealed 18 loci, of which 12 were polymorphic (66.7%). Genetic diversity at the species and population levels were 0.159 and 0.129, respectively. The sexual and asexual reproduction, high fecundity, and colonization process are proposed as possible factors contributing to genetic diversity. An indirect estimate of the number of migrants per generation (Nm = 1.45) indicated that gene flow was not extensive among Korean populations of this species. It is suggested that the ability of vegetation and artificial selection may have played roles in shaping the population structure of this species. we recommend that a desirable conservation population should be included at least 30 plants per population and especially those with high variation.

• 한국임상수의학회지
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• 제16권1호
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• pp.31-36
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• 1999

The aim of this study is to determine the phagocytosis-promoting factor(s) for feline peripheral blood polymorphonuclear cells (PMN) by culture supernatant from mono-nuclear cells (MNC) treated with egg white derivatives (EWD). The phagocytic activity of PMN was analyzed by a flow cytometry system. The EWD did not show direct effect on the phagocytic response of PMN. The phagocytic activity of PMN was enhanced by culture supernatant from MNC but not PMN treated with EWD. Therefore, it was suggested that the enhanced phagocytic activity of feline PMN could be mediated by humoral factor(s) released from MNC treated with EWD. Thus, the phagocytosis-promoting factor(s) in supernatant fraction from MNC culture treated with EWD were isolated by reverse phase high pressure liquid chromatography. The resulting supernatant fraction on 29.02 minutes of retention time showed high phagocytic activity of PMN. The molecular weight of this supernatant fraction was 16 to 18 kDa when analyzed by capillary electrophoresis. The isoelectric point was pH 5.76 when assessed by ion-exchange chromatography. These results suggest that EWD stimulates feline MNC to elaborate a phagocytosis-promoting factor, 16 to 18 kDa of molecular weight, which could be an important mediator for the enhancement of phagocytic activity of feline peripheral blood phagocytes. Further study will be needed to elucidate this phagocytic factor.

• Bulletin of the Korean Chemical Society
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• 제32권4호
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• pp.1221-1227
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• 2011

Ethyl pyruvate (EP) is known as a scavenger of reactive oxygen species (ROS) in the body through its role in the donation of diketone groups to metals to form an EP-metal complex. In order to develop a method for the quantification of EP in biological media, a sensitive and specific, high-performance liquid chromatographyelectrospray ionization-mass spectrometry (HPLC-ESI/MS) method is used to determine the EP-alkali metal ion binding species. The analyte was separated on a ZORBOX SB-C8 ($3.5{\mu}m$, $30mm{\times}2.1mm$ I.D.) column and analyzed in selected ion monitoring (SIM) mode with a positive ESI interface using the m/z 255 $[2M + Na]^+$ ion. The method was validated over the concentration range of $0.5-60.0\;{\mu}g$/mL under 1/9 (v/v) of acetonitrile/methanol solvent system with flow rate 0.05 mL/min. The limit of quantification (LOQ) was $0.5{\mu}g$/mL.

• 대한방사성의약품학회지
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• 제2권2호
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• pp.73-83
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• 2016

Imaging hypoxia using positron emission tomography (PET) is of great importance for cancer therapy. [$^{18}F$] Fluoromisonidazole (FMISO) was the first PET agent used for imaging tumor hypoxia. Various radiolabeled nitroimidazole derivatives such as [$^{18}F$]fluoroerythronitroimidazole (FETNIM), [$^{18}F$]1-${\alpha}$-D-(2-deoxy-2-fluoroarabinofuranosyl)-2-nitroimidazole(FAZA), 2-(2-nitroimidazol-1-yl)-N-(3,3,3-[18F]-trifluoropropyl)acetamide ([$^{18}F$]EF-3), [$^{18}F$]2-(2-nitro-1H-imidazol-1-yl)-N-(2,2,3,3,3-pentafluoropropyl) acetamide (EF-5), 3-[$^{18}F$]fluoro-2-(4-((2-nitro-1H-imidazol-1-yl)methyl)-1H-1,2,3,-triazol-1-yl)-propan-1-ol ([$^{18}F$]HX-4), and [$^{18}F$]fluoroetanidazole (FETA) were developed successively. However, these imaging agents still produce PET images with limited resolution; the lower blood flow in hypoxic tumors compared to normoxic tumors results in low uptake of the agents in hypoxic tumors. Thus, the development of better imaging agents is necessary.

• Journal of Ecology and Environment
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• 제29권2호
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• pp.175-183
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• 2006

The discovery of deep-sea hydrothermal vents and their ecosystems is a monumental landmark in the history of Ocean Sciences. Deep-sea hydrothermal vents are scattered along the global mid-ocean ridges and back-arc basins. Under sea volcanic phenomena related to underlying magma activities along mid-ocean ridges generate extreme habitats for highly specialized communities of animals. Multidisciplinary research efforts during past three decades since the first discovery of hydrothermal vents along the Galapagos Rift in 1977 revealed fundamental components of physiology, ecology, and evolution of specialized vent communities of micro and macro fauna. Heterogeneous regional geological settings and tectonic plate history have been considered as important geophysical and evolutionary factors for current patterns of taxonomic composition and distribution of vent faunas among venting sites in the World Ocean basins. It was found that these communities are based on primary production of chemosynthetic bacteria which directly utilize reduced compounds, mostly $H_2S$ and $CH_4$, mixed in vent fluids. Symbioses between these bacteria and their hosts, vent invertebrates, are foundation of the vent ecosystem. Gene flow and population genetic studies in parallel with larval biology began to unveil hidden dispersal barrier under deep sea as well as various dispersal characteristics cross taxa. Comparative molecular phylogenetics of vent animals revealed that vent faunas are closely related to those of cold-water seeps in general. In perspective additional interesting discoveries are anticipated particularly with further refined and expanded studies aided by new instrumental technologies.