• KSBB Journal
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• 제10권1호
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• pp.105-112
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• 1995

본 연구에서는 LB기법에 의하여 분자수준으로 고 정화된 효소를 이용하여 에탄올의 양을 측정하는 광섬유 바이오센서가 개발되 었다. ADH는 arachidic acid의 단분자막에 LB기법으로 고정화된다. 센서의 출력신호를 분석하기 위하여 고정화된 ADH의 효소 반응은 ordered multisubstrate mechanism을 이용 하여 검토되었다. 광학 측정 시스템이 제시되었으며, 센서의 출력신호는 에단올의 농도에 비례하여 증가 하며 LB막에 누적된 누적충수와 관련이 있음을 알 수 있었다. LB막의 누적된 누적충수를 20충으로 증가하면 센서의 신호출력 범위가 확장되어 45mM의 고농도 에탄올도 측정할 수 있었다. 순수지질의 단 분자막과 효소가 흡착된 지질의 단분자막의 $\pi$-Aisotherm은 중성의 subphase에서 각기 다른 전하를 띠는 세 가지 종류의 지질에 대하여 조사되었다. ADH의 흡착도가 가장 우수한 지질은 arachidic a acid이며 이는 중성의 sub phase에서 양의 전하를 띠는 ADH 분자와 읍극의 전하를 띠는 arachidic a acid 분자 사이에 작용하는 정전기력에 기인한 것이다.

• BMB Reports
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• 제45권9호
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• pp.538-543
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• 2012

We evaluated the expression of the costimulatory molecules CD80 and CD83 and major histocompatibility (MHC) class II induced by 2,4-dinitrofluorobenzene (DNFB) in the RAW 264.7 macrophage cell line. In contrast to the previously reported effect of DNFB on dendritic cells, CD86 expression did not change. Furthermore, we observed that the CD83 expression level transiently increased and then decreased. Induction of CD80 and MHC class II molecule expression and a decrease in CD83 expression by DNFB in vitro were also confirmed in splenocytes of BALB/c and NC/Nga mice. However, DNFB did not influence CD83 expression in peritoneal $CD11b^+$ cells from BALB/c or NC/Nga mice. Detailed in vivo experiments and further studies on the possible contribution of $CD11b^+$ cells to induce atopic dermatitis (AD) would be helpful to attain a better understanding of AD pathogenesis.

• BMB Reports
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• 제40권4호
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• pp.453-458
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• 2007

Bacterial luciferase is a heterodimeric enzyme, which catalyzes the light emission reaction, utilizing reduced FMN (FMNH2), a long chain aliphatic aldehyde and $O_2$, to produce green-blue light. This enzyme can be readily classed as slow or fast decay based on their rate of luminescence decay in a single turnover. Mutation of Glu175 in $\alpha$ subunit to Gly converted slow decay Xenorhabdus Luminescence luciferase to fast decay one. The following studies revealed that changing the luciferase flexibility and lake of Glu-flavin interactions are responsible for the unusual kinetic properties of mutant enzyme. Optical and thermodynamics studies have caused a decrease in free energy and anisotropy of mutant enzyme. Moreover, the role of Glu175 in transition state of folding pathway by use of stopped-flow fluorescence technique has been studied which suggesting that Glu175 is not involved in transition state of folding and appears as surface residue of the nucleus or as a member of one of a few alternative folding nuclei. These results suggest that mutation of Glu175 to Gly extended the structure of Xenorhabdus Luminescence luciferase, locally.

• 한국항공우주학회지
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• 제46권6호
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• pp.519-526
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• 2018

우주 자원을 분석하기 위해서는 지구로 가져와야 한다는 단점이 있었다. 하지만, 레이저 유도 분해 분광법(Laser-induced breakdown spectroscopy, LIBS)고 라만 분광법(Raman spectroscopy)을 활용한다면 우주 광물의 실시간 정성 정량적으로 분석이 가능하다. 레이저 유도 분해 분광법은 높은 에너지의 레이저를 물질 표면에 집중시켜 플라즈마를 생성한후, 방출되는 빛을 분광기를 통해 획득하여 원자 구성을 분석하는 분광법이다. 라만 분광법은 레이저를 물질 표면에 조사시켜 산란되는 빛을 측정하여 분자구조를 분석하는 분광법이다. 이 두 가지 분광법은 각각 미지의 광물의 원자 분자를 분석하는 상호보완적인 분광법으로 우주탑재체로서 효율적인 장점을 가지고 있다. 본 연구에서는 주성분 분석법(Principal Component Analysis, PCA)을 활용하여 광물을 정성적으로 분석했다. 또한, 두 가지 광물을 혼합한 시료를 제작하여 구성 성분 비율에 따른 신호 세기로부터 물질의 구성 비율을 예측하는 정량분석을 시행하였다.

• BMB Reports
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• 제37권3호
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• pp.330-338
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• 2004

Different types of cardiotoxin (I-V and n) were isolated and purified from the venom of the Taiwan cobra (Naja naja atra). The effects of these cardiotoxins were studied on membrane-bound acetylcholinesterase, which was isolated from a sheep's brain cortex. The results showed that cardiotoxins I-III, V, and n activated the enzyme by modification of substrate inhibition, but cardiotoxin IV's reaction was different. The inhibition and activation of acetylcholinesterase were linked to the functions of the hydrophobicity index, presence of a cationic cluster, and the accessible arginine residue. Our results indicate that Cardiotoxins have neither a cationic cluster nor an arginine residue in their surface area of loop I; therefore, in contrast to fasciculin, cardiotoxins are attached by loop II to the peripheral site of the enzyme. As a result, fasciculin seems to stabilize nonfunctional conformation, but cardiotoxins seem to stabilize the functional conformation of the enzyme. Based on our experimental and theoretical findings, similar secondary and tertiary structures of cardiotoxins and fasciculin seem to have an opposite function once they interact with acetylcholinesterase.

• Parasites, Hosts and Diseases
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• 제48권1호
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• pp.43-48
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• 2010

Cryptosporidium and Giardia are 2 protozoan parasites responsible for waterborne diseases outbreaks worldwide. In order to assess the prevalence of these protozoans in drinking water samples in the northern part of Portugal and the risk of human infection, we have established a long term program aiming at pinpointing the sources of surface water, drinking water, and environmental contamination, working with the water-supply industry. Total 43 sources of drinking water samples were selected, and a total of 167 samples were analyzed using the Method 1623. Sensitivity assays regarding the genetic characterization by PCR and sequencing of the genes, 18S SSU rRNA, for Cryptosporidium spp. and $\beta$, -giardin for G. duodenalis were set in the laboratory. According to the defined criteria, molecular analysis was performed over 4 samples. Environmental stages of the protozoa were detected in 25.7% (43 out of 167) of the water samples, 8.4% (14 out of 167) with cysts of Giardia, 10.2% (17 out of 167) with oocysts of Cryptosporidium and 7.2% (12 out of 167) for both species. The mean concentrations were 0.1-12.7 oocysts of Cryptosporidium spp. per 10 L and 0.1-108.3 cysts of Giardia duodenalis per 10 L. Our results suggest that the efficiency in drinking water plants must be ameliorated in their efficiency in reducing the levels of contamination. We suggest the implementation of systematic monitoring programs for both protozoa. To authors' knowledge, this is the first report evaluating the concentration of environmental stages of Cryptosporidium and Giardia in drinking water samples in the northern part of Portugal.

• 상하수도학회지
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• 제32권3호
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• pp.279-289
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• 2018

N-nitrosodimethylamine (NDMA) is a class of disinfection byproducts and a frequently detected nitrosamine with carcinogenic potentials. This review summarizes NDMA precursors, their formation mechanisms in chloraminated water, and mitigation strategies. Understanding the formation mechanism and characteristics of precursors is essential for developing a mitigation strategy. Dimethylamine (DMA), the most widely studied NDMA precursor, has an NDMA molar yield up to 3%. In comparison, a subset of tertiary amines, e.g., pharmaceuticals, generate up to 90% upon chloramination. Potent NDMA precursors, are characterized by their negative partial charge, low planarity values and molecular weight, and high bond length and $pK_a$ values. A nucleophilic substitution of tertiary amine on chloramine is a key reason for the high NDMA yield from the most potent NDMA precursors. The distribution and fate of NDMA in surface water, aquifers, and its formation in the distribution system can be mitigated through two strategies: (1) degrading or/removing NDMA after its formation and (2) pre-treatment of its precursor's prior chloramination.

• 한국수정란이식학회지
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• 제13권2호
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• pp.179-190
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• 1998

Prolactin (PRL) surge in cycling rats at proestrous afternoon has previously been reported as an inducer of apoptotic cell death of luteal cells. This death-inducing action of PRL seeins unusual, because PRL can he categorized as a cell-survival factor, if other known physiological functions of PRL are taken into account. In this study, the apoptotic action of PRL was assessed in cultured cells prepared from rat luteal tissue and underlying molecular /cellular mechanism of PRL-induced luteolysis was analyzed. The latest crop of corpora lutea (CLs) were enucleated from rat ovaries at 18:00 h on the proestrous day before the next ovulation. Donor rats were pretreated with CB154, a dopamine agonist, in order to he exempted from the endogenous PRL surge. The harvested GLs were dispersed and cultured with or without PRL (2$\mu$g /ml) for 24 or 48 h. An addition of PRL to the culture medium changed the parameters indicative of cell death via apoptosis: a decrease in cell viability (MTT) and an increase in chromatin condensation. Most of the DNA breakdown in nuclei induced by PRL occurred in steroidogenic cells which were identified by 3$\beta$-HSD activity staining, and the number of 3$\beta$-HSD-positivecells were significantly decreased. Interestingly, most of the cells with an apoptotic nucleus adhered to one or more intact and seemingly non-steroidogenic cells. Because the expression of Fas has heen shown to be abundant in murine ovary, and Fas is known to have an exact physiological role in occurrence of apoptotic cell death, the membrane form-Fas ligand (rnFasL) was quantified in the cell lysate. An addition of PRL increased expression of mFasL. Moreover, an addition of concanavalin A (ConA), a T-cell specific activator, in place of PRL, enhanced the apoptotic parameters. Cumulatively, the apoptotic PRL action was addressed to cells unknown than steroidogenic lute~ cells. The most prohable candidate for the direct target cells is Tcells in the luteal tissue that can express mFasL in response to PRL.

• 한국연소학회지
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• 제7권4호
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• pp.36-44
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• 2002

Carbon molecules with closed-cage structures are called fullerenes $(C_{60},\;C_{70})$, whose applications include super-conductors, sensors, catalysts, optical and electronic device, polymer composites, and biological and medical materials. The synthesis of fullerenes has been recently studied with low-pressure benzene/argon/oxygen flames. The formation of fullerene is known as molecular weight growth processes of PAHs (polycyclic aromatic hydrocarbon). This study presents results of PAHs and fullerene measurements performed in a low-pressure benzene/argon/oxygen normal co-flow laminar diffusion flame. Through the central tube of the burner, benzene vapors carried by argon are injected. The benzene vapors are made in a temperature-controlled bubbler. The burner is located in a chamber, equipped with a sampling system for direct collection of condensable species from the flame, and exhausted to a vacuum pump. Samples of the condensable are analyzed by HPLC (High Performance Liquid Chromatography) to determine the yields of PAHs and fullerene. Also, we computed mole fraction of fullerene and PAHs in a nearly sooting low pressure premixed, one-dimensional benzene/argon/oxygen flame (equivalence ratio ${\Phi}=2.4$, pressure=5.33kPa). The object of computation was to investigate the formation mechanism of fullerenes and PAHs. The computations were performed with CHEMKIN/PREMIX. As a result of this study, fullerenes were synthesized in a low pressure (20torr) $C_6H_6/Ar/O_2$ flames and the highest concentration of fullerene was detected just above the visible surface of a flame.

• BMB Reports
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• 제32권6호
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• pp.561-566
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• 1999

CA(1-8)-ME(1-12) [CA-ME], composed of cecropin A(1-8) and melittin(1-12), is a synthetic antimicrobial peptide having potent antibacterial and antitumor activities with minimal hemolytic activity. In order to investigate the effects of the flexible hinge sequence, Gly-Ile-Gly, of CA-ME on antibiotic activity, CA-ME and three analogues, CA-ME1, CA-ME2, and CA-ME3, were synthesized. The Gly-Ile-Gly sequence of Ca-ME was deleted in CA-ME1 and replaced with Pro and Gly-Pro-Gly in CA-ME2 and CA-ME3, respectively. CA-ME1 and CA-ME3 showed a significant decrease in antitumor activity and phospholipid vesicle-disrupting ability. However, CA-ME2 showed similar antitumor and vesicle-disrupting activities, as compared with CA-ME. These results suggest that the flexibility or ${\beta}$-turn induced by Gly-Ile-Gly or Pro in the central part of CA-ME may be important in the electrostatic interaction of the N-terminus cationic ${\alpha}$-helical region with the cell membrane surface and the hydrophobic interaction of the C-terminus amphipathic ${\alpha}$-helical region with the hydrophobic acyl chains in the cell membrane. CA-ME3 exhibited lower antitumor and vesicle-disrupting activities than CA-ME and CA-ME2. This result suggests that the excessive ${\beta}$-turn structure caused by the Gly-Pro-Gly sequence in CA-ME3 seems to interrupt ion channel/pore formation in the lipid bilayer. We concluded that the appropriate flexibility or bilayer. We concluded that the appropriate flexibility or ${\beta}$-turn structure provided by the central hinge is responsible for the effective antibiotic activity of the antimicrobial peptides with the helix-hinge-helix structure.