• Journal of Microbiology and Biotechnology
• /
• 제21권6호
• /
• pp.659-664
• /
• 2011

Staphylococcus aureus (SA) bacteremia is associated with high mortality, and often results in metastatic infections. The methicillin-resistant SA (MRSA) is an urgent health care issue, as nosocomial infections with these bacteria represent limited treatment alternatives. Samples of whole blood containing challenge inoculums of SA and MRSA strains were passed through columns packed with surfaceheparinized polyethylene beads. The bound bacteria were eluted and quantitatively determined by culturing and by real-time PCR. Significant amounts of both SA and MRSA adhered to the heparinized beads (more than 65% of inoculated bacteria). After rinsing with buffer at high ionic strength, viable bacteria or bacterial DNA were eluted from the columns, indicating that the binding was specific. The conclusions that can be made from these experiments are that, as earlier reported in the literature, the high affinity of SA to heparin is retained in whole blood, and MRSA in whole blood binds to heparin with similar or higher affinity than SA. It should be possible to lower the amount of SA and/or MRSA from the blood of infected patients to levels that could be taken care of by the immune system. In previous studies, we have shown that passing blood from septic patients over beads coated with end-point-attached, biologically active heparin is a useful technique for regulating the levels of heparinbinding cytokine. These findings in combination with the present findings indicate the possibility of creating an apheresis technology for treatment of sepsis caused by SA and/or MRSA.

• BMB Reports
• /
• 제28권1호
• /
• pp.72-78
• /
• 1995

Time-dependent inactivation of E. coli GTP cyclohydrolase I with a 2',3'-dialdehyde derivative of GTP (oGTP) was directed to the active site of the enzyme, and was dependent on the concentration of oGTP. The kinetics of inactivation were biphasic with a rapid reaction occurring immediately upon exposure of the enzyme to oGTP followed by a slow rate of inactivation. The $K_i$ value of oGTP for the enzyme was 0.25 mM. Inactivation was prevented by preincubation of the enzyme with GTP, the substrate of the enzyme. At 100% inactivation, 2.3 mol of [8.5'-$^3H$]oGTP were bound per each enzyme subunit, which consists of two identical polypeptides. The active site residue which reacted with the affinity label was lysine. oGTP interacted selectively with the ${\varepsilon}$-amino group of lysine in the GTP-binding site to form a morpholine-like structure which was stable without sodium borohydride treatment. However, triphosphate group was eliminated during the hydrolysis step. To identify the active site of the enzyme, [8.5'-$^3H$]oGTP-labeled enzyme was cleaved by endoproteinase Lys-C, and the $^3H$-labeled peptide was purified by HPLC. The amino acid sequence of the active site peptide was Pro-Ser-Leu-Ser-Lys, which corresponds to the aminoterminal sequence of the enzyme.

• 대한화학회지
• /
• 제51권1호
• /
• pp.7-13
• /
• 2007

옥사졸 고리를 포함하는 lexitropsin에서, DNA minor groove의 구아닌-시토신 염기쌍의 구아닌과 수소결합을 형성하는데 중요 역할을 하는 옥사졸에 대해, 양성자화 될 때 가능한 두 가지 형태에 대해 DFT 계산을 통해 구조를 최적화시켰다. 최적화된 구조에 대해 B3LYP/6-31G* 수준에서 양성자 친화도를 계산하였다. 그 결과 옥사졸의 가능한 두 가지 형태 가운데 옥사졸의 질소 원자가 DNA minor groove 쪽으로 배향된 구조가 산소 원자가 minor groove 쪽으로 배향된 구조보다 양성자 친화도가 더 큼을 알 수 있었으며, 분자정전기 전위로 확인할 수 있었다. 아울러 양성자 친화도에 미치는 치환기 효과를 알아보기 위하여 여러 전자 주는 기와 전자 받는 기를 치환시켜 치환기 성질에 따른 양성자 친화도를 조사하였으며, 전자를 받는 기 보다 전자를 주는 기가 치환 되었을 때 양성자 친화도가 증가함을 알았다.

• Journal of Microbiology and Biotechnology
• /
• 제28권10호
• /
• pp.1589-1603
• /
• 2018

Twenty analogs of $[Orn^6,D-Ala^9]{\alpha}-factor$ were synthesized and assayed for their biological activities: seven analogs of $[Orn^6,X^9]{\alpha}-factor$, seven analogs of $[X^6,D-Ala^9]{\alpha}-factor$, five analogs of $[X^5,X^6,D-Ala^9]{\alpha}-factor$, and native ${\alpha}-factor$ (X = amino acids). Their biological activities (halo, gene induction, and affinity) were measured using S. cerevisiae Y7925 and LM102 and compared with those of native ${\alpha}-factor$ (100%). G protein-coupled receptor was expressed in strain LM102 containing pESC-LEU-STE2 vector. $[Dap^6,D-Ala^9]{\alpha}-factor$ with weak halo activity (10%) showed the highest receptor affinity (> 230%) and the highest gene induction activity (167%). $[Arg^6,D-Ala^9]{\alpha}-factor$ showed the highest halo activity (2,000%). The number of active binding sites per cell (about 20,000 for strain LM102) was determined using a newly-designed fluorescence-based detector, $[Arg^6,D-Ala^9]{\alpha}-factor-Edan$, with high sensitivity (12,500-fold higher than the absorption-based detector $[Orn^6]{\alpha}-factor-[Cys]_3$).

• 대한화학회지
• /
• 제53권3호
• /
• pp.257-265
• /
• 2009

$Cu^{+}$ 및 $Cu^{2+}$와 proline의 결합형태에 따른 구조 및 금속 친화도를 DFT(Density Functional Theory) 방법으로 조사하였다. 금속-proline의 결합과 여러 결합형태에 따른 에너지 순서는 $Cu^{+}$-Proline및 $Cu^{2+}$-proline 착화합물에서 서로 매우 상이함을 알았다. $Cu^{+}$-Proline의 경우, 바닥상태의 구조는 $Cu^{+}$가 중성 proline의 카르보닐 산소 및 이미노기 질소에 배위된 두 자리 배위를 하며, 이에 비해 $Cu^{2+}$-Proline 의 바닥상태의 구조는 zwitter이온 형태 proline의 카르복시기의 두 산소 사이에 chelation을 형성하는 구조임을 확인하였다. 가장 안정한 $Cu^{+}$-Proline 착화합물에서 proline의 금속 이온 친화도는 6-311++G(d,p) 수준에서 76.0 kcal/mol로 계산되었으며, proline의 $Cu^{2+}$ 이온 친화도는 258.5 kcal/mol로 나타났다.

• 한국콘텐츠학회논문지
• /
• 제15권9호
• /
• pp.418-424
• /
• 2015

본 연구에서는 비방사능 값에 따른 소동물 in vivo실험에서 어느 정도의 비방사능에서부터 수용체-리간드의 결합능력의 변화와 선조체에서의 방사능 집적에 변화가 있는지를 규명하고자 실험을 진행하다. 18F-Fallypride을 3가지 값 ; 높은 비방사능 : 43.29~74 GBq/umol, 중간 비방사능 : 20.72~29.23 GBq/umol, 낮은 비방사능 : 6.29~8.51 GBq/umol)으로 나누어 순차적으로 혈관주사 후 Micro PET을 이용하여 90분 동적 스캔 하였다. 스캔 후 양쪽 선조체에서 Binding Potential(BP)을 구한 후 비교 분석하였다. 높은 비방사능과 낮은 비방사능, 중간 비방사능과 낮은 비방사능에서 유의한 차이가 나타났다. 또한 18F-Fallypride을 이용한 PET 영상비교에서는 높은 비방사능과 중간 비방사능에서는 선조체 에서 높은 방사능집적을 보여주었지만, 낮은 비방사능에서는 다른 두 비방사능에 비해 낮은 방사능 집적을 볼 수 있었다. 이는 18F-Fallypride의 약동학적 특성상 D2/D3에 대한 친화성이 좋기 때문에 비방사능 값이 어느 정도 떨어진 상태에서도 BP의 차이가 크지 않았다. 하지만 높은 비방사능에 비해 6.5배 낮은 비방사능 값 부터는 이미지 및 BP의 차이가 유의하게 나왔으므로 앞으로 18F-Fallyprdie을 이용한 선조체 PET연구에서는 이를 고려하여 실험 할 필요가 있을 것이다.

• Reproductive and Developmental Biology
• /
• 제30권3호
• /
• pp.169-174
• /
• 2006

돼지 페르몬성 분자를 탐색하기 위하여 일련의 green odorant로서 기질 분자인 2-(Cyclohexyloxy)tetrahydrofurane 유도체들의 정량적인 구조와 수용체인 porcine odorant binding protein(pOBP) 사이의 결합 친화력 상수($p(Od)_{50}$)에 대한 비교 분자 유사성 지수 분석(CoMSIA)을 실행하였다. 가장 양호한 CoMSIA 모델(I-AI)은 기질 분자내 입체 중심의 절대 배열이 $I:\;C_{1'}(R),\;C_2(S)$인 분자를 atom based fit 정렬하였을 경우의 입체장 조건에서 유도되었으며 PLS 분석 결과, 예측성이 ${r^2}_{cv.}(q^2)=0.856)$ 그리고 적합성이 ${r^2}_{ncv.}=0.964)$ 이었다. 모델의 CoMSIA 등고도 상, pOBP와 냄새 분자 사이의 상호작용으로부터 가장 높은 결합 친화력을 나타내는 분자의 구조적 특정들을 이해할 수 있었다.

• The Korean Journal of Physiology and Pharmacology
• /
• 제2권3호
• /
• pp.323-330
• /
• 1998

Tetrahydroisoquinoline (THI) alkaloids can be considered as cyclized derivatives of simple phenylethylamines. Many of them, especially with 6,7-disubstitution, demonstrate a relatively high affinity for catecholamines. Present study examines the pharmacological action of limited series of THI, using rats' isolated atria and aorta. In addition, a $[^3H]$ prazosin displacement binding study with THI compounds was performed, using rat brain homogenates to investigate whether these probes have ?${\alpha}$-adrenoceptor affinity. We also compared the vascular relaxation potency of these probes with dobutamine. YS 49, YS 51, higenamine and dobutamine, concentration-dependently, relaxed endothelium-denuded rat thoracic aorta precontracted with phenylephrine (PE, 0.1 ${\mu}M$) in which $pEC_{50}$ were $5.56{\pm}0.32$ and $5.55{\pm}0.21$, $5.99{\pm}1.16$ and $5.57{\pm}0.34$, respectively. These probes except higenamine also relaxed KCl (65.4 mM)-contracted aorta. In isolated rat atria, all THIs and dobutamine increased heart rate and contractile force. In the presence of propranolol, the concentration response curves of YS 49 and YS 51 shifted to the right and resulted in $pA_2$ values of $8.07{\pm}0.84$ and $7.93{\pm}0.11$, respectively. The slope of each compound was not deviated from unity, indicating that these chemicals are highly competitive at the cardiac ?${\beta}-adrenoceptors$. YS 49, YS 51, and higenamine showed ?${\alpha)-adrenoceptor$ affinity in rat brain, in which the dissociation constant $(K_i)$ was 2.75, 2.81, and 1.02 ${\mu}M$, respectively. It is concluded, therefore, that THI alkaloids have weak affinity to ${\alpha)_1-adrenoceptor$ in rat aorta and brain, respectively, while these probes show relatively high affinity for cardiac ${\beta}-adrenoceptors$. Thus, these chemicals may be useful in the treatment of congestive heart failure.

• The Korean Journal of Physiology and Pharmacology
• /
• 제1권6호
• /
• pp.769-774
• /
• 1997

Non-neuronal high affinity binding sites for benzodiazepines have been found in many peripheral tissues including cardiac muscle and vascular smooth muscle, and have been designated as 'peripheral benzodiazepine receptor'. Benzodiazepines have been shown to induce relaxation of the ileal, vesical, and uterine smooth muscles. However, it is still unclear about possible involvement of peripheral benzodiazepine receptor on the contractility of trachealis muscle. This study was performed to investigate the role of the peripheral benzodiazepine receptor on the contractility of canine trachealis muscle. Canine trachealis muscle strips of 15 mm long were suspended in an isolated organ bath containing 1 ml of physiological salt solution maintained at $37^{\circ}C$, and aerated with $95%\;O_2/5%\;CO_2$. Isometric myography was performed, and the results of the experiments were as follows: Ro5-4684, FGIN-1-27 and clonazepam reduced a basal tone of isolated canine trachealis muscle strip concentration dependently, relaxant actions of RoS-4684 and FGIN-1-27 were antagonized by PK11195, a peripheral benzodiazepine receptor antagonist. Flumazenil, a central type antagonist, did not antagonize the relaxant action of Peripheral type agonists. Saturation binding assay of [3H]Ro5-4864 showed a high affinity$(Kd=5.33{\pm}1.27nM,\;Bmax=\;867.3{\pm}147.2\;fmol/mg\;protein)$ binding site on the canine trachealis muscle. Ro 5-4684 suppressed the bethanechol-, 5-hydroxyoyptamine- and histamine- induced contractions. Platelet activating factor (PAF) exerted strong and prolonged contraction in trachealis muscle strip. Strong tonic contraction by PAE was attenuated by Ro 5-4684, but not by WEB 2086, a PAF antagonist. Based on these results, it is concluded that the peripheral benzodiazepine receptor mediates the inhibitory regulation of contractilty of canine trachealis muscle.

• Advances in Traditional Medicine
• /
• 제8권3호
• /
• pp.228-235
• /
• 2008

This study was conducted to evaluate the estrogen activity of silkworm (Bombyx mori) pupa extracts and their fractions. Powdered samples of freeze-dried silkworm pupa were extracted at room temperature (RT), $40^{\circ}C$, $60^{\circ}C$, $80^{\circ}C$, and $100^{\circ}C$ in water (D.W), chloroform, ethyl acetate, and methanol for 6h and then filtered (0.45 um). The extracts were then freeze-dried. The estrogenic activity of these extracts was then investigated by competition binding assays using estrogen receptor ${\alpha}\;(ER{\alpha})$ and $ER{\beta}$, and by evaluating their effects on the proliferation of the human breast cancer cell line, MCF-7. Among the extracts evaluated, water extracts prepared at RT showed the highest binding affinity to $ER{\alpha}$ ($IC_{50}$, 1.76 ug/ml) and $ER{\beta}$ ($IC_{50}$, 0.07 ug/ml). In addition, MCF-7 cells that were treated with 62.5 ug/ml of the RT extract showed the greatest increase in proliferation (2-fold; 1291.79%) when compared to control cells (659.82%). Next, the water extract that was prepared at RT (sample 1) was dissolved in D.W. and further fractionated using a Dowex 50W - 8X ($H^+$) column. The flow-through and wash were then pooled together and freeze-dried (sample 2). The bound materials were then eluted with 20 mM NaCl, after which they were applied to a Dowex 1X2 - 200 ($Cl^-$) column and washed with D.W. to remove the sodium ions. The eluants were then freeze-dried (sample 3). Of these fractions, sample 2 showed the highest binding affinity to ER{\alpha} ($IC_{50}$, 1.44 ug/ml) and $ER{\beta}$ ($IC_{50}$, 1.18 ug/ml). In addition, MCF-7 cells that were treated with sample 2 (15.6 ug/ml) showed the largest increase in growth (1159.39%) when compared to control cells (525.26%). Taken together, these results suggest that the fraction of the RT water extract of silkworm pupa referred to as sample 2 may be useful as a phytoestrogen.