Charles S.,CNRS Biometry and Evolutionary Biology Laboratory |
Ducrot V.,French National Institute for Agricultural Research |
Ducrot V.,Bayer AG |
Azam D.,French National Institute for Agricultural Research |
And 20 more authors.
Regulatory Toxicology and Pharmacology | Year: 2016
This paper presents the results from two ring-tests addressing the feasibility, robustness and reproducibility of a reproduction toxicity test with the freshwater gastropod Lymnaea stagnalis (RENILYS strain). Sixteen laboratories (from inexperienced to expert laboratories in mollusc testing) from nine countries participated in these ring-tests. Survival and reproduction were evaluated in L. stagnalis exposed to cadmium, tributyltin, prochloraz and trenbolone according to an OECD draft Test Guideline. In total, 49 datasets were analysed to assess the practicability of the proposed experimental protocol, and to estimate the between-laboratory reproducibility of toxicity endpoint values. The statistical analysis of count data (number of clutches or eggs per individual-day) leading to ECx estimation was specifically developed and automated through a free web-interface. Based on a complementary statistical analysis, the optimal test duration was established and the most sensitive and cost-effective reproduction toxicity endpoint was identified, to be used as the core endpoint. This validation process and the resulting optimized protocol were used to consolidate the OECD Test Guideline for the evaluation of reproductive effects of chemicals in L. stagnalis. © 2016 Elsevier Inc.
Horn P.,University of Rostock |
Schlichting A.,University of Rostock |
Baum C.,University of Rostock |
Hammesfahr U.,University of Trier |
And 4 more authors.
Journal of Biotechnology | Year: 2016
We introduce an easy, fast and effective method to analyze the influence of genetically modified (GM) plants on soil and model organisms in the laboratory to substitute laborious and time consuming field trials. For the studies described here we focused on two GM plants of the so-called 3rd generation: GM plants producing pharmaceuticals (PMP) and plant made industrials (PMI). Cyanophycin synthetase (cphA) was chosen as model for PMI and Choleratoxin B (CTB) as model for PMP. The model genes are expressed in transgenic roots of composite Vicia hirsuta plants grown in petri dishes for semi-sterile growth or small containers filled with non-sterile soil. No significant influence of the model gene expression on root induction, growth, biomass, interaction with symbionts such as rhizobia (number, size and functionality of nodules, selection of nodulating strains) or arbuscular mycorrhizal fungi could be detected. In vitro, but not in situ under field conditions, structural diversity of the bulk soil microbial community between transgenic and non-transgenic cultivars was determined by PLFA pattern-derived ratios of bacteria: fungi and of gram+: gram- bacteria. Significant differences in PLFA ratios were associated with dissimilarities in the quantity and molecular composition of rhizodeposits as revealed by Py-FIMS analyses.Contrary to field trials, where small effects based on the transgene expression might be hidden by the immense influence of various environmental factors, our in vitro system can detect even minor effects and correlates them to transgene expression with less space, time and labour. © 2016 Elsevier B.V.
Ruppert K.,Goethe University Frankfurt |
Geiss C.,Goethe University Frankfurt |
Askem C.,CEFAS Lowestoft Laboratory Pakefield Road |
Benstead R.,FERA |
And 24 more authors.
Chemosphere | Year: 2017
Mollusks are known to be uniquely sensitive to a number of reproductive toxicants including some vertebrate endocrine disrupting chemicals. However, they have widely been ignored in environmental risk assessment procedures for chemicals. This study describes the validation of the Potamopyrgus antipodarum reproduction test within the OECD Conceptual Framework for Endocrine Disrupters Testing and Assessment. The number of embryos in the brood pouch and adult mortality serve as main endpoints. The experiments are conducted as static systems in beakers filled with artificial medium, which is aerated trough glass pipettes. The test chemical is dispersed into the medium, and adult snails are subsequently introduced into the beakers. After 28 days the reproductive success is determined by opening the brood pouch and embryo counting. This study presents the results of two validation studies of the reproduction test with eleven laboratories and the chemicals tributyltin (TBT) with nominal concentrations ranging from 10 to 1000 ng TBT-Sn/L and cadmium with concentrations from 1.56 to 25 μg/L. The test design could be implemented by all laboratories resulting in comparable effect concentrations for the endpoint number of embryos in the brood pouch. After TBT exposure mean EC10, EC50, NOEC and LOEC were 35.6, 127, 39.2 and 75.7 ng Sn/L, respectively. Mean effect concentrations in cadmium exposed snails were, respectively, 6.53, 14.2, 6.45 and 12.6 μg/L. The effect concentrations are in good accordance with already published data. Both validation studies show that the reproduction test with P. antipodarum is a well-suited tool to assess reproductive effects of chemicals. © 2017 Elsevier Ltd
Rombke J.,ECT Oekotoxikologie GmbH |
Barrett K.,Huntingdon Life science |
Blanckenhorn W.U.,University of Zürich |
Hargreaves T.,Charles River Associates |
And 7 more authors.
Science of the Total Environment | Year: 2010
A standardized bioassay using the face fly, Musca autumnalis L. (Diptera: Muscidae), was developed to test the lethal and sublethal toxicity of parasiticide residues in livestock dung. The repeatability of this test was assessed for the parasiticide ivermectin in seven tests performed in four laboratories in Germany and France. Additional results of limit tests were provided by two laboratories from the UK. Test results had an acceptable range of heterogeneity. The calculated effect concentration at which 50% emergence was observed (EC50) averaged 4.65 ± 2.17 (Standard Deviation (SD) μg ivermectin/kg fresh dung (range: 1.20-7.7)). Effects on emergence were, with one exception, not observed below the No Observed Effect Concentration (NOEC) ranging between 1.11 and 3.33μg ivermectin/kg. No effect on development time was observed. We conclude that the face fly is suitably sensitive, and the methods sufficiently repeatable, to support use of this standardized bioassay by the international community in the registration of new veterinary pharmaceuticals. Following these considerations, this species was accepted as a possible test organism in a recently published OECD Guideline (No. 228). © 2010 Elsevier B.V.
PubMed | The-Edge, Ibacon GmbH, WIL Research, Bayer AG and 14 more.
Type: | Journal: Regulatory toxicology and pharmacology : RTP | Year: 2016
This paper presents the results from two ring-tests addressing the feasibility, robustness and reproducibility of a reproduction toxicity test with the freshwater gastropod Lymnaea stagnalis (RENILYS strain). Sixteen laboratories (from inexperienced to expert laboratories in mollusc testing) from nine countries participated in these ring-tests. Survival and reproduction were evaluated in L.stagnalis exposed to cadmium, tributyltin, prochloraz and trenbolone according to an OECD draft Test Guideline. In total, 49 datasets were analysed to assess the practicability of the proposed experimental protocol, and to estimate the between-laboratory reproducibility of toxicity endpoint values. The statistical analysis of count data (number of clutches or eggs per individual-day) leading to ECx estimation was specifically developed and automated through a free web-interface. Based on a complementary statistical analysis, the optimal test duration was established and the most sensitive and cost-effective reproduction toxicity endpoint was identified, to be used as the core endpoint. This validation process and the resulting optimized protocol were used to consolidate the OECD Test Guideline for the evaluation of reproductive effects of chemicals in L.stagnalis.
Mead-Briggs M.A.,Mambo Tox Ltd |
Moll M.,Ibacon GmbH |
Grimm C.,Syngenta |
Schuld M.,GAB Biotechnologie GmbH |
And 2 more authors.
BioControl | Year: 2010
This guideline describes a standardised form of extended laboratory test for evaluating the effects of plant protection products on the parasitic wasp, Aphidius rhopalosiphi (De Stefani-Perez) (Hymenoptera, Braconidae), both in terms of acute treatment effects (i.e. mortality over a 48 h exposure period) and sub-lethal treatment effects (i.e. changes in the reproductive capacity of surviving wasps). The test method involves the treatment of a 3-dimensional test substrate (barley seedlings), over which the test insects (laboratory-bred female wasps, less than 48-h-old) are confined for 48 h. Surviving wasps are then individually confined over untreated aphid-infested plants for 24 h and the numbers of parasitised aphids in which wasp pupae subsequently develop are recorded. Acute mortality after 48 h and the mean number of 'mummies' (the pupal stage of the wasps) produced per female are used as assessment endpoints for the test. © 2009 International Organization for Biological Control (IOBC).
Hoss S.,Ecossa |
Hoss S.,Institute For Biodiversitat Netzwerk Ibn |
Reiff N.,Ecossa |
Nguyen H.T.,Dienstleistungszentrum Landlicher Raum Rheinpfalz |
And 5 more authors.
Science of the Total Environment | Year: 2014
Small-scale laboratory microcosms (30g soil in 50ml tubes) were evaluated for their suitability to assess the impact of chemicals on in situ soil nematode communities. For this purpose, appropriate conditions in the microcosms were explored to ensure stable conditions and a homogenous distribution of the nematodes. Then, the microcosms were used to assess the toxicity of insecticidal crystal proteins (Cry1A.105, Cry2Ab2, Cry3Bb1) present in genetically modified maize (MON89034×MON88017) on in situ nematode communities. Highly abundant and genus rich nematode communities could be maintained over a period of 12weeks. Due to a low variance between the replicates of the treatments, low detection limits could be achieved. Using meaningful stress indices, such as the maturity indices, the microcosm study revealed dose-dependent effects of the insecticidal Cry proteins that could be verified as toxic effects by comparing with effects of two positive controls (Cu, nematicidal Cry5B). Moreover, toxic effects could be differentiated from organic enrichment effects that were induced by the addition of plant material. With a NOECCommunity of 0.1mgkg-1 dry wt, the nematode communities reacted considerably more sensitive to the Cry proteins than a single-species nematode toxicity test (NOEC: 29mgl-1). The small-scale microcosm set-up turned out to be a suitable, low-budget tool for assessing the toxicity of chemicals on soil nematodes on community level, representing a link between single-species toxicity tests and large scale outdoor mesocosms. © 2013.
Jeong D.-H.,University of Delaware |
Schmidt S.A.,University of Delaware |
Rymarquis L.A.,University of Delaware |
Rymarquis L.A.,Monsanto Corporation |
And 15 more authors.
Genome Biology | Year: 2013
Background: The wild grass Brachypodium distachyon has emerged as a model system for temperate grasses and biofuel plants. However, the global analysis of miRNAs, molecules known to be key for eukaryotic gene regulation, has been limited in B. distachyon to studies examining a few samples or that rely on computational predictions. Similarly an in-depth global analysis of miRNA-mediated target cleavage using parallel analysis of RNA ends (PARE) data is lacking in B. distachyon. Results: B. distachyon small RNAs were cloned and deeply sequenced from 17 libraries that represent different tissues and stresses. Using a computational pipeline, we identified 116 miRNAs including not only conserved miRNAs that have not been reported in B. distachyon, but also non-conserved miRNAs that were not found in other plants. To investigate miRNA-mediated cleavage function, four PARE libraries were constructed from key tissues and sequenced to a total depth of approximately 70 million sequences. The roughly 5 million distinct genome-matched sequences that resulted represent an extensive dataset for analyzing small RNA-guided cleavage events. Analysis of the PARE and miRNA data provided experimental evidence for miRNA-mediated cleavage of 264 sites in predicted miRNA targets. In addition, PARE analysis revealed that differentially expressed miRNAs in the same family guide specific target RNA cleavage in a correspondingly tissue-preferential manner. Conclusions: B. distachyon miRNAs and target RNAs were experimentally identified and analyzed. Knowledge gained from this study should provide insights into the roles of miRNAs and the regulation of their targets in B. distachyon and related plants. © 2013 Jeong et al.