Exploring DNA methylation patterns in copper exposed Folsomia candida and Enchytraeus crypticus

Accumulating evidence shows that epigenetics-mediated phenotypic plasticity plays a role in an organism’s ability to deal with environmental stress. However, to date, the role of epigenetic modifications in response to stress is hardly investigated in soil invertebrates. The main objective of this proof of principle study was to explore whether total cytosine and locus-specific CpG methylation are present in two important ecotoxicological model organisms, the springtail Folsomia candida and the potworm Enchytraeus crypticus, and if so, whether methylation patterns might change with increased toxicant exposure. LC-MS/MS analyses and bisulfite sequencing were performed to identify the CpG methylation state of the organisms. We show here, for the first time, a total level of 1.4% 5-methyl cytosine methylation in the genome of E. crypticus, and an absence of both total cytosine and locus-specific CpG methylation in F. candida. In E. crypticus, methylation of CpG sites was observed in the coding sequence (CDS) of the housekeeping gene Elongation Factor 1α, while the CDS of the stress inducible Heat Shock Protein 70 gene almost lacked methylation. This confirms previous observations that DNA methylation differs between housekeeping and stress-inducible genes in invertebrates. DNA methylation patterns in E. crypticus were not affected by exposure to copper (II) sulfate pentahydrate (CuSO4·5H2O) mixed in with LUFA 2.2 soil at sublethal effect concentrations that decreased reproduction by 10%, 20% and 50%. Although, differences in CpG methylation patterns between specific loci suggest a functional role for DNA methylation in E. crypticus, genome-wide bisulfite sequencing is needed to verify whether environmental stress affects this epigenetic hallmark

Enchytraeus crypticus as model species in soil ecotoxicology.

Enchytraeids are ecologically relevant soil organisms, due to their activity in decomposition and bioturbation in many soil types worldwide. The enchytraeid reproduction test (ERT) guidelines ISO 16387 and OECD 220 are exclusive to the genus Enchytraeus and recommend using the species E. albidus with a 6-week test period. The suggested alternative, E. crypticus has a shorter generation time which may enable the ERT to be twice as fast. To confirm the suitability of a 3-week test period for E. crypticus, the toxicity of five chemicals, with distinct properties and modes of action, was assessed in LUFA 2.2 soil. In all controls the validity criteria were met, as survival of E. crypticus was above 92% and more than 772 juveniles were produced. The good performance supports its appropriateness as model species. Reproduction was more sensitive than survival, with only cadmium and 3,5-dichloroaniline causing significant lethal effects in the tested concentration ranges. The effect concentration causing 50% reduction in the number of juveniles (EC50) was 35mgk

Toxicity and bioaccumulation of phenanthrene in Enchytraeus albidus (Oligochaeta: Enchytraeidae)

Polycyclic aromatic compounds, such as phenanthrene (PHE), tend to accumulate in the soil compartment, where they may be retained for many years because of their persistency and hydrophobicity. The toxicity and bioaccumulation of these chemicals in soil biota and potential biomagnification along the food chain is an issue of concern. The main goal of this study was to determine the toxicity and bioaccumulation of PHE in Enchytraeus albidus (Oligochaeta: Enchytraeidae) in a natural standard soil (LUFA 2.2) following standard test guidelines. Phenanthrene dose-relatedly affected the survival and reproduction of E. albidus with median lethal concentration and median effective concentration (EC50) values of 135 and 33mg/kg dry soil, respectively. A toxicokinetics study, performed at a nontoxic soil concentration of 8mg/kg, showed uptake and elimination rate constants of 4.91kg soil per kilogram fresh weight animal per day and 0.236 per day, respectively and a bioaccumulation factor (BAF) of 20.8kg soil per kilogram fresh weight animal. These results show that the three-week exposure in the toxicity test with E. albidus is sufficiently long to reach equilibrium, but also that PHE may accumulate to considerable levels, possibly causing a risk for predators. © 2010 SETAC © 2011 SETAC

Development of ecosystems to climate change and the interaction with pollution-Unpredictable changes in community structures

Climate change has serious impacts on ecosystems, e.g. species diversity and abundance. It is well known that changes in temperature may have a pronounced influence on the reproductive output, growth and survival of various terrestrial species. However, much less is known on to how changes in temperature combined with exposure to pollution will influence biodiversity, the interaction between species, and the resulting change in species composition. In order to understand the effects of changes in temperature and copper pollution (individually and in combination) on soil communities and processes, a factorial multispecies experiment was performed. Six animal species (representing different functional groups) were exposed in control (30. mg. Cu/kg) and copper-contaminated soil (1000. mg. Cu/kg) to four temperatures (10, 14, 19, and 23. ??C) representing the "summer" range (low to high) for Denmark, and three exposure periods (28, 61, and 84 days). The species composition, feeding activity and OM turnover were assessed throughout. Multivariate analysis displayed significant changes in the food-web both with different copper levels and temperatures, resulting in different species composition for each exposure scenario. The most important species were Enchytraeus crypticus (most sensitive to copper and temperature) and Folsomia candida (most abundant). Major changes in abundance due to temperature occurred in the first 28 days of exposure, where population growth was higher. A temperature dependent population growth rate could be modeled for an exposure period of 28 days, whereas after 61 and 84 days of exposure the data did not fit the model. Especially for treatments that also included Cu, modeling of the population growth was no longer possible. The results of our study indicate that when climate change occurs in polluted areas, the consequences on populations cannot be predicted based on data from non-polluted areas. The risk may be synergistic for certain species, as indicated in the present study, and the final balance may depend on the particular species composition of that ecosystem

Suscetibilidade de linhagens de frangos de corte à síndrome ascítica Ascites syndrome effects in different commercial broilers

O objetivo deste trabalho foi estudar a suscetibilidade à síndrome ascítica de machos e fêmeas em linhagens comerciais de frango de corte. Todas as aves receberam ração ad libitum com 3.050 kcal/ME. Foram comparadas as linhagens comerciais representadas pela Cobb, Hubbard e Ross, machos e fêmeas. O delineamento utilizado foi o inteiramente casualizado, em esquema fatorial. As aves foram aleatoriamente alojadas em um galpão experimental de 8x76 m, com 18 boxes de 3x3,5 m cada e 100 aves por divisão, num total de 1.800 aves. Os resultados revelaram que a incidência de ascite independe da linhagem comercial dos frangos de corte, entretanto, os machos foram mais suscetíveis.<br>The objective of this work was to verify the incidence of ascites in males and females on commercial lines of broilers. All birds received ration ad libitum with 3,050 kcal/ME. The commercial lines Cobb, Hubbard and Ross, males and females, were compared. A factorial design was used with three replications per treatment. A total of 1,800 birds were housed at random in an experimental shed of 8x76 m, with 18 compartments of 3x3.5 m each and 100 birds per division. The results showed that the incidence of ascites was independent of the commercial broiler line, however, males were more susceptible