Vitellogenin synthesis in primary cultures of fish liver cells as endpoint for in vitro screening of the (anti)estrogenic activity of chemical substances

Concern over possible adverse effects of endocrine-disrupting compounds on fish has caused the development of appropriate testing methods. In vitro screening assays may provide initial information on endocrine activities of a test compound and thereby may direct and optimize subsequent testing. Induction of vitellogenin (VTG) is used as a biomarker of exposure of fish to estrogen-active substances. Since VTG induction can be measured not only in vivo but also in fish hepatocytes in vitro, the use of VTG induction response in isolated fish liver cells has been suggested as in vitro screen for identifying estrogenic-active substances. The main advantages of the hepatocyte VTG assay are considered its ability to detect effects of estrogenic metabolites, since hepatocytes in vitro remain metabolically competent, and its ability to detect both estrogenic and anti-estrogenic effects. In this article, we critically review the current knowledge on the VTG response of cultured fish hepatocytes to (anti)estrogenic substances. In particular, we discuss the sensitivity, specificity, and variability of the VTG hepatocyte assay. In addition, we review the available data on culture factors influencing basal and induced VTG production, the response to natural and synthetic estrogens as well as to xenoestrogens, the detection of indirect estrogens, and the sources of assay variability. The VTG induction in cultured fish hepatocytes is clearly influenced by culture conditions (medium composition, temperature, etc.) and culture system (hepatocyte monolayers, aggregates, liver slices, etc.). The currently available database on estrogen-mediated VTG induction in cultured teleost hepatocytes is too small to support conclusive statements on whether there exist systematic differences of the VTG response between in vitro culture systems, VTG analytical methods or fish species. The VTG hepatocyte assay detects sensitively natural and synthetic estrogens, whereas the response to xenoestrogens appears to be more variable. The detection of weak estrogens can be critical due to the overshadow with cytotoxic concentrations. Moreover, the VTG hepatocyte assay is able to detect antiestrogens as well as indirect estrogens, i.e substances which require metabolic activation to induce an estrogenic response. Nevertheless, more chemicals need to be analysed to corroborate this statement. It will be necessary to establish standardized protocols to minimize assay variability, and to develop a set of pass-fail criteria as well as cut-offs for designating positive and negative responses.

The effects of omega -3 fatty acid -enriched fish on C -reactive protein levels in postmenopausal women

Coronary heart disease (CHD) is the leading cause of death in women and rates markedly increase among women after 65 years of age. C-reactive protein (CRP) is a new clinical indicator of atherosclerotic-related inflammation with a direct pathogenic role. Studies show lifestyle factors can modulate CRP. Omega-3 fatty acids have anti-inflammatory properties and studies suggest that eating fish high in omega-3 fatty acids may lower CHD risk in women. This study sought to assess the possible role of omega-3 fatty acids in the reduction of CHD-related inflammation by investigating the effect of fish consumption on CRP levels. Methods. Twenty-four healthy postmenopausal women were randomly assigned to a fish group (usual diet plus two servings per week of enriched fish) or control group (usual diet with no fatty fish) for eight weeks. Omega-3 fatty acid-enriched fish developed by the West Virginia University Aquaculture Division was used. Serum CRP, serum interleukin-6 (IL-6), and the fatty acid content of red blood cells (RBC) were measured before and after the study. Women also completed food records. RESULTS: Baseline levels of CRP were low (85% of the fish group had normal levels) and few changes in CRP risk category were observed. Mean IL-6 levels were reduced by 27% and 35% in the fish and control groups, respectively (p for between-group difference = 0.60). Changes in RBC fatty acid composition were not statistically significant. Compared to control women, women in the fish group had greater reductions in mean triglycerides (p = 0.08), total cholesterol (P = 0.04), and LDL cholesterol levels (p = 0.06). Baseline dietary intake of total and monounsaturated fatty acids tended to be positively associated with baseline CRP, while vitamin E intake was inversely related. Saturated fat intake tended to have a positive association with IL-6. Conclusions. Findings regarding the effect of two servings of fish on CRP and IL-6 levels are inconclusive due to low baseline levels of CRP and IL-6. However, results indicate two servings of fatty fish have favorable effects on blood lipids. The relationship of dietary components with CRP and IL-6 is complex and further research is needed to determine the varying roles of diet on the inflammatory process. ^

Strontium isotope ratios of fish teeth from ODP sites in the central North Pacific

Strontium isotopic compositions of ichthyoliths (microscopic fish remains) in deep-sea clays recovered from the North Pacific Ocean (ODP holes 885A, 886B, and 886C) are used to provide stratigraphic age control within these otherwise undatable sediments. Age control within the deep-sea clays is crucial for determining changes in sedimentation rates, and for calculating fluxes of chemical and mineral components to the sediments. The Sr isotopic ages are in excellent agreement with independent age datums from above (diatom ooze), below (basalt basement) and within (Cretaceous-Tertiary boundary) the clay deposit. The 87Sr/86Sr ratios of fish teeth from the top of the pelagic clay unit (0.7089891), indicate an Late Miocene age (5.8 Ma), as do radiolarian and diatom biostratigraphic ages in the overlying diatom ooze. The 87Sr/86Sr ratio (0.707887) is consistent with a Cretaceous-Tertiary boundary age, as identified by anomalously high iridium, shocked quartz, and sperules in Hole 886C. The 87Sr/86Sr ratios of pretreated fish teeth from the base of the clay unit are similar to Late Cretaceous seawater (0.707779-0.7075191), consistent with radiometric ages from the underlying basalt of 81 Ma. Calculation of sedimentation rates based on Sr isotopic ages from Hole 886C indicate an average sedimentation rate of 17.7 m/Myr in Unit II (diatom ooze), 0.55 m/Myr in Unit IIIa (pelagic clay), and 0.68 m/Myr in Unit IIIb (distal hydrothermal precipitates). The Sr isotopic ages indicate a period of greatly reduced sedimentation (or possible hiatus) between about 35 and 65 Ma (Eocene-Paleocene), with a linear sedimentation rate of only 0.04 m/Myr The calculated sedimentation rates are generally inversely proportional to cobalt accumulation rates and ichthyolith abundances. However, discrepancies between Sr isotope ages and cobalt accumulation ages of l0-15 Myr are evident, particularly in the middle of the clay unit IIIa (Oligocene-Paleocene).

Strontium isotope ratios and concentrations in fossil fish teeth

We analyzed 87Sr/86Sr ratios in foraminifera, pore fluids, and fish teeth for samples ranging in age from Eocene to Pleistocene from four Ocean Drilling Program sites distributed around the globe: Site 1090 in the Cape Basin of the Southern Ocean, Site 757 on the Ninetyeast Ridge in the Indian Ocean, Site 807 on the Ontong-Java Plateau in the western equatorial Pacific, and Site 689 on the Maud Rise in the Southern Ocean. Sr isotopic ratios for dated foraminifera consistently plot on the global seawater Sr isotope curve. For Sites 1090, 757, and 807 Sr isotopic values of the pore fluids are generally less radiogenic than contemporaneous seawater values, as are values for fossil fish teeth. In contrast, pore fluid 87Sr/86Sr values at Site 689 are more radiogenic than contemporaneous seawater, and the corresponding fish teeth also record more radiogenic values. Thus, Sr isotopic values preserved in fossil fish teeth are consistently altered in the direction of the pore fluid values; furthermore, there is a correlation between the magnitude of the offset between the pore fluids and the seawater curve, and the associated offset between the fish teeth and the seawater curve. These data suggest that the hydroxyfluorapatite of the fossil fish teeth continues to recrystallize and exchange Sr with its surroundings during burial and diagenesis. Therefore, Sr chemostratigraphy can be used to determine rough ages for fossil fish teeth in these cores, but cannot be used to fine-tune age models. In contrast to the Sr isotopic system, our Nd concentration data, combined with published isotopic and rare earth element data, suggest that fish teeth acquire Nd during early diagenesis while they are still in direct contact with seawater. The concentrations of Nd acquired at this stage are extremely high relative to the concentrations in surrounding pore fluids. As a result, Nd isotopes are not altered during burial and later diagenesis. Therefore, fossil fish teeth from a variety of marine environments preserve a reliable and robust record of deep seawater Nd isotopic compositions from the time of deposition.

Crustaceans and fish abundances and species at and around artificially introduced tetrapod fields in the southern North Sea, 2010-2011

In the coming decades, artificial defence structures will increase in importance worldwide for the protection of coasts against the impacts of global warming. However, the ecological effects of such structures on the natural surroundings remain unclear. We investigated the impact of experimentally introduced tetrapod fields on the demersal fish community in a hard-bottom area in the southern North Sea. The results indicated a significant decrease in fish abundance in the surrounding area caused by migration effects towards the artificial structures. Diversity (HB) and evenness (E) values exhibited greater variation after the introduction of the tetrapods. Additionally, a distinct increase in young-of-the-year (YOY) fish was observed near the structures within the second year after introduction. We suggest that the availability of adequate refuges in combination with additional food resources provided by the artificial structures has a highly species-specific attraction effect. However, these findings also demonstrate that our knowledge regarding the impact of artificial structures on temperate fish communities is still too limited to truly understand the ecological processes that are initiated by the introduction of artificial structures. Long-term investigations and additional experimental in situ work worldwide will be indispensable for a full understanding of the mechanisms by which coastal defence structures interact with the coastal environment.

Fish diversity and traditional fishing methods in semiarid irrigated system in the Bajo Vinalopó region, Southeastern Spain

The aim of this paper is to obtain a comprehensive picture of the importance of the fish fauna in the wetlands and coastal lagoons of the Bajo Vinalopó region (Alicante, South eastern Spain) and the ecological, historical and cultural value of the traditional knowledge on fishing maintained by local people. We have compiled data from different information sources: (1) the revision of historical archives, (2) personal interviews and collaborative research, and (3) ecological and water quality data. The results show that the area sustains important fish fauna diversity (17 species) and that local people have inherited a considerable traditional knowledge on fishing methods (11 modalities), on the maintenance and sound management of the water system and on the ecology and behaviour of fish. We conclude that a comprehensive consideration of all these ecological, historical and socio-cultural aspects related to fish and fishing shows clearly the value of this ecological and cultural heritage and provides a necessary base for a sustainable management of the area.

Variations in coastal fish species composition captured by traps in Romsdalsfjord, Western Norway

Fish traps are widely used in Norwegian fjords, especially those designed for monitoring salmonid populations in the marine environment, although many other marine fish species are also captured. The composition and spatio-temporal variations of fish species captured by fish traps were monitored in five different coastal locations throughout the Romsdalsfjord region, Western Norway, from May to August during the three consecutive years (2011–2013). Twenty-three fish species were captured by traps in coastal waters, both resident and migratory fishes. The most common fish and with greater catchability were saithe (Pollachis virens) and sea trout (Salmo trutta), followed by cod (Gadus morhua), pollack (P. pollachius), herring (Clupea harengus) and mackerels (Trachurus trachurus and Scomber scombrus). However, the captured assemblage presented great spatial and seasonal variations, in terms of mean daily catch, probably associated with hydrographical conditions and migrational patterns. Information obtained in this study will help us to better understand the compositions and dynamic of coastal fish populations inhabiting Norwegian coastal waters. In addition, traps are highly recommended as a management tool for fish research (e.g. fish-tagging experiments, mark and recapture) and conservation purposes (coastal use and fisheries studies).

Ability of some plant extracts, traditionally used to treat ciguatera fish poisoning, to prevent the in vitro neurotoxicity produced by sodium channel activators

The effects of 31 plant extracts, which most are traditionally used to treat ciguatera fish poisoning in the Pacific area, were Studied on the cytotoxicity of mouse neuroblastoma cells produced by ouabain, veratridine and/or brevetoxin-3 or Pacific ciguatoxin-1. The cell viability was determined using a quantitative colorimetric method. A marked cytotoxicity of seven of the 31 plant extracts studied, was observed. Despite this, these plant extracts were suspected to contain active compound(s) against the cytotoxicity produced by brevetoxin (2 extracts), brevetoxin, ouabain and/or veratridine (3 extracts), or only against that of ouabain and/or veratridine (2 extracts). Among the 24 plant extracts that exhibited by themselves no cytotoxicity, 22 were active against the effect of brevetoxin or against that of both veratridine and brevetoxin. similar results were obtained when the seven most active plant extracts were reassayed using ciguatoxin instead of brevetoxin. In conclusion, the present work reports the first activity assessment of some plant extracts, achieved in vitro on a quite large scale. The fact that 27 plant extracts were found to exert, in vitro, a protective effect against the action of ciguatoxin and/or brevetoxin, paves the way for finding new active compounds to treat ciguatera fish poisoning, provided these compounds also reverse the effects of sodium channel activators. (c) 2005 Elsevier Ltd. All rights reserved.

An incentivized auction based group-selling approach for demand response management in V2G systems

Vehicle-to-Grid (V2G) system with efficient Demand Response Management (DRM) is critical to solve the problem of supplying electricity by utilizing surplus electricity available at EVs. An incentivilized DRM approach is studied to reduce the system cost and maintain the system stability. EVs are motivated with dynamic pricing determined by the group-selling based auction. In the proposed approach, a number of aggregators sit on the first level auction responsible to communicate with a group of EVs. EVs as bidders consider Quality of Energy (QoE) requirements and report interests and decisions on the bidding process coordinated by the associated aggregator. Auction winners are determined based on the bidding prices and the amount of electricity sold by the EV bidders. We investigate the impact of the proposed mechanism on the system performance with maximum feedback power constraints of aggregators. The designed mechanism is proven to have essential economic properties. Simulation results indicate the proposed mechanism can reduce the system cost and offer EVs significant incentives to participate in the V2G DRM operation.