- Metal oxyanion removal from wastewater using manganese-oxidizing aerobic granular sludge. [Journal Article]
- CChemosphere 2019 Jul 11; 236:124353
- As, Sb, and Cr are redox-sensitive and toxic heavy metal(loid)s, and redox reactions are usually involved in the treatment of substrates containing these elements. In this study, manganese-oxidizing …
As, Sb, and Cr are redox-sensitive and toxic heavy metal(loid)s, and redox reactions are usually involved in the treatment of substrates containing these elements. In this study, manganese-oxidizing aerobic granular sludge (Mn-AGS) was obtained by continuously adding Mn(II) to the sludge in a sequencing batch reactor (SBR). Morphological observations, and analyses of extracellular polymeric substances (EPS), Mn valence-states, and microbial communities were performed on the resulting sludge. After 50 days of cultivation, biogenic Mn(III,IV) oxides (bio-MnOx) accumulated up to approximately 25 mg Mn/g suspended solids (SS). X-ray photoelectron spectroscopy (XPS) revealed that the percentage of Mn(III,IV) was 87.6%. The protein (PN) component in EPS increased from 80.3 to 87.8 mg/g volatile suspended solids (VSS) during cultivation, which might be favorable for sludge granulation and heavy metal(loid) removal. Batch experiments showed that Mn-AGS was better at oxidizing As(III)/Sb(III) into less toxic As(V)/Sb(V) than traditional AGS. Remarkably, the results indicated that Mn-AGS did not oxidize Cr(III) but was able to reduce Cr(VI) into relatively harmless Cr(III). This work provided a new promising method with which to treat As(III), Sb(III), and Cr(VI) in wastewaters.
- Acute and chronic effects of perfluoroalkyl substance mixtures on larval American bullfrogs (Rana catesbeiana). [Journal Article]
- CChemosphere 2019 Jul 10; 236:124350
- Discovery of elevated concentrations of perfluoroalkyl substances (PFAS) in ground and surface waters globally has heightened concern over their potential adverse health effects. The effects of PFAS …
Discovery of elevated concentrations of perfluoroalkyl substances (PFAS) in ground and surface waters globally has heightened concern over their potential adverse health effects. The effects of PFAS are known largely from acute toxicity studies of single PFAS compounds in model organisms, while little is understood concerning effects of mixtures on wildlife. To address this gap, we examined the acute and chronic effects of two of the most common PFAS (perfluorooctanesulfonic acid [PFOS] and perfluorooctanoic acid [PFOA]) and their mixtures on survival, growth, and development of American bullfrog (Rana catesbeiana) tadpoles. In 96 h acute toxicity tests, PFOS was 10X more toxic than PFOA and effects of the two chemicals in combination appeared additive. The effects of PFOS, PFOA, and their interaction varied by the sublethal endpoint under consideration in a 72 d exposure. Effects of PFAS on tadpole mass and developmental stage were largely driven by PFOS and there was no evidence of interactions suggesting deviations from additivity. However, for snout-vent length, reductions in length in mixture treatments were greater than expected based on the effects of the two chemicals independently (i.e. non-additivity). Further, effects on snout-vent length in single chemical exposures were only observed with PFOA. Our results highlight the importance of assessing combined effects of PFAS co-occurring in the environment and suggest caution in extrapolating the effects of acute toxicity studies to more environmentally relevant exposures. Future studies examining effects of environmentally relevant mixtures on wildlife will be essential for effective environmental risk assessment and management.
- Climate change effects on population dynamics of three species of Amazonian lizards. [Journal Article]
- CBComp Biochem Physiol A Mol Integr Physiol 2019 Jul 15; :110530
- The scarcity of data on natural history and ecology of lizards still limits the understanding of population dynamics for many species. We attempt to evaluate possible effects of climate change on the…
The scarcity of data on natural history and ecology of lizards still limits the understanding of population dynamics for many species. We attempt to evaluate possible effects of climate change on the population dynamics of three lizard species (Ameiva ameiva, Gonatodes humeralis and Norops fuscoauratus) in two Amazonian localities (Caxiuanã National Forest and Ducke Reserve). We calculated a tolerance index combining environmental thermal adequacy with the b-d model, which consider survival and reproductive rates to calculate population dynamics. Thus, we simulated population growth rates based on current and future environmental operative temperatures, considering an optimistic and a business-as-usual scenario of greenhouse gases emissions (GGE), and evaluate if the sensitivity of life history traits to population growth rate are likely to be trigged by climate change. Our results demonstrated that both populations of G. humeralis and the Ducke population of N. fuscoauratus may become locally extinct under both scenarios of GGE, while both populations of A. ameiva are likely to decrease, but without reaching a scenario of local extirpation. This study represents the first effort to evaluate the sensitivity of lizard populations and elasticity to climate change and demonstrate the geographic variability of these traits in three widespread and habitat-generalist species. We highlight the need of new studies focusing on species with different biological trait patterns, such as endemic distributions and habitat-specialists, to provide the theoretical and empirical basis for biologically informed conservation strategies and actions, in order to minimize the potential extinction of populations due to climate change.
- Indirect effects in a planktonic disease system. [Journal Article]
- TPTheor Popul Biol 2019 Jul 15
- Indirect effects, both density- and trait-mediated, have been known to act in tandem with direct effects in the interactions of numerous species. They have been shown to affect populations embedded i…
Indirect effects, both density- and trait-mediated, have been known to act in tandem with direct effects in the interactions of numerous species. They have been shown to affect populations embedded in competitive and mutualistic networks alike. In this work, we introduce a four-dimensional system of ordinary differential equations and investigate the interplay between direct density-effects and density- and trait-mediated indirect effects that take place in a yeast parasite-zooplankton host-incompetent competitor system embedded in a food web which also includes resources and predators. Among our main findings is the demonstration that indirect effects cause qualitative and quantitative changes almost indistinguishable from direct effects and the corroboration through our analysis of the fact that the effects of direct and indirect mechanisms cannot be disentangled. Our results underpin the conclusions of past studies calling for comprehensive models that incorporate both direct and indirect effects to better describe field data.
- Fatty acid content and profile of the novel strain of Coccomyxa elongata (Trebouxiophyceae, Chlorophyta) cultivated at reduced nitrogen and phosphorus concentrations. [Journal Article]
- JPJ Phycol 2019 Jul 18
- A novel freshwater strain of Coccomyxa elongata (MZ-Ch64) was isolated from the Zaporizhia region, Ukraine. The identification is based on the phylogenetic analysis of SSU rDNA gene and ITS1-5.8S rDN…
A novel freshwater strain of Coccomyxa elongata (MZ-Ch64) was isolated from the Zaporizhia region, Ukraine. The identification is based on the phylogenetic analysis of SSU rDNA gene and ITS1-5.8S rDNA-ITS2 region and predicted secondary structure of the ITS2. Phylogenetic analysis places this strain in the Coccomyxa group, within the class Trebouxiophyceae. The novel strain MZ-Ch64 formed a strongly supported lineage closest with C. elongata. The MZ-Ch64 strain differed from the morphological description of the species by the size of vegetative cells and absence of small mucilaginous caps at one end of the cell. A number of experiments with different concentrations of phosphate and nitrate were conducted to evaluate changes in the resulting fatty acid profiles and biomass productivity. The fatty acid profile and total fatty acids varied significantly under different nutrient deficiencies. The dominant fatty acid during cultivation on standard BBM medium, as well as in phosphorus-depleted conditions, was oleic acid (to 48.0-54.6% of total fatty acids). Absence of nitrogen alone, and absence of both nitrogen and phosphorus, led to an increase of palmitic acid (to 24.7-25.6%), cis-7-hexadecenoic acid (to 14.8%) and α-linolenic acid (to 9.1-10.1%) in comparison with the control sample. The greatest variation was found for oleic acid (31.9-54.6%). Thus, this strain can be considered as a potential producer of oleic acid or cis-7-hexadecenoic and α-linolenic acids for biotechnological applications. This article is protected by copyright. All rights reserved.
- Effects of single and repeated drought on soil microarthropods in a semi-arid ecosystem depend more on timing and duration than drought severity. [Journal Article]
- PlosPLoS One 2019; 14(7):e0219975
- Soil moisture is one of the most important factors affecting soil biota. In arid and semi-arid ecosystems, soil mesofauna is adapted to temporary drought events, but, until now, we have had a limited…
Soil moisture is one of the most important factors affecting soil biota. In arid and semi-arid ecosystems, soil mesofauna is adapted to temporary drought events, but, until now, we have had a limited understanding of the impacts of the different magnitudes and frequencies of drought predicted to occur according to future climate change scenarios. The present study focuses on how springtails and mites respond to simulated repeated drought events of different magnitudes in a field experiment in a Hungarian semi-arid sand steppe. Changes in soil arthropod activities were monitored with soil trapping over two years in a sandy soil. In the first year (2014), we applied an extreme drought pretreatment, and in the consecutive year, we applied less devastating treatments (severe drought, moderate drought, water addition) to these sites. In the first year, the extreme drought pretreatment tended to have a negative effect (either significantly or not significantly) on the capture of all Collembola groups, whereas all mite groups increased in activity density. However, in the consecutive year, between the extreme drought and control treatments, we only detected differences in soil microbial biomass. In the cases of severe drought, moderate drought and water addition, we did not find considerable changes across the microarthropods, except in the case of epedaphic Collembola. In the cases of the water addition and drought treatments, the duration and timing of the manipulation seemed to be more important for soil mesofauna than their severity (i.e., the level of soil moisture decrease). We suggest that in these extreme habitats, soil mesofauna are able to survive extreme conditions, and their populations recover rapidly, but they may not be able to cope with very long drought periods.
- A case of silent invasion: Citizen science confirms the presence of Harmonia axyridis (Coleoptera, Coccinellidae) in Central America. [Journal Article]
- PlosPLoS One 2019; 14(7):e0220082
- Harmonia axyridis (Coleoptera, Coccinellidae) is a globally invasive ladybird. It has been intentionally introduced in many countries as a biological control agent, whereas it has been unintentionall…
Harmonia axyridis (Coleoptera, Coccinellidae) is a globally invasive ladybird. It has been intentionally introduced in many countries as a biological control agent, whereas it has been unintentionally released in many others. Climatic factors are important in limiting the spread of H. axyridis. For example, very few records are known from tropical or desert regions. Currently, no published reports are known from Central America. Here, we report H. axyridis from Costa Rica, Guatemala, Honduras, Panama, and Puerto Rico. Specimens were either observed by the authors, discovered in dried insect collections, or retrieved from searching through online photographs available from the citizen science project iNaturalist and the photo-sharing website Flickr. These new records and the wide distribution of H. axyridis in Latin America suggest several invasion events, which have gone unnoticed until now. We stress the need for further, large-scale monitoring and show the advantage of citizen science to assess the presence of invasive alien species.
- Impact of plant growth regulators and soil properties on Miscanthus x giganteus biomass parameters and uptake of metals in military soils. [Journal Article]
- RERev Environ Health 2019 Jul 18
- The impact of plant growth regulators (PGRs) "Stimpo" and "Regoplant" on Miscanthus x giganteus (Mxg) biomass parameters was investigated when the plant was grown in military soils with different pro…
The impact of plant growth regulators (PGRs) "Stimpo" and "Regoplant" on Miscanthus x giganteus (Mxg) biomass parameters was investigated when the plant was grown in military soils with different properties from Dolyna, Ukraine and Hradcany, Czech Republic. The results showed that PGRs positively influenced the biomass parameters when the plant was grown in soil in Dolyna with good agricultural characteristics, the influence of "Regoplant" was higher and the best results were obtained with combined treatment: application to rhizomes before planting and spraying on the biomass during vegetation. Using of PGRs did not improve the biomass parameters when the plant was grown in poor soil in Hradcany. In parallel the peculiarities of the metals uptake process were studied for the following metals: chromium (Cr), manganese (Mn), nickel (Ni), copper (Cu), zinc (Zn), strontium (Sr) and lead (Pb). The uptake behavior of the monitored elements differed based on the soil quality. According to the bioconcentration factor uptake of the abiogenic elements, Cr and Pb, was dominant in the plant roots in both soils, whereas Ni was not detected in any plant tissues. The behavior of biogenic elements (Mn, Cu, Zn) and their analogs (Sr) was different. Those elements were more intensively taken up in shoot tissues in low-nutrient sandy Hradcany soils, while they were mainly taken up in plant roots in fertile Dolyna soils. The unusual behavior of biogenic elements in the low-nutrient soils may be explained by the effect of stress. However, more research is needed focused mainly on soil properties and nutrient availability in order to confirm or disprove this hypothesis and to explore the cause of the stress. The summarized results here show that soil properties influenced Mxg biomass parameters, affected the uptake behavior of metals significantly and tested PGRs cannot be utilized universally in the production of Mxg in the poor military soils.
- 100% Fruit Juice in Child and Adolescent Dietary Patterns. [Journal Article]
- JAJ Am Coll Nutr 2019 Jul 18; :1-6
- Objective: Nutritional advice based on strengthening the dietary pattern offers a very different perspective from the reductionist practice of reporting risks or benefits for individual foods. Metho…
Objective: Nutritional advice based on strengthening the dietary pattern offers a very different perspective from the reductionist practice of reporting risks or benefits for individual foods. Methods: A healthful dietary pattern can be composed of innumerable different combinations of foods and beverages that collectively and synergistically protect health. Although pure juices lack fiber, juicing retains the majority of health-promoting nutrients and phytochemicals of the whole fruit. Bioactive components of 100% fruit juice have demonstrated positive clinical effects on oxidative markers, inflammation, endothelial reactivity, lipid profiles, hypertension, and platelet aggregation. Fruit juice consumers have higher scores for diet quality. They consume more whole fruit, less added sugar, and greater amounts of vitamin C, magnesium, potassium, and fiber-containing foods than non-consumers. Results: Concerns that 100% fruit juice may be associated with childhood weight gain or metabolic consequences have not been supported by recent systematic reviews and meta-analyses. Juice consumption may be particularly important for the diet quality of lower-socioeconomic-status populations. Over the past 3 decades, as fruit juice intake has fallen substantially, the vacuum has not been filled by a comparable increase in servings of whole fruit, keeping Americans from meeting daily fruit recommendations. Conclusions: Counseling about individual foods without considering their impact on overall diet quality may harm the dietary pattern without discernible health benefits.
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- Protein deprivation facilitates the independent evolution of behavior and morphology. [Journal Article]
- EEvolution 2019 Jul 18
- Ecological conditions such as nutrition can change genetic covariances between traits and accelerate or slow down trait evolution. Since adaptive trait correlations can become maladaptive following r…
Ecological conditions such as nutrition can change genetic covariances between traits and accelerate or slow down trait evolution. Since adaptive trait correlations can become maladaptive following rapid environmental change, poor or stressful environments are expected to weaken genetic covariances, thereby increasing the opportunity for independent evolution of traits. Here, we demonstrate the differences in genetic covariance among multiple behavioral and morphological traits (exploration, aggression and body weight) between southern field crickets (Gryllus bimaculatus) raised in favorable (free-choice) versus stressful (protein-deprived) nutritional environments. We also quantify the extent to which differences in genetic covariance structures contribute to the potential for the independent evolution of these traits. We demonstrate that protein-deprived environments tend to increase the potential for traits to evolve independently, which is caused by genetic covariances that are significantly weaker for crickets raised on protein-deprived versus free-choice diets. The weakening effects of stressful environments on genetic covariances tended to be stronger in males than in females. The weakening of the genetic covariance between traits under stressful nutritional environments was expected to facilitate the opportunity for adaptive evolution across generations. Therefore, the multivariate gene-by-environment interactions revealed here may facilitate behavioral and morphological adaptations to rapid environmental change. This article is protected by copyright. All rights reserved.