A multi-taxonomic framework for assessing relative petrochemical vulnerability of marine biodiversity in the Gulf of Mexico.

A fundamental understanding of the impact of petrochemicals and other stressors on marine biodiversity is critical for effective management, restoration, recovery, and mitigation initiatives. As species-specific information on levels of petrochemical exposure and toxicological response are lacking for the majority of marine species, a trait-based assessment to rank species vulnerabilities to petrochemical activities in the Gulf of Mexico can provide a more comprehensive and effective means to prioritize species, habitats, and ecosystems for improved management, restoration and recovery. To initiate and standardize this process, we developed a trait-based framework, applicable to a wide range of vertebrate and invertebrate species, that can be used to rank relative population vulnerabilities of species to petrochemical activities in the Gulf of Mexico.

20th Pollutant Responses in Marine Organisms (PRIMO 20): Global issues and fundamental mechanisms caused by pollutant stress in marine and freshwater organisms.

The 20th Pollutant Responses in Marine Organisms (PRIMO 20) conference provided a forum for scientists from around the world to communicate novel toxicological research findings specifically focused on aquatic organisms, by combining applied and basic research at the intersection of environmental and mechanistic toxicology. The work highlighted in this special issue of Aquatic Toxicology, a special issue of Marine Environmental Research, and presented through posters and presentations, encompass important and emerging topics in freshwater and marine toxicology. This includes multiple types of emerging contaminants including microplastics and UV filtering chemicals.

Bioreactivity and Sunlight Potentiation of Hybrid Polymer Nanoparticles in Oysters, .

Polymer dynamic organic theranostic spheres (PolyDOTS) are being studied as a photothermal ablation treatment of cancer and are activated by blue or near-infrared light. PolyDOTS or related hybrid polymeric nanoparticle products could be mass-produced, and it is expected that they, like any other engineered nanoparticle (ENP), could be found in aquatic environments. The purpose of this study was to investigate the potential toxicity of these types of hybrid nanoparticles on nontarget marine organisms.

Dietary Uptake of Cu Sorbed to Hydrous Iron Oxide is Linked to Cellular Toxicity and Feeding Inhibition in a Benthic Grazer.

Whereas feeding inhibition caused by exposure to contaminants has been extensively documented, the underlying mechanism(s) are less well understood. For this study, the behavior of several key feeding processes, including ingestion rate and assimilation efficiency, that affect the dietary uptake of Cu were evaluated in the benthic grazer Lymnaea stagnalis following 4-5 h exposures to Cu adsorbed to synthetic hydrous ferric oxide (Cu-HFO). The particles were mixed with a cultured alga to create algal mats with Cu exposures spanning nearly 3 orders of magnitude at variable or constant Fe concentrations, thereby allowing first order and interactive effects of Cu and Fe to be evaluated.

Cellular responses of eastern oysters, Crassostrea virginica, to titanium dioxide nanoparticles.

Because of the continued development and production of a variety of nanomaterials and nanoparticles, their uptake and effects on the biota of marine ecosystems must be investigated. Filter feeding bivalve molluscs are highly adapted for capturing particles from the external environment and readily internalize nano- and micro-sized particles through endocytosis, so they are commonly used as valuable indicator species for nanoparticle studies. In these studies, adult eastern oysters, Crassostrea virginica, were exposed to a range of titanium dioxide nanoparticle (TiO2-NP) concentrations (5, 50, 500, and 5000 μg/L) in conjunction with natural sunlight.

Resuspended contaminated sediments cause sublethal stress to oysters: A biomarker differentiates total suspended solids and contaminant effects.

Resuspended contaminated sediments represent an important route of contaminant exposure for aquatic organisms. During resuspension events, filter-feeding organisms are exposed to contaminants, in both the dissolved form (at the gills) and the particulate form (in the digestive system). In addition, these organisms must manage the physical stress associated with an increase in total suspended solids (TSS).

Short-term acute hypercapnia affects cellular responses to trace metals in the hard clams Mercenaria mercenaria.

Estuarine and coastal habitats experience large fluctuations of environmental factors such as temperature, salinity, partial pressure of CO2 ( [Formula: see text] ) and pH; they also serve as the natural sinks for trace metals. Benthic filter-feeding organisms such as bivalves are exposed to the elevated concentrations of metals in estuarine water and sediments that can strongly affect their physiology. The effects of metals on estuarine organisms may be exacerbated by other environmental factors.

Tissue specific responses of oysters, Crassostrea virginica, to silver nanoparticles.

Silver nanoparticle (AgNP) toxicity in eastern oysters, Crassostrea virginica, was investigated in both gill and hepatopancreas tissues, and compared to dissolved Ag exposures. Oysters were exposed to varying concentrations of AgNPs prepared with citrate coatings and dissolved Ag (AgNO₃) for 48 h and the effects on a suite of biomarkers of cellular stress were evaluated. Two biomarkers of cellular damage were evaluated-lysosomal destabilization rates of hepatopancreas cells as indicators of lysosomal damage, and lipid peroxidation as an indicator of oxidative damage.

Indicators of environmental stress: cellular biomarkers and reproductive responses in the Sydney rock oyster (Saccostrea glomerata).

We measured a suite of common biomarker responses for the first time in the Sydney rock oyster Saccostrea glomerata to evaluate their utility as biological effects measures for pollution monitoring. To examine the relationship between biomarker responses and population level effects, fertilisation and embryo development assays were also conducted. Adult oysters were deployed in two contaminated estuaries and a reference estuary in Sydney, Australia.

Uptake and depuration of the C- and E-genotypes of Vibrio vulnificus by the Eastern Oyster (Crassostrea virginica).

The human pathogen Vibrio vulnificus is a Gram-negative estuarine bacterium that infect via wounds and ingestion, and is the leading cause of seafood-borne death in the United States. Vibrio vulnificus is part of the naturally occurring flora of both estuaries and estuarine mollusks (especially oysters). Vibrio vulnificus is divided into two genotypes, including a clinically associated C-type, and an environmentally associated E-type that is more rarely involved in septicemia.

The effects of silver nanoparticles on oyster embryos.

Nanoparticles may be introduced into aquatic environments during production processes and also as a result of release following their use in various commercial formulations and biologic applications. Filter-feeding bivalve mollusks such as oysters are valuable model species for characterizing nanoparticle bioavailability and interactions with basic cellular processes. The adults release their gametes into the environment, so their embryos and larvae are also likely targets of nanoparticles.

Fullerene exposures with oysters: embryonic, adult, and cellular responses.

Oysters are an ecologically important group of filter-feeders, and a valuable toxicology model for characterizing the potential impacts of nanoparticles to marine organisms. Fullerene (C60) exposure studies with oysters, Crassostrea virginica, were conducted with a variety of biological levels, e.g.

Comparison of methods for evaluating acute and chronic toxicity in marine sediments.

Sublethal test methods are being used with increasing frequency to measure sediment toxicity, but little is known about the relative sensitivity of these tests compared to the more commonly used acute tests. The present study was conducted to compare the sensitivity of several acute and sublethal methods and to investigate their correlations with sediment chemistry and benthic community condition. Six sublethal methods (amphipod: Leptocheirus plumulosus survival, growth, and reproduction; polychaete: Neanthes arenaceodentata survival and growth; benthic copepod: Amphiascus tenuiremis life cycle; seed clam: Mercenaria mercenaria growth; oyster: Crassostrea virginica lysosome destabilization; and sediment-water interface testing with mussel embryos, Mytilus galloprovincialis) and two acute methods (amphipod survival with Eohaustorius estuarius and L.

Combined effects of temperature acclimation and cadmium exposure on mitochondrial function in eastern oysters Crassostrea virginica gmelin (Bivalvia: Ostreidae).

Cadmium and temperature have strong impacts on the metabolic physiology of aquatic organisms. To analyze the combined impact of these two stressors on aerobic capacity, effects of Cd exposure (50 microg/L) on mitochondrial function were studied in oysters (Crassostrea virginica) acclimated to 12 and 20 degrees C in winter and to 20 and 28 degrees C in fall. Cadmium exposure had different effects on mitochondrial bioenergetics of oysters depending on the acclimation temperature.

Regulation of metallothionein genes in the American oyster (Crassostrea virginica): ontogeny and differential expression in response to different stressors.

Metallothioneins (MTs) are typically low molecular weight (6-7 kDa), metal-binding proteins with characteristic repeating cysteine motifs (Cys-X-Cys or Cys-Xn-Cys) and a prolate ellipsoid shape containing single alpha- and beta-domains. While functionally diverse, they play important roles in metals homeostasis, detoxification and the stress response. The present study, combined with previous observations (e.

Effects of acclimation temperature and cadmium exposure on cellular energy budgets in the marine mollusk Crassostrea virginica: linking cellular and mitochondrial responses.

In order to understand the role of metabolic regulation in environmental stress tolerance, a comprehensive analysis of demand-side effects (i.e. changes in energy demands for basal maintenance) and supply-side effects (i.

Tissue-specific accumulation of cadmium in subcellular compartments of eastern oysters Crassostrea virginica Gmelin (Bivalvia: Ostreidae).

Cadmium distribution was studied in different subcellular fractions of gill and hepatopancreas tissues of eastern oysters Crassostrea virginica. Oysters were exposed for up to 21 days to low sublethal Cd concentrations (25 microg L(-1)). Gill and hepatopancreas tissues were sampled and divided into organelle fractions and cytosol by differential centrifugation.

Linkages between cellular biomarker responses and reproductive success in oysters--Crassostrea virginica.

The purpose of these studies was to evaluate if there were relationships between lysosomal destabilization or glutathione concentrations and gamete viability of oysters, Crassostrea virginica. Oysters were collected from field sites during the peak spawning period (May-June) during 2001 and 2002. Lysosomal destabilization rates and glutathione concentrations of hepatopancreas tissues (e.

Diversity of metallothioneins in the American oyster, Crassostrea virginica, revealed by transcriptomic and proteomic approaches.

Metallothioneins are typically low relative molecular mass (6000-7000), sulfhydryl-rich metal-binding proteins with characteristic repeating cysteine motifs (Cys-X-Cys or Cys-X(n)-Cys) and a prolate ellipsoid shape containing single alpha- and beta-domains. While functionally diverse, they play important roles in the homeostasis, detoxification and stress response of metals. The originally reported metallothionein of the American oyster, Crassostrea virginica showed the canonical molluscan alphabeta-domain structure.

Potential indicators of stress response identified by expressed sequence tag analysis of hemocytes and embryos from the American oyster, Crassostrea virginica.

A pilot program was initiated to identify genes from the American oyster, Crassostrea virginica, that are potentially involved in the stress response for use as bioindicators of exposure to environmental pollutants and to toxic and infectious agents. A PCR-based method was used to construct cDNA libraries from pooled embryos and the hemocytes of a single individual. A total of 998 randomly selected clones (expressed sequence tags, ESTs) were sequenced.

Detection of oxidative DNA damage in isolated marine bivalve hemocytes using the comet assay and formamidopyrimidine glycosylase (Fpg).

Organisms in polluted areas can be exposed to complex mixtures of chemicals; however, exposure to genotoxic contaminants can be particularly devastating. DNA damage can lead to necrosis, apoptosis, or heritable mutations, and therefore has the potential to impact populations as well as individuals. Single cell gel electrophoresis (the comet assay) is a simple and sensitive technique used to examine DNA damage in single cells.

Differential accumulation of heavy metals in the sea anemone Anthopleura elegantissima as a function of symbiotic state.

The accumulation of metals by the North American Pacific Coast temperate sea anemone Anthopleura elegantissima, and its dinoflagellate-algal symbiont Symbiodinium muscatinei was examined following laboratory metal exposures. Both, naturally occurring symbiotic and symbiont-free (aposymbiotic) anemones were used in this study to investigate differences in metal uptake due to the symbiotic state of the animal. The effects of metal exposures on the anemone-algal symbiosis were determined using measures of algal cell density and mitotic index (MI).

Seasonal variation in lysosomal destabilization in oysters, Crassostrea virginica.

Lysosomal destabilization assays have been used as valuable biomarkers of pollutant exposures in a variety of bivalve and fish species. The responses of oysters, Crassostrea virginica, deployed at and native to various reference and degraded sites were evaluated for lysosomal destabilization during both summer and winter seasons. In both native and deployed oysters, lysosomal destabilization rates tended to be higher during the winter at both reference and polluted sites.

Comparative in situ and laboratory sediment bioassays with juvenile Mercenaria mercenaria.

Sediment toxicity assays were conducted with juvenile Mercenaria mercenaria to compare the results of laboratory assays and in situ deployments. Juvenile clams were deployed for one week at a variety of degraded and undegraded sites in Charleston Harbor, South Carolina. USA, during the summers of 1998, 1999, and 2000.