bluuebunny/crossref_metadata_2025_split huggingface dataset:
Detection of cytochrome P4501A in several species using antibody against a synthetic peptide derived from rainbow trout cytochrome P4501A1
Authors: Lin Song , Bullock Peter L , Addison Richard F , Bandiera Stelvio M 
Published: March 2010

Abstract
Induction of cytochrome P4501A (CYP1A) is being used increasingly as a biomarker to indicate exposure of organisms to environmental contaminants such as some polycyclic and polychlorinated aromatic hydrocarbons. Measurement of CYP1A protein in wildlife would be facilitated by the use of a specific antibody that recognized the isozyme in several species. In the present study, a polyclonal antibody targeted to CYP1A1 was generated using a synthetic peptide corresponding to amino acids 277–294 of the trout enzyme as the antigen of immunization. Specificity of the resulting antibody was assessed by noncompetitive enzyme-linked immunosorbent assay with several purified rat CYP isozymes and by immunoblot analysis with liver microsomes from diverse species. The antibody reacted strongly with the immunizing peptide and with purified rat cytochrome P4501A1 but did not react with rat CYP1A2, a closely related isozyme, or with six other purified rat CYP proteins in enzyme-linked immunosorbent assay. On immunoblots, the antibody recognized a single protein band in hepatic microsomes from the various mammal and fish species tested. Two protein bands were detected in liver microsomes from 3-methylcholanthrene-treated chickens. The results suggest that the antigenic determinant to which the antibody binds is unique to CYP1A and is conserved in different species. Because of its specificity, this anti-peptide antibody should be suitable as a probe to measure CYP1A protein levels in wildlife.
Sex-steroid and thyroid hormone concentrations in juvenile alligators (Alligator mississippiensis) from contaminated and reference lakes in Florida, USA
Authors: Crain D Andrew , Guillette Louis J , Pickford Daniel B , Percival H Franklin , Woodward Allan R 
Published: March 2010

Abstract
Sex-steroid and thyroid hormones are critical regulators of growth and reproduction in all vertebrates, and several recent studies suggest that environmental chemicals can alter circulating concentrations of these hormones. This study examines plasma concentrations of estradiol-17β (E2), testosterone (T), triiodothyronine (T3), and thyroxine (T4) in juvenile alligators (60–140 cm total length) from two contaminated lakes and one reference lake in Florida. First, the data were analyzed by comparing hormone concentrations among males and females from the different lakes. Whereas there were no differences in plasma E2 concentrations among animals of the three lakes, male alligators from the contaminated lakes (Lake Apopka and Lake Okeechobee) had significantly lower plasma T concentrations compared to males from the reference lake (Lake Woodruff). Concentrations of thyroid hormones also differed in animals of the three lakes, with T4 concentrations being elevated in Lake Okeechobee males compared to Lake Woodruff males. Second, the relationship between body size and hormone concentration was examined using regression analysis. Most notably for steroid hormones, no clear relationship was detected between E2 and total length in Apopka females (r2 = 0.09, p = 0.54) or between T and total length in Apopka males (r2 = 0.007, p = 0.75). Females from Apopka (r2 = 0.318, p = 0.09) and Okeechobee (r2 = 0.222, p = 0.09) exhibited weak correlations between T3 and total length. Males from Apopka (r2 = 0.015, p = 0.66) and Okeechobee (r2 = 0.128, p = 0.19) showed no correlation between T4 and total length. These results indicate: some of the previously reported abnormalities in steroid hormones of hatchling alligators persist, at least, through the juvenile years; steroid and thyroid hormones are related to body size in juvenile alligators from the reference lake, whereas alligators living in lakes Apopka and Okeechobee experience alterations in circulating thyroid and steroid hormones in relationship to body size; and a number of the hormone abnormalities reported previously for Lake Apopka alligators are observed in alligators from Lake Okeechobee—a lake associated with numerous contaminant sources but no major chemical spill. The endocrine alterations reported in this study are hypothesized to be a response to embryonic exposure to endocrine-disrupting contaminants.
Comparative toxicity of 2,3,7,8-tetrachlorodibenzo-p-dioxin to seven freshwater fish species during early life-stage development
Authors: Elonen Gregory E , Spehar Robert L , Holcombe Gary W , Johnson Rodney D , Fernandez Joseph D , Erickson Russell J , Tietge Joseph E , Cook Philip M 
Published: March 2010

AbstractThe toxic effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) to fathead minnow (Pimephales promelas), channel catfish (Ictalurus punctatus), lake herring (Coregonus artedii), medaka (Oryzias latipes), white sucker (Catastomus commersoni), northern pike (Esox lucius), and zebrafish (Danio danio) were observed during early life-stage development after waterborne exposure of fertilized eggs. Species sensitivity based on TCDD-Cegg (TCDD concentration in eggs) was determined by effects observed over a 32-d period for all species except lake herring in which a 100-d period was used. Signs of TCDD toxicity, including edema, hemorrhaging, and craniofacial malformations were essentially identical to those observed in salmonids following TCDD egg exposure and preceded or accompanied mortality most often during the period from hatch through swim-up. The no-observed-effect concentrations and lowest-observed-effect concentrations, based on significant decreases in survival and growth as compared to the controls, ranged from 175 and 270 pg/g for lake herring to 424 and 2,000 pg/g for zebrafish, respectively. Shapes of concentration–response curves, expressed as TCDD-Cegg versus percent mortality, were similar for all species and were consistently steep suggesting that the mechanism of action of TCDD is the same among these species. The LCegg50s (concentrations in eggs causing 50% lethality to fish at test termination) ranged from 539 pg/g for the fathead minnow to 2,610 pg/g for zebrafish. Comparisons of LCegg50s indicate that the tested species were approximately 8 to 38 times less sensitive to TCDD than lake trout, the most sensitive species evaluated to date. When LCegg50s are normalized to the fraction lipid in eggs (LCegg,l50s), the risk to early life stage survival for the species tested ranges from 16- to 180-fold less than for lake trout.
Kinetics and conductivity parameters of uptake and transport of polychlorinated biphenyls in the Caco-2 intestinal cell line model
Authors: Dulfer Wiegert J , Govers Harrie A J , Groten John P 
Published: March 2010

Abstract
Most of the accumulation of polychlorinated biphenyls (PCBs) over the food chain can be attributed to contaminant uptake from food. The effect of fatty acid absorption on net uptake and transport fluxes of a selection of 14 PCBs over the organismal gut epithelium has been determined in monolayers of the colon carcinoma cell line Caco-2 as a model system. The thermodynamic fugacity approach and the physiology of enterocyte lipid digestion are combined to investigate gastrointestinal absorption of polychlorinated biphenyls. The resistances of the subsequent transport steps from the apical compartment through the enterocytes to the basolateral compartment were quantified in terms of conductivity parameters. During uptake of PCBs into the enterocytes, the resistance of the aqueous diffusion barrier adjacent to the brush-border membrane is overcome for more than 99% by means of micellar transport. In the interior of the cells, the aquatic cytoplasm compartment also provides an important route of transport to the PCBs with up to three chlorine atoms, but the more hydrophobic PCBs are preferentially transported by triglyceride particles and lipoproteins. Calculated triolein/water partition coefficients, Ktri, in general are higher than taurocholate micelle/water, dimyristoylphosphatidylcholine membrane/water and n-octanol/water partition coefficients, KTC, KDMPC, and Kow, respectively. Calculations suggest that the correlation between log Kow and log Ktri is nonlinear.
Effect of chemical synergy and larval stage on the toxicity of atrazine and alachlor to amphibian larvae
Authors: Howe George E , Gillis Rick , Mowbray Rodney C 
Published: March 2010

Abstract
We determined the acute toxicity of field-grade formulations of atrazine, alachlor, and a 50:50 mixture of the chemicals to early and late larval stages of northern leopard frogs (Rana pipiens) and American toads (Bufo americanus). We conducted identical tests with rainbow trout (Onchorhynchus mykiss) and channel catfish (Ictalurus punctatus) to compare their sensitivity as bioindicators. The acute toxicity (96-h median lethal concentrations [LC50s]) of herbicides to amphibian larvae ranged from 47.6 mg/L for early-stage R. pipiens exposed to atrazine to 3.3 mg/L for late-stage B. americanus exposed to alachlor. The toxicity of a 50:50 mixture of atrazine and alachlor after a 96-h exposure was greater than additive (chemical synergy present) for most species and life stages tested, with 96-h LC50s as low as 1.5 mg/L for late-stage B. americanus larvae. Older amphibian larvae appeared to be more sensitive than younger larvae for both species and chemicals tested. Overall, rainbow trout and channel catfish appeared to be less sensitive than amphibian larvae. The 96-h LC50s ranged from 23.8 mg/L for channel catfish exposed to atrazine to 9.1 mg/L for rainbow trout exposed to alachlor. A noteworthy sublethal effect observed in amphibian larvae exposed to atrazine was edema, probably caused by renal disfunction. Chronic predicted no-observed-effect concentrations (PNOECs) for lethality after a 30-d exposure were estimated from mortality data at 3, 6, 24, 48, 72, and 96 h and found to be approximately 10- to 20-fold lower than 96-h LC50s. The calculated PNOECs are close enough to concentrations actually found in the environment to warrant concern and further tests. Additional research on environmental concentrations, chronic effects, and the effects of chemical synergy is needed before definitive conclusions can be drawn. Chemical synergy and life-stage sensitivity should be addressed to properly assess the toxicity of herbicides to nontarget organisms.
Individual-based risk estimation for count responses
Authors: Bailer A John , See Kyoungah 
Published: March 2010

AbstractAn individual-based risk assessment strategy is developed and presented for count responses as are commonly encountered in reproductive toxicology experiments. This strategy is predicated on the availability of a fitted concentration–response regression model. Adverse response is defined in terms of the production of young being suppressed below a certain specified level. The probability of this adverse response is defined in light of the concentration–response regression model. Added risk, the probability of adverse response in individuals exposed to a particular concentration condition relative to the probability of adverse response in unexposed organisms, serves as the basis of the individual-based risk estimation procedures. In particular, estimates of the added risk associated with a specified concentration and the concentration associated with a specified level of added risk are presented. Confidence intervals are developed for these two statistical endpoints using the delta method. These ideas are illustrated with two studies of Ceriodaphnia dubia exposed to nitrofen and atrazine.
Toxicity of silver to the marine teleost (Oligocottus maculosus): Effects of salinity and ammonia
Authors: Shaw Joseph R , Wood Chris M , Birge Wesley J , Hogstrand Christer 
Published: March 2010

AbstractInvestigations were conducted to determine the toxicity and define parameters (i.e., ammonia, salinity) that influence the effects of silver on the tidepool sculpin (Oligocottus maculosus). In one series of experiments, static-renewal 168-h toxicity tests were conducted with silver at 32‰(i.e., ambient) and 25‰ salinity seawater. Silver was analyzed in fish that survived these exposures. Toxicity was greater at the lower salinity. The 96-h and 168-h 50% lethal concentration (LC50) values were 3.07 μmol Ag/L (0.331 mg Ag/L) and 1.11 μmol Ag/L (0.119 mg Ag/L) at 25‰ and 6.2 μmol Ag/L (0.664 mg Ag/L) and 4.37 μmol Ag/L (0.472 mg Ag/L) at 32‰ salinity, respectively. There was no correlation between whole-body silver burden and toxicity. Silver uptake increased with exposure concentrations at 25‰ salinity, but at 32‰ whole body accumulation did not exceed that observed for control fish irrespective of the concentrations tested. In another set of experiments, 96-h static-renewal toxicity tests were conducted with silver, ammonia, and combinations of each. The 96-h LC50 for ammonia was 5.9 mmol total ammonia (Tamm)/L (106 mg Tamm/L). When tested in combination, silver toxicity was enhanced and the onset of mortality hastened. Mortality increased in a dose-dependent fashion at 6.35 μmol Ag/L (0.685 mg Ag/L) from 55 to 100% in the presence of ammonia concentrations ranging from 0 to 12.60 mmol Tamm/L (0–226.8 mg Tamm/L). Conversely, the 50% lethal time (LT50) estimated at this level of silver exposure progressively dropped from 5,730 to 1,180 min over the same range of ammonia concentrations.
Bioaccumulation of silver from laboratory-spiked sediments in the oligochaete (Lumbriculus variegatus)
Authors: Hirsch Marianne P 
Published: March 2010

AbstractA 28-d bioaccumulation study was conducted to assess the potential of silver to bioaccumulate in the oligochaete Lumbriculus variegatus. The oligochaetes were exposed to laboratory-spiked sediments containing approx. 444 mg Ag/kg dry weight for up to 28 d. Fifteen test replicates were prepared by adding 300 adult L. variegatus to 4-L glass beakers containing 1 L of silver sulfide-amended sediment. An equal number of controls were also prepared. After 1, 5, 13, 21, and 28 d of exposure to the sediments, the oligochaetes within each of three test and three control replicate vessels were recovered and counted. The recovered organisms were transferred to dilution water and allowed to purge gut contents for 24 h. The organisms recovered from each replicate vessel at each sampling period were pooled, dried, weighed, and analyzed to determine tissue silver concentrations. By the end of the test, the mean number of oligochaetes recovered from the control and the test sediments increased by 1.8- and 1.9-fold, respectively. The accumulation factor for silver, as silver sulfide, was estimated to be 0.18. This low accumulation factor indicates that contamination of sediments with silver sulfide does not pose a major route of entry of silver into the aquatic food web.
Halogenation and toxicity of the biodegradation products of a nonionic surfactant, nonylphenol ethoxylate
Authors: Maki Hideaki , Okamura Hideo , Aoyama Isao , Fujita Masanori 
Published: March 2010

Abstract
We simulated the formation of halogenated by-products of biodegradation products of a nonionic surfactant, nonylphenol ethoxylate (NPE), and evaluated the toxicity of these by-products. Most NPE derivatives bearing shortened ethylene oxide (EO) chains (abbreviated as NPnEO) and nonylphenol carboxylate (NPnEC) disappeared within 24 h. In both NPnEO and NPnEC, benzene rings are substituted by monobromine. In contrast, chlorine-substituted derivatives were scarcely detected. However, the stoichiometrical bromination of NPnEO and NPnEC was not found. Total amounts of NPnEO, NPnEC, and their bromine-substituted products (BrNPnEO and BrNPnEC, respectively) tended to diminish with increasing level of residual chlorine concentration. Hence, it was suggested that both NPnEO and NPnEC were transformed to unknown by-products. The optimum pH for the formation of both BrNPnEO and BrNPnEC was approximately 7, and these formations decreased remarkably at higher pH. The formation of both BrNPnEO and BrNPnEC was shown to be dependent on the bromide anion concentration but independent of the level of residual chlorine. In the umu assay, a mutagenicity test that uses genetically engineered Salmonella bacteria, neither BrNPnEO nor BrNPnEC showed significant mutagenicity irrespective of metabolic activation by S9-mix. However, both BrNPnEO and BrNPnEC showed higher acute toxicity to Daphnia magna than their nonbrominated precursors, NPnEO and NPnEC. The toxicity of BrNPnEO to Daphnia was higher than that of BrNPnEC.
Sensitivity limits and EC50 values of theVibrio fischeritest for organic micropollutants in natural and spiked extracts from sediments
Authors: Salizzato Michela , Bertato Valentina , Pavoni Bruno , Ghirardini Anna Volpi , Ghetti Pier Francesco 
Published: March 2010

AbstractChemical analyses and bioassays were used in conjunction to assess the quality of sediments of the Venice lagoon. Organic micropollutants (polycyclic aromatic hydrocarbons [PAHs] polychlorinated biphenyls [PCBs], and chlorinated pesticides) were extracted from sediment samples and analyzed by gas chromatography after fractionation into classes of compounds. The Vibrio fischeri test was used to assess the acute toxicity of sediment extracts. The test was applied to organic extracts before cleanup and to extracts purified from sulfur and fractionated into single classes of compounds. Extracts before purification were much more toxic than single fractions. In particular, sulfur was toxic to V. fischeri. For PAHs and PCBs the 50% effective concentration (EC50) and EC20 values were determined using natural and spiked extracts (EC50 = 0.5 μg/ml and 1.4 μg/ml, respectively; EC20 = 0.13 μg/ml and 0.17 μg/ml). Sensitivity limits of the method for these compounds were also estimated as was an EC50 value of elemental sulfur dissolved in ethanol (0.022 μg/ml). A mathematical model was used to fit the concentration–response data to a sigmoid curve.
Tentative identification of persistent poly(glycidyl) monofluorooctylphenyl ether nonionic surfactant in river waters and effluent from a secondary wastewater treatment plant
Authors: Yamagishi Tomohiko , Hashimoto Shinya , Otsuki Akira 
Published: March 2010

Abstract
Water samples were collected at two polluted rivers and near the discharge mouth of a large secondary wastewater treatment plant in Tokyo. After surfactants in filtrates were adsorbed onto Amberlite XAD-16 resin and eluted with methanol, the co-adsorbed anionic and cationic surfactants in the eluent were removed with a strong cation- and anion-exchange resin column. Poly(oxyethylene) octylphenyl ether nonionic surfactant was separated using normal-phase high-performance liquid chromatography (HPLC) with UV detection at 280 nm and a pure carbon column after concentration of the eluent by nitrogen gas stream. A relatively large unknown peak in the HPLC chromatogram was fractionated and an attempt was made to identify it by atmospheric pressure chemical ionization and electrospray ionization mass spectrometry. The present study tentatively identified the occurrence of persistent poly(glycidyl) monofluorooctylphenyl ether nonionic surfactants as one of the new persistent organic pollutants in river waters and effluent from a secondary wastewater treatment plant.
Biomonitoring with shrimp to detect seasonal change in river water toxicity
Authors: Shigehisa Hatakeyama , Shiraishi Hiroaki 
Published: March 2010

AbstractSeasonal changes in toxicity of Kokai River water to a freshwater shrimp (Paratya compressa improvisa) were monitored from 1989 to 1993. A 4-d toxicity test was conducted three times a week from April to August from 1989 to 1993 to measure mortality. Seventeen pesticides were analyzed during the biological monitoring. Expected shrimp mortalities were calculated by adding mortalities caused by each insecticide at the measured concentrations. Shrimp mortalities increased in late May to mid-June and could be attributed to additive effects of insecticides such as pyridaphenthion, malathion, and fenobucarb. Mortalities decreased toward the end of June but increased again from July to mid-August and could be attributed to insecticides such as diazinon or fenobucarb, which drifted directly into the river after aerial pesticide spraying on paddy fields. High mortalities decreased rapidly after heavy rains in August.
Bioavailability of methylmercury to sacramento blackfish (Orthodon microlepidotus): Dissolved organic carbon effects
Authors: Choi Monica Heekyoung , Cech Joseph J , Lagunas-Solar Manuel C 
Published: March 2010

Abstract
The effect of dissolved organic carbon (DOC) on methylmercury (MeHg) uptake across the gills of Sacramento blackfish (Orthodon microlepidotus) was investigated using the Hg-203 radioisotope (half life = 46.9 d). The efficiency of fish gills in extracting MeHg (1.4 ng/L) from water was measured using a McKim-type fish respirometer that separated exposure (inspired) water from expired water. Blackfish gill ventilation and oxygen consumption rates remained constant, while Me203Hg uptake was decreased significantly (p &lt; 0.05) in the presence of DOC (2 and 5 mg C/L). Mean Me203Hg extraction efficiency, uptake rate constant, and blood to inspired water ratio decreased 78%, 73%, and 63%, respectively, with 2 mg C/L of DOC, and 85%, 82%, and 70% with 5 mg C/L DOC, compared to the Me203Hg reference treatment group. Because respiratory parameters remained unchanged, reductions in Me203Hg uptake indicate strong interactions between DOC and Me203Hg. Methyl203Hg levels in fish gills, kidney, and spleen from 2 and 5 mg C/L were significantly lower (p &lt; 0.05) than those observed from the reference treatment group. These reductions in uptake (bioavailability) support the hypothesis that trans-gill transport of Me203Hg is inhibited when it is complexed by DOC in the aqueous medium, decreasing Me203Hg uptake and accumulation in fish organs.
Response of vegetation to volatile pollutants: A delivery system for controlled, quantifiable chronic exposure of foliage
Authors: Love Sean D , Hale Beverley A 
Published: March 2010

Abstract
Little is known about air-to-foliage transfer of volatile organic pollutants: sink strength of leaves and toxicity to the plant via this route have not been widely documented. An exposure system that is capable of repeatedly delivering a range of concentrations of volatilized organic pollutant to foliage under optimal growth and activity conditions is needed. Using naphthalene (a polycyclic aromatic hydrocarbon) as a model contaminant, a steady-state exposure system was developed in which a continuous stream of naphthalene vapor was generated from a chilled permeation tube. This stream was proportionately released into four separate clean airstreams to deliver four discrete concentrations of naphthalene vapor to large cuvettes in which potted plants were sealed. Each cuvette received a total flow rate of 5 L/min. Naphthalene concentration exiting the permeation tube was calculated twofold: using ideal gas laws and from the daily mass loss of the permeation tube. Daily mass loss from the permeation tube and indirect indication of naphthalene concentration by UV light attenuation indicated that the exposure system was capable of maintaining a logarithmic range of naphthalene vapor concentrations over 4 d. Deviation from predicted concentrations was associated with high moisture content of the air supply line used to vent the permeation tube.