Monika Paszkiewicz

Cuticular lipids of insects as potential biofungicides: methods of lipid composition analysis

The main function of cuticular lipids in insects is the restriction of water transpiration through the surface. Lipids are involved in various types of chemical communication between species and reduce the penetration of insecticides, chemicals, and toxins and they also provide protection from attack by microorganisms, parasitic insects, and predators. Hydrocarbons, which include straight-chain saturated, unsaturated, and methyl-branched hydrocarbons, predominate in the cuticular lipids of most insect species; fatty acids, alcohols, esters, ketones, aldehydes, as well as trace amounts of epoxides, ethers, oxoaldehydes, diols, and triacylglycerols have also been identified. Analyses of cuticular lipids are chemically relatively straightforward, and methods for their extraction should be simple. Classically, extraction has relied mainly on application of apolar solvents to the entire insect body. Recently, several alternative methods have been employed to overcome some of the shortcomings of solvent extraction. These include the use of solid-phase microextraction (SPME) fibers to extract hydrocarbons from the headspace of heated samples, SPME to sample live individuals, and a less expensive method (utilized for social wasps), which consists of the collection of cuticular lipids by means of small pieces of cotton rubbed on the body of the insect. Both classical and recently developed extraction methods are reviewed in this work. The separation and analysis of the insect cuticular lipids were performed by column chromatography, thin-layer chromatography (TLC), high performance liquid chromatography with a laser light scattering detector (HPLC-LLSD), gas chromatography (GC), and GC–mass spectrometry (MS). The strategy of lipid analysis with the use of chromatographic techniques was as follows: extraction of analytes from biological material, lipid class separation by TLC, column chromatography, HPLC-LLSD, derivatization, and final determination by GC, GC-MS, matrix-assisted laser desorption/ionization (MALDI) time-of-flight (TOF) MS, and liquid chromatography–mass spectrometry (LC-MS).

Application of chitin and chitosan as elicitors of coumarins and furoquinolone alkaloids in Ruta graveolens L. (common rue)

Common rue (Ruta gra veolens L.) accumulates various types of secondary metabolites, such as coumarins furanocoumarins, acridone and quinolone alkaloids and flavonoids. Elicitation is a tool extensively used for enhancing secondary‐metabolite yields. Chitin and chitosan are examples of elicitors inducing phytoalexin accumulation in plant tissue. The present paper describes the application of chitin and chitosan as potential elicitors of secondary‐metabolite accumulation in R. graveolens shoots cultivated in vitro . The simple coumarins, linear furanocoumarins, dihydrofuranocoumarins and furoquinolone alkaloids biosynthesized in the presence of chitin and chitosan were isolated, separated and identified. There was a significant increase in the growth rate of R. graveolens shoots in the presence of either chitin or chitosan. Moreover, the results of the elicitation of coumarins and alkaloids accumulated by R. graveolens shoots in the presence of chitin and chitosan show that both compounds induced a significant increase in the concentrations of nearly all the metabolites. Adding 0.01% chitin caused the increase in the quantity (μg/g dry weight) of coumarins (pinnarin up to 116.7, rutacultin up to 287.0, bergapten up to 904.3, isopimpinelin up to 490.0, psoralen up to 522.2, xanhotoxin up to 1531.5 and rutamarin up to 133.7). The higher concentration of chitosan (0.1%) induced production of simple coumarins (pinnarin up to 116.7 and rutacultin up to 287.0), furanocoumarins (bergapten up to 904.3, isopimpinelin up to 490.0, psoralen up to 522.2, xanhotoxin up to 1531.5) and dihydrofuranocoumarins (chalepin up to 18 and rutamarin up to 133.7). Such a dramatic increase in the production of nearly all metabolites suggests that these compounds may be participating in the natural resistance mechanisms of R. graveolens . The application of chitin‐ and chitosan‐containing media may be considered a promising prospect in the biotechnological production of xanthotoxin, isopimpinelin, psoralen, chalepin or methoxylated dictamnine derivatives.

The composition of the free fatty acids from Dendrolimus pini exuviae

The pine moth Dendrolimus pini effectively resists many insecticides, but it can be controlled by the use of bioinsecticides such as entomopathogenic fungi. In the use of microbial agents for the biocontrol of D. pini, it is important to identify the cuticular lipids of this pest if we are to understand the factors responsible for the preferential adhesion or selective repulsion of entomopathogenic fungi that are potentially useful in biocontrol. In this work the qualitative and quantitative analyses of free fatty acids in two exuviae extracts (petroleum ether and dichloromethane) and two developmental stages (larval-larval and larval-pupal molts) were studied. The free fatty acid composition of the epicuticular lipids from exuviae of D. pini was characterized chemically using gas chromatography (GC) and gas chromatography-electron impact mass spectrometry (GC-MS). Structural analyses of the dichloromethane extracts from larval-larval exuviae (LLE) and larval-pupal exuviae (LPE) revealed that the carbon numbers for the major acid moieties ranged from C(8:0) to C(34:0). Only C(23:0) was not identified in the LPE extract. The relative contents of fatty acids in the extracts varied from trace amounts to 34%. The fatty acids extracted by dichloromethane were essentially the same as those in the petroleum ether extract. We also identified dehydroabietic acid in the exuviae of D. pini. The respective quantities of dehydroabietic acid obtained from D. pini LLE and LPE were 1763+/-103 microg/g exuviae and 11521+/-1198 microg/g of exuviae.

Cuticular and internal n-alkane composition of Lucilia sericata larvae, pupae, male and female imagines: application of HPLC-LLSD and GC/MS-SIM

The composition of cuticular and internal n-alkanes in Lucilia sericata larvae, pupae, and male and female imagines were studied. The cuticular and internal lipid extracts were separated by HPLC-LLSD, after which the hydrocarbon fraction was identified by GC/MS in selected ion monitoring (SIM) and total ion current (TIC) modes. The cuticular lipids of the larvae contained seven n-alkanes from C23 to C31. The major n-alkane in L. sericata larvae was C29 (42.1%). The total cuticular n-alkane content in the cuticular lipids was 31.46 μg g-1 of the insect body. The internal lipids of L. sericata larvae contained five n-alkanes ranged from C25 to C31. The most abundant compound was C27 (61.71 μg g-1 of the insect body). Eighteen n-alkanes from C14 to C31 were identified in the cuticular lipids of the pupae. The most abundant n-alkanes ranged from C25 to C31; those with odd-numbered carbon chains were particularly abundant, the major one being C29:0 (59.5%). Traces of eight cuticular n-alkanes were present. The internal lipids of L. sericata pupae contained five n-alkanes, ranging from C25 to C31. The cuticular lipids of female imagines contained 17 n-alkanes from C12 to C30. Among the cuticular n-alkanes of females, C27 (47.5%) was the most abundant compound. Four n-alkanes, with only odd-numbered carbon chains, were identified in the internal lipids of females. The lipids from both sexes of L. sericata had similar n-alkane profiles. The cuticular lipids of adult males contained 16 n-alkanes ranging from C13 to C31. C27 (47.9%) was the most abundant cuticular n-alkanes in males. The same n-alkanes only with odd-numbered carbon chains and in smaller quantities of C27 (0.1%) were also identified in the internal lipids of males. The highest amounts of total cuticular n-alkanes were detected in males and females of L. sericata (330.4 and 158.93 μg g-1 of the insect body, respectively). The quantities of total cuticular alcohols in larvae and pupae were smaller (31.46 μg g-1 and 42.08 μg g-1, respectively). The internal n-alkane contents of larvae, pupae, and male and female imagines were significantly higher than the cuticular n-alkane contents (153.53, 99.60, 360.06 and 838.76 μg g-1 of the insect body, respectively).

Antimicrobial activity of alcohols from Musca domestica

SUMMARY Information on the stimulatory and inhibitory effects of cuticular alcohols on growth and virulence of insecticidal fungi is unavailable. Therefore, we set out to describe the content of cuticular and internal alcohols in the body of housefly larvae, pupae, males and females. The total cuticular alcohols in larvae, males and females of Musca domestica were detected in comparable amounts (4.59, 3.95 and 4.03 μg g−1 insect body, respectively), but occurred in smaller quantities in pupae (2.16 μg g−1). The major free alcohol in M. domestica larvae was C12:0 (70.4%). Internal alcohols of M. domestica larvae were not found. Among cuticular pupae alcohols, C12:0 (31.0%) was the most abundant. In the internal lipids of pupae, only five alcohols were identified in trace amounts. The most abundant alcohol in males was C24:0 (57.5%). The percentage content of cuticular C24:0 in males and females (57.5 and 36.5%, respectively) was significantly higher than that of cuticular lipids in larvae and pupae (0.9 and 5.6%, respectively). Only two alcohols were present in the internal lipids of males in trace amounts (C18:0 and C20:0). The most abundant cuticular alcohols in females were C24:0 (36.5%) and C12:0 (26.8%); only two alcohols (C18:0 and C20:0) were detected in comparable amounts in internal lipids (3.61±0.32 and 5.01±0.42 μg g−1, respectively). For isolated alcohols, antimicrobial activity against 10 reference strains of bacteria and fungi was determined. Individual alcohols showed approximately equal activity against fungal strains. C14:0 was effective against gram-positive bacteria, whereas gram-negative bacteria were resistant to all tested alcohols. Mixtures of alcohols found in cuticular lipids of larvae, pupae, males and females of M. domestica generally presented higher antimicrobial activity than individual alcohols. In contrast, crude extracts containing both cuticular and internal lipids showed no antifungal activity against the entomopathogenic fungus Conidiobolus coronatus, which efficiently kills adult house flies.

1-Methyl-3-octylimidazolium chloride - sorption and primary biodegradation analysis in activated sewage sludge.

Ionic liquids (ILs) are known to be non-volatile and thus to have low potential for atmospheric contamination or intoxication of humans by inhalation. However ILs have the potential to contaminate soil and water as they might be water soluble and can be sorbed onto solids. The investigation of possible natural ways of reducing the concentration of ILs in the environment is of high importance, especially because the requirement for biodegradable chemicals increases, together with pressure for reduction of incineration and landfill waste. It was found that the upper concentration threshold for primary biodegradation of 1-methyl-3-octylimidazolium chloride is 0.2 mM. At higher concentrations the dehydrogenase activity of the cells dropped markedly, indicating that the IL inhibits cell activity. This concentration is in good agreement with the minimal inhibitory concentration of the same compound found for a series of bacteria and fungi by this research group. The sorption of 1-methyl-3-octylimidazolium chloride was found to be significant, and the sorption coefficient was determined to be 98.2 L kg-1.

Relevant parameters for assessing the environmental impact of some pyridinium, ammonium and pyrrolidinium based ionic liquids

Several physico-chemical properties relevant to determine the environmental impact of ionic liquids - aqueous solubility, octanol/water partition coefficient, chromatographically derived lipophilicity and infinite dilution diffusion coefficients in water - were measured in ionic liquids based on pyridinium, ammonium and pyrrolidinium cations with bis(trifluoromethylsulfonyl)imide anions. The influence of the presence of hydroxyl or ester groups in the physico-chemical properties of these liquids was checked. It appeared that the presence of functional oxygenated moieties reduces the lipophilicity of ionic liquids and so decreases the risk of bioaccumulation in environment.

Optimization of a procedure for the simultaneous extraction of polycyclic aromatic hydrocarbons and metal ions by functionalized and non-functionalized carbon nanotubes as effective sorbents

In this publication, a new dispersive solid-phase extraction (dSPE) method combined with gas chromatography-mass spectrometry and atomic absorption spectrometry was developed for the simultaneous determination of 9 PAHs and chromium, cadmium, and lead ions in water samples. For this purpose, non-modified multi-walled carbon nanotubes (MWCNTs) and modified -MWCNTs (OH-MWCNTs and COOH-MWCNTs) were used as sorbents. Parameters affecting the extraction, such as the amount of sorbent, the pH of the sample, the composition and volume of eluents and the extraction time were optimized. Sequential elution was applied using 6mL of dichloromethane for the elution of PAHs and 5mL of 3M HNO3 for cadmium, lead, and chromium. The optimal values of other parameters were as follows: 50mg of sorbent per 250mL of water sample, pH in a range from 6 to 7 and 30min of contact time between the sorbent and analytes. The results demonstrated the high extraction capability of modified MWCNTs with recoveries between 80 and 101% for cadmium, chromium, and lead ions and between 83 and 92% for PAHs. Finally, the optimized method was validated, and the matrix effects were determined.

Interaction of Novel Ionic Liquids with Soils

With the constant development of new ionic liquids, the understanding of the chemical fate of these compounds also needs to be updated. To this effect, the interaction of a number of novel ionic liquids with soils was determined. Therefore, three novel headgroups (ammonium, phosphonium, or pyrrolidinium) with single or quaternary substitution were tested on a variety of soils with high-to-low organic matter content and high-to-low cation exchange capacity, thereby trying to capture the full range of possible soil interactions. It was found that the ionic liquids with single butyl alkyl chain interacted more strongly with the soils (especially with a higher cation exchange capacity), at lower concentrations, than the quad-substituted ionic liquids. However, the quad-substituted ionic liquids interacted more strongly at higher concentrations, due to the double-layer formation, and induced stronger dipole interaction with previously sorbed molecules.

Carbon Nanotubes Application in the Extraction Techniques of Pesticides: A Review

ABSTRACT Carbon nanotubes (CNTs) are currently one of the most promising groups of materials with some interesting properties, such as lightness, rigidity, high surface area, high mechanical strength in tension, good thermal conductivity or resistance to mechanical damage. These unique properties make CNTs a competitive alternative to conventional sorbents used in analytical chemistry, especially in extraction techniques. The amount of work that discusses the usefulness of CNTs as a sorbent in a variety of extraction techniques has increased significantly in recent years. In this review article, the most important feature and different applications of solid-phase extraction (SPE), including, classical SPE and dispersive SPE using CNTs for pesticides isolation from different matrices, are summarized. Because of high number of articles concerning the applicability of carbon materials to extraction of pesticides, the main aim of proposed publication is to provide updated review of the latest uses of CNTs by covering the period 2006–2015. Moreover, in this review, the recent papers and this one, which are covered in previous reviews, will be addressed and particular attention has been paid on the division of publications in terms of classes of pesticides, in order to systematize the available literature reports.