Technique of Earthworms Restoring Soil in Greenhouse Cultivation

The production environment of greenhouse cultivation is relatively closed,the multiple cropping index is high,the management of fertilizationwatering and pesticideapplication isblindtosomeextent,andthe phenomenonofcontinuous cropping isalsocommonSoilquali-ty affects the sustainable development of greenhouse cultivation.Earthworm is a ubiquitous invertebrate organism in soil,an important part of soil system,a link between terrestrial organisms and soil organisms,an important link in the small cycle of soil material organisms,and plays an important role in maintaining the structure and function of soil ecosystem.Different ecotypes of earthworms are closely related to their habi-tats(soil layers)and food resource preferences,and then affect their ecological functions.The principle of earthworm regulating soil function is essentially the close connection and interaction between earthworm and soil microorganism.Using different ecotypes of earthworms and bio-logical agents to carry out combined remediation of greenhouse cultivation soil is a technical model to realize sustainable development of green-house cultivation.

Study on the Acute Toxicity of Rare Earth Yttrium to Earthworms under the Stress of Leaching Agent Ammonium Sulfate

This study aimed to investigate the toxicity of rare earth ion yttrium under the stress of leaching agent ammonium sulfate （NH4）2SO4. [Method] By using earthworms as indicator organisms of environmental pol ution, acute toxic ef-fects of rare earth yttrium on earthworms under the stress of ammonium sulfate were investigated with filter paper contact method. [Result] Under single stress of rare earth yttrium, the semi-lethal concentration after 48 and 24 h was LC50=213.41 mg/L and LC50=322.63 mg/L, respectively. ② Under single stress of ammonium sul-fate, the semi-lethal concentration after 48 h and 24 h was LC50=13.89 g/L and LC50=15.05 g/L, respectively. ③ In combined treatment of low concentration （10 g/L） of ammonium sulfate and different doses of rare earth yttrium, the semi-lethal con-centration after 48 and 24 h was LC50=198.65 g/L and LC50=399.85 g/L, respective-ly; in combined treatment of middle concentration （14 g/L） of ammonium sulfate and different doses of rare earth yttrium, the semi-lethal concentration after 48 and 24 h was LC50=167.3 mg/L and LC50=256.73 mg/L, respectively; in combined treatment of high concentration （20 g/L） of ammonium sulfate and different doses of rare earth yttrium, the semi-lethal concentration after 48 h and 24 h was LC50=31.03 mg/L and LC50=127.65 mg/L, respectively. [Conclusion] Low concentration of ammonium sulfate could reduce the toxicity of rare earth yttrium to earthworms and produce certain antagonism against rare earth yttrium; middle concentration ammonium sulfate in-creased the toxicity of rare earth yttrium to earthworms and produced relatively sig-nificant synergistic effects; high concentration ammonium sulfate significantly in-creased the toxicity of rare earth yttrium to earthworms. Compared with ammonium sulfate, dead earthworms exposed to rare earth yttrium were more easily fractured, and living earthworms showed insensitive response to acupuncture.

Earthworms: Charles Darwin’s ‘Unheralded Soldiers of Mankind’: Protective &Productive for Man &Environment

Earthworms promises to provide cheaper solutions to several social, economic and environmental problems plaguing the human society. Earthworms can safely manage all municipal and industrial organic wastes including sewage sludge and divert them from ending up in the landfills. Their body work as a ‘biofilter’ and they can ‘purify’ and also ‘disinfect’ and ‘detoxify’ municipal and several industrial wastewater. They reduce the BOD & COD loads and the TDSS of wastewater significantly. They can even remove the EDCs (endocrine disrupting chemicals) from sewage which is not removed by the conventional sewage treatments plants. Earthworms can bio-accumulate and bio-transform many chemical contaminants including heavy metals and organic pollutants in soil and clean-up the contaminated lands for re-development. Earthworms restore & improve soil fertility by their secretions (growth hormones) and excreta (vermicast with beneficial soil microbes) & boost ‘crop productivity’. They have potential to replace the environmentally destructive chemical fertilizers from farm production. The ‘protein rich’ earthworm biomass is being used for production of ‘nutritive feed materials’ for fishery, dairy & poultry industries. They are also being used as ‘raw materials’ for rubber, lubricant and detergent industries. The bioactive compounds isolated from earthworms are finding new uses in production of ‘life saving medicines’ for cardiovascular diseases and cancer cure.

Earthworms' Transcriptome and Gut Microbiota Response to Mineral Weathering

1 Introduction Earthworms are an important component of soil macrofauna,dominating the biomass of soil invertebrates(Kodama et al.,2014;Plum and Filser,2005).They are known as the"engineers of ecosystem",and have a

Response of Nitrous Oxide Flux to Addition of Anecic Earthworms to an Agricultural Field

The burrowing and feeding activities of earthworms may have a strong effect on the flux of N2O from agricultural soils. As such, shifts to agricultural management practices that increase the number of earthworms require an understanding of the role of earthworms in N2O dynamics. We conducted a field experiment to examine the effects of addition of anecic earthworms (Lumbricus terrestris) on N2O flux in a field previously planted with corn (Zea mays) in southern Rhode Island, USA. Plots were amended with (15NH4)2SO4 and either 0 (CTL) or 48 L. terrestris m-2 (EW). The flux of N2O, 15N2O and 15N2 was measured over 28 days between October and November 2008. The EW treatment had a significantly higher flux of N2O and 15N2O 1 - 3 days after 15NH4 addition. No treatment effects were observed on 15N2 flux. The addition of earthworms significantly increased (Day 1) and decreased (Day 12) the mole fraction of N2O relative to the CTL. Our results suggest that anecic earthworm additions can increase N2O flux from inorganic fertilizer N amendments, but the effects appear to short-lived.

Transformation of Carbon and Nitrogen by Earthworms in the Decomposition Processes of Broad-leaved Litters

Earthworms are the important constituents in the decayed food web and the main ecological conditioners in the process of decomposition and nutrient mineralization. The transformation of organic carbon (C) and total nitrogen (N) in the broad-leaved litters ingested by earthworms was researched by means of a laboratory experiment. Experimental samples were collected from broad-leaved Korea Pine mixed forest in Liangshui National Natural Reserve (47°10′50″N, 128°53′20″E) in the northeastern Xiao Hinggan Mountains of Northeast China. The contents of organic C and total N in earthworms, leaf litters and earthworm faeces were analyzed. Results show that the organic C content was in the fol- lowing order: leaf litters>faeces>earthworms, while total N content was contrary to that of the organic C. The organic C contents in the different leaf litters were in the following order: Tilia amurensis>Betula costata>Acer mono, whereas the total N contents in the different leaf litters were: Betula costata>Tilia amurensis>Acer mono. The contents of organic C and total N in the faeces from the different leaf litters were almost consistent with the contents of the leaf litters. After the leaf litters were ingested by earthworms, the organic C, which was transformed to increase earthworms' weights, ac- counted for 3.90%-13.31% of the total ingestion by earthworms, while that in the earthworm faeces accounted for 6.14%-13.70%. The transformed organic C through the other metabolism (e.g., respiration) of earthworms accounted for 75.04%-89.92%. The ingested organic C by earthworms was mostly used for metabolic activities. The N ingested by earthworms was less than organic C. It is estimated that 37.08% of total N was transformed to increase the earthworm's weight, 19.97% into earthworm faeces and 47.86% for the consumption of the earthworm's activities. The earthworms not only increased the content of organic C and total N in the soil, but also decreased the values of C/N in the soil and leaf litters. Earthworms play a major role in the leaf litters' decomposition and transformation.

Organic Matter Decomposition in Red Soil as Affected by Earthworms

The earthworms Pheretima carnosaf Drawida gisti and Eisenia foetida were studied to compare theircontributions to the decomposition of various organic materials surface-applied on red soil in a 165-daygreenhouse experiment. The native species Pheretima caruosa and Drawida gisti were equally effective inaccelerating the decomposition of maize residue, according to fresh body weight, while commercial speciesEisenia foetida had no significant influence on dry mass loss of maize residue. Liming with CaCO3 or CaOshowed little effect on maize residue breakdown involved by Pheretima carnosal but it inhibited this processinvolved by Drawida gisti. The capability of Pheretima carnosa to the decomposition of five kinds of organicmaterials was thoroughly examined. The dry mass losses in worm treatments were in the order of soybeanresidue > maize residue > pig manure > semi-decayed maize > ryegrass. However, the relative contributionsof the earthworm to dry mass loss were in the order of pig manure (89.8%) > semi-decayed maize residue(49.1%) > maize residue (29.4%) > soybean residue (20.9%) > ryegrass residue (16.5%). Pheretima carnosaconsumed 20~120 mg dry weight of organic material per gram fresh weight of biomass per day.

Responses of Earthworms to Organic Matter at Different Stages of Decomposition

This study was conducted to examine the responses of earthworms to soil organic matter and litter at different decomposition stages and their contributions in litter decomposition processes in southern subtropical areas of China. Two plantations were selected as the study sites: Site I was dominated by the exotic endogeic earthworm species Ocnerodrilus occidentalis; Site II was dominated by epigeic species Amynthas corticis. After the fallen litter and earthworms were removed or expelled, four treatments were set up as: reserving the top soil (0–5 cm, equal to H layer) (H), removing the top soil and adding fresh litter (Le), removing the top soil and adding semi-decomposed litter (Li), and a control with no top soil nor any litter (CK). Five randomized blocks that were enclosed with nylon nets on the top were set up in each site, and then the four treatments were arranged randomly in each block. After 2–3 months, earthworms were collected using the formalin method. The results showed that Ocnerodrilus occidentalis preferred Treatment H though it was found in Treatments Le and Li as well; Amynthas corticis preferred Treatment Li though sometimes it also appeared in Treatment H; and Amynthas sp., another epigeic species, was mainly present under Treatment Le and only appeared in Treatment H occasionally. These findings confirmed that earthworm species belonging to different ecological groups had different responses to organic matter at different decomposition stages. The impacts of earthworm communities dominated by O. occidentalis mainly appeared at the later periods of litter decomposition.

Interaction between Earthworms and Arbuscular Mycorrhizal Fungi in Plants:A Review

Different kinds of soil animals and microorganisms inhabit the plant rhizosphere,which function closely to plant roots.Of them,arbuscular mycorrhizal fungi(AMF)and earthworms play a critical role in sustaining the soilplant health.Earthworms and AMF belong to the soil community and are soil beneficial organisms at different trophic levels.Both of them improve soil fertility and structural development,collectively promoting plant growth and nutrient acquisition capacity.Earthworm activities redistribute mycorrhizal fungi spores and give diversified effects on root mycorrhizal fungal colonization.Dual inoculation with both earthworms and AMF strongly magnifies the response on plant growth through increased soil enzyme activities and changes in soil nutrient availability,collectively mitigating the negative effects of heavy metal pollution in plants and soils.This thus enhances phytoremediation and plant disease resistance.This review simply outlines the effects of earthworms and AMF on the soil-plant relationship.The effects of earthworms on root AMF colonization and activities are also analyzed.This paper also summarizes the interaction between earthworms and AMF on plants along with suggested future research.

Effects of Cu Contamination on GSH- Px( Glutathione Peroxidase) Activity of Earthworms( Eisenia fetida ) in Soils

[ Objective] This study aimed to investigate the effects of Cu contamination in soils on GSH-Px （ glutathione peroxidase） activity of earthworms （ Eisenia fetida）. [ Method ] By artificial soil contamination method, changes in GSH-Px activity of earthworms under different Cu concentrations were investigated [ Result ] In the early exposure period, low-concentration Cu stress activated GSH-Px activity of earthworms to a certain extent; with the extension of extxqsure time and increase of Cu concentration, GSH-Px activity of earthworms showed a decreasing trend; however, under high-concentration Cu stress, there was no remarkable reg- ularity in the reduction of GSH-Px activity of earthworms. [ Conclusion] This study laid a solid foundation for further revealing the synergistic mechanism of antioxidant enzymes of earthworms.

Earthworms: A Source of Protein

Earthworms are important invertebrates that have been widely used as food and traditional medicine sources for thousands of years. Not only have researchers proven that earthworms are rich in proteins and other nutrients, they have also taken a keener interest in their unique pharmaceutical properties. Recent research has successfully discovered some beneficial functional components of earthworms due to the rapid development of biological technologies in the past decades. Therefore, earthworms could be a novel dietary supplement for human consumption. This review aims to summarize the current research about nutritional and therapeutic values of earthworms;and present a matured earthworm-derived product from Bocom Pharmaceuticals (USA) Corp as an example of its incorporation into a dietary supplement.

Effect of Earthworms on Removal of Pathogens during Stabilization of Industrial Organics

To investigate feasibility of pathogen free industrial organics with higher agronomic value, the industrial organic wastes were subjected to vermistabilization. The body of earthworm work as ＂biofilter＂ and they can ＂purify＂ and also ＂disinfect＂ and ＂detoxify＂ municipal and industrial organics. The microbiomics of gut and cast of earthworm （Eisenia foetida Savigny） and their association with vermistabilization was studied to determine the microbial quantification in reactors （industrial organics）. Worm were reared in five reactors viz. Sewage sludge （SS）, Paper mill industry sludge （PS）, Vegetable processing industry （VP）, Tannery waste （TW） and Meat process industrial sludge （MP） for ninety days. The microbial load （Salmonella, Shigella, Escherichia, Mycobacterium, Streptococcus） in gut and cast, biomass, recovery of cast in different reactors were determined, periodically. The microbiomics of worms gut revealed the removal of Salmonella （12-18 × 10^8±0.02 to 0-4 × 10^3 ＋ 0.05 CFU/g）, Shigella （14-23 × 10^8 ± 0.04 to 0-4 × 10^3 ± 0.05 CFU/g）, Escherichia （4-16 × 10^8 ± 0.02 to 0-4 × 10^2 ± 0.05 CFU/g）, Mycobacterium （3-16 × 10^8 ± 0.02 to 0-3 × 10^2 ± 0.05 CFU/g）, Streptococcus （6-16 × 10^8 ± 0.02 to 0-4 × 10^3 ± 0.05 CFU/g） during stabilization of industrial organics. Similarly, reduction in pathogens Salmonella （12-19 × 10^8 ± 0.02 to 0-8 ×10^3 ± 0.05 CFU/g）, Shigella （7-20× 10^8 ± 0.04 to 0-2 ×10^3 ± 0.05 CFU/g）, Escherichia （2-20 × 10^8 ± 0.02 to 0.0-2 × 10^3 ± 0.05）, Mycobacterium （1-8 × 10^8 ±0.05 to 0.0-5 × 10^2 ± 0.05 CFU/g）, Streptococcus （8-18 × 10^8 ± 0.02 to 0-7 × 10^3 ± 0.05 CFU/g） in castings of industrial organics indicates the selective nature of feeding of worm. This amply demonstrates that these pathogens have been eliminated as they entered in food chain of worms. However, it may not be possible to remove pathogens completely, but at least worms change the ＂microbial make-up＂ of industrial organics to make it harmless to the soil and enable its use as a nutritive organic fertilizer.

Optimizing biochar addition for vermicomposting:a comprehensive evaluation of earthworms’activity,N_(2)O emissions and compost quality

Biochar addition has been widely used in the field to mitigate soil nitrous oxide(N_(2)O)emissions,and can be considered as a potential method to reduce N_(2)O emissions during vermicomposting.However,excessive biochar addition may inhibit earthworms’activity.Thus,it is crucial to clarify the optimum addition volumes of biochar during vermicomposting.This study evaluated the impact of addition of various amounts of biochar(0,5,10,15,20 and 25%of total amount of feedstock)on earthworms’(Eisenia fetida)activity,N_(2)O emission and compost quality during vermicomposting.Compared with the treatment without biochar added,5%of biochar application significantly increased earthworm total biomass(from 177.5 to 202.2 g pot^(−1)),and cumulative burrowing activity(from 47.0%to 52.2%pixel per terrarium).The increased earthworms activity stimulated the vermicomposting process and led to the best quality of compost,which showed the highest total nutrient content(5.38%)and a significantly higher germination percentage of seeds(88%).Although N_(2)O emissions were slightly increased by 5%biochar addition,a nonsignificant difference was found between the treatment with 5%biochar and the treatment without biochar added.On the contrary,20%and 25%biochar addition not only lowered N_(2)O emissions,but also significantly decreased the quality of compost.The results suggest that 5%biochar application is an appropriate amount to improve the quality of compost without significant N_(2)O emissions.

Effect of arsenite on the proteome of earthworms Eisenia fetida

Arsenic(As)is broadly distributed due to natural and anthropogenic sources,and it is toxic to organisms.This study aimed to investigate the proteomic response in earthworm exposed to As^(3+).Earthworms were exposed to As^(3+)in soil at 5-80 mg kg1,and samples were collected after 60 days exposure.Two-dimensional electrophoresis(2-DE)was used to separate the proteins in earthworm homogenate,then differentially expressed proteins(DEPs)were identified using MALDI-TOF/TOF-MS analysis.After 2-DE,36 DEPs were found and 24 of them were successfully identified.79.2%of DEPs were upregulated compared to the control group.The maximum fold change reached 53.8 in spot 3108 in the 80 mg kg^(-1)As group.Two proteins were not found in the control group but found in the As treated groups.Proteins were grouped into metabolism,signal transduction,stress-related,transport,regulation,and predicted/hypothetical protein categories based on their function.The protein-protein interaction between the DEPs indicated that serum albumin(ALB)is very important,related to 6 other proteins.Proteins were then verified by western blot,the results were in agreement with the proteomic analyses.The identification of induced or repressed proteins because of As^(3+)in earthworms is helpful to explore the underlying mechanisms of soil arsenic ecotoxicity.

Combined effects of earthworms and biochar on PAHs-contaminated soil remediation:A review

Polycyclic aromatic hydrocarbons(PAHs)in soil pose a threat to the health of humans and other organisms due to their persistence.The remediation method of combined application of biochar and earthworms has received growing attention owing to its effectiveness in PAHs removal.However,the earthworm-biochar interaction and its influence on PAHs in soil has not been systematically reviewed.This review focuses on the effectiveness of combined application of earthworms and biochar in the remediation of PAHs-contaminated soils and the underlying mechanisms,including adsorption,bioaccumulation,and biodegradation.Earthworm-biochar interaction activates the functional microorganisms in soil and the PAHs-degrading microorganisms in earthworm guts,promoting PAHs biodegradation.This review provides a theoretical support for the combined application of biochar and earthworms in the remediation of PAHs-contaminated soils,points out the limitations of this remediation method,and finally shows the prospects for future research.

Pharmacological effects of bioactive agents in earthworm extract:A comprehensive review

This review compiles information from the literature on the chemical composition,pharmacological effects,and molecular mechanisms of earthworm extract(EE)and suggests possibilities for clinical translation of EE.We also consider future trends and concerns in this domain.We summarize the bioactive components of EE,including G-90,lysenin,lumbrokinase,antimicrobial peptides,earthworm serine protease(ESP),and polyphenols,and detail the antitumor,antithrombotic,antiviral,antibacterial,anti-i nflammatory,analgesic,antioxidant,wound-healing,antifibrotic,and hypoglycemic activities and mechanisms of action of EE based on existing in vitro and in vivo studies.We further propose the potential of EE for clinical translation in anticancer and lipid-modifying therapies,and its promise as source of a novel agent for wound healing and resistance to antibiotic tolerance.The earthworm enzyme lumbrokinase embodies highly effective anticoagulant and thrombolytic properties and has the advantage of not causing bleeding phenomena due to hyperfibrinolysis.Its antifibrotic properties can reduce the excessive accumulation of extracellular matrix.The glycolipoprotein extract G-90 can effectively scavenge reactive oxygen groups and protect cellular tissues from oxidative damage.Earthworms have evolved a well-developed defense mechanism to fight against microbial infections,and the bioactive agents in EE have shown good antibacterial,fungal,and viral properties in in vitro and in vivo experiments and can alleviate inflammatory responses caused by infections,effectively reducing pain.Recent studies have also highlighted the role of EE in lowering blood glucose.EE shows high medicinal value and is expected to be a source of many bioactive compounds.

Subtropical forest macro-decomposers rapidly transfer litter carbon and nitrogen into soil mineral-associated organic matter

Background:Forest soils in tropical and subtropical areas store a significant amount of carbon.Recent framework to assess soil organic matter(SOM)dynamics under evolving global conditions suggest that dividing bulk SOM into particulate and mineral-associated organic matter(POM vs.MAOM)is a promising method for identifying how SOM contributes to reducing global warming.Soil macrofauna,earthworms,and millipedes have been found to play an important role in facilitating SOM processes.However,how these two co-existing macrofaunae impac the litter decomposition process and directly impact the formation of POM and MAOM remains unclear.Methods:Here,we set up a microcosm experiment,which consisted of 20 microcosms with four treatments earthworm and litter addition(E),millipedes and litter addition(M),earthworm,millipedes,and litter addition(E+M),and control(only litter addition)in five replicates.The soil and litter were sterilized prior to beginning the incubation experiment to remove any existing microbes.After incubating the samples for 42 days,the litte properties(mass,C,and N contents),soil physicochemical properties,as well as the C and N contents,and POM and MAOM^(13)C abundance in the 0–5 and 5–10 cm soil layers were measured.Finally,the relative influences o soil physicochemical and microbial properties on the distribution of C and N in the soil fractions were analyzed Results:The litter mass,C,and N associated with all four treatments significantly decreased after incubation especially under treatment E+M(litter mass:-58.8%,litter C:-57.0%,litter N:-75.1%,respectively),while earthworm biomass significantly decreased under treatment E.Earthworm or millipede addition alone showed no significant effects on the organic carbon(OC)and total nitrogen(TN)content in the POM fraction,but join addition of both significantly increased OC and TN regardless of soil depth.Importantly,all three macrofauna treatments increased the OC and TN content and decreased the^(13)C abundance in the MAOM fraction.More than65%of the total variations in the distribution of OC and TN throughout the two fractions can be explained by a combination of soil physicochemical and microbial properties.Changes in the OC distribution in the 0–5 cm soi layer are likely due to a decrease in soil pH and an increase in arbuscular mycorrhizal fungi(AMF),while those in the 5–10 cm layer are probably caused by increases in soil exchangeable Ca and Mg,in addition to fungi and gram-negative(GN)bacteria.The observed TN distribution changes in the 0–5 cm soil likely resulted from a decrease in soil pH and increases in AMF,GN,and gram-negative(GP)bacteria,while TN distribution changes in the 5–10 cm soil could be explained by increases in exchangeable Mg and GN bacteria.Conclusions:The results indicate that the coexistence of earthworms and millipedes can accelerate the litte decomposition process and store more C in the MAOM fractions.This novel finding helps to unlock the processe by which complex SOM systems serve as C sinks in tropical forests and addresses the importance of soil mac rofauna in maintaining C-neutral atmospheric conditions under global climate change.

Earthworms promote the accumulation of rhizodeposit carbon to soil macroaggregate in a Mollisol of northeast China,primarily in long-term no-till soil

As soil ecosystem engineers,earthworms are the main promoters of soil aggregation,a process that drives the production of ecosystem services by soils.A crucial factor in the ecosystem service of carbon sequestration is rhizodeposit carbon,which is the main energy source of soil food webs.The effects of earthworms on the distribution of rhizodeposit-carbon in soil aggregates remain unclear.Here,we conducted a 13CO2 labeling experiment to determine the effects of earthworms on maize rhizodeposit carbon in soil aggregates after 14 years(2002-2016),in both conventional tillage(CT)and conservation tillage(no tillage,NT)soils.Four treatments were established in total:NTE(no tillage soil with earthworms),CTE(conventional tillage soil with earthworms),NTC(control,no tillage soil without earthworms),and CTC(control,conventional tillage soil without earthworms).Earthworms significantly enhanced the abundance of soil macroaggregates(>2000μm and 250-2000μm)on day 30 compared with day 2(after labeling),especially in the NTsoils.On day 30,in the presence of earthworms,the amounts of rhizodeposit carbon in the>2000μm and 250-2000μm soil aggregates in the NTsoils were significantly higher than in those in the CTsoils(P<0.05),and higherδ13C signatures in the same size aggregates were observed in the NT soils than in the CT soils(P<0.05).These findings indicated that compared with the CT soils,with the involvement of earthworm activity,the NT soils promoted more rhizodeposit carbon transformation to the soil macroaggregates.Our results clearly indicate that soil macroaggregates formed in different tillage soils in the presence of 2 different engineers(earthworms and roots)significantly differ from those formed in the presence of only one organism(roots)in the long term.

Evaluation of antioxidant enzymes performances and DNA damage induced by bisphenol A and diisobutylphthalate in Hyperiodrilus africanus-earthworms

Background:Bisphenol A(BPA)and diisobuthylphthalate(DIBP)have found wide applications as plasticizers;however,they are covalently bonded to materials and are subsequently leached into the environment.Methods:This study evaluated the effects of BPA,DIBP and mixtures of BPA and DIBP on the antioxidant enzymes[superoxide dismutase(SOD),peroxidase(POD)]activities using standard methods and DNA profile of earthworm(Hyperiodrilus africanus)using randomly amplified polymerase chain reaction(RAPD-PCR)method.A total of 2 kg soil samples collected from FADAMA Farm,Federal University of Agriculture,Abeokuta were spiked to obtain 1,2.5,5 and 10 ppm of BPA,DIBP and mixtures of BPA and DIBP.Earthworms were exposed to the unpolluted and spiked soil samples and were collected on the 7th and 14th day for SOD,POD and DNA analysis.Results:SOD activity was more pronounced at 5 and 10 ppm concentrations.POD activity was increased in all concentrations,including the control,meanwhile POD activity induced by BPA and DIBP was significantly higher(p<0.05)at 10 ppm compared to other concentrations.RAPD-PCR analysis revealed varying DNA fragment lengths due to excessive oxidative stress generated by the treatments,resulting in DNA damage.BPA and DIBP mixtures generated more fragments of DNA on day 14 than other treatments.Conclusions:This study established that antioxidant activity decreases with exposure time to BPA and DIBP,while DNA damage increases with exposure time.

Molecular toxicity of earthworms induced by cadmium contaminated soil and biomarkers screening

Earthworms （Eiseniafetida） were used to study the impact of low-dose cadmium in treated artificial soil （0, 0.6, 3, 6, 15, 30 mg/kg） and contaminated natural soil （1.46 mg/kg）. The changes of earthworms＇ physiological related gene expressions of metallothionein （MT）, armetocin, calreticulin and antimicrobial peptides were detected using real-time PCR after a 70-day incubation period. The results showed that low doses of cadmium could up regulate earthworms＇ MT and down regulate annetocin gene expression and show a significant positive and negative correlation respectively. The expression of two other genes, calreticulin and anti-microbial peptides, was induced at low doses of cadmium （highest gene expression at 0.6 mg/kg for calreticulin and 6 mg/kg for anti-microbial peptides） and inhibited at high doses. No significant correlation was found for these two genes. This study shows that MT and annetocin genes expression found in earthworms in contaminated soil have the potential to be developed as biomarkers of soil cadmium pollution.