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Synthesis and biological evaluation of the mimics of cis ligand for CD22
Yuki Sugamuna,Naoko Matsubara,Yuki Iwayama,Akiharu Ueki,Akihiro Imamura,Hiromune Ando,Takeshi Tsubata,Hideharu Ishida,Makoto Kiso 한국당과학회 2012 한국당과학회 학술대회 Vol.2012 No.1
CD22 (siglec-2) is an accessory molecule of the B-cell receptor complex (BCR) that exertsnegative effects on receptor signaling. It is also well-documented that CD22 is a regulatoryprotein that sets a threshold for immune responses. The carbohydrate ligand recognized byCD22 is the sequence Neuα(2,6)Galβ(1,4)GlcNAc found on both neighboringglycoconjugate of the same cell (cis ligand) and on other cells that interact with B cells (transligands). Recently, we have reported that the C-9 amido derivative of sialic acid (GSC718;9-(4’-hydroxy-4-biphenyl)acetamido-9-deoxy-Neu5Gc-OBn) show a potent affinity andselectivity for CD22 than other siglecs such as MAG [1]. Moreover, the compoundpromoted the proliferation of B cells in vitro. As next step of our investigation, we intend toreinforce the promoting activity of GSC718 for B cell growth by chemical modification.Herein, we report the efficient synthesis of GSC718 analogs which have varied aglyconmoieties. To achieve the comprehensive synthesis of GSC718 analogs having varied aglycons, wereexamined every synthetic process to obtain a fine target compound. In case of thesialoside synthesis, the most time-consuming and troublesome process is thechromatographic separation of α-sialoside from other byproducts such as β−isomer, 2,3-enederivative etc. after glycosylation reaction with aglycon part. To improve this process, weemployed 1,5-lactam formation as the key step for separation because the lactam formation isknown to proceed only in α-sialoside [2]. At the beginning of the synthesis of targetmolecules, we synthesized a suitably modified sialic acid donor in good yields. Then, thesialyl donor was reacted with various 2-substituted-ethanols to give the mixtures of α- and β-glycosides and 2,3-ene derivative, which were subsequently advanced to 1,5-lactamformation. As we anticipated, 1,5-lactamized α-sialosides became isolable from themixtures due to its different polarity from the other byproducts. Finally, the obtained 1,5-lactamized silaosides were successfully converted into target structures via reaction sequenceincluding C9-midification with biphenyl amide group, lactam opening and globaldeprotection. The synthesized analogs were advanced to biological assay using B cells. In this poster presentation, we will also discuss the structure-activity relationships of thesynthesized analogs. [1] H. H. M. Abdu-Allah et al, Bioorg. Med. Chem. Lett. 2011, 19, 1966-1971. [2] H. Tanaka et al, Tetrahedron Lett. 2009, 50, 4478-4481.
Finding Error Data for Linear Separable Model
Yuki Ota,Masahiro Tanaka 제어로봇시스템학회 2009 제어로봇시스템학회 국제학술대회 논문집 Vol.2009 No.8
In this paper, we consider determination of separating hyperplane where some data points are treated as noise. Pocket algorithm with ratchetis an algorithm for this kind of problems, but it does not guarantee minimal number of noisy instances. By noticing that a hyperplane can be determined by selectingn points among data(where n is the dimension of the data), we can guarantee that point. Actually, we found that the second and the third category of iris data is linearly separable by admitting only one instance of noisy data.
Dynamic Quantizers for SIMO Control Systems with Unstable Zeros
Yuki Minami,Shun-ichi Azuma,Toshiharu Sugie 제어로봇시스템학회 2009 제어로봇시스템학회 국제학술대회 논문집 Vol.2009 No.8
In this paper, we present multirate sampling type dynamic quantizers for linear control systems with discrete-valued signal constraints. Although our previous works have derived an optimal dynamic quantizer and verified its effec-tiveness by simulations and experiments, the result can not be applied to SIMO plants with unstable zeros. This paper over comes the draw back by using a multirate sampling technique. We first for mulate an optimal design problem for a class of multirate sampling type dynamic quantizers, and then we give a closed form solution to the problem.
Yuki Ichinose,Takafumi Nishimura,Minori Harada,Ryota Kashiwagi,Mikihiro Yamamoto,Yoshiteru Noutoshi,Kazuhiro Toyoda,Fumiko Taguchi,Daigo Takemoto,Hidenori Matsui 한국식물병리학회 2020 Plant Pathology Journal Vol.36 No.2
Pseudomonas syringae pv. tabaci 6605 has two mul- tidrug resistance (MDR) efflux pump transporters, MexAB-OprM and MexEF-OprN. To understand the role of these MDR efflux pumps in virulence, we generated deletion mutants, ∆mexB, ∆mexF, and ∆mexB∆mexF, and investigated their sensitivity to plant-derived antimicrobial compounds, antibiotics, and virulence. Growth inhibition assays with KB soft agar plate showed that growth of the wild-type (WT) was inhibited by 5 μl of 1 M catechol and 1 M coumarin but not by other plant-derived potential antimicrobial compounds tested including phytoalexins. The sensitiv- ity to these compounds tended to increase in ∆mexB and ∆mexB∆mexF mutants. The ∆mexB∆mexF mutant was also sensitive to 2 M acetovanillone. The mexAB- oprM was constitutively expressed, and activated in the ∆mexF and ∆mexB∆mexF mutant strains. The swarming and swimming motilities were impaired in ∆mexF and ∆mexB∆mexF mutants. The flood inocula- tion test indicated that bacterial populations in all mu- tant strains were significantly lower than that of WT, although all mutants and WT caused similar disease symptoms. These results indicate that MexAB-OprM extrudes plant-derived catechol, acetovanillone, or cou- marin, and contributes to bacterial virulence. Further- more, MexAB-OprM and MexEF-OprN complemented each other’s functions to some extent.
Design of Model Following Control Systems with Discrete-valued Signal Constraints
Yuki Minami 제어·로봇·시스템학회 2016 International Journal of Control, Automation, and Vol.14 No.1
This paper focuses on a design problem of model following control systems with discrete-valued inputconstraints. In the problem, we design a discrete-valued output controller such that the output behavior of thediscrete-valued input system is similar to that of a given reference model. In this paper, we first formulate thecontroller design problem, and then we analyze the performance of a class of controllers. Based on the result ofthe performance analysis, we analytically derive a controller characterized by the parameters of the plant and thereference model. Finally, we discuss a practical controller design problem considering the fixed-order, the stability,and the input-output gain constraints of controllers. The problem is solved by using a particle swarm optimizationalgorithm.