Understanding the Environmental Impact of a Mine Dam Rupture in Brazil: Prospects for Remediation.

The rupture of the Fundão mine dam in Mariana municipality, Minas Gerais State, Brazil, spilled the tailings across the Doce River basin. These tailings, composed of residues discarded from the beneficiation of iron ore, are rich in SiO and AlO, as well as some ether amine compounds and NaOH. The aim of this study was to assess the distribution of these sediments, as well as their effect on the riparian zones reached, as compared with preserved sites. Sediment deposition in the river resulted in a morphological change from a meandering profile to a braided aspect. The nutrient and mineral content (P, K, Ca, Mg, Cu, Fe, Mn, Zn, and NO) and soil organic matter of the sediments were depleted, whereas NH, Na, and pH increased. A random presence of ether amines in the sediments was confirmed by quantitative and chromatographic analyses, with concentrations ranging from 0 to 57.8 mg kg; Na reached values as high as 150 mg kg. The impact of the dam tailings on biota was assessed by estimating total microbial biomass (phospholipid fatty acids), which were depleted in sediments relative to soils from preserved sites. Overall plant mortality, as well as a low resilience capacity, were also observed. Ether amines and Na present in the sediments had a strong toxic effect in the environment. Identification of these substances as the main impact factors will help guide future remediation efforts.

Extratos aquosos de inhame (Dioscorea rotundata Poirr. ) e de mastruz (Chenopodium ambrosioides L. ) no desenvolvimento da lagarta-do-cartucho-do-milho Spodoptera frugiperda (J. E. Smith, 1797) / Aqueous extracts of yam (Dioscorea rotundata Poirr. ) and chenopodium (Chenopodium ambrosioides L. ) in the development of fall armyworm Spodoptera frugiperda (J. E. Smith, 1797)

RESUMO: Estudou-se o efeito de extratos aquosos de inhame (0; 5; 10; e 20% p/p) e de mastruz (0; 2; 4; 6; 8 e 10% p/p) na biologia da lagarta-do-cartucho. Secções de folhas de milho foram mergulhadas por 30 segundos em soluções de cada concentração; após a secagem, colocou-se em cada secção uma lagarta recém-eclodida. Foram avaliadas a viabilidade e a duração das fases larval e pupal, peso e comprimento das lagartas e pupas. Em relação ao extrato de inhame, a concentração de 20% causou maior influência na fase larval, sendo a viabilidade reduzida para 12%, com duração de 7 dias, diferindo da testemunha com 17 dias. O extrato da mesma planta a 10% causou 48% de mortalidade. Em todas as concentrações esse extrato também afetou a fase de pupa; na testemunha, 85% das pupas foram viáveis, enquanto nos demais tratamentos a viabilidade não excedeu a 25%. Para o peso e comprimento das lagartas, os resultados não foram significativos. Para o mastruz, o extrato a 20% causou influência na fase larval com baixa viabilidade e mortalidade logo nos primeiros seis dias de avaliação. Outras concentrações de mastruz não deferiram entre si nas fases larval e pupal. Verificou-se que a alimentação das lagartas com folhas tratadas com mastruz diminuiu o peso das pupas.

ABSTRACT: The effect of aqueous extracts of yam (0, 5, 10, and 20% h/h) and chenopodium (0, 2, 4, 6, 8 and 10% h/h) on the biology of fall armyworm was studied. Sections of maize leaves were dipped for 30 seconds in solutions of each concentration; after the section dried, a recently hatched caterpillar was placed onto each treated section. The viability and duration of the larval and pupal stages and the weight and length of the caterpillars and pupae were evaluated. For yam, the extract at 20% concentration caused the greatest influence on the larval stage of the insect, significantly reducing larval viability to 12%, with 7 day larval stage duration, differing from the control at 17 days. The extract of the same plant at 10% caused 48% larval mortality. At all concentrations, that extract also affected the pupal stage; in the control, pupal viability was 85%, whereas for the other concentrations the viability did not exceed 25%. No significant differences were observed for the weight and length of caterpillars. For chenopodium, the extract at 20% concentration caused influence on the larval stage, as it showed the lowest viability, causing mortality in six days. Other chenopodium concentrations did not show differences for the larval and pupal stages. Feeding caterpillars with leaves treated with the extract of chenopodium decreased pupal weight.

Hyptis pectinata essential oil: chemical composition and anti-Streptococcus mutans activity.

OBJECTIVES: The aim of the present study was to evaluate the anti-Streptococcus mutans activity of Hyptis pectinata essential oil, and present its promising potential against oral diseases. MATERIALS AND METHODS: The essential oil of H. pectinata was obtained by hydrodistillation from dried leaves and analyzed by GC / MS. The effectiveness of this essential oil regarding the antimicrobial activity against several S. mutans strains was investigated by the agar diffusion and microdilution methods, and chlorohexidine was used as a standard control. RESULTS: The H. pectinata essential oil exhibited considerable inhibitory effect against either all the clinical isolates obtained from patients' saliva or the ATCC strains tested, with minimum inhibitory and bactericidal concentrations of 200 microg ml(-1). The study also compared the efficiency of the emulsifying agents Tween 20, Tween 80, dimethyl sulfoxide and propylene glycol in H. pectinata essential oil when tested against S. mutans. The data obtained confirmed the better inhibitory effect of the oil when using all tested diluents, although Tween 80 seemed to be more suitable for emulsification. CONCLUSION: According to our results, H. pectinata essential oil can be considered a promising alternative to chlorhexidine for the control of oral bacteria-related diseases and hygiene.

Antifungal activity of Brazilian medicinal plants involved in popular treatment of mycoses.

A survey of medicinal plants used to treat common mycoses was done in the Curituba district, Sergipe State, Brazil. One hundred inhabitants were interviewed by health agents and traditional healers. Four different plants were the most cited (more than 50% of the citations): Ziziphus joazeiro, Caesalpinia pyramidalis, Bumelia sartorum and Hymenea courbaril. The aqueous extracts obtained following traditional methods and using different parts of these plants, were submitted to drop agar diffusion tests for primary antimicrobial screening. Only the water infusion extract of Ziziphus joazeiro and Caesalpinea pyramidalis presented a significant antifungal activity against Trichophyton rubrum, Candida guilliermondii, Candida albicans, Cryptococcus neoformans and Fonsecaea pedrosoi, when compared to the antifungal agent amphotericin B. The minimal inhibitory concentration (MIC) of the bioactive extracts was evaluated by the microdilution method. Best activity with a MIC of 6.5 microg/ml for both extracts was observed against Trichophyton rubrum and Candida guilliermondii. Ziziphus joazeiro and Caesalpinea pyramidalis extracts presented also low acute toxicity in murine models. The present study validates the folk use of these plant extracts and indicates that they can be effective potential candidates for the development of new strategies to treat fungal infections.