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Two new triterpene synthase cDNAs, named as OEW and TRW, were cloned from olive leaves (Olea europaea) and from dandelion roots (Taraxacum officinale), respectively, by the PCR method with primers designed from the conserved sequences found in the known oxidosqualene cyclases. Their ORFs consisted of 2274 bp nucleotides and coded for 758 amino acid long polypeptides. They shared high sequence identity (78%) to each other, while they showed only about 60% identities to the known triterpene synthases LUPI (lupeol synthase clone from Arabidopsis thaliana) and PNY (b-amyrin synthase clone from Panax ginseng) at amino acid level. To determine the enzyme functions of the translates, they were expressed in an ERG7 deficient yeast mutant. Accumulation of lupeol in the cells of yeast transformants proved both of these clones code for lupeol synthase proteins. An EST (expression sequence tag) clone isolated from Medicago truncatula roots as a homologue of cycloartenol synthase gene, exhibits high sequence identity (75±77%) to these two lupeol synthase cDNAs, suggesting it to be another lupeol synthase clone. Comparatively low identity (< 57%) of LUP1 from Arabidopsis thaliana to either one of these clones leaves LUP1 as a distinct clone among lupeol synthases. From these sequence comparisons, now we propose that two branches of lupeol synthase gene have been generated in higher plants during the course of evolution.Keywords: lupeol synthase; Olea europaea; Taraxacum officinale; triterpene synthase; molecular evolution.In mammals, plants, fungi and yeasts, sterols serve as essential membrane constituents, growth regulating substances and precursors of various hormones [1,2]. In the plant kingdom, besides sterols, a large number of nonsteroidal triterpene derivatives exist that are recognized as secondary metabolites due to their apparent lack of physiological functions in the producing plants [3]. They are produced species specifically, and thus could be considered as a chemical expression of plant species. It is reasonable to assume the ability of sterol biosynthesis to be inherent to all plants and highly conserved from the progenitors, while the ability to produce characteristic triterpenoids by individual plant species to be acquired in the process of plant evolution.Biosynthetic pathways leading to sterols and triterpenes are completely identical to each other up to the formation of 2,3-oxidosqualene and branch at its cyclization step [4]. As structural diversity of triterpene is primarily generated at this cyclization step catalyzed by triterpene synthases, it can be said that diversity of these synthases reflects diversity of plant species (Fig. 1). Up to now, cDNA cloning of four cycloartenol synthases (from Arabidopsis thaliana (CAS1) [5], Pisum sativum [6], Panax ginseng [7] and Allium macrostemon [8]), three triterpene synthases two b-amyrin synthases (PNY and PNY2) from P. ginseng [7,9], and a lupeol synthase (LUP1) from A. thaliana [10] and another oxidosqualene cyclase (OSC) of unknown function from P. ginsen...

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The new chiral ligands (R)-/(S)-N-((1-phenylethyl)carbamothioyl)benzamide (L1/L2), (R)-/(S)-N-((1-phenylethyl)carbamothioyl)thiophene-2-carboxamide (L3/L4), and (R)-/(S)-N-((1-phenylethyl)carbamothioyl)furan-2-carboxamide (L5/L6) were synthesized, characterized, and used to prepare novel chiral Ru(II) complexes. The chiral Ru(II) complexes 1–6 were obtained from reactions between the chiral ligands L1–L6 and [RuCl2(p-cymene)2]2. The complexes were characterized by analytical and spectroscopic (NMR, FT-IR, electronic) techniques. The solid-state structures of the ligands L1 and L3 and complexes 1, 4, and 6 were determined by single-crystal X-ray diffraction methods. In all of the complexes, the ligand is bound to the Ru(II) center only via the sulfur donor atom. This monodentate coordination of the acylthiourea ligands was observed for the first time with ruthenium. The Ru(II) complexes 1–6 all act as efficient catalysts for the asymmetric transfer hydrogenation of aromatic ketones in the presence of 2-propanol and KOH to produce chiral alcohols. All of the catalysts showed excellent conversions of up to 99% and enantiomeric excesses of up to 99%.

Magnesium phthalocyanine (MgPc) is a blue pigment whose X-phase is known to exhibit an intense near-IR-absorption. Because of this, MgPc has attracted attention as a material useful for laser printers as well as optical disks based on GaAsAl laser diodes. The near-IR absorption has, therefore, been investigated from the standpoints of exciton coupling effects on the basis of the crystal structure. Two kinds of six-coordinate MgPc complexes were grown from solution and their structures were analyzed:  MgPc/(H2O)2·(N-methyl-2-pyrrolidone)2 (crystal 1) and MgPc/(2-methoxyethanol)2 (crystal 2). In both crystals, two oxygen atoms of the solvent molecule are coordinated to the central Mg atom above and below the molecular plane, forming a distorted sp3d2 octahedron. Of these crystals, only crystal 1 exhibits a near-IR absorption whose spectral shape is quite similar to that of the X-phase. In addition, the X-phase is also found to contain two water molecules in the normal ambient atmosphere. The near-IR absorption in both crystal 1 and the X-phase can reasonably be interpreted as arising from exciton coupling effects based on the molecular arrangement of MgPc/(H2O)2.

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The freezing/melting behavior of water confined in mesopores was evaluated by differential scanning calorimetry (DSC) using micropore-free SBA-15 materials with different pore sizes as model materials. We determined the mesoporous structure (pore size distribution, specific surface area, and pore volume) by using Ar gas adsorption/desorption measurements, and investigated the thickness dependence of nonfreezable pore water (t nf ) on pore size. The t nf value was calculated as the difference between the pore radius, calculated from an Ar adsorption isotherm using the nonlocal density functional theory (NLDFT) analysis, and the radius of ice crystals that formed in the mesopores during the DSC measurement. Several studies have reported t nf values ranging from 0.35 to 1.05 nm depending on the evaluation method, whereas the t nf value estimated for the SBA-15 used in this work was approximately 0.7 nm. The difference between the reported t nf values and the value obtained in this work is mainly due to an underestimation of the pore diameter by the method based on the classical Kelvin equation. After appropriate correction of the pore diameter, the reported t nf value agreed with our results.