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141.
Tamaki M Harada T Fujinuma K Takanashi K Shindo M Kimura M Uchida Y 《Chemical & pharmaceutical bulletin》2012,60(6):743-746
To find candidates with high antimicrobial and low hemolytic activities, many gratisin (GR) analogues have been designed and synthesized. In the present account, we synthesized novel derivatives of GR having both the polycationic and fatty acyl groups, cyclo{-Val(1)-Orn(2)-Leu(3)-D-Phe(4)-Pro(5)-D-Lys(6)(X)-Val(7)-Orn(8)-Leu(9)-D-Phe(10)-Pro(11)-D-Lys(12)-} {X=-CO(CH(2))(6)CH(3) (1), -Lys-CO(CH(2))(6)CH(3) (2), -(Lys)(2)-CO(CH(2))(6)CH(3) (3), and -(Lys)(3)-CO(CH(2))(6)CH(3) (4)}, and examined the biological activities. Among them, we found that 2-4 have differential ionic interaction against the prokaryotic membrane and eukaryotic membrane. In other words, the dissociation with high antimicrobial activity and low hemolytic activity is caused by the addition of D-Lys(6)-{(Lys)(n)-CO(CH(2))(6)CH(3)} residues at position 6 of [D-Lys(6,12)]-GR. Our findings should be helpful in finding drug candidates with high antimicrobial activity and low hemolytic activity that are capable of combating microbial resistance. 相似文献
142.
Yoshiki K. Tanaka Stefan Friedrich Hiroyuki Fujioka Hans Geissel Ryugo S. Hayano Satoru Hirenzaki Kenta Itahashi Satoshi Itoh Daisuke Jido Volker Metag Hideko Nagahiro Mariana Nanova Takahiro Nishi Kota Okochi Haruhiko Outa Ken Suzuki Takatoshi Suzuki Helmut Weick 《Few-Body Systems》2013,54(7-10):1263-1266
We are going to perform an inclusive spectroscopy experiment of η′ mesic nuclei with the 12C(p,d) reaction to study in-medium properties of the η′ meson. In nuclear medium, the η′ meson mass may be reduced due to partial restoration of chiral symmetry. In case of sufficiently large mass reduction and small absorption width of η′ at normal nuclear density, peak structures of η′ mesic states in 11C will be observed near the η′ emission threshold even in an inclusive spectrum. The experiment will be carried out at GSI with proton beam supplied by SIS using FRS as a spectrometer. The detail of the experiment is described. 相似文献
143.
Addition reaction of photo-generated radicals to double bonds of diethyl fumarate (deF) and diethyl maleate (deM), which are geometrical isomers, was studied by means of time-resolved- (TR-) and pulsed-electron paramagnetic resonance (EPR). Analysis of TR-EPR spectra indicates that adduct radicals from deF and deM should have the same structure. The double bonds of these monomers are converted to single ones by addition reaction, which allows hindered internal rotation to give the same structure of adduct radical. The rate constants for addition reaction of photo-generated radicals were determined by Stern–Volmer analysis of the decay time of electron spin-echo intensity of these radicals measured by the pulsed EPR method. Rate constants for deF were found to be larger than those for deM. This relation is in good consistent with efficiency of polymerisation of deF and deM. Experimentally determined rate constants were evaluated by introducing the addition reaction model on the basis of two important factors enthalpy and polar effects. 相似文献
144.
Kenta Watanabe 《Semigroup Forum》2013,86(2):395-403
Let X be a K3 surface with Picard number one which is given by a double cover π:X→?2. Let C be a smooth curve on X with π ?1 π(C)=C which is not the ramification divisor of π, and let P be a ramification point of π| C :C→π(C). In this paper, in the case where the intersection multiplicity at π(P) of the curve π(C) and the tangent line at π(P) on π(C) is equal to deg(π(C)) or deg(π(C))?1, we investigate the Weierstrass semigroup of the pointed curve (C,P). 相似文献
145.
Let G be a graph. We denote p(G) and c(G) the order of a longest path and the order of a longest cycle of G, respectively. Let κ(G) be the connectivity of G, and let σ 3(G) be the minimum degree sum of an independent set of three vertices in G. In this paper, we prove that if G is a 2-connected graph with p(G) ? c(G) ≥ 2, then either (i) c(G) ≥ σ 3(G) ? 3 or (ii) κ(G)?=?2 and p(G) ≥ σ 3(G) ? 1. This result implies several known results as corollaries and gives a new lower bound of the circumference. 相似文献
146.
147.
Toshiyuki Takayanagi Kenta Takahashi Akira Kakizaki Motoyuki Shiga Masanori Tachikawa 《Chemical physics》2009
Path-integral molecular dynamics simulations for the HCl(H2O)4 cluster have been performed on the ground-state potential energy surface directly obtained on-the-fly from semiempirical PM3-MAIS molecular orbital calculations. It is found that the HCl(H2O)4 cluster has structural rearrangement above the temperature of 300 K showing a liquid-like behavior. Quantum mechanical fluctuation of hydrogen nuclei plays a significant role in structural arrangement processes in this cluster. 相似文献
148.
The time‐dependent emission enhancement (TDEE) phenomena of the 1‐(o‐carboran‐1‐yl)ethynylpyrene dyad were reported. It was found that the emission intensity from the dyad increased in tetrahydrofuran (THF), acetone and dichloromethane with increasing incubation time. From the mechanistic studies, it was suggested that agglomeration of the dyad gradually proceeded in these media, followed by expression of excimer luminescence. Additionally, it was shown that the rates of TDEE of the dyad were sensitively accelerated in the presence of a trace amount of water. Based on this fact, a detection system for water contents in acetone was constructed. Before and after incubation for 96 h at room temperature, time courses of changes in optical properties were monitored. Finally, water contents in acetone can be estimated by the degrees of TDEE and emission color changes in the range from 0.1 wt % to 2.0 wt % and from 2.0 wt % to 20 wt %, respectively. 相似文献
149.
150.
Hiroyuki Yamazaki Akiho Yagi Masanari Akaishi Ryota Kirikoshi Ohgi Takahashi Tatsuki Abe Satomi Chiba Kenta Takahashi Natsuki Iwakura Michio Namikoshi Ryuji Uchida 《Tetrahedron letters》2018,59(20):1913-1915
A new cladosporol derivative, 2-chloro-cladosporol D (6), was isolated together with known cladosporol (1), cladosporols B–D (2–4), and cladosporol F (5) from the culture broth of plant-associated Cladosporium sp. TMPU1621. The structure of 6 was elucidated from spectroscopic analyses including NMR and MS data. The productivity of 6 increased in 3% NaCl-supplemented medium; therefore, fermentation of the producing fungus TMPU1621 with 3% NaBr was investigated, leading to the induced production of a new halogenated cladosporol, 2-bromo-cladosporol D (7). Compound 2 showed the lowest MIC values of 3.13 and 12.5?μg/mL against two MRSA strains, ATCC43300 and ATCC700698, respectively. 相似文献