bluuebunny/crossref_metadata_2025_split huggingface dataset:
A comparative study of molecular similarity, statistical, and neural methods for predicting toxic modes of action
Authors: Basak Subhash C , Grunwald Gregory D , Host George E , Niemi Gerald J , Bradbury Steven P 
Published: March 2010

Abstract
Quantitative structure–activity relationship (QSAR) models are routinely used in predicting toxicologic and ecotoxicologic effects of untested chemicals. One critical factor in QSAR-based risk assessment is the proper assignment of a chemical to a mode of action and associated QSAR. In this paper, we used molecular similarity, neural networks, and discriminant analysis methods to predict acute toxic modes of action for a set of 283 chemicals. The majority of these molecules had been previously determined through toxicodynamic studies in fish to be narcotics (two classes), electrophiles/proelectrophiles, uncouplers of oxidative phosphorylation, acetylcholinesterase inhibitors, and neurotoxicants. Nonempirical parameters, such as topological indices and atom pairs, were used as structural descriptors for the development of similarity-based, statistical, and neural network models. Rates of correct classification ranged from 65 to 95% for these 283 chemicals.
Inhibition of sex pheromone communications of Trichogramma brassicae (Hymenoptera) by the insecticide chlorpyrifos
Authors: Delpuech Jean-Marie , Froment Benoit , Fouillet Pierre , Pompanon François , Janillon Sonia , Boulétreau Michel 
Published: March 2010

Abstract
Biological control agents such as entomophagus insects (e.g., Trichogramma sp.) are important components of integrated pest management (IPM) programs. Because pesticides are also an important component of IPM programs, it is essential to understand how biological control agents are affected by pesticides and how these effects may affect the effectiveness of the biological control agents. Contrary to most insect species that use volatile pheromones for mate location, T. brassicae is one of the few species using a substrate-borne sex pheromone for mating. In this work we determined the effects of an organophosphorus insecticide, chlorpyrifos, on sex pheromone reception by males and emission by virgin females. The insects used in the pheromone tests were survivors from an acute toxicity test in which individuals were exposed to a dose of chlorpyrifos equivalent to a 20% lethal dose. Males that survived the insecticide exposure spent much less time on the area marked with the female pheromone than control males (mean choice indexes, 0.46 [0.34 SD] vs 0.70 [0.25 SD], p &lt; 0.001). The kinetics of the response of males to marking by control and treated females indicated that chlorpyrifos decreased the emission of sex pheromone by females surviving the insecticide. Therefore, chlorpyrifos inhibited pheromone reception by males and decreased pheromone emission by virgin females. These results are interpreted in the context of sex pheromone regulation by the nervous system of insects and according to the mode of action of chlorpyrifos. Extensions of these results on actual work on sex pheromone, the use of pheromone traps, and the population biology of Trichogramma sp. are discussed.
Edaphic factors affecting the toxicity and accumulation of arsenate in the earthworm Lumbricus terrestris
Authors: Meharg Andrew A , Shore Richard F , Broadgate Kirsten 
Published: March 2010

Abstract
The toxicity and accumulation of arsenate was determined in the earthworm Lumbricus terrestris in soil from different layers of a forest profile. Toxicity increased fourfold between 2 and 10 d. Edaphic factors (pH, soil organic matter, and depth in soil profile) also affected toxicity with a three fold decrease in the concentration that causes 50% mortality with increasing depth in soil (from 0–70 mm to 500–700 mm). In a 4-d exposure study, there was no evidence of arsenic bioconcentration in earthworm tissue, although bioaccumulation was occurring. There was a considerable difference in tissue residues between living and dead earthworms, with dead worms having higher concentrations. This difference was dependent on both soil arsenate concentration and on soil type. Over a wide range of soil arsenate concentrations, earthworm arsenic residues are homeostatically maintained in living worms, but this homeostasis breaks down during death. Alternatively, equilibration with soil residues may occur via accumulation after death. In long-term accumulation studies in soils dosed with a sublethal arsenate concentration (40 μg/g dry weight), bioconcentration of arsenate did not occur until day 12, after which earthworm concentrations rose steadily above the soil concentration, with residues in worms three fold higher than soil concentrations by the termination of the study (23 d). This bioconcentration only occurred in depurated worms over the time period of the study. Initially, depurated worms had lower arsenic concentrations than undepurated until tissue concentrations were equivalent to the soil concentration. Once tissue concentration was greater than soil concentration, depurated worms had higher arsenic residues than undepurated.
Experimental oiling of sanderlings (Calidris alba): Behavior and weight changes
Authors: Burger Joanna , Tsipoura Nellie 
Published: March 2010

Abstract
We applied fresh and weathered oil from the Anitra oil spill to the belly feathers of experimental sanderlings (Calidris alba) to simulate 20% plumage oiling, whereas controls were stroked with clean swabs only. We tested the null hypotheses that there were no differences in behavior following oiling and that there were no differences in weight gain or loss in control and experimental birds. Control sanderlings showed no differences in behavior before and after oiling, but oiled birds spent significantly less time resting and more time bathing and preening. Significant differences in weight and behavior were observed between the control and oiled birds. Following oiling, the sanderlings preened vigorously, spreading the oil so that they appeared to have oiling rates of 30%. Thereafter, the percentage of their plumage that was oiled decreased steadily over the next 2 weeks, but the birds never appeared completely free of oil.
Longevity and reproduction ofCeriodaphnia dubiain receiving waters
Authors: Stewart Arthur J , Konetsky Belinda K 
Published: March 2010

AbstractSeven-day tests with Ceriodaphnia dubia are commonly used to estimate toxicity of effluents or receiving waters but can sometimes yield no toxicity outcomes even if pollutants are present. We conducted two sets of full life-cycle tests with C. dubia to (1) determine whether tests with longer exposure periods to low concentrations of contaminants in ambient water might reveal evidence of toxicity that could not be discerned from 7-d tests and (2) determine the relative importance of water quality versus food as factors influencing C. dubia longevity and reproduction. In the first set of tests, C. dubia was reared in diluted mineral water (a negative control), water from a stream impacted by coal fly-ash, or water from a retention basin containing sediments contaminated with mercury, other metals, and polychlorinated biphenyls. The second set of tests used water from the retention basin only. Before testing, though, water in the second set of tests was either filtered or not filtered, and food was either added or not added. Ceriodaphnia dubia longevity and reproduction did not differ much among the three water types in the first set of tests, but both longevity and reproduction were strongly affected by the filtering and food-addition treatments in the second set of tests. Thus, C. dubia appeared to be relatively insensitive to general water quality factors but sensitive to food-related factors. In five of the six full life-cycle tests, lifetime reproduction by C. dubia could not be reliably predicted from reproduction data from the first 7 d of testing (R2 &lt; 0.35, by regression analysis). The increase in predictability of lifetime reproduction of C. dubia as a function of test duration also differed among water types in the first set of tests and among treatments in the second set of tests. Thus, it may not be possible to reliably extrapolate the results of 7-d tests with C. dubia to longer time scales.
Toxicity effects of organosulfur compounds on anaerobic microbial metabolism
Authors: Londry Kathleen L , Suflita Joseph M. 
Published: March 2010

Abstract
Four classes of organosulfur compounds were tested for their effects on anaerobic microbial activity as indicated by rates of lactate degradation, nitrate or sulfate reduction, and methanogenesis. Each class consisted of five to eight chemically related compounds that were added concurrently to anaerobic cultures established with an oily sludge inoculum. Effects on anaerobic activities were evaluated at different amounts of the chemicals and were concentration dependent in all cases. Thiophenes and thiols inhibited microbial activity under methanogenic conditions at ≥5 mmol/L; the former compounds had less effect under nitrate-reducing conditions, and the latter had less effect under sulfate-reducing conditions. Thiophenic acids did not influence most microbial processes at the lower concentrations tested (≤0.50 mmol/L). Aromatic sulfides were inhibitory to microbial activity under all three conditions at ≥5 mmol/L and had a greater effect on electron acceptor reduction than lactate oxidation. We conclude that the inhibitory effect of organosulfur compounds on microbial metabolism could potentially influence the assessment of anaerobic biodegradation activities in either the laboratory or anoxic environments.
Use of quantitative shape-activity relationships to model the photoinduced toxicity of polycyclic aromatic hydrocarbons: Electron density shape features accurately predict toxicity
Authors: Mezey Paul G , Zimpel Zbigniew , Warburton Peter , Walker P Duane , Irvine Donald G , Huang Xiag-Dong , Dixon D George , Greenberg Bruce M 
Published: March 2010

Abstract
The quantitative shape–activity relationship (QShAR) methodology, based on accurate three-dimensional electron densities and detailed shape analysis methods, has been applied to a Lemna gibba photoinduced toxicity data set of 16 polycyclic aromatic hydrocarbon (PAH) molecules. In the first phase of our studies, a shape fragment QShAR database of PAHs was developed. The results provide a very good match to toxicity based on a combination of the local shape features of single rings in comparison to the central ring of anthracene and a more global shape feature involving larger molecular fragments. The local shape feature appears as a descriptor of the susceptibility of PAHs to photomodification and the global shape feature is probably related to photosensitization activity.
Bioavailability and biodegradation of weathered diesel fuel in aquifer material under denitrifying conditions
Authors: Bregnard Thierry Pierre-Alain , Höhener Patrick , Zeyer Josef 
Published: March 2010

Abstract
During the in situ bioremediation of a diesel fuel-contaminated aquifer in Menziken, Switzerland, aquifer material containing weathered diesel fuel (WDF) and indigenous microorganisms was excavated. This material was used to identify factors limiting WDF biodegradation under denitrifying conditions. Incubations of this material for 360 to 390 d under denitrifying conditions resulted in degradation of 23% of the WDF with concomitant consumption of NO 3− and production of inorganic carbon. The biodegradation of WDF and the rate of NO 3− consumption was stimulated by agitation of the microcosms. Biodegradation was not stimulated by the addition of a biosurfactant (rhamnolipids) or a synthetic surfactant (Triton X-100) at concentrations above their critical micelle concentrations. The rhamnolipids were biodegraded preferentially to WDF, whereas Triton X-100 was not degraded. Both surfactants reduced the surface tension of the growth medium from 72 to &lt;35 dynes/cm and enhanced the apparent aqueous solubility of the model hydrocarbon n-hexadecane by four orders of magnitude. Solvent-extracted WDF, added at a concentration equal to that already present in the aquifer material, was also biodegraded by the microcosms, but not at a higher rate than the WDF already present in the material. The results show that the denitrifying biodegradation of WDF is not necessarily limited by bioavailability but rather by the inherent recalcitrance of WDF.
Distribution of alkylphenol compounds in great lakes sediments, United States and Canada
Authors: Bennett Erin R , Metcalfe Chris D 
Published: March 2010

Abstract
Alkylphenol polyethoxylates are a major class of nonionic surfactants that are microbially degraded in sewage treatment plants (STPs) and sediments to more toxic and hydrophobic alkylphenols. Recent data on the estrogenic activity of alkylphenols has prompted interest in the distribution of these compounds in the aquatic environment. Sediment samples were collected from several sites (n = 28) at industrialized and pristine regions of Lake Huron, Lake Erie, and Lake Ontario, USA and Canada, and analyzed for concentrations of 4-nonylphenol (NP) and 4-(tert)-octylphenol (OP). Also, sludge samples were taken from a secondary STP in Whitby, Ontario, Canada. Sediment and sludge samples and analytical standards were prepared for analysis by gas chromatography–mass spectrometry in selected ion mode by combined acetylation and supercritical fluid extraction. Concentrations of NP were up to 37 μg/g in sediments and &gt;300 μg/g in the sewage sludge. Concentrations of OP were up to 23 μg/g in sediment and 21 μg/g in the sewage sludge. These data indicate that alkylphenols are distributed widely in sediments in the lower Great Lakes. However, concentrations of NP were present at high (μg/g) levels only in sediments near urban and industrialized centers.
Impact of glufosinate-ammonium and bialaphos on the phytoplankton community of a small eutrophic northern lake
Authors: Faber Marvin J , Thompson Dean G , Stephenson Gerald R , Boermans Herman J 
Published: March 2010

Abstract
The impact of glufosinate-ammonium and bialaphos on the phytoplankton community in a shallow eutrophic lake ecosystem was investigated using in situ enclosures. Flow cytometry was used to size phytoplankton cells and sort them as live or dead, depending upon their chlorophyll a autofluorescence intensity. Flow cytometric analyses provided significantly (p &lt; 0.001) higher abundance estimates as compared to conventional microscopic analyses. At the highest treatment levels (10 mg/L), both herbicides caused a significant but transient reduction in live phytoplankton cells (days 3–14), which was particularly apparent in the small (1–2 and 2–3 μm) classes. Transient impacts on phytoplankton live cell abundances were mirrored by depression in dissolved oxygen content in the treated enclosures. At an application rate of 10 mg/L, abundance of smaller phytoplankton in the bialaphos-treated enclosures recovered more rapidly (14 d) than those in the glufosinate-ammonium–treated enclosures (49 d). For days of maximal impact, estimated median effect concentrations (EC50) for reduction of phytoplankton abundance ranged from 2.5 to 3.4 mg/L for glufosinate-ammonium and 3.3 to 8.1 mg/L for bialaphos, whereas estimates of concentration inducing 20% reductions in abundance (EC20; 0.9–1.2 and 1.6–4 mg/L, respectively) more closely approximated the expected environmental concentration (1 mg/L), assuming direct overspray into water bodies of 15-cm depth.
Age-dependent toxicity of diazinon and terbufos in european starlings (Sturnus vulgaris) and red-winged blackbirds (Agelaius phoeniceus)
Authors: Wolfe Marti F , Kendall Ronald J 
Published: March 2010

Abstract
Adult European starlings (Sturnus vulgaris) are more resistant to poisoning by organophosphorous (OP) pesticides than are other passerine birds. Nestling starlings, however, are sensitive to OP intoxication. Both adult and nestling red-winged blackbirds (Agelaius phoeniceus) are sensitive to OP toxicity and therefore may be a more representative model of the toxic response of passerine birds. The purpose of this study was to compare the toxicity ratio, as indicated by median lethal dose (LD50), of terbufos and diazinon in adult and nestling starlings and red-winged blackbirds, and to compare cholinesterase (ChE) inhibition between species and among age groups. Red-winged blackbirds are more sensitive to terbufos and diazinon intoxication than are European starlings, and the young of both species are more sensitive than the adults. When mortality is used as the endpoint, adult starlings are approximately 103 times less sensitive to terbufos intoxication than are 2-d-old starling chicks and 137 times less sensitive than adult red-wings. Adult red-wings were only 4.1 times less sensitive than 0 to 3-d-old red-wing chicks. Adult starlings were approximately 47 times less sensitive to diazinon toxicity than 2-d-old starling nestlings and 65 times less sensitive than adult redwings. Adult red-wings were 3.8 times less sensitive to diazinon than 0- to 3-d-old red-wing nestlings. Plasma and brain ChE activity was depressed in starling and red-wing adults in a dose-dependent fashion, but the relationship between dose, and plasma and brain ChE depression was more evident in some nestling age groups than in others. Baseline ChE activity cannot be invoked to explain the sensitivity difference between species. Baseline ChE activities in both brain and plasma increase with age in both species. These changes may account in part for the greater sensitivity of the young as compared to the adult.
Impact of 2,3,7,8-TCDD exposure on survival, growth, and behavior of ospreys breeding in Wisconsin, USA
Authors: Woodford James E , Karasov William H , Meyer Michael W , Chambers Laura 
Published: March 2010

AbstractOsprey (Pandion halieatus) eggs collected from areas (Castle Rock and Petenwell Flowages) 7 km downstream from two bleached-kraft mill facilities from 1992 to 1996 contained much higher levels of 2,3,7,8-tetrachlordibenzo-p-dioxin (range = 29 to 162 pg/g wet weight, n = 18) than eggs collected from two reference areas upstream (range = below detection limits to 23.8 pg/g, n = 15). Levels in eggs of the remaining planar halogenated hydrocarbon congeners and other nonplanar organochlorines were not statistically different between the contaminated and upstream areas (p &gt; 0.05). We placed eggs from the contaminated area into nests at both reference areas (group A) and eggs from the reference areas into nests at the contaminated area (group B). No significant differences in egg hatching or chick fledging rates were observed between these groups and nests left unmanipulated at both reference areas (group C) and the contaminated area (group D). Mass increase rates of chicks differed significantly (p = 0.03), with the highest rates from group C and the lowest rates from group B. This difference cannot be easily attributed to differences in parental nest attentiveness or food provisioning, which were greater at the contaminated area. We conclude that although current planar halogenated hydrocarbon exposure levels were not affecting hatching and fledging rates, they may have affected chick growth.
The functional integrity of northern leopard frog (Rana pipiens) and green frog (Rana clamitans) populations in orchard wetlands. II. Effects of pesticides and eutrophic conditions on early life stage development
Authors: Harris Megan L , Bishop Christine A , Struger John , Ripley Brian , Bogart James P 
Published: March 2010

AbstractPremetamorphic northern leopard frogs (Rana pipiens) and green frogs (Rana clamitans) were evaluated at seven wetland sites, four of which were within apple orchards, to determine if environmental conditions associated with orchard management in southern Ontario, Canada, affected frog early development. Synchronous with breeding events (May–July), embryos and tadpoles were exposed, in situ and in the laboratory, to study site pond water for 2 to 3 weeks. Six pesticides commonly applied in apple orchards (Guthion® 50WP, Imidan® 50WP, Thiodan® 50WP, Dithane® DG, Nova® 40W, and Basudin® 500EC) and technical grade diazinon were also evaluated for direct toxicity to green frogs using continuous and discontinuous toxicity tests. Embryos and larvae exhibited poor hatching success and survival at some orchard sites during in situ assays, but no specific water source produced consistently poor developmental success. Reduced tadpole growth occurred at several study sites, showing no clear distinction between reference and orchard sites. Despite the collection of substantial environmental data, only surface water temperature appeared to be correlated with growth rates. Basudin 500EC, technical grade diazinon, and Dithane DG caused mortality, deformities, or growth inhibition during early development at environmentally relevant concentrations (&lt;0.01 mg/L), whereas Imidan 50WP, Guthion 50WP, and Nova 40W produced survival or growth effects at much higher levels (5–10 mg/L). Dithane DG (mancozeb) was acutely toxic during prolonged exposures, and sublethal growth and deformity responses occurred at nominal concentrations greater than 0.01 mg/L. Diazinon was the most toxic to green frogs, with median lethal concentrations of 2.8 to 5 μg/L and median effective concentrations of 6 to 14 μg/L for formulation and technical grades, respectively. The combined results of in situ and laboratory tests of green frog and leopard frog developmental success suggested that embryo—larval development of these two species could be accomplished at all study sites, independent of the association with apple orchards.
Effects of azinphos-methyl on northern bobwhite: A comparison of laboratory and field results
Authors: Matz Angela C , Bennett Richard S , Landis Wayne G 
Published: March 2010

AbstractThe U.S. Environmental Protection Agency's (U.S. EPA's) ecological risk assessment process uses laboratory toxicity data in quotient indices to characterize risks to wildlife, but with poor understanding of the relationship between these data and actual field effects. To explore this relationship, we compared toxicity results from a controlled field study to those from a dietary toxicity (median lethal concentration) laboratory test. In the field test, northern bobwhite (Colinus virginianus) chicks were cross-fostered to bantam chicken (Gallus domesticus) hens. Then, 12-d-old broods in enclosed alfalfa fields were exposed to sprayed azinphos-methyl (Guthion® 2S) at three application rates (0 [control], 0.77, and 3.11 kg active ingredient/ha). Chick survival was significantly lower at 3.11 kg/ha 0 to 5 d postspray and at both application rates 6 to 10 d postspray compared to control (p &lt; 0.05). Chick brain acetylcholinesterase (AChE) activity, growth, and weight of crop contents were significantly reduced in treatments compared to control (p &lt; 0.05). In the laboratory test, 12-d-old bobwhite were exposed to dietary concentrations of 0 (control), 150, 240, 380, and 600 ppm azinphos-methyl for 5 d. Survival was significantly lower at 600 ppm compared to control, and brain AChE activity and growth rates were significantly reduced from control for all concentrations (p &lt; 0.05). Chick survival, brain AChE activity, and growth in the field were significantly different from equivalent exposures in the laboratory (p &lt; 0.05), with equivalency determined by U.S. EPA's vegetation residue estimates, and temporal patterns of effects differed between field and laboratory. We conclude that the effects observed in the field differed from that predicted by risk quotients because the quotient method does not consider alternate routes of exposure, behavioral responses, influence of spatial and temporal environmental variability, or indirect effects.