8 research outputs found

    Genotoxic potential generated by biomass burning in the Brazilian Legal Amazon by Tradescantia micronucleus bioassay: a toxicity assessment study

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>The Brazilian Amazon has suffered impacts from non-sustainable economic development, especially owing to the expansion of agricultural commodities into forest areas. The Tangará da Serra region, located in the southern of the Legal Amazon, is characterized by non-mechanized sugar cane production. In addition, it lies on the dispersion path of the pollution plume generated by biomass burning. The aim of this study was to assess the genotoxic potential of the atmosphere in the Tangará da Serra region, using <it>Tradescantia pallida </it>as <it>in situ </it>bioindicator.</p> <p>Methods</p> <p>The study was conducted during the dry and rainy seasons, where the plants were exposed to two types of exposure, active and passive.</p> <p>Results</p> <p>The results showed that in all the sampling seasons, irrespective of exposure type, there was an increase in micronucleus frequency, compared to control and that it was statistically significant in the dry season. A strong and significant relationship was also observed between the increase in micronucleus incidence and the rise in fine particulate matter, and hospital morbidity from respiratory diseases in children.</p> <p>Conclusions</p> <p>Based on the results, we demonstrated that pollutants generated by biomass burning in the Brazilian Amazon can induce genetic damage in test plants that was more prominent during dry season, and correlated with the level of particulates and elevated respiratory morbidity.</p

    Bartonella quintana Variably Expressed Outer Membrane Proteins Mediate Vascular Endothelial Growth Factor Secretion but Not Host Cell Adherence

    No full text
    Bartonella quintana causes trench fever, endocarditis, and the vasculoproliferative disorders bacillary angiomatosis and peliosis hepatis in humans. Little is known about the interaction of this pathogen with host cells. We attempted to elucidate the interaction of B. quintana with human macrophages (THP-1) and epithelial cells (HeLa 229). Remarkably, only B. quintana strain JK-31 induced secretion of vascular endothelial growth factor (VEGF) from THP-1 and HeLa 229 cells upon infection similar to the secretion induced by B. henselae Marseille, whereas other strains (B. quintana 2-D70, B. quintana Toulouse, and B. quintana Munich) did not induce such secretion. Immunofluorescence testing and electron microscopy revealed that the B. quintana strains unable to induce VEGF secretion did not express the variable outer membrane proteins (Vomps) on their surfaces. Surprisingly, the increase in VEGF secretion mediated by B. quintana JK-31 was not paralleled by elevated host cell adherence rates compared with the rates for Vomp-negative B. quintana strains. Our results suggest that the Vomps play a leading role in the angiogenic reprogramming of host cells by B. quintana but not in the adherence to host cells

    Tracing elevational changes in microbial life and organic carbon sources in soils of the Atacama Desert

    No full text
    The Atacama Desert frequently serves as model system for tracing life under extremely dry conditions. We hypothesized that traces of life in the Atacama Desert follow distinct micro- and macro-scale gradients such as soil depth and elevation, respectively. Different depth intervals of surface soils (0–1, 1–5, and 5–10 cm) were sampled at five sites along an elevational transect near the Quebrada Aroma, spanning from the hyperarid core of the desert towards the arid Western Andean Precordillera (1300 to 2700 m a.s.l.), and from one additional site in the hyperarid core near Yungay. We determined the contents of major elements, pedogenic minerals and oxides, organic carbon (OC), and its δ13C and δ15N isotopic composition. The presence of living microorganisms was assessed by cultivation, and bacterial community composition was analyzed based on 16S rRNA gene sequencing. Additional information about past and present plant and microbial life was obtained from lipid biomarker analysis. We did not detect consistent micro-scale distributions for most of these proxies within the soils. However, concentrations of OC and of long-chain, plant wax-derived n-alkanes increased in soils along the aridity gradient towards the wetter sites, indicating the presence of past life at places presently not covered by vegetation. Likewise, bacterial abundance and diversity decreased as hyperaridity increased and the microbial community composition changed along the transect, becoming enriched in Actinobacteria. The distributional patterns of phospholipid fatty acids (PLFAs) confirmed the larger bacterial diversity at the higher, more humid sites compared to the drier ones. Archaeal isoprenoid glycerol dialkyl glycerol tetraethers (isoGDGTs) and bacterial branched (br)GDGTs, which can also indicate past life, did not follow a clear elevational trend and were absent at the driest site. Taken together, plant-derived and microbiological markers follow primarily the macro-scaled elevation and aridity gradient. Viable bacteria are present even at the driest sites, while detected biomolecules also indicate past life. The detection of past plant life in nowadays apparently lifeless regions suggests that conditions for life were less hostile in former times
    corecore