Artificially applied plant volatile organic compounds modify the behavior of a pest with no adverse effect on its natural enemies in the field

The use of volatile organic compounds (VOCs) derived from plants to manipulate insect pest behavior can be applied in an integrated pest management strategy (IPM) using a combination of attractive and repulsive stimuli. The “push–pull” strategy was developed on this idea in order to disturb and modify the distribution and abundance of pests to protect crops and reduce the use of agrochemicals. This field experiment investigates, in a “push–pull” context using broccoli as a target crop and Chinese cabbage as a pull component, the stimulo-deterrent effect of five synthetic VOCs (dimethyl disulfide, linalool, geraniol, eucalyptol and citronellol) on the oviposition of the cabbage root fly Delia radicum. With the exception of linalool, all compounds tested had a significant effect in the field and eucalyptol showed the most promising results, reducing oviposition on broccoli by 45 %. Moreover, eucalyptol was the only VOC able to reduce the final infestation of D. radicum, i.e., the number of pupae. The other VOCs reduced oviposition by 20–30 %. No adverse effect of the treatments was found on major parasitoids (Trybliographa rapae and Aleochara bipustulata) and potential predators of D. radicum. This study highlights the potential of VOCs as deterrent stimuli against agricultural pests in the field.     

Equine postanaesthetic myositis: Thromboxanes,prostacyclin and prostaglandin E2 production

Arachidonic acid cyclooxygenase metabolites, thromboxane B₂ (TXB₂), prostaglandin E₂ (PGE₂) and 6-keto-prostaglandin F₁ (6-keto-PGF₁) were measured in horses where anaesthesia was maintained with halothane. Two horses suffering from postanaesthetic myositis were compared with four normal horses. TXB₂ and PGE₂ levels were higher in mixed venous blood drawn from the myopathic horses. An increase of TXB₂ and PGE₂ levels appeared when myopathic horses were rolled into dorsal recumbency after a prolonged period of lateral recumbency. One hour after the end of anaesthesia, TXB₂ had continued to increase whereas PGE₂ decreased. By measurements on blood samples drawn from the brachial vein, we have shown that the rising level of TXB₂ in mixed venous blood is mainly due to the increase of TXB₂ in blood draining the dependent leg. The origin of the rise in PGE₂ is not demonstrated in this study. 6-keto-PGF₁ did not change during anaesthesia. An explanation of this imbalance between TXB₂ and 6-keto-PGF₁ production is considered.     

Fermentation enhances the biological activity of Allium cepa bulb extracts

In this study, we compared the analytical fingerprint and bioactivity of three onion extracts, including an aqueous, a methanol, and a fermented aqueous extract. The extracts were characterized by HPLC-DAD, LC-MS, and GC-MS analyses. The antibacterial, antigenotoxic, and antiproliferative activity of these extracts was assessed by means of agar disk diffusion, bacterial growth kinetics, a comet assay, cell cycle distribution analysis, and cell viability testing. Both the aqueous and methanolic extracts showed a typical flavonol-fingerprint as assessed by HPLC measurements and showed little to no bioactivity. The fermented aqueous extract, which lacks the usual onion flavonoid profile, was found to be the most active in all of the assays. This finding indicates that metabolites of onion compounds, generated by lactic acid fermentation, may be more active than their precursor substances.     

Purification of myeloperoxidase from equine polymorphonuclear leucocytes.

Increases of plasma concentrations of neutrophil myeloperoxidase (MPO) can be used as markers of polymorphonuclear leucocytes (PMN) activation in pathological situations (sepsis, acute lung injury, acute inflammation). To develop an assay for measurement of plasma MPO in horses during the above-mentioned infectious and inflammatory conditions, MPO was purified from equine PMN isolated from blood anticoagulated with citrate. PMN were extracted in a saline milieu (0.2 M Na acetate, 1 M NaCl, pH 4.7) to eliminate most of cellular proteins. Pellets were then extracted in the same buffer containing cationic detergent (1% cetyltrimethyl ammonium bromide). The supernatant was further purified by ion exchange chromatography (Hiload S Sepharose HP column 0.5 x 26 cm, equilibrated with 25 mM Na acetate, 0.2 M NaCl, pH 4.7) with a NaCl gradient (until 1 M). Most of the peroxidase activity of MPO (spectrophotometrically measured by the oxidation of orthodianisidine by hydrogen peroxide) was eluted at 0.65 M NaCl. MPO was further purified by gel filtration chromatography (Sephacryl S 200 column 2.6 x 42 cm with 25 mM Na acetate, 0.2 M NaCl, pH 4.7). MPO (specific activity: 74.3 U/mg) was obtained with a yield of 30% from the detergent extraction supernatant. Electrophoresis (non-reducing conditions) showed 3 bands identified, by comparison with human MPO, (i) the mature tetrameric enzyme (150 kDa) with 2 light and 2 heavy subunits, (ii) the precursor form (88 kDa) and (iii) a form of the heavy subunit without the prosthetic heme group (40 kDa). The mature enzyme and its precursor were glycosylated and possessed peroxidase activity. Equine MPO showed strong similarities with human and bovine MPO, with an absorption peak at 430 nm (Soret peak) characteristic of ferrimyeloperoxidase. Enzymatic activity was pH dependent (optimal value at pH 5.5).     

Approche directe pour la mise en évidence des phénomènes radicalaires lors de myopathie postanesthésique équine: étude préliminaire.

This preliminary study demonstrated the existence of a free radical generation during an experimental postischemic muscular reperfusion in a halothane anesthetized horse. The authors used alpha-phényl-N-tert-butylnitrone as a spin trap agent and the electronic paramagnetic resonance method to observe in vivo a free radical generation.     

Use of major- and trace-element correlations to assess metal migration in sandy Luvisols irrigated with wastewater

Soils irrigated with raw wastewater for many years accumulate trace metals, especially in the surface horizon. We do not know, however, to what extent the metals migrate down the profile and whether they accumulate in deeper horizons. We assessed the migration of trace metals in the suburbs of Paris where market gardens had been irrigated with wastewater for more than 100 years. Within a soil series, we compared metals in the polluted soils with those of a reference soil of the same kind. We sampled by horizons three representative Luvisol profiles in the irrigated area and a fourth profile selected as a reference just outside the irrigated area. Large quantities of Zn, Pb, Cd and Cu appeared to have accumulated in the topsoil, at the base of which concentrations diminished markedly. There appeared to be appreciable migration into the subsoil only at the most intensely irrigated site. By relating the total trace metal contents to the total iron contents we could detect anomalous values and identify migration into the subsurface horizons more sensitively. This approach was tested first with the endogenous metal Cr, then with metal pollutants. We showed that Zn, Pb, Cd and Cu migrated downwards in all three irrigated soils.     

Factors affecting the three-dimensional distribution of exogenous zinc in a sandy Luvisol subjected to intensive irrigation with raw wastewaters

Massive volumes of raw wastewater have been spread on sandy Luvisols in the Paris region since 1899, causing major soil contamination with metallic trace elements (MTE). To identify the factors influencing the vertical and horizontal redistribution of MTE at the plot scale, a study was carried out of the three‐dimensional distribution of zinc. The background and exogenous fractions of zinc in the contaminated soil were discriminated using correlations between zinc and iron defined from unpolluted soils of the area. At the surface, the spatial distribution of zinc is determined by the geometry of the irrigation system and the terrain topography. The highest concentrations are observed near the irrigation outlets and in areas of very slight slope. The exogenous zinc has migrated down to the base of the studied solums (1 m depth), and its subsurface distribution depends upon the physico‐chemical properties of the horizons. In the E horizon, the trapping of exogenous zinc is governed by the number of available reactive sites, whereas in the Bt horizon it is a function of the vertical and lateral behaviour of the drainage. Moreover, lateral transfer of exogenous zinc occurs in the C horizon. In the case of soil contaminated with raw wastewater, the organization of water flow on the surface and in the subsurface is a determining factor in the redistribution of zinc within a plot.     

Identification and quantification of geosmin, an earthy odorant contaminating wines

Musty, earthy odors are highly detrimental to the aromatic quality of wines. A characteristic aroma of freshly tilled earth, damp cellar was studied in some red and white wines of different origins. The extraction and purification of the wines marked by this odor have shown after analysis by gas chromatography-olfactometry a unique strong odorous zone having the same odor as the one perceived at tasting. The compound responsible for this odorous zone was identified by gas chromatography-mass spectrometry as geosmin (trans-1,10-dimethyl-trans-9-decalol), which possesses a distinctive earthy odor. Geosmin may be present in wines at levels higher than the racemic geosmin olfactory perception threshold, thus suggesting its contribution to their off-aroma. Moreover, the presence of this compound in juice taken from freshly crushed grapes suggests that microorganisms that develop on the grapes may contribute to the presence of this compound in wines.     

Images of asteroid 21 Lutetia: a remnant planetesimal from the early Solar System

Images obtained by the Optical, Spectroscopic, and Infrared Remote Imaging System (OSIRIS) cameras onboard the Rosetta spacecraft reveal that asteroid 21 Lutetia has a complex geology and one of the highest asteroid densities measured so far, 3.4 ± 0.3 grams per cubic centimeter. The north pole region is covered by a thick layer of regolith, which is seen to flow in major landslides associated with albedo variation. Its geologically complex surface, ancient surface age, and high density suggest that Lutetia is most likely a primordial planetesimal. This contrasts with smaller asteroids visited by previous spacecraft, which are probably shattered bodies, fragments of larger parents, or reaccumulated rubble piles.     

Laser Doppler flowmetry: muscular microcirculation in anaesthetized horses

Muscular microcirculation was studied in seven halothane anaesthetised horses in lateral recumbency using a laser Doppler flowmeter. A significant difference between the dependent and the uppermost triceps brachii was recorded. In the dependent muscles, microflow at first decreased and then increased up to the starting value. In the uppermost muscles, a significant rise of the microflow was measured.