Maintaining the cultivation of vegetables with low Pb accumulation while remediating the soil of an allotment garden (Nantes, France) by phytoextraction.

Lead (Pb) is commonly found in urban soils and can transfer to vegetables. This entails a health risk for consumers of garden crops. The increasing demand of gardening on urban soil linked to the population increase and concentration in urban areas induces an increase in the risk, as people could be forced to cultivate contaminated soils. The aim of this study was to evaluate the performance of a cropping system that allows simultaneously (i) growing eatable vegetables that accumulate few Pb and (ii) cleaning up the soil with other plants by phytoextraction. The tests were carried out in an allotment garden (Nantes, France) where soils are moderately enriched by Pb from geogenic origin (178 mg.kg-1 of dry soil on average). Four vegetables known to accumulate slightly Pb (Solanum lycopersicum, Brassica oleracea cv. "Capitata," Solanum tuberosum, and Phaseolus vulgaris) were grown. The in situ ability of Brassica juncea L. to progressively absorb the phytoavailable Pb of the soil was assessed during four seasons. Analyses of the edible parts of the four vegetables confirmed that they can all be safely cultivated. The accumulation of Pb in B. juncea shoots was too low (ca. 1 mg.kg-1 of dry matter at best) for phytoextraction purposes. Our results confirm that it is possible to grow very low Pb-accumulating vegetables on soils moderately contaminated with Pb, although it was not possible to reduce phytoavailable Pb rapidly enough with B. juncea. This study identifies possible avenues of research to improve this cropping system by using appropriate vegetables that will allow food production to continue on moderately contaminated soil while cleaning it up.

Docosahexaenoic acid inhibits the invasion of MDA-MB-231 breast cancer cells through upregulation of cytokeratin-1.

Docosahexaenoic acid (DHA), the main member of the omega-3 essential fatty acid family, has been shown to reduce the invasion of the triple-negative breast cancer cell line MDA-MB-231, but the mechanism involved remains unclear. In the present study, a proteomic approach was used to define changes in protein expression induced by DHA. Proteins from crude membrane preparations of MDA-MB-231 cells treated with 100 µM DHA were separated by two-dimensional electrophoresis (2-DE) and differentially expressed proteins were identified using MALDI-TOF mass spectrometry. The main changes observed were the upregulation of Keratin, type Ⅱ cytoskeletal 1 (KRT1), catalase and lamin-A/C. Immunocytochemistry analyses confirmed the increase in KRT1 induced by DHA. Furthermore, in vitro invasion assays showed that siRNA against KRT1 was able to reverse the DHA-induced inhibition of breast cancer cell invasion. In conclusion, KRT1 is involved in the anti-invasive activity of DHA in breast cancer cells.