Epicuticular wax of Agropyron intermedium

Wax on leaves of Agropyron intermedium contains hydrocarbons (11%, C₂₇–C₃₃), esters (11%, C₃₂–C₆₀), free alcohols (180%, C₂₆) 25-oxohentriacontane-14,16-dione (17%), 10-oxohentriacontane-14,16-dione (5y%), 25-hydroxyhentriacontane-14,16-dione (12%) and 26-hydroxyhentriacontane-14,16-dione (2%). Wax on spikes contains additional components, C₂₅–C₃₃cis 9-alkenes (32% of hydrocarbons), and more β-diketones, 25-hydroxy (17%) and 26-hydroxy (3%) hentriacontane-14,16-diones, 10,25-dioxohentriacontane-14,16-dione (1%) and 4-hydroxy-25-oxo-(2%), 25-hydroxy-10-oxo-(1.3%) and 26-hydroxy-10-oxo-(0.7%) hentriacontane-14,16-diones; free alcohols were very minor components (1%, C₂₄–C₃₂).     

Epicuticular waxes from Agropyron dasystachyum,agropyron riparium and Agropyron elongatum

Epicuticular waxes from whole plants of Agropyron dasystachyum var. psammophylum, A. riparium and A. elongatum contain hydrocarbons (5–8 %), long chain esters (12–15%) and free acids (2–5%). The major esters are C₃₄C₅₆ esters derived from C₁₆C₃₀ acids and alcohols (1-hexacosanol is the major alcohol) but C₃₁, C₃₃ and C₃₅ esters (3–11%) are also present. The latter esters are C₁₈ and C₂₀ acid esters of C₁₃ and C₁₅ 2-alkanols. A. dasystachyum wax contains 2% free alcohols, that of A. riparium contains 17% and that of A. elongatum 11% (1-hexacosanol is the major alcohol in each). Diesters (2%), C₈C₁₂ diols esterified by (E)-2-alkenoic acids, are present in A. riparium wax. Hentriacontane-14,16-dione is present: 29% in A. dasystachyum wax and 32% in A. riparium wax, but only 5% in A. elongatum wax. 25-Oxohentriacontane-14,16-dione forms 14% of A. dasystachyum wax and 27% of A. elongatum wax but the oxo β-diketones of A. riparium wax (5%) consist of both 10-oxo- and 25-oxohentriacontane-14,16-diones in the ratio 4:1. Hydroxy β-diketones of the waxes are 25- and 26-hydroxyhentriacontane-14,16-diones; in A. dasystachyum (20%) the ratio is 3:1, in A. elongatum (20%) the ratio is 9:1 but in A. riparium (5%) it is ca 1:2. The configuration of the hydroxyl group in the 26-hydroxy β-diketone is opposite to that in the 25-hydroxy derivative. The unusual composition of the oxygenated β-diketones of A. riparium confirms that this species should be regarded as separate from A. dasystachyum. Wax from A. elongatum also contains 4-hydroxy-25-oxohentriacontane-14,16-dione (4%) and an unusual oxo-β-ketol, 18-hydroxy-7,16-hentriacontanedione (2%), both these components are probably derived biosynthetically from the 25-oxo β-diketone which is the major component of this wax. Syntheses of racemic 18-hydroxy-7,16-hentriacontanedione and of a model β-ketol, 12-hydroxy-10-pentacosanone, are described.     

Epicuticular waxes of Secale cereale and Triticale hexaploide leaves

Wax on leaves of rye and of hexaploid Triticale (60–70-day-old plants) contains hydrocarbons (6–8%), esters (10%), free alcohols (14-8%), free acids (3%), hentriacontane-14,16-dione (39–45%), 25 (S)-hydroxyhentriacontane-14,16-dione (13–11%) and unidentified (14–15%). Diesters (1–3%) are also present in rye wax. Compositions of hydrocarbons (C₂₇-C₃₃) and esters (C₂₈,C₅₈) are similar for both waxes. Free and combined alcohols of rye wax are mainly hexacosanol but alcohols of Triticale wax are mainly octacosanol. The composition of Triticale wax is close to that of its wheat parent Triticum durum (cv. Stewart 63). Esters of wax from ripe rye contain 58% of trans 2,3-unsaturated esters. *NRCC No. 14033.     

Epicuticular waxes of Andropogon hallii and A. Scoparius

Leaf waxes of Andropogon hallii and A. scoparius contain hydrocarbons (2%, 2%), esters (4%, 2%), free acids (3%, 4%), free alcohols (1%, 0.2%, major component dotriacontanol) β-diketones (67%, 80%) and hydroxy β-diketones (16%, 5%). β-Diketones of A. hallii consist mainly of tritriacontane-12,14-dione and hentriacontane-12,14-dione (86:8) and of A. scoparius of tritriacontane-12,14-dione and hentriacontane-10,12-dione (67:29). Hydroxy β-diketones of A. hallii are composed mainly of 5-hydroxytritriacontane-12,14-dione and 5-hydroxy-hentriacontane-12,14-dione (90:8); wax of A. scoparius contains only 5-hydroxytritriacontane-12,14-dione. The hydroxyl group of the major hydroxy β-diketone has the R-configuration opposite to that of all previously described hydroxy β-diketones.     

Epicuticular wax of Panicum virgatum

Leaf and stem wax of Panicum virgatum contains hydrocarbons (4%), esters (3%), free acids (2%), free alcohols (1%), triterpene alcohols (2%), β-diketones (69%) and hydroxy β-diketones (6%). Principal free alcohols range in chain length from C₂₆ to C₃₂. β-Diketones consist almost entirely of tritriacontane-12,14-dione and the hydroxy β-diketone consists only of 5(S)-5-hydroxytritriacontane-12,14-dione. The configuration of the hydroxyl group is the same as that of hydroxy β-diketones from festucoid grasses but opposite to that of the hydroxy β-diketone from Andropogon species.     

Leaf wax of Triticum aestivum

Leaf waxes from spring wheat varieties Selkirk and Manitou contain hydrocarbons (6%, 10%), long chain esters (14%, 13%), free acids (5%, 8%), free alcohols (19%, 21%), β-diketone (16%, 20%), hydroxy β-diketones (8%, 10%), unidentified gum (29%, 16.5%) and minor amounts of diol diesters, glycerides and aldehydes. The major hydrocarbon is nonacosane and major esters are octacosyl esters of C₁₄–C₃₂ acids but C₂₀ and C₂₂ alcohol esters of trans 2-docosenoic and tetracosenoic acids are also present (Selkirk 20%, Manitou 10% of total esters). Previously unknown trans 2-docosen-1-ol is present as an ester (Selkirk 5%, Manitou 2.5% of total esters). Free acids are C₁₄–C₃₂ acids and trans 2-docosenoic and tetracosenoic acids (Selkirk 30%, Manitou 9% of free acids). Octacosanol is the principal free alcohol. Hentriacontane-14,16-dione is the β-diketone and the hydroxy β-diketones are a 1:1 mixture of 8- and 9- hydroxyhentriacontane-14,16-diones.     

Biosynthesis of the beta-diketones of barley spike epicuticular wax.

[1-¹⁴C]acetate and [2-¹⁴C]acetate were incorporated into the β-diketones of barley spike epicuticular wax via the peduncle. Utilizing column chromatography with dry copper acetate, the β-diketones were isolated and the labeling pattern in the hentriacontan-14, 16-dione determined after its degradation. A modified iodoform procedure was used to give myristic and palmitic acids. Radio-gas chromatography was then performed on the products of chemical α-oxidation of the separated fatty acids. This procedure, in effect, gave the specific activity of every carbon atom of hentriacontan-14,16-dione except carbon-1 to carbon-5 (from myristic acid) and carbon-27 to carbon-31 (from palmitic acid) for each labeled substrate. The specific activity of carbon-15 was determined by an indirect method. On the basis of these data it is suggested that the hentriacontan-14,16-dione is synthesized from the carbon-31 end of the molecule by elongation as follows. C₂ units are added, perhaps to a mixture of short chain precursors, to give a chain with 12 carbon atoms. This chain is then elongated to one with 16 carbon atoms so that the four added carbon atoms are uniformly labeled. Following this, the chain with 16 carbon atoms is elongated with C₂ units to give the complete molecule. Possibly some change in mechanism occurs in this last elongation process when the chain is 22 carbon atoms long. Barley spike wax β-diketones contain about 2% nonacosan-13, 15-dione which seems to be synthesized in an analogous manner.     

Chemical Composition and Recrystallization of Epicuticular Waxes: Coiled Rodlets and Tubules

Abstract: Coiled rodlets characterize several non-related taxa within the angiosperms. They often occur together with tubules but sometimes also with platelets or transitional forms between them. The ultrastructure chemistry, and recrystallization of epicuticular waxes of three species were investigated by high-resolution scanning electron microscopy, gas chromatography, and mass spectrometry. Whereas Buxus sempervirens (Buxaceae) and Chrysanthemum segetum (Asteraceae) show coiled rodlets in combination with tubules, Leymus arenarius (Poaceae) exhibits tubules but no coiled rodlets. Chemical analyses reveal that the predominating β-diketones of all species differ completely in their molecular structure. Those of the former two species are mainly substituted in carbon atom positions up to 12. In contrast, the wax of L. arenarius contains only hentriacontane-14,16-dione and 25-hydroxy-hentriacontane-14,16-dione. Standard solutions of the total waxes from B. sempervirens, C. segetum and L. arenarius, the purified β-diketone fraction from C. segetum and hentriacontane-14,16-dione from Secale cereale were taken for recrystallization experiments under different conditions in relation to solvent and crystallization velocity. It was demonstrated that coiled rodlets grew exclusively from total waxes of B. sempervirens and C. segetum, and its β-diketone fraction but never from L. arenarius wax or pure hentriacontane-14,16-dione. The recrystallization experiments pointed out that conditions, such as the chemical environment and physical factors, strongly influence the formation of coiled rodlets and tubules. It is concluded that coiled rodlets are formed by self-assembly in close dependence on the position of β-diketo substitution. The future role of β-diketones in the classification of coiled rodlets within wax crystals is discussed.     

Epicuticular wax of Eragrostis curvula

Epicuticular wax of Eragrostis curvula contains hydrocarbons (6%), esters (13%), acids (3%), alkanols (4%), tritriacontane-12,14-dione (47%), 5(S)-5-hydroxytritriacontane-12,14-dione (14%) as major components. The esters consist of triterpenol esters (42%) as well as alkanol esters. The free alkanols consist principally Of C₁₆C₃₂ components, resembling those of waxes from panicoid, and some other eragrostoid, grasses. Minor components are triterpenols (0.7%), triterpenones (0.5%), triacylglycerols (0.3%), secondary alkanols (0.1%) and 5-oxotritriacontane-12,14-dione (0.1%).     

Epicuticular waxes of four eragrostoid grasses

The major components of Sporobolus airoides wax were hydrocarbons (37%, C₂₇–C₃₃), those of Bouteloua curtipendula and Eragrostis trichoides waxes esters (28% and 31%, respectively) and those of Muhlenbergia wrightii wax free alcohols (57%, almost entirely C₂₈). Free alcohols formed 22% of the wax from B. curtipendula, 19 % of the wax from E. trichoides and 10% of the wax from S. airoides; the compositions ranged from C₂₆ to C₃₂ with C₃₂ the major component. These alcohol compositions are similar to those found for other species in the subfamily Eragrostoideae. The esters contain 32–46% of acylated triterpenols, principally α- and β-amyrins. Aldehydes were present in all the waxes except for that from S. airoides.     

Biosynthetic relationships between β-diketones and esterified alkan-2-ols deduced from epicuticular wax of barley mutants

Summary The synthesis and deposition of the epicuticular waxes in barley are determined by the eceriferum (cer) loci. On the uppermost internodes, leaf sheaths and spikes of the wild type Bonus, the -diketones and hydroxy--diketones (almost entirely hentriacontan-14,16-dione and 25-hydroxyhentriacontan-14,16-dione, respectively) are the predominating wax classes. In these same waxes esters containing alkan-2-ols (primarily tridecan-2-ol and pentadecan-2-ol) are present. Analyses of the -diketone content and ester composition of waxes from Bonus and eight cer mutants led to the hypothesis that these two wax classes are synthesized from common precursors, namely C₁₄ and C₁₆ chain elongation intermediates. Subsequently, decarboxylation with a simultaneous retention of the carbonyl groups in the -position would lead to the esterified alkan-2-ols while retention of two carbonyl groups plus further elongation would lead to the -diketones. This closer biosynthetic relationship of the -diketones to the esterified alkan-2-ols than to the other lipid classes-hydrocarbons, alkan-1-ol containing esters, aldehydes, alkan-1-ols and free acids—found in all barley waxes is illustrated schematically and the approximate sites of action of the cer loci indicated.     

Epicuticular wax of Pinus radiata needles

Epicuticular wax isolated from the cotyledons and primary needles of 10-week-old Pinus radiata seedlings is similar in composition and contains 86% neutral compounds, viz. alkyl esters (25%, C₂₄–C₆₄), nonacosan-10-ol (52%), heptacosane-5,10-diol (2%), nonacosane-4,10-diol, nonacosane-5,10-diol, and nonacosane-10,13-diol (total 12%) and estolides, MW ca 800 (2%), MW ca 1100 (6%), and MW ca 1500 (1%). The acidic fraction (14%) contains n-acids (78%, C₁₂–C₃₂) and diterpene acids (22%, mainly abieta-8,11,13-trien-18-oic, with lesser amounts of pimara-8(14),15-dien-18-oic, isopimara-7,15-dien-18-oic and hydroxylated aromatic, diene and mono-ene acids). Wax isolated from primary needles of 1-yr-old seedlings had a similar neutral fraction composition, but the acidic fraction contained predominantly the diterpene acid mixture, with only trace amounts of n-acids. The wax from 1-yr-old secondary, needles from P. radiata forest trees aged 5 yr and 40 yr contained an acid fraction (12% 5 yr, 17% 40 yr trees) comprising the diterpene acid mixture, with trace amounts of n-acids together with ω-hydroxy acids (C₁₂, C₁₄ and C₁₆). The neutral fraction from both young and old trees had a similar composition containing alkyl esters (7%, C₂₄–C₆₆), estolides (90%, MW 566-ca 1500), nonacosan-10-ol (2%) and the heptacosane and nonacosane diols (1%). During growth and maturation of P. radiata, the nonacosan-10-ol content of the needle wax decreases while the proportion of estolides and diterpene acids increases, the latter probably being located around the stomatal pore.     

Wax composition of sargassum fulvellum

Sixty-seven compounds were characterized in the wax of Sargassum fulvellum. Characteristic components were the 5-methylhexyl esters of octanoic, decanoic, lauric, myristic, palmitic, palmitoleic, stearic, oleic, linoleic and linolenic, and the 2-ethylhexyl esters of the same acids. The wax of S. fulvellum contains hydrocarbons (1.6%), esters (21.8%), free acids (74.9%) and free alcohols (0.3%). The principal free alcohols range in chain length only from C₆ to C₇.     

Synthesis of β-hydroxy fatty acids and β-amino fatty acids by the strains of Bacillus subtilis producing iturinic antibiotics

The iturinic antibiotics, which contain long chain β-amino acids, are produced by Bacillus subtilis. Screening these strains for the presence of a possible precursor of the iturinic antibiotics, we isolated a lipopeptide containing β-hydroxy fatty acids. The structure of this compound was studied and it appears to be identical or structurally very similar to surfactin. The carbon chain of its β-hydroxy fatty acids was n C₁₆, iso C₁₆, iso C₁₅ or anteiso C₁₅. The percentages of each β-hydroxy fatty acids varied according to the strain producing iturinic antibiotics and were influenced by addition of branched-chain α-amino acids to the culture medium. These results demonstrate for the first time that iso C₁₄ β-hydroxy fatty acid is a constituent present in such a surfactin like lipopeptide. Besides, the presence of radioactive β-hydroxy fatty acids in the phospholipids when the strains were grown in the presence of sodium [¹⁴C]acetate seems also characterize the different strains producing iturinic antibiotics.     

Composition of leaf surface waxes of Triticum species: Variation with age and tissue

The composition of cuticular wax from plants of spring wheat (varieties Selkirk and Manitou) and of durum wheat (variety Stewart 63) at various stages of growth, and of wax from different parts of the plants varies considerably. Wax was analysed, without preliminary separation, by GLC using Dexsil 300 as liquid phase. Alcohols are major components of wax from leaf blades and β-diketones are major components of wax from leaf sheaths, especially the flag leaf sheath. Glaucousness of the leaf sheath is due to the high β-diketone content. In the first 50 days after germination, before sheaths and flag leaf are completely developed, the major component is octacosanol (> 50%). At 66 days, when sheath development is complete, β-diketone content is greatest. Hydrocarbon composition differs for wax from leaf blade and leaf sheath and also for different leaf blades and between adaxial and abaxial sides of the flag leaf. From 66 to 100 days ester content of wax increases, especially in Selkirk wheat, apparently due to formation of wax containing high proportions of esters of trans-α,β-unsaturated C₂₂ and C₂₄ acids. The content of these acids in the free fatty acids and of diesters based on these acids also increases during this period.     

Chemical constituents from Psychotria arborea Hiern (Rubiaceae)

The chemical study of the stems extract of Psychotria arborea Hiern led to the isolation of thirteen compounds, including four anthraquinones: 2-methylanthracene-9,10-dione (1), 2-methoxyanthracene-9,10-dione (2), 2-hydroxy-3-methylanthracene-9,10-dione (3) and 3-hydroxy-1-methoxy-2-methylanthracene-9,10-dione (4); two diterpenes: ent-kaur-16-en-19-oic acid (5) and 15-acetoxy-ent-kaur-16-en-19-oic acid (6); two triterpenes, β-amyrin (8) and oleanolic acid (9), one flavonoid: Quercetin (7), three sterols: A mixture of stigmasterol (10) and β-sitosterol (11) and β-sitosterol-3-O-β-D-glucopyranoside (12) and one fatty acid (13). The structures of these compounds were elucidated based on NMR and HR-ESIMS analysis, further supported by comparison with previously reported spectral data. Compounds 1–4 and compounds 10–12 were tested for their antibacterial activity against three bacteria strains Escherichia coli, Staphylococcus aureus and Salmonella enterica. All these tested compounds were found to be inactive. Furthermore, the chemotaxonomic significance of the obtained compounds was discussed in detail.     

Surface wax of Andreaea and Pogonatum species

The mosses Andreaea rupestris, Pogonatum aloides and P. urnigerum contain surface waxes in amounts of 0.05–0.12% dry wt. The waxes consisted of esters (C₃₈-C₅₄), primary alcohols (C₂₀-C₃₂), free fatty acids (C₁₆-C₃₀), and alkanes (C₂₁-C₃₁). Additionally, aldehydes (C₂₂-C₃₀) were major constituents in the wax of P. urnigerum. The classes and their chain length distributions in the surface waxes of these mosses are comparable to those of epicuticular waxes of higher plants.     

Phospholipid and acid composition of Nocardia and nocardoid bacteria as criteria of classification

Phospholipid and acid composition of 5 strains of ‘true’ Nocardia and 4 strains of nocardoid bacteria have been studied. A great homogeneity was found in all the Nocardia species: phospholipids consist of cardiolipin, phosphatidyl ethanolamine, phosphatidylinositol and phosphatidylinositol mannoside. Streptomyces (Nocardia) mediterranei did not contain phosphatidylinositol and Oerskovia (Nocardia) turbata had no phosphatidyl ethanolamine. The fatty acid composition of these phospholipids was determined and was found different in Nocardia and nocardoid species. Nocardia were rich in straight chain fatty acids and tuberculostearic acid while the phospholipids of nocardoid bacteria contained greater amounts of branched fatty acids. The fatty acids from acetone soluble lipids consisted of hydroxy and non-hydroxy compounds. Hydroxy acids were found in Nocardia which contained nocardic acids: high MW β-hydroxy α-branched acids and in S. mediterranei which contained β-hydroxy acids with 15–17 carbon atoms. Non-hydroxy acids were essentially palmitic and tuberculostearic acids in Nocardia species while S. mediterranei and O. turbata contained great amounts of iso acids from C₁₄ to C₁₇. Phospholipid and acid composition are discussed as criteria of taxonomic classification of Nocardia and related Actinomycetes.     

Hydroxylation of DHEA and its analogues by Absidia coerulea AM93. Can an inducible microbial hydroxylase catalyze 7α- and 7β-hydroxylation of 5-ene and 5α-dihydro C19-steroids?

In this paper we focus on the course of 7-hydroxylation of DHEA, androstenediol, epiandrosterone, and 5α-androstan-3,17-dione by Absidia coerulea AM93. Apart from that, we present a tentative analysis of the hydroxylation of steroids in A. coerulea AM93. DHEA and androstenediol were transformed to the mixture of allyl 7-hydroxy derivatives, while EpiA and 5α-androstan-3,17-dione were converted mainly to 7α- and 7β-alcohols accompanied by 9α- and 11α-hydroxy derivatives. On the basis of (i) time course analysis of hydroxylation of the abovementioned substrates, (ii) biotransformation with resting cells at different pH, (iii) enzyme inhibition analysis together with (iv) geometrical relationship between the C–H bond of the substrate undergoing hydroxylation and the cofactor-bound activated oxygen atom, it is postulated that the same enzyme can catalyze the oxidation of C₇-H_α as well as C₇-H_β bonds in 5-ene and 5α-dihydro C₁₉-steroids. Correlations observed between the structure of the substrate and the regioselectivity of hydroxylation suggest that 7β-hydroxylation may occur in the normal binding enzyme-substrate complex, while 7α-hydroxylation—in the reverse inverted binding complex.