Addressing quality and usability of surface water bodies in semi-arid regions with mining influences

Water resources management has considerable importance, specifically in the context of climate change. This subject has introduced new challenges in semi-arid regions with water quality problems, such as the Iberian Pyrite Belt, which is one of the largest metallogenetic provinces in the world and one of the driest regions in Europe. Positioned in the Mediterranean context, the region has a high density of polymetallic sulphide mines that promote the degradation of water systems. The present study aims to assess the water quality in the Pyrite Belt, considering a total of 34 surface water bodies, including constructed reservoirs, permanent and ephemeral streams, and mining facilities with accumulated water (e.g., pit lakes and mining dams). The water samples were analysed for physico-chemical properties, including field parameters (pH, electrical conductivity), alkalinity/acidity, hardness, anions, and potential toxic elements. The results were used for hydrochemical classifications and the assessment of suitability for public uses. Statistical methods, such as hierarchical cluster analysis and nearest centroid classifier, were used for grouping and evaluating the similarity between water bodies. Two groups were generated from the analysis: i) constructed lakes with alkaline and sodium signatures; and ii) waters suffering from the influence of mining wastes, e.g., showing high acidity, sulphate and metal contents. Therefore, the loss of water quality in the vicinity of mines reflects the impact of acid mine drainage. The methodological approach used may be applied to the integrated management of water resources in regions with mining influences and where it is necessary to combat drought and water scarcity scenarios.Patricia Gomes acknowledge FCT (Science and Technology Foundation, Portugal) by the research fellowship under the POCH (Programa Operacional Capital Humano) supported by the European Social Fund and National Funds of MCTES (Ministerio da Ciencia, Tecnologia e Ensino Superior) with reference SFRH/BD/108887/2015. This work was co-funded by the European Union through the European Regional Development Fund, based on COMPETE 2020 (Programa Operacional da Competitividade e Internacionalizacao) - project ICT (UID/GEO/04683/2013) with reference POCI-01-0145-FEDER-007690 and project Nano-MINENV number 029259

Involvement of sulfates from cruzipain, a major antigen of Trypanosoma cruzi, in the interaction with immunomodulatory molecule Siglec-E

In order to investigate the involvement of sulfated groups in the Trypanosoma cruzi host–parasite relationship, we studied the interaction between the major cysteine proteinase of T. cruzi, cruzipain (Cz), a sulfate-containing sialylated molecule and the sialic acid-binding immunoglobulin like lectin-E (Siglec-E). To this aim, ELISA, indirect immunofluorescence assays and flow cytometry, using mouse Siglec-E–Fc fusion molecules and glycoproteins of parasites, were performed. Competition assays verified that the lectins, Maackia amurensis II (Mal II) and Siglec-E–Fc, compete for the same binding sites. Taking into account that Mal II binding remains unaltered by sulfation, we established this lectin as sialylation degree control. Proteins of an enriched microsomal fraction showed the highest binding to Siglec-E as compared with those from the other parasite subcellular fractions. ELISA assays and the affinity purification of Cz by a Siglec-E column confirmed the interaction between both molecules. The significant decrease in binding of Siglec-E–Fc to Cz and to its C-terminal domain (C-T) after desulfation of these molecules suggests that sulfates contribute to the interaction between Siglec-E–Fc and these glycoproteins. Competitive ELISA assays confirmed the involvement of sulfated epitopes in the affinity between Siglec-E and Cz, probably modified by natural protein environment. Interestingly, data from flow cytometry of untreated and chlorate-treated parasites suggested that sulfates are not primary receptors, but enhance the binding of Siglec-E to trypomastigotic forms. Altogether, our findings support the notion that sulfate-containing sialylated glycoproteins interact with Siglec-E, an ortholog protein of human Siglec-9, and might modulate the immune response of the host, favoring parasitemia and persistence of the parasite.Fil: Ferrero, Maximiliano Ruben. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud “Dr. C. G. Malbrán”. Instituto Nacional de Parasitología ; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Heins, Anja M.. Bernhard Nocht Institute for Tropical Medicine; AlemaniaFil: Soprano, Luciana Lía. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud “Dr. C. G. Malbrán”. Instituto Nacional de Parasitología ; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Acosta, Diana Maria. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud “Dr. C. G. Malbrán”. Instituto Nacional de Parasitología ; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Esteva, Mónica Inés. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud “Dr. C. G. Malbrán”. Instituto Nacional de Parasitología ; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Jacobs, Thomas. Bernhard Nocht Institute for Tropical Medicine; AlemaniaFil: Duschak, Vilma Gladys. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud “Dr. C. G. Malbrán”. Instituto Nacional de Parasitología ; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin