• Journal of Microbiology and Biotechnology
• /
• 제22권1호
• /
• pp.46-49
• /
• 2012

The Vibrio vulnificus vuuA gene, of which expression is repressed by a complex of iron and ferric uptake regulator (Fur), was characterized to localize the Fur-binding site in its upstream regulatory region. In silico analysis suggested the presence of two possible Fur-binding sites; one is a classical Fur-box and the other is a previously reported distinct Fur-binding site. Site-directed mutagenesis and DNase I protection assays revealed the binding site for the iron-Fur complex, which includes an extended inverted repeat containing a homologous sequence to the classical Fur-box.

• Archives of Pharmacal Research
• /
• 제10권3호
• /
• pp.184-187
• /
• 1987

ln order to develope anti-inflammatory glucocorticoids for local use without systemic side-effects, ester and amide derivatives of 20$\xi$-dihydroprednisolonic acid have been prepared. When binding affinities of these compounds to glucocorticoid receptor of rat liver cytosol were compared, all a-isomer at C-20 showed higher binding affinities than the corres¬ponding $\beta$-isomer. The size of the substituents at C-21 had significant influences on binding affinities, which were related with their lipophilicity.

• Bulletin of the Korean Chemical Society
• /
• 제30권11호
• /
• pp.2717-2722
• /
• 2009

The use of the classification and regression tree (CART) methodology was studied in a quantitative structure-activity relationship (QSAR) context on a data set consisting of the binding affinities of 39 imidazobenzodiazepines for the α1 benzodiazepine receptor. The 3-D structures of these compounds were optimized using HyperChem software with semiempirical AM1 optimization method. After optimization a set of 1481 zero-to three-dimentional descriptors was calculated for each molecule in the data set. The response (dependent variable) in the tree model consisted of the binding affinities of drugs. Three descriptors (two topological and one 3D-Morse descriptors) were applied in the final tree structure to describe the binding affinities. The mean relative error percent for the data set is 3.20%, compared with a previous model with mean relative error percent of 6.63%. To evaluate the predictive power of CART cross validation method was also performed.

• 대한약리학회지
• /
• 제31권2호
• /
• pp.219-231
• /
• 1995

Vasoactive intestinal polypeptide(VIP) and ${\beta}-adrenergic$ agonists have immunomodultory effects on the peripheral blood T-lymphocytes of rat through their own receptors. Both of them utilize the same signal transduction pathway. That is, the stimulatory guanine nucleotide binding protein(G protein) mediates the receptor-adenylyl cyclase coupling, producing intracellular increase of cyclic adenosine monophosphate(cAMP). In the previous experiment, propranolol, a ${\beta}-adrenergic$ receptor blocker, inhibited the VIP-induced protein phosphorylation in lymphocytes. However, propranolol could not block the effect induced by forskolin. Therefore, this study was designed to elucidate the mechanism of the inhibitory action of propranolol on the effects of VIP. Using peripheral blood lymphocytes of rats, the effect of propranolol on the receptor binding characteristics of VIP was observed. And the effects of propranolol were compared to the effects of timolol on the cAMP increase induced by isoproterenol, VIP or forskolin. The results obtained are as follows. 1) Receptor binding study showed no significant differences in the affinity or density of VIP receptor between the control and propranolol-pretreated groups. 2) VIP-induced increase of cAMP was inhibited by propranolol, but not by timolol. 3) Both propranolol and timolol suppressed the isoproterenol-induced cAMP increase. 4) Propranolol also inhibited the histamine-induced cAMP increase. 5) Propranolol did not inhibit the increase of cAMP stimulated by forskolin. 6) Lidocaine did not block the VIP-induced cAMP increase. These results show that the inhibitory mechanism of propranolol is not related to ${\beta}-adrenergic$ receptor or its membrane stabilizing effect, and it is suggested that propranolol can block the effects of VIP by inhibiting the intermediate step between the VIP receptor and adenylyl cyclase.

• 약학회지
• /
• 제36권3호
• /
• pp.220-229
• /
• 1992

The muscarinic acetylcholine receptors of the dog unpregant uterus were characterized using $[^3H]quinuclidinyl$ benzilate(QNB) as a radioligand and the binding of muscarinic receptor agonists and antagonists in the uterus was compared to that in the urinary bladder which contains almost exclusively the M2 receptors in order to determine the receptor subtypes in the uterus. $[^3H]QNB$ binding to uterus and bladder was rapid, saturable and reversible. Scatchard analysis of the saturation data gave linear plots and the Hill coefficients were close to unit, which indicated that each preparation contained a single population of specific binding sites for $[^3H]QNB$. The KD values(120 pM) for QNB were almost identical in both organs, whereas the $B_{max}$ value of 256 fmol/mg protein in the uterus was significantly different from that of 563 fmol/mg protein in the bladder. Muscarinic agonists and antagonists inhibited in a competitive manner the $[^3H]QNB$ binding to the same extent in both organs. The competition binding studies using antagonists(atropine and pirenzepine) exhibited a single binding site and this site had a low affinity for pirenzepine with the Ki value of about 330 nM. However, high and low affinity binding sites were observed with carbachol, methacholine and oxotremorine. These binding studies with agonists and antagonists did not show any differences in drug affinities between uterus and bladder. These results indicate that the muscarinic receptors in the uterus are M2 receptors which have a low affinity for pirenzepine.

• 대한약리학회지
• /
• 제19권2호
• /
• pp.57-67
• /
• 1983

Guinea-Pig의 myenteric plexus-longitudinal muscle preparation에서 morphine과 naloxone 효과(效果)에 미치는 전해질(電解質)의 영향(影響)을 관찰(觀察)하였다. 표본(標本)은 Krebs-Henseleit bicarbonate tufter solution 으로 채운 organ bath에 현수(懸垂)하고 0.2Hz로 전기자극(電氣刺戟)하였다. Morphine은 전기자극(電氣刺戟)에 의(依)한 근편수축(筋片收縮)을 억제(抑制)하였으며, 이때 $ID_{30}$은 약(約) 190nM이었다. 이와같은 morphine의 억제작용(抑制作用)은 bath내(內) $Na^+$ 또는 $K+$ 농도(濃度)를 감소(減少)시키거나 $Mg^{2+}$을 가(加)하면 강화(强化)되었으며, $Ca^{2+}$ 농도(濃度)를 증가(增加)시키거나 $Mg^{2+}$를 농도(濃度)를 감소(減少)시키면 약화(弱化)되었다. Naloxone은 morphine의 작용(作用)을 억제(抑制)하였으며, 이때 naloxone에 대(對)한 affinity index인 $pA_2$ value는 약(約) 8.8이었고 that내(內) 전해질(電解質) 농도(濃度)를 변동(變動)시켜도 영향(影響)받지 않았다. 이 성적(成積)은 전해질(電解質) 변동(變動)으로 인(因)한 morphine의 작용변동(作用變動)은 전해질(電解質)이 opiate receptor의 affinity를 변동(變動)시킨다는 opiate-receptor binding실험(實驗)에서와는 달리 전해질(電解質) 변동(變動)에 의(依)한 functional opiate receptor의 affinity 변동(變動)에 의(依)한 것이 아님을 시사(示唆)한다.

• 한국응용약물학회:학술대회논문집
• /
• 한국응용약물학회 1994년도 춘계학술대회 and 제3회 신약개발 연구발표회
• /
• pp.305-305
• /
• 1994

It has been shown that there are several subtypes of $\kappa$ opioid receptor, We have evaluated the properties of non-${\mu}$, non-$\delta$ binding of 〔$^3$H〕DIP, a nonselective opioid antagonist, in rat cortex membranes. Binding to ${\mu}$ and $\delta$ sites was inhibited by the use of an excess of competing selective agonists (DAMGO, DPDPE) for these sites. (-)Ethylketocyclazocine(EKC) inhibited 〔$^3$H〕DIP binding with Ki. of 70 nM. However, arylacetamides (U69593 and U50488H) gave little inhibition. Also, we have examined the opioid modulation of K$\^$+/(30 mM)-induced histamine release in rat frontal cortex slices labeled with 1-〔$^3$H〕histidine. The 〔$^3$H〕histamine release from cortex slices was inhibited by EKC, a $\kappa$$_1$-and $\kappa$$_2$-agonist, in a concentration-dependent manner(10 to 10,000 nM). The IC$\sub$50/ of EKC was 107 ${\pm}$ 6 nM. However, the $\delta$ receptor selective agonists, DPDPE and deltorphine II, ${\mu}$ receptor agonists, DAMGO and TAPS, $\kappa$$_1$-agonists, U69593 and U50488H, and $\varepsilon$-agonist, ${\beta}$-endorphin, did not inhibit histamine release even in micromoiar dose, indicating that ${\mu}$, $\delta$ or $\kappa$$_1$ receptors are not involved. The concentration-response curve of EKC was shifted to right in the presence of naloxone (300 nM), a ${\mu}$ preferential antagonist, norbinaltorphimine(300 nM), a $\kappa$$_1$ preferential antagonist and bremazocine(1 nM), a $\kappa$$_1$-agonist and $\kappa$$_2$-antagonist. These results suggest that $\kappa$$_2$ opioid receptor regulates histamine release in the frontal cortex of the rat.

• Clinical and Experimental Reproductive Medicine
• /
• 제13권2호
• /
• pp.187-193
• /
• 1986

The purpose of this study was to establish optimal conditions for progesterone receptor assay using rat uterus, therby applying this system to understand action mechanism of progesterone in female reproductive organ and to evaluate physiological and pathological conditions in female reproduction. The results obtained were as follows 1. $^3H-R5020$ seemed to be more stable than 3H-progesterone as a ligand. 2. Optimal incubation time for ligand and receptor binding was 4-5 hrs at $4^{\circ}C$. 3. For the separation of bond and free ligand, optimal charcoal incubation time was 20 mins. 4. 2-3 mg cytosolic protein/ml was optimal for the binding of ligand. 5. Endogenous progesterone did not influence binding of ligand and receptor unless endogenous progesterone levels were extremely high as in case of pregnancy. 6. Dissociation rate for progesterone receptor was 1.22 nM. 7. $^3H-R5020$ did not bind to corticoid binding globulin (CBG), suggesting that addition of cortisol is saturate CBG was, not necessary as far as $^3H-R5020$ was used as a radioligand. It is, therefore, considered that this assay system established with these conditions might be used for the research as well as clinical routine purposes.

• 한국환경성돌연변이발암원학회지
• /
• 제22권3호
• /
• pp.175-182
• /
• 2002

Endocrine disruptors (EDs) are the chemicals that affect endocrine systems through activation or inhibition of steroid hormone response. It is necessary to have a good system to evaluate rapidly and accurately endocrine-disrupting activities of suspected chemicals and their degradation products. The key targets of EDs are nuclear hormone receptors, which bind to steroid hormones and regulate their gene transcription. We constructed a co-expression system of Gal4p DNA binding domain (DBD)- ligand binding domain of human estrogen receptor $\alpha$ or $\beta$, and Gal4p transactivation domain (TAD)-co-activator AIB-1, SRC-1 or TIF-2 in Saccharomyces cerevisiae with a chromosome-integrated lacZ reporter gene under the control of CYC1 promoter and Gal4p binding site (GAL4 upstream activating sequence, GAL4$_{UAS}$). Expression of this reporter gene was dependent on the presence of estrogen or EDs in the culture medium. We found that the two-hybrid system with combination of the hER$\beta$ LBD and co-activator SRC-1 was most effective in the xenoestrogen-dependent induction of reporter activity. The extent of transcriptional activation by those chemicals correlated with their estrogenic activities measured by other assay systems, indicating that this assay system is efficient and reliable for measuring estrogenic activity. The data in this research demonstrated that the yeast detection system using steroid hormone receptor and co-activator is a useful tool for identifying chemicals that interact with steroid receptors.s.

• Clinical and Experimental Reproductive Medicine
• /
• 제16권2호
• /
• pp.131-138
• /
• 1989

The present study was designed to develop a new method for the determination of estrogen receptor in porcine uterus using frozen sections. Cryostat sections were incubated with $^3H$-estradiol($^3H$-$E_2$) in the presence or absence of diethylstilbestrol(DES) and the radioactivity of 3H-E2 bound to estrogen receptor(ER) was detected. The level of specific estrogen receptor was determined by Scatchard analysis. The highest ratio of specific binding against total binding was achieved in 3 sec. tions(5mm x 5mm) which was corresponded to lOO${\mu}$/ml protein concentration. Optimal binding was obtained during incubation with $^3H$-$E_2$ for 30 minutes at 23$^{\circ}C$ after treatment of sections with acetone for 20 seconds. Three time-washing of sections was proved to be appropriate for the removal of unbound 3H-E2. 200-fold molar excess of DES was substituted for the binding of $^3H$-$E_2$ to ER sufficiently(binding efficiency of 54.8%). ER was saturated with 4nM of $^3H$-$E_2$ and its dissociation constant was 0.1nM. ER assay using frozen sections(Histological radioreceptor assay, HRRA) was significantly correlated with radioreceptor assay for estradiol(RRA, 0.976 , p