bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of linear alkylbenzene sulfonates on functional diversity of microbial communities in soil
Authors: Vinther Finn P. , Mortensen Gerda K. , Elsgaard Lars 
Published: March 2010

AbstractLinear alkylbenzene sulfonates (LAS) often occur in sewage sludge that is applied to agricultural soil. Here LAS may affect the microbial activity, which is an important basis for nutrient cycling. Previous studies have shown that single bacterial species and specific soil processes can be very sensitive to LAS. Here we report that two levels of LAS, 22 and 174 mg/kg dry weight soil, had little or no significant influence of the functional diversity of bacteria in a sandy soil, as tested by community-level physiological profiles. Briefly, these profiles are a characterization of the microbial communities based on the pattern of substrate utilization in 96-well microtiter plates (Biolog EcoPlates). Sandy agricultural soil was incubated in duplicate 1-L mesocosms with or without LAS, and bacteria were extracted after one, two, and four weeks. During incubation, more than 98 and 93% of LAS added to 22 and 174 mg/kg dry weight soil was degraded, respectively. The presence of LAS at 174 mg/kg dry weight caused a higher number of bacteria in the soil extracts, maximally corresponding to 2.5 times the numbers in LAS-free soil (1.8 × 107 cells/g dry wt soil) after four weeks of incubation. No inhibitory effect of LAS was observed when the substrate utilization data were analyzed for substrate richness and diversity (Shannon-Weaver indices). Principal component analysis, however, showed that the pattern of substrate utilization in soil with the highest LAS content (174 mg/kg dry wt) could be distinguished from control soil and soil with 22 mg LAS/kg dry weight. Yet the overall conclusion was that the functional diversity of the aerobic, heterotrophic bacterial community was rather insensitive to LAS.
Determination of polycyclic aromatic hydrocarbons in dungeness crabs (Cancer magister) near an aluminum smelter in Kitimat Arm, British Columbia, Canada
Authors: Eickhoff Curtis V. , He Shao-Xiong , Gobas Frank A. P. C. , Law Francis CP. 
Published: March 2010

Abstract
An aluminum smelter situated at the head of Kitimat Arm (BC, Canada) has discharged polycyclic aromatic hydrocarbons (PAHs) into the receiving waters since 1954. The purpose of the present study was to examine the distribution of PAHs contaminants in dungeness crabs (Cancer magister) collected in Kitimat Arm and Douglas Channel (BC, Canada) by determining the concentrations of PAHs in the hepatopancreas and muscle tissues of crabs by using gas chromatography-mass spectrometry. Crabs were collected at specific sites down the Arm from the smelter on four separate occasions over a three-year period. Hepatopancreas and muscle tissues of the crabs were analyzed for 10 of the 16 PAH priority pollutants recommended by the U.S. Environmental Protection Agency. Results of the studies showed that the crabs had detectable levels of PAHs in hepatopancreas and muscle tissues. The highest concentrations of PAHs in the tissues were found at a site near the aluminum smelter, the alleged point source of PAH discharge. The concentrations of PAH analytes were high in crabs collected close to the smelter and at lower levels in crabs collected throughout Douglas Channel. These results show that PAHs discharged by the smelter were bioavailable to the crabs. The concentration of each PAH analyte in the hepatopancreas was found to be strongly related to its water solubility. However, the PAH analyte concentrations in the hepatopancreas and muscle did not appear to correlate highly with each other.
Screening pyrene metabolites in the hemolymph of dungeness crabs (Cancer magister) with synchronous fluorescence spectrometry: Method development and application
Authors: Eickhoff Curtis V. , Gobas Frank A. P. C. , Law Francis C. P. 
Published: March 2010

Abstract
The present study examined the metabolic pathways of pyrene in dungeness crabs (Cancer magister) in the laboratory and the potential of using synchronous fluorescence spectrometry (SFS) to determine pyrene metabolite concentrations in the hemolymph of crabs exposed to polycyclic aromatic hydrocarbons (PAHs) in the field. Pyrene was metabolized by crabs mainly to 1-hydroxypyrene and pyrene-1-glucoside. Both pyrene metabolites could be detected by SFS in the hemolymph of crabs. A nondestructive hemolymph collection procedure was developed and used in conjunction with the SFS assay to assess the exposure of crabs to PAHs in Kitimat Arm (British Columbia, Canada). Our results showed that crabs obtained near the source of PAH contamination had the highest level of pyrene-related fluorescence in the hemolymph, whereas concentrations were lower at other sites downstream from the pollution source. In a separate study, the hepatopancreases of crabs were analyzed for parent PAHs by using gas chromatography-mass spectrometry. Pyrene-associated fluorescent responses of the hemolymph were found to correlate positively with the concentration of total PAHs in the hepatopancreas (r = 0.39, p &lt; 0.05).
Immunosuppression in the northern leopard frog (Rana pipiens) induced by pesticide exposure
Authors: Gilbertson Mary-Kate , Haffner G. Douglas , Drouillard Ken G. , Albert Anathea , Dixon Brian 
Published: March 2010

Abstract
An injection study and a field study were used to investigate the hypothesis that environmental xenobiotics have the potential to alter the immune function of northern leopard frogs (Rana pipiens). Three assays, IgM-specific antibody response to keyhole limpet hemocyanin linked to dinitrophenyl (KLH-DNP), zymozan induced chemiluminescence (CL) of whole blood and the delayed-type hypersensitivity (DTH), were used to assay humoral, innate and cell-mediated immune endpoints. Sublethal doses of DDT (923 ng/g wet wt), malathion (990 ng/g wet wt), and dieldrin (50 ng/g wet wt) were used in the injection study. In all pesticide-injected groups, antibody response was dramatically suppressed, DTH reactions were enhanced, and respiratory burst was lower. When the order of administration of pesticides and antigens was reversed, no differences in immune function between the control and dosed groups were apparent, indicating that frogs exposed to pathogens prior to pesticide exposure can still respond. A field study found significant differences in immune function between frog populations in pesticide-exposed and pesticide-free locations. The antibody response and CL were suppressed and the DTH enhanced in frogs from Essex County (ON, Canada). Overall, the results suggest that exposure to these pesticides can cause both stimulatory and suppressive immune changes in adult frogs and is doing so in wild populations.
Plasma cholinesterase levels of mountain plovers (Charadrius montanus) wintering in central California, USA
Authors: Iko William M. , Archuleta Andrew S. , Knopf Fritz L. 
Published: March 2010

Abstract
Declines of over 60% in mountain plover (Charadrius montanus) populations over the past 30 years have made it a species of concern throughout its current range and a proposed species for listing under the U.S. Endangered Species Act. Wintering mountain plovers spend considerable time on freshly plowed agricultural fields where they may potentially be exposed to anticholinesterase pesticides. Because of the population status and wintering ecology of plovers, the objectives of our study were to use nondestructive methods to report baseline plasma cholinesterase (ChE) levels in free-ranging mountain plovers wintering in California, USA, and to assess whether sampled birds showed signs of ChE inhibition related to anticholinesterase chemical exposure. We compared plasma ChE activity for mountain plovers sampled from the Carrizo Plain (an area relatively free of anticholinesterase pesticide use) with similar measures for plovers from the Central Valley (where anticholinesterase pesticides are widely used). Analyses for ChE inhibition indicated that none of the plovers had been recently exposed to these chemicals. However, mean ChE levels of plovers from the Central Valley were significantly higher (32%) than levels reported for plovers from the Carrizo Plain. This result differs from our original assumption of higher exposure risk to mountain plovers in the Central Valley but does suggest that some effect is occurring in the ChE activity of mountain plovers wintering in California.
Bioavailability of desorption-resistant phenanthrene to the oligochaeteIlyodrilus templetoni
Authors: Lu Xiaoxia , Reible Danny D. , Fleeger John W. , Chai Yunzhou 
Published: March 2010

AbstractWe investigated bioavailability, as measured by the biota-sediment accumulation factor (BSAF), of reversibly sorbed and desorption-resistant phenanthrene to the deposit-feeding freshwater tubificid oligochaete Ilyodrilus templetoni. Desorption-resistant, phenanthrene-contaminated sediments were prepared by a sequential batch desorption method by washing with an iso-propanol solution. The BSAFs averaged 1.20 ± 0.32 and 0.59 ± 0.13 for reversibly sorbed phenanthrene and desorption-resistant phenanthrene, respectively, indicating a significantly reduced bioavailability of desorption-resistant phenanthrene. A generalized model assuming a linear relationship between pore-water concentration and normalized bioaccumulation described 91% of the variance for both measured and selected literature data of the BSAF. The reduced bioavailibility of desorption-resistant phenanthrene was thus well described by physical and chemical measures of partitioning between pore water and sediment.
Icon® rice seed treatment toxicity to crayfish (Procambarus clarkii) in experimental rice paddies
Authors: Biever Ronald C. , Hoberg James R. , Jacobson Brian , Dionne Emily , Sulaiman Mohammed , McCahon Peter 
Published: March 2010

Abstract
Outdoor pools (2.3 × 2.3 m) were used to simulate typical rice agricultural practices in Louisiana, USA, to evaluate the toxicity of ICON® (active ingredient [a.i.] fipronil) and its degradates to crayfish (Procambarus clarkii). Six paddies were planted with seed treated with ICON 6.2 FS at an exaggerated application rate of 0.05 kg a.i./ha (recommended rate, 0.042 kg a.i./ha), simulating three rice-planting scenarios. Two reference paddies were planted with untreated seed. Crayfish were exposed to tail water within 24 to 48 h after seeding, simulating standard Louisiana agricultural and water management practices. At 50 d after planting, a separate group of crayfish was caged in situ for 14 d to evaluate toxicity. An additional 50 crayfish were added to two paddies approximately 100 d after rice planting and held for 29 weeks to evaluate bioaccumulation. Residues of fipronil and its degradates in water and soil were similar to residue concentrations measured from rice fields in Louisiana. Tail water from the treated paddies was not toxic to crayfish. The fipronil 96-h median lethal concentration (LC50) for adult crayfish was 180 μg/L, which would provide at least a sixfold safety factor between the maximum fipronil concentration in tail water and the crayfish LC50. In situ exposures of crayfish also were not toxic. Concentrations of fipronil and its degradates after 29 weeks of exposure were less than 5 μg/kg in crayfish tail muscle tissue. These results demonstrate that label instructions adequately protect crayfish in a rice-crayfish cropping scenario when ICON is applied at maximum application rates as a seed treatment.
Bioconcentration and tissue distribution of perfluorinated acids in rainbow trout (Oncorhynchus mykiss)
Authors: Martin Jonathan W. , Mabury Scott A. , Solomon Keith R. , Muir Derek C. G. 
Published: March 2010

AbstractRainbow trout (Oncorhynchus mykiss) were exposed simultaneously to a homologous series of perfluoroalkyl carboxylates and sulfonates in a flow-through system to determine compound-specific tissue distribution and bioconcentration parameters for perfluorinated acids (PFAs). In general, PFAs accumulated to the greatest extent in blood &gt; kidney &gt; liver &gt; gall bladder. Carboxylates and sulfonates with perfluoroalkyl chain lengths shorter than seven and six carbons, respectively, could not be detected in most tissues and were considered to have insignificant bioconcentration factors (BCFs). For detectable PFAs, carcass BCFs increased with increasing length of the perfluoroalkyl chain, ranging from 4.0 to 23,000, based on wet weight concentrations. Carboxylate carcass BCFs increased by a factor of eight for each additional carbon in the perfluoroalkyl chain between 8 and 12 carbons, but this relationship deviated from linearity for the longest PFA tested, possibly because of decreased gill permeability. In general, half-lives (3.9–28 d) and uptake rates (0.053–1,700 L/kg/d) also increased with increasing length of the perfluoroalkyl chain in all tissues. Sulfonates had greater BCFs, half-lives, and rates of uptake than the corresponding carboxylate of equal perfluoroalkyl chain length, indicating that hydrophobicity, as predicted by the critical micelle concentration, is not the only determinant of PFA bioaccumulation potential and that the acid function must be considered.
Effects of pulp and paper mill effluents on reproductive success of largemouth bass
Authors: Sepúlveda Maria S. , Quinn Brian P. , Denslow Nancy D. , Holm Stewart E. , Gross Timothy S. 
Published: March 2010

AbstractThis study evaluated the effects of bleached and unbleached kraft mill effluent on reproductive success of largemouth bass (Micropterus salmoides). Bass were exposed to effluent concentrations (0, 10, 20, 40, or 80%) for 28 and 56 d. Parameters measured included hepatosomatic index (HSI) and gonadosomatic index (GSI) and plasma concentrations of 17β-estradiol (E2), 11-ketotestosterone (11-KT), and vitellogenin (VTG). At the end of the 56-d period, bass were moved to hatchery ponds to evaluate spawning success. Spawning mats with eggs either were brought indoors for evaluation of fecundities, hatchabilities, and egg and fry size (measured at age 3 d), or were left in ponds and fry number and size recorded (average age of 14 d). Effluent exposure was verified by measuring resin acids (isopimaric, abietic, and dehydroabietic acids) in bile. Compared to controls, exposed bass had greater concentrations of resin acids in bile. In general, exposed females had lower concentrations of E2 and VTG (≥20% effluent), whereas males had lower concentrations of 11-KT (≥20% effluent) and increased E2 (≥20% effluent). The HSI values increased in females (≥10% effluent), and GSI values decreased in both sexes (≥40% effluent). Fecundity, egg size, and hatchability did not differ across treatments, but an increase in the frequency of fry abnormalities and a decrease in fry weights was observed at effluent exposures of 40% and higher. However, results from the pond study, revealed a significant reduction in fry growth and survival (≥10%). This decline may have been caused by an increased frequency of deformities, in conjunction with alterations of growth. These changes could have resulted from alterations in egg quality because of failure of parental reproductive systems, from acute embryo toxicity after translocation of contaminants from the mother to the developing embryo, or from both.
Pyrene biotransformation products as biomarkers of polycyclic aromatic hydrocarbon exposure in terrestrial isopoda: Concentration-response relationship, and field study in a contaminated forest
Authors: Stroomberg Gerard J. , Ariese Freek , van Gestel Cornelis A. M. , van Hattum Bert , Velthorst Nel H. , van Straalen Nico M. 
Published: March 2010

AbstractIn this study, biotransformation products of pyrene were measured in the hepatopancreas of terrestrial isopods as biomarkers of polycyclic aromatic hydrocarbon (PAH) exposure. These products—pyrene-1-glucoside, pyrene-1-sulfate, an unknown pyrene conjugate, and 1-hydroxypyrene—were quantitated using high-performance liquid chromatography (HPLC) with fluorescence detection. In a controlled exposure experiment, a linear relationship was established between pyrene exposure and pyrene metabolite concentrations in the hepatopancreas of Porcellio scaber Latr. To this end, isopods of the species P. scaber were exposed to a range of pyrene concentrations spiked to their food. A linear response was found for all pyrene conjugates in the range 0.67 to 67 μg/g of pyrene (dry wt). Hepatopancreatic pyrene metabolite concentrations were also measured in isopods (P. scaber and Oniscus asellus L.) from PAH-contaminated field sites. The sites and the inhabiting isopods were located in a gradient of atmospheric PAH deposition caused by a nearby blast furnace plant. The highest levels of conjugated 1-hydroxypyrene in the hepatopancreas were 3.8 pmol/g fresh weight (pyrene-1-glucoside) and 2.8 pmol/g fresh weight (pyrene-1-sulfate) (expressed on whole-body basis). The levels of the pyrene metabolites correlate with reported pyrene concentrations in spite of these sites. As pyrene is one of the most predominant PAHs, analysis of its metabolites provides a good tool for environmental risk assessment of ecosystems with regard to PAH exposure, bioavailability, and biotransformation.
Specific responses of bacterial cells to dioxins
Authors: Min Jiho , Pham Chi Hoa , Gu Man Bock 
Published: March 2010

Abstract
Five different recombinant bioluminescent strains of Escherichia coli that contain the recA (responsive to DNA damage related stress), fabA (membrane damage), katG (oxidative damage), grpE (protein damage), and lac (constitutive expression, general toxicity) promoters fused to the bacterial lux operon from either Vibrio fischeri or Photorhabdus luminescens were used to describe the different mechanisms of toxicity that several dibenzo-p-dioxins and dibenzofurans have on bacteria, as well as to determine whether bacteria can sensitively detect the presence of these compounds. 2,3,7,8-Tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) was found to cause only DNA-related damage to bacterial cells. However, the four stress-responsive strains showed positive responses after addition of l,2,3,4-tetrachlorodibenzo-p-dioxin (1,2,3,4-TCDD), whereas 2,3,7,8-tetrachlorodibenzo-p-furan (2,3,7,8-TCDF) caused only DNA, oxidative, and protein damage. However, 2,8-dichlorodibenzo-p-dioxin (2,8-DCDD) was not found to induce any stresses tested for in this study, that is, DNA, membrane, oxidative, and protein damage, indicating that each congener might differentially interact with the cell, stimulating differential stress responses within them. By using the constitutive strain, we found that the level of cellular toxicity experienced due to the addition of these four dioxins decreased in the order of 2,3,7,8-TCDD (the most toxic), 1,2,3,4-TCDD, 2,8-DCDD, and 2,3,7,8-TCDF. The 20% effective concentration (EC20), defined in this study the concentration of chemical that causes a 20% decrease in the bioluminescence 60 min after induction, was only 0.1 μg/L for 2,3,7,8-TCDD, a value that is lower than that of the other congeners and demonstrates that 2,3,7,8-TCDD was the most toxic compound tested in this study.
Toxicity of lead in aqueous medium to Desulfovibrio desulfuricans G20
Authors: Sani Rajesh K. , Peyton Brent M. , Jandhyala Malathi 
Published: March 2010

Abstract
The toxicity of Pb(II) to sulfate-reducing bacteria (SRB) was studied using Desulfovibrio desulfuricans G20 in a medium specifically designed to assess metal toxicity. The effects of Pb(II) toxicity were observed in terms of longer lag times, lower specific growth rates, and in some cases no measurable growth. With an increase in medium pH from 6 to 8, Pb(II) toxicity decreased. At all pH values, in the presence of Pb(II) concentrations ranging from 3 to 15 μM, specific growth rates decreased and lag times increased. The minimum inhibiting concentration (MIC) of Pb(II) causing a complete inhibition in growth at pH 6 was 10 μM, as compared to 15 μM at pH 7.2 and 8. These MIC values are 40 times lower than previously reported for SRB. Results also show that with increases in initial cell protein concentration (inoculum size), soluble Pb(II) removal rates increased and the degree to which Pb(II) caused increased lag times was reduced. In the presence of Pb(II), in all cases in which D. desulfuricans grew (even after a 312-h lag time), the final cell protein concentration was equivalent to that of the Pb-free control. Live/dead staining, based on membrane integrity, indicated that while Pb(II) inhibited growth, Pb(II) did not cause a loss of D. desulfuricans membrane integrity.
Abiotic transformation of chlorpyrifos to chlorpyrifos oxon in chlorinated water
Authors: Wu Jigang , Laird David A. 
Published: March 2010

Abstract
In vivo transformation of chlorpyrifos to chlorpyrifos oxon is believed to be a prerequisite for this insecticide to display acute toxicity to organisms. We discovered that active chlorine dispersed in water causes the rapid abiotic transformation of chlorpyrifos to chlorpyrifos oxon. The proposed mechanism for the transformation is an electrophilic attack by hypochlorous acid (HOCl) on the thion (P=S) double bond of chlorpyrifos followed by desulfuration of chlorpyrifos to its oxon analog. The pH of a Cl-aqueous solution controls the speciation of HOCl and hypochlorite (OCl−) in water and thereby influences the transformation process. Chlorpyrifos oxon is a potent anticholinesterase that is about 1,000 times more toxic than chlorpyrifos. Because chlorination is commonly used for treatment of domestic water supplies, the findings raise a new concern about the safety of domestic use of chlorpyrifos products.
Quantitative structure-biodegradation relationship study for biodegradation rates of substituted benzenes by river bacteria
Authors: Lu Guang H. , Wang Chao , Bao Guo Z. 
Published: March 2010

Abstract
The biodegradation rate constant (K) of 21 substituted phenols, anilines, and benzoic acids was determined by using bacteria from the Songhua River (Jilin Province, China) as an inoculum. All of the compounds studied are readily biodegradable chemicals, as shown by their high K values. The quantitative structure-biodegradation relationship results showed that the biodegradation rate of the studied compounds is related mainly to the heat of formation (Hf) and the negative logarithm of the ionization constant (pKa), whereas no simple relationship exists with the n-octanol-water partition coefficients. The equation K = −1.127 × 10−3Hf -0.0388pKa + 0.859 was found to fit well (r2(adj) = 0.805), and the correlation coefficient between the predicted and the experimental K values was up to 0.908.