Role of natural nanoparticles, imogolite and allophane, on the mobility of trace metals in soils from La Reunion Island

This research adresses the sensitive field of waste management in an insular context. The case of the Reunion Island bears some aggravating factors making the waste management an even more sensitive subject: 1) it is a small island with a fast growing population and associated activities 2) the agricultural soils (mostly andosols) have an elevated natural concentration of trace metals. An inexpensive form of waste management is to reuse agricultural- waste (especially pig manure) as fertilizer. However, reuse of waste, may modify physico-chemical conditions and trace elements can be released from the soils. The accuracy of the prediction of metal fluxes in soils will be greatly enhanced by a detailed knowledge of the pollutants' speciation, which controls their mobility, toxicity and ultimately their bioavailability. Although the trace metals Cu, Ni, Zn selected for this study because of their occurrence in the soils and wastes, may bind to numerous components of the soils (clays, Fe and Al oxides, organics), we chose to focus on 2 types of nanosized alumino-silicates: the tubular imogolites (2nm diameter) and the spherical allophane (3-5nm). The choice of these phases is justified by their high abundance in the andosols of the Reunion, and their suspected high reactivity arising from the presence of -SiOH and -AlOH at the surface of structures whose specific surface area can reach 700m2/g. Here we detail using a molecular approach the types of the binding mechanisms between pollutants and natural occurring nanoparticles. (Texte integral

Rickettsias del grupo de las fiebres manchadas en garrapatas del género Amblyomma, capaces de infestar humanos, en áreas rurales del noroeste de Argentina

This work was performed to detect Rickettsia species of the spotted fever group in Amblyomma ticks likely to infest humans in rural areas from northwestern Argentina. Free-living ticks were collected and determined as Amblyomma tigrinum, Amblyomma neumanni and Amblyomma tonelliae. Rickettsia infection was determined by polymerase chain reactions which amplify fragments of the rickettsial genes gltA and ompA. A high frequency (35/44, 79.5%) of Candidatus “Rickettsia andeanae” was observed in A. tigrinum ticks, and Candidatus “Rickettsia amblyommii” was found in three out of 14 nymphs of A. neumanni. All 14 Amblyomma tonelliae ticks were negative for rikettsiae. The infection with spotted fever group rickettsiae in ticks aggressive for humans reveals the potential risk of exposure to tick-borne pathogens of people inhabiting rural areas of northwestern Argentina.Fil: Saracho Bottero, María Noelia. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Santa Fe. Estación Experimental Agropecuaria Rafaela; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; ArgentinaFil: Tarragona, Evelina Luisa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Santa Fe. Estación Experimental Agropecuaria Rafaela; ArgentinaFil: Nava, Santiago. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Santa Fe. Estación Experimental Agropecuaria Rafaela; Argentin

SCD5 restored expression favors differentiation and epithelial-mesenchymal reversion in advanced melanoma

Our previous data supported a role for the Stearoyl-CoA desaturase (SCD5) in protection against malignancy, whereby it appears to functionally modify tumor stroma impairing tumor spread. SCD5 is significantly expressed in primary melanoma, but becomes barely detectable at tumor advanced stages. Looking for the regulatory mechanisms underlying SCD5 reduced expression during melanoma progression, we demonstrated a significantly lower stability of SCD5 protein as well as the direct targeting of SCD5 mRNA by the oncogenic miR-221 & 222 in metastatic cell lines. Moreover, our results indicated the existence of a negative feedback loop between SCD5 and miR-221 & 222, in good agreement with their opposite functions. Also, we showed how SCD5 re-expression and the direct supplementation of its main product oleic acid (OA) can drive advanced melanoma cell lines toward differentiation and reversion of the epithelial-mesenchymal (EMT)-like process, eventually inducing a less malignant phenotype. Indeed, SCD5 re-established the sensitivity to all-trans retinoic acid in A375M metastatic melanoma, associated with increased levels of Tyrosinase, melanin production and reduced proliferation. As evidenced by the correct modulation of some key transcription factors, SCD5 managed by favoring a partial mesenchymal-to-epithelial (MET) transition in in vitro studies. Interestingly, a more complete MET, including E-cadherin re-expression correctly localized at cell membranes, was obtained in in vivo xenograft models, thus indicating the requirement of direct contacts between tumor cells and the surrounding microenvironment as well as the presence of some essential factors for SCD5 complete function

Membrane vesicles derived from Bordetella bronchiseptica: Active constituent of a new vaccine against infections caused by this pathogen

Bordetella bronchiseptica, a Gram-negative bacterium, causes chronic respiratory tract infections in a wide variety of mammalian hosts, including humans (albeit rarely). We recently designed Bordetella pertussis and Bordetella parapertussis experimental vaccines based on outer membrane vesicles (OMVs) derived from each pathogen, and we obtained protection against the respective infections in mice. Here, we demonstrated that OMVs derived from virulent-phase B. bronchiseptica (OMVBbvir+) protected mice against sublethal infections with different B. bronchiseptica strains, two isolated from farm animals and one isolated from a human patient. In all infections, we observed that the B. bronchiseptica loads were significantly reduced in the lungs of vaccinated animals; the lung-recovered CFU were decreased by ≥4 log units, compared with those detected in the lungs of nonimmunized animals (P < 0.001). In the OMVBbvir+-immunized mice, we detected IgG antibody titers against B. bronchiseptica whole-cell lysates, along with an immune serum having bacterial killing activity that both recognized B. bronchiseptica lipopolysaccharides and polypeptides such as GroEL and outer membrane protein C (OMPc) and demonstrated an essential protective capacity against B. bronchiseptica infection, as detected by passive in vivo transfer experiments. Stimulation of cultured splenocytes from immunized mice with OMVBbvir+ resulted in interleukin 5 (IL-5), gamma interferon (IFN-γ), and IL-17 production, indicating that the vesicles induced mixed Th2, Th1, and Th17 T-cell immune responses. We detected, by adoptive transfer assays, that spleen cells from OMVBbvir+-immunized mice also contributed to the observed protection against B. bronchiseptica infection. OMVs from avirulent-phase B. bronchiseptica and the resulting induced immune sera were also able to protect mice against B. bronchiseptica infection.Fil: Bottero, Daniela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Biotecnología y Biología Molecular. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Biotecnología y Biología Molecular; ArgentinaFil: Zurita, Maria Eugenia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Biotecnología y Biología Molecular. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Biotecnología y Biología Molecular; ArgentinaFil: Gaillard, María Emilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Biotecnología y Biología Molecular. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Biotecnología y Biología Molecular; ArgentinaFil: Bartel, Erika Belén. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Biotecnología y Biología Molecular. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Biotecnología y Biología Molecular; ArgentinaFil: Vercellini, María Clara. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Estudios Inmunológicos y Fisiopatológicos. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Estudios Inmunológicos y Fisiopatológicos; ArgentinaFil: Hozbor, Daniela Flavia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Biotecnología y Biología Molecular. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Biotecnología y Biología Molecular; Argentin

Decision-making tools for urban regeneration processes: from Stakeholders Analysis to Stated Preference Methods

Urban regeneration operations are connected to the creation of a multiplicity of benefits, both economic and extra-economic, that range from the increase in the environmental quality to the amelioration of the urban image, from the valorization of the cultural heritage to the creation of economic development processes. The articles aims at proposing an integrated evaluation approach for addressing decision problems in the context of urban regeneration operations. Starting from the real case of the regeneration programme of the city of Collegno (Italy), the contribution proposes an original evaluation model based on the combined use of Stakeholders Analysis and Stated Preference Methods. The results of the research shows the people’s perception about the social value of urban regeneration programme and their Willingness To Pay for specific transformation operations

A mixed methods approach for the integration of urban design and economic evaluation: industrial heritage and urban regeneration in China

This paper presents the early results of a study aimed at experimenting an innovative approach to the design and the evaluation of complex urban transformation processes, based on the combined use of different design strategies and tools. The purpose of the paper is to illustrate, by means of a case study, a multi-level decision aiding process, able to support strategic urban design, with specific reference to regeneration processes for abandoned industrial sites in urban areas. The case study presented in the paper concerns different alternative proposals for the requalification of the former Shougang/Er-Tong mechanical factory in Beijing, China. The choice of a Chinese case study as a field test for an experimentation about mixed methods research approaches in the domain of urban transformation is related to the peculiar emerging conditions of that context, in which huge economic potentials are speeding up the transformation but a substantial lack of cultural and methodological instruments to manage a so fast modification exists. During the design process, three methods in particular have been combined according to a multi-phase design: (i) Stakeholders Analysis, (ii) Multicriteria Analysis, and (iii) Discounted Cash Flow Analysis. Each one of them has been applied in parallel to the evolution of the different design scenarios. The results of the performed study show that mixed methods approaches are a promising line of research in the field of environmental evaluation and urban design. Insights and guidelines for the replication of the proposed methodological approach in other territorial contexts are also proposed

Mechanisms of formation and reactivity of imogolite types material

Reactivity of nanopar8cles represents a central issue for many laboratories around the world. Among many supported efforts the control of the morphology of nanopar8cles is mo8vated by the fact that morphology strongly influence the proper8es of the final products. Among the vast family of available nanopar8cles, imogolite is a clay nanotube for which perfect control of the diameter is possible. Imogolites were first observed in volcanic soils[1]. They are natural aluminosilicate nanotubes having the general formula (OH)3Al2O3SiOH with a 2 nm external diameter and up to micrometers in length. The impressive monodispersity in imogolite nanotube diameter has mo8vated research on their forma8on mechanism. Synthesis protocols to produce imogolite were quickly developed. Farmer et al. were the first to obtain synthe8c imogolite using low concentra8ons of AlCl3 and SiO 2 monomers as star8ng materials (millimolar concentra8ons of the reagents) [2]. However, the produc8on of large amount of imogolite or imogolite type materials remained challenging for long 8me. We will present our most recent results concerning the possibility to produce imogolite type materials from highly concentrated stock solu8ons. We will also detail the possibility to form double wall Al- Ge nanotubes and the different stages of their forma8on [3-7]. We will then detail the surface reac8vity of these nanotubes toward metals at he lab scale as well as in natural soil. (Résumé d'auteur

Copper and zinc speciation in pig slurry: implications on mobility and bioavailability in soils

The fate of pollutants associated with organic wastes is a key issue. For example, pig slurry presents high concentration of Copper (Cu) and Zinc (Zn) since they are used (at high concentration) as essential micronutrients in animal feeds. As a consequence, Cu and Zn accumulation was measured in soil surface layers that had been amended with pig slurry, inducing phytotoxicity as well as groundwater quality degradation. Better prediction of the mobility and bioavailability of Cu and Zn from pig slurry spreading can be achieved by determining the speciation of these elements. The aim of this study is to investigate Cu and Zn speciation in pig slurry. A multitechnique approach was adopted including size fractionation, XRD, SEM-EDS, ?XRF and XAS. The present study demonstrated that only 0.2% of total Cu or Zn present in pig slurry was bound to particles smaller than 0.45 ?m, while 75% of total Cu and Zn was bound to particles in the 0.45-20 ?m size range. ?XRF highlighted the colocalisation of Cu and sulfur. In addition, geochemical modelling demonstrated that physical chemical conditions within pig slurry lagoon are compatible with the precipitation of chalcocite (Cu2S). Finally, XANES shows that Cu speciation in raw pig slurry and size fractions is described by Cu2S and that its oxidation state is Cu(I). These Cu speciation in pig slurry may be the main reason for the observed Cu accumulation at the soil surface. Zn speciation revealed three patterns 49% Zn bound to organic matter, 37% amorphous Zn hydroxide, and 14% sphalerite (ZnS). The detected presence Zn sulphide, was unexpected and is reported for the first time. These three Zn forms seemed to be soluble in neutral or weakly acid soil systems, so the long-term impact of pig slurry spreading could lead to Zn leaching. (Résumé d'auteur