Surface Wax Research Articles

Role of surface wax alkanes from Lathyrus sativus L. seeds for attraction of Callosobruchus maculatus (F.) (Coleoptera: Bruchidae)

Callosobruchus maculatus (Fabricius) (Coleoptera: Bruchidae) is an important pest of Lathyrus sativus L. seeds, commonly known as khesari, in Bangladesh, Ethiopia, and India. Extraction, thin layer chromatography, and gas chromatography–mass spectroscopy analyses of surface waxes of four varieties, i.e., Bio L 212 Ratan, Nirmal B-1, WBK-14-7, and WBK-13-1 of khesari seeds revealed 17, 17, 18, and 17 n-alkanes ranging between n-C15 and n-C32. Nonadecane was the predominant n-alkane, accounting for 814.2, 770.1, 686.1, and 836.7 μg in Bio L 212 Ratan, Nirmal B-1, WBK-14-7, and WBK-13-1 khesari seeds, respectively. Triacontane, dotriacontane, hexadecane, and dotriacontane were the least abundant alkanes in Bio L 212 Ratan, Nirmal B-1, WBK-14-7, and WBK-13-1 khesari seeds, representing for 48.6, 68.6, 50.4, 56.3 μg, respectively. Callosobruchus maculatus females elicited attraction to the surface wax alkanes of Bio L 212 Ratan, Nirmal B-1, WBK-14-7, and WBK-13-1 khesari seeds and mixtures of synthetic alkanes mimicking surface wax alkanes of four varieties of khesari seeds at the minimum concentrations of 4, 4, 6, and 4 μg, respectively, in a glass Y-tube olfactometer bioassay. The insect was attracted to individual synthetic octadecane, nonadecane, heneicosane, tricosane, pentacosane, and dotriacontane at 150, 1160, 880, 650, 530, and 90 ng, respectively. The insect elicited highest attraction to a synthetic mixture of 330, 200, 1160, 940, 750, and 560 ng of pentadecane, octadecane, nonadecane, heneicosane, tricosane, and pentacosane, respectively, and hence, this combination might be used for insect pest management programme such as baited traps.

New And Neglected Morphological Features in the Taxonomy of Asian Lejeunea (Marchantiophyta)

Abstract The infrageneric classification of the large genus Lejeunea Lib. is poorly understood due to the lack of stable morphological characters characterizing supraspecific groups. Phenetic analysis of 26 morphological features of 31 Asian Lejeunea species separated two main species clusters based on the number of superior central cells at underleaf bases. The number of superior central cells had not previously been utilized in the classification of Lejeunea and appears to be new and stable morphological feature within this genus. The presence of surface wax was confirmed in L. flava (Sw.) Nees and was newly recorded in L. mimula Hürl. and L. tuberculosa Steph. We suggest that wax ornamentation may be a useful taxonomic feature at species level in Lejeunea.

Cidea Control of Lipid Storage and Secretion in Mouse and Human Sebaceous Glands

Sebaceous glands are skin appendages that secrete sebum onto hair follicles to lubricate the hair and maintain skin homeostasis. In this study, we demonstrated that Cidea is expressed at high levels in lipid-laden mature sebocytes and that Cidea deficiency led to dry hair and hair loss in aged mice. In addition, Cidea-deficient mice had markedly reduced levels of skin surface lipids, including triacylglycerides (TAGs) and wax diesters (WDEs), and these mice were defective in water repulsion and thermoregulation. Furthermore, we observed that Cidea-deficient sebocytes accumulated a large number of smaller-sized lipid droplets (LDs), whereas overexpression of Cidea in human SZ95 sebocytes resulted in increased lipid storage and the accumulation of large LDs. Importantly, Cidea was highly expressed in human sebaceous glands, and its expression levels were positively correlated with human sebum secretion. Our data revealed that Cidea is a crucial regulator of sebaceous gland lipid storage and sebum lipid secretion in mammals and humans.

The effects of Kloeckera apiculata on the cuticular waxes of navel orange fruit

Kloeckera apiculata 34-9 was selected from the rhizosphere soil for its high efficacy in controlling citrus green and blue mold. In this study, the effect of the antagonistic yeast K. apiculata on citrus cuticular wax was investigated in ripening Newhall navel orange (Citrus sinensis L. Osbeck). Our results show that K. apiculata triggers the production of cuticular waxes and surface wax morphology changes in the fruit surface. 15 K. apiculata-responsive differentially expressed genes (DEGs) were identified for wax metabolism by using the Affymetrix citrus genome GeneChip. Using GC–MS, 46 wax compounds were found in the Newhall fruit surface. On one hand, esters including docosanoic acid, 1,2,3-propanetriyl ester and 9-hexadecenoic acid, 9-octadecenyl ester were up-regulated approximately twofold in the treatment condition compared with the control; and on the other hand, the fatty acids and fatty alcohols decreased by 74.4% and 72.3%, respectively, in the treatment condition. The new wax production and increased hydrophobicity of the Newhall surface resulting from the treatment may influence spore adhesion and germination. Furthermore, the response of the fruit waxes to the K. apiculata stimulus is likely to be regulated by intra-cellular H2O2 signaling. This study demonstrated the response fruit waxes to K. apiculata in Newhall navel oranges, thus providing new clues that aid our understanding of the mechanisms of action of antagonistic yeasts in postharvest fruits.

Triterpene Biosynthesis in Plants

The triterpenes are one of the most numerous and diverse groups of plant natural products. They are complex molecules that are, for the most part, beyond the reach of chemical synthesis. Simple triterpenes are components of surface waxes and specialized membranes and may potentially act as signaling molecules, whereas complex glycosylated triterpenes (saponins) provide protection against pathogens and pests. Simple and conjugated triterpenes have a wide range of applications in the food, health, and industrial biotechnology sectors. Here, we review recent developments in the field of triterpene biosynthesis, give an overview of the genes and enzymes that have been identified to date, and discuss strategies for discovering new triterpene biosynthetic pathways.

Leaf surface wax is a source of plant methane formation under UV radiation and in the presence of oxygen

The terrestrial vegetation is a source of UV radiation-induced aerobic methane (CH4 ) release to the atmosphere. Hitherto pectin, a plant structural component, has been considered as the most likely precursor for this CH4 release. However, most of the leaf pectin is situated below the surface wax layer, and UV transmittance of the cuticle differs among plant species. In some species, the cuticle effectively absorbs and/or reflects UV radiation. Thus, pectin may not necessarily contribute substantially to the UV radiation-induced CH4 emission measured at surface level in all species. Here, we investigated the potential of the leaf surface wax itself as a source of UV radiation-induced leaf aerobic CH4 formation. Isolated leaf surface wax emitted CH4 at substantial rates in response to UV radiation. This discovery has implications for how the phenomenon should be scaled to global levels. In relation to this, we demonstrated that the UV radiation-induced CH4 emission is independent of leaf area index above unity. Further, we observed that the presence of O2 in the atmosphere was necessary for achieving the highest rates of CH4 emission. Methane formation from leaf surface wax is supposedly a two-step process initiated by a photolytic rearrangement reaction of the major component followed by an α-cleavage of the generated ketone.

Secondary spread of Zygophiala wisconsinensis on the surface of apple fruit

Although the fungus Zygophiala wisconsinensis is a prominent component of the sooty blotch and flyspeck (SBFS) disease complex of apple, few studies have characterized in situ morphological adaptations of this or other SBFS species that accompany colonization of the epicuticular wax layer of fruit. Scanning electron microscope was used to monitor stages in the formation of sclerotium-like bodies on the wax surface, as well as ramifications from these structures to form secondary sclerotium-like bodies. At a mature stage in the formation of sclerotium-like bodies, the matrix of hyphae, conidiophores, and conidia between these bodies collapsed, resulting in formation of the independent clusters of typical colonies of species in the flyspeck mycelial type. Formation of conidiophores and secondary conidia in situ were also described for the first time for any flyspeck species. Observation of conidiophores on naturally and artificially inoculated apple peels with light microscope raises the possibility that formation of secondary conidia may be an important means of spatial dispersion of Z. wisconsinensis in apple orchards and the conidia might function in secondary spread.

Comparative analysis of surface wax in mature fruits between Satsuma mandarin (Citrus unshiu) and ‘Newhall’ navel orange (Citrus sinensis) from the perspective of crystal morphology, chemical composition and key gene expression

Surface wax of mature Satsuma mandarin (Citrus unshiu) and ‘Newhall’ navel orange (Citrus sinensis) was analysed by crystal morphology, chemical composition, and gene expression levels. The epicuticular and total waxes of both citrus cultivars were mostly composed of aldehydes, alkanes, fatty acids and primary alcohols. The epicuticular wax accounted for 80% of the total wax in the Newhall fruits and was higher than that in the Satsuma fruits. Scanning electron microscopy showed that larger and more wax platelets were deposited on the surface of Newhall fruits than on the Satsuma fruits. Moreover, the expression levels of genes involved in the wax formation were consistent with the biochemical and crystal morphological analyses. These diversities of fruit wax between the two cultivars may contribute to the differences of fruit postharvest storage properties, which can provide important information for the production of synthetic wax for citrus fruits.

A novel dominant glossy mutation causes suppression of wax biosynthesis pathway and deficiency of cuticular wax in Brassica napus

BackgroundThe aerial parts of land plants are covered with cuticular waxes that limit non-stomatal water loss and gaseous exchange, and protect plants from ultraviolet radiation and pathogen attack. This is the first report on the characterization and genetic mapping of a novel dominant glossy mutant (BnaA.GL) in Brassica napus.ResultsTransmission electron microscopy revealed that the cuticle ultrastructure of GL mutant leaf and stem were altered dramatically compared with that of wide type (WT). Scanning electron microscopy corroborated the reduction of wax on the leaf and stem surface. A cuticular wax analysis of the GL mutant leaves further confirmed the drastic decrease in the total wax content, and a wax compositional analysis revealed an increase in aldehydes but a severe decrease in alkanes, ketones and secondary alcohols. These results suggested a likely blockage of the decarbonylation step in the wax biosynthesis pathway. Genetic mapping narrowed the location of the BnaA.GL gene to the end of A9 chromosome. A single-nucleotide polymorphism (SNP) chip assay in combination with bulk segregant analysis (BSA) also located SNPs in the same region. Two SNPs, two single sequence repeat (SSR) markers and one IP marker were located on the flanking region of the BnaA.GL gene at a distance of 0.6 cM. A gene homologous to ECERIFERUM1 (CER1) was located in the mapped region. A cDNA microarray chip assay revealed coordinated down regulation of genes encoding enzymes of the cuticular wax biosynthetic pathway in the glossy mutant, with BnCER1 being one of the most severely suppressed genes.ConclusionsOur results indicated that surface wax biosynthesis is broadly affected in the glossy mutant due to the suppression of the BnCER1 and other wax-related genes. These findings offer novel clues for elucidating the molecular basis of the glossy phenotype.

A STUDY OF DENTAL 3D POINTS CLOUD MEASUREMENT SYSTEM BASED ON GRATING PROJECTION

A novel non-contact dental 3D points cloud measurement system based on grating projection is proposed in this paper. The system has the key functions of calibration, phase unwrapping and conversion of two-dimensional image to the 3D point cloud and so on, and it can provide three-dimensional graphics of the dental wax with rotations and translation to observe and measure the various parts of dental wax surface. The system can be used as a useful test and analysis tool for clinical medicine teaching and researches.

Factors governing the removal of mancozeb residues from lettuces with washing solutions

Mancozeb was spiked in smooth and curly lettuces at two different concentrations (low and high), and lettuces were subjected to different washing treatments (with tap water, Amukine, hydrogen peroxide, acetic acid, and ammonium hydroxide) at varying time and temperature. The determination of residual levels was then carried out by using acetonitrile extraction and high performance liquid chromatography with diode array detection (HPLC-DAD). The study of analysis of variance among these experiments allowed identifying the main factors governing the removal of mancozeb residues from lettuces. In general, the oxidant character of the washing agent is the most important condition that affects removal of mancozeb from lettuces, being hydrogen peroxide more efficient than sodium hypochlorite. Moreover, other factors controlling mancozeb removal from lettuces are surface wax, concentration gradient, and also washing pH. The washing processing factor resulted to be a rest of 4% under the optima conditions (either Amukine solution for 10 min at 25 °C, or hydrogen peroxide solution for 5 min at water temperature of 15 °C).

Synonymy, taxonomic notes, and range extensions for several noteworthy Asian liverworts

Several noteworthy liverworts are reported from China, including Bazzania horridula Schiffn. and Riccardia tamariscina (Steph.) Schiffn. new to China, and five species new to mainland China. Cololejeunea dozyana (Sande Lac.) Schiffn. and Leptolejeunea udarii M.Dey & D.K.Singh are reported new to Thailand. Chiloscyphus yunnanensis C.Gao & Y.H.Wu, previously known only from the type locality, is proposed to be synonymous with the tropical Asian Chiloscyphus ciliolatus (Nees) J.J.Engel & R.M.Schust. SEM observations reveal that the wax-like projections on the thallus surface of Riccardia tamariscina do not belong to surface wax. Two types of oil bodies in Bazzania are illustrated. It is suggested avoiding the use of the term ‘Bazzania-type’ when oil bodies are described.

Ir-192 pellet source HDR brachytherapy using wax surface mould applicators in head and neck cancer: A single institute experience.

e17029 Background: Surface mould brachytherapy is suitable for radiation treatment of superficial lesions in head and cancer and it is the choice of radiotherapy technique. Various isotopes viz, Radium, Cs-137, Ir-192 wire, co-60, Sr-90 has been used. Earlier customized acrylic mould with hollow needle or catheters were used. With the advent of Ir-192 HDR pellet source we used tissue equivalent thermo malleable wax surface moulds. Single plane was used but in lips, pinna and ala of nose double planar sandwich technique was used with good dosimitry and cosmetic effect. BED is calculated by using LQ model. Methods: A retrospective analysis of 20 cases superficial H & N epithelial cancers treated with surface mould Brachytherapy using wax mould during 2008 to 2010 at RIMS is retrieved from the archive. HDR Ir-192 pellet source surface mould was used by positioning the flexible catheters in proper positions without distortion of geometry. The mould is made with wax plates by warming upto 70 degree Celsius in thermal water bath. The thickness of the slab is 1 cm and catheters embedded on surface and kept 1 to 1.5 cm gap and parallel to each other which can be bent or curved according to the surface contour. The fixation is reinforced with transpore /cellotapes. The dose delivered varies 500cgy 6 to 8 doses or daily 300 cgy for 5 to 7 fractions with BED calculated for LDR 2500cgy to 3000 cgy. Results: 20 cases were analysed: 8 Basal cell ca on face. SCC inner canthus 2, lips 2, pinna 1, ala nasi 2, alveolus 1, 1 hard palate, and 4 cheeks. One lip and one cheek has undergone resection with margin not free. All had disease less than 4 cm size and infiltration less than .5 cm. and clinically Node negative. At median follow up of 30 months 18 had no evidence of disease with good cosmesis and one patient with Ca. hard palate had local failure and one upper eyelid has recurrence after 9 months. Conclusions: The study though small in number indicates practicability and satisfactory results of using locally available tissue equivalent wax surface mould application therapy of HDR pellet source for very superficial T1 N0 lesions as primary mode or adjuvant radiotherapy in head and neck areas.

Alkanes in Flower Surface Waxes of Momordica cochinchinensis Influence Attraction to Aulacophora foveicollis Lucas (Coleoptera: Chrysomelidae)

Extraction, thin-layer chromatography, and gas chromatography-mass spectrophotometry analyses revealed 15 alkanes representing 97.14% of the total alkanes in the surface waxes of Momordica cochinchinensis Spreng flowers. Nonacosane was the prevailing alkane followed by hexatriacontane, nonadecane, heptacosane, and hentriacontane, accounting for 39.08%, 24.24%, 13.52%, 6.32%, and 5.12%, respectively. The alkanes from flower surface waxes followed by a synthetic mixture of alkanes mimicking alkanes of flower surface waxes elicited attraction of the female insect, Aulacophora foveicollis Lucas (Coleoptera: Chrysomelidae) between 2 and 10-μg/mL concentrations in a Y-shaped glass tube olfactometer bioassay under laboratory conditions. Synthetic nonadecane from 178.28-891.37 ng, heptacosane from 118.14-590.72 ng, and nonacosane at 784.73 ng showed attraction of the insect. A synthetic mixture of 534.82 ng nonadecane, 354.43 ng heptacosane, and 2,354.18 ng nonacosane elicited highest attraction of A. foveicollis.

Altered Lipid Composition and Enhanced Nutritional Value of Arabidopsis Leaves following Introduction of an Algal Diacylglycerol Acyltransferase 2

Enhancement of acyl-CoA-dependent triacylglycerol (TAG) synthesis in vegetative tissues is widely discussed as a potential avenue to increase the energy density of crops. Here, we report the identification and characterization of Chlamydomonas reinhardtii diacylglycerol acyltransferase type two (DGTT) enzymes and use DGTT2 to alter acyl carbon partitioning in plant vegetative tissues. This enzyme can accept a broad range of acyl-CoA substrates, allowing us to interrogate different acyl pools in transgenic plants. Expression of DGTT2 in Arabidopsis thaliana increased leaf TAG content, with some molecular species containing very-long-chain fatty acids. The acyl compositions of sphingolipids and surface waxes were altered, and cutin was decreased. The increased carbon partitioning into TAGs in the leaves of DGTT2-expressing lines had little effect on transcripts of the sphingolipid/wax/cutin pathway, suggesting that the supply of acyl groups for the assembly of these lipids is not transcriptionally adjusted. Caterpillars of the generalist herbivore Spodoptera exigua reared on transgenic plants gained more weight. Thus, the nutritional value and/or energy density of the transgenic lines was increased by ectopic expression of DGTT2 and acyl groups were diverted from different pools into TAGs, demonstrating the interconnectivity of acyl metabolism in leaves.

Long-chain alkanes: allelochemicals for host location by the insect pest, Epilachna dodecastigma (Coleoptera: Coccinellidae)

Extraction, thin-layer chromatography, and gas chromatography–mass spectrometry of leaf surface waxes of Momordica charantia L. (Cucurbitaceae) revealed that 20 n-alkanes between n-C15 and n-C36, except n-C34 and n-C35, commonly occur in young, mature, and senescent stages. Hentriacontane, hentriacontane, and hexatriacontane were the predominant compounds in young, mature, and senescent leaves, respectively. The cuticular alkanes from young, mature, and senescent leaves attracted the female insect, Epilachna dodecastigma (Wied.), at 25–400, 25–400, and 100–400 μg concentrations, respectively, whereas the mixtures of synthetic alkanes mimicking cuticular alkanes of young, mature, and senescent leaves showed attraction at 100–400, 100–400, and 200–400 μg concentrations, respectively, in Y-shaped glass tube olfactometer bioassay. The difference in insect attraction is probably due to the absence of branched-chain alkanes in the synthetic mixtures. Individual synthetic heptacosane, nonacosane, and hentriacontane at 28.19–56.90, 32.04–64.08, and 60.44–120.88 μg, respectively, elicited attraction of the insect. A synthetic blend of 4.82, 4.91, 5.71, 6.74, 56.39, 7.94, 62.42, 120.88, and 36.33 μg of nonadecane, eicosane, heneicosane, pentacosane, heptacosane, octacosane, nonacosane, hentriacontane, and tritriacontane, respectively, was most attractive to the insect.

The study on the infection of apple fruits by Botrytis cinerea Pers. after harvest

The aim of this studv was to determine the possibility to infection of apples after harvest by conidia and/or mycelium of <em>Botrytis cinerea</em> Pers. Conidia were unable to infect uninjured apple skin regardless of inoculum density and presence of nutrients. The infection of apples by conidia occurred after the surface wax had been removed by washing of apples with chloroform. Injuries of skin appeared to be a favourable entry point for conidia and mycelium of <em>B.cinerea</em>. Only the mycelium of <em>B.cinerea</em> developed on the apple but not that grown on the artificial medium (PDA) was able to directly penetration uninjured apple skin. It was observed that sometimes rotted spots develo ped arround the lenticels.

Variation of hydrocarbon constituents of epicuticular wax of leaves of Litchi chinensis Sonn.

Epicuticular wax of leaves of Litchi (Litchi chinensis Sonn.) collected all through the year and n-alkane extract was analysed by thin layer chromatography, infrared spectroscopy and gas liquid chromatography, using standard hydrocarbons. Twenty long chain hydrocarbons (n-C16 to n-C35) were identified and quantified. Distinct variation of hydrocarbon content has been observed during different time of the year. Scanning electron microscopic views of total epicuticular wax, hydrocarbon and upper surface of Litchi chinensis Sonn. leaf during the fruiting stage of the tree has also been done.

Bioinspired hierarchical superhydrophobic structures formed by n-paraffin waxes of varying chain lengths

Nature demonstrates beautiful examples of superhydrophobic surfaces, which always exhibit hierarchical roughness. We demonstrate a simple biomimetic route to the formation of hierarchical roughness on paraffin wax surfaces by the successive deposition of waxes of increasing molecular weight (Mw). By means of this procedure the lower Mw waxes grow larger crystals, forming higher micro-roughness, the subsequently deposited higher Mw waxes produce lower submicron/nano-roughness, and the overall result is roughness of a higher hierarchical order. We show that, compared to unary wax crystal surfaces, these hierarchical structures have the advantage of increased surface stability expressed by the ability to maintain smaller drops in the Cassie-state, as well as the ability to support liquids having lower surface tensions with contact angles exceeding 150°.

Environmental control on eastern broadleaf forest species’ leaf wax distributions and D/H ratios

Local climate and environment broadly affect the deuterium/hydrogen (D/H) ratios of plant materials, however the degree to which an individual plant’s leaf waxes D/H ratios are affected by these parameters remains in question. Understanding these issues is particularly important in order to reconstruct past floral transitions and changes in the paleohydrologic cycle. For this study, we sampled five co-occurring tree species, Acer rubrum, Platanus occidentalis, Juniperus virginiana, Pinus taeda, and Pinus strobus and soils at forty sites along the East Coast of the US, from Florida to Maine. Hydrogen isotopic compositions of leaf wax n-alkanes, stem and surface waters were analyzed and compared against high-resolution temperature, precipitation, relative humidity, and vapor pressure deficit data to determine environmental controls on isotopic composition.Our results demonstrate that each tree species produce a unique distribution of n-alkanes with distinct chain length pattern. Average n-alkane chain lengths recovered from soils, A. rubrum, and J. virginiana leaves show significant correlations with mean annual temperature. δD values of A. rubrum leaf n-alkanes were strongly correlated to modeled mean annual precipitation δD values and other climate parameters related to latitude (i.e. temperature, relative humidity, vapor pressure deficit), while the δD values of J. virginiana n-alkanes were not. Differences in correspondence may reflect the timing of leaf wax synthesis between the two species. Further, soil n-alkane D/H compositions were strongly correlated to modeled mean annual precipitation δD values, while the apparent hydrogen isotopic fractionation was not. These findings indicate that the isotope ratio of n-alkanes from soils in Eastern North American forests and similar ecosystems likely represents a time-averaged value that smooth out the environmental influence any one plant experiences.