Trialkyltrioxanes in flower wax of some decorative roses

The polymeric form in which long-chain aliphatic aldehydes are present in rose flower waxes has been established as the 2,4,6-trialkyl 1,3,5-trioxane.     

特种资源植物好好芭潜在药用价值研究进展

好好芭是近年来国际上新兴的特种油料作物。好好芭种子中富含品质优良的好好芭液体蜡（JLW）,其分子结构独特,用途广泛,具有极高的经济价值和药用价值。希蒙得木素（Simmondsin）是存在于好好芭中的一种多糖类物质,目前普遍认为它对动物的食物摄入量有明显的抑制作用。本文介绍了好好芭液体蜡抗炎作用及希蒙得木素摄食量抑制作用的研究进展,分析指出了研究中存在的问题,并对科研及市场前景进行了展望。     

Physiological functions of pyruvate:NADP+ oxidoreductase and 2-oxoglutarate decarboxylase in Euglena gracilis under aerobic and anaerobic conditions

In Euglena gracilis, pyruvate:NADP⁺ oxidoreductase, in addition to the pyruvate dehydrogenase complex, functions for the oxidative decarboxylation of pyruvate in the mitochondria. Furthermore, the 2-oxoglutarate dehydrogenase complex is absent, and instead 2-oxoglutarate decarboxylase is found in the mitochondria. To elucidate the central carbon and energy metabolisms in Euglena under aerobic and anaerobic conditions, physiological significances of these enzymes involved in 2-oxoacid metabolism were examined by gene silencing experiments. The pyruvate dehydrogenase complex was indispensable for aerobic cell growth in a glucose medium, although its activity was less than 1% of that of pyruvate:NADP⁺ oxidoreductase. In contrast, pyruvate:NADP⁺ oxidoreductase was only involved in the anaerobic energy metabolism (wax ester fermentation). Aerobic cell growth was almost completely suppressed when the 2-oxoglutarate decarboxylase gene was silenced, suggesting that the tricarboxylic acid cycle is modified in Euglena and 2-oxoglutarate decarboxylase takes the place of the 2-oxoglutarate dehydrogenase complex in the aerobic respiratory metabolism.     

Effect of leaf age on epicuticular wax alkanes in Rhododendron

Alkane distribution pattern in epicuticular wax of Rhododendron fortunei cv Admiral Piet Hein leaves remains unchanged from the age of 6 weeks to abscission.     

Steryl acetates in Rhododendron waxes

Sitosteryl acetate was found to be a component of the leaf wakes of seven Rhododendron species. One species, R. augustinii, also contained stig     

The fruit cuticles of wild tomato species exhibit architectural and chemical diversity, providing a new model for studying the evolution of cuticle function

The cuticle covers the aerial epidermis of land plants and plays a primary role in water regulation and protection from external stresses. Remarkable species diversity in the structure and composition of its components, cutin and wax, have been catalogued, but few functional or genetic correlations have emerged. Tomato (Solanum lycopersicum) is part of a complex of closely related wild species endemic to the northern Andes and the Galapagos Islands (Solanum Sect. Lycopersicon). Although sharing an ancestor <7 million years ago, these species are found in diverse environments and are subject to unique selective pressures. Furthermore, they are genetically tractable, since they can be crossed with S. lycopersicum, which has a sequenced genome. With the aim of evaluating the relationships between evolution, structure and function of the cuticle, we characterized the morphological and chemical diversity of fruit cuticles of seven species from Solanum Sect. Lycopersicon. Striking differences in cuticular architecture and quantities of cutin and waxes were observed, with the wax coverage of wild species exceeding that of S. lycopersicum by up to seven fold. Wax composition varied in the occurrence of wax esters and triterpenoid isomers. Using a Solanum habrochaites introgression line population, we mapped triterpenoid differences to a genomic region that includes two S. lycopersicum triterpene synthases. Based on known metabolic pathways for acyl wax compounds, hypotheses are discussed to explain the appearance of wax esters with atypical chain lengths. These results establish a model system for understanding the ecological and evolutionary functional genomics of plant cuticles.     

Effect of pre-processing methods on bond strength between acrylic resin teeth and acrylic denture base resin

doi: 10.1111/j.1741‐2358.2011.00480.x
Effect of pre‐processing methods on bond strength between acrylic resin teeth and acrylic denture base resin Objectives: This study evaluated the effects of various pre‐processing methods on the bond strength between resin and denture teeth. Backgrounds: Debonding of acrylic resin teeth from denture base material is a problem for patients wearing complete dentures. Materials and Methods: Four experimental groups (n = 30) were investigated by subjecting tooth–resin bonding to tensile loading. Specimens were prepared and tested according to the methods of the International Standards Organization (ISO 22112:2005) using a special assembly. Four pre‐processing surface treatments of teeth were applied: (i) ST₁, no treatment applied (control); (ii) ST₂, wax solvent (Dewaks, Faber Kimya & Ilaç, Turkey); (iii) ST₃, boiling water followed by conditioning with methyl methacrylate (MMA) monomer (Meliodent, Bayer Dental, Germany); (iv) ST₄, boiling water followed by wax solvent agent and finally MMA monomer application. Bond strength test was performed using a universal testing machine. Results: All the strength values of the test groups were within clinically acceptable limits. The lowest values were from the ST₁ group and the highest values were in the ST₄ group. Conclusions: Wax elimination methods affected bonding strength. Application of wax solvent and MMA monomer to the ridge lap surfaces of the teeth gave the best results. In clinical practice, this application procedure may decrease the bonding failure of denture teeth.     

Complex biopolymeric systems at stalk/epicuticular wax plant interfaces: A near infrared spectroscopy study of the sugarcane example

Naturally occurring macromolecules present at the epicuticular wax/stalk tissue interface of sugarcane were investigated using near infrared spectroscopy (NIRS). Investigations of water, cellulose, and wax‐cellulose interrelationships were possible using NIRS methods, where in the past many different techniques have been required. The sugarcane complex interface was used as an example of typical phenomena found at plant leaf/stalk interfaces. This detailed study showed that sugarcane cultivars exhibit spectral differences in the CH_n, water OH, and cellulose OH regions, reflecting the presence of epicuticular wax, epidermis, and ground tissue. Spectrally complex water bands (5276 cm^?1 and 7500–6000 cm^?1) were investigated via freeze‐drying experiments which revealed sequentially a complex band substructure (7500–6000 cm^?1), a developing weak H‐bonding system (～7301 cm^?1), and strong H‐bonding (～7062 cm^?1) assigned to water—cellulose interactions. Principal component analysis techniques clarified complex band trends that developed during the desorption experiment. Bands from wax‐free stalk were minimized in the 4327–4080 cm^?1 region (C? H_n vibrational modes associated with long chain fatty compounds), while bands from the stalk tissue (particularly lignin and moisture) became more pronounced. This work is a comprehensive guide to similar studies by scientists involved in a variety of plant and fiber research fields. © 2009 Wiley Periodicals, Inc. Biopolymers 91: 642–651, 2009. This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com     

The Effect of Tripalmitin Crystallization on the Thermomechanical Properties of Candelilla Wax Organogels

The effect of tripalmitin (TP) crystallization on the thermomechanical properties of organogels developed with candelilla wax (CW) was investigated using safflower oil high in triolein (HOSFO) as the liquid phase. Factorial combinations of CW (i.e., 0–3%) and TP (i.e., 0–1%) in the HOSFO were used to develop organogels at three different temperatures (T _set). The onset of crystallization (T _g) during the cooling stage (10 °C/min), the melting temperature (T _M), and the corresponding heat of melting (ΔH _M) of the organogels were determined by differential scanning calorimetry. Results showed that, without CW, the crystallization of TP in the HOSFO at the concentrations and T _set investigated (i.e., −10 °C to 25 °C) did not develop a three-dimensional network that provided significant viscoelasticity (i.e., solid-like behavior) to the HOSFO. The CW developed organogels in the HOSFO with T _M’s that increased from ≈30.5 °C up to ≈42.5 °C as a function of CW concentration. In contrast, in the CW–1% TP system, the co-crystallization of TP and CW resulted in organogels with T_M’s that varied just between 36 °C and 38 °C, independent of the CW concentration. Higher elastic modulus (G′) and yield stress (σ*) were obtained with 3% CW–1.0% TP organogels than with organogels developed just by CW, particularly at T _set’s of −5 °C and 15 °C. This research showed that co-crystallization of TP and CW, occurring at different extent as a function of T _set, resulted in organogels with thermomechanical properties different from the ones showed by CW organogels. The results showed that co-crystallization of triacylglycerides with CW might be a useful alternative to tailor particular physicochemical properties associated to a specific functionality (i.e., melting profile and texture). Organogelation of vegetable oil might be used to develop trans-free vegetable-oil-based spreads and coatings and also novel food products with new textural perceptions for the consumers.