Anchoring novel molecular biomarker responses to traditional responses in fish exposed to environmental contamination

The responses of Dicentrarchus labrax and Liza aurata to aquatic pollution were assessed in a contaminated coastal lagoon, using both traditional and novel biomarkers combined. DNA damage, assessed by comet assay, was higher in both fish species from the contaminated sites, whereas levels of cytochrome P450 1A1 gene expression were not significantly altered. The liver histopathological analysis also revealed significant lesions in fish from contaminated sites. Alterations in ras and xpf genes were analysed and additional pollutant-responsive genes were identified. While no alterations were found in ras gene, a downregulation of xpf gene was observed in D. labrax from a contaminated site. Suppression subtractive hybridization applied to D. labrax collected at a contaminated site, revealed altered expression in genes involved in energy metabolism, immune system activity and antioxidant response. The approach and results reported herein demonstrate the utility of anchoring traditional biomarker responses alongside novel biomarker responses.     

Integrating archaeology and ancient DNA analysis to address invasive species colonization in the Gulf of Alaska

The intentional and unintentional movement of plants and animals by humans has transformed ecosystems and landscapes globally. Assessing when and how a species was introduced are central to managing these transformed landscapes, particularly in island environments. In the Gulf of Alaska, there is considerable interest in the history of mammal introductions and rehabilitating Gulf of Alaska island environments by eradicating mammals classified as invasive species. The Arctic ground squirrel (Urocitellus parryii) is of concern because it affects vegetation and seabirds on Gulf of Alaska islands. This animal is assumed to have been introduced by historic settlers; however, ground squirrel remains in the prehistoric archaeological record of Chirikof Island, Alaska, challenge this timeline and suggest they colonized the islands long ago. We used 3 lines of evidence to address this problem: direct radiocarbon dating of archaeological squirrel remains; evidence of prehistoric human use of squirrels; and ancient DNA analysis of dated squirrel remains. Chirikof squirrels dated to at least 2000 years ago, and cut marks on squirrel bones suggested prehistoric use by people. Ancient squirrels also shared a mitochondrial haplotype with modern Chirikof squirrels. These results suggest that squirrels have been on Chirikof longer than previously assumed and that the current population of squirrels is closely related to the ancient population. Thus, it appears ground squirrels are not a recent, human‐mediated introduction and may have colonized the island via a natural dispersal event or an ancient human translocation.     

Comparative study of polyhydroxyalkanoates production from acidified and anaerobically treated brewery wastewater using enriched mixed microbial culture

The production of polyhydroxyalkanoates(PHA) from wastewaters using microbial mixed cultures(MMC) has been attracting increased interest because of PHA's biodegradability characteristics. Production of PHA by an MMC enriched with PHA-accumulating bacteria was compared using anaerobically treated and acidified brewery wastewaters under various feeding strategies, namely pulse and batch feed addition. To obtain an enriched MMC, a sequencing batch reactor was inoculated with activated sludge fed with acetate and subjected to aerobic dynamic feeding. The enriched MMC was able to accumulate PHA up to 72.6% of cell dry weight(CDW) with pulse addition of acetate controlled by the dissolved oxygen(DO) concentration in the reactor. In a batch accumulation experiment with acetate,the PHA content achieved(28.5% CDW) was less than that of the pulse feeding strategy with the same amount of acetate(～2000 mg C/L). Using anaerobically treated and acidified brewery wastewater fed in pulses, the maximum PHA accumulated by the enriched MMC was similar for both wastewaters(45% CDW), in spite of the higher volatile fatty acid concentration in acidified brewery wastewater. The pulse feed addition controlled by the DO concentration was difficult to implement for wastewater as compared to acetate because the difference in DO concentration between substrate availability and depletion was low. For the batch addition of acidified wastewater, a slightly lower PHA content(39%CDW) was obtained. These results show that both brewery wastewaters can be utilized for PHA production with a similar maximum PHA storage capacity.     

Oxidative stress in Nile tilapia (Oreochromis niloticus) and armored catfish (Pterygoplichthys anisitsi) exposed to diesel oil

Considering that diesel oil is one of the most common aquatic contaminants, we compare the oxidative stress between two species of fish with different habitats (Pterygoplichthys anisitsi, benthic and Oreochromis niloticus, nektonic) exposed to diesel oil. Malondialdehyde concentrations (MDA) and the activities of ethoxyresorufin-O-deethylase (EROD), glutathione S-transferase (GST), catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase were all analyzed in the fishes' livers and gills after 2 and 7 days of exposure to different concentrations of diesel (0.1 and 0.5 mL/L). In the tilapia, MDA levels and the activities of EROD and GST activity in the liver, as well as MDA levels and the activities of GST and SOD in the gill had statistically significant differences between the treatments and between the times of exposure. For the catfish, the same occurred in the case of MDA, EROD, and SOD in the liver and in CAT and SOD in the gills. There were significant differences in the enzyme activity and lipid peroxidation between the species. Although the activity of most enzymes seemed to be more expressive and responsive to diesel in O. niloticus, diesel oil also caused significant effects on oxidative stress parameters in P. anisitsi, even though this species is benthic and thus has less access to insoluble fractions of diesel oil. Therefore, both species can be used as sentinel organisms in environmental biomonitoring of diesel contamination.     

Dye decomposition and air de-pollution performance of TiO2/SiO2 and N-TiO2/SiO2 photocatalysts coated on Portland cement mortar substates

Environmental Science and Pollution Research - In this study, the newly synthesized TiO2 and N doped TiO2 clusters were added to silica sol to synthesize N-TiO2/SiO2 composites via the...     

Dioxin alters inflammatory responses to lipopolysaccharide

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) has well characterized effects on specific immune responses, but the effects on the innate immune system are less understood. The effect of TCDD on inflammatory responses induced by lipopolysaccharide (LPS) was evaluated in C57BL/6J female mice. Mice were treated with 30?µg?kg^?1 TCDD or vehicle once, p.o., and 4 days later, animals received LPS (0.05?×?10⁷?EU?kg^?1, i.p.) or vehicle. Inflammatory mediators and the liver injury marker, alanine aminotransferase (ALT), were measured, and liver histology was evaluated. TCDD-treated animals had higher plasma ALT activity than vehicle-treated animals, but the effect was mild and time-dependent. Few changes in liver histopathology were observed, mainly represented in greater steatosis in TCDD/LPS-treated mice compared to mice treated with LPS or TCDD alone. LPS produced a time-dependent increase in the plasma concentrations of interleukins (IL)-6, -10, and -12 and interferon (IFN)-γ, tumor necrosis factor (TNF)-α, and monocyte chemoattractant protein (MCP)-1. With the exception of IL-12, concentrations of each of these mediators were higher in plasma of mice co-treated with TCDD and LPS compared to either agent alone. The dose–response curve for the concentration of IL-6 in plasma suggested that dioxin increased the potency of LPS to cause the release of this cytokine but not the maximal response. Co-treatment with TCDD and LPS also led to greater expression of mRNA for IL-10 and IFN-γ compared to either TCDD or LPS alone. These results suggest that TCDD changes the inflammatory cytokine profile induced by LPS and that LPS enhances the hepatic steatotic response to TCDD.     

Phosphorus removal by a fixed-bed hybrid polymer nanocomposite biofilm reactor

Eutrophication is one of the main challenges regarding the ecological quality of surface waters, phosphorus bioavailability being its main driver. In this context, a novel hybrid polymer nanocomposite (HPN-Pr) biofilm reactor aimed at integrated chemical phosphorus adsorption and biological removal was conceived. The assays pointed to removal of 1.2 mg P/g of reactive phosphorus and 1.01 mg P/g of total phosphorus under steady-state conditions. A mathematical adsorption–biological model was applied to predict reactor performance, which indicated that biological activity has a positive effect on reactor performance, increasing the amount of reactive phosphorus removed.     

A roadmap for the conservation of freshwater mussels in Europe

Europe has a long history of human pressure on freshwater ecosystems. As pressure continues to grow and new threats emerge, there is an urgent need for conservation of freshwater biodiversity and its ecosystem services. However, whilst some taxonomic groups, mainly vertebrates, have received a disproportionate amount of attention and funds, other groups remain largely off the public and scientific radar. Freshwater mussels (Bivalvia, Unionida) are an alarming example of this conservation bias and here we point out six conceptual areas that need immediate and long-term attention: knowledge, threats, socioeconomics, conservation, governance and education. The proposed roadmap aims to advance research, policy and education by identifying the most pressing priorities for the short- and long-term conservation of freshwater mussels across Europe.