Leaf Surface Wax Chemicals in Trichosanthes anguina (Cucurbitaceae) Cultivars Mediating Short-Range Attraction and Oviposition in Diaphania indica.

Larval Diaphania indica (Saunders) (Lepidoptera: Crambidae) cause complete defoliation of Trichosanthes anguina L. and reduce crop yield in India. Females lay eggs on the leaf surface, and therefore leaf surface waxes are potentially involved in host selection. Alkanes and free fatty acids are the major constituents of leaf surface waxes, so a study was conducted to determine whether these wax constituents from three T. anguina cultivars (MNSR-1, Baruipur Long, and Polo No.1) could act as short-range attractants and oviposition stimulants in D. indica females. Twenty n-alkanes from n-C14 to n-C36 and 13 free fatty acids from C12:0 to C21:0 were detected in the leaf surface waxes of these cultivars. Heptadecane and stearic acid were predominant among n-alkanes and free fatty acids, respectively, in these cultivars. Females showed attraction towards one leaf equivalent surface wax of each of these cultivars against solvent controls (petroleum ether) in Y-tube olfactometer bioassays. A synthetic blend of heptadecane, eicosane, hexacosane, and stearic acid, a synthetic blend of hexacosane and stearic acid, and a synthetic blend of pentadecane and stearic acid comparable to amounts present in one leaf equivalent surface wax of MNSR-1, Baruipur Long, and Polo No.1, respectively, were short-range attractants and oviposition stimulants in D. indica. Female egg laying responses were similar to each of these blends, providing information that could be used to developing baited traps in integrated pest management (IPM) programs.

Preparation and characterization of oleogel emulsions: A comparative study between the use of recovered and commercial sunflower waxes as structuring agent.

The objective of this study was to evaluate the capacity of recovered sunflower waxes (RW) to be used as a structuring agent of oleogel emulsions in comparison with commercial sunflower waxes (CW). RW were recovered from filter cake with a simple hexane extraction procedure. For this purpose, oleogel-based emulsions were prepared using 2%, 3.5%, and 5% w/w wax in oleogel and characterized using several physicochemical techniques in order to evaluate the potential of these materials to develop products with functionality similar to commercial margarines. The total wax esters content of RW was similar to that of the CW and was mainly composed of wax esters with more than 44 carbon atoms (crystallizable waxes). Polarized light and scanning electron microscopy showed that RW produced emulsions with more intricate crystalline networks composed of smaller platelets than CW. The melting enthalpy was greater in CW emulsions than RW emulsions, which was in agreement with the thermal behavior found for CW and RW. The oil binding capacity of CW oleogel emulsions was higher than the RW ones, and this property improved with the increase in wax concentration. Likewise, the elastic behavior, as well as hardness and adhesiveness, increased with the wax content as a result of a greater amount of microstructural elements composing the network of these semisolid materials. The oleogel emulsions stability was monitored for 2 months at room temperature. The increase of CW concentration slowed down the coalescence process, but this behavior was not observed for RW emulsions. Obtained results demonstrated that RW oleogel emulsions have the potential to replace the functionality of soft spreadable products. PRACTICAL APPLICATION: Wax esters are organogelators that have been shown to successfully gel liquid oil at low concentrations. In this work, we are interested in evaluating the potential of sunflower waxes recovered from filter cake, a waste generated during refined oil production, to structure oil and produce oil-in-water emulsions with functionality similar to commercial margarines. With this, it is sought not only the development of healthier fats but also the use of wastes to generate more sustainable products.

Sunflower wax recovered from oil tank settlings: Revaluation of a waste product from the oilseed industry.

BACKGROUND: The sunflower oil industry produces a large amount of waste that is not currently commercially exploited, as in the case of oil-tank settlings. The recovery of a high value-added by-product, such as sunflower wax, would increase the commercial value of this waste. In this original research paper, a method that allows the recovery and purification of this by-product was developed. The wax was characterized and its potential use as an organogelator agent was investigated. RESULTS: The waste sample was composed of 45.1% oily material, 16.9% of this being impure waxes. Purification was performed through two different methods, obtaining three waxes with different degrees of purity. All the waxes were composed of wax esters with a range of 40-60 carbon atoms, exhibiting traces of carotenes, free fatty acids, and free fatty alcohols. The presence of phospholipids was observed in two of them. The third wax presented a higher total wax ester content and physicochemical characteristics (color and thermal behavior) similar to those of commercial sunflower waxes, and was the most efficient organogelator agent, requiring only a small amount of wax (1.5%) to structure high oleic sunflower oil. CONCLUSION: It was verified that sunflower wax could be recovered from oil-tank settlings. A purification method that allowed sunflower wax with similar physicochemical properties to those of commercial waxes to be obtained was also developed. The purified waxes were capable of structuring high oleic sunflower oil. © 2019 Society of Chemical Industry.

Sorbent-excluding sample preparation method for GC-MS pesticide analysis in apple peel.

Apple peel is frequently exposed to pesticides, especially in the last stages of the pesticide treatment practice. For a certain period, peel retains most of the applied pesticides, which precisely indicates the presence of pesticide residues. This study was conducted to establish and evaluate the method for the residue analysis of pyrimethanil, cyprodinil, trifloxystrobin, bifenthrin and boscalid by GC-MS in peel of Granny Smith, Golden Delicious and Idared varieties. The method consisted of few steps, without the routine usage of sorbents, and resulted in efficient removal of waxes, targeted as main interferences in GC-MS analysis. The matrix effect, boscalid selectivity issue, trend of lower trueness for bifenthrin in all matrices and for all analytes in Granny Smith matrix were in some way associated with the waxes. Finally, the method was applied to the analysis of three varieties of apple orchard samples, after 9 and 5 months of treatment with commercial formulations that contain pyrimethanil, cyprodinil and boscalid as active ingredients. Since the developed method consisted of few steps and used nontoxic and economic reagents, it could be implemented as a fast, economic and reliable screening method.

Water Extracts of Hull-less Waxy Barley (Hordeum vulgare L.) Cultivar 'Boseokchal' Inhibit RANKL-induced Osteoclastogenesis.

Osteoporosis is a disease that leads to reduced bone mineral density. The increase in patient and medical costs because of global aging is recognized as a problem. Decreased bone mass is a common symptom of bone diseases such as Paget's disease, rheumatoid arthritis, and multiple myeloma. Osteoclasts, which directly affect bone mass, show a marked increase in differentiation and activation in the aforementioned diseases. Moreover, these multinucleated cells made from monocytes/macrophages under the influence of RANKL and M-CSF, are the only cells capable of resorbing bones. In this study, we found that the water extracts of Boseokchal (BSC-W) inhibited osteoclast differentiation in vitro and investigated its inhibitory mechanism. BSC-W was obtained by extracting flour of Boseokchal using hexane and water. To osteoclast differentiation, bone marrow-derived macrophage cells (BMMs) were cultured with the vehicle (0.1% DMSO) or BSC-W in the presence of M-CSF and RANKL for 4 days. Cytotoxicity was measured by CCK-8. Gene expression of cells was confirmed by real-time PCR. Protein expression of cells was observed by western blot assay. Bone resorption activity of osteoclast evaluated by bone pit formation assay using an Osteo Assay Plate. BSC-W inhibited RANKL-induced osteoclastogenesis in a dose-dependent manner without exerting a cytotoxic effect on BMMs. BSC-W decreased the transcriptional and translational expression of c-Fos and NFATc1, which are regulators of osteoclastogenesis and reduced the mRNA expression level of TRAP, DC-STAMP, and cathepsin K, which are osteoclast differentiation marker. Furthermore, BSC-W reduced the resorption activity of osteoclasts. Taken together, our results indicate that BSC-W is a useful candidate for health functional foods or therapeutic agents that can help treat bone diseases such as osteoporosis.

Compositional and morphological analyses of wax in northern wild berry species.

Aerial surfaces of plants are covered by a waxy cuticle protecting plants from excessive water loss and UV light. In the present study, composition and morphology of cuticular waxes of northern wild berry species bilberry (Vaccinium myrtillus L.), lingonberry (V. vitis-idaea L.), bog bilberry (V. uliginosum L.) and crowberry (Empetrum nigrum L.) were investigated. Scanning electron microscopy (SEM) revealed differences in epicuticular wax morphology, and gas chromatography-mass spectrometry (GC-MS) analysis confirmed variation in chemical composition of cuticular waxes between the berry species. The dominant compounds in bilberry and lingonberry cuticular waxes were triterpenoids, while fatty acids and alkanes were the dominant ones in bog bilberry and crowberry, respectively. Wax extracted by supercritical fluid extraction (SFE) from industrial press cakes of bilberry and lingonberry contained linoleic acid and γ-linolenic acid as the dominant compounds. Furthermore, in vitro sun protection factor (SPF) of berry waxes depicted good UV-B absorbing capacities.

Preliminary study on analysis and removal of wax from a Carrara marble statue.

This preliminary study has mainly focused on the wax identification by nuclear magnetic resonance (NMR) and removal. Wax is used for many purposes in the field of art as protective coatings on wooden, stone or metal objects. From the comparison of the spectra H NMR and in particular with the correspondence of the resonance peaks of the samples taken from the statue and beeswax and paraffin, we can conclude that the wax applied on the statue surface is beeswax. From our data, it can be concluded that, to remove the beeswax, from any stone support, the more effective solvent is the mixture of cyclohexane/ethyl acetate. The removal percentages ranged from 19 to 99%. Lower percentages of removal have been observed in the case of yellow marble, probably because of its high porosity. We can affirm that, this solvent mixture can be employed in real art objects using cotton swabs to remove protective wax.

Analysis of Cuticular Lipids of the Pharaoh Ant (Monomorium pharaonis) and Their Selective Adsorption on Insecticidal Zeolite Powders.

The pharaoh ant is a notorious and hard to eradicate pest, which poses a threat in hospitals, spreading pathogens and contaminating sterile equipment. When applied on ants, zeolites adsorb part of their epicuticular wax layer. The ants are then vulnerable to desiccation, since this layer regulates water exchange. We analyzed the chemical composition of this wax layer using GC-MS (Gas Chromatography-Mass Spectrometry). A hexane wash of M. pharaonis foragers resulted in the identification of 53 components, four of which were not previously defined in Monomorium species. Selective adsorption of specific compounds on zeolites assisted in the identification of compounds which could not be separated on the GC column and allowed for the identification of three additional compounds. Zeolites show different affinities for the wax compounds depending on pore structure and chemical composition. Selective adsorption of alkanes on zeolites is also investigated in the fields of refinery processes and catalysis. Pore mouth and key lock adsorption mechanisms and selectivity according to molecular weight and branching, investigated in these fields, are also involved in adsorption processes of epicuticular waxes. The insecticidal activity of a zeolite is related to adsorption selectivity rather than capacity. One of the best adsorbing zeolites showed limited insecticidal activity and can be considered as a non-lethal alternative for epicuticular wax sampling.

Structure and rheology of oleogels made from rice bran wax and rice bran oil.

Structural and rheological properties of oleogels consisting of 0.5-25 wt% rice bran wax (RBX) in rice bran oil (RBO) were explored. RBX was an efficient, thermoreversible oleogelator capable of structuring RBO at concentrations as low as 0.5 wt% RBX. A qualitative temperature-composition phase diagram showed that oleogels containing higher concentrations of RBX were expectedly the most resistant to melting. In oleogels at higher RBX concentrations, polarized light microscopy revealed the presence of a network of interlinked, long aspect ratio wax crystal needles up to 50 µm long. Upon heating, RBX crystals did not undergo any structural transition, based on the constant short spacings at ~ 4.16 and ~ 3.73 Å, indicative of an orthorhombic subcell, and d001 long spacing at 74-76 Šthat persisted until RBX fusion. This long spacing was ascribed to the presence of wax esters consisting of long-chain saturated fatty acids (C24 and C22) esterified to C28 - C34 saturated fatty alcohols. During cooling from 90 to 20 °C, the increase in oleogel viscosity resulting from the RBX liquid-solid phase transition was corroborated by DSC-based crystallization onset and enthalpy data. Similarly, elastic moduli and hardness both rose with increasing RBX concentration. This study, which demonstrated that RBX can structure RBO with distinct concentration-dependent properties, serves as the foundation for the development of oleogel-based approaches to saturated and trans fats replacement in processed foods.

Solvent-Extracted Wool Wax: Thermotropic Properties and Skin Efficacy.

BACKGROUND/AIMS: Wool wax is a soft, yellow, waxy substance that is secreted by the sebaceous glands of sheep. The purpose of wool wax is to waterproof and protect the wool. Chemically, wool wax is a complex mixture of esters, fatty acids, and alcohols. Wool waxes with different prop-erties can be obtained by following different extraction methodologies. METHODS: Two differently extracted wool waxes are compared in this study. Their effectiveness in mimicking the properties of skin lipids is evaluated. In addition, the lipid compositions and thermotropic behaviours of the 2 differently extracted wool waxes were evaluated. RESULTS: The solvent-extracted wool wax was found to have a significantly higher polar lipid content than that of the water-extracted wool wax. This increase in the polar character of the solvent-extracted wool wax was also demonstrated by increased values of transition and degradation temperatures in the differential scanning calorimetry and thermogravimetric analyses, respectively. In addition, solvent-extracted wool wax demonstrated the ability to reinforce stratum corneum lipids, which led to improved skin barrier function. CONCLUSIONS: The suitability of the solvent-extracted wool wax for application in the preparation of cosmetics and dermatological products was demonstrated.

Emulsions of sunflower wax in pectin aqueous solutions: Physical characterization and stability.

The knowledge of the stability and physical properties of film-forming solutions is necessary for optimizing the process design of films. In order to evaluate their applicability for the production of edible films, the rheological and microstructural properties, particle size and physicochemical stability of aqueous emulsions of low methoxyl pectin and sunflower waxes from normal and high-oleic hybrids were assessed. Emulsions were prepared with different pectin concentrations (1, 2 and 3% w/w) and wax proportions (0.1, 0.2 and 0.3 g/g pectin). The rheological behavior was best described by the power law model. The values of the behavior index (n) were close to 1, exhibiting a behavior close to Newtonian fluids. The addition of waxes caused an increase in viscosity and shear stress. The particle size of the emulsions made with waxes from high-oleic sunflower was smaller than those from the normal hybrid. In most cases, size distributions with greater height and less amplitude were obtained, mainly when the pectin content was higher. Confocal images allowed to observe the presence of waxes and their dispersion in the pectin matrix. Destabilization phenomena such as sedimentation, coalescence and creaming were observed at long test times independent of the wax origin. These results evidence the potential use of these emulsions for the manufacture of edible films.

Variations of Leaf Cuticular Waxes Among C3 and C4 Gramineae Herbs.

Modern C4 plants are commonly distributed in hot and dry environments whereas C3 plants predominate in cool and shade areas. At the outmost of plant surface, the deposition and chemical composition of cuticular waxes vary under different environmental conditions. However, whether such variation of cuticular wax is related to the distribution of C3 and C4 under different environmental conditions is still not clear. In this study, leaves of six C3 Gramineae herbs distributed in spring, Roegneria kamoji, Polypogon fugax, Poa annua, Avena fatua, Alopecurus aequalis, and Oplismenus undulatifolius, and four C4 and one C3 Gramineae herbs distributed in summer, Digitaria sanguinalis, Eleusine indica, Setaria viridis, S. plicata, and O. undulatifolius, were sampled and analyzed for cuticular wax. Plates were the main epicuticular wax morphology in both C3 and C4 plants except S. plicata. The plates melted in C4 plants but not in C3 plants. The total cuticular wax amounts in C4 plants were significantly lower than those in C3 plants, except for O. undulatifolius. Primary alcohols were the most abundant compounds in C3 plants, whereas n-alkanes were relatively the most abundant compounds in C4 plants. C29 was the most abundant n-alkane in C3 plants except for O. undulatifolius, whereas the most abundant n-alkane was C31 or C33 in C4 plants. The average chain length (ACL) of n-alkanes was higher in C4 than in C3 plants, whereas the ACL of n-alkanoic acids was higher in C3 than C4 plants. The cluster analysis based on the distribution of n-alkanes clearly distinguished C3 and C4 plants into two groups, except for O. undulatifolius which was grouped with C4 plants. These results suggest that the variations of cuticular waxes among C3 and C4 Gramineae herbs are related to the distribution of C3 and C4 plants under different environmental conditions.

Antiprotozoal activity of extracts and isolated triterpenoids of 'carnauba' (Copernicia prunifera) wax from Brazil.

CONTEXT: 'Carnauba' wax is a natural product obtained from the processing of the powder exuded from Copernicia prunifera (Miller) H. E. Moore (Arecaceae). This material is widely used in the Brazilian folk medicine, including the treatment of rheumatism and syphilis. OBJECTIVE: To investigate the antiprotozoal activity of hexane and EtOH extracts from the 'carnauba' wax as well as from the isolated compounds from the bioactive extracts. MATERIAL AND METHODS: Two different samples of 'carnauba' (C. prunifera) waxes - types 1 and 4 - were individually extracted using hexane (EH) and EtOH (EE). Aliquots of hexane (type 1 - EH-1 and EH-4) and EtOH (type 4 - EE-1 and EE-4) extracts were tested against promastigote (2-200 µg/mL in DMSO during 48 h at 24 °C) and amastigote (3-150 µg/mL in DMSO during 120 h at 37 °C) forms of Leishmania infantum as well as against trypomastigote (3-150 µg/mL in DMSO during 24 h at 37 °C) forms of Trypanosoma cruzi. Bioactive extracts EH-1 and EE-4 were subjected to a bioactivity-guided fractionation to afford three dammarane-type triterpenoids (1-3). The in vitro antiprotozoal activities of the obtained compounds were evaluated as described above. Additionally, the cytotoxicity activity of compounds 1-3 against mammalian conjunctive cells (NCTC - 2-200 µg/mL in DMSO during 48 h at 37 °C) was determined. RESULTS: From the bioactive hexane and EtOH extracts from the 'carnauba' (C. prunifera) wax, were isolated three dammarane-type triterpenoids: (24R*)-methyldammar-25-ene-3ß,20-diol (carnaubadiol, 1), (24R*)-methyldammara-20,25-dien-3-one (2) and (24R*)-methyldammara-20,25-dien-3α-ol (3). These compounds were identified based on the analysis of NMR and MS spectroscopic data. Compounds 1-3 were effective against the intracellular amastigotes of L. infantum, with IC50 values ranging from 8 to 52 µM, while compounds 1 and 3 displayed activity against trypomastigote forms of T. cruzi with IC50 values of 15 and 35 µM, respectively. The mammalian cytotoxicity assay demonstrated no damage to NCTC conjunctive cells up to 200 µM, except for compound 1, which demonstrated a CC50 value of 34 µM. CONCLUSION: Based on the results, it was possible to conclude that the detected antiprotozoal bioactivity of 'carnauba' (C. prunifera) wax extracts could be related to the presence of the natural dammarane triterpenoid derivatives. The results suggested that these compounds could be used as promising scaffolds for drug design studies for leishmaniasis and Chagas disease.

Insecticidal Properties of a Highly Potent Wax Isolated from Dolichandra cynanchoides Cham.

Bioassay-guided fractionation of an ethanolic extract of the aerial parts of Dolichandra cynanchoides Cham. (Bignoniaceae) led to the isolation of a natural wax with anti-insect activity against Spodoptera frugiperda (Noctuidae) and Epilachna paenulata (Coleptera). The compound was identified spectroscopically as an ester of a C27 fatty acid and a C25 alcohol, pentacosyl heptacosanoate (1). The effective doses of 1 for 50% feeding inhibition (ED50) of S. frugiperda and E. paenulata were 0.82 and 8.53 µg/cm², respectively, in a choice test, while azadirachtin showed ED50 of 0.10 and 0.59 µg/cm², respectively. In a no-choice test, both insects refused to feed on leaves treated with 1 at doses of 0.1 µg/cm² or greater inhibiting larval growth and dramatically reducing survival. The lethal doses 50 (LD50) of 1 were 0.39 and 0.68 µg/cm² for S. frugiperda and E. paenulata, respectively. These results indicate that 1 has potential for development as botanical insecticides. Similar esters might be obtainable in large quantities as many edible crops produce wax esters that are discarded during food processing. Research on these materials could lead to the detection of similar waxes with insecticidal activity.

Clinical safety evaluation of marine oil derived from Calanus finmarchicus.

Marine oils are rich in polyunsaturated fatty acids (PUFAs), including docosahexaenoic and eicosapentaenoic acid. These PUFAs are associated with health benefits and additional sustainable sources of marine oils are desirable. One of the source organisms is Calanus finmarchicus, a copepod endemic to the North Atlantic. PUFAs in the lipid fraction of this organism are largely in the form of wax esters. To assess the safety of these wax esters as a source of PUFAs, a randomized, double-blinded, placebo-controlled clinical trial was conducted whereby 64 subjects consumed 2 g Calanus oil in capsule form daily for a period of one year. A group of 53 subjects consumed placebo capsules. At baseline, 6-, and 12-months, series of evaluations were conducted, including: vital signs, clinical chemistry and hematological evaluations, and adverse event reporting. Food intake and physical exercise were controlled by means of a questionnaire. There were no effects on Calanus oil treatment on any of the safety parameters measured. A slight increase in the incidence of eczema was reported in the Calanus oil group, but the response was minor in nature, not statistically significant after controlling for multiple comparisons, and could not be attributed to treatment.

Advances in industrial prospective of cellulosic macromolecules enriched banana biofibre resources: A review.

Biological macromolecules enriched resources are rapidly emerging as sustainable, cost effective and environmental friendly materials for several industrial applications. Among different biological macromolecules enriched resources, banana fibres are one of the unexplored high potential bio-resources. Compared to various natural fibres such as jute, coir, palm etc., the banana fibres exhibits a better tensile strength i.e. 458 MPa with 17.14 GPa tensile modulus. Traditionally used petroleum based synthetic fibres have been proven to be toxic, non-biodegradable and energy intensive for manufacturing. Cellulosic banana fibres are potential engineering materials having considerable scope to be used as an environmental friendly reinforcing element for manufacturing of polymer based green materials. This paper summarizes the world scenario of current production of biological macromolecules rich banana residues and fibres; major user's of banana fibres. The quality and quantity of biological macromolecules especially the cellulose, hemicellulose, lignin, wax, engineering and mechanical properties of banana biofibre resources are reported and discussed. Subsequently, the findings of the recent research on bio resource composites, materials performance and opportunities have been discussed which would be a real challenge for the tomorrow world to enhance the livelihood environmental friendly advancement.

Effect of processing systems on the quality and stability of Chemlali olive oils.

The present work has been carried out to ascertain the influence of different processing systems employed in olive process on the chemical composition, quality and stability of three Chemlali olive oils. Among these oils, two were classified as extra-virgin olive oils and the third named repassed olive oil was classified as an ordinary virgin olive oil. The analysis of the effect of the processing (two- and three-phases) on the analytical determinations values, revealed statistically significant differences (p<0.05) in some parameters, mainly in oxidative stability, antioxidant activity, total waxes, total phenols, o-diphenols and α-tocopherol contents as well as phenolic composition. The phenolic composition values were higher in the extra-virgin olive oil obtained from the two-phase system than in that obtained from the three-phase processing because it does not require the addition of water to the olive paste. Nevertheless, they were lower in the ordinary virgin olive oil (repassed olive oil) which was obtained by introducing hot water to the wet residues into the centrifugation processing at two-phases, than those in the extra-virgin olive oils obtained from the two- and three-phase processing.

Effect of substrate choice and tissue type on tissue preparation for spectral histopathology by Raman microspectroscopy.

Raman spectroscopy is a non-destructive, non-invasive, rapid and economical technique which has the potential to be an excellent method for the diagnosis of cancer and understanding disease progression through retrospective studies of archived tissue samples. Historically, biobanks are generally comprised of formalin fixed paraffin preserved tissue and as a result these specimens are often used in spectroscopic research. Tissue in this state has to be dewaxed prior to Raman analysis to reduce paraffin contributions in the spectra. However, although the procedures are derived from histopathological clinical practice, the efficacy of the dewaxing procedures that are currently employed is questionable. Ineffective removal of paraffin results in corruption of the spectra and previous experiments have shown that the efficacy can depend on the dewaxing medium and processing time. The aim of this study was to investigate the influence of commonly used spectroscopic substrates (CaF2, Spectrosil quartz and low-E slides) and the influence of different histological tissue types (normal, cancerous and metastatic) on tissue preparation and to assess their use for spectral histopathology. Results show that CaF2 followed by Spectrosil contribute the least to the spectral background. However, both substrates retain paraffin after dewaxing. Low-E substrates, which exhibit the most intense spectral background, do not retain wax and resulting spectra are not affected by paraffin peaks. We also show a disparity in paraffin retention depending upon the histological identity of the tissue with abnormal tissue retaining more paraffin than normal.

The inhibitor of wax 1 locus (Iw1) prevents formation of ß- and OH-ß-diketones in wheat cuticular waxes and maps to a sub-cM interval on chromosome arm 2BS.

Glaucousness is described as the scattering effect of visible light from wax deposited on the cuticle of plant aerial organs. In wheat, two dominant genes lead to non-glaucous phenotypes: Inhibitor of wax 1 (Iw1) and Iw2. The molecular mechanisms and the exact extent (beyond visual assessment) by which these genes affect the composition and quantity of cuticular wax is unclear. To describe the Iw1 locus we used a genetic approach with detailed biochemical characterization of wax compounds. Using synteny and a large number of F2 gametes, Iw1 was fine-mapped to a sub-cM genetic interval on wheat chromosome arm 2BS, which includes a single collinear gene from the corresponding Brachypodium and rice physical maps. The major components of flag leaf and peduncle cuticular waxes included primary alcohols, ß-diketones and n-alkanes. Small amounts of C19-C27 alkyl and methylalkylresorcinols that have not previously been described in wheat waxes were identified. Using six pairs of BC2 F3 near-isogenic lines, we show that Iw1 inhibits the formation of ß- and hydroxy-ß-diketones in the peduncle and flag leaf blade cuticles. This inhibitory effect is independent of genetic background or tissue, and is accompanied by minor but consistent increases in n-alkanes and C24 primary alcohols. No differences were found in cuticle thickness and carbon isotope discrimination in near-isogenic lines differing at Iw1.

Compositional analysis of leaf cuticular membranes isolated from tea plants (Camellia sinensis L.).

Chemical constituents of cuticular membranes (CMs) isolated from three tea cultivars (Camellia sinensis (L.) O. Kuntze cvs. Yabukita, Samidori and Gokou) were compared. All CMs from the adaxial side of the leaves showed higher accumulation of wax, cutin and polysaccharide, while those from the abaxial side were abundant in cutan, showing the adaptation of the adaxial side to abiotic stresses, such as wind and rain, in contrast to the abaxial side, which provides defence against pathogens. Yabukita, a major tea cultivar in Japan, developed thick CMs while Samidori and Gokou, shade-cultivated tea cultivars, had lighter CMs, reflecting their thin and soft leaves. CMs rapidly accumulated 9,10-epoxy-18-hydroxyoctadecanoic acid at a very early stage of leaf development. Additionally, shade treatment did not influence cutin biosynthesis in CMs, reflecting high adaptation of tea leaves under low light levels.