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Larval oysters are sensitive to thin oil sheens at environmentally relevant concentrations of PAHs.
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Oil sheen toxicity increases with UV light exposure.
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Short term exposure led to latent ...effects on oyster survival and swimming ability.
The Eastern oyster (
Crassostrea virginica)
is an important commercial bivalve species which also has numerous ecological roles including biogeochemical cycling, providing habitat for larval fish and crustaceans, and reducing the impacts of coastal storms. Oil may pose a threat to oyster larvae swimming in the water column, leading to potential negative effects on survival, growth, and development. Oil toxicity may be further enhanced by chemical changes in the presence of sunlight. This study determined the toxicity of thin oil sheens with and without ultraviolet (UV) light, then examined the latent effects of the short term exposure on longer term survival and swimming ability. Larval
C. virginica
were exposed to four different oil sheen thicknesses for 24 h with either no UV light or 2-h UV light. Following the exposure, larvae were transferred to clean seawater and no UV light for 96 h. The presence of a 2-h UV light exposure significantly increased oyster mortality, indicating photo-enhanced toxicity. The LC
50
for a 24-h oil sheen exposure without UV was 7.26 µm (23 µg/L PAH
50
) while a 2 h-UV exposure lowered the sheen toxicity threshold to 2.67 µm (10 µg/L PAH
50
). A previous 24-h oil sheen exposure (≥0.5 µm) led to latent effects on larval oyster survival, regardless of previous UV exposure. Sublethal impacts to larval oyster swimming behavior were also observed from the previous oil sheen exposure combined with UV exposure. This study provides new data for the toxicity of thin oil sheens to a sensitive early life stage of estuarine bivalve.
Chemical dispersants can be a useful tool to mitigate oil spills. This study examined potential risks to sensitive estuarine species by comparing the toxicity of two dispersants (Corexit
®
EC9500A ...and Finasol
®
OSR 52) individually and in chemically enhanced water-accommodated fractions (CEWAFs) of Louisiana Sweet Crude oil. Acute toxicity thresholds and sublethal biomarker responses were determined in seven species (sheepshead minnow, grass shrimp, mysid, amphipod, polychaete, hard clam, mud snail). Comparing median lethal (LC
50
) values for the dispersants, Finasol was generally more toxic than Corexit and had greater sublethal toxicity (impaired embryonic hatching, increased lipid peroxidation, decreased acetylcholinesterase activity). The nominal concentration-based mean LC
50
for all species tested with Corexit was 150.31 mg/L compared with 43.27 mg/L with Finasol. Comparing the toxicity of the CEWAFs using the nominal concentrations (% CEWAF), Corexit-CEWAFs appeared more toxic than Finasol-CEWAFs; however, when LC
50
values were calculated using measured hydrocarbon concentrations, the Finasol-CEWAFs were more toxic. There was greater dispersion efficiency leading to greater hydrocarbon concentrations measured in the Corexit-CEWAF solutions than in equivalent Finasol-CEWAF solutions. The measured concentration-based mean LC
50
values for all species tested with Corexit-CEWAF were 261.96 mg/L total extractable hydrocarbons (TEH) and 2.95 mg/L total polycyclic aromatic hydrocarbons (PAH), whereas the mean LC
50
values for all species tested with Finasol-CEWAF were 23.19 mg/L TEH and 0.49 mg/L total PAH. Larval life stages were generally more sensitive to dispersants and dispersed oil than adult life stages within a species. These results will help to inform management decisions regarding the use of oil-spill dispersants.
Lymphomas express a tumor-specific antigen which can be targeted by cancer vaccination. We evaluated the ability of a new idiotype protein vaccine formulation to eradicate residual t(14;18)+ lymphoma ...cells in 20 patients in a homogeneous, chemotherapy-induced first clinical complete remission. All 11 patients with detectable translocations in their primary tumors had cells from the malignant clone detectable in their blood by PCR both at diagnosis and after chemotherapy, despite being in complete remission. However, 8 of 11 patients converted to lacking cells in their blood from the malignant clone detectable by PCR after vaccination and sustained their molecular remissions. Tumor-specific cytotoxic CD8+ and CD4+ T cells were uniformly found (19 of 20 patients), whereas antibodies were detected, but apparently were not required for molecular remission. Vaccination was thus associated with clearance of residual tumor cells from blood and long-term disease-free survival. The demonstration of molecular remissions, analysis of cytotoxic T lymphocytes against autologous tumor targets, and addition of granulocyte-monocyte colony-stimulating factor to the vaccine formulation provide principles relevant to the design of future clinical trials of other cancer vaccines administered in a minimal residual disease setting.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Aim
To quantify evolutionary transitions between tropical evergreen rain forest and seasonally dry biomes, to test whether biome transitions affect lineage diversification and to examine the ...robustness of these results to methodological choices.
Location
The tropics.
Time period
The Cenozoic.
Major taxa studied
The plant subfamily Bombacoideae (Malvaceae).
Methods
We inferred ancestral biomes based on a fossil‐dated molecular phylogeny of 103 species (59% of the clade) and recorded the number of transitions among biomes using biogeographical stochastic mapping based on the dispersal‐extinction‐cladogenesis model. We then estimated diversification rates using state‐specific speciation and extinction rate (SSE) methods. Furthermore, we tested the sensitivity of the results to model choice, phylogenetic uncertainty, measurement error and biome definition.
Results
We found numerous transitions from evergreen rain forest to seasonally dry biomes, and fewer in the opposite direction. These results were robust to methodological choices. Biome type did not influence diversification rates, although this result was subject to uncertainty, especially related to model choice and biome definition.
Main conclusions
Our results contradict the idea of evolutionary biome conservatism in Bombacoideae, and support previous findings that evergreen rain forests serve as a source for the flora of seasonally dry biomes. The impact of biome classification and biome definition on the results suggest caution when using a biome concept for biogeographical reconstruction and diversification rate analysis.
Resolving the phylogenetic relationships of the deep nodes of papilionoid legumes (Papilionoideae) is essential to understanding the evolutionary history and diversification of this economically and ...ecologically important legume subfamily. The early-branching papilionoids include mostly Neotropical trees traditionally circumscribed in the tribes Sophoreae and Swartzieae. They are more highly diverse in floral morphology than other groups of Papilionoideae. For many years, phylogenetic analyses of the Papilionoideae could not clearly resolve the relationships of the early-branching lineages due to limited sampling. In the eight years since the publication of Legumes of the World, we have seen an extraordinary wealth of new molecular data for the study of Papilionoideae phylogeny, enabling increasingly greater resolution and many surprises. This study draws on recent molecular phylogenetic studies and a new comprehensive Bayesian phylogenetic analysis of 668 plastid matK sequences. The present matK phylogeny resolves the deep-branching relationships of the papilionoids with increased support for many clades, and suggests that taxonomic realignments of some genera and of numerous tribes are necessary. The potentially earliest-branching papilionoids fall within an ADA clade, which includes the recircumscribed monophyletic tribes Angylocalyceae, Dipterygeae, and Amburanae. The genera Aldina and Amphimas represent two of the nine main but as yet unresolved lineages comprising the large 50-kb inversion clade. The quinolizidine-alkaloid-accumulating Genistoid s.l. clade is expanded to include Dermatophyllum and a strongly supported and newly circumscribed tribe Ormosieae. Sophoreae and Swartzieae are dramatically reorganized so as to comprise monophyletic groups within the Core Genistoid clade and outside the 50-kb inversion clade, respectively. Acosmium is excluded from the Genistoids s.l. and strongly resolved within the newly circumscribed tribe Dalbergieae. By providing a better resolved phylogeny of the earliest-branching papilionoids, this study, in combination with other recent evidence, will lead to a more stable phylogenetic classification of the Papilionoideae.
Vibrio parahaemolyticus is a Gram negative, halophilic bacterium that is ubiquitous in warm, tropical waters throughout the world. It is a major cause of seafood-associated gastroenteritis and is ...generally associated with consumption of raw or undercooked seafood, especially oysters. This study presents a snapshot of total V. parahaemolyticus densities in surface waters and shellstock American oysters (Crassostrea virginica) from open and closed shellfish harvesting areas, as well as “more rural areas” on two different US coasts, the Atlantic and the Gulf. Sampling was conducted from 2001 to 2003 at five sites near Charleston/Georgetown, SC and at four locations in the Gulfport/Pascagoula, MS area. V. parahaemolyticus numbers were determined by a direct plating method using an alkaline-phosphatase-labeled DNA probe targeting the species-specific thermolabile hemolysin gene (tlh) that was used for identification of bacterial isolates. The greatest difference between the two coasts was salinity; mean salinity in SC surface waters was 32.9 ppt, whereas the mean salinity in MS waters was 19.2 ppt, indicating more freshwater input into MS shellfish harvesting areas during the study period. The mean V. parahaemolyticus numbers in oysters were almost identical between the two states (567.4 vs. 560.1 CFU/g). Bacterial numbers in the majority of surface water samples from both states were at or below the limit of detection (LOD = <10 CFU/mL). The bacterial concentrations determined during this study predict a low public health risk from consumption of oysters in shellfish growing areas on either the Gulf or the Atlantic US coast.
To examine the effects of environmentally realistic fipronil concentrations on estuarine ecosystems, replicated mesocosms containing intact marsh plots and seawater were exposed to three treatments ...of fipronil (150, 355, and 5000
ng/L) and a Control. Juvenile fish (
Cyprinidon variegatus), juvenile clams (
Mercenaria mercenaria), oysters (
Crassostrea virginica), and grass shrimp (
Palaemonetes pugio) were added prior to fipronil in an effort to quantify survival, growth, and the persistence of toxicity during the planned 28-day exposure. Results indicated that there were no fipronil-associated effects on the clams, oysters, or fish. Shrimp were sensitive to the highest two concentrations (40% survival at 355
ng/L and 0% survival at 5000
ng/L). Additionally, the highest fipronil treatment (5000
ng/L) was toxic to shrimp for 6 weeks post dose. These results suggest that fipronil may impact shrimp populations at low concentrations and further use in coastal areas should be carefully assessed.
Fluoxetine (FLX) is a selective serotonin reuptake inhibitor and is among the top 100 drugs prescribed yearly in the United States and the United Kingdom. Tissue and water extraction methods were ...developed to detect and quantify FLX, norfluoxetine and the associated biological compounds serotonin (5-HT), 5-hydroxyindole-3-acetic acid (5-HIAA), tryptophan (TRP) and melatonin (MEL) using LC/MS/MS. Acute mortality and sublethal physiological effects of FLX were assessed using standard static renewal toxicity tests in which juvenile sheepshead minnows (
Cyprinodon variegatus) were exposed to FLX. Fluoxetine did not cause significant mortality at levels near currently reported environmental concentrations. Significant changes in neurotransmitter levels were observed within the serotonergic system in juvenile sheepshead minnows exposed at concentrations approximately one order of magnitude above those currently reported in the environment. Transformation activity ratios of a product to a precursor compound (5-HT/TRP, 5-HIAA/5-HT and MEL/5-HT) also exhibited significant changes with FLX treatment. Fluoxetine exposure did not only affect 5-HT but had additional effects both upstream and downstream of 5-HT within its synthesis and metabolic pathways. These sublethal changes within the serotonergic pathway may result in behavioral changes which could, in turn, have implications for the ecological response of populations to additional environmental stressors.
Agricultural pesticide runoff in southeastern coastal regions of the United States is a critical issue. Bioconcentration of pesticides by phytoplankton and zooplankton at the base of the aquatic food ...web may increase the persistence of pesticides in aquatic ecosystems and cause effects at higher trophic levels. This study examined the toxicity of a widely used agricultural pesticide, endosulfan, to Pseudokirchneriella subcapitatum (freshwater green alga) and Daphnia magna (freshwater cladoceran). We then investigated the potential of both plankton species to sequester endosulfan from their surrounding media. We also assessed the degree to which endosulfan is accumulated by D. magna via food (endosulfan-contaminated P. subcapitatum). A 96-h growth rate EC50 of 427.80 microg/L endosulfan was determined for P. subcapitatum, whereas a 24-h immobilization EC50 of 366.33 microg/L endosulfan was determined for D. magna. The 5-h EC50s for filtration and ingestion in D. magna were 165.57 microg/L and 166.44 microg/L, respectively. An average bioconcentration factor (BCF) of 2,682 was determined for P. subcapitatum exposed to 100 microg/L endosulfan for 16 h. An average BCF of 3,278 was determined for D. magna in a 100 microg/L endosulfan water-only exposure. There was negligible uptake of endosulfan by D. magna feeding on contaminated algae in clean water (BCF approximately 0). Different proportions of parent isomers (endosulfan I and II) and the primary degradation product (endosulfan sulfate) were detected among treatments. Endosulfan was rapidly accumulated and concentrated from water by P. subcapitatum and D. magna neonates. Endosulfan contained in phytoplankton, however, was not bioaccumulated by zooplankton. These findings may prove useful in assessing ecosystem risk, because uptake from the water column appears to be the dominant route for bioconcentration of endosulfan by zooplankton.
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