Study of enzyme inhibitory activities by dipyridamole

Inhibitory activities of Dipyridamole (DPM, 2,6-bis(diethanolamino)-4,8-dipiperidinopyrimido(5,4-d)py rim idine) against xanthine oxidase (XO), carbonic anhydorase (CA) and monoamine oxidase (MAO) were studied, in vitro. DPM did not inhibit XO and CA, but it strongly inhibited MAO. The type of inhibition by DPM against MAO with respect to benzylamine as a substrate was uncompetitive.     

QUATERNARY STRUCTURE OF PEA PHYTOCHROME I DIMER STUDIED WITH SMALL-ANGLE X-RAY SCATTERING and ROTARY-SHADOWING ELECTRON MICROSCOPY

Abstract— The quaternary structure of pea phytochrome type I (PI) dimer in the red-light-absorbing form was studied by small-angle X-ray scattering (SAXS) technique and rotary-shadowing electron microscopy. Structural parameters for PI 114 kDa chromopeptide dimer and its tryptically digested N-terminal 59 kDa chromopeptide monomer, such as average electron density, molecular volume and the second moment of electron density distribution, were determined in terms of SAXS using the contrast variation method. Furthermore, by means of model simulation for the scattering profiles of the chromopeptides, most plausible structural models for both peptides were constructed. The distance between the chromophoric domains was estimated to be about 70 A in the resultant model for 114 kDa chromopeptide dimer. Furthermore, the model was consistent with the electron-micrographic images of both the intact PI dimer and the PI 114 kDa chromopeptide dimer, so that the N-terminal 7 kDa fragment did not significantly contribute the low-resolution images of the dimer.     

Discotic Liquid Crystals of Transition Metal Complexes, 19: Discotic Mesomorphism and Double Clearing Behavior of Octakis(dialkoxyphenyl)phthalocyanine Derivatives

Eight novel octakis(3,4-dialkoxyphenyl)- phthalocyanine derivatives, Cn-M (2, M=2H; 3, M=Ni; 4, M=Cu; a, decyloxy; b, undecyloxy; c, dodecyloxy), have been synthesized and characterized. It was found that each of the derivatives exhibits discotic liquid crystalline properties, and that each of the Cn–Cu (4) derivatives has two kinds of D_rd2( P 2₁/ a ) mesophases. These Cn–Cu (4a,b,c) and C₁₂–2H (2c) derivatives exhibit a unique double clearing behavior.     

Photoresponsive porphyrin-imprinted polymers prepared using a novel functional monomer having diaminopyridine and azobenzene moieties

A novel photoresponsive functional monomer bearing diaminopyridine and azobenzene moieties was synthesized and applied to the preparation of photo-regulated molecularly imprinted polymers, which can recognize porphyrin derivatives through hydrogen bonding. The binding affinity of the imprinted cavities was regulated by UV irradiation, suggesting that azobenzene groups located inside the binding sites worked as photosensitizers and the trans-cis isomerization could regulate the affinity for the target compounds. Repetitive binding of the target compound to trans-IP and cis-IP was directly monitored by slab optical waveguide spectroscopy and the photo-mediated regulation of binding affinity was successfully confirmed.     

Solution properties of perfluorinated anionic surfactants with divalent counterion of separate electric charges

Novel surfactants of perfluorinated double long-chain salts with divalent counterion of separate electric charge, 1,1-(1,omega-alkanediyl)bispyridinium diperfluorononanoate (CnBP(FC9)2, n = 2, 4, 6, 8) were newly synthesized. Their solution properties were investigated by surface tension measurement over the temperature range from 298.2 to 313.2 K, where magnesium diperfluorononanoate (Mg(FC9)2) was employed as a reference surfactant with divalent counterion of concentrated electric charge. From change of surface tension with concentration, the critical micelle concentration (CMC), surface excess (Gamma), apparent molecular surface area (A), and -log(concentration to reduce surface tension of water by 20 mN m-1) (pC20) were determined. The CMC values of CnBP(FC9)2 decreased with increasing charge separation and with increasing temperature, where the values of CnBP(FC9)2 were much smaller than those of Mg(FC9)2. In addition, the pC20 values of the former were also much larger than those of the latter. These results indicate a strong influence of the extent of charge separation or the spacer length of the counterions upon surface activity of the fluorinated surfactants. The surface excess or the corresponding apparent molecular surface area monotonously changed with the spacer length (n < or = 6), whereas the behavior for n = 8 was much different from the other CnBP(FC9)2 due to conformational change in the in-between alkanediyl chain. The entropy changes (Deltas) for the surface adsorption or condensation were found to be mostly negative for CnBP(FC9)2, where the changes approached zero with an increase in the charge separation. On the other hand, the changes for Mg(FC9)2 were positive over the whole concentration below the CMC. In addition, Brewster angle microscopy indicated no condensation of the present surfactants just at the air/solution interface.     

Nucleophilic aromatic substitution using Et3SiH/cat. t-Bu-P4 as a system for nucleophile activation

A novel type of deprotonative arylation of nucleophiles was conducted using Et(3)SiH/cat. t-Bu-P4 and the powerful S(N)Ar reactions of aryl fluorides were accomplished using alcohols and malonates as nucleophiles.     

Preferred conformations of some 2-pyridyl substituted thiourea derivatives. A reinvestigation of NMR spectral data

A previous report involving ¹H nmr spectra of some 1-phenyl and 1-benzoyl 3-(2-pyridyl)thioureas was reinvestigated and found to be incorrect. Analysis of the data permits the designation of preferred conformations for these systems.     

A survey of metabolic changes in potato leaves by NMR‐based metabolic profiling in relation to resistance to late blight disease under field conditions

Non‐targeted nuclear magnetic resonance (NMR)‐based metabolic profiling was applied to potato leaves to survey metabolic changes associated with late blight resistance under field conditions. Potato plants were grown in an experimental field, and the compound leaves with no visible symptoms were collected from 20 cultivars/lines at two sampling time points: (i) the time of initial presentation of symptoms in susceptible cultivars and (ii) 12 days before this initiation. ¹H NMR spectra of the foliar metabolites soluble in deuterium oxide‐ or methanol‐d₄‐based buffers were measured and used for multivariate analysis. Principal component analysis for six cultivars at symptom initiation showed a class separation corresponding to their levels of late blight resistance. This separation was primarily explained by higher levels of malic acid, methanol, and rutin and a lower level of sucrose in the resistant cultivars than in the susceptible ones. Partial least squares regression revealed that the levels of these metabolites were strongly associated with the disease severity measured in this study under field conditions. These associations were observed only for the leaves harvested at the symptom initiation stage, but not for those collected 12 days beforehand. Subsequently, a simple, alternative enzymatic assay for l ‐malic acid was used to estimate late blight resistance, as a model for applying the potential metabolic marker obtained. This study demonstrated the potential of metabolomics for field‐grown plants in combination with targeted methods for quantifying marker levels, moving towards marker‐assisted screening of new cultivars with durable late blight resistance. Copyright © 2016 John Wiley & Sons, Ltd.