Improvements in trace enrichment techniques combined with the sensitivity of mass spectrometry offer enhanced opportunities to analyze ever lower concentrations of drugs, metabolites, pesticides or ...environmental pollutants. To perform HPLC and liquid chromatography–mass spectrometry (LC–MS) analyses under optimum conditions, the water used for mobile phase preparation needs to be highly purified and delivered on demand. Indeed, both UV photodiode array detection and MS detection methods are sensitive to organic contaminants (total organic carbon, TOC), and the water quality has a direct impact on the achievable detection limits. The benefits of UV photooxidation on TOC reduction for LC–MS studies were highlighted using electrospray ionization MS detection by comparing HPLC-grade bottled water, freshly produced UV185/254-treated water, and freshly produced non-UV-treated water.
Ceramides and distearoylphosphatidylcholine (DSPC) were incorporated in various liposomes preparations in comparison with dipalmitoylphosphatidylcholine alone. Preparations were introduced in an ...‘Artificial Stomach-Duodenum’ model to improve their stability. Better results were observed for DSPC and ceramide-containing liposomes. Entrapment of CuZn Superoxide dismutase (SOD) in liposomes have been carried out for oral administration. The efficiency of entrapment of SOD was 35.4% for liposomes without ceramides, and from 24.3% to 46.1% for ceramide-containing liposomes.
Acid Neutralisation and Sulphur Retention in S-Impacted Andosols. La difficulté de planter des arbres fruitiers et forestiers dans les zones semi-arides provient du besoin en eau très important dès ...la plantation et durant toute la phase de croissance. Une nouvelle méthode d'irrigation par semi-conduite verticale, mise au point au Sénégal permet d'arroser les jeunes plants avec de faibles quantités d'eau et de réussir des plantations dans ces zones semi-arides. Avec le succès de cette méthode, le développement des vergers de manguiers et d'anacardiers va générer une production importante de fruits qui risque, à court terme, de saturer le marché si la filière n'est pas organisée à temps. L'auteur décrit la nouvelle technique d'irrigation et prévient de l'urgence d'organiser les groupements de producteurs et la filière fruitière.
Concentrations of mercury and persistent organic pollutants in fish were examined in 11 lakes of the French Pyrénées spanning an elevation range of 2
km. All lakes were confined to a relatively small ...area within a 50-km diameter. Most of the lakes were within the Pyrénées National Park, which is restricted to recreational hiking, angling, and seasonal grazing of livestock, and are not subject to any known point sources of contaminants. Fish collected were mainly of 1 species (
Salmo trutta fario), which is stocked regularly in the lakes. With increasing elevation, lake temperatures declined along with electrical conductivity and planktonic chlorophyll
a. In contrast, water column nutrients (total phosphorus and total nitrogen) and epilithic periphyton biomass were not correlated with lake elevation. Of the global contaminants measured in fish, mercury, dicholorodiphenyltrichloroethane and its derivatives, and polybrominated diphenyl ethers showed the strongest positive correlation with elevation. Hg levels in some fish exceeded health consumption guidelines in these mountain lakes. Variation in fish contaminant levels was not related to differences in growth rate or to fish trophic position as determined using
δ
15N stable isotope measurements. This implies that the delivery and/or retention of many of these contaminants increase with lake elevation.
The behavior and biochemical adaptations of 3 generalist insect species (Tettigonia viridissima L., Ruspolia nitidula Scopoli, and Conocephalus discolor Thunberg) and 3 specialists (Galeruca tanaceti ...L., Chrysolina geminata Payrtull, and Cloantha perspicillaris Boisduval) to the hypericin-containing leaves of Hypericum perforatum were investigated in southwestern France. The generalists preferentially fed on the part of the leaf lacking the phototoxic, hypericin-laden dark glands. The specialists showed no discriminatory feeding pattern but exhibited a negative phototaxis that is presumed to be an efficient strategy to circumvent the light-induced toxicity of hypericin. The constitutive and hypericin-inducible activities of glutathione reductase and glutathione S-transferase, 2 antioxidant enzymes which are considered to be biochemical adaptations used by phytophagous insects to attenuate the oxidative stress caused by photosensitization, were determined in the fatbody and midgut of T. viridissima, C. discolor, G. tanaceti, and G. geminata. The specialist insects had lower constitutive activities of glutathione S-transferase and glutathione reductase than the generalists, although the application of hypericin induced the activity of glutathione S-transferase in specialist insects only. Insects with different lifestyles therefore are capable of circumventing the phototoxic effects of hypericin by appropriate behavioral and biochemical strategies.
Crops of maize (Zea mays L.) were conducted in southwestern France with GMO (Genetic Modified Organism) vs isogenetic varieties in order to verify the control of European Corn Borer (ECB) Ostrinia ...nubilalis (Hübner) and the Corn Stalk Borer (CBS) Sesamia nonagrioides (Lefevbre) by GMO in field conditions. The bioassays were carried out in 1998 and 1999 before moratorium, then in 2005. Experiments involved respectively 18, 12 and 19 fields cultivated with Furio/Furio cb (GMO), Cecilia/ Elgina (GMO) and PR33P66/PR33P67 (GMO) varieties. These transgenic events expressed Cry1A(b) protein (Bt maize). Plants were noted for insect infestation assessment (number of larvae in stalks and ears per plant). Statistical tests used t-test on couple of plots. Results showed a significant difference in the density of both ECB and CBS between control and the two transgenic events. The two transgenic events acted differently. The control of the two Bt events on the two pests were differentiated and discussed. These experiments underlined the importance of field evaluation for testing real effects of transgenic events on crop according the environmental context.
Formation of free radicals and lipoperoxidation occur at the onset of cellular damage. These effects are produced during normal metabolism and in pathological states. The peroxidation of ...polyunsaturated fatty acids, i.e. linoleic acid and linolenic acid, which are both cellular membrane compounds, induces ethane and pentane formation in pulmonary air exhalation. These two volatile hydrocarbons can be considered as potential lipoperoxidation markers. Methodological difficulties limit the use of these gases for assessment of free oxygen radical activity but we have developed and validated a non-invasive technique. A study was performed with ten healthy volunteers.
Four trichothecene-producing strains of Fusarium graminearum were grown on three maize grain fractions, whole grain, degermed grain, and the germ, to determine the effect of natural substrates on ...mycotoxin production. Monitoring the ergosterol content after 25 days of incubation indicated that fungal growth on all grain fractions was comparable. Trichothecene (TCT) production was highest on degermed grain, less on whole grain, and very low or nondetectable on the germ; similar results were found with four different strains. It was concluded that inhibitor(s) of TCT biosynthesis were present in maize germ. The presence of phenolic compounds was investigated in the different fractions. The hydroxamate 4-acetylbenzoxazolin-2-one (4-ABOA), a known inhibitor of mycotoxin production, was found in the degermed and whole grain fractions but not in the germ. Therefore, the TCT inhibition observed on the maize germ fraction used in our study is clearly not linked to 4-ABOA. Other soluble phenolic compounds were found at a much higher concentration in the germ than in the two other fractions. The inhibition property of the soluble ester-bound extracts was tested in liquid culture. A possible role for these compounds is discussed. Keywords: Fusarium; mycotoxins; trichothecenes; phenolic compounds; maize
The toxic activity of some characteristic monoterpenoids:
p-cymene, α-pinene, camphor, linalool, terpineol, cuminaldehyde, cinnamaldehyde, anethole, carvacrol, thymol, estragole and eugenol, was ...tested against
Acanthoscelides obtectus (Say), a bruchid pest of kidney bean (
Phaseolus vulgaris L.). A fumigant toxic effect was observed and LC
50 concentrations for 24h and 48h were calculated for adults.
Besides this effect, a reproductive inhibition was observed. This inhibition involved female fecundity, oviposition, and the development of neonate and intracotyledonal larvae. The effects of monoterpenes on oviposition, larval penetration inside the seeds and emergence were determined. All monoterpenes revealed a more or less pronounced vapour toxicity and significantly inhibited beetle reproduction. Oxygenated monoterpenoids: carvacrol, thymol, eugenol, linalool and terpineol were identified as the most efficient compounds in both respects and the structure-activity relationship is discussed.
