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81.
82.
Esters of ferulic acid with monoterpene alcohols were found in ponderosa pine oleoresin. These colorless ferulic acid esters are responsible for a yellow band seen on DEAE-Sephadex fractionation of the oleoresin. Two diterpene resin acids not previously found in pines and several resin acid artifacts were identified. 相似文献
83.
The conformation of oligopeptides with hydrophobic side chains, Nps-(L -Leu-L -Leu-L -Ala)n-OEt and Nps-(L -Met-L -Met-L -Leu)n-OEt(n = 1–6), in the solid state, obtained either by evaporation of the solvent or by precipitation with diethyl ether from a 1,1,1,3,3,3-hexafluoropropan-2-ol (HFIP) solution, has been studied with ir spectroscopy and x-ray powder-diffraction measurements. The conformation of these peptides in the HFIP solution has been studied by CD spectroscopy. Due to a strong preference of the amino acids to form an α helix, the peptides begin forming α helices at the dodecapeptide in the HFIP solution, and in the solid state by evaporation. In the solid state, with precipitation, the α-helical conformation is first observed at the octadecapeptide and the lower peptides assume a β structure. The conformational change, from the α helix to the β structure of the peptides with 12 to 15 amino acid residues, during the precipitation process, is due to a strong tendency of the amino acids to form the β-structure in rather short peptide lengths. 相似文献
84.
Conformational Studies of Australia Antigen by Optical Rotatory Dispersion and Circular Dichroism
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Noriyoshi Sukeno Ryoichi Shirachi Hiroyuki Shiraishi Nakao Ishida 《Journal of virology》1972,10(1):157-158
The optical rotatory dispersion and circular dichroism of intact, 8 m urea- or sodium dodecyl sulfate-treated, and carbamidomethylated Australia antigen indicated that the antigen possesses a high alpha-helical content similar to human high-density lipoproteins. 相似文献
85.
Stress relaxation properties of the cell wall of tissue segments under different growth conditions 总被引:1,自引:0,他引:1
Masuda Yoshio; Yamamoto Ryoichi; Kawamura Hideto; Yamagata Yoshiki 《Plant & cell physiology》1974,15(6):1083-1092
Stress-relaxation parameters were compared under different experimentalconditions using 5th internode segments of light-grown pea seedlingsand coleoptile segments of dark-grown Avena seedlings. The followingresults were obtained. 1. In a short incubation period at 25?C, IAA caused a decreasein the minimum relaxation time, To, of the epidermal cell wallof pea internodes when it induced elongation; the optimum concentrationof IAA for decreasing To was 10 mg/liter. 2. At all concentrations of IAA used, 0.11000 mg/liter,the relationship between the To value of the epidermal cellwall peeled from segments incubated for 2 hr and the subsequentelongation rate in 23 hr incubation was linear, indicatingthat the To value of the cell wall at a certain time regulatesthe rate of the following elongation. 3. When segments of pea epicotyls or Avena coleoptiles wereincubated in mannitol solution of various concentrations inthe presence and absence of IAA and then allowed to grow inthe absence of both mannitol and IAA, the segments extendeddifferently depending upon the mannitol concentration, whichwas less than 0.3 M, given during preincubation. 4. The To and b (relaxation rate, S/log t) values were smallerin the cell wall of segments which extended more, than in thosewhich extended less. In this case, 0.2 M mannitol solution wasmost effective, since it inhibited IAA-induced elongation duringpre-incubation and the segments thus incubated extended themost afterward. 5. Extensibility, mm/gr, seemed to parallel the elongation whichhad occurred during pre-incubation, indicating that this value,contrary to To, represented at least partly the result of elongation. From these results we concluded that the growth rate to followis regulated by the minimum stress relaxation time, To, andpossibly by the relaxation rate, b, of the cell wall beforeextension, and these parameters may represent certain biochemicalmodifications of the cell wall components needed for cell extension. (Received August 12, 1974; ) 相似文献
86.
Ayaka Shinkawa Katsuro Yaoi Tomoyuki Kadotani Morikazu Imamura Nobuo Koizumi Hidenori Iwahana Ryoichi Sato 《Current microbiology》1999,39(1):14-20
We investigated the binding proteins for three Cry toxins, Cry1Aa, Cry1Ac, and the phylogenetically distant Cry9Da, in the
midgut cell membrane of the silkworm. In a ligand blot experiment, Cry1Ac and Cry9Da bound to the same 120-kDa aminopeptidase
N (APN) as Cry1Aa. A competition experiment with the ligand blot indicated that the three toxins share the same binding site
on several proteins. The values of the dissociation constants of the three Cry toxins and 120-kDa APN are as low as the case
of other Cry toxins and receptors. These results suggest that distantly related Cry toxins bind to the same site on the same
proteins, especially with APN. We propose that the conserved structure in these three toxins includes the receptor-binding
site.
Received: 12 January 1998 / Accepted: 17 February 1999 相似文献
87.
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89.
Hiroyuki Watanabe Masahiro Ono Ryoichi Ikeoka Mamoru Haratake Hideo Saji Morio Nakayama 《Bioorganic & medicinal chemistry》2009,17(17):6402-6406
This paper describes the synthesis and biological evaluation of a new series of 2,5-diphenyl-1,3,4-oxadiazole (1,3,4-DPOD) derivatives for detecting β-amyloid plaques in Alzheimer’s brains. The affinity for β-amyloid plaques was assessed by an in vitro binding assay using pre-formed synthetic Aβ42 aggregates. The new series of 1,3,4-DPOD derivatives showed affinity for Aβ42 aggregates with Ki values ranging from 20 to 349 nM. The 1,3,4-DPOD derivatives clearly stained β-amyloid plaques in an animal model of Alzheimer’s disease, reflecting the affinity for Aβ42 aggregates in vitro. Compared to 3,5-diphenyl-1,2,4-oxadiazole (1,2,4-DPOD) derivatives, they displayed good penetration of and fast washout from the brain in biodistribution experiments using normal mice. The novel radioiodinated 1,3,4-DPOD derivatives may be useful probes for detecting β-amyloid plaques in the Alzheimer’s brain. 相似文献
90.