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Bacteria contain sigma (σ) factors that control gene expression in response to various environmental stimuli. The alternative sigma factors σFpvI and σPvdS bind specifically to the antisigma factor FpvR. These proteins are an essential component of the pyoverdine-based system for iron uptake in Pseudomonas aeruginosa. Due to the uniqueness of this system, where the activities of both the σFpvI and σPvdS sigma factors are regulated by the same antisigma factor, the interactions between the antisigma protein FpvR 20 and the σFpvI and σPvdS proteins have been widely studied in vivo. However, difficulties in obtaining soluble, recombinant preparations of the σFpvI and σPvdS proteins have limited their biochemical and structural characterizations. In this study, we describe a purification protocol that resulted in the production of soluble, recombinant His 6 -σFpvI/FpvR 1-67 , His 6 -σFpvI/FpvR 1-89 , His 6 -σPvdS/FpvR 1-67 and His 6 -σPvdS/FpvR 1-89 protein complexes (where FpvR 1-67 and FpvR 1-89 are truncated versions of FpvR 20) at high purities and concentrations, appropriate for biophysical analyses by circular dichroism spectroscopy and analytical ultracentrifugation. These results showed the proteins to be folded in solution and led to the determination of the affinities of the protein-protein interactions within the His 6 -σFpvI/FpvR 1-67 and His 6 -σPvdS/FpvR 1-67 complexes. A comparison of these values with those previously reported for the His 6 -σFpvI/FpvR 1-89 and His 6 -σPvdS/FpvR 1-89 complexes is made. • Pseudomonas aeruginosa His 6 -σFpvI/FpvR 1-67 , His 6 -σFpvI/FpvR 1-89 , His 6 -σPvdS/FpvR 1-67 and His 6 -σPvdS/FpvR 1-89. • A purification protocol for recombinant sigma/antisigma complexes is described. • The biophysical properties of these protein complexes are reported. [ABSTRACT FROM AUTHOR]

The extraction of metallic minerals and the mineral dressing operations in concentrators produced a high impact in soils and sediments. Heavy metals in soils constitute a high risk of pollution, not only for mining areas, but also for agriculture and villages placed in subsidiary areas. This research has been focused on the assessment of the real environmental and health hazards of Zn in relation to geochemistry and metal mobility in surface soils from a mining area in SE Spain, under semiarid weather conditions. Mineralogy of the studied soils revealed major presence of quartz, but also of other silicates, sulfates, carbonates, and sulfides. Regarding Zn minerals, the presence of sphalerite as the main Zn sulfide, and of goslarite as Zn sulfate, and of smithsonite as Zn carbonate should be highlighted. Soil pH ranged between 4.4 and 4.9 and the electrical conductivity between 55 and 85μS/cm. By using the sequential extraction procedure, the achieved results show that zinc is not only mainly associated to primary but also to secondary sulfides. Total concentration of the non-available fractions rises up to 98.45% of total Zn in the studied soils. On the other hand, available Zn fraction did not exceed more than 1.55% in percentage and less than 2000ppm in absolute terms, and when referred to more easily available fraction (water-soluble and exchangeable fractions), these values are not more than 0.44% and then 800ppm. Therefore, although there is a significant pollution level in this area, immediate hazard for the environment can be assessed as moderate. Finally it should be highlighted that these surface soils have undergone concentration processes of sphalerite, whose mechanisms should be related to the ascending flow of capillary water and the dragging of sphalerite crystals and Zn salts by electrokinetic and colloidal processes These processes seem to occur based on environmental pollution by wind and water erosion, and therefore directly associated to environmental pollution and risks by free metals. [Copyright &y& Elsevier]

Epidermal growth factor (EGF) and its receptor (EGF-R) are attractive targets for cancer immunotherapy. Tolerance has been broken with an EGF-vaccine and antibodies against EGF have been produced in animals and in cancer patients. EGF also plays an important role in the inflammation stage of wound healing. Because this therapeutic approach may be of importance after surgery procedures in cancer patients, we decided to investigate the possible role of the EGF-vaccine in the croton-oil-induced ear edema and in the wound healing experimental animal models.Mice were immunized with an EGF-vaccine by intramuscular injections and serum titers against EGF were measured through ELISA techniques. Control animals received saline.Immunized mice produced antibodies against EGF while no antibody titers could be measured in control animals. Croton oil applied to the inner ear surface of EGF-vaccine treated mice caused a 61.3% lower ear punch weight and a 60.2% lower myeloperoxidase activity than control mice. In the EGF-vaccine treated animals, planimetry measurements and histological analysis did not led to significant impairment in tissue repair.The EGF-vaccination in mice decreased the normal croton-oil-induced inflammation response, without apparent impairment in tissue healing. [Copyright &y& Elsevier]