Adaptive dynamics of cuticular hydrocarbons in Drosophila.

Cuticular hydrocarbons (CHCs) are hydrophobic compounds deposited on the arthropod cuticle that are of functional significance with respect to stress tolerance, social interactions and mating dynamics. We characterized CHC profiles in natural populations of Drosophila melanogaster at five levels: across a latitudinal transect in the eastern United States, as a function of developmental temperature during culture, across seasonal time in replicate years, and as a function of rapid evolution in experimental mesocosms in the field. Furthermore, we also characterized spatial and temporal changes in allele frequencies for SNPs in genes that are associated with the production and chemical profile of CHCs. Our data demonstrate a striking degree of parallelism for clinal and seasonal variation in CHCs in this taxon; CHC profiles also demonstrate significant plasticity in response to rearing temperature, and the observed patterns of plasticity parallel the spatiotemporal patterns observed in nature. We find that these congruent shifts in CHC profiles across time and space are also mirrored by predictable shifts in allele frequencies at SNPs associated with CHC chain length. Finally, we observed rapid and predictable evolution of CHC profiles in experimental mesocosms in the field. Together, these data strongly suggest that CHC profiles respond rapidly and adaptively to environmental parameters that covary with latitude and season, and that this response reflects the process of local adaptation in natural populations of D. melanogaster.

Bioassay-guided isolation of the antinociceptive compounds motiol and beta-sitosterol from Scorzonera latifolia root extract.

Scorzonera latifolia (Asteraceae) is a plant widely distributed in Central and East Anatolia. A mastic, named yaki sakizi, is prepared from the latex and roots of S. latifolia and similar species. This latex is used in Turkish folk medicine for its analgesic activity, as anthelmintic and against infertility. The aim of this study was to isolate the compounds responsible for the antinociceptive activity of S. latifolia using bioassay-guided fractionation. The methanolic extract of the S. latifolia roots was prepared and subjected to chromatographic purification. Isolated active compounds were identified by means of MS and NMR techniques. Writhing and tail-flick tests were used to determine antinociceptive activity. Motiol and beta-sitosterol were isolated as compounds with promising antinociceptive activity. It is suggested that antinociceptive activity of the plant extract is probably caused by the synergic interaction of the isolated compounds.

Transition metal complexes bearing NHC ligands substituted with secondary polyfluoroalkyl groups.

Using three different approaches, racemic 1-(perfluoroalkyl)ethylamines were synthesized from perfluoroalkyl iodides or perfluoroalkanoic acids, and further transformed to the corresponding N,N'-disubstituted ethane-1,2-diimines and ethane-1,2-diamines as mixtures of diastereoisomers. Their cyclization afforded imidazolium or dihydroimidazolium salts, which led to silver or palladium complexes bearing NHC ligands substituted with secondary polyfluoroalkyl groups. The palladium complexes bearing a throwaway 3-chloropyridine ligand proved to be moderately active in the model Suzuki-Miyaura coupling.

Comparison of methods employing gas chromatography retention data to determine vapour pressures at 298 K.

Validity of five models suggested for expressing the relationship between vapour pressures and GC retention times measured on a non-polar capillary column were tested on a common set of compounds [five homologous series of the type H-(CH2)n-Y, where Y denotes Cl, Br, CHO, OCOCH3 and COOCH3, and n varies from 6 to 14]. Standard methods of statistical analysis, as well as vapour pressure values obtained independently from direct vapour pressure measurements were used as validity criteria. For the 40-compound data set examined, the methods provided vapour pressures agreeing within 9.2-24.7% (average absolute percent error) with direct experimental data.

Tomentomimulol and mimulone B: two new C-geranylated flavonoids from Paulownia tomentosa fruits.

Two new discovered C-geranylated flavonoids tomentomimulol (1) and mimulone B (2) were isolated from the methanol extract of Paulownia tomentosa (Thunb). Steud. (Paulowniaceae) fruits by exhaustive chromatographic separation together with one known compound tanariflavanone D (3). The identification of compounds and structure elucidation was carried out using 1D and 2D NMR experiments, as well as mass spectroscopy, ultra-violet, infra red and CD experiments.

A new triterpene from Scorzonera latifolia (Fisch. and Mey.) DC.

A novel triterpene 1 (3-ß-hydroxy-fern-7-en-6-one-acetate) together with four known compounds, urs-12-en-11-one-3-acetyl (2), 3-ß-hydroxy-fern-8-en-7-one-acetate (3), olean-12-en-11-one-3-acetyl (4) and leucodin (5) were obtained from the S. latifolia roots. All compounds were isolated from the n-hexane extract of S. latifolia roots using several chromatographic techniques. The structure of the isolated compounds was elucidated on the basis of (1)H-NMR, (13)C-NMR and 2D NMR data (HMBC, HMQC, COSY, TOCSY, NOESY, DEPT) as well as GC EITOF-HRMS.

Explosive backpacks in old termite workers.

By nature, defensive behavior is risky. In social insects, such behavior is more likely to occur in individuals whose potential for other tasks is diminished. We show that workers of the termite Neocapritermes taracua develop an exceptional two-component suicidal apparatus consisting of copper-containing protein crystals, stored in external pouches, and internal salivary glands. During aggressive encounters, their bodies rupture, and the crystals react with the salivary gland secretion to produce a toxic droplet. Both the amount of defensive substances and the readiness to explode increase with workers' age, as their food-collecting ability declines.

Electrochemical methods for monitoring of environmental carcinogens.

The use of modern electroanalytical techniques, namely differential pulse polarography, differential pulse voltammetry on hanging mercury drop electrode or carbon paste electrode, adsorptive stripping voltammetry and high performance liquid chromatography with electrochemical detection for the determination of trace amounts of carcinogenic N-nitroso compounds, azo compounds, heterocyclic compounds, nitrated polycyclic aromatic hydrocarbons and aromatic and heterocyclic amines is discussed. Scope and limitations of these methods are described and some practical applications based on their combination with liquid-liquid or solid phase extraction are given.

Chemical degradation of wastes of antineoplastic agents amsacrine, azathioprine, asparaginase and thiotepa.

As a part of a program devoted to the destruction of antineoplastic agents, three chemical methods readily available in the hospital environment, viz. oxidation with sodium hypochlorite (NaClO, 5%), hydrogen peroxide (H2O2, 30%), and Fenton reagent (FeCl2.2H2O; 0.3 g in 10 ml H2O2, 30%), were tested for the degradation of four anticancer drugs: Amsacrine, Azathioprine, Asparaginase and Thiotepa. The efficiency of the degradation was monitored by high-performance liquid chromatography. The mutagenicity of the degradation residues were tested by Ames test using tester strains Salmonella typhimurium TA 97a, TA 98, TA 100 and TA 102 with and without an exogenous metabolic activation system. Using sodium hypochlorite, 98.5% of Amsacrine, 99.0% of Azathioprine, 99.5% of Asparaginase and 98.7% of Thiotepa were destroyed after 1 hr. The hydrogen peroxide treatment destroyed 99% of Asparaginase and 98.7% of Thiotepa in 1 hr. However, this procedure was not efficient for the treatment of Amsacrine (28% after 16 hr) and of Azathioprine (53% degradation in 4 hr). The action of Fenton reagent resulted in the destruction of 98% of Amsacrine, and 99.5% of Azathioprine, 98.5% of Asparaginase and 98.7% of Thiotepa in 1 hr. In all cases where a high degree of degradation was achieved, the residues obtained weee non mutagenic.