Increasing abundance of microplastics (MP) in marine and freshwaters is currently one of the greatest environmental concerns. Since plastics are fairly resistant to chemical decomposition, breakdown ...and reutilization of MP carbon complexes requires microbial activity. Currently, only a few microbial isolates have been shown to degrade MPs, and direct measurements of the fate of the MP carbon are still lacking. We used compound-specific isotope analysis to track the fate of fully labelled
C-polyethylene (PE) MP carbon across the aquatic microbial-animal interface. Isotopic values of respired CO
and membrane lipids showed that MP carbon was partly mineralized and partly used for cell growth. Microbial mineralization and assimilation of PE-MP carbon was most active when inoculated microbes were obtained from highly humic waters, which contain recalcitrant substrate sources. Mixotrophic algae (Cryptomonas sp.) and herbivorous zooplankton (Daphnia magna) used microbial mediated PE-MP carbon in their cell membrane fatty acids. Moreover, heteronanoflagellates and mixotrophic algae sequestered MP carbon for synthesizing essential ω-6 and ω-3 polyunsaturated fatty acids. Thus, this study demonstrates that aquatic micro-organisms can produce, biochemically upgrade, and trophically transfer nutritionally important biomolecules from PE-MP.
Orexin (hypocretin) peptides and their two known G‐protein‐coupled receptors play essential roles in sleep–wake control and powerfully influence other systems regulating appetite/metabolism, stress ...and reward. Consequently, drugs that influence signalling by these receptors may provide novel therapeutic opportunities for treating sleep disorders, obesity and addiction. It is therefore critical to understand how these receptors operate, the nature of the signalling cascades they engage and their physiological targets. In this review, we evaluate what is currently known about orexin receptor signalling cascades, while a sister review (Leonard & Kukkonen, this issue) focuses on tissue‐specific responses. The evidence suggests that orexin receptor signalling is multifaceted and is substantially more diverse than originally thought. Indeed, orexin receptors are able to couple to members of at least three G‐protein families and possibly other proteins, through which they regulate non‐selective cation channels, phospholipases, adenylyl cyclase, and protein and lipid kinases. In the central nervous system, orexin receptors produce neuroexcitation by postsynaptic depolarization via activation of non‐selective cation channels, inhibition of K+ channels and activation of Na+/Ca2+ exchange, but they also can stimulate the release of neurotransmitters by presynaptic actions and modulate synaptic plasticity. Ca2+ signalling is also prominently influenced by these receptors, both via the classical phospholipase C−Ca2+ release pathway and via Ca2+ influx, mediated by several pathways. Upon longer‐lasting stimulation, plastic effects are observed in some cell types, while others, especially cancer cells, are stimulated to die. Thus, orexin receptor signals appear highly tunable, depending on the milieu in which they are operating.
Linked Articles
This article is part of a themed section on Orexin Receptors. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2014.171.issue‐2
Emissions originating from ship traffic in European sea areas were modelled using the Ship Traffic Emission Assessment Model (STEAM), which uses Automatic Identification System data to describe ship ...traffic activity. We have estimated the emissions from ship traffic in the whole of Europe in 2011. We report the emission totals, the seasonal variation, the geographical distribution of emissions, and their disaggregation between various ship types and flag states. The total ship emissions of CO2, NOx, SOx, CO, and PM2.5 in Europe for year 2011 were estimated to be 121, 3.0, 1.2, 0.2, and 0.2 million tons, respectively. The emissions of CO2 from the Baltic Sea were evaluated to be more than a half (55 %) of the emissions of the North Sea shipping; the combined contribution of these two sea regions was almost as high (88 %) as the total emissions from ships in the Mediterranean. As expected, the shipping emissions of SOx were significantly lower in the SOx Emission Control Areas, compared with the corresponding values in the Mediterranean. Shipping in the Mediterranean Sea is responsible for 40 and 49 % of the European ship emitted CO2 and SOx emissions, respectively. In particular, this study reported significantly smaller emissions of NOx, SOx, and CO for shipping in the Mediterranean than the EMEP inventory; however, the reported PM2.5 emissions were in a fairly good agreement with the corresponding values reported by EMEP. The vessels registered to all EU member states are responsible for 55 % of the total CO2 emitted by ships in the study area. The vessels under the flags of convenience were responsible for 25 % of the total CO2 emissions.
Tire rubber microparticles (TRPs) entering aquatic ecosystems through stormwater runoffs is a significant challenge. TRPs are formed by the abrasion of tires with the road surface and include ...chemical additives that are an additional cause for concern. Currently, information on the molecular effects of TRPs, or especially its additives, in freshwater organisms is scarce. To address this problem, an array covering different cellular processes has been designed for the freshwater midge Chironomus riparius. Fourth-instar larvae were exposed to two concentrations of TRPs (1 mg L−1, 10 mg L−1) and tire rubber leachates (TRLs) (0,0125 %, 5 %) to evaluate the transcriptional activity by Real-Time PCR. To assess acute toxicity, larvae were exposed for 24 h and genes related to the endocrine system, stress response, DNA repair mechanisms, immune system, oxidative stress, and detoxification mechanisms were evaluated. The activity of the enzymes: glutathione S-transferase (GST) and catalase was also examined. The main pathway affected was the stress response showing overexpression of HSPs (HSC70.3, HSC70.4, HSC70.5, HSP60). Moreover, there was a reduction of the GSTd3 and catalase disrupting the antioxidant system. The upregulation of InR indicates a potential disturbance in the insulin pathway and ABCB6 activation only in TRPs exposure suggests its potential implication in their transport. However, most of these alterations are caused by TRLs, showing higher toxicity than TRPs. The results obtained in this work provide the first approach at the molecular and cellular levels to elucidate the impact of TRLs in freshwater organisms. To perform a realistic evaluation of the TR effects, additional research is required to assess the TR's long-term effects at the molecular level.
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•TR disrupts detoxification and stress system in C. riparius after 24 h exposure.•TRLs have shown higher toxicity to C. riparius than TRPs.•Zinc is the main metal present in TRLs producing toxicity.•Analyzing effects at transcriptional level enables assessing real scenarios.
A method is presented for the evaluation of the exhaust emissions of marine traffic, based on the messages provided by the Automatic Identification System (AIS), which enable the positioning of ship ...emissions with a high spatial resolution (typically a few tens of metres). The model also takes into account the detailed technical data of each individual vessel. The previously developed model was applicable for evaluating the emissions of NOx, SOx and CO2. This paper addresses a substantial extension of the modelling system, to allow also for the mass-based emissions of particulate matter (PM) and carbon monoxide (CO). The presented Ship Traffic Emissions Assessment Model (STEAM2) allows for the influences of accurate travel routes and ship speed, engine load, fuel sulphur content, multiengine setups, abatement methods and waves. We address in particular the modeling of the influence on the emissions of both engine load and the sulphur content of the fuel. The presented methodology can be used to evaluate the total PM emissions, and those of organic carbon, elemental carbon, ash and hydrated sulphate. We have evaluated the performance of the extended model against available experimental data on engine power, fuel consumption and the composition-resolved emissions of PM. We have also compared the annually averaged emission values with those of the corresponding EMEP inventory, As example results, the geographical distributions of the emissions of PM and CO are presented for the marine regions of the Baltic Sea surrounding the Danish Straits.
An extensive inventory of marine exhaust emissions is presented in the northern European emission control area (ECA) in 2009 and 2011. The emissions of SOx, NOx, CO2, CO and PM2.5 were evaluated ...using the Ship Traffic Emission Assessment Model (STEAM). We have combined the information on individual vessel characteristics and position reports generated by the automatic identification system (AIS). The emission limitations from 2009 to 2011 have had a significant impact on reducing the emissions of both SOx and PM2.5. The predicted emissions of SOx originated from IMO (International Maritime Organization)-registered marine traffic have been reduced by 29%, from 320 kt to 231 kt, in the ECA from 2009 to 2011. The corresponding predicted reduction of PM2.5 emissions was 17%, from 72 kt to 61 kt. The highest CO2 and PM2.5 emissions in 2011 were located in the vicinity of the coast of the Netherlands, in the English Channel, near the south-eastern UK and along the busiest shipping lines in the Danish Straits and the Baltic Sea. The changes of emissions and the financial costs caused by various regulative actions since 2005 were also evaluated, based on the increased direct fuel costs. We also simulated the effects and direct costs associated with the forthcoming switch to low-sulfur distillate fuels in 2015. According to the projections for the future, there will be a reduction of 87% in SOx emissions and a reduction of 48% in PM2.5 emissions in 2015, compared with the corresponding shipping emissions in 2011 in the ECA. The corresponding relative increase in fuel costs for all IMO-registered shipping varied between 13% and 69%, depending on the development of the prices of fuels and the use of the sulfur scrubber equipment.
Multiple homeostatic systems are regulated by orexin (hypocretin) peptides and their two known GPCRs. Activation of orexin receptors promotes waking and is essential for expression of normal sleep ...and waking behaviour, with the sleep disorder narcolepsy resulting from the absence of orexin signalling. Orexin receptors also influence systems regulating appetite/metabolism, stress and reward, and are found in several peripheral tissues. Nevertheless, much remains unknown about the signalling pathways and targets engaged by native receptors. In this review, we integrate knowledge about the orexin receptor signalling capabilities obtained from studies in expression systems and various native cell types (as presented in Kukkonen and Leonard, this issue of British Journal of Pharmacology) with knowledge of orexin signalling in different tissues. The tissues reviewed include the CNS, the gastrointestinal tract, the pituitary gland, pancreas, adrenal gland, adipose tissue and the male reproductive system. We also summarize the findings in different native and recombinant cell lines, especially focusing on the different cascades in CHO cells, which is the most investigated cell line. This reveals that while a substantial gap exists between what is known about orexin receptor signalling and effectors in recombinant systems and native systems, mounting evidence suggests that orexin receptor signalling is more diverse than originally thought. Moreover, rather than being restricted to orexin receptor ‘overexpressing’ cells, this signalling diversity may be utilized by native receptors in a site‐specific manner.
Linked Articles
This article is part of a themed section on Orexin Receptors. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2014.171.issue‐2
Effects of fullerene-spiked sediment on a benthic organism,
Lumbriculus variegatus (Oligochaeta), were investigated. Survival, growth, reproduction, and feeding rates were measured to assess possible ...adverse effects of fullerene agglomerates produced by water stirring and then spiked to a natural sediment.
L. variegatus were exposed to 10 and 50 mg fullerenes/kg sediment dry mass for 28 d. These concentrations did not impact worm survival or reproduction compared to the control. Feeding activities were slightly decreased for both concentrations indicating fullerenes’ disruptive effect on feeding. Depuration efficiency decreased in the high concentration only. Electron and light microscopy and extraction of the worm fecal pellets revealed fullerene agglomerates in the gut tract but not absorption into gut epithelial cells. Micrographs also indicated that 16% of the epidermal cuticle fibers of the worms were not present in the 50 mg/kg exposures, which may make worms susceptible to other contaminants.
► Effects of fullerene-spiked sediment on black worms were investigated. ► Survival, growth, reproduction, and feeding rates were measured. ► Exposure did not impact worm survival or reproduction. ► Feeding rates and depuration efficiency were decreased. ► Worms transferred fullerenes from the sediment to the sediment surface.
Exposure to fullerene-spiked sediment decreased black worms’ feeding and depuration efficiency, but fullerenes did not appear to be absorbed into the microvilli.
Particulate matter (PM) air pollution is a human lung carcinogen; however, the components responsible have not been identified. We assessed the associations between PM components and lung cancer ...incidence.
We used data from 14 cohort studies in eight European countries. We geocoded baseline addresses and assessed air pollution with land-use regression models for eight elements (Cu, Fe, K, Ni, S, Si, V and Zn) in size fractions of PM2.5 and PM10. We used Cox regression models with adjustment for potential confounders for cohort-specific analyses and random effect models for meta-analysis.
The 245,782 cohort members contributed 3,229,220person–years at risk. During follow-up (mean, 13.1years), 1878 incident cases of lung cancer were diagnosed. In the meta-analyses, elevated hazard ratios (HRs) for lung cancer were associated with all elements except V; none was statistically significant. In analyses restricted to participants who did not change residence during follow-up, statistically significant associations were found for PM2.5 Cu (HR, 1.25; 95% CI, 1.01–1.53 per 5ng/m3), PM10 Zn (1.28; 1.02–1.59 per 20ng/m3), PM10 S (1.58; 1.03–2.44 per 200ng/m3), PM10 Ni (1.59; 1.12–2.26 per 2ng/m3) and PM10 K (1.17; 1.02–1.33 per 100ng/m3). In two-pollutant models, associations between PM10 and PM2.5 and lung cancer were largely explained by PM2.5 S.
This study indicates that the association between PM in air pollution and lung cancer can be attributed to various PM components and sources. PM containing S and Ni might be particularly important.
•Particulate matter air pollution is a human lung carcinogen.•The particulate matter components being responsible have not been identified.•This study indicates that various components are responsible.•The sulfur and nickel containing particles might be particularly important.
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