Detection of airborne genetically modified maize pollen by real-time PCR.

The cultivation of genetically modified (GM) crops has raised numerous concerns in the European Union and other parts of the world about their environmental and economic impact. Especially outcrossing of genetically modified organisms (GMO) was from the beginning a critical issue as airborne pollen has been considered an important way of GMO dispersal. Here, we investigate the use of airborne pollen sampling combined with microscopic analysis and molecular PCR analysis as an approach to monitor GM maize cultivations in a specific area. Field trial experiments in the European Union and South America demonstrated the applicability of the approach under different climate conditions, in rural and semi-urban environment, even at very low levels of airborne pollen. The study documents in detail the sampling of GM pollen, sample DNA extraction and real-time PCR analysis. Our results suggest that this 'GM pollen monitoring by bioaerosol sampling and PCR screening' approach might represent an useful aid in the surveillance of GM-free areas, centres of origin and natural reserves.

Culture and spray-drying of Tsukamurella paurometabola C-924: stability of formulated powders.

The nematocidal agent, Tsukamurella paurometabola C-924, was cultured in a 300 l bioreactor. Spray-dried formulations of this microorganism were prepared using sucrose. At an outlet temperature 62 degrees C, survival rates between 12 and 85% were reached with sucrose up to 10% (w/w). The stability study of the powders showed that the best storage condition was at 4 degrees C under vacuum. A new method for the calculation of cell death order for bacteria stored at low temperatures was developed. Powders stored under vacuum showed an Arrhenius behavior in relation to cell death kinetics.

Evaluation of the operating performance of conventional versus flocculator secondary clarifiers at the Kuwahee Wastewater Treatment Plant, Knoxville, Tennessee.

The difference in performance of three differently designed circular secondary clarifiers in the same wastewater treatment plant was analyzed in this paper. Data obtained using flocculated suspended solids and disperse suspended solids tests were analyzed using statistical tools. The conventional clarifier showed more variability in the average effluent suspended solids concentration when compared with the flocculator-clarifiers. Furthermore, a difference in performance among the two different flocculator-clarifiers was found.

Micronuclei induced by airborne particulate matter from Mexico City.

Particulate air pollution is an important environmental health risk. In the present study, we have investigated the ability of chemically characterized water and organic-soluble extracts of PM(10) from two different regions of Mexico City to induce micronuclei in a human epithelial cell line. We also evaluated the association between the chemical characteristics of the PM and its genotoxicity. The airborne particulate samples were collected from an industrial and a residential region; a Hi-Vol air sampler was used to collect PM(10) on glass fiber filters. PM mass was determined by gravimetric analysis of the filters. One section of each PM(10) filter was agitated either with deionized water to extract water-soluble compounds or with dichloromethane to prepare organic-soluble compounds. The chemical composition of the extracts was determined by ion and gas chromatography and atomic adsorption spectroscopy. A549-human alveolar epithelial cells were exposed to different concentrations of PM(10) extracts and the cytokinesis blocked micronucleus assay was performed to measure DNA damage. Even though the industrial region had a higher PM concentration, higher amounts of metals and PAHs were found in the residential area. Both industrial and residential extracts induced a significant concentration-related increase in the micronuclei frequency. The PM(10) water-soluble industrial extract induced significantly more micronuclei than the one of the residential region; inversely, the organic residential extract induced more micronuclei than the one from the industrial region. The association between the induction of micronuclei and the chemical components obtained by the comparative analysis of standardized regression coefficients showed that cadmium and PAHs were significantly associated with micronuclei induction. Data indicate that water-soluble metals and the organic-soluble fraction of PM(10) are both important in the production of micronuclei. Effects observed, point to the risk of PM exposure and shows the need of integrative studies.