bluuebunny/crossref_metadata_2025_split huggingface dataset:
Genetic variation in red raspberries (Rubus idaeus L.; rosaceae) from sites differing in organic pollutants compared with synthetic tandem repeat DNA probes
Authors: Keane Brian , Smith M Kate , Rogstad Steven H 
Published: March 2010

Abstract
Two synthetic tandem repetitive DNA probes were used to compare genetic variation at variable-number-tandem-repeat (VNTR) loci among Rubus idaeus L. var. strigosus (Michx.) Maxim. (Rosaceae) individuals sampled at eight sites contaminated by pollutants (N = 39) and eight adjacent uncontaminated sites (N = 38; distances separating sites ranged from 5 to 350 m). For the 77 plants analyzed, the mean number of bands scored per individual was 16.5 (SD = 3.5). Mean genetic similarity (0.51) and heterozygosity (0.62) across all plants from contaminated sites did not differ significantly from that among all plants from uncontaminated sites (mean similarity = 0.52; mean heterozygosity = 0.63). Nor did similarity and heterozygosity differ between contaminated and uncontaminated sites when estimates of these values within each of the 16 sites were compared. Estimates ofFst (0.01-0.04) indicated little genetic differentiation between plants from contaminated and uncontaminated sites. However, relative to plants from uncontaminated sites, plants from contaminated sites possessed significantly fewer private alleles (1 vs 18; p &lt; 0.001) and alleles per individual (mean = 15.2 vs 17.9; p = 0.0002). Considering the 16 sites individually, uncontaminated sites possess significantly more population bands (p = 0.015), private alleles (p = 0.01), and alleles per individual (p = 0.027). These differences were distributed across sites rather than resulting from large, idiosyncratic differences attributable to one or a few outlier sites. The findings of this study suggest that a loss of genetic variation among R. idaeus individuals growing in impacted areas has occurred at all eight sites, and that VNTR markers may be useful biological indicators of plant populations under stress from human perturbations. In addition, extensive clonal spread of this species, previously documented for other species of Rubus, was not detected.
Impact of azadirachtin on Glomus intraradices and vesicular-arbuscular mycorrhiza in root inducing transferred dna transformed roots of Daucus carota
Authors: Wan Michael T , Rahe James E 
Published: March 2010

Abstract
The impact of azadirachtin, neem extracts, and their products, Eneem 3G and Neemix® 4.5E, on the symbiotic vesicular-arbuscular mycorrhizal fungus Glomus intraradices was assessed by short-term subacute toxicity tests using root inducing transferred DNA (Ri T-DNA) transformed roots of Daucus carota as the host in the minimal medium system. The concentration causing 50% inhibition of growth and development was determined, and effects of these test materials on carrot roots and colonization by G. intraradices were also evaluated. The inhibitory effect of azadirachtin and neem compounds was compared with that of several reference pesticides (benomyl, chlorothalonil, copper sulfate, dimethoate, glyphosate, and its metabolite aminomethyl-phosphonic acid). Azadirachtin, neem extracts, Eneem 3G, and Neemix 4.5E, including their carriers and solvents, have low short-term toxicity to G. intraradices when compared with reference pesticides. As well, neither D. carota nor the vesicular-arbuscular mycorrhizal colonization was affected by these compounds. The potential ecotoxicological impact of azadirachtin, a new botanical insecticide, on the terrestrial environment is evaluated and discussed.
Mercury and plants in contaminated soils: 2. Environmental and physiological factors governing mercury flux to the atmosphere
Authors: Leonard Todd L , Taylor George E , Gustin Mae S , Fernandez George C.J 
Published: March 2010

Abstract
The objective of this study was to evaluate the role of physiological and environmental factors in governing the flux of elemental mercury from plants to the atmosphere. Five species (Lepidium latifolium, Artemisia douglasiana, Caulanthus sp., Fragaria vesca, and Eucalyptus globulus) with different ecological and physiological attributes and growing in soils with high levels of mercury contamination (34 to 54 μg/g) were examined. Studies were conducted in a whole-plant, gas-exchange chamber providing precise control of environmental conditions, and mercury flux was estimated using the mass balance approach. Mercury flux increased linearly as a function of temperature within the range of 20 to 40°C, and the mean temperature coefficient (Q10) was 2.04. The temperature dependence of mercury flux was attributed to changes in the contaminant's vapor pressure in the leaf interior. Mercury flux from foliage increased linearly as a function of irradiance within the range of 500 to 1,500 μmol m/s, and the light enhancement of mercury flux (flux ratio at 1,500:500 μmol m/s) was within a factor of 2.0 to 2.5 for all species. Even though the leaf-to-atmosphere diffusive path for mercury vapor from foliage is similar to that of water vapor, stomatal conductance played a secondary role in governing mercury flux. In a quantitative comparison with other studies in both laboratory and field settings, a strong linear relationship is evident between mercury vapor flux and the natural logarithm of soil mercury concentration, and this relationship may have predictive value in developing regional- and continental-scale mercury budgets. The most critical factors governing mercury flux from plants are mercury concentration in the soil, leaf area index, temperature, and irradiance.
Linking teratogenesis, growth, and DNA photodamage to artificial ultraviolet b radiation in Xenopus laevis larvae
Authors: Bruggeman Douglas J , Bantle John A , Goad Carla 
Published: March 2010

Abstract
The frog embryo teratogenesis assay—Xenopus (FETAX) was used to illustrate sublethal endpoints indicative of ultraviolet B (UV-B) radiation exposure in Xenopus laevis larvae. Xenopus laevis embryos were covered with plastic cutoff filters to manipulate UV dose, and irradiated under a light carriage consisting of two UV-B and three UV-A bulbs. At the end of day 2, 20% of the tadpoles from all treatments were removed, and DNA was extracted. Frequency of pyrimidine dimers was estimated by quantifying single-strand breaks after incubating DNA with an endonuclease specific for cyclobutane pyrimidine dimers. Remaining tadpoles were sacrificed on day 5, and mortality, malformations, and growth data were recorded. Teratogenesis and growth inhibition were positively correlated with increasing UV-B dose in all tests. Photodamage to DNA in experiment 1 increased with higher UV-B doses. Teratogenesis positively correlated with the frequency of pyrimidine dimers. In experiment 2, significant variation with DNA photodamage in egg clutches was observed and no treatment effect was found. Usage of these sublethal endpoints in the field or laboratory would be helpful in discerning adaptational responses of developing amphibians to UV-B radiation, and interactive effects between UV and photosensitive chemicals.
Toxicity of chlorobenzenes to alux-marked terrestrial bacterium,Pseudomonas fluorescens
Authors: Boyd Elaine M , Meharg Andrew A , Wright Julian , Killham Ken 
Published: March 2010

AbstractInsertion of lux genes, encoding for bioluminescence in naturally bioluminescent marine bacteria, into the genome of Pseudomonas fluorescens resulted in a bioluminescent strain of this terrestrial bacterium. The lux-marked bacterium was used to toxicity test the chlorobenzene series. By correlating chlorobenzenes 50% effective concentration (EC50) values against physiochemical parameters, the physiochemical properties of chlorobenzenes that elicit toxic responses were investigated. The results showed that the more chlorinated the compounds, the more toxic they were to lux-marked P. fluorescens. Furthermore, it was shown that the more symmetrical the compound, the greater its toxicity to P. fluorescens. In general, the toxicity of a chlorobenzene was inversely proportional to its solubility (S) and directly proportional to its lipophilicity (Kow). By correlating lux-marked P. fluorescens EC50 values, determined for chlorobenzenes, with toxicity values determined using Pimephales promelas (fathead minnow), Cyclotella meneghiniana (diatom), and Vibrio fischeri (marine bacterium), it was apparent that lux-marked P. fluorescens correlated well with freshwater species such as the diatoms and fathead minnow but not with the bioluminescent marine bacterium V. fischeri. The implications of these findings are that a terrestrial bacterium such as P. fluorescens should be used for toxicity testing of soils and freshwaters rather than the marine bacterium V. fischeri.
Physicochemical characterization of residual mineral oil contaminants in bioremediated soil
Authors: Angehrn Daniel , Gälli René , Zeyer Josef 
Published: March 2010

Abstract
After bioremediation of mineral oil—contaminated soils, residual contaminants can remain in the soils. In this article, an analytical concept to determine the physicochemical properties of residual contaminants that can be used to assess the environmental fate and potential environmental hazards of these chemicals is presented and discussed. This concept can serve as a tool to characterize unknown compounds within a complex mixture on the basis of basic analytical data. The volatility of the residual contaminants was determined by headspace analyses, but no volatile organic compounds (with a boiling point of &lt;280°C) were present. Soxhlet extraction using tetrachloromethane was found to be the most efficient method to obtain the total solvent extractable material (TSEM). Information about the polarity of the contaminants in TSEM was obtained by flash chromatography. It was found that the majority of the residual contaminants are present in the fractions containing nonpolar components, such as branched or cyclic aliphatics and alkylated aromatics. A minor fraction consisted of compounds with polar functional groups, such as long-chain alkanals, alkanols, and alkanoic acids. Information about the octanol/water partition coefficient (Kow) of the contaminants within the TSEM was obtained with use of a combination of two independent chromatographic separation steps, reverse-phase high-performance liquid chromatography, followed by high-resolution gas chromatography. Depending on the compound classes, Kow values varied accordingly but were above 106. Considering these Kow values, the mobility of the residual contaminants in bioremediated soils is expected to be very low.
Evidence for differential effects of 2,4,6-trinitrotoluene and other munitions compounds on specific subpopulations of soil microbial communities
Authors: Fuller Mark E , Manning John F 
Published: March 2010

AbstractThe effects of 2,4,6-trinitrotoluene (TNT) and other munitions compounds on indigenous microbial communities in several soils were examined. Culturable heterotrophs, concentrations of phospholipid fatty acid (PLFA), and basal respiration rates exhibited slight negative correlations with high TNT and 1,3,5-trinitrobenzene (TNB) levels. Heat-shock-resistant culturable heterotrophs, percentage of gram-positive soil isolates, mole percent of branched PLFA, and 10Me18:0 (tuberculostearic acid) were observed to be significantly lower in highly contaminated soils. Total soil nitrogen levels were positively correlated with high TNT and TNB concentrations, whereas total soil carbon exhibited no significant correlation with either compound. Multivariate analysis of PLFA data resulted in distinct separation of soils with respect to their degree of contamination, with specific signature PLFAs for gram-positive bacteria, fungi, and protozoa being negatively associated with high contaminant levels. Apparent concentrations of TNT resulting in 50% reductions in indicators of gram-positive populations were much higher than values from pure culture experiments, possibly as a result of low bioavailability due to sorption onto clay and soil organic matter. Few effects of other munitions compounds were observed. Closer examination of a highly contaminated soil revealed that the number of culturable heterotrophs growing on 0.3% molasses plates decreased by 50% when 67 μg TNT/ml was added to the medium; a 99% decrease was observed for soil contaminated with less than 20 μg TNT/g. Highly contaminated soil harbored a greater number of organisms that were able to grow on plates amended with greater than 10 μg TNT/ml. Gram-positive isolates from both soils demonstrated marked growth inhibition when greater than 8-16 μg TNT/ml was present in the culture medium. These results indicate that chronic exposure to munitions compounds can dramatically alter soil microbial communities.
Rapid method for assessing pollution-induced community tolerance in contaminated soil
Authors: Rutgers Michiel , Verlaat Ilse M van't , Wind Bea , Posthuma Leo , Breure Anton M 
Published: March 2010

Abstract
Using the pollution-induced community tolerance (PICT) concept, this article presents a rapid method for detecting toxic effects of contaminated soil on soil microbial communities and for elucidating the causal relationship between exposure history and toxic effects in exposed microbial communities. The method is based on the use of multiwell plates (Biolog®) for producing concentration versus effect relationships for (maximally) 95 different microbial metabolic activities. For this, artificial exposure in the multiwell plate is established to the contaminant supposedly causing toxic effects in the field. The method was tested in a gradient of zinc-contaminated field plots by studying community tolerance to zinc. For most substrates the metabolic activities showed an increased community tolerance for zinc with increased zinc concentration in the field. Consequently, PICT has evolved after 2.5 years of zinc exposure under field conditions. The perspectives for future use of the PICT concept in combination with the multiwell technique for demonstrating ecotoxicological effects at contaminated sites is exemplified by the comparison of Dutch soil quality criteria for zinc with the collected data. This comparison showed that the evolution of microbial-PICT for zinc has occurred at environmental concentrations near the Dutch intervention value, a quality criterion linked to remediation urgency.
Monitoring aquatic environments receiving industrial effluents using small fish species 1: Response of spoonhead sculpin (Cottus ricei) downstream of a bleached-kraft pulp mill
Authors: Gibbons Wade N , Munkittrick Kelly R , Taylor William D 
Published: March 2010

AbstractLarger fish species may not always be suitable for monitoring the response to industrial effluents because they are mobile and capable of extensive movement beyond effluent exposure areas. Spoonhead sculpin (Cottus ricei) was collected upstream and downstream of a large bleached-kraft pulp mill on the Athabasca River, Alberta, Canada, during fall and spring periods to determine whether small, sedentary fish species demonstrate responses reflecting local exposure conditions. During the fall sampling period, exposed fish were older and larger than upstream fish and showed increases in condition, gonad size, egg weight, liver weight, and hepatic mixed function oxygenase activity (7-ethoxyresorufin O-deethylase [EROD]). Sculpin collected from the opposite river bank, where exposure was reduced, showed condition factors, gonad size, egg weight, liver weight, and EROD activity that were not significantly different from reference sites or intermediate between reference and downstream values. In the spring after a prolonged overwinter exposure to higher effluent concentrations, exposed fish were larger, showed increased size-at-age, condition, liver weight, ovary size, and EROD activity. Far-field collections showed that most responses persisted downstream for at least 48 km. The general response of exposed spoonhead sculpin was consistent with a nutrient enrichment effect described in studies investigating water quality, algal growth, and benthos communities at this site but also may be related to reduced competition associated with the loss of older fish observed in the spring. The use of small species for sentinel monitoring provided a viable alternative to use of larger, more mobile species.
Monitoring aquatic environments receiving industrial effluents using small fish species 2: Comparison between responses of trout-perch (Percopsis omiscomaycus) and white sucker (Catostomus commersoni) downstream of a pulp mill
Authors: Gibbons Wade N , Munkittrick Kelly R , McMaster Mark E , Taylor William D 
Published: March 2010

Abstract
To further evaluate the suitability of small fish species for sentinel monitoring, a comparison was made between the responses of trout-perch (Percopsis omiscomaycus) and the larger white sucker (Catostomus commersoni) under similar conditions of pulp mill effluent exposure and mobility. Fish were collected upstream and downstream of a thermomechanical pulp mill on the Kapuskasing River, Ontario, Canada, where the presence of a hydro dam restricts the movement of fish between reference and exposure areas. Trout-perch collected downstream of the mill were shorter, lighter, and younger than upstream fish, whereas exposed white sucker were longer, heavier, and, for male sucker, older than reference fish. Only male trout-perch showed induced hepatic mixed function oxygenase activity (7-ethoxyresorufin-O-deethylase). Both forskolin-stimulated in vitro production of 17 β-estradiol in trout-perch and plasma concentrations of 17 β-estradiol in sucker were significantly depressed in exposed fish. The inconsistency in responses between species made it difficult to determine how the opposing responses were related and which species was most sensitive to instream conditions. Despite the discrepancies, use of an interpretation framework indicated that both species identified similar potential problems (e.g., size-selective mortality and recruitment problems), suggesting that either species could be used as a sentinel species at this site.
Validation of hsp70 stress gene expression as a marker of metal effects in Deroceras reticulatum (pulmonata): Correlation with demographic parameters
Authors: Köhler Heinz-R , Belitz Beatrix , Eckwert Helga , Adam Ralf , Rahman Basim , Trontelj Peter 
Published: March 2010

Abstract
The presence of a stress gene comprising a motif homologous to the hsp70 consensus sequence was proven for the grey garden slug, Deroceras reticulatum (Müller). The induction of stress gene transcription (including mRNA stability) and the accumulation of the corresponding stress protein, Hsp70, was quantified in slugs exposed to cadmium- or zinc-enriched food for 2 to 3 weeks. To validate the suitability of these two aspects of the cellular stress reponse to act as early-warning markers for metal effects on life-history parameters, fecundity, offspring number, longevity, and mortality of slugs were recorded in life-cycle experiments. Quantitative reverse transcription-polymerase chain reaction and a standardized immunoblotting technique revealed higher sensitivity of changes in hsp70 transcription than stress protein accumulation in response to both metals. The elevation of the hsp70-mRNA level caused by short-term (14 d) metal exposure coincided with both diminished fecundity and reduced offspring production due to chronic metal exposure in terms of threshold concentrations for cadmium (˜0.2 mg/kg) and zinc (˜200 mg/kg) effects. As well, accumulation of Hsp70 after 3 weeks of exposure can be considered an early-warning signal for increased mortality when cadmium (threshold concentration ˜0.3-2 mg/kg) or zinc exposure (threshold concentration ˜0.4-2 g/kg) is throughout the entire lifetime of the slugs.
Transformaton of 2,4,6-trinitrotoluene by the aquatic plantMyriophyllum spicatum
Authors: Pavlostathis Spyros G , Comstock Kelly K , Jacobson Myrna E , Saunders F Michael 
Published: March 2010

AbstractThe ability of the aquatic plant Eurasian Watermilfoil (Myriophyllum spicatum) to transform 2,4,6-trinitrotoluene (TNT) was investigated in a series of batch assays. The TNT was added to plant cultures in single and multiple consecutive additions, at various initial concentrations, to determine its transformation kinetics, identify products formed, evaluate phytotoxic effects, and to determine the effect of light deprivation on the TNT transformation process. Rapid disappearance of TNT from the plant culture media was observed. The TNT disappearance rate was a function of both plant and TNT concentration (i.e., followed mixed, second-order kinetics). The TNT transformation occurred only in the presence of plants and was inhibited by the addition of sodium azide. Phytotoxicity leading to plant chlorosis was observed in batch plant cultures with an initial TNT concentration above 5.9 μM. Reductive transformation of TNT to aminodinitrotoluenes and lower levels of hydroxylaminodinitrotoluene and diaminonitrotoluenes detected in the plant culture media accounted for less than 10 to 20% of the total TNT mass added. Extraction of plant material at the end of batch incubations when all TNT was depleted from the media yielded low levels of TNT and aminodinitrotoluenes and accounted for only 3.4% of the initially added TNT mass. Light deprivation decreased both the rate and extent of the reductive transformation of TNT.
Growing food crops on sludge-amended soils: Problems with the U.S. Environmental Protection Agency method of estimating toxic metal transfer
Authors: McBride Murray B 
Published: March 2010

Abstract
The use of sewage sludges as farm fertilizers, encouraged in recent years by changes in U.S. Environmental Protection Agency (U.S. EPA) policy, has raised concerns among some scientists regarding food safety and long-term soil productivity. The U.S. EPA risk assessment for entry into the human diet of three of the most toxic metals, cadmium (Cd), mercury (Hg), and lead (Pb), utilized uptake coefficients (UCs) to calculate the amount of each metal that could enter food crops from the soil. Each UC was calculated as the increment of metal concentration in the edible part of the crop per unit increase of metal loading to the soil. However, the final UC estimates employed in the risk assessment are biased toward low values by a number of factors. These include the use of geometric means to obtain single-point averages of UCs for each crop group evaluated, rather than using arithmetic means or probabilistic methods, a systematic analytical or contamination error apparent in the reported metal concentrations of the control crops, and the fact that most of the UC values were derived for soils with pH 6 or higher. For more than 50% of all the soil and cropping conditions represented in the risk assessment, the geometrically averaged Cd UC values used by the U.S. EPA underestimated the actual risk posed by uptake into crops. The UC values for Pb and Hg are uncertain because of analytical or contamination errors, and because of the few data available for a number of crops. These uncertainties and biases in the risk assessment would advise a more cautious approach to agricultural and home garden use of sewage sludge than is permitted by the U.S. EPA 503 rule.