Hygienic characteristics of radishes grown in soil contaminated with Stenotrophomonas maltophilia

Background: Stenotrophomonas maltophilia is a plant growth-promoter. This bacterium is also implicated in human diseases. Thus, after the use of this bacterium in agriculture, the safety of the final products has to be verified. Due to the ubiquitous presence of S. maltophilia in soil, in this study a massive contamination was simulated to evaluate the growth and safety of Raphanus sativus L.. Results: Different inoculums and soil treatment conditions were tested. Soils were analysed weekly and the radishes at harvest for their microbial loads and presence/persistence of S. maltophilia LMG 6606. The concentration of the bacterium added in the different trials decreased during the first week, but increased thereafter and determined a significant increase of growth parameters of radishes. Conclusions: The addition of S. maltophilia LMG 6606 to non-autoclaved soil enhanced the productivity of radishes. The bacterium did not internalize in the hypocotyls, but colonized the external surface ensuring the safety of the products. Thus, a sanitizing bath of hypocotyls before consumption is necessary

Thyrotropin-releasing hormone (TRH) promotes wound re-epithelialisation in frog and human skin

There remains a critical need for new therapeutics that promote wound healing in patients suffering from chronic skin wounds. This is, in part, due to a shortage of simple, physiologically and clinically relevant test systems for investigating candidate agents. The skin of amphibians possesses a remarkable regenerative capacity, which remains insufficiently explored for clinical purposes. Combining comparative biology with a translational medicine approach, we report the development and application of a simple ex vivo frog (Xenopus tropicalis) skin organ culture system that permits exploration of the effects of amphibian skin-derived agents on re-epithelialisation in both frog and human skin. Using this amphibian model, we identify thyrotropin-releasing hormone (TRH) as a novel stimulant of epidermal regeneration. Moving to a complementary human ex vivo wounded skin assay, we demonstrate that the effects of TRH are conserved across the amphibian-mammalian divide: TRH stimulates wound closure and formation of neo-epidermis in organ-cultured human skin, accompanied by increased keratinocyte proliferation and wound healing-associated differentiation (cytokeratin 6 expression). Thus, TRH represents a novel, clinically relevant neuroendocrine wound repair promoter that deserves further exploration. These complementary frog and human skin ex vivo assays encourage a comparative biology approach in future wound healing research so as to facilitate the rapid identification and preclinical testing of novel, evolutionarily conserved, and clinically relevant wound healing promoters