WS22D nanosheets in 3D nanoflowers

In this work it has been established that 3D nanoflowers of WS2 synthesized by chemical vapour deposition are composed of few layer WS2 along the edges of the petals. An experimental study to understand the evolution of these nanostructures shows the nucleation and growth along with the compositional changes they undergo

Toxicity assessment of individual ingredients of synthetic-based drilling muds (SBMs)

Synthetic-based drilling muds (SBMs) offer excellent technical characteristics while providing improved environmental performance over other drilling muds. The low acute toxicity and high biodegradability of SBMs suggest their discharge at sea would cause minimal impacts on marine ecosystems, however, chronic toxicity testing has demonstrated adverse effects of SBMs on fish health. Sparse environmental monitoring data indicate effects of SBMs on bottom invertebrates. However, no environmental toxicity assessment has been performed on fish attracted to the cutting piles. SBM formulations are mostly composed of synthetic base oils, weighting agents, and drilling additives such as emulsifiers, fluid loss agents, wetting agents, and brine. The present study aimed to evaluate the impact of exposure to individual ingredients of SBMs on fish health. To do so, a suite of biomarkers [ethoxyresorufin-O-deethylase (EROD) activity, biliary metabolites, sorbitol dehydrogenase (SDH) activity, DNA damage, and heat shock protein] have been measured in pink snapper (Pagrus auratus) exposed for 21 days to individual ingredients of SBMs. The primary emulsifier (Emul S50) followed by the fluid loss agent (LSL 50) caused the strongest biochemical responses in fish. The synthetic base oil (Rheosyn) caused the least response in juvenile fish. The results suggest that the impact of Syndrill 80:20 on fish health might be reduced by replacement of the primary emulsifier Emul S50 with an alternative ingredient of less toxicity to aquatic biota. The research provides a basis for improving the environmental performance of SBMs by reducing the environmental risk of their discharge and providing environmental managers with information regarding the potential toxicity of individual ingredients. © 2011 Springer Science+Business Media B.V

Polymers of intrinsic microporosity as high temperature templates for the formation of nanofibrous oxides

The highly rigid molecular structure of Polymers of Intrinsic Microporosity (PIM) – associated with a high thermolysis threshold – combined with the possibility to fill intrinsic micropores allows the direct “one-step” templated conversion of metal nitrates into nano-structured metal oxides. This is demonstrated here with PIM-EA-TB and with PIM-1 for the conversion of Pr(NO3)3 to Pr6O1

Health Status of Sand Flathead (Platycephalus bassensis), Inhabiting an Industrialised and Urbanised Embayment, Port Phillip Bay, Victoria as Measured by Biomarkers of Exposure and Effects

Port Phillip Bay, Australia, is a large semi-closed bay with over four million people living in its catchment basin. The Bay receives waters from the Yarra River which drains the city of Melbourne, as well as receiving the discharges of sewage treatment plants and petrochemical and agricultural chemicals. A 1999 study demonstrated that fish inhabiting Port Phillip Bay showed signs of effects related to pollutant exposure despite pollution management practices having been implemented for over a decade. To assess the current health status of the fish inhabiting the Bay, a follow up survey was conducted in 2015. A suite of biomarkers of exposure and effects were measured to determine the health status of Port Phillip Bay sand flathead (Platycephalus bassensis), namely ethoxyresorufin-O-deethylase (EROD) activity, polycyclic aromatic hydrocarbons (PAH) biliary metabolites, carboxylesterase activity (CbE) and DNA damage (8-oxo-dG). The reduction in EROD activity in the present study suggests a decline in the presence of EROD activity-inducing chemicals within the Bay since the 1990s. Fish collected in the most industrialised/urbanised sites did not display higher PAH metabolite levels than those in less developed areas of the Bay. Ratios of PAH biliary metabolite types were used to indicate PAH contaminant origin. Ratios indicated fish collected at Corio Bay and Hobsons Bay were subjected to increased low molecular weight hydrocarbons of petrogenic origin, likely attributed to the close proximity of these sites to oil refineries, compared to PAH biliary metabolites in fish from Geelong Arm and Mordialloc.Quantification of DNA damage indicated a localised effect of exposure to pollutants, with a 10-fold higher DNA damage level in fish sampled from the industrial site of Corio Bay relative to the less developed site of Sorrento. Overall, integration of biomarkers by multivariate analysis indicated that the health of fish collected in industrialised areas was compromised, with biologically significant biomarkers of effects (LSI, CF and DNA damage) discriminating between individuals collected in industrialised areas from observations made in fish collected in less developed areas of the Bay

Hormonal signaling in cnidarians : do we understand the pathways well enough to know whether they are being disrupted?

Author Posting. © The Author, 2006. This is the author's version of the work. It is posted here by permission of Springer for personal use, not for redistribution. The definitive version was published in Ecotoxicology 16 (2007): 5-13, doi:10.1007/s10646-006-0121-1.Cnidarians occupy a key evolutionary position as basal metazoans and are ecologically important as predators, prey and structure-builders. Bioregulatory molecules (e.g., amines, peptides and steroids) have been identified in cnidarians, but cnidarian signaling pathways remain poorly characterized. Cnidarians, especially hydras, are regularly used in toxicity testing, but few studies have used cnidarians in explicit testing for signal disruption. Sublethal endpoints developed in cnidarians include budding, regeneration, gametogenesis, mucus production and larval metamorphosis. Cnidarian genomic databases, microarrays and other molecular tools are increasingly facilitating mechanistic investigation of signaling pathways and signal disruption. Elucidation of cnidarian signaling processes in a comparative context can provide insight into the evolution and diversification of metazoan bioregulation. Characterizing signaling and signal disruption in cnidarians may also provide unique opportunities for evaluating risk to valuable marine resources, such as coral reefs

Environmental sensing and response genes in cnidaria : the chemical defensome in the sea anemone Nematostella vectensis

Author Posting. © The Author(s), 2008. This is the author's version of the work. It is posted here by permission of Springer for personal use, not for redistribution. The definitive version was published in Cell Biology and Toxicology 24 (2008): 483-502, doi:10.1007/s10565-008-9107-5.The starlet sea anemone Nematostella vectensis has been recently established as a new model system for the study of the evolution of developmental processes, as cnidaria occupy a key evolutionary position at the base of the bilateria. Cnidaria play important roles in estuarine and reef communities, but are exposed to many environmental stressors. Here I describe the genetic components of a ‘chemical defensome’ in the genome of N. vectensis, and review cnidarian molecular toxicology. Gene families that defend against chemical stressors and the transcription factors that regulate these genes have been termed a ‘chemical defensome,’ and include the cytochromes P450 and other oxidases, various conjugating enyzymes, the ATP-dependent efflux transporters, oxidative detoxification proteins, as well as various transcription factors. These genes account for about 1% (266/27200) of the predicted genes in the sea anemone genome, similar to the proportion observed in tunicates and humans, but lower than that observed in sea urchins. While there are comparable numbers of stress-response genes, the stress sensor genes appear to be reduced in N. vectensis relative to many model protostomes and deuterostomes. Cnidarian toxicology is understudied, especially given the important ecological roles of many cnidarian species. New genomic resources should stimulate the study of chemical stress sensing and response mechanisms in cnidaria, and allow us to further illuminate the evolution of chemical defense gene networks.WHOI Ocean Life Institute and NIH R01-ES01591

MFO INDUCTION IN ATLANTIC SALMON (SALMO SALAR)DURING AND AFTER EXPOSURE TO BASS STRAIT CRUDE OIL

Biochemical markers of exposure (mixed function oxygenase: MFO as determined by ethoxyresorufin O-deethylase (EROD) activity) and of effect(sorbitol dehydrogenase:SDH) were investigated for use during and after exposure of Atlantic salmon (salmo salar) to low levels of Bass Strait crude oil water-accommodated fraction (WAF) and dispersed crude oil. EROD activity was significantly induced after only two days of exposure to dispersed oil,while four days of exposure were necessary to significantly induce EROD in the WAF-exposed salmon. Following the termination of exposure,EROD induction remained elevated for eight days in both the WAF-exposed and the dispersed oil-exposed fish. Dispersing the oil using Corexit 9527 produced similar EROD activity levels in salmon relative to WAF only. Serum SDH activity confirmed that no hepatocellular injury was caused by exposure of salmon to these levels of WAF or to dispersed Bass Strait crude oil. It is concluded that MFO induction,as measured by changes in EROD activity,can be used for confirmation of low-level exposure of commercial salmon stocks to petroleum contaminated waters for up to eight days after the event

Use of the Australian crimson-spotted rainbowfish (Melanotaenia fluviatilis) as a model test species for investigating the effects of endocrine disruptors

Few studies have investigated the potential reproductive effects of toxicants on Australian freshwater fish species. The present study uses the Australian rainbowfish (Melanotaenia fluviatilis) as a model for testing the potential effects of 17beta-estradiol. Groups of reproductively active rainbowfish were exposed to waterborne 17beta-estradiol (control, carrier control, and 30, 100, 300, and 1,000 ng/L) for 3- and 14-d periods. Biomarkers of both low ecological relevance (plasma estradiol and testosterone, phosphoprotein, gamma-glutamyltranspeptidase [GTP]) and high ecological relevance (egg counts, hatchability, larval lengths, histopathology) were measured and the relationships between these examined. Relative to the controls, exposed female rainbowfish had a decline in plasma estradiol. An increase in phosphoprotein (vitellogenin) also was observed after exposure to 1,000 ng/L after 3 d, and histological examination of the gonads showed an increase in oocyte atresia at 1,000 ng/L on days 3 and 14. Changes in egg production were observed at 300 and 1,000 ng/L. No changes were detected to egg hatchability and larval lengths of offspring. Although there were no changes in male rainbowfish plasma testosterone or the histological organization of testes, levels of phosphoprotein increased and GTP activities were increased after 3 d of exposure at all test concentrations, but these declined at day 14. The present study demonstrated that, though measurements at the biochemical level were responsive to 17beta-estradiol exposure, fewer changes were observed in markers of higher ecological relevance at the exposures concentrations and durations tested

Influence of the reproductive cycle on cytochrome P450 levels in the sea star Coscinasterias muricata

[article extract] Located in the mitochondria and endoplasmic reticulum, enzymes of the cytochrome P450 superfamily are involved in critical physiological processes including biosynthesis and metabolism of steroids, fatty acids and prostaglandins. In addition to metabolism of endogenous compounds, cytochrome P450 (P450) enzymes are involved in the biotransformation/detoxification of some organic xenobiotic compounds, including polyaromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs). P450 reactions often lead to more water-soluble and generally less toxic metabolites that are further metabolised by phase II reactions, for example glutathione S-transferases, to form more readily excretable products. However, some P450 reactions involving exogenous compounds result in products that are more toxic than their parent compound, a process known as bioactivation. Changes in levels or activities of detoxification enzymes, such as total P450 and its isoforms, in response to organic contaminant exposure have been previously used in sea stars as specific biomarkers of this contaminant class. Therefore, thorough examination of the natural fluctuations of these enzymes must be undertaken to allow comparison with exposed organisms. The response of total P450 has been shown to be influenced by factors including season, temperature, organism gender, nutritional status and size in both marine vertebrates and invertebrates