Comparing organic versus conventional soil management on soil respiration.

Soil management has great potential to affect soil respiration. In this study, we investigated the effects of organic versus conventional soil management on soil respiration.  We measured the main soil physical-chemical properties from conventional and organic managed soil in Ecuador. Soil respiration was determined using alkaline absorption according to Witkamp.  Soil properties such as organic matter, nitrogen, and humidity, were comparable between conventional and organic soils in the present study, and in a further analysis there was no statically significant correlation with soil respiration. Therefore, even though organic farmers tend to apply more organic material to their fields, but this did not result in a significantly higher CO2 production in their soils in the present study.

Modelling risk using Bayes theorem of infection by antibiotic-resistant Escherichia coli in rural and urban populations of Ecuador.

Strains of antibiotic-resistant bacteria have become more and more prevalent. This has attracted the attention of health agencies worldwide, leading to an urgent search for mechanisms to put a stop to this phenomenon. This study focuses on estimating the probability of a person in Ecuador (at potential risk) contracting an infection due to ampicillin-resistant Escherichia coli through the consumption of contaminated water, for which a residence area of people was considered in urban or rural areas. The analysis was carried out using the Bayes Theorem and the results show that in the rural population the probability of contracting an infection of this kind is 8.41% whilst in the urban area the probability is 3.57%. These results show an urgent need to provide safe water sources to the population, as well as to instigate an environmental legislation reform that allows for controlling the release of emerging pollutants, including antibiotics.

Cytotoxicity and proliferative capacity impairment induced on human brain cell cultures after short- and long-term exposure to magnetite nanoparticles.

Since magnetic iron oxide nanoparticles (IONP) as magnetite (Fe3 O4 NPs) have potential applications in life sciences, industrial fields and biomedical care, the risks for occupational, general population and patients rises correspondingly. Excessive IONP accumulation in central nervous system (CNS) cells can lead to a disruption of normal iron metabolism/homeostasis, which is a characteristic hallmark resembling that of several neurodegenerative disorders. Fe3 O4 NPs- versus Fe3 O4 bulk-induced toxic effects have been assessed in two human CNS cells namely astrocytes (D384) and neurons (SH-SY5Y) after short-term exposure (4-24-48 h) to 1-100 µg ml-1 , and long-term exposure to lower concentrations. Short-term Fe3 O4 NPs induced significant concentration- and time-dependent alterations of mitochondrial function in D384 (25-75% cell viability decrease): effects started at 25 µg ml-1 after 4 h, and 1 µg ml-1 after 48 h. SH-SY5Y were less susceptible: cytotoxicity occurred after 48  h only with 35-45% mortality (10-100 µg ml-1 ). Accordingly, a more marked intracellular iron accumulation was observed in astrocytes than neurons. Membrane integrity was unaltered in both CNS cell types. Lowering Fe3 O4 NP concentrations (0.05-10 µg ml-1 ) and prolonging the exposure time (up to 10 days), D384 toxicity was again observed (colony number decrease at ≥0.05 µg ml-1 , morphology alterations and colony size reduction at ≥0.5 µg ml-1 ). Effects on SH-SY5Y appeared at the highest concentration only. Fe3 O4 bulk was always remarkably toxic toward both cells. In summary, human cultured astrocytes were susceptible to both Fe3 O4 NP and bulk forms following short-term and extended exposure to low concentrations, while neurons were more resistant to NPs. Cellular iron overload may trigger adverse responses by releasing iron ions (particularly in astrocytes) thus compromising the normal functions of CNS. Copyright © 2016 John Wiley & Sons, Ltd.

Toxicity Evaluation of Iron Oxide (Fe3O4) Nanoparticles on Human Neuroblastoma-Derived SH-SY5Y Cell Line.

Several studies suggest that Iron Oxide nanoparticles may arrive to central nervous system independently of the route of administration. Actually, evidences indicate that the presence iron oxide nanoparticles into nervous system are linked to several neurodegenerative diseases. In this regard, our goal was to assess in vitro PolyVinylPirrolidone coated Iron Oxide nanoparticles, diameter of 20 nm, neuro-toxicity and their mechanism of action, which was fixed over the human neuronal cell line SH-SY5Y. Inducted biological effects were evaluated after 4­48 hours at crescents doses 1­100 µg/mL using the following endpoints: (i) Membrane integrity: Nanoparticles have produced no effect over cellular membrane for every dose and time evaluated; (ii) Mitochondrial activity: Starting at 10 µg/mL with a decrease of cellular vitality of 35%, and a maximum decrease of 45% at highest dose (100 µg/mL); (iii) Cellular morphology: Cells have evidenced no alteration after 48 hours of exposure; (iv) Cellular uptake: Dose-time dependent accumulation has observed: blue spots have been found at 10 µg/mL and over. Concluding, mitochondria are apparently the target: considering that the toxic effect produced by PolyVinylPirrolidone coated Iron Oxide nanoparticles after 48 hours of exposure in a dose-time dependent manner was evident.