Project description:Increasing concern about pollution of our environment calls for advanced and rapid methods to estimate ecological toxicity. The use of gene expression microarrays in environmental studies can potentially meet this challenge. We present a novel method to examine soil toxicity. We exposed the collembolan Folsomia candida to soil containing an ecologically relevant cadmium concentration, and found a cumulative total of 1586 differentially expressed transcripts across three exposure durations, including transcripts involved in stress response, detoxification, and hypoxia. Additional enrichment analysis of gene ontology (GO) terms revealed that antibiotic biosynthesis is important at all time points examined. Interestingly, genes involved in the "penicillin and cephalosporin biosynthesis pathway" have never been identified in animals before, but are expressed in F. candida’s tissue. The synthesis of antibiotics can possibly be a response to increased cadmium-induced susceptibility to invading pathogens, which might be caused by repression of genes involved in the immune-system (C-type lectins and Toll receptor). This study presents a first global view on the environmental stress response of an arthropod species exposed to contaminated soil,and provides a mechanistic basis for the development of a gene expression soil quality test. Keywords: cadmium, soil, Collembola, environmental genomics
Project description:Temperature is an important ecological condition, and sudden temperature changes in soil can induce stress in soil-dwelling invertebrates. Soil animals can move to more favorable habitats and/or adapt physiologically to a stressful environment. Hyperthermic conditions will impact gene expression as one of the first steps. We use a transcriptomics approach to identify the transcripts of which expression changed in response to heat stress in the springtail Folsomia candida using a 5,131 probe microarray. A temperature shift from 20°C to 30°C for 30 minutes significantly altered the expression of 142 genes, of which 116 were upregulated, and 26 downregulated. Many upregulated genes encoded heat shock proteins (Hsps) or enzymes involved in the synthesis of ATP, such as members of the electron transport chain. Furthermore, genes involved in oxidative stress and anion-transporting ATPases were upregulated. Downregulated were glycoside hydrolases, involved in catalysis of certain disaccharides, which indicate an accumulation of stress-protective disaccharides. The microarray results from this study, which were validated using quantitative RT PCR, reveal a mild response to heat shock in this soil invertebrate, relative to other organisms. This may be due to specific ecological factors during evolution of soil invertebrates, such as the relatively stable temperatures in the soil habitat. This study presents potential candidate genes for future functional studies concerning thermal stress in soil-dwelling invertebrates, like e.g., the investigation of the heat hardening process.
Project description:Polycyclic aromatic hydrocarbons are common pollutants in soil, have negative effects on soil ecosystems, and are potentially carcinogenic. The Springtail (Collembola) Folsomia candida is often used as an indicator species for soil toxicity. Here we report a toxicogenomic study that translates the ecological effects of the polycyclic aromatic hydrocarbon phenanthrene in soil to the early transcriptomic responses in Folsomia candida. Microarrays were used to examine two different exposure concentrations of phenanthrene, namely the EC10 (24.95 mg kg-1 soil) and EC50 (45.80 mg kg-1 soil) on reproduction of this springtail, which evoked 405 and 251 differentially expressed transcripts, respectively. Fifty transcripts were differential in response to either concentration. Many transcripts encoding xenobiotic detoxification and biotransformation enzymes (phases I, II, and III) were upregulated in response to either concentration. Furthermore, indications of general and oxidative stress were found in response to phenanthrene. Chitin metabolism appeared to be disrupted particularly at the low concentration, and protein translation appeared suppressed at the high concentration of phenanthrene; most likely in order to reallocate energy budgets for the detoxification process. Finally, an immune response was evoked especially in response to the high effect concentration, which was also described in a previous transcriptomic study using the same effect concentration (EC50) of cadmium. Our study provides new insights in the molecular mode of action of the important polluting class of polycyclic aromatic hydrocarbons in soil animals. Furthermore, we present a fast, sensitive, and specific soil toxicity test which enhances traditional tests and may help to improve current environmental risk assessments and monitoring of potentially polluted sites.
Project description:Narcosis or baseline toxicity is the inert toxicity of hydrophobic compounds, supposed to take place at the level of the cellular membranes. Based on the linear relationship between the toxicity (logEC50) and the hydrophobicity (logKow), class I and II narcotizing compounds are recognized, in which the latter group is assumed to exert additional toxic mechanisms by hydrogen bond donor acidity by their polar groups. Chlorinated anilines, which occur often in the environment as degradation products of certain pesticides , are considered to be narcotizing compounds. In this study the transcriptional responses of the soil arthropod Folsomia candida are investigated upon exposure to a series of anilines with increasing chlorination. A discrimination between class1 and class2 narcotizing compound is being made.
Project description:Polycyclic aromatic hydrocarbons are common pollutants in soil, have negative effects on soil ecosystems, and are potentially carcinogenic. The Springtail (Collembola) Folsomia candida is often used as an indicator species for soil toxicity. Here we report a toxicogenomic study that translates the ecological effects of the polycyclic aromatic hydrocarbon phenanthrene in soil to the early transcriptomic responses in Folsomia candida. Microarrays were used to examine two different exposure concentrations of phenanthrene, namely the EC10 (24.95 mg kg-1 soil) and EC50 (45.80 mg kg-1 soil) on reproduction of this springtail, which evoked 405 and 251 differentially expressed transcripts, respectively. Fifty transcripts were differential in response to either concentration. Many transcripts encoding xenobiotic detoxification and biotransformation enzymes (phases I, II, and III) were upregulated in response to either concentration. Furthermore, indications of general and oxidative stress were found in response to phenanthrene. Chitin metabolism appeared to be disrupted particularly at the low concentration, and protein translation appeared suppressed at the high concentration of phenanthrene; most likely in order to reallocate energy budgets for the detoxification process. Finally, an immune response was evoked especially in response to the high effect concentration, which was also described in a previous transcriptomic study using the same effect concentration (EC50) of cadmium. Our study provides new insights in the molecular mode of action of the important polluting class of polycyclic aromatic hydrocarbons in soil animals. Furthermore, we present a fast, sensitive, and specific soil toxicity test which enhances traditional tests and may help to improve current environmental risk assessments and monitoring of potentially polluted sites. Folsomia candida was exposed to phenanthrene spiked soil or untreated (reference/control) soil for 2 days. Two different concentrations of phenanthrene were used, 24.95 and 45.80 mg/kg soil which represent the EC10 and EC50 on reproduction, respectively. For each concentration treatment 4 biological replicates were used, replicate samples consisted of total RNA extracted from ~30 animals exposed in the same jar to either reference or phenanthrene spiked soil. Phenanthrene treated samples were always hybridized to reference samples in an evenly distributed dye-swap manner, which resulted in total in 8 hybridizations of 16 samples.
Project description:The present invention relates to methods for determining soil quality, and especially soil pollution, using the invertebrate soil organism Folsomia candida also designated as springtail. Specifically, the present invention relates to a method for determining soil quality comprising: contacting Folsomia Candida with a soil sample to be analysed during a time period of 1 to 5 days; isolating said soil contacted Folsomia Candida; extracting RNA from said isolated soil contacted Folsomia Candida; determing a gene expression profile based on said extracted RNA using microarray technology; comparing said gene expression profile with a reference gene expression profile; and determing soil quality based expression level differences between said gene expression profile and said control expression profile.
Project description:Temperature is an important ecological condition, and sudden temperature changes in soil can induce stress in soil-dwelling invertebrates. Soil animals can move to more favorable habitats and/or adapt physiologically to a stressful environment. Hyperthermic conditions will impact gene expression as one of the first steps. We use a transcriptomics approach to identify the transcripts of which expression changed in response to heat stress in the springtail Folsomia candida using a 5,131 probe microarray. A temperature shift from 20°C to 30°C for 30 minutes significantly altered the expression of 142 genes, of which 116 were upregulated, and 26 downregulated. Many upregulated genes encoded heat shock proteins (Hsps) or enzymes involved in the synthesis of ATP, such as members of the electron transport chain. Furthermore, genes involved in oxidative stress and anion-transporting ATPases were upregulated. Downregulated were glycoside hydrolases, involved in catalysis of certain disaccharides, which indicate an accumulation of stress-protective disaccharides. The microarray results from this study, which were validated using quantitative RT PCR, reveal a mild response to heat shock in this soil invertebrate, relative to other organisms. This may be due to specific ecological factors during evolution of soil invertebrates, such as the relatively stable temperatures in the soil habitat. This study presents potential candidate genes for future functional studies concerning thermal stress in soil-dwelling invertebrates, like e.g., the investigation of the heat hardening process. Folsomia candida was first acclimated to LUFA 2.2 soil at 20 C for two days. Then animals were either exposed to 30 C for 30 minutes (heat shock treated), or were not heat shocked (reference). For each treatment 4 biological replicates were used, replicate samples consisted of total RNA extracted from ~30 animals exposed in the same jar to either reference or heat shock. Each unique heat shock treated sample was hybridized to a unique reference sample. In total in 4 hybridizations of 8 samples, was performed. The dyes were evenly distributed, which means that for each treatment two samples were labeled with cy3 and the other two with cy5.
Project description:Narcosis or baseline toxicity is the inert toxicity of hydrophobic compounds, supposed to take place at the level of the cellular membranes. Based on the linear relationship between the toxicity (logEC50) and the hydrophobicity (logKow), class I and II narcotizing compounds are recognized, in which the latter group is assumed to exert additional toxic mechanisms by hydrogen bond donor acidity by their polar groups. Chlorinated anilines, which occur often in the environment as degradation products of certain pesticides , are considered to be narcotizing compounds. In this study the transcriptional responses of the soil arthropod Folsomia candida are investigated upon exposure to a series of anilines with increasing chlorination. A discrimination between class1 and class2 narcotizing compound is being made. Twenty-three day old Folsomia candida were exposed in LUFA 2.2 standard soil for two days to the EC50 concentrations of the following compounds: aniline, 4-chloroaniline, 3.5-dichloroaniline, 2,3,4-trichloroaniline, 2,3,5,6-tetrachloroaniline, pentachloroaniline and 1,2,3,4-tetrachlorobenzene.1,2,3,4-tetrachlrobenzene was included in the experimental design as a posiitive control of a narcotic class 1 compound. Four biological replicates were used for every treatment and a dye swap was used with the Cy3/Cy5 labels. This resulted in 32 samples which were analysed in 16 hybridisations executed in an interwoven loop design. The solvent (for spiking the soil) control was used as the reference treatment in the data analysis.
Project description:The influence of long-term copper contaminated agricultural soil at different pH levels on microbial communities and springtail transcriptional regulation
Project description:Natural toxins, such as isothiocyanate (ITC), are harmful secondary metabolites produced by plants. Many natural toxins occur in commercial crops, yet their possible negative repercussions on especially non-target soil organisms are largely unknown. This study examined molecular effects of 2-phenylethyl ITC on the soil arthropod species: Folsomia candida. Complementing ecotoxicological experiments with gene expression profiling allows the study of the underlying modes of action of toxins. For this the standardized ISO guideline for ecotoxicological experiments and a microarray for F. candida (GPL7150) were used. Toxic effects on reproduction were shown for F. candida, with EC50 values of around 11.5 nmol/g soil, illustrating the toxic character of this compound. A total of 130 genes were significantly differentially expressed between C and AC. The compounds were spiked in with acetone and due to the substantial difference between the two controls, only AC was chosen for further contrast analysis, comparing AC to EC10 and EC50 gene expressions. At EC10 level, 75 genes and at the EC50 level 107 genes were differentially expressed compared to AC. Approximately 36% of all significant genes could be annotated using Blast2GO. Gene expression profiles revealed the importance of lipid metabolism at low exposure concentrations (EC10), which is associated with the lipophilic nature of 2-phenylethyl ITC. At higher dosages (EC50) a wider array of genes was over-expressed, which included genes related to stress and sugar metabolism. Our study provides new insights in the molecular mode of action of a natural toxin soil animals. This study is the first step towards an understanding of these potential risks by studying the effects of a natural toxin at a life-history trait and molecular level.