Saturated Fatty Alcohols Research Articles

Two bifunctional enzymes from the marine protist Thraustochytrium roseum: biochemical characterization of wax ester synthase/acyl-CoA:diacylglycerol acyltransferase activity catalyzing wax ester and triacylglycerol synthesis

BackgroundTriacylglycerols (TAGs) and wax esters (WEs) are important neutral lipids which serve as energy reservoir in some plants and microorganisms. In recent years, these biologically produced neutral lipids have been regarded as potential alternative energy sources for biofuel production because of the increased interest on developing renewable and environmentally benign alternatives for fossil fuels. In bacteria, the final step in TAG and WE biosynthetic pathway is catalyzed by wax ester synthase/acyl coenzyme A (acyl-CoA):diacylglycerol acyltransferase (WS/DGAT). This bifunctional WS/DGAT enzyme is also a key enzyme in biotechnological production of liquid WE via engineering of plants and microorganisms. To date, knowledge about this class of biologically and biotechnologically important enzymes is mainly from biochemical characterization of WS/DGATs from Arabidopsis, jojoba and some bacteria that can synthesize both TAGs and WEs intracellularly, whereas little is known about WS/DGATs from eukaryotic microorganisms.ResultsHere, we report the identification and characterization of two bifunctional WS/DGAT enzymes (designated TrWSD4 and TrWSD5) from the marine protist Thraustochytrium roseum. Both TrWSD4 and TrWSD5 comprise a WS-like acyl-CoA acyltransferase domain and the recombinant proteins purified from Escherichia coli Rosetta (DE3) have substantial WS and lower DGAT activity. They exhibit WS activity towards various-chain-length saturated and polyunsaturated acyl-CoAs and fatty alcohols ranging from C10 to C18. TrWSD4 displays WS activity with the lowest Km value of 0.14 μM and the highest kcat/Km value of 1.46 × 105 M−1 s−1 for lauroyl-CoA (C12:0) in the presence of 100 μM hexadecanol, while TrWSD5 exhibits WS activity with the lowest Km value of 0.96 μM and the highest kcat/Km value of 9.83 × 104 M−1 s−1 for decanoyl-CoA (C10:0) under the same reaction condition. Both WS/DGAT enzymes have the highest WS activity at 37 and 47 °C, and WS activity was greatly decreased when temperature exceeds 47 °C. TrWSD4 and TrWSD5 are insensitive to ionic strength and reduced WS activity was observed when salt concentration exceeded 800 mM. The potential of T. roseum WS/DGATs to establish novel process for biotechnological production of WEs was demonstrated by heterologous expression in recombinant yeast. Expression of either TrWSD4 or TrWSD5 in Saccharomyces cerevisiae quadruple mutant H1246, which is devoid of storage lipids, resulted in the accumulation of WEs, but not any detectable TAGs, indicating a predominant WS activity in yeast.ConclusionsThis study demonstrates both in vitro WS and DGAT activity of two T. roseum WS/DGATs, which were characterized as unspecific acyltransferases accepting a broad range of acyl-CoAs and fatty alcohols as substrates for WS activity but displaying substrate preference for medium-chain acyl-CoAs. In vivo characterization shows that these two WS/DGATs predominantly function as wax synthase and presents the feasibility for production of WEs by heterologous hosts.

Chemical reactions in the pyrolysis of brown grease

Brown grease breaks down into a mixture of alkanes and alkenes at temperatures above 300°C without addition of hydrogen or an external catalyst. To better understand the reactions in this process, pyrolysis experiments were performed on palmitic and oleic acids as model systems for the saturated and unsaturated fatty acids in brown grease, respectively. Iron (III) sulfate was used in half of the experiments, as Fe(III) is normally found in brown grease; and the other experiments were performed without iron as controls. In the presence of Fe(III), palmitic acid forms a series of aliphatic hydrocarbons and some palmitone byproduct, while the iron-free control experiment yielded larger quantities of palmitone, up to more than 50%. However, regardless of Fe(III), oleic acid broke down into shorter saturated fatty acids, hydrocarbons, alcohols, aldehydes, esters, and ketones, according to known thermal reactions of unsaturated fatty acids. The product fatty acids then reacted in a manner similar to palmitic acid. The major ketone and alcohol byproducts were also examined for reactions ultimately leading to the desired products.

Tetradecanol reduces EL-4 T cell growth by the down regulation of NF-κB mediated IL-2 secretion

Tetradecanol is a straight-chain saturated fatty alcohol purified from Dendropanax morbifera leaves. We found that tetradecanol (30μM) reduced specifically the growth of T cells such as EL-4 T cell and isolated murine CD4+ T cells. In this study, we investigated the effects of tetradecanol on the regulation of interlukin-2 (IL-2), a potent T cell growth factor. Tetradecanol significantly inhibited IL-2 secretion in EL-4 T cells activated with phorbol 12-myristate 13-acetate (PMA) plus ionomycin (Io) and also in isolated murine CD4+ T cells activated with anti-CD3 and anti-CD28 antibodies. Next, we examined the effect of tetradecanol on the transcriptional activity related to IL-2 production in T cells. Tetradecanol decreased PMA/Io-induced promoter activity of NF-κB in EL-4 T cells, but did not show any significant effects on the promoters of activator protein 1 (AP-1) and nuclear factor of activated T cells (NF-AT). Tetradecanol inhibited IκBα degradation and nuclear translocation of NF-κB subunit, p65 in PMA/Io–activated EL-4 T cells. These results suggest that tetradecanol might have immunosuppressive effects on T cell mediated disorders. Using a chronic allergic contact dermatitis model induced by repeated application of oxazolone, we showed that tetradecanol reduced ear thickness induced by oxazolone.

Wax Ester Fermentation and Its Application for Biofuel Production.

In Euglena cells under anaerobic conditions, paramylon, the storage polysaccharide, is promptly degraded and converted to wax esters. The wax esters synthesized are composed of saturated fatty acids and alcohols with chain lengths of 10-18, and the major constituents are myristic acid and myristyl alcohol. Since the anaerobic cells gain ATP through the conversion of paramylon to wax esters, the phenomenon is named "wax ester fermentation". The wax ester fermentation is quite unique in that the end products, i.e. wax esters, have relatively high molecular weights, are insoluble in water, and accumulate in the cells, in contrast to the common fermentation end products such as lactic acid and ethanol.A unique metabolic pathway involved in the wax ester fermentation is the mitochondrial fatty acid synthetic system. In this system, fatty acid are synthesized by the reversal of β-oxidation with an exception that trans-2-enoyl-CoA reductase functions instead of acyl-CoA dehydrogenase. Therefore, acetyl-CoA is directly used as a C2 donor in this fatty acid synthesis, and the conversion of acetyl-CoA to malonyl-CoA, which requires ATP, is not necessary. Consequently, the mitochondrial fatty acid synthetic system makes possible the net gain of ATP through the synthesis of wax esters from paramylon. In addition, acetyl-CoA is provided in the anaerobic cells from pyruvate by the action of a unique enzyme, oxygen sensitive pyruvate:NADP+ oxidoreductase, instead of the common pyruvate dehydrogenase multienzyme complex.Wax esters produced by anaerobic Euglena are promising biofuels because myristic acid (C14:0) in contrast to other algal produced fatty acids, such as palmitic acid (C16:0) and stearic acid (C18:0), has a low freezing point making it suitable as a drop-in jet fuel. To improve wax ester production, the molecular mechanisms by which wax ester fermentation is regulated in response to aerobic and anaerobic conditions have been gradually elucidated by identifying individual genes related to the wax ester fermentation metabolic pathway and by comprehensive gene/protein expression analysis. In addition, expression of the cyanobacterial Calvin cycle fructose-1,6-bisphosphatase/sedohepturose-1,7-bisphosphatase, in Euglena provided photosynthesis resulting in increased paramylon accumulation enhancing wax ester production. This chapter will discuss the biochemistry of the wax ester fermentation, recent advances in our understanding of the regulation of the wax ester fermentation and genetic engineering approaches to increase production of wax esters for biofuels.

Structure and physical properties of oleogels containing peanut oil and saturated fatty alcohols

This study examined the capability of fatty alcohols with chain lengths from C14OH to C22OH to gel peanut oil. The gelation was achieved by crystallizing the samples at 5°C/min or 40°C/min. Results showed that minimum gelling concentration decreased as fatty alcohol chain length increased and it was higher for fast cooled samples than for the corresponding slow cooled ones. More than 7% of C14OH was necessary to obtain a self‐standing material highlighting its low capacity as oleogelator. Other oleogels were compared at 5% fatty alcohol concentration in peanut oil and oleogels containing C16OH yielded the weakest system, with the lowest ability to retain oil. This was attributed to its higher solubility in oil as compared to other fatty alcohols as well as to the formation of larger crystal aggregates. As the fatty alcohol chain length increased, systems became stronger, displaying smaller crystal aggregates. For all cases, an increase in cooling rate lead to the formation of weaker gels with reduced capacity to entrap oil.Practical applications: A novel strategy to reduce saturated/trans fats in food products involves the use of oleogels. Here we report on the use of even saturated fatty alcohols to gel peanut oil, thus preventing oil separation during storage and handling of products such as nut butters. The structure and physical properties of fatty alcohol oleogels greatly depend on fatty alcohols chain length as well as cooling rate applied during crystallization. Fatty alcohols proved to be a very efficient peanut oil stabilizer.Fatty alcohol chain length and cooling rate greatly affected organogel structure and physical properties.

Fatty alcohol production in Lipomyces starkeyi and Yarrowia lipolytica.

BackgroundCurrent biological pathways to produce biofuel intermediates amenable to separations and catalytic upgrading to hydrocarbon fuels are not cost effective. Previously, oleaginous yeasts have been investigated primarily for lipid production. However, yeasts store neutral lipids intracellularly making recovery difficult and expensive. In addition, once recovered from the cells, lipids are difficult to blend directly with the existing fuels without upgrading. We have, therefore, begun to investigate secreted fatty acid-derived products which can be easily recovered and upgraded to fuels.ResultsIn this study, we successfully demonstrate the production of fatty alcohols by the oleaginous yeasts, Yarrowia lipolytica and Lipomyces starkeyi, through expression of the fatty acyl-CoA reductase gene from Marinobactor aquaeolei VT8. This strategy resulted in the production of 167 and 770 mg/L of fatty alcohols in shake flask from Y. lipolytica and L starkeyi, respectively. When using a dodecane overlay during fermentation, 92 and 99% of total fatty alcohols produced by Y. lipolytica and L. starkeyi, respectively, were extracted into the dodecane phase, which compares favorably to the 3 and 50% recovered, respectively, without the dodecane layer. In both oleaginous yeasts, long chain length, saturated fatty alcohols, i.e., hexadecanol (C16:0) and octadecanol (C18:0), were predominant and accounted for more than 85% of the total fatty alcohols produced. To the best of our knowledge, this is the first report of fatty alcohol production in L. starkeyi. ConclusionThis work demonstrates that the oleaginous yeasts, Y. lipolytica and L. starkeyi, can serve as platform organisms for the production of fatty acid-derived biofuels and bioproducts.

Synthesis of Fatty Acetoacetates Under Microwave Irradiation Catalysed by Sulfamic Acid in a Solvent‐Free System

AbstractThe 1,3‐dicarbonyl compounds are important building blocks to obtain products with various biological activities and technological applications. In this work, we used a simple transesterification method to develop fatty acetoacetates in a solvent‐free medium using a green catalyst, sulfamic acid (NH2SO3H), under microwave irradiation. The experimental results demonstrate good yields in a short reaction time (13 min), which makes this method an efficient approach to synthesize fatty acetoacetates from a wide range of saturated, unsaturated, and polyunsaturated long chain fatty alcohols, and ricinoleic derivatives. Experiments of recycling of the catalyst were performed and no decrease in catalytic activity of sulfamic acid was observed.

Chemical constituents from Ilex urceolatus

Twenty-four compounds were obtained from the extract of the leaves of I. urceolatus, which were divided into saturated fatty alcohols (1 and 2), triterpenoids (3–8 and 14–16), lignanoids (9, 20 and 22), coumarins (10 and 19), flavonoids (11–13, 21, 23 and 24) and others (17 and 18). Among them, compounds 1, 2, 17 and 18 were firstly obtained from the genus Ilex, others were isolated from this species for the first time. The chemotaxonomic relationships between I. urceolatus and other species of genus Ilex were also discussed. As a result, the isolated compounds closely matched the ones obtained in other species of the genus.

Thermal mud maturation: organic matter and biological activity.

Many of the therapeutic and cosmetic treatments offered in spas are centred on mud therapy, to moisturize the skin and prevent skin ageing and rheumatic diseases. Thermal mud is a complex matrix composed of organic and inorganic elements which contribute to its functions. It is a natural product derived from the long mixing of clay and thermal water. During its maturation, organic substances are provided by the microalgae, which develop characteristic of the composition of thermal water. The aim of this study was to identify methods for introducing objective parameters as a basis for characterizing thermal mud and assessing its efficacy. Samples of thermal mud were collected at the Saturnia spa, where there are several sulphureous pools. The maturation of the mud was evaluated by organic component determination using extractive methods and chromatographic analysis (HPLC, GC-MS, SPME). We also studied the radical scavenging activity of mud samples at different stages of maturation, in a homogeneous phase, using several tests (DPPH, ORAC, ABTS). We identified several classes of compounds: saturated and unsaturated fatty acids, hydroxyl acids, dicarboxylic acids, ketoacids, alcohols and others. SPME analysis showed the presence of various hydrocarbons compounds (C(11) -C(17)) and long-chain alcohols (C(12) -C(16)). Six or seven months seemed appropriate to complete the process of maturation, and the main effect of maturation time was the increase of lipids. Six-month mud showed the highest activity. The hydrophilic extract was more active than the lipophilic extract. The results indicate that maturation of thermal mud can be followed on the basis of the changes in its organic composition and antioxidant properties along the time. They also highlight the need to develop reference standards for thermal muds in relation to assess their use for therapeutic and cosmetic purposes.

UV-B辐射增强对拟南芥表皮蜡质的影响

Due to the depletion of stratospheric ozone( O3),the quantity of UV-B radiation reached the earth's surface has increased significantly. Enhanced UV-B radiation influenced plant growth,development and productivity by damaging DNA,RNA,and proteins. Plants are thought to employ a variety of UV-B protective mechanisms,including accumulation of a range of secondary metabolites and adaptive changes in plant morphological features. As the outer surface of aerial plant tissues,the epicuticular wax is believed to play an important role in protecting plants against ultraviolet-B radiation.Epicuticular wax was composed primarily of saturated free fatty acids,aldehydes,alkanes,primary alcohols,secondary alcohols,ketones,and wax esters. Arabidopsis,as a model system to study the genetics and the molecular biology,has the typical structure and composition of cuticle,and it should be a model system to study the ecology of epicuticular waxes.However,little is known as to the responsees of different wax constituents to enhanced UV-B radiation,and the role of epicuticular waxes in providing protection for Arabidopsis from UV-B has not been examined either. Therefore,in the current study,seven wax mutants( CER1,CER3,CER4,CER6,CER10,CER20 and KCS1) and wild type of A. thaliana were selected to analyze the responses of epicuticular wax in crystalloid structure,content and constituents,and wax related gene to UV-B radiation( 50 μW / cm2). The plants accepted UV-B radiation 2 h every day for consecutive 10 days. The resultsshowed that enhanced UV-B radiation altered the crystalloid structure of epicuticular wax on Arabidopsis stems. Under the enhanced UV-B radiation,amounts of pine needle-shaped crystalloids( CER1),columnar-shaped crystalloids and rods( CER3、CER10 and KCS1) decreased significantly. Some small globular-shaped crystalloids appeared on the surface of CER6 mutant. Some irregular plate- and membrane-shaped structures covered the surface of KCS1 and CER10. No significant change of crystalloid types was observed on the stem of the Arabidopsis wild type; however,many horizontal rod and tube crystalloids accumulated in specific zones,which increased the thickness of cuticle. Enhanced UV-B radiation also altered the secretion quantities of wax constituents. Under UV-B radiation,the contents of primary alcohols,fatty acids and aldhydes in Arabidopsis wild type increased significantly,the contents of alkanes,secondary alcohols and ketones decreased significantly,while the contents of total wax changed insignificantly. Under UV-B radiation,the increase of primary alcohols and the decrease of secondary alcohols and ketones were universal in Arabidopsis mutants. Enhanced UV-B radiation upregulated the expression of CER3,CER4 and KCS1,which promoting the accumulation of primary alcohols,fatty acids and aldehydes. The decreased expression of CER1 under UV-B radiation might lead to the reduction of products from alkanesynthesizing branch of the pathway,including alkanes,secondary alcohols and ketones. The decreased expression of WIN1 under UV-B radiation had no effect on the content of total wax,implying that the accumulation of total wax was a result of comprehensive effects of multi genes involved in wax synthesis pathway. Enhanced UV-B radiation shunted wax precursors away from the alkane-synthesizing branch to primary alcohol branch of the pathway.

Contribution to Understanding the Occurrence of Extractives in Red Heart of Beech

Common beech (Fagus sylvatica) is one of the deciduous tree species characterized by the formation of a discolored red heart in the central part of the stem. The aim of this work was to review data in existing literature and to present original results on the extractives present in sapwood and the red heart of beech. Samples of sapwood and red heart were taken from freshly felled beech trees and extracted with a speed extractor. The content of lipophilic and hydrophilic extractives was determined gravimetrically and further evaluated by gas chromatography. The beech wood contained, on average, 1.04% lipophilic and 3.71% hydrophilic extractives. Even though the gravimetrically determined content of lipophilic extractives was comparable in the sapwood and the red heart, saturated fatty acids, fatty alcohols, and free sterols were dominant in the red heart. Sapwood contained a larger amount of total hydrophilic extractives. Mono- and oligosaccharides, sugar acids and alcohols, carboxylic acids, simple phenols, and flavonoids were identified as the prevailing hydrophilic solubles in sapwood, whereas the concentration of sugar alcohols was higher in the red heart. The composition and character of the extractives in the wood of red-hearted beech should be considered the relevant technological factor.

Antioxidant Properties and Efficacies of Synthesized Alkyl Caffeates, Ferulates, and Coumarates

Caffeic, ferulic, and coumaric acids were lipophilized with saturated fatty alcohols (C1-C20). The antioxidant properties of these hydroxycinnamic acids and their alkyl esters were evaluated in various assays. Furthermore, the antioxidant efficiency of the compounds was evaluated in a simple o/w microemulsion using the conjugated autoxidizable triene (CAT) assay. All evaluated phenolipids had radical scavenging, reducing power, and metal chelating properties. Only caffeic acid and caffeates were able to form a complex with iron via their catechol group in the phenolic ring. In the o/w emulsion, the medium chain phenolipids of the three homologues series were most efficient. The antioxidant properties and efficacies were dependent upon functional groups substituted to the ring structure and were in the following order: caffeic acid and caffeates > ferulic acid and ferulates > coumaric acid and coumarates. Moreover, the results demonstrated that the test system has an impact on the antioxidative properties measured.

Distinctive lipid composition of the copepod Limnocalanus macrurus with a high abundance of polyunsaturated fatty acids.

We studied the copepod Limnocalanus macrurus for seasonal variation in the composition of fatty acids, wax esters and sterols in large boreal lakes, where it occurs as a glacial-relict. Vast wax ester reserves of Limnocalanus were accumulated in a period of only two months, and comprised mono- and polyunsaturated fatty acids (PUFA) and saturated fatty alcohols. In winter, the mobilization of wax esters was selective, and the proportion of long-chain polyunsaturated wax esters declined first. PUFA accounted for >50% of all fatty acids throughout the year reaching up to ca. 65% during late summer and fall. Long-chain PUFA 20:5n-3 and 22:6n-3 together comprised 17-40% of all fatty acids. The rarely reported C24 and C26 very-long-chain PUFA (VLC-PUFA) comprised 6.2 ± 3.4 % of all fatty acids in August and 2.1 ± 1.7% in September. The VLC-PUFA are presumably synthesized by Limnocalanus from shorter chain-length precursors because they were not found in the potential food sources. We hypothesize that these VLC-PUFA help Limnocalanus to maximize lipid reserves when food is abundant. Sterol content of Limnocalanus, consisting ca. 90% of cholesterol, did not show great seasonal variation. As a lipid-rich copepod with high abundance of PUFA, Limnocalanus is excellent quality food for fish. The VLC-PUFA were also detected in planktivorous fish, suggesting that these compounds can be used as a trophic marker indicating feeding on Limnocalanus.

On the solid–liquid phase diagrams of binary mixtures of even saturated fatty alcohols: Systems exhibiting peritectic reaction

Abstract The solid–liquid phase diagrams of the following binary mixtures of even saturated fatty alcohols are reported in the literature for the first time: 1-octanol (C8OH) + 1-decanol (C10OH), 1-decanol + 1-dodecanol (C12OH), 1-dodecanol + 1-hexadecanol (C16OH) and 1-tetradecanol (C14OH) + 1-octadecanol (C18OH). The phase diagrams were obtained by differential scanning calorimetry (DSC) using a linear heating rate of 1 K min−1 and further investigated by using a stepscan DSC method. X-ray diffraction (XRD) and polarized light microscopy were also used to complement the characterization of the phase diagrams which have shown a complex global behavior, presenting not only peritectic and eutectic reactions, but also the metatectic reaction and partial immiscibility on solid state.

Rice Consumption Is Associated with Better Nutrient Intake and Diet Quality in Adults: National Health and Nutrition Examination Survey (NHANES) 2005-2010

Objectives: The goal of this study was to determine the association of rice consumption with nutrient intake and diet quality in a recent nationally representative sample of US adults. Methods: NHANES data (2005-2010) were used to assess the association of rice consumption by adults (19+ yrs; N = 14,386) with nutrient intake and diet quality. 24-hour dietary intakes were used to calculate usual intake (UI) of rice consumption using the National Cancer Institute methodology. Rice consumption groups were 0.25 to 0.5 to 1.0 oz. eq. of UI of rice. Diet quality (using the Healthy Eating Index-2005 [HEI-2005]) was calculated. Covariate adjusted least square means ± SE were determined and quartile trends across the rice consumption categories were examined. Results: Significant (p < 0.001) positive trends (β coefficient across rice consumption categories) were seen for sodium (118.99 mg), dietary fiber (0.57 g), folate (58.24 μg DFE), magnesium (11.83 mg), iron (0.97 mg) and potassium (29.45 mg). Significant negative trends (p < 0.0001) were seen for intakes of saturated fatty acids (－1.75 g), added sugars (－1.31 g); and calcium (－40.46 mg). HEI-2005 also showed a positive trend (p < 0.0001) with rice consumption (5.5 points). HEI-2005 component scores for total fruit (0.07), whole fruit (0.11), dark green/orange vegetables (0.25), total grains (0.10), meat/beans (0.24), and oils (0.15) were higher (p < 0.01) in rice consumers than non-consumers. HEI-2005 component scores for saturated fatty acids (0.63), solid fats, added sugars, and alcohol (1.22) were higher suggesting more favorable intake, but sodium (－0.24) was lower. Conclusion: Overall, consumption of rice should be encouraged to improve nutrient intake and diet quality. Nutrition education can provide ways to reduce sodium added to rice dishes.

Can natural products serve as potential treatments for osteoarthritis?

Can natural products serve as potential treatments for osteoarthritis?

Research on the Influence of the Type of Surfactant and Concentrator in Aqueous Dispersion of Pigments.

This work reports tests performed to evaluate the stability of aqueous dispersions of inorganic oxide pigments with different specific surface areas, with the use of anionic and non-ionic surfactants and concentrators. Color mixtures of oxide compounds of blue, green, olive and brown with the unit cell spinel structure were used as pigments. The sodium salt of sulfosuccinic acid monoester, oxyethylenated nonylphenol and ethoxylated derivatives of lauryl alcohol, fatty alcohol and fatty amine were used as surfactants. The concentrators used were: poly(vinyl alcohol), the sodium salt of carboxymethyl cellulose as well as a water-based polyurethane oligomer. The highest dispersion efficiency was found for dispersed systems in which surfactant and concentrator were incorporated in the formula. The one containing the sodium salt of carboxymethyl cellulose or polyurethane oligomer with ethoxylated saturated fatty alcohol or fatty amine was found to be the most efficient. It was discovered that a higher dispersion efficiency corresponds to pigments with larger specific surface. The efficiency is also found to improve when the concentrator is an acrylic polymer or copolymer made up of two acrylic species. In this case, the concentrator interaction with the surfactant is more effective if the value of its boundary viscosity number is higher. This observation confirms the existence of interactions between macro-chains of the concentrator and surfactant molecules forming micelles with the pigment particles.

New methods in biomass depolymerisation: catalytic hydrogenolysis of barks

Hydrogenolysis of bark from three different species of tree using heterogeneous platinum group metal catalysts produces two major product streams. Aromatic substituted guaiacols are produced from lignin and the lignin-like regions of suberin and a range of saturated fatty acids and alcohols, including α,ω-functionalised species, are produced from the polyester regions of suberin. Control experiments demonstrate clear advantages of catalytic hydrogenolysis over base hydrolysis, both in terms of conversion and product selectivity.

Ultrastructural and chemical studies on waxy secretions and wax-producing structures on the integument of the woolly oak aphid Stegophylla brevirostris Quednau (Hemiptera: Aphididae)

The woolly oak aphid (WOA), Stegophylla brevirostris Quednau, is a recently described oak pest in Florida, USA. Colonies of WOA on live-oak trees are distinguished by a thick layer of white filamentous waxy material covering most individuals. Nymphs and apterous adults have several long waxy threads/bundles extending from their head, thorax and especially from their abdomen. We used scanning electron microscopy of ‘naturally waxed’ and ‘dewaxed’ aphids to study the ultrastructure and distribution of wax-producing structures on the cuticle. Two types of ‘wax pores’ and smaller wax ‘pits’ were found clustered in wax pore plates around dorsal setae on the head, thorax and abdomen. The larger, type-1, wax pores produce short or long wax columns with honeycomb interior; the smaller, type-2, wax pores produce short or long hollow wax tubes; whereas wax pits produce the shorter and more loosely net tufts of wax filaments covering most of the body dorsally. Wax columns or tubes produced by clusters of types-1 and 2 wax pores aggregate together forming the longer and thicker wax bundles that extend dorsally and laterally from the cuticle, especially near the posterior end of the abdomen. Type-2 wax pores and wax pits were also found on parts of the legs and antennae. Infrared spectroscopy indicated that wax esters, containing saturated fatty acids and fatty alcohols, are the major constituents of WOA waxy secretions. The possible roles of these secretions, especially in avoiding contamination with honeydew and providing some protection against natural enemies and adverse climatic conditions, are discussed.

Spectroscopic and chromatographic evaluation of the wax ester fraction of Adenanthera pavonina oil

Present study was carried out in order to assess the constituents of Adenanthera pavonina wax esters by Fourier Transform Infrared (FT-IR) spectroscopy and Gas chromatography (GC). After extraction of oil from A. pavonina seeds, wax esters were separated from oil by centrifugation and then purified through crystallization process in acetone. The white crystalline solid with melting point of 83–85°C was initially characterized as wax esters by FT-IR. Gas chromatography with flame ionization detector (GC-FID) provided the separation of various wax esters from C34 to C48 including odd and even chain esters. C46 wax ester was found to be predominant. For separation, identification and estimation of individual constituents of fatty acid methyl esters and fatty alcohol acetates were carried out by GC–MS after saponification and derivatization of wax esters. GC–MS analysis indicated the presence of saturated methyl esters from Cl4 to C30. Predominant methyl ester was C22. Wax esters contained the saturated fatty alcohols from C14 to C28. The major alcohol was saturated C24 fatty alcohol. The results indicated that A. pavonina wax esters have potential to be used in pharmaceutical and cosmetic industry due to its better composition of long chain fatty acids and fatty alcohols.