• BMB Reports
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• 제40권6호
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• pp.1058-1068
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• 2007

The post-translational modifications of Ser and Thr residues by O-linked $\beta$-N-acetylglucosamine (O-GlcNAc), i.e., O-GlcNAcylation, is considered a key means of regulating signaling, in a manner analogous to protein phosphorylation. Furthermore, it has been suggested that the increased flux of glucose through the hexosamine biosynthetic pathway (HBP) stimulates O-GlcNAcylation, and that this may be responsible for many of the manifestations of type 2 diabetes mellitus. To determine whether excessive O-GlcNAcylation of target proteins results in pancreatic $\beta$ cell dysfunction, we increased nucleocytoplasmic protein O-GlcNAcylation levels in $\beta$ cells by exposing them to streptozotocin and/or glucosamine. Streptozotocin and glucosamine co-treatment increased O-GlcNAcylated proteomic patterns as assessed by immunoblotting, and these increases in nuclear and cytoplasmic protein O-GlcNAcylations were accompanied by impaired insulin secretion and enhanced apoptosis in pancreatic $\beta$ cells. This observed $\beta$cell dysfunction prompted us to examine Akt and Bcl-2 family member proteins to determine which proteins are O-GlcNAcylated under conditions of high HBP throughput, and how these proteins are associated with $\beta$ cell apoptosis. Eventually, we identified ten new O-GlcNAcylated proteins that were expressed during $\beta$ cell apoptosis, and analyzed the functional implications of these proteins in relation to pancreatic $\beta$ cell dysfunction.

• 한국식품과학회지
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• 제24권6호
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• pp.568-573
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• 1992

일반계(신선찰벼)와 통일계(한강찰벼) 찹쌀전분의 분자구조적 성질을 조사한 결과 이화학적 성질과 열수가용성 전분의 함량은 큰 차이가 없었다. 전분의 사슬길이와 바깥사슬길이는 한강찰벼가, 안쪽사슬길이는 신선 찰벼가 길었으나, ${\beta}-amylase$ 분해한도는 비슷하였다. 찹쌀전분을 ${\beta}-amylase$로 처리하고 겔크로마토그래피한 결과는 서로 비슷하였으나 pullulanase를 처리하였을 때는 용출패턴에 차이를 보였다. 산처리 2일째의 시료의 ${\beta}-amylase$ 분해한도는 한강찰벼가 $2{\sim}3%$ 높았으나 두 시료 모두 산가수분해시간에 따라 직선적으로 증가하였다. 산처리 시료를 ${\beta}-amylase$ 또는 pullulanase로 처리했을 때 겔크로마토그래피의 용출패턴은 생전분과는 크게 달랐다.

• Journal of Ginseng Research
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• 제36권2호
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• pp.153-160
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• 2012

Panax ginseng has long been used as a traditional herbal medicine. More recently, it has received attention for its anti-diabetic and anti-obesity effects in humans and in animal models of type 2 diabetes. In the present study, we tested the hypoglycemic effects of ginseng berry extract in beta-cell-deficient mice and investigated the mechanisms involved. Red (ripe) and green (unripe) berry extracts were prepared and administered orally (100 or 200 mg/kg body weight) to streptozotocin-induced diabetic mice daily for 10 wk. The body weight was measured daily, and the nonfasting blood glucose levels were measured after 5 and 10 wk after administration. Glucose tolerance tests were performed, and the serum insulin levels were measured. The proliferation of beta-cells was measured in vitro. The administration of red or green ginseng berry extract significantly reduced the blood glucose levels and improved the glucose tolerance in beta-cell deficient mice, with the higher doses resulting in better effects. Glucose-stimulated insulin secretion was significantly increased in berry extract-treated mice compared with streptozotocin-induced diabetic control mice. Treatment with ginseng berry extract increased beta-cell proliferation in vitro. Both red berry and green berry extracts improved glycemic control in streptozotocin-induced diabetic mice and increased insulin secretion, possibly due to increased beta-cell proliferation. These results suggest that ginseng berry extracts might have beneficial effects on beta-cell regeneration.

• Molecules and Cells
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• 제38권1호
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• pp.20-25
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• 2015

TGF-${\beta}$ regulates pleiotropic cellular responses including cell growth, differentiation, migration, apoptosis, extracellular matrix production, and many other biological processes. Although non-Smad signaling pathways are being increasingly reported to play many roles in TGF-${\beta}$-mediated biological processes, Smads, especially receptor-regulated Smads (R-Smads), still play a central mediatory role in TGF-${\beta}$ signaling for epithelial-mesenchymal transition. Thus, the biological activities of R-Smads are tightly regulated at multiple points. Inhibitory Smad (I-Smad also called Smad7) acts as a critical endogenous negative feedback regulator of Smad-signaling pathways by inhibiting R-Smad phosphorylation and by inducing activated type I TGF-${\beta}$ receptor degradation. Roles played by Smad7 in health and disease are being increasingly reported, but the molecular mechanisms that regulate Smad7 are not well understood. In this study, we show that E3 ubiquitin ligase Itch acts as a positive regulator of TGF-${\beta}$ signaling and of subsequent EMT-related gene expression. Interestingly, the Itch-mediated positive regulation of TGF-${\beta}$ signaling was found to be dependent on Smad7 ubiquitination and its subsequent degradation. Further study revealed Itch acts as an E3 ubiquitin ligase for Smad7 polyubiquitination, and thus, that Itch is an important regulator of Smad7 activity and a positive regulator of TGF-${\beta}$ signaling and of TGF-${\beta}$-mediated biological processes. Accordingly, the study uncovers a novel regulatory mechanism whereby Smad7 is controlled by Itch.

• 접착 및 계면
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• 제13권4호
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• pp.163-170
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• 2012

${\beta}$-cyclodextrin은 다른 분자를 포접하여 inclusion complex (포접착물)를 만드는 특성을 가지고 있기 때문에 의약품, 농약, 식품, 화장품, 산화방지제, 휘발방지제, 흡습방지제, 퇴색방지제, 유화제 등의 다양한 용도로 사용되고 있다. 이러한 장점에도 불구하고 ${\beta}$-cyclodextrin은 물이나 유기용매에 대한 용해도가 낮아 사용에 제약을 받아왔다. 본 연구에서는 이러한 문제를 해결하기 위해서 Bisphenol-A나 폴리우레탄(PU) 발포제인 cyclopropane에 대한 포접특성을 갖고 물이나 유기용매에 대한 용해도가 향상된 polyol type의 ${\beta}$-cyclodextrin 유도체를 합성한 후 그 특성을 고찰하였다. 연구결과 합성된 polyol을 사용해서 제조한 경질 PU foam은 기존의 polyol과 비교해서 더 우수한 열전도 특성과 압축강도를 나타내었다.

• 대한본초학회지
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• 제28권4호
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• pp.49-55
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• 2013

Objectives : Mori Folium was popularly used as one of the traditional medicinal herbs. Although M. Folium has been cultivated for rearing silkworm historically, it's use has been expanded as natural therapeutic agent for the treatment of filariasis, diabetes and dropsy in East Asia. However, little has been known about the effect of M. Folium on liver fibrosis. Therefore, we would like to explore an anti-fibrogenic potential of M. Folium extract (MFE) using immortalized human hepatic stellate cell line, LX-2 cells. Methods : We examined the effects of MFE on the transforming growth factor ${\beta}1$ ($TGF{\beta}1$)-induced liver fibrosis in LX-2 cells. Cell viability, Smad binding element-driven luciferase activity, phosphorylations level of Smad 2/3, and expression level of $TGF{\beta}1$-dependent target genes were monitored in the MFE-treated LX-2 cells. Results : Up to 30 ${\mu}g/ml$ MFE treatment did not show any possible toxic effect in LX-2 cells. MFE inhibited $TGF{\beta}1$-inducible Smad binding element-driven luciferase activity and decreased the $TGF{\beta}1$-inducible phosphorylations of Smad 2 and Smad 3 in hepatic stellate cell in a dose dependent manner. Furthermore, increases of plasminogen activator inhibitor type 1, $TGF{\beta}1$ and matrix metalloproteinases 2 genes by $TGF{\beta}1$ were also attenuated by MFE treatment. Conclusions : These findings suggested that MFE would be used as a potential therapeutic agent for the treatment liver fibrosis, which might be mediated by the inhibition of $TGF{\beta}1$-inducible Smad 2/3 transactivation and target genes expression.

• Bulletin of the Korean Chemical Society
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• 제31권3호
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• pp.689-693
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• 2010

Second-order rate constants ($k_{CN^-}$) have been measured for nucleophilic substitution reactions of Y-substituted phenyl benzoates (1a-r) with $CN^-$ ion in 80 mol % $H_2O$/20 mol % DMSO at $25.0{\pm}0.1^{\circ}C$. The Br${\o}$nsted-type plot is linear with ${\beta}_{1g}$ = -0.49, a typical ${\beta}_{1g}$ value for reactions reported to proceed through a concerted mechanism. Hammett plots correlated with ${\sigma}^{\circ}$ and ${\sigma}^-$ constants exhibit many scattered points. In contrast, the Yukawa-Tsuno plot for the same reaction exhibits excellent linearity with ${\rho}_Y$ = 1.37 and r = 0.34, indicating that a negative charge develops partially on the oxygen atom of the leaving aryloxide in the rate-determining step (RDS). Although two different mechanisms are plausible (i.e., a concerted mechanism and a stepwise pathway in which expulsion of the leaving group occurs at the RDS), the reaction has been concluded to proceed through a concerted mechanism on the basis of the magnitude of ${\beta}_{1g}$ and ${\rho}_Y$ values.

• BMB Reports
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• 제50권11호
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• pp.584-589
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• 2017

Intercellular adhesion molecule-1 (ICAM-1), which is induced by tumor necrosis factor (TNF)-${\alpha}$, contributes to the entry of immune cells into the site of inflammation in the skin. Here, we show that protein tyrosine phosphatase non-receptor type 21 (PTPN21) negatively regulates ICAM-1 expression in human keratinocytes. PTPN21 expression was transiently induced after stimulation with TNF-${\alpha}$. When overexpressed, PTPN21 inhibited the expression of ICAM-1 in HaCaT cells but PTPN21 C1108S, a phosphatase activity-inactive mutant, failed to inhibit ICAM-1 expression. Nuclear factor-${\kappa}B$ (NF-${\kappa}B$), a key transcription factor of ICAM-1 gene expression, was inhibited by PTPN21, but not by PTPN21 C1108S. PTPN21 directly dephosphorylated phospho-inhibitor of ${\kappa}B$ ($I{\kappa}B$)-kinase ${\beta}$ ($IKK{\beta}$) at Ser177/181. This dephosphorylation led to the stabilization of $I{\kappa}B{\alpha}$ and inhibition of NF-${\kappa}B$ activity. Taken together, our results suggest that PTPN21 could be a valuable molecular target for regulation of inflammation in the skin by dephosphorylating p-$IKK{\beta}$ and inhibiting NF-${\kappa}B$ signaling.

• 한국농공학회지
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• 제21권4호
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• pp.108-117
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• 1979

In order to obtain the basic data for design of water structures which can be contributed to the planning of water use. Best fitted distribution function and the equations for the probable minimum flow were derived to the annual minimum flow of five subwatersheds along Geum River basin. The result were analyzed and summarized as follows. 1. Type III extremal distribution was considered as a best fit one among some other distributions such as exponential and two parameter lognormal distribution by $x^2$-goodness of fit test. 2. The minimum flow are analyzed by Type III extremal distribution which contains a shape parameter $\lambda$, a location parameter ${\beta}$ and a minimum drought $\gamma$. If a minimum drought $\gamma=0$, equations for the probable minimum flow, $D_T$, were derived as $D_T={\beta}e^{\lambda}1^{y'}$, with two parameters and as $D_T=\gamma+(\^{\beta}-\gamma)e^{{\lambda}y'}$ with three parameters in case of a minimum drought ${\gamma}>0$ respectively. 3. Probable minimum flow following the return periods for each stations were also obtained by above mentioned equations. Frequency curves for each station are drawn in the text. 4. Mathematical equation with three parameters is more suitable one than that of two parameters if much difference exist between the maximum and the minimum value among observed data.

• 대한약리학회지
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• 제13권2호
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• pp.49-59
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• 1977

Adrenergic receptors are now classified into alpha type and beta type These adrenergic receptors are distributed in various tissue in different patterns. Therefore, the adrenergic response of a certain tissue may be different from those of the other tissues, and such differences may exist among various species of animals. In this paper, the authors attempt to reevaluate the effect of epinephrine on the isolated atria, aortic strips, and vas deferenses of rabbits preincubated with alpha receptor blockades (ergotamine and dibenamine) and beta receptor blockades (propranolol and dichloroisoproterenol) in Locke-Ringer bathing medium. The results obtained were summarized as follows; 1) The dose dependent responses of isolated atria to epinephrine were significantly inhibited by propranolol and dichloroisoproterenol, and slightly inhibited by dibenamine, but not affected by ergotamine. 2) The dose dependent responses of excised aortic strips to epinephrine were significantly inhibited by ergotamine and dibenamine, but the responses were slightly potentiated by propranolol, and significantly by dichloroisoproterenol. 3) The dose dependent responses of isolated vas deferenses to epinephrine were significantly inhibited by ergotamine and dibenamine, but slightly potentiated by propranolol and dichloroisoproterenol.