Changes in glucose uptake rate and in the energy status of PC-12 cells acutely exposed to hexavalent chromium,an established human carcinogen

In the 1920s, Otto Warburg reported a striking metabolic shift in solid tumors: contrary to their normal counter parts, which exhibited a nearly pure respiratory metabolism, where cancer cells relied strongly on lactic fermentation for energy production, even in the presence of ample oxygen. This metabolic shift, later named the Warburg effect, is now viewed as a nearly universal cancer phenotype. To investigate whether it is operating in hexavalent chromium (Cr(VI))-induced carcinogenesis, PC-12 cells were exposed to low Cr(VI) concentrations and effects determined on the rates of glucose uptake, lactate production and oxygen consumption, critical indicators of the type of energy metabolism adopted by the cells. Further, the influence on the cells’ energy charge, an important parameter in the evaluation of the cellular physiological state was assessed. In the presence of ample oxygen, concentration-dependent, statistically significant decreases in the energy charge were detected, which were accompanied by an increased glucose uptake rate. This enhanced uptake may constitute the first step in a compensatory mechanism aimed at counteracting the decrease in energy charge. Although these changes may be too small to exert an impact in the cellular functions, they may provide insight into the initial steps of Cr(VI)-induced carcinogenesis.     

Assessment of the in vivo genotoxicity of a new formulation of Bacillus thuringiensis var israelensis SH-14

Biological control agents have become a useful alternative for the reduction of the use of chemical insecticides. LABIOFAM (Cuba) is developing a new formulation of a biolarvicide that possesses as active biological agent Bacillus thuringiensis var israelensis serotype H14. In order to evaluate the genotoxicity of this new formulation, an in vivo battery test was used: micronucleus (MN), chromosome aberrations (CAs), and sperm morphology (SM) assays. A dose of 6.45?×?10⁸ spores was administered per animal via oral administration. Bone marrow cells were collected 24?h after a two day treatment for the MN assay, and 24?h after a unique treatment for the CA assay, using cyclophosphamide as the positive control. Sperm cells were collected at 5 weeks from the first of five administrations for the SM test, using acrylamide as positive control. Bacillus thuringiensis var israelensis serotype H14 failed to show either a significative increase of micronucleated polychromatic erythrocytes, chromosomal aberrations, or sperm abnormalities. Acute oral administration of a high dose of Bacillus thuringiensis var israelensis serotype H14 did not produce mutagenic effects in bone marrow or sperm cells.     

Occurrence of endocrine disruptor compounds in the estuary of the Iberian Douro River and nearby Porto Coast (NW Portugal)

Previous studies in the Douro River estuary, based on occasional sampling, showed the presence of several estrogenic disrupting chemicals (EDCs). In sequence, we hypothesized that such type of pollution was more likely an enduring issue than an occasional phenomenon, and that it may even affect recreational beaches in each side of the estuarine mouth. Thus to conclude about the continuous influx of EDCs, water samples were taken twice a day, once per a week, from March to May of 2009, at four sites within the estuary and at two sites in the coastline. After solid-phase extraction, the extracts were prepared for GC-MS analysis of 11 reference EDCs. These embraced natural and pharmaceutical estrogens (17β-estradiol, estrone and 17α-ethynylestradiol) and xenoestrogenic industrial pollutants (4-octylphenol, 4-nonylphenol, and their mono and diethoxylates and bisphenol A). Data showed the ubiquitous presence of potentially hazardous amounts of natural estrogens (particularly of estradiol, ca 5.5?ng?L^?1) and persistent organic pollutants such as nonylphenol mono (up to 550?ng?L^?1) and diethoxylate (up to 2000?ng?L^?1). It was concluded that the targeted area is continuously polluted by the assayed EDCs, and as a consequence, conditions exist for endocrine disturbance in the biota by chronic exposure to EDCs.     

Mitigation of glyphosate-based herbicide toxicity in maize (Zea mays L.) seedlings by ascorbic acid

Abstract

The toxicity of glyphosate at 3.6?mg L^?1 to maize seedlings raised from un-treated seeds and the effectiveness of seed pretreatment by soaking in 0.25?mmol L^?1 ascorbic acid (AsA) solution for mitigation of toxicity were evaluated in hydroponic culture. Glyphosate dramatically reduced the growth of roots and photosynthetic pigments in the leaves but increased protein content in the leaves. Superoxide dismutase activity and AsA concentration in the roots were increased, and guaiacol peroxidase (GPOX) activity was unaffected. Pretreatment with AsA improved the dry mass of the roots and shoots, increased the protein content in roots and leaves, and significantly decreased the activity of GPOX in roots. The positive effect of AsA treatment was not associated with more efficient functioning of the antioxidative system.     

Trends in precipitation chemistry in Alaska, 1980–1998

Nineteen years (1980–1998) of precipitation chemistry data from a site in Alaska are examined for trends using a least squares general linear model. The annual concentrations of SO^2– ₄ show a significant decreasing trend at 0.001 level and the annual change in concentration is —0.012mg 1^–1 yr^–1. The annual concentrations of NO ^– ₃ show an increasing tendency non‐significant. The annual base cation concentrations show a clear significant decreasing trend at 0.001 level and the decrease is —0.009mg 1^–1 yr^–1. Ca²⁺ concentrations exhibit a significant decreasing trend at 0.001 level and the annual change of concentration is —0.003 mg 1^–1 yr^–1. Mg²⁺ and Na⁺ concentrations show a significant decreasing trend at 0.01 level and the annual change is —0.001 mg1^–1 yr^–1 for Mg²⁺ and —0.004 mg1^–1 yr^–1 for Na⁺. K⁺ concentrations are characterised by a decreasing trend, significant at 0.05 level. K⁺ concentrations have decreased —0.002mg1^–1 yr^–1. The strongest rates of concentration decline for base cations, Ca²⁺, Mg²⁺, K⁺ and Na⁺ occurred in fall and winter season. The annual values of pH show a decreasing trend non‐significant. The values of pH oscillate between 5.1 and 5.6 during the period considered.     

Analysis of the ph in Europe during the period 1986–1997

The annual averages (1986–1997) of pH are analysed for the most important European Monitoring and Evaluation Programme stations in Europe. The first objective is to discover the different temporal patterns and trends for the pH. To do this, a cluster analysis is developed. The trends are analysed by linear regression for the annual averages. In general, the pH shows an increasing trend significant at 0.05 level and the annual change ranging from +0.01 to +0.05 pH‐units per year for the different clusters obtained. The second objective is to examine the spatial variability of pH in precipitation through the use of principal component analysis. Six statistically significant modes of variability are obtained for the pH which represent the 84.5% of the total variance.     

The role of environmental activity integration into the R&D department to obtain competitive advantage

The objective of this work is to examine to what degree the integration between R&D and environmental departments facilitates the achievement of an environmental practice-derived competitive advantage. With this aim, we surveyed 110 International Organization for Standardization (ISO) 14001 certified factories. The results reveal that the integration of environmental action into the R&D department enhances a company's reputation through the product quality and image. Moreover, the said integration positively influences the company's overall innovative capability and, hence, its ability to penetrate international markets.     

An approach to simulate wind fields around an urban environment for wind energy application

This work proposes an approach to simulate wind flow fields around an urban environment with the aim of evaluating the potential impact of buildings on the general wind patterns and power production using the current generation of commercial wind turbines. The simulation process was performed with the aid of accessible computational tools that can potentially render the proposed procedure applicable in other cases of interest. The roughness of the urban environment was defined as the association of roughness map, topography, and an alternative process for obtaining the volumetry of buildings. A case study was conducted in a region located at the district of Boa Viagem (Recife-PE) for assessing the applicability of the approach. Scenarios were designed in order to simulate wind flow patterns and pre-identify sites that have suitable wind energy potential for electric power production by investigating the combination of wind speed magnitude and turbulence intensity. From the results obtained, it was possible to identify zones of potential wind sources that are not detected in classical wind atlas probably due to the influence of the built environment on local wind flow patterns.