Treatment of Domestic Sewage in an Anaerobic-Aerobic Fixed-bed Reactor with Recirculation of the Liquid Phase

This study reports the performance of a combined anaerobic-aerobic packed-bed reactor that can be used to treat domestic sewage. Initially, a bench-scale reactor was operated in three experimental phases. In the first phase, the anaerobic reactor was operated with an average organic matter removal efficiency of 77% for a hydraulic retention time (HRT) of 10 h. In the second phase, the reactor was operated with an anaerobic stage followed by an aerobic zone, resulting in a mean value of 91% efficiency. In the third and final phase, the anaerobic-aerobic reactor was operated with recirculation of the effluent of the reactor through the anaerobic zone. The system yielded mean total nitrogen removal percentages of 65 and 75% for recycle ratios (r) of 0.5 and 1.5, respectively, and the chemical oxygen demand (COD) removal efficiencies were higher than 90%. When the pilot-scale reactor was operated with an HRT of 12 h and r values of 1.5 and 3.0, its performance was similar to that observed in the bench-scale unit (92% COD removal for r = 3.0). However, the nitrogen removal was lower (55% N removal for r = 3.0) due to problems with the hydrodynamics in the aerobic zone. The anaerobic-aerobic fixed-bed reactor with recirculation of the liquid phase allows for concomitant carbon and nitrogen removal without adding an exogenous source of electron donors and without requiring any additional alkalinity supplementation.

DNA damage profiles induced by sunlight at different latitudes

Despite growing knowledge on the biological effects of ultraviolet (UV) radiation on human health and ecosystems, it is still difficult to predict the negative impacts of the increasing incidence of solar UV radiation in a scenario of global warming and climate changes. Hence, the development and application of DNA-based biological sensors to monitor the solar UV radiation under different environmental conditions is of increasing importance. With a mind to rendering a molecular view-point of the genotoxic impact of sunlight, field experiments were undertaken with a DNA-dosimeter system in parallel with physical photometry of solar UVB/UVA radiation, at various latitudes in South America. Onapplying biochemical and immunological approaches based on specific DNA-repair enzymes and antibodies, for evaluating sunlight-induced DNA damage profiles, it became clear that the genotoxic potential of sunlight does indeed vary according to latitude. Notwithstanding, while induction of oxidized DNA bases is directly dependent on an increase in latitude, the generation of 6-4PPs is inversely so, whereby the latter can be regarded as a biomolecular marker of UVB incidence. This molecular DNA lesion-pattern largely reflects the relative incidence of UVA and UVB energy at any specific latitude. Hereby is demonstrated the applicability of this DNA-based biosensor for additional, continuous field experiments, as a means of registering variations in the genotoxic impact of solar UV radiation. Environ. Mol. Mutagen. 2012. (c) 2012 Wiley Periodicals, Inc.

Influence diagnostics in Gaussian spatial linear models

Spatial linear models have been applied in numerous fields such as agriculture, geoscience and environmental sciences, among many others. Spatial dependence structure modelling, using a geostatistical approach, is an indispensable tool to estimate the parameters that define this structure. However, this estimation may be greatly affected by the presence of atypical observations in the sampled data. The purpose of this paper is to use diagnostic techniques to assess the sensitivity of the maximum-likelihood estimators, covariance functions and linear predictor to small perturbations in the data and/or the spatial linear model assumptions. The methodology is illustrated with two real data sets. The results allowed us to conclude that the presence of atypical values in the sample data have a strong influence on thematic maps, changing the spatial dependence structure.

Air pollution and health: bridging the gap from sources to health outcomes: conference summary

Air Pollution and Health: Bridging the Gap from Sources to Health Outcomes, an international specialty conference sponsored by the American Association for Aerosol Research, was held to address key uncertainties in our understanding of adverse health effects related to air pollution and to integrate and disseminate results from recent scientific studies that cut across a range of air pollution-related disciplines. The Conference addressed the science of air pollution and health within a multipollutant framework (herein "multipollutant" refers to gases and particulate matter mass, components, and physical properties), focusing on five key science areas: sources, atmospheric sciences, exposure, dose, and health effects. Eight key policy-relevant science questions integrated across various parts of the five science areas and a ninth question regarding findings that provide policy-relevant insights served as the framework for the meeting. Results synthesized from this Conference provide new evidence, reaffirm past findings, and offer guidance for future research efforts that will continue to incrementally advance the science required for reducing uncertainties in linking sources, air pollutants, human exposure, and health effects. This paper summarizes the Conference findings organized around the science questions. A number of key points emerged from the Conference findings. First, there is a need for greater focus on multipollutant science and management approaches that include more direct studies of the mixture of pollutants from sources with an emphasis on health studies at ambient concentrations. Further, a number of research groups reaffirmed a need for better understanding of biological mechanisms and apparent associations of various health effects with components of particulate matter (PM), such as elemental carbon, certain organic species, ultrafine particles, and certain trace elements such as Ni, V, and Fe(II), as well as some gaseous pollutants. Although much debate continues in this area, generation of reactive oxygen species induced by these and other species present in air pollution and the resulting oxidative stress and inflammation were reiterated as key pathways leading to respiratory and cardiovascular outcomes. The Conference also underscored significant advances in understanding the susceptibility of populations, including the role of genetics and epigenetics and the influence of socioeconomic and other confounding factors and their synergistic interactions with air pollutants. Participants also pointed out that short-and long-term intervention episodes that reduce pollution from sources and improve air quality continue to indicate that when pollution decreases so do reported adverse health effects. In the limited number of cases where specific sources or PM2.5 species were included in investigations, specific species are often associated with the decrease in effects. Other recent advances for improved exposure estimates for epidemiological studies included using new technologies such as microsensors combined with cell phone and integrated into real-time communications, hybrid air quality modeling such as combined receptor-and emission-based models, and surface observations used with remote sensing such as satellite data.

ENVIRONMENTAL TOBACCO SMOKE INDUCES OXIDATIVE STRESS IN DISTINCT BRAIN REGIONS OF INFANT MICE

Environmental tobacco smoke (ETS) leads to the death of 600,000 nonsmokers annually and is associated with disturbances in antioxidant enzyme capacity in the adult rodent brain. However, little is known regarding the influence of ETS on brain development. The aim of this study was to determine levels of malonaldehyde (MDA) and 3-nitrotyrosine (3-NT), as well as enzymatic antioxidant activities of glutathione peroxidase (GPx), glutathione reductase (GR), glutathione S-transferase (GST), and superoxide dismutase (SOD), in distinct brain structures. BALB/c mice were exposed to ETS twice daily for 1 h from postnatal day 5 through postnatal day 18. Acute exposure was performed for 1 h on postnatal day 18. Mice were euthanized either immediately (0) or 3 h after the last exposure. Immediately after an acute exposure there were higher GR and GST activities and MDA levels in the hippocampus, higher GPx and SOD activities in the prefrontal cortex, and higher GST activity and MDA levels in the striatum and cerebellum. Three hours later there was an increase in SOD activity and MDA levels in the hippocampus and a decrease in the activity of all enzymes in the prefrontal cortex. Immediately after final repeated exposure there were elevated levels of GST and GR activity and decreased GPx activity in the hippocampus. Moreover, a rise was found in GPx and GST activities in the prefrontal cortex and increased GST and GPx activity in the striatum and cerebellum, respectively. After 3 h the prefrontal cortex showed elevated GR and GST activities, and the striatum displayed enhanced GST activity. Data showed that enzymatic antioxidant system in the central nervous system responds to ETS differently in different regions of the brain and that a form of adaptation occurs after several days of exposure.

Multi-molecular markers and metals as tracers of organic matter inputs and contamination status from an Environmental Protection Area in the SW Atlantic (Laranjeiras Bay, Brazil)

The sources and concentrations of aliphatic hydrocarbons (AHs) and polycyclic aromatic hydrocarbons (PAHs), faecal and biogenic sterols, and trace metals at 10 sampling sites located in Laranjeiras Bay, a large Environmental Protection Area in the southern Atlantic region of Brazil, were determined to assess the sources of organic matter and the contamination status of estuarine sediments. Organic compounds were determined by GC-FID and GC-MS, and ICP-OES was used to evaluate trace metals. The total AHs concentration ranged from 0.28 to 8.19 mu g g(-1), and n-C-29 and n-C-31 alkanes were predominant, indicating significant inputs from higher terrestrial plants. Unresolved complex mixtures (UCM) were not detected at any site, suggesting that the study area was not significantly contaminated by fossil fuels. The total PAH concentration varied from 3.85 to 89.2 ng g(-1). The ratio between selected PAH isomers showed that combustion of biomass, coal, and petroleum is the rnain source of PAHs in the study area. The concentrations of the faecal sterols coprostanol and epicoprostanol were below the detection limits, suggesting that sewage was not a significant contributor to sedimentary organic matter. The concentrations of the trace metals (As, Cr, Cu, Ni, Pb and Zn) were low, except near sites located at the mouths of rivers that discharge into the study area and near urbanised regions (Paranagua city and the adjoining harbour). In general, the concentrations of PAHs were below the threshold effect concentrations (TEL) levels. Although the As, Cr and Ni concentrations were above the TEL levels, the study area can be considered as preserved from human activities.

Determination of atenolol in environmental water samples and pharmaceutical formulations at a graphite-epoxy composite electrode

A bare graphite-epoxy composite was evaluated as an electrode material in the determination of atenolol in natural water samples and pharmaceutical formulations for which the analyte was spiked. Using a DPV procedure, a linear response was observed in the 4.45-84.7 mu mol L-1 range with a LOD = 2.23 mu mol L-1, without need of surface renewal between successive runs, and recoveries between 92.5 and 107.5% for pharmaceutical formulations. The results obtained from the proposed procedure agreed with HPLC results within a 95% confidence level. During the determination of atenolol in water samples, recoveries between 96.1 and 102.6% were found.

Phylogeography of an Atlantic forest passerine reveals demographic stability through the last glacial maximum

In this study we analyzed the phylogeographic pattern and historical demography of an endemic Atlantic forest (AF) bird, Basileuterus leucoblepharus, and test the influence of the last glacial maximum (LGM) on its population effective size using coalescent simulations. We address two main questions: (i) Does B. leucoblepharus present population genetic structure congruent with the patterns observed for other AF organisms? (ii) How did the LGM affect the effective population size of B. leucoblepharus? We sequenced 914 bp of the mitochondrial gene cytochrome b and 512 bp of the nuclear intron 5 of beta-fibrinogen of 62 individuals from 15 localities along the AF. Both molecular markers revealed no genetic structure in B. leucoblepharus. Neutrality tests based on both loci showed significant demographic expansion. The extended Bayesian skyline plot showed that the species seems to have experienced demographic expansion starting around 300,000 years ago, during the late Pleistocene. This date does not coincide with the LGM and the dynamics of population size showed stability during the LGM. To further test the effect of the LGM on this species, we simulated seven demographic scenarios to explore whether populations suffered specific bottlenecks. The scenarios most congruent with our data were population stability during the LGM with bottlenecks older than this period. This is the first example of an AF organism that does not show phylogeographic breaks caused by vicariant events associated to climate change and geotectonic activities in the Quaternary. Differential ecological, environmental tolerances and habitat requirements are possibly influencing the different evolutionary histories of these organisms. Our results show that the history of organism diversification in this megadiverse Neotropical forest is complex. Crown Copyright (c) 2012 Published by Elsevier Inc. All rights reserved.

Segmental dataset and whole body expression data do not support the hypothesis that non-random movement is an intrinsic property of Drosophila retrogenes

Background: Several studies in Drosophila have shown excessive movement of retrogenes from the X chromosome to autosomes, and that these genes are frequently expressed in the testis. This phenomenon has led to several hypotheses invoking natural selection as the process driving male-biased genes to the autosomes. Metta and Schlotterer (BMC Evol Biol 2010, 10:114) analyzed a set of retrogenes where the parental gene has been subsequently lost. They assumed that this class of retrogenes replaced the ancestral functions of the parental gene, and reported that these retrogenes, although mostly originating from movement out of the X chromosome, showed female-biased or unbiased expression. These observations led the authors to suggest that selective forces (such as meiotic sex chromosome inactivation and sexual antagonism) were not responsible for the observed pattern of retrogene movement out of the X chromosome. Results: We reanalyzed the dataset published by Metta and Schlotterer and found several issues that led us to a different conclusion. In particular, Metta and Schlotterer used a dataset combined with expression data in which significant sex-biased expression is not detectable. First, the authors used a segmental dataset where the genes selected for analysis were less testis-biased in expression than those that were excluded from the study. Second, sex-biased expression was defined by comparing male and female whole-body data and not the expression of these genes in gonadal tissues. This approach significantly reduces the probability of detecting sex-biased expressed genes, which explains why the vast majority of the genes analyzed (parental and retrogenes) were equally expressed in both males and females. Third, the female-biased expression observed by Metta and Schltterer is mostly found for parental genes located on the X chromosome, which is known to be enriched with genes with female-biased expression. Fourth, using additional gonad expression data, we found that autosomal genes analyzed by Metta and Schlotterer are less up regulated in ovaries and have higher chance to be expressed in meiotic cells of spermatogenesis when compared to X-linked genes. Conclusions: The criteria used to select retrogenes and the sex-biased expression data based on whole adult flies generated a segmental dataset of female-biased and unbiased expressed genes that was unable to detect the higher propensity of autosomal retrogenes to be expressed in males. Thus, there is no support for the authors' view that the movement of new retrogenes, which originated from X-linked parental genes, was not driven by selection. Therefore, selection-based genetic models remain the most parsimonious explanations for the observed chromosomal distribution of retrogenes.

From Amazonia to the Atlantic forest: Molecular phylogeny of Phyzelaphryninae frogs reveals unexpected diversity and a striking biogeographic pattern emphasizing conservation challenges

Documenting the Neotropical amphibian diversity has become a major challenge facing the threat of global climate change and the pace of environmental alteration. Recent molecular phylogenetic studies have revealed that the actual number of species in South American tropical forests is largely underestimated, but also that many lineages are millions of years old. The genera Phyzelaphryne (1 sp.) and Adelophryne (6 spp.), which compose the subfamily Phyzelaphryninae, include poorly documented, secretive, and minute frogs with an unusual distribution pattern that encompasses the biotic disjunction between Amazonia and the Atlantic forest. We generated >5.8 kb sequence data from six markers for all seven nominal species of the subfamily as well as for newly discovered populations in order to (1) test the monophyly of Phyzelaphryninae, Adelophryne and Phyzelaphryne, (2) estimate species diversity within the subfamily, and (3) investigate their historical biogeography and diversification. Phylogenetic reconstruction confirmed the monophyly of each group and revealed deep subdivisions within Adelophryne and Phyzelaphryne, with three major clades in Adelophryne located in northern Amazonia, northern Atlantic forest and southern Atlantic forest. Our results suggest that the actual number of species in Phyzelaphryninae is, at least, twice the currently recognized species diversity, with almost every geographically isolated population representing an anciently divergent candidate species. Such results highlight the challenges for conservation, especially in the northern Atlantic forest where it is still degraded at a fast pace. Molecular dating revealed that Phyzelaphryninae originated in Amazonia and dispersed during early Miocene to the Atlantic forest. The two Atlantic forest clades of Adelophryne started to diversify some 7 Ma minimum, while the northern Amazonian Adelophryne diversified much earlier, some 13 Ma minimum. This striking biogeographic pattern coincides with major events that have shaped the face of the South American continent, as we know it today. (C) 2012 Elsevier Inc. All rights reserved.

Abundance of biofilm on intertidal rocky shores: Can trampling by humans be a negative influence?

Trampling by human visitors to rocky shores is a known stressor on macroorganisms. However, the effects of trampling on rocky intertidal biofilm, a complex association of microorganisms of ecological importance in coastal communities, have not been quantified. We evaluated the impact of trampling frequency and intensity on total biomass of epilithic microalgae on intertidal rocky shores in the southeast of Brazil. There was a trend of increase in the variability of biomass of biofilm in function of intensity of trampling, but no significant effects emerged among trampling treatments. The low influence of trampling on biofilm might be a result of the small dimensions of the organisms coupled with their natural resilience and roughness of the substrate; the former preventing the removal of biofilm layers by shoes and facilitating their quick recovery. Our results provide insights for management and conservation of coastal ecosystems revealing a weaker impact of trampling on biofilm than that reported on macroorganisms. (C) 2012 Elsevier Ltd. All rights reserved.

Survival and movements of Magellanic penguins rehabilitated from oil fouling along the coast of South America, 2000-2010

Oil pollution is a significant conservation concern. We examined data from six institutions along the coast of South America: Emergency Relief Team of the International Fund for Animal Welfare, Fundacion Mundo Marino, Centro de Recuperacao de Animais Marinhos, Natura Patagonia, Associacao R3 Animal, and Mar del Plata Aquarium and data from resightings in Argentina, Brazil, Chile and Falkland/Malvinas Islands. From 2000 to 2010, 2183 oiled Magellanic penguins were rehabilitated as part of the routine activities of these institutions or during emergency responses to eight oil spills in which they were involved; all rehabilitated penguins were flipper banded and released. Since their release, 41 penguins were resighted until 31 December 2011. The results demonstrate that, when combined with other prevention strategies, the rehabilitation of Magellanic penguins is a strategy that contributes to the mitigation of adverse effects of oil spills and chronic pollution to the species. (C) 2012 Elsevier Ltd. All rights reserved.

Associations of Forest Cover, Fragment Area, and Connectivity with Neotropical Understory Bird Species Richness and Abundance

Theoretical and empirical studies demonstrate that the total amount of forest and the size and connectivity of fragments have nonlinear effects on species survival. We tested how habitat amount and configuration affect understory bird species richness and abundance. We used mist nets (almost 34,000 net hours) to sample birds in 53 Atlantic Forest fragments in southeastern Brazil. Fragments were distributed among 3 10,800-ha landscapes. The remaining forest in these landscapes was below (10% forest cover), similar to (30%), and above (50%) the theoretical fragmentation threshold (approximately 30%) below which the effects of fragmentation should be intensified. Species-richness estimates were significantly higher (F = 3715, p = 0.00) where 50% of the forest remained, which suggests a species occurrence threshold of 30-50% forest, which is higher than usually occurs (<30%). Relations between forest cover and species richness differed depending on species sensitivity to forest conversion and fragmentation. For less sensitive species, species richness decreased as forest cover increased, whereas for highly sensitive species the opposite occurred. For sensitive species, species richness and the amount of forest cover were positively related, particularly when forest cover was 30-50%. Fragment size and connectivity were related to species richness and abundance in all landscapes, not just below the 30% threshold. Where 10% of the forest remained, fragment size was more related to species richness and abundance than connectivity. However, the relation between connectivity and species richness and abundance was stronger where 30% of the landscape was forested. Where 50% of the landscape was forested, fragment size and connectivity were both related to species richness and abundance. Our results demonstrated a rapid loss of species at relatively high levels of forest cover (30-50%). Highly sensitive species were 3-4 times more common above the 30-50% threshold than below it; however, our results do not support a unique fragmentation threshold.

Xylella fastidiosa comparative genomic database is an information resource to explore the annotation, genomic features, and biology of different strains

The Xylella fastidiosa comparative genomic database is a scientific resource with the aim to provide a user-friendly interface for accessing high-quality manually curated genomic annotation and comparative sequence analysis, as well as for identifying and mapping prophage-like elements, a marked feature of Xylella genomes. Here we describe a database and tools for exploring the biology of this important plant pathogen. The hallmarks of this database are the high quality genomic annotation, the functional and comparative genomic analysis and the identification and mapping of prophage-like elements. It is available from web site http://www.xylella.lncc.br.

Bixin and norbixin protect against DNA-damage and alterations of redox status induced by methylmercury exposure in vivo

Populations in the Amazon are exposed to organic mercury via consumption of contaminated foods. These ethnic groups consume a specific plant seed annatto which contains certain carotenoids. The aim of this study was to find out if these compounds (bixin, BIX and norbixin, NOR), protect against DNA-damage caused by the metal. Therefore, rats were treated orally with methylmercury (MeHg) and with the carotenoids under conditions that are relevant to humans. The animals were treated either with MeHg (30 mu g/kg/bw/day), BIX (0.110 mg/kg/bw/day), NOR (0.011.0 mg/kg/bw/day) or combinations of the metal compound and the carotenoids consecutively for 45 days. Subsequently, the glutathione levels (GSH) and the activity of catalase were determined, and DNA-damage was measured in hepatocytes and leukocytes using single cell gel electrophoresis assays. Treatment with the metal alone caused a decrease in the GSH levels (35%) and induced DNA damage, which resulted in increased DNA migration after electrophoresis in liver and blood cells, whereas no effects were seen with the carotenoids alone. When BIX or NOR were given in combination with organic mercury, the intermediate and the highest concentrations of the carotenoids (1.0 and 10.0 mg/kg/bw/day BIX and 0.1 and 1.0 mg/kg/bw/day NOR) protected against DNA-damage. Furthermore, we found with both carotenoids, a moderate increase in the GSH levels in both metal-treated and untreated animals, while the activities of catalase remained unchanged. Our results indicate that consumption of BIX and NOR may protect humans against the adverse health effects caused by exposure to organic mercury. Environ. Mol. Mutagen., 2012. (c) 2012 Wiley Periodicals, Inc.