Dissertations / Theses on the topic 'Earthworms'
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1
Butt, Kevin Richard. "An investigation into the growth and reproduction of the earthworm Lumbricus terrestris L. under controlled environmental conditions." Thesis, n.p, 1990. http://ethos.bl.uk/.
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Chen, Shing-Chong. "Enzyme Assays Using Earthworms for Assessing Innate and Nonspecific Immunotoxicity of Xenobiotics." Thesis, University of North Texas, 1992. https://digital.library.unt.edu/ark:/67531/metadc277598/.
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Principal objectives of my research were to: (1) report for the first time that coelomocytes are able to reduce NBT dye and confirm the presence of lysozyme-like activity in earthworm; (2) develop a standard methodology for determination of NBT reduction and lysozyme-like activity in earthworms; (3) compare NBT reduction and lysozyme-like activity in earthworms with those of murine and human cells and fluids; and (4) demonstrate the sensitivity of earthworm NBT reduction and lysozyme-like activity as the assays using matrics in refuse-derived fuel fly ash (RDFF) and CuSO4.
3
Yu, Shuo. "Bioaccumulation of Metals in Earthworms." The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1259697144.
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Gift, Danielle Marie. "Earthworms in the Urban Environment: Can Population Augmentation Improve Urban Soil Properties?" Thesis, Virginia Tech, 2009. http://hdl.handle.net/10919/34408.
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Urban forests perform essential ecological functions, and their performance is dependent on soil quality, which is often degraded by human activity. Because earthworms play a key role in soil health, augmenting earthworm populations in urban soils may improve tree performance. However, we know very little about earthworm ecology in highly urbanized soils. The objectives of our study were: (1) to assess earthworm demographics across a range of urban land uses and (2) to evaluate earthworm augmentation techniques for rehabilitating disturbed soils and improving tree growth.
- We conducted an observational study across three landuse types to assess earthworm abundance and diversity as well as associated soil properties. Earthworm abundance and biomass in were affected by land use type, disturbance time frame, and seasonality. Earthworm abundance and biomass were affected by a suite of complex soil and temporal variables, and soil temperature and moisture seemed to be the most influential properties.
- We conducted an earthworm inoculation experiment on a compacted cut-fill field soil with a very low existing earthworm population. In 2008, three soil treatments (control, compost, and compost + earthworm) were applied to 2 m2 plots into which two common urban tree species with contrasting soil tolerances were planted (Acer rubrum and Cornus florida). We measured soil physical and chemical properties along with earthworm survival and soil respiration. Earthworm inoculation did not succeed in improving bulk density or increasing soil organic matter, yet it was successful in increasing soil CEC, Fe, and Mn relative to compost only effects.
Master of Science
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Hariri, Maryam Feili. "Morphological and Immunological Characterization of Earthworm Lumbricus terrestris Coelomocytes." Thesis, University of North Texas, 1992. https://digital.library.unt.edu/ark:/67531/metadc798176/.
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This research defines the morphological characteristics of the immune cells, coelomocytes, of the earthworm, Lumbricus terrestris. Such a definition of coelomocyte morphology can be correlated with immune function which will be of value in the development of a nonmammalian surrogate system to assess the immunotoxic potential of a terrestrial xenobiotics. Earthworms exposed to artificial soil dilutions of two complex xenobiotic mixtures, refuse derived fuel fly ash and a Superfund sire soil demonstrated an enhanced ability to produce hemolytic factors.
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Buchheim, Caitlin M. "DIGESTION PROCESS IN LUBMRICUS TERRESTRIS ALTERS MICROBIAL ENZYME PRODUCTION AND SOIL NUTRIENTS." Miami University / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=miami1578657686503075.
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Simmons, Carla Stull. "Influence of copper on resistance of Lumbricus terrestris to bacterial challenge." Thesis, University of North Texas, 2000. https://digital.library.unt.edu/ark:/67531/metadc2602/.
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Earthworms, Lumbricus terrestris, were challenged orally and intracoelomically with two bacterial species, Aeromonas hydrophila and Pseudomonas aeruginosa, and mortality rates were observed. Neither were found to be particularly pathogenic at injected doses of up to 108 bacteria per earthworm. The influence of Cu++ (as CuSO4) on the earthworm's response to bacterial challenge was investigated by exposing earthworms to sublethal levels of Cu++ prior to bacterial challenge. Exposure at sublethal concentrations up to 3 m g/cm2 did not have a pronounced influence on host resistance to challenge as measured by earthworm mortality. Cu++ increased the earthworm's ability to agglutinate rabbit erythrocytes, indicating that Cu++ exposure caused coelomocyte death, autolysis and release of agglutinins into the coelom, possibly explaining resistance to bacterial challenge.
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Perreault, Jonathan M. "Casting activity of Lumbricid earthworms from temperate agroecosystems." Thesis, McGill University, 2005. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=82405.
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Earthworms are well known for their casting and burrowing activities which improve soil structure and soil fertility. However, earthworm populations in temperate regions exhibit patchy distribution in space and time. This makes it difficult to predict how earthworm activities may influence paedogenesis and nutrient cycling processes at the ecosystem level. The main objective of this study was to determine the spatiotemporal dynamic of surface cast production of two earthworm species, Aporrectodea turgida and Lumbricus terrestris, on the row-interrow scale in a temperate soybean agroecosystem. Our observations demonstrated that casting activity was synchronous with plant growth. More casts were also found in the row intercepts compared to the interrow ones. Both the spatial and temporal variations are thought to be caused by the microclimate found under the plant canopy, verifying results from controlled laboratory studies that show casting activity to be controlled by soil temperature and moisture. These results suggest a possible mutualism between earthworm and plants in cultivated temperate soybean agroecosystems, but this remained to be confirmed.
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Ricketts, Huw John. "Molecular genetic biomarkers of reproductive fitness in earthworms." Thesis, Cardiff University, 2004. http://orca.cf.ac.uk/55966/.
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When ecotoxicologists assess the environmental impact of pollution they must pose a fundamental question. That is, is the toxicological data produced from any experiment ecologically relevant It has long been thought that a measure of survival of any organism is not sufficient to predict potential population effects. A more sensitive method is the measurement of sub-lethal endpoints, such as growth and reproduction. However, measurement of these parameters may not give an 'early warning' of the impact of complex pollutants within any ecosystem. Therefore, so-called biomarkers have been developed to fill this void. Biomarkers can be used at a number of organisational levels e.g. cellular, protein or DNA, but they all have the sensitivity to act as predictive tools in ecotoxicology and risk assessment. In the past twenty years earthworms have become model organisms in terrestrial ecotoxicology. This is mainly due to the critical role they play within the soil ecosystem in most parts of the world. Therefore the present study utilises three earthworm species (Eisenia fetida, Eisenia andrei and Lumbricus rubellus) to identify, characterise and validate molecular genetic biomarkers of reproduction. To isolate potential reproductive genes a subtractive library was created from the anterior and posterior segments of Lumbricus rubellus. A number of potential biomarker candidate genes were identified, but a putative sperm-specific antigen warranted special attention. The gene fragment of this putative sperm antigen was identified in all three earthworm species used in the study and its potential as a biomarker is discussed. Annetocin has previously been characterised as a member of the mammalian vasopressin/oxytocin superfamily of neuropeptides and has been shown to induce egg-laying behaviours in Eisenia fetida. The annetocin gene was isolated from the three earthworm species and shown to be expressed in the reproductive segments of Eisenia fetida. The expression levels of the annetocin gene were determined in earthworms exposed to metalliferous soils both in laboratory and semi-field exposures using quantitative PCR. A decrease in annetocin gene expression levels correlated with a similar decrease in cocoon production rates of Eisenia fetida after metal exposure. Upon exposure to the mammalian steroid hormones, 17/3-oestradiol and testosterone along with the synthetic oestrogen 17a-ethynylestradiol, annetocin gene expression levels in Eisenia andrei were elevated in some cases, suggesting a role for oestrogens in earthworm reproduction. Eisenia andrei were also exposed to bisphenol A and nonylphenol in artificial soils and annetocin gene expression was determined. Although toxic to Eisenia andrei these two (weakly oestrogenic) compounds did not affect annetocin gene expression. These data strongly suggest that annetocin plays a critical role in earthworm reproduction and that oestrogens may modulate the expression of this gene. The annetocin genomic structure was determined and three oestrogen-responsive elements were identified within the promoter of the gene in Eisenia fetida. What is more, the genomic structure of annetocin conformed to the three exon, two intron model of vasopressin/oxytocin superfamily neuropeptides.
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Sizmur, Tom. "Impact of earthworms on metal mobility and availability." Thesis, University of Reading, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.553168.
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To assess the risks that contaminated soils pose to the environment properly a greater understanding of how soil biota influence the mobility of metal(loid)s in soils is required. Experiments have been undertaken to determine if earthworms affect the mobility, speciation and bioavailability of metals in contaminated soils. The majority of experiments involved inoculating Lumbricus terrestris (but also Eisenia veneta, Allolobophora chlorotica and Eisenia fetida) in laboratory microcosms containing soils contaminated with As, Cu, Pb and Zn. Metal(loid) availability to plants and mobility measured in porewater and soil extractions revealed that earthworms increased metal mobility, changed the speciation to a more available form and increased bioavailability to plants. The mechanism for these effects is the degradation of organic matter due to passage through the earthworm gut and subsequent release of organically bound metals into solution. Passage through the earthworm gut also increased the soil pH and the concentration of labile organic carbon which then had an impact on the distribution of metal(loid)s between the soil constituents and the soil solution. The precise effect depends on the chemistry of the element in question, but usually resulted in an increase in mobility. The secretion of earthworm mucus decreased the mobility of metals in soils, but this effect was not as great as passage through the earthworm gut. When earthworms were inoculated into soil that has been remediated with biochar and/or compost, they did not re-mobilise sequestered metals. Instead, the remedial amendment buffered the impact of the earthworm. The mobilisation of metal(loid)s in the environment by earthworm activity may allow for increased leaching or uptake into biota and should therefore be considered in the risk assessment of contaminated soils that contain earthworms.
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Kadir, Nawzad. "Plant mediated effects of earthworms on aphid dynamics." Thesis, University of Plymouth, 2014. http://hdl.handle.net/10026.1/3037.
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The individual and combined effects of the endogeic and epigeic groups of earthworms on the growth of Chinese cabbage (Brassica rapa), and on the subsequent growth and development of the generalist sap-sucking herbivore Myzus persicae were determined in separate pot experiments. Many previous studies have investigated the relationship between soil biodiversity and aboveground plants, but few researches have considered the indirect interaction between soil biota and above-ground aphids. In this study the individual effects of Aporrectodea rosea and Allolobophora chlorotica and the combined effects of A. rosea and A. chlorotica, Aporrectodea caliginosa and Satchellius mammalis, A. chlorotica and S. mammalis, and A. rosea, A. caliginosa, Lumbricus rubellus and S. mammalis on plant morphology and physiology and aphid development (nymphs day-1, fecundity and number of adults) were investigated. Plant growth was affected by the presence of A. rosea which caused increases in plant biomass, height of plant, leaf surface area and specific leaf area (SLA). Mean number of leaves per plant was unaffected by worm density. In contrast, increasing density of A. chlorotica had no effect on any aspect of plant performance. The combined effect of A. rosea and A. chlorotica resulted in a similar increase in plant biomass to A. rosea alone. While the combined effects of A. caliginosa and Satchellius mammalis, A. chlorotica and S. mammalis and A. rosea, A. caliginosa, L. rubellus and S. mammalis caused increases in all plant parameters except leaf number. Additionally, the individual effect of A. rosea and the combined effects of A. caliginosa and S. mammalis, A. chlorotica & S. mammalis and A. rosea and A. caliginosa, L. rubellus and S. mammalis resulted in increased in leaf nitrogen concentration. Aphid development was also affected by the presence of earthworms. The nymphs day-1, fecundity and numbers of adults were significantly increased with increases in earthworm densities. The interaction between all groups of earthworms and their influence on aphid growth showed that the combined effect of two different groups was greater than the individual groups. Proteomic techniques were used to compare protein patterns in the plants. The combined effects of A. caliginosa and S. mammalis, A. chlorotica and S. mammalis, A. rosea, A. caliginosa, L. rubellus and S. mammalis earthworms on plant resulted in differences in number and kind of protein between plant treated with earthworms and the control, but no significant difference in proteins volume. Effects of earthworms on plant growth and aphid development are shown to be modified by increasing density and interactions between different species and functional groups of earthworms.
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Cikutovic, Salas Marcos A. "Pathologies in earthworms: sublethal biomarkers of xenobiotic toxicity." Thesis, University of North Texas, 1991. https://digital.library.unt.edu/ark:/67531/metadc798085/.
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This research is part of an overall program to develop and use a suite of acute and sublethal toxicity biomarkers, and testing protocols for use in assaying potential effects of complex mixtures of xenobiotics such as found in soils containing agricultural biocides and petrochemical wastes dredged sediments, and hazardous waste sites (HWS). The purpose of this study was to evaluate four biomarkers of sublethal pathology that could be used in an integrative model of multiple toxicity endpoints with the earthworm Lumbricus terrestris.
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Mohammadian, Gholamreza. "Immunotoxicity of Chromium Contaminated Soil in the Earthworm, Lumbricus Terrestris." Thesis, University of North Texas, 1993. https://digital.library.unt.edu/ark:/67531/metadc501250/.
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Objective was to assess the toxicity of chromium (Cr) contaminated soil (CS) using the earthworm Lumbricus terrestris. Specific aims were to determine: (1) survival (LC50); .(2) immunotoxicity as indicated by lysozyme activity, coelomocyte counts, secretory (SR) and erythrocyte rosette (ER) formation, and phagocytosis; and (3) compare effects of CS exposure with those of Cr spiked artificial soil (AS) . CS Cr concentration was 8.78 mg/g with 98.2% being Cr^3+ and 1.8% being Cr^6+. Using 14 d AS protocol the LC50 was 6.49% CS: AS mixture. CS concentrations of 0.5, 1.0, 2.5 and 5.0% were sublethal, whereas 6.25, 12.5, 25, 50 and 100% CS were lethal. Sublethal exposure caused no immuno- modulation. Exposure to 50% CS: AS mixture for 5 d caused reduced SR and ER formation. Exposure to AS spiked with 0.27% Cr for 5 d resulted in immunomodulation equivalent to 50% CS: AS mixtures. Results indicated the CS to be acutely toxic.
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Chaoui, Hala I. "Separating earthworms from organic media using an electric field." Columbus, Ohio : Ohio State University, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1133296897.
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Suzuki, Yoshiaki, Teruo Matsubara, Mitsuo Hoshino, and 輝男 松原. "Breakdown of mineral grains by earthworms and beetle larvae." Elsevier, 2003. http://hdl.handle.net/2237/5300.
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Goats, Geoffrey Charles. "Assessment of the effects of toxic chemicals upon earthworms." Thesis, Imperial College London, 1985. http://hdl.handle.net/10044/1/37706.
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Bartlett, Mark D. "The ecology and control of earthworms on golf courses." Thesis, Cranfield University, 2006. http://dspace.lib.cranfield.ac.uk/handle/1826/7585.
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Earthworm casts on golf courses affect the playability of the turf and can potentially damage mowing equipment. Traditionally this problem has been limited using chemical controls. It is estimated that 0.6% of the total UK land surface is occupied by golf courses, therefore, the land management strategies which green keepers adopt with respect to the application of chemicals has a major environmental impact. The aim of this thesis was to investigate the ecology and potential control of earthworm casting in golf turf in environmentally sustainable ways. A quadrat survey of earthworm casts was conducted over two years at five golf courses in Bedfordshire and Buckinghamshire, UK. Using generalized linear models and forward multiple stepwise regression, an internally validated predictive model of earthworm casting activity was constructed. Annual activity on surfaces was predicted using five physicochemical parameters of which C: N and total inorganic nitrogen were the most important. Environmental parameters were also used to predict monthly earthworm activity, with evapotranspiration and rainfall representing the most significant variation. ' Mustard extraction surveys were used to investigate species diversity and community structure of earthworms. Four dominant species were identified (Aporrectodea rosea, Lunibricus rubellus, Aporrectodea longa and Lumbricus terrestris). It is likely that A. longa and L. terrestris, the two must abundant anecic forms, cause the greatest problems to green keepers as these are the largest of the four earthworm species. The microbial community of soil represents the earthworm's primary food source. An analysis of the microbial community size (using chloroform-extraction) and community structure (using phospholipid fatty acid [PLFA] analysis) showed that different surfaces found on golf courses supported significantly distinct and consistent microbial communities. Differences in population size and structure were evident at different depths through all golf course soil profiles investigated. Individual surface types were comparable, irrespective of geographical location. Therefore different surfaces and depths through the soil profile on golf courses represent different earthworm habitats. An investigation of the effects of different construction techniques and materials used in the golf industry on the rate of earthworm cast formation was made. This showed no effect of construction on the vertical distribution of earthworms, but the rate of casting increased on the sand dominated surfaces. It is proposed that this is due to the lower calorific value that this soil represents to the earthworms. This knowledge was applied in an earthworm cast mitigation experiment, reducing casting rates by stimulating the size of the microbial community with glucose solution. Control through physical exclusion of earthworms to the surface using a buried mesh was also trialled and significantly reduced earthworm casts, however no causal mechanism could be elucidated. This study has advanced the understanding of earthworm ecology on golf courses, deriving mechanistic understandings of this system as a whole. This will lead to a more environmentally sustainable approach to the control of earthworms on golf courses.
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Brooks, Geoffrey Lance. "Coelomic Fluid Protein Profile in Earthworms Following Bacterial Challenge." Thesis, University of North Texas, 2006. https://digital.library.unt.edu/ark:/67531/metadc5476/.
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Proteomic techniques were used to evaluate the protein profile of the earthworm, (Lumbricus terrestris), following a bacterial challenge. One control group received no injection; a second control group received injections of phosphate buffer solution (PBS). The experimental group received injections of PBS containing (Aeromonas hydrophila). After incubation for 12 hours at 20°C, coelomic fluid was collected from each group for analysis by 2-D electrophoresis. There were significant differences in spot appearance and density between control and experimental groups. Sixteen spots showed a two-fold increase in density and 63 showed at least a two-fold decrease in density between samples from control and bacteria-challenged earthworms, respectively, suggesting up- and down-modulation of proteins potentially involved in the earthworm's response to bacterial challenge.
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Voua, otomo Patricks. "The effects of long-term exposure to cadmium on the earthworm Eisenia Fetida (Oligochaeta) : an investigation of the development of genetic metal resistance." Thesis, Stellenbosch : Stellenbosch University, 2006. http://hdl.handle.net/10019.1/22010.
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Thesis (MSc)--University of Stellenbosch, 2006.ENGLISH ABSTRACT: The development of potential genetically based resistance to cadmium (Cd) after long-term exposure to this metal at a sublethal concentration, was investigated in earthworm specimens belonging to the genus Eisenia. Adult (clitellate) earthworms from a long-term laboratory Cdexposed population (> 78 generations) and from other populations having no previous history of metal exposure were exposed to increasing concentrations (0; 2.5; 5; 10 and 20 mg/l) of Cd in the form of CdSO4. Different biomarkers and molecular markers were used to determine whether the specimens from the long-term Cd-exposed population had acclimatized or adapted to the metal contaminated environment. Acclimation was investigated at different physiological and biochemical levels using the following three biomarkers: the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay (MTT assay) measuring mitochondrial activity and cell viability; the single cell gel electrophoresis assay (comet assay) measuring DNA strand breaks and the biosynthesis of metallothioneins (MTs) that have the function of lowering metal toxicity. Earthworms from the long-term exposed substrate as well as specimens from populations not exposed to Cd were used. Adaptation was investigated by looking at both allozyme polymorphism at seven enzyme encoding loci and DNA polymorphism using chosen neutral and selectable genetic markers. The markers used were cytochrome c oxydase subunit I (COI) and metallothionein-2 (mt-2) respectively. This was done amongst the same pool of populations. Additionally, the DNA polymorphism study also aimed at genetically identifying the species utilized in this study thereby determining whether these earthworms belong to the species Eisenia fetida or Eisenia andrei. MTs biosynthesis did not generate the expected data mainly due to the fact that a suitable antibody could not be obtained (discussed in Chapter 5 section 5.3.3.). Similarly, the assessment of DNA polymorphism at the chosen selectable genetic marker mt-2 did provide information relevant to understanding the potential development of resistance to Cd in the long-term metal contaminated group. COI sequences generated in this study were compared to E. fetida and E. andrei COI sequences available on Genbank. Consequently, specimens used in this study were identified as possibly belonging to the species E. andrei. Allozyme polymorphism revealed no fixed genetic differences between the long-term Cd exposed laboratory culture and the rest of the populations. All the populations departed from Hardy-Weinberg equilibrium (χ2 > 5.9; p < 0.05), and showed a low mean heterozygosity per locus (Ho ≤ 0.21), probably due to inbreeding. Cell viability and proliferation as tested by the MTT assay revealed that coelomocytes, isolated from the long-term Cd-exposed group showed the highest viability (98.42%) compared to those from other groups (+/- 80%). Kruskal-Wallis ANOVA (H2, 225=109.7165 p < 0.001) revealed that the long-term Cd-exposed laboratory culture showed a better response to acute exposure to Cd, thus demonstrating that these worms have developed some kind of tolerance to Cd. Similarly, the comet assay showed that in the long-term Cd-exposed specimens, less DNA breaks occurred after Cd exposure than in the unexposed groups. Of all the comet parameters assessed in this study (comet tail length, tail moment and tail DNA percentage), tail DNA percentage seemed to be more sensitive although all three parameters indicated that long-term Cd-exposed specimens were more resistant than unexposed specimens as shown by the number of single strand DNA breaks induced by exposure to higher concentrations of Cd (p < 0.001). The comet and the MTT assays indicated that the earthworms with a previous history of Cd exposure have developed increased fitness towards higher doses of Cd, compared to previously unexposed groups. These findings mainly proved that several mechanisms could come into play at the physiological and biochemical level to allow the Cd exposed population to acclimatize to its chemically stressful environment. Clear genetic support for the differences found between the tested populations was not obtained, but needs to be investigated further using Cd selectable markers such as the mt-2 gene, in order to come to a more conclusive deduction.
AFRIKAANSE OPSOMMING: Die moontlike ontwikkeling van geneties gebaseerde weerstand teen kadmium (Cd) by erdwurms van die genus Eisenia, na langtermyn blootstelling aan die metaal by 'n subletale konsentrasie, is ondersoek. Volwasse (klitellate) erdwurms van 'n langtermyn laboratorium Cdblootgestelde bevolking (< 78 generasies) asook van ander bevolkings met geen voorgeskiedenis van metaal blootstelling nie, is blootgestel aan 'n reeks van Cd konsentrasies (0; 2.5; 5; 10; en 20 mg/l) in die vorm van CdSO4. Verskillende biomerkers en molekulêre merkers is gebruik om vas te stel of die erdwurms geakklimeer of aangepas het by die metaal in die gekontamineerde omgewing. Akklimasie is op verskillende fisiologiese en biochemiese vlakke getoets deur die volgende drie biomerkers te gebruik: Die 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromied toets (MTT toets), wat mitochondriale aktiwiteit en sel lewensvatbaarheid meet; die enkel sel elektroforese toets (Komeettoets) wat DNS string breuke meet; die biosintese van metallotioniene (MT's) wat metaalvergiftiging verlaag. Erdwurms van die langtermyn blootstellingsubstraat asook eksemplare van bevolkings wat nie aan kadmium blootgestel was nie, is gebruik. Aanpassing is ondersoek deur gebruik te maak van allosiem polimorfisme, waar 7 ensiem koderende lokusse gebruik is asook van DNS polimorfisme deur neutrale genetiese merkers te selekteer. Die merkers wat gebruik is, was sitochroom c oksidase, subeenheid I (COI) en metallotionien-2 (mt-2) respektiwelik. Hierdie toetse is met dieselfde groepe bevolkings uitgevoer. 'n Bykomende van die studie aspek waar ook van DNS polimorfisme gebruik gemaak is, was daarop gemik om die spesie wat vir die huidige studie gebruik is, geneties te identifiseer en om vas te stel of die erdwurms aan die spesie Eisenia fetida of Eisenia andrei behoort. Die MT biosintese het nie die verwagte data gegenereer nie, hoofsaaklik weens die feit dat geskikte teenligaampies nie beskikbaar was nie (bespreek in Hoofstuk 5 afdeling 5.3.3). Soortgelyk, het die waardebepaling van DNS polimorfisme by die geselekteerde genetiese merker mt-2 nie genoegsame informasie verskaf om die potensiaal van die ontwikkeling van weerstand teen Cd in die langtermyn blootgestelde groep te verstaan nie. COI geenvolgordes van E. fetida en E. andrei wat op Genbank beskikbaar was, is gebruik om met die resultate van die huidige studie te vergelyk. Die spesie wat tydens die huidige studie gebruik is, is op hierdie wyse geïdentifiseer as E. andrei. Allosiem polimorfisme het geen vaste genetiese verskille tussen die langtermyn blootgestelde laboratoriumkulture en die ander bevolkings getoon nie. Al die bevolkings het verskil van die Hardy-Weinberg ewewigstoestand (χ2 > 5.9; p < 0.05) en het 'n lae heterosigositeit per lokus getoon (Ho ≤ 0.21), moontlik as gevolg van inteling. Sellewensvatbaarheid en proliferasie soos getoets met die MTT toets, het getoon dat selomosiete, geïsoleer vanuit die langtermyn Cd blootgestelde groep, die hoogste lewensvatbaarheid (98.42%) gehad het in vergelyking met die ander groepe (+/- 80%). Kruksal-Wallis ANOVA (H2, 225=109.7165 p < 0.001) het getoon dat die langtermyn Cd blootgestelde laboratoriumkultuur 'n beter respons vir akute blootstelling aan Cd gehad het. Hierdeur is gedemonstreer dat hierdie wurms 'n soort toleransie teenoor kadmium ontwikkel het. Soortgelyk het die komeettoets aangetoon dat daar in die langtermyn blootgestelde eksemplare minder DNS breuke voorgekom het na verdere blootstelling aan Cd as in die ander groepe. Van al die komeet parameters wat tydens die studie gemeet is (komeet stertlengte, Olive stert moment en stert DNS persentasie), het die stert DNS persentasie geblyk om die mees sensitiefste te wees, alhoewel al drie parameters aangetoon het dat die langtermyn Cd blootgestelde eksemplare meer weerstandbiedend was teen induksie van DNS enkelstring breuke weens Cd blootstelling (p < 0.001), as die wat nie voorheen blootgestel was nie. Die komeet en MTT toetse het aangetoon dat erdwurms met 'n voorgeskiedenis van Cd blootstelling 'n toenemende fiksheid teen hoër dososse van Cd ontwikkel het as die wat nie voorheen aan kadmium blootgestel was nie. My bevindings kon hoofsaaklik toon dat verskeie meganismes op die fisiologiese en biochemiese vlak 'n rol sou kon speel om Cd blootgestelde bevolkings by 'n chemies stresvolle omgewing te laat akklimeer. Duidelike ondersteuning vir die verskille tussen die getoetsde bevolkings deur van Cd geselekteerde merkers soos die mt-2 geen gebruik te maak om 'n meer finale afleiding te kan maak is nie verkry nie en behoort verder ondersoek te word.
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Chapman, Joshua A. "Soil microbial communities from the alimentary canal of the earthworm Lumbricus terrestris (Oligochaeta: lumbricidae)." Morgantown, W. Va. : [West Virginia University Libraries], 2006. https://eidr.wvu.edu/etd/documentdata.eTD?documentid=4756.
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Thesis (M.S.)--West Virginia University, 2006.Title from document title page. Document formatted into pages; contains viii, 75 p. : ill. (some col.), map. Includes abstract. Includes bibliographical references.
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Timmenga, Hubert J. "The transport of mineral and organic matter into the soil profile by Lumbricus rubellus Hoffmeister." Thesis, University of British Columbia, 1987. http://hdl.handle.net/2429/27551.
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The biology and ecology of the earthworm Lumbricus rubellus Hoffmeister, 1843, and its effects on the turn-over of organic matter and soil are not well known. To gather this information, the ingestion and egestion rates were measured using a litterbag technique and the transport of organic matter was quantified with a newly developed method, using soil columns to which ¹⁴C labelled plant material was added.
The feeding habits of the worm were positively influenced by temperature in wet soils (> -15m of water) and were negatively influenced in dry soil (< -15 m of water). The total egestion rate changed from 0.3 g.g⁻¹.day⁻¹ at 5 °C to 1.0 g.g⁻¹. day⁻¹ at 20° C in moist soil (- 5 m of water). The egestion rate at medium range temperatures, 10 and 15° C, was less affected by drought stress than at 5 and 20 °C. The egestion rate of carbon was a more stable parameter than the total egestion rate, and ranged from approximately 20 mg.g⁻¹.day⁻¹ at 5 °C, to 50 mg.g⁻¹.day⁻¹ at 20 °C.
The moisture and temperature effects were apparent in the Q₁₀ of the total egestion rate and of the egestion rate of carbon. The Q₁₀ ranged from 1.66 in wet soils to 3.27 in dry soils in the 5-15 °C interval and from 1.98 to 0.32 in the 10-20 °C range. For the egestion rate of carbon, the Q₁₀ ranged from 1.92 to 3.21 and from 1.28 to 0.47, respectively.
The body water content of the worm varied considerably with the soil water potential, and reached a maximum level of 5.5 kg.kg⁻¹ (dwt) between -15 metres of water and -30 metres of water. When under drought stress, worms stopped ingesting large quantities of soil, switched to a diet high in organic matter and lowered their activity.
In the ¹⁴C column experiment, the total cast production was significantly related to depth. L. rubellus produced 15 % of the cast on the surface of the soil, 46 % in the 0-5 cm layer, 22 % in the 5-10 cm layer and 16 % in the 10-15 cm layer.
Independent calculations from a) the uptake of ¹⁴C labelled carbon in earthworms, b) removal of litter from the surface and c) ¹⁴C label recovered from cast, showed that the worms ingested 78-82 % of the offered organic matter as shoot litter and 18-22 % as root litter. ¹⁴C originating from shoot and root litter was recovered in casts throughout the profile, indicating that the worms mixed food from all layers. The total egestion rate found in the column experiment was 5.2 times higher than was found in the litterbag technique under comparable conditions (2.34 vs 0.45 g.g⁻¹.day⁻¹). The egestion rate of carbon was similar in both techniques (37.1 vs. 46.1 mg.g⁻¹.day⁻¹, 10 °C). In preliminary litterbag trials, it was found that L. rubellus egested 15.5 mg.g⁻¹.day⁻¹ of carbon (5 °C) for each of four food types offered. The 5 °C temperature trial of the litterbag technique, showed a similar amount of carbon egested. It was concluded that the worm needed a constant amount of carbon to provide nutrients and energy, of which a part or all may originate from ingested microorganisms.
Based on the distribution of cast in the profile and the feeding strategies of L. rubellus, it was concluded that this earthworm cannot be classified as an epigeic worm. A new strategy class was proposed: eurygeic worms, earthworms living in the litter-soil interface, mixing organic matter into the profile and mineral soil into the litter layer.
Based on the literature and results from the present study, a computer model was developed to simulate the longterm effects of earthworms on an agricultural soil system. Simulations of the mixing of soil and organic matter in a limited-till agricultural system, showed that earthworms negatively affected the accumulation rate of surface litter and positively affected the organic matter content of the mineral soil. The model can be used to predict the trends in organic matter in soils, important in soil conservation, mine reclamation and reforestation.Land and Food Systems, Faculty of
Graduate
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Hariri, Abdolrahman Sadeghi. "Evaluation of immune responses and cytological changes in Lumbricus terrestris and Eisenia foetida as assays for xenobiotics." Thesis, University of North Texas, 1992. https://digital.library.unt.edu/ark:/67531/metadc798200/.
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The earthworms, Lubricus terrestris and Eisenia foetida, were used as non mammalian surrogate models to assess the immunotoxicpotential of xenobiotic to mammals. Assays were developed and optimized for detecting spreading activity and phagocytosis of rabbit red blood cell (RRBC), bacteria, and yeasts by macrophage-like coelomocytes of L. terrestris.
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Langdon, Caroline Juliet. "Relationships between lumbricid earthworms and arsenic-rich mine spoil wastes." Thesis, Lancaster University, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.274279.
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Khan, Farrukh Humayoon Rafique. "Studies on some of the effects of pesticides on earthworms." Thesis, Bangor University, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.263305.
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McArthur, F. K. "Histology, ultrastructure and immunocytochemistry of the neurosecretory systems of earthworms." Thesis, University of Newcastle Upon Tyne, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.378298.
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Whalen, Joann K. "Effects of earthworms on nitrogen flux and transformations in agroecosystems /." The Ohio State University, 1998. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487949508372199.
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Knorr, David B. "Influence of diet on biomass production of the earthworm Lumbricus terrestris in laboratory culture." Virtual Press, 1992. http://liblink.bsu.edu/uhtbin/catkey/845951.
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In a 28-day dietary study, Lumbricus terrestris were placed in one quart containers with soil and offered either corn (Zea mays L.), soybean (Glycine max L. Merr.) or alfalfa (Medicago sativa) leaves, corn leaves treated with a 1:1 solution of 28% N fertilizer and deionized water, corn or soybean stalks, or no addition. The worms were weighed initially and after 28 days to determine biomass production, which was used for determining food quality. Worms exhibited large weight gains when fed alfalfa or soybean leaves, intermediate weight gains when fed corn leaves treated with N, and little or no gains for the remainder of treatments. N content of the tissues was positively correlated to biomass production. These results support the hypothesis that earthworm growth is determined by food quality, particularly N content.Department of Natural Resources
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Sassani, Ramin. "Toxicity of Polychlorinated Biphenyls (Aroclor 1254) on the Earthworm Eisenia foetida." Thesis, University of North Texas, 1991. https://digital.library.unt.edu/ark:/67531/metadc500593/.
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Objectives were to: (1) assess toxicity of polychlorinated biphenyls on Eisenia foetida, in terms of survival (LC5O/LD5O), and suppression of coelomocytes to form secretory (SR) and erythrocyte rosettes (ER) with, and to phagocytize rabbit erythrocytes; and (2) compare results with those of Lumbricus terrestris to assess relative sensitivities to PCB. Using 5-d filter paper contact exposure protocol, LC50 and LD50 were 30.4 cg/cm2 and 4450 cg/g dry mass, respectively. Nominal PCB exposure concentrations of 5.0 and 10.0 pg/cm2 resulted in tissue levels of 1389 and 2895 pg/g dry mass causing a significant reduction in SR formation by 18 and 52%, respectively. ER formation and phagocytosis were reduced significantly (52 and 61%) only at the higher tissue concentration. Compared to reported data on lethality and immunomodulation in L. terrestris, E. foetida appears to be more resistant.
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Prieto, Roberto. "The role of earthworms in nitrous oxide emissions from forage agroecosystems." Thesis, McGill University, 2011. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=103783.
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Nitrous oxide (N2O) emission from agricultural soils contributes to the greenhouse effect, depletion of the ozone layer, and acid rain formation. In laboratory studies, soil in contact with earthworms had significantly higher N2O production than soil devoid of earthworm activity. The elevated N2O production occurs via activation or priming of nitrifying and/or denitrifying microorganisms. Yet, field scale experiments have been inconclusive with respect to N2O fluxes attributed to earthworms. The objectives of this thesis were in the field to (1) determine the effect of elevated anecic and endogeic earthworm populations on N2O fluxes from legume and non-legume enclosures, and in the laboratory to (2) qualify the denitrification community and (3) quantify the denitrification rate of earthworm-related structures including the gut, casts, burrows and middens of the anecic Lumbricus terrestris. In the field study, elevated earthworm populations increased N2O fluxes significantly (P<0.05) in legume but not in non-legume enclosures. Anecic species appeared to have a greater effect on N2O fluxes. The linear regression model of the flux data and number of earthworms added was significant (P<0.05); on average earthworms emitted 335 ng N2O m-2 h-1 from the legume enclosures when soil moisture exceeded 60% water-filled pore space. In the laboratory study, a 454 pyrosequencing analysis on the diversity and phylogeny of bacterial nosZ gene fragments (encoding N¬2O reductase) revealed a set of 39 unique OTUs, of which 14 were found only in the earthworm gut. The earthworm gut appears to have a unique set of endemic denitrifying bacteria. An acetylene block assay revealed that the earthworm itself had the greatest denitrification rate of 2.67 g N2O-N g soil-1 h-1, which was significantly (P<0.05) greater than bulk soil and other earthworm structures except fresh casts. Fresh casts had a denitrification rate of 0.94 g N2O-N g soil-1 h-1 which was significantly (P<0.05) greater than the rate of aged cast and bulk soil. The set of unique gut denitrifiers is highly active due to the favourable conditions in the gut, including anoxia and quality substrate. When fresh, anecic earthworm related structures are important "hot spots" favouring the activity of soil denitrifiers. This thesis demonstrates the importance of earthworm-denitrifier interactions for N2O emissions, particularly in legume-based agroecosystems, which should be considered when developing predictive models of greenhouse gas emissions from agricultural soils.Les émissions d'oxyde nitreux (N2O) provenant de sols agricoles contribuent à l'effet de serre, à la destruction de la couche d'ozone et à la formation de pluies acides. Des études en laboratoire ont démontré que, lorsque le sol est en contact avec des vers de terre, celui-ci présente des niveaux plus élevés de flux de N2O que lorsqu'il n'y a pas de verres de terre présents. Un taux élevé de N2O se produit lorsque les micro-organismes nitrifiants et/ou dénitrifiants sont activés. Pourtant, les études publiées sur les essais aux champs n'ont pas été concluantes quant aux niveaux de N2O attribuables à la présence de vers de terre. Les objectifs de ce mémoire étaient : (1) sur le terrain, de déterminer l'incidence des quantités élevées de vers de terre anéciques et endogés sur les niveaux de flux de N2O dans les chambres avec et sans légumineuses, (2) en laboratoire, de définir les agents bactériologiques dénitrificateurs, et (3) de quantifier le taux de dénitrification des structures associées aux vers de terre, incluant intestins, turriculés, tubes et tertres du ver de terre anécique Lumbricus terrestris. Selon les études effectuées sur le terrain, lorsqu'il y avait une présence accrue de vers de terre, les niveaux de N2O augmentaient de façon importante (P<0,05), mais seulement dans les chambres avec des légumineuses. Les espèces anéciques semblaient avoir un effet plus important sur les émissions de N2O. Le modèle de régression linéaire des données relatives aux niveaux de N2O et à la quantité de vers de terres ajoutés était significative (P<0,05) ; en moyenne, les vers de terre émettaient 335 ng N2O m-2 h-1 lorsque l'humidité du sol dans les chambres avec légumineuses excédait 60% de l'espace poral irrigué. Lors de l'étude en laboratoire, une analyse de 454 pyroséquençage portant sur la diversité et la phylogénie des fragments génétiques de la bactérie nosZ (codification de réductase de N2O) a révélé un ensemble de 39 unités taxonomique opérationel (UTOs) unique, dont 14 identifiées dans les intestins du ver de terre. Les intestins semblent contenir un ensemble unique de bactéries dénitrificatrices endémiques. Une analyse au blocage à l'acétylène a démontré que le ver de terre lui-même présentait le potentiel le plus élevé de dénitrification, soit 2,67 µg N2O-N g sol-1 h-1, valeur nettement supérieure (P<0,05) à celles du sol brut et des autres structures de vers de terre, à l'exception des turriculés frais. Les turriculés frais indiquaient un taux moyen de dénitrification de 0,94 µg N2O-N g sol-1 h-1, donc plus élevé (P<0,05) que le taux de turriculés vieillis et du sol brut. L'ensemble distinct de dénitrificateurs intestinaux est très actif de par leurs conditions favorables dans les intestins, dont l'anoxie et le substrat de qualité. Lorsque les structures de vers de terre anéciques sont fraîches, celles-ci deviennent des endroits propices favorisant la dénitrification du sol. Ce mémoire affirme l'importance de l'interaction entre les verres de terre et les microorganismes dénitrifiants quant aux émissions de N2O, en particulier dans les agroécosystèmes de légumineuses. Ces interactions devraient être prises en compte lors du développement de modèles de prévision des émissions de gaz à effet de serre provenant des sols agricoles.
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Moody, Sandra Ann. "Aspects of dispersal of wheat staw fungi by earthworms and springtails." Thesis, Lancaster University, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.333533.
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Clasper, Paula Jeanette. "The effects of paper mill sludge on earthworms and soil microorganisms." Thesis, Lancaster University, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.429963.
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Spring, Christian Alexander. "The effects of earthworms on soil structure in an upland grassland." Thesis, University of Stirling, 2003. http://hdl.handle.net/1893/3538.
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As Charles Darwin first noted in 1881, earthworms through their burrowing and casting activities, play an important role in the creation and maintenance of soil structure. Burrowing activity leads to the reorganisation of voids and creation of macropores within the soil. This has implications for aeration and the flow properties of water through soils. Casting activity affects the structural stability of soil through the stabilisation of aggregates. The overall aim of this research project has been to investigate the effects of earthworm activity and diversity on void space and aggregation in an upland soil. This research has been carried out as part of NERC's Thematic Programme on Soil Biodiversity. The field site was located on the Macaulay Land Use Research Institute's experimental farm at Sourhope in the Scottish Borders. Three experiments were designed to investigate the impact of earthworms on soil fabric, with each experiment representing an increased level of system complexity. The simplest experiment took place in a controlled environment and used an artificial soil and different earthworm treatments. The second level of system complexity used soil from Sourhope which had its structure removed, and then earthworm and liming treatments applied. The most complex experiment also used Sourhope soil and liming and earthworm treatments, except in this case the soil was undisturbed. The effects of earthworms and liming on void space were characterised using saturated hydraulic conductivity to measure macroporosity, and image analysis to quantify total porosity and void size distribution. Aggregation was assessed through aggregate stability and point counts of earthworm excremental features. The effect of earthworm inoculation in the simplest experiment led to the reorganisation of voids through increased abundance of voids > 2 mm2 in area, and decreases in the proportion of voids with an area < 2 mm2. No significant effects were observed on aggregate stability. The effect of liming in the experiment using disturbed soil was to increased abundance of voids > 2 mm2. No significant effects were observed on aggregation due to either liming or earthworm inoculation. In the most complex experiment, neither liming nor earthworm inoculation led to changes in void space or aggregation, except for an increase in saturated hydraulic conductivity and therefore macroporosity due to earthworm inoculation. The overall conclusions from this research were that as system complexity increased, then the effects of the treatments on void space and aggregation became more difficult to isolate. Nevertheless, it was clear that liming significantly affected void space through increased abundance of earthworms. Out of the two treatments applied to the Sourhope soil, liming had the strongest effect on both earthworm abundance and void space.
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Braga, Lucas Palma Perez. "Disentangling the influence of earthworms on microbial communities in sugarcane rhizosphere." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/64/64133/tde-26052017-100757/.
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For the last 150 years many studies have shown the importance of earthworms for plant growth, but the exact mechanisms involved in the process are still poorly understood. Many important functions required for plant growth can be performed by soil microbes in the rhizosphere. To investigate earthworm influence on the rhizosphere microbial community, it was performed a macrocosm experiment with and without Pontoscolex corethrurus (EW+ and EW-, respectively) and followed various soil and rhizosphere processes for 217 days with sugarcane. In the second chapter of this thesis it was demonstrate that in EW+ treatments, N2O concentrations belowground (15 cm depth) and relative abundances of nitrous oxide genes (nosZ) were higher in bulk soil and rhizosphere, suggesting that soil microbes were able to consume earthworm-induced N2O. Shotgun sequencing (total DNA) revealed that around 70 microbial functions in bulk soil and rhizosphere differed between EW+ and EW- treatments. Overall, genes indicative of biosynthetic pathways and cell proliferation processes were enriched in EW+ treatments, suggesting a positive influence of worms. In EW+ rhizosphere, functions associated with plant-microbe symbiosis were enriched relative to EW- rhizosphere. Ecological networks inferred from the datasets revealed decreased niche diversification and increased keystone functions as an earthworm-derived effect. Plant biomass was improved in EW+ and worm population proliferated. Considering that earthworms contributed to with extra resources, it was evaluated in chapter three response of the soil resistome of sugarcane macrocosms under the influence of earthworms. Mechanisms of resistance against antimicrobial compounds appear to be an obligatory feature for the ecology and evolution of prokaryotic forms of life. However, most studies on resistance dynamics have been conducted in artificial conditions of anthropogenic inputs of antibiotics into very specific communities such as animal microbiomes. To resolve why and how resistance evolves, it is important to track antibiotics resistance genes (ARGs) (i.e., the resistome) in their natural hosts and understand their ecophysiological role in the environment. The results demonstrated that earthworms influenced changes of ARGs in bulk soil and rhizosphere. Negative correlations between ARGs and taxonomical changes were increased in EW+. Differential betweenness centrality (DBC=nBCEW+ - nBCEW-) values comparing the network models with and without earthworms showed earthworm presence changed the composition and the importance of the keystone members from the models. Redundancy analysis suggested that ARGs may be associated with microbial fitness, as the variance of relative abundance of members of the group Rhizobiales could be significantly explained by the variance of a specific gene responsible for one mechanism of tetracycline detoxificationAo longo dos últimos 150 anos muitos estudos têm demonstrado a importância das minhocas para o crescimento de plantas. Porém o exato mecanismo envolvido neste processo ainda é muito pouco compreendido. Muitas funções importantes necessárias para o crescimento de plantas podem ser realizadas pela comunidade microbiana da rizosfera. Para investigar a influência das minhocas na comunidade microbiana da rizosfera, foi desenvolvido um experimento de macrocosmo com cana-de-açúcar com e sem Pontoscolex corethrurus (EW+ e EW-, respectivamente) seguindo diversos procedimentos por 217 dias. No Segundo capítulo da tese é demonstrado que no tratamento EW+, as concentrações de N2O dentro do solo (15 cm profundidade) e a abundância relativa dos genes óxido nitroso redutase (nosZ) foram elevadas no solo e na rizosfera, sugerindo que microrganismos do solo foram capazes de consumir a emissão de N2O induzida pelas minhocas. O sequenciamento do DNA total revelou que aproximadamente 70 funções microbianas no solo e na rizosfera apresentaram diferenças entre os tratamentos EW+ e EW-. No geral, genes associados a biossíntese e proliferação de células foram enriquecidos em EW+, sugerindo uma influencia positiva por parte das minhocas. Na rizosfera EW+, funções associadas a simbiose entre planta e microrganismos foram relativamente enriquecidas comparado com rizosfera EW-. Modelos de rede de interação ecológica revelam menor número de diversificação de nichos e aumento de funções importantes como um efeito derivado da influência das minhocas. A biomassa das plantas foi aumentada no tratamento EW+ e a população de minhocas proliferou. Considerando que as minhocas contribuíram com o aumento de nutrientes, foi avaliado no capítulo três a resposta do resistoma presente nas comunidades microbianas dos solos do experimento. Mecanismos de resistência contra compostos antimicrobianos parecem ser características obrigatórias para a ecologia e evolução de procariotos. Entretanto, a maior parte dos estudos sobre genes de resistência tem sido conduzida em condições artificiais utilizando fontes antropogênicas de antibióticos em comunidades microbianas muito específicas como por exemplo o microbioma animal. Para resolver por que e como a resistência evolui, é importante estudar genes de resistência a antibióticos (GRA) (i.e., resistoma) no seu ambiente natural e entender seu papel ecofisiologico no ambiente. Os resultados demonstraram que minhocas influenciaram a mudança na composição de GRA no solo e na rizosfera. Tratamentos EW+ apresentaram maior número de correlações negativas entre ARG e grupos taxonômicos. A medida de centralidade diferencial (DBC=nBCEW+ - nBCEW-) comparando os modelos de rede de interações obtidos mostrou que a composição e o nível de importância dos indivíduos mais influentes é alterado nos tratamentos EW+ comparado com EW-. Além disso, por meio de uma análise de redundância (RDA) foi demonstrado que as alterações na abundancia relativa de GRA podem ser explicadas pelas alterações verificadas em grupos taxonômicos
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Giai, Carla. "Fire, Exotic Earthworms and Plant Litter Decomposition in the Landscape Context." The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1236626931.
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Wan, Hon Chi Judy. "Interaction of earthworms and microorganisms on nutrient availability and crop growth." HKBU Institutional Repository, 2004. http://repository.hkbu.edu.hk/etd_ra/588.
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McDonald, Jennifer C. Venables Barney J. "Bacterial challenge in Lumbricus terrestris a terrestrial invertebrate immunotoxicity model /." [Denton, Tex.] : University of North Texas, 2007. http://digital.library.unt.edu/permalink/meta-dc-3640.
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Dempsey, Mark A. "Exotic earthworms and soil microbial community composition in a northern hardwood forest." Miami University / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=miami1259958575.
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Dempsey, Mark Austin. "Exotic earthworms and soil microbial community composition in a northern hardwood forest." Oxford, Ohio : Miami University, 2009. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=miami1259958575.
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Herring, Reese. "Modulation of the Coelomic Fluid Protein Profile in the Earthworm, Lumbricus Terrestris, After Exposure to Copper as Copper Sulfate." Thesis, University of North Texas, 2010. https://digital.library.unt.edu/ark:/67531/metadc28428/.
Full textAbstract:
Proteomic techniques were used to analyze the protein profile of earthworm, Lumbricus terrestris, coelomic fluid collected by either whole body dissection method or the coelomic cavity puncture method. Data demonstrated that collection of coelomic fluid using the coelomic cavity puncture method protocol resulted in a 32% reduction, 377 +/- 4.5 vs 253+/- 19.9 (p=0.0007), in the number of individual proteins. It was determined that the coelomic cavity puncture method yielded a "cleaner" preparation, one less contaminated with extraneous proteins from intestinal tissue, gut contents, and body wall materials. This protocol was used in all later studies. The same proteomic techniques were used to evaluate the effects that exposure to Cu (1.0 μg/cm2) as CuSO4 had on the earthworm coelomic fluid profile. Comparison of protein profile from exposed earthworms demonstrated a significant reduction in the number of proteins expressed (184 ± 2.64 vs 253 ±19.9 p=0.0192) when compared to control organisms. Cu exposure also resulted in a modulation of the protein profile with treated earthworms expressing 47 new proteins that were not identified in unexposed worm coelomic fluid. Additionally, 116 proteins found in coelomic fluid collected from normal worms were absent in Cu exposed organisms. Finally, 137 proteins were conserved or found in both control and exposed organisms; however of these proteins, 24 were up-regulated, 105 were down-regulated, and 8 were unchanged as a result of Cu exposure.
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Rodriguez, Grau Jorge Luis. "Suppression of Immune Functions by PCBs in the Earthworm Lumbricus terrestris." Thesis, University of North Texas, 1989. https://digital.library.unt.edu/ark:/67531/metadc798391/.
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This research is part of an effort to develop non-mammalian surrogate immunoessays with the earth worm Lumbricus terrestris to assess immunotoxic potential of xenobiotics to mammals. The objective was to determine if earthworm immunoessays, namely E- and S- rosette formation and phagocytosis, are sensitive to a known mammalian immunotoxin, the PCB Arclor 1254. Results are presented in terms of PCB exposure and tissue concentrations during uptake/depuration.
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Eyambe, George Sona. "Cellular Biomarkers for Measuring Toxicity of Xenobiotics: Effects of PCBs on Earthworm Lumbricus Terrestris Coelomocytes." Thesis, University of North Texas, 1991. https://digital.library.unt.edu/ark:/67531/metadc332716/.
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The research presented herein provides information on coelomocyte (leukocyte) collection, function and immunotoxicity from polychlorinated biphenyls (PCB) in the earthworm Lumbricus terrestris. Research was undertaken as part of an overall goal to develop a well-documented and scientifically valid non-mammalian surrogate immunoassay with the earthworm Lumbricus terrestris to assess immunotoxic potential of xenobiotics. The principal objectives were to: (1) Develop an extrusion model for analyzing immunotoxicity of xenobiotics; (2) determine if coelomocytes can be collected repeatedly without obvious harm to the earthworm or change in immune response of the coelomocytes harvested and (3) validate the response sensitivity profiles of a panel of biomarkers {differential and total cell counts, erythrocyte rosette (ER) and secretory rosette (SR) formation with, and phagocytosis of antigenic rabbit red blood cells} in earthworms after acute exposure to a known mammalian and L. terrestris immunotoxin, the PCB Aroclor 1254.
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Horswell, Jacqueline. "Investigation of approaches to accelerate atrazine mineralisation in soil." Thesis, University of Aberdeen, 1997. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU094707.
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Atrazine, a member of the s-triazine herbicides, appears on the EC Red List of chemicals that cause environmental concern, with residues occurring frequently in sub-soils and aquifers world-wide. Microbial metabolism is considered to be the major mechanism of complete removal of atrazine from the soil environment. Laboratory-based studies were carried out to investigate the microbial mineralisation of atrazine in soil, and to develop novel methods for potential acceleration of breakdown. In initial investigations, simple microcosm experiments were carried out to identify the importance of different fractions (water-soluble and water-insoluble) of plant residues to the dynamics, and extent of atrazine mineralisation. The amendment of soil with different plant residue fractions initially inhibited (for the water-soluble fraction) or enhanced (for the water-insoluble fraction) dynamics of atrazine mineralisation. However, by the end of the incubation, there was no overall effect on atrazine mineralisation. This suggested that increasing the soil organic matter content may render the herbicide less bioavailable to the degrader population. Investigations carried out to determine which component of the microbial biomass was more important in atrazine mineralisation showed that substantial removal of the fungal and Gram-negative bacterial population inhibited atrazine mineralisation in the soil. Experiments to selectively enrich the soil for fungal or bacterial atrazine degraders isolated a mixed bacterial culture able to accelerate atrazine mineralisation when inoculated into soil. The effect of the presence of the earthworm Lumbricus terrestris on the indigenous atrazine degrading microflora was investigated. Results indicated that atrazine mineralisation could be accelerated, but this was not primarily due to increases in microbial biomass, but possibly due to physio-chemical changes brought about by the earthworm and subsequent alterations in atrazine bioavailability.
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Carpenter, Daniel. "The role of earthworms in the chemical and physical weathering of soil minerals." Thesis, University of Reading, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.496963.
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Minerals are an important component of the soil environment. They provide a structural framework which supports plants and contributes to the physical heterogeneity of soil. They contribute to the fertility of soils in providing a source of essential nutrients through mineral weathering and they regulate the availability of nutrients in soil through their exchange capacity. Some minerals also affect the moisture content of soils through their ability to absorb water. Earthworms are one of the most important soil organisms, particularly in temperate ecosystems, because of the role they have in regulating many processes in soils. The interaction between these two critical components of soil ecosystems has not been extensively studied. This potentially important interaction is the subject of this thesis. The effect of three earthworms (Eisenia veneta, Allolobophora chlorotica and Lumbricus terrestris) on five minerals (olivine, anorthite, biotite, smectite, illite and kaolinite) was investigated in a series of laboratory experiments using the following techniques: X-ray diffraction, Scanning Electron Microscopy, Fourier Transform Infrared Spectroscopy and chemical methods.
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Schermaier, Anton Francis. "INFLUENCE OF EARTHWORMS ON PLANT AND SOIL INVERTEBRATE COMMUNITIES OF THE CLEVELAND METROPARKS." Cleveland State University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=csu1367843264.
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Zelles, Alexandra M. "Examining the relationship between garlic mustard (Alliaria petiolata) and European earthworms." Wright State University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=wright1348589345.
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Cardozo-Tacaná, José. "Impact of six cropping sequences on soybean cyst nematode, soil arthropods, and earthworms /." free to MU campus, to others for purchase, 1996. http://wwwlib.umi.com/cr/mo/fullcit?p9809665.
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Leland, Jarrod Ethan. "Evaluating the Hazard of Land Applying Composted Diazinon Waste Using Earthworm Biomonitoring." Thesis, Virginia Tech, 1998. http://hdl.handle.net/10919/10079.
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A process for disposing of pesticide rinsewater generated from the rinsing of application equipment is being developed at Virginia Polytechnic Institute and State University. This process involves the sorption of pesticides onto an organic matrix followed by degradation in a composting environment. We are now evaluating the hazards that might be associated with land-applying composted pesticide waste. Diazinon was the first pesticide selected for evaluation, which consisted of two studies. The first used the earthworm species Eisenia foetida to evaluate the toxicity of soil amended with composted diazinon waste. The second study determined the bioavailability of delta-2-14C-diazinon and its degradation products to E. foetida in soil amended with composted delta-2-14C-diazinon.
Results from the first study indicate that uncomposted diazinon sorbent and 30-day composted diazinon sorbent were toxic to E. foetida at sublethal and lethal levels. However, E. foetida exposed 60-day composted diazinon sorbent did not experience mortality or demostrate sublethal effects commonly associated with acetylcholinesterase inhibition.
Earthworms exposed to diazinon that was uncomposted or composted for 30 days in the radiolabelled study experienced higher mortality than in the field study. After 30 and 60 days of composting 14C-diazinon became unextractably incorporated into organic matter and very little was mineralized. Earthworms were shown to accumulate radioactivity when exposed to soil amended with 60- day composted delta-2-14C-diazinon. The majority of this radioactivity was unextractably bound to earthworm tissue and that which was extractable contained only trace levels of delta-2-14C-diazinon. Based on the absence of toxicity in the field study and the low levels of 14C-diazinon present in earthworm tissues, 60 days of composting appears to greatly reduce the hazard that diazinon rinsate poses to E. foetida.Master of Science
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Dalby, Paul Reginald. "Competition between earthworms in high rainfall pastures in the Mt. Lofty Ranges, South Australia." Title page, contents and summary only, 1996. http://web4.library.adelaide.edu.au/theses/09PH/09phd137.pdf.
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Copy of author's previously published work inserted. Bibliography: leaves 261-306. The objectives of the project were: i. to determine whether there are competitive interactions between Aporrectodea trapezoides and A. caliginosa and A. rosea.--ii. to investigate compeditive interactions between A. calignosa, Microscolex dubius and A. trapezoides.--iii . to determine the likely impact of A. longa on soil fauna, especially the native earthworm, Gemascolex lateralis, in native ecosystems.
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Pham, Quang. "Relationships between functional traits, bioturbation and water transfers of earthworms sampled in northern Vietnam." Electronic Thesis or Diss., Sorbonne université, 2023. https://accesdistant.sorbonne-universite.fr/login?url=https://theses-intra.sorbonne-universite.fr/2023SORUS606.pdf.
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Les vers de terre, de par la production de turricules et de galeries jouent un rôle majeur dans la formation et l'entretien de la structure du sol avec des conséquences sur les transferts d'eau. Cependant, la majeure partie de nos connaissances concerne la famille des Lumbricidae, tandis que la famille la plus diversifiée, les Megascolecidae, est largement sous-étudiée. Par conséquent, cette thèse visait à mieux comprendre l'impact des vers de terre tropicaux de la famille des Megascolecidae sur la structure du sol et les transferts d'eau, en particulier en utilisant leurs traits morpho-anatomiques comme proxy.Pour ce faire, deux expériences ont été menées en laboratoire. Dans la première, 23 espèces de vers de terre ont été échantillonnées dans le nord du Vietnam et leurs traits morpho-anatomiques ont été mesurés. Les vers de terre ont été classés en quatre catégories écologiques en fonction de leur traits morpho-anatomiques. Les vers de terre ont ensuite été incubés dans des mésocosmes afin d'y mesurer le volume et la compaction de leur drilosphere ainsi que l'infiltration de l'eau. Dans la deuxième expérience, l'effet individuel et interactif du ver anécique Amynthas zenkevichi et du ver endogé Pontoscolex corethrurus sur la structure du sol et les transferts d'eau ont été mesurés. Les réseaux de galerie ont été caractérisés à l'aide de la tomographie aux rayons X et les transferts d'eau ont été caractérisés en termes d'infiltration d'eau, d'évaporation et d'humidité du sol.Les résultats de la première expérience ont montré (i) une bonne correspondance entre le volume des différentes parties du drilopshere et les quatre catégories écologiques, alors que les différences étaient moins nettes pour la compaction des turricules ou la compaction autour des galeries ; ii) les vers de terre avaient soit un effet positif ou neutre sur l'infiltration de l'eau du sol sans distinction nette entre les quatre catégories écologiques ; (iii) l'utilisation possible des traits morpho-anatomiques pour prédire l'impact des vers de terre sur l'infiltration de l'eau du sol et la compaction de la drilopshere. Les résultats de la deuxième expérience ont montré que la présence des espèces A. zenkevichi et P. corethrurus ensemble avait un léger effet synergique positif sur la résistance du sol à la perte d'eau par évaporation.Pour conclure, ce travail montre que les vers de terre tropicaux peuvent être classés en catégories écologiques, mais que les liens avec le fonctionnement du sol ne sont pas toujours cohérents. Cette thèse met en évidence de nouvelles pistes de recherche basées sur les traits d'effet, qui peuvent être utilisées pour identifier les effets des vers de terre tropicaux sur la structure du sol et l'infiltration de l'eauEarthworms are known to play a major role in soil structure formation and maintenance through the production of casts and burrows with consequences on soil water transfers. However, most of the literature is based on Lumbricidae species, while the most diverse family, the Megascolecidae, is comparatively understudied Therefore, this thesis aimed at providing a better understanding of the impact of tropical earthworms from the Megascolecidae family on soil structure and water transfers, particularly using their morpho-anatomical traits as a proxy.To do so, two experiments were conducted in laboratory conditions. In the first, 23 earthworm species were sampled in northern Vietnam and their morpho-anatomical traits were measured. Earthworms were assigned into four ecological categories based on the morpho-anatomical traits selected by Bottinelli et al. (2020) for Lumbricidae species. Earthworms were incubated in mesocosms and the whole drilosphere (i.e., volume of surface and belowground casts, empty burrows and lateral soil compaction and bulk density of casts and the lateral compaction) was characterized by X-ray computed tomography. In addition, the soil water infiltration was measured. In the second experiment, the individual and interactive effect of the anecic Amynthas zenkevichi and the endogeic Pontoscolex corethrurus on soil structure and resultant effects on water transfers were investigated. Burrow systems were characterized using X-ray tomography and soil water transfers were characterized in terms of water infiltration, evaporation, and moisture.Results of the first experiment showed (i) a good match between the volume of the different parts of the drilopshere and the four ecological categories, whereas differences were less clear for the bulk density of casts or at the vicinity of burrows; (ii) earthworms had no or a positive effect on soil water infiltration without clear distinction between the four ecological categories; (iii) the possible use of both morpho-anatomical traits and machine learning to predict the impact of earthworms on soil water infiltration and bulk density variations of the drilosphere. Results of the second experiments showed that the presence of A. zenkevichi and P. corethrurus species together had a slight, synergistic, positive effect on soil resistance to water loss by evaporation.To conclude, this thesis showed that tropical earthworms can be assigned into ecological categories, but links with soil functioning can somehow be wrong. This thesis highlights new avenues of research based on effect traits, that can be used to identify the effects of tropical earthworms on soil structure and water infiltration
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Farenhorst, Annemieke. "Influence of earthworms (Lumbricus terrestris L.) on the dissipation and distribution of herbicides in soil." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp02/NQ35154.pdf.
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