Detection of 3,4-methylenedioxymethamphetamine (MDMA, ecstasy) by displacement of antibodies

A molecular layer with low non-specific binding enabling determination of low concentrations of 3,4-methylenedioxymethamphetamine (MDMA) by the displacement of antibodies has been developed. Antibody Fab′-fragments at various concentrations have been site-directly immobilised on gold and intercalated with a hydrophilic non-ionic polymer that reduces non-specific binding. Bovine serum albumin conjugated with MDMA and various concentrations of anti-MDMA antibodies were bound to the layer. The amount of conjugates and antibodies bound was dependent on the amount of Fab′-fragments in the layer. Antibodies were also bound to the conjugates physisorbed directly onto the gold surface and in mixtures with the polymer or with a lipoamide. A high displacement of antibodies was observed by surface plasmon resonance (SPR) on interaction of MDMA with the different layers in buffer solution. No displacement could, however, be observed in saliva with the pure conjugate layer because of a high non-specific binding of proteins. When the conjugates were coupled to the surface through the antibody Fab-fragment/polymer layer, MDMA concentrations as low as 0.02 ng mL⁻¹ (0.14 nM) could easily be detected in buffer. In diluted saliva the lowest limit of detection was 0.4 ng mL⁻¹ enabling determination of drugs from saliva with a cut-off concentration of 2 ng mL⁻¹. The molecular layer of antibody Fab′-fragments and polymer thus shows great potential for binding conjugates and antibodies that can be displaced on the interaction with very low concentrations of small-sized molecules. A low non-specific binding is guaranteed by the presence of the hydrophilic polymer.     

Pyrrolizidine alkaloid content in crude and processed borage oil from different processing stages

The pyrrolizidine alkaloid content of crude borage oil and borage oil from different processing stages was determined by GC-MS. The results showed that no pyrrolizidine alkaloids were present above a detection limit of 20 ppb. The reduction factors for pyrrolizidine alkaloids at various stages in the oil refining process were determined by means of spiking experiments using the commercially available pyrrolizidine alkaloid crotaline. It was shown that the pyrrolizidine content in crude borage oil was reduced overall by a factor of about 30,000 in the refining process.     

Authentication of marine oils using 13C NMR spectroscopy

NMR spectroscopy has been particularly valuable in the study of lipids, since it provides qualititative and quantitative information on chemically diverse compounds in a non‐destructive and non‐selective fashion. NMR gives a fingerprint of the sample analyzed and may be used as a rapid profiling technique. Combined with chemometrics and databases with relevant authentic samples, ¹³C NMR is a powerful tool for authentication of marine oils.     

Does Indole Alkaloid Gramine Confer Resistance in Barley to Aphid Rhopalosiphum Padi?

Accessions of cultivated barley (Hordeum vulgare ssp. vulgare) and its wild progenitor Hordeum vulgare ssp. spontaneum (H. ssp. spont.) were screened for gramine content at the seedling stage. H. ssp. spont. generally had higher gramine concentration compared with cultivated spring barley. Thus gramine concentrations might be raised in modern barley through crossings with selected H. ssp. spont. accessions and repeated back-crossings (BC) of selected offspring to cultivated barley. In the present study, the barley cultivar Lina was used as the recurrent parent. Lina was exceptional among the two-rowed barleys in that it contained moderate levels of gramine, whereas most of the others were very low in gramine. Chromosome-doubled haploid lines (DHs) from the first generation (F₁) had a skewed distribution towards higher gramine concentrations and so had the first back-cross generation (BC₁F₁-DHs). A hairy plant surface, another character proposed to confer resistance to aphids, was also found among some of the plants in the breeding material. BC₁F₁-DHs with a high proportion of the Lina genome, as determined in an analysis of PCR-based molecular markers, in addition to high gramine concentrations and hairy plant bases in two cases were tested for resistance to the barley pest Rhopalosiphum padi. However, based on aphid performance and preference tests, there were no indications that either high gramine concentrations or hairiness conferred resistance to R. padi when compared with Lina and a variety very low in gramine (Golf). The pattern was the same when the F₁ generation was evaluated in aphid performance tests along with Lina, Golf, and the six H. ssp. spont. parents. Aphid weight was consistently low on only one of the six H. ssp. spont. parents. Since previous reports of a positive relationship between gramine concentrations and resistance to R. padi were based on studies in Chile and Japan, a Chilean R. padi population was compared with three Swedish populations, but the responses of all four populations were similar.     

Occurrence and Correlations of Monoterpene Hydrocarbon Enantiomers in Pinus sylvestris and Picea abies

The relative amounts and enantiomeric compositions of monoterpene hydrocarbons in branch and trunk xylem, in needles, and in resin from apical buds in 18 Pinus sylvestris trees have been determined and compared with the terpene content in branch xylem and needles of Picea abies. Besides the high amount of (+)-3-carene, an excess of (+)--pinene has been found in P. sylvestris, whereas in P. abies (–)--pinene dominates over (+)--pinene. In P. sylvestris, clear positive correlations were found between (+)--pinene and (+)-camphene in the four tissues analyzed. Good positive correlations were also observed between (–)--pinene and (–)-camphene in the two types of xylem, between (+)--pinene and (+)--pinene in the resin, and between tricyclene and (–)-camphene in resin and needles. In P. abies, positive correlations were found between (+)--pinene and (+)-camphene in the branch xylem and between tricyclene and (–)-camphene as well as between (–)--pinene and (–)-camphene in the needles. Complex relationships between (–)--pinene and (–)--pinene were found both in the P. abies and in the P. sylvestris tissues. The importance of the enantiomeric composition of -pinene for the host selection of Ips typographus, Tomicus piniperda, and Hylobius abietis is discussed.     

Selective N2O Removal from the Process Gas of Nitric Acid Plants Over Ceramic 12CaO · 7Al2O3 Catalyst

Catalytic high temperature decomposition (secondary abatement) of nitrous oxide over calcium aluminate 12CaO · 7Al₂O₃ (mayenite) was studied in the model laboratory tests (TPSR) and pilot units (steady-state) using the real feed. X-ray diffraction (XRD), scanning electron microscopy (SEM), N₂-sorption (BET), electron paramagnetic resonance (EPR) and Raman spectroscopies were used to characterize the synthesized material. The catalyst exhibited high efficiency and selectivity in N₂O removal, reaching practically 100% conversion at 1150 K without appreciable total losses of NO _x . Owing to its high thermal stability and resistivity to sintering and low cost of production raw materials, mayenite was found to be a promising catalyst for economically appealing secondary abatement of nitrous oxide in nitric acid plants.     

Direct aerobic oxidation of primary alcohols to methyl esters catalyzed by a heterogeneous gold catalyst

Methyl esters can be produced in high yields by oxiding methanolic solutions of primary alcohols with dioxygen over a heterogeneous gold catalyst. The versatility of this new methodology is demonstrated by the fact that alkylic, benzylic and allylic alcohols, as well as alcohols containing an amine functionality are oxidized in good to excellent yields.     

Comparative Neuropharmacology and Pharmacokinetics of Methamphetamine and Its Thiophene Analog Methiopropamine in Rodents

Methiopropamine is a novel psychoactive substance (NPS) that is associated with several cases of clinical toxicity, yet little information is available regarding its neuropharmacological properties. Here, we employed in vitro and in vivo methods to compare the pharmacokinetics and neurobiological effects of methiopropamine and its structural analog methamphetamine. Methiopropamine was rapidly distributed to the blood and brain after injection in C57BL/6 mice, with a pharmacokinetic profile similar to that of methamphetamine. Methiopropamine induced psychomotor activity, but higher doses were needed (E_max 12.5 mg/kg; i.p.) compared to methamphetamine (E_max 3.75 mg/kg; i.p.). A steep increase in locomotor activity was seen after a modest increase in the methiopropamine dose from 10 to 12.5 mg/kg, suggesting that a small increase in dosage may engender unexpectedly strong effects and heighten the risk of unintended overdose in NPS users. In vitro studies revealed that methiopropamine mediates its effects through inhibition of norepinephrine and dopamine uptake into presynaptic nerve terminals (IC₅₀ = 0.47 and 0.74 µM, respectively), while the plasmalemmal serotonin uptake and vesicular uptake are affected only at high concentrations (IC₅₀ > 25 µM). In summary, methiopropamine closely resembles methamphetamine with regard to its pharmacokinetics, pharmacodynamic effects and mechanism of action, with a potency that is approximately five times lower than that of methamphetamine.     

Superchilled,chilled and frozen storage of Atlantic mackerel (Scomber scombrus) fillets – changes in texture,drip loss,protein solubility and oxidation

Changes in quality characteristics in relation to protease activity and protein oxidation in chilled, superchilled and frozen mackerel fillets during storage were studied. The solubility of sarcoplasmic proteins was quite stable in mackerel samples for all storage experiments, whereas the solubility of myofibrillar proteins decreased in both superchilled and frozen samples. A significant correlation (r = 0.983, P < 0.05) between the increased activity of cathepsin B+L in chilled fillets and softening of the fish flesh during storage was revealed. Contrary with chilled samples, the texture of superchilled mackerel fillets became tougher along the storage period, which can be explained by a higher rate of myofibrillar oxidation (r = 0.940, P < 0.05). The hardness and drip loss decreased slightly at the end of frozen storage. Superchilling preserved the quality of mackerel fillets with the least side effects in relation to protein solubility, drip loss and softening of the fish tissue as compared to chilled and frozen storage.