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Tesis sobre el tema "Cadmium effects on SOD1"

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Publicado: 10 de marzo de 2023

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1

BOVIO, FEDERICA. "The cadmium altered oxidative homeostasis leads to energetic metabolism rearrangement, Nrf2 activation with increased GSH production and reduced SOD1 activity in neural cells". Doctoral thesis, Università degli Studi di Milano-Bicocca, 2021. http://hdl.handle.net/10281/309982.

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Il cadmio, elemento chimico ampiamente usato in ambito industriale, è considerato un contaminante ambientale con effetti tossici sugli organismi viventi. Il suo ingresso nel corpo umano può avvenire per inalazione o ingestione di cibi ed acqua contaminati, fumo di sigaretta o impiego professionale, con tratto respiratorio e gastrointestinale principalmente coinvolti nel suo assorbimento cellulare. Anche il cervello è un bersaglio della tossicità del cadmio, che può entrare nel sistema nervoso centrale tramite una maggiore permeabilità della barriera ematoencefalica o attraverso i nervi olfattivi. Infatti, l'esposizione al cadmio è stata correlata sia ad alterazioni funzionali del sistema nervoso sia a malattie neurodegenerative, come la sclerosi laterale amiotrofica (SLA). Il 90-95% dei casi di SLA sono sporadici (sALS), mentre il restante 5-10% ha origine familiare (fALS), di cui il 15-20% è attribuito a mutazioni nel gene dell’enzima antiossidante superossido dismutasi 1 (SOD1). SOD1 è un omodimero di 32 kDa, in cui ciascun monomero presenta un ponte disulfuro e due ioni metallici, il rame con ruolo catalitico e lo zinco con funzione strutturale. Poiché uno dei principali meccanismi con cui il cadmio esercita la propria tossicità è lo stress ossidativo, responsabile di un insieme di eventi avversi che culminano nella morte cellulare, scopo di questa tesi è lo studio dell'effetto neurotossico del cadmio sul metabolismo energetico nella linea cellulare umana SH-SY5Y, sulle difese antiossidanti in cellule LUHMES differenziate e sulla funzione di SOD1 in tre modelli sperimentali (proteina ricombinante in E. coli, linea cellulare SH-SY5Y e nematode Caenorhabditis elegans). La valutazione del metabolismo energetico in cellule SH-SY5Y trattate per 24 ore con dosi sub-letali di CdCl2 ha evidenziato il passaggio ad un metabolismo anaerobico; infatti cellule trattate mostrano un aumento della glicolisi, una maggiore produzione di ATP per via glicolitica e una ridotta funzionalità mitocondriale rispetto al controllo. L’apporto bioenergetico in presenza di cadmio non altera la dipendenza da glucosio, ma aumenta quella da glutammina riducendo l’apporto derivato dagli acidi grassi. Inoltre, si osserva un aumento del GSH totale, del rapporto GSSG/GSH e della perossidazione lipidica, tutti indici di un'alterata omeostasi ossidativa. Quest’ultima è stata investigata in cellule LUHMES differenziate, in cui 24 ore di esposizione al cadmio hanno determinato, alle dosi più basse, un aumento del livello di GSH totale e un’attivazione di Nrf2 mediata da p21 e P-Akt. Gli effetti negativi del cadmio sulla vitalità cellulare possono essere annullati dall'aggiunta di GSH e dal trattamento in conditioned medium (CM) ottenuto da astrociti o microglia. Nelle LUHMES trattate in CM il livello totale di GSH rimane paragonabile a quello delle cellule non trattate anche alle concentrazioni più elevate di CdCl2. Infine, l’effetto del cadmio, combinato a dosi fisse di rame e/o zinco, sull'attività catalitica della proteina ricombinante GST-SOD1, espressa in E. coli BL21, ha mostrato una riduzione dose-dipendente dell'attività di SOD1 solo in presenza di rame, mentre il livello di espressione proteica rimane sempre costante. Risultati analoghi sono stati ottenuti nella linea cellulare SH-SY5Y, in cui l'attività enzimatica di SOD1 è diminuita in modo sia dose che tempo-dipendente dopo il trattamento con cadmio per 24 e 48 ore, così come nel nematode C. elegans, in cui si osserva una riduzione del 25% nell’attività di SOD1 dopo 16 ore di trattamento con cadmio. In entrambi i casi il livello di espressione proteica dell’enzima rimane invariato. In conclusione, il cadmio ha determinato il passaggio ad un metabolismo più anaerobico, l'attivazione di Nrf2, con conseguente aumento nella produzione di GSH e una riduzione dell'attività di SOD1.
The heavy metal cadmium is a widespread toxic pollutant, released into the environment mainly by anthropogenic activities. Human exposure can occur through different sources: occupationally or environmentally, with its uptake through inhalation of polluted air, cigarette smoking or ingestion of contaminated food and water. It mainly enters the human body through the respiratory and the gastrointestinal tract and it accumulates in liver and kidneys. Brain is also a target of cadmium toxicity, since this toxicant may enter the central nervous system by increasing blood brain barrier permeability or through the olfactory nerves. In fact, cadmium exposure has been related to impaired functions of the nervous system and to neurodegenerative diseases, like amyotrophic lateral sclerosis (ALS). ALS is a fatal motor neuron pathology with the 90-95% of ALS cases being sporadic (sALS), while the remaining 5-10% of familial onset (fALS); among fALS, the 15-20% is attributed to mutations in superoxide dismutase 1 (SOD1). SOD1 is an antioxidant protein responsible for superoxide anions disruption and it is a homodimeric metalloenzyme of 32 kDa mainly located in the cytoplasm, with each monomer binding one catalytic copper ion and one structural zinc ion within a disulfide bonded conformer. Since oxidative stress is one of the major mechanisms of cadmium induced toxicity and an alteration of oxidative homeostasis, through depletion of antioxidant defences, is responsible for a plethora of adverse outcoming mainly leading to cell death; we focused on cadmium effect (1) on the energetic metabolism in human neuroblastoma SH-SY5Y cell line, (2) on the oxidative defences responses in differentiated human LUHMES neural cell line and (3) on the function of human SOD1 in a three models approach (recombinant protein in E. coli, in SH-SY5Y cell line and in the nematode Caenorhabditis elegans). The evaluation of energetic metabolism of SH-SY5Y neural cells treated with sub-lethal CdCl2 doses for 24 hours, showed an increase in glycolysis compared to control. This shift to anaerobic metabolism has been confirmed by both glycolytic parameters and greater ATP production from glycolysis than oxidative phosphorylation, index of less mitochondrial functionality in cadmium treated cells. Regarding the fuel oxidation cadmium caused an increase in glutamine dependency and a specular reduction in the fatty acids one, without altering the glucose dependency. Moreover, we observed an increase in total GSH, in the GSSG/GSH ratio and in lipid peroxidation, all index of an altered oxidative homeostasis better investigated in LUHMES cells. In this model a 24h cadmium administration enhanced the total GSH content at the lower doses, at which also activates Nrf2 through a better protein stabilization via p21 and P-Akt. The metal adverse effects on cell viability can be rescued by GSH addition and by cadmium treatment in astrocytes- or microglia-conditioned medium. In the latter cases the total GSH level remains comparable to untreated cells even at higher CdCl2 concentrations. Finally, SOD1 catalytical activity has been investigated in the presence of cadmium. The first evaluation of this metal combined with fixed copper and/or zinc on the recombinant GST-SOD1, expressed in E. coli BL21, showed a dose-dependent reduction in SOD1 activity only when copper is added to cellular medium, while the expression remains always constant. Similar results were obtained in SH-SY5Y cell line, in which SOD1 enzymatic activity decreased in a dose- and time-dependent way after cadmium treatment for 24 and 48 hours, without altering its expression; as well as in the Caenorhabditis elegans model, where a 16 hours cadmium treatment caused a 25% reduction only in SOD1 activity. In conclusion, cadmium caused a shift to anaerobiosis, a Nrf2 activation, with increased GSH production, and a reduction in SOD1 activity.
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Jinadasa, K. B. P. Neelantha. "Cadmium effects on vegetables : production, physiology and biochemistry /". View thesis View thesis, 1998. http://library.uws.edu.au/adt-NUWS/public/adt-NUWS20030520.085431/index.html.

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Santos, José António da Costa. "Cadmium effects in Nitzschia Palea frustule proteins". Master's thesis, Universidade de Aveiro, 2010. http://hdl.handle.net/10773/8816.

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Mestrado em Toxicologia e Ecotoxicologia
As diatomáceas são organismos eucarióticos fotossintéticos, cuja relevância como espécies bioindicadoras foi há muito estabelecida, por via de índices ecológicos, ou por via de testes de toxicidade baseados em características ecológicas. A parede celular silicificada (frustula) é a característica mais distintiva destes organismos, permitindo uma identificação da espécie, e fornecendo a indicação de stresses ambientais, devido à indução de formações anormais da frústula. Estas teratologias são a consequência de perturbações no processo de biosilicificação, e podem ocorrer em culturas laboratoriais, ou devido a contaminação por metais, ou pesticidas. De entre os indutores de teratologias, os metais, como o cádmio, são a classe mais relevante devido à sua ocorrência natural ou antropogénica na natureza, e pela sua alta toxicidade relativa às pequenas quantidades presentes. Embora o processo de formação da frustula não esteja ainda completamente esclarecido, nos últimos anos tem sido publicada informação que revela a existência de proteínas na frústula, algumas delas contribuindo para a biosilicificação. O estudo das alterações induzidas pelo cádmio na quantidade, variedade, e relação das proteínas presentes na frústula, foram os objectivos deste trabalho, juntamente com a quantificação de cádmio nas fracções da frústula. Os resultados deste trabalho mostraram que a exposição ao cádmio aumentou o conteúdo proteico da frústula. Cerca de 80% dos peptideos aumentou a expressão na presença de Cd. Este foi sobretudo retido extracelularmente, encontrando-se 85% do Cd ligado a frustulinas. O presente trabalho demonstrou que as frustulinas são extremamente importantes para a defesa da célula dos efeitos do cádmio, contribuindo com dois novos supostos mecanismos de tolerância ao cádmio: o de reforço da frústula, e a protecção celular contra a entrada de Cd, através da quelação extracelular dos iões metálicos. Estes resultados mostram que as frustulinas podem ter um papel importante na tolerância das diatomáceas a metais.
Diatoms are unicellular eukaryotic photosynthetic organisms whose relevance as biomonitor species have long been established, either by ecological indexes, or by tolerance and other toxicity tests, based on ecological properties. The silicified cell wall of diatoms (frustule), is the most visible and distinguished characteristic of these organisms, providing species identification, and indication of environmental stressors, due to the induction of abnormal frustule formation. These teratologies are the consequence of perturbation in the biosilicification process, and can occur either by artificial growth, heavy metal contamination, or pesticides. Amongst the frustule abnormality inductors, metals such as cadmium are the most relevant class due to both anthropogenic and natural occurrence in nature and by the high toxicity relative to the small amounts present in the habitat. Although the process of frustule formation is not completely understood, in the last years it has been published data that show the existence of proteins in the frustules, some of them contributing to the biosilicification. The study of alterations induced by cadmium to the quantity, variety, and ratio of proteins present in frustules were the objectives of this work, along with cadmium quantification in the frustule fractions. Results showed that Cd increased frustule protein content. About 80% of the peptides increased their expression in the presence of Cd . Cadmium was mostly retained extracellularly, and 85% was bound to frustulines. Frustulins were found to be extremely important to the cell defense against cadmium stress, providing two putative novel mechanisms of cadmium tolerance: strengthening of frustules, and protection against Cd, through extracellular metal chelation. These results show that frustulines can play a leading role in the tolerance of diatoms to metals.
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Woods, Scott Andrew. "Behavioral and physiological effects of oxidative stress throughout the lifecycle of Drosophila sod1 mutants". Thesis, University of Iowa, 2017. https://ir.uiowa.edu/etd/6014.

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Oxidative stress has a degenerative effect on neuronal health. Mutations in the copper zinc superoxide dismutase (SOD1), an important antioxidant, have been found in patients suffering from amyotrophic lateral sclerosis (ALS). Classical EMS induced mutations to SOD1 in Drosophila show similar loss of motor coordination and shortened lifespan seen in humans. A study of newly created human ALS point mutants along with the classic alleles show similar phenotypes in their neurodegeneration. I examined markers of oxidative stress, neuronal health and behavioral phenotypes throughout the lifecycle of aging flies. Larvae were largely found to be unaffected by mutations in SOD1, with no measured increase in ROS level over wild type (WT) flies. Mutant pupae were found to have two major defects in their circadian eclosion rhythm and their fundamental ability to eclose from the pupal casing. Adults showed the classic reduced lifespan and motor abilities. To further examine the health on non-glutamatergic synapses electroretinograms (ERGs) were recorded at different levels of survivorship indicated by Kaplan-Meier Survival curves. These ERGs show that the histaminergic synapses they record have greater degeneration in aging SOD1 mutants than in WT flies. This is true for their chronological age as well as their biological age. There was coinciding disruption of the photo transduction pathway of the photoreceptors that coincided with degeneration at the synapse. This demonstrates the separate degenerative effect of high levels of oxidative stress impart separate for the normal aging process.
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Hanson, Miranda Leah. "Prenatal cadmium exposure dysregulates sonic hedgehog and Wnt/beta-catenin signaling in the thymus resulting in immunomodulatory effects". Morgantown, W. Va. : [West Virginia University Libraries], 2009. http://hdl.handle.net/10450/10625.

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Thesis (Ph. D.)--West Virginia University, 2009.
Title from document title page. Document formatted into pages; contains vii, 250 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references.
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Jinadasa, N., of Western Sydney Hawkesbury University, of Science Technology and Agriculture Faculty y School of Horticulture. "Cadmium effects on vegetables : production, physiology and biochemistry". THESIS_FSTA_HOR_Jinadasa_K.xml, 1998. http://handle.uws.edu.au:8081/1959.7/456.

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Cadmium (Cd) is absorbed through the lungs and the digestive tract; however, for most human non-smokers, the major route of Cd entry into the body is by ingestion. Perhaps 5% of ingested Cd is absorbed and once absorbed, Cd accumulates mostly in the liver and kidneys, where it can cause a variety of health problems. This applies equally to grazing stock. The major entry point of Cd into the food chain is therefore uptakes of traces of Cd by crop plants. This thesis focuses on Cd in vegetables. The study was conducted in an Australian context, where geogenic Cd contributions to soils are typically low. Most of the Cd in soils on Australian vegetable farms originates from materials added to boost crop production. Phosphate fertilisers were and remain the dominant Cd source. Most Australian soils are P-deficient and high rates of P fertiliser are essential for successful vegetable cropping. The P fertilisers used throughout Australia were formerly made from guano deposits mined on Pacific Islands. These contained high percentages of Cd. Current rock sources contain lower Cd concentrations. Studies showed that all the vegetable samples which contained excessive Cd concentrations were leafy vegetables, including cabbage, lettuce, silverbeet, parsley and bok choy. Cadmium impaired photosynthesis; reduced dry weight of the whole plant; slowed leaf elongation rate; decreased the length of fully expanded leaves; slowed the rate at which new leaves appeared; and altered foliar concentrations of Zn, Mn, Cu, Ca and S. These profound changes affected all parts of the plant; consequently, Cd did not affect the proportion of dry weight partitioned to the roots, stems and leaves.
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Brandt, Clarissa. "The Effects of Cadmium and Lead on Phaseolus vulgaris". University of the Western Cape, 2012. http://hdl.handle.net/11394/5096.

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Magister Scientiae (Biodiversity and Conservation Biology) - MSc (Biodiv and Cons Biol)
The demand for better quality produce by consumers is on the increase, as higher heavy metal concentrations pose a problem in agriculture. They result in decreased yield and unsuitable food for human consumption. This brings about a negative economic effect as such products become unprofitable on the domestic or export markets thus affecting productivity of farms.Four heavy metals (Cd, Cu, Pb and Zn) have been shown to be a problem in the farming areas in Cape Town. Pot and field studies were carried out on the effects and concentrations of cadmium and lead on Phaseolus vulgaris. Field studies included collecting plant samples from the Joostenbergvlakte/ Kraaifontein farming areas and measuring the heavy metal concentrations within the different organs of the plants. Pot experiments were carried out, where Phaseolus vulgaris var. Contender were grown and then heavy metals were administered to these plants together with two heavy metal mitigation techniques, precipitation with phosphate and mobilisation with EDTA to see if they were successful in combating heavy metal pollution.Samples taken from farms in the Joostenbergvlakte/ Kraaifontein area revealed that cadmium, lead and zinc concentrations were higher than the legal standard in the edible fruits. In the pot experiment, results revealed that cadmium reduced the chlorophyll index as well as the shoot fresh mass and changes in mineral uptake were seen. Lead did not affect growth or the chlorophyll index. The high cadmium treatment resulted in a marked increase in sodium concentration in the shoots. The phosphate treatments and EDTA treatments both resulted in increased cadmium concentrations in the roots and shoots. The higher phosphate and lead treatments also reduced lead concentrations in the roots. Low phosphate and the EDTA treatments increased the shoot sodium concentrations.
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Pinho, Francisco Carvalho Vieira. "Cytotoxic and genotoxic effects of cadmium in human osteoblasts". Master's thesis, Universidade de Aveiro, 2011. http://hdl.handle.net/10773/8061.

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Mestrado em Biologia Aplicada - Biologia Molecular e Celular
Due to industrialization, cadmium has been increasingly accumulated in soil, water and air, and consequently the food chain, thus, being responsible for many diseases. In humans, damages to several organs and carcinogenic effects take place. However, the mechanisms underlying the bone diseases remain unknown, and so, this work aims to evaluate cytotoxic and genotoxic effects of cadmium in human osteoblasts cell line MG-63. Cells were exposed to 0 μM, 20 μM and 50 μM CdCl2 for 24 and 48 hours. Cell proliferation / viability was determined by the MTT assay, cell cycle effects were evaluated by flow cytometry, and DNA damage was assessed by the comet assay. After both times of exposure, cell viability decreased in both cadmium doses, although cell cycle progression alterations were not detected. However, cadmium lead to clastogenic effects and DNA damage in cells exposed to the cadmium dose of 50 μM, for 48 h. In conclusion, at 20 μM and 50 μM and for the periods tested cadmium chloride induced cytotoxic and genotoxic effects on MG-63 cell line, as it decreased cell viability, induced DNA damage and clastogenicity, though it did not change cell cycle progression.
Devido à industrialização, a contaminação ambiental por metais como o cádmio tem aumentado no solo, água e ar. Consequentemente, a cadeia alimentar é afetada e, desta forma, o cádmio surge como agente carcinogénico e como causador de algumas doenças relacionadas com lesões em vários órgãos. Contudo, os mecanismos subjacentes a doenças ósseas ainda não se encontram totalmente desvendados, e assim neste trabalho, pretende-se avaliar os efeitos citotóxicos e genotóxicos do cádmio em osteoblastos humanos, na linha celular MG-63. As células foram expostas a 0 μM, 20 μM e 50 μM de cloreto de cádmio durante 24 e 48 horas. A proliferação / viabilidade celular foi avaliada pelo ensaio MTT, os efeitos na progressão do ciclo celular por foram avaliados por citometria de fluxo e os danos no DNA pelo ensaio de cometas. Após ambos os tempos de exposição a 20 μM e 50 μM de cloreto de cádmio, as células sofreram uma diminuição da viabilidade celular e não foram observadas alterações na progressão do ciclo celular. No entanto, o cádmio conduziu a efeitos clastogénicos e danos no DNA em células expostas à concentração de 50 μM, após 48 h de exposição. Concluindo, as concentrações 20 μM e 50 μM de cloreto de cádmio para os períodos testados, induziram efeitos citotóxicos e genotóxicos nas células da linha MG-63, dado que conduziram a uma diminuição da sua viabilidade, danos no DNA e clastogenicidade, não havendo, contudo, alterações na progressão do ciclo celular.
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Haider, Syed Raza. "Effects of chronic cadmium exposure on macrophage function in mice". Thesis, University of Essex, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.236639.

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Школьна, Ірина Іванівна, Ирина Ивановна Школьная, Iryna Ivanivna Shkolna, Андрій Миколайович Лобода, Андрей Николаевич Лобода, Andrii Mykolaiovych Loboda, Віталій Едуардович Маркевич, Виталий Эдуардович Маркевич y Vitalii Eduardovych Markevych. "Protective role of the placenta against toxic effects of cadmium". Thesis, Sumy State University, 2016. http://essuir.sumdu.edu.ua/handle/123456789/46325.

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The placenta has a number of features that ensure the passage of many biological substances to the fetus, as well as the function of barrier for certain substances. According to researchers, it can be used as a marker of unfavorable environmental action.
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Campos, Diana Marina Gomes de. "Effects of cadmium on a model stream detritus processing chain". Master's thesis, Universidade de Aveiro, 2012. http://hdl.handle.net/10773/10276.

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Mestrado em Biologia Aplicada - Microbiologia Clínica e Ambiental
A integridade ecológica dos ecossistemas é na maior parte das vezes avaliada em termos de ocorrência de espécies e composição das comunidades e não em termos de relações tróficas entre espécies ou parâmetros funcionais. O processamento de detritos é um processo ecológico vital para os ecossistemas lóticos, mediado por microrganismos e invertebrados aquáticos. Nestas cadeias tróficas, os invertebrados fragmentadores contribuem para a ciclo de nutrientes através da transformação de matéria orgânica particulada grosseira em matéria orgânica particulada fina que serve de alimento para os invertebrados coletores. O nosso objetivo passou por avaliar os efeitos combinados do cádmio e da alteração na qualidade dos recursos (espécie de folha) na cadeia trófica de detritos e na interação entre fragmentadores – coletores. Em laboratório folhas de amieiro (espécie nativa) e de eucalipto (espécie exótica) foram condicionadas em diferentes concentrações de cádmio (0, 50 e 200 μg/L). A comunidade microbiana presente nas folhas provenientes de diferentes tratamentos foi analisada através da técnica molecular DGGE e a taxa de respiração microbiana foi medida. Sericostoma vittatum (tricóptero fragmentador) e Chironomus riparius (um díptero coletor) foram expostos às mesmas concentrações de cádmio e alimentados com discos de folhas correspondentes. Foram avaliados, em microcosmos, o crescimento de C. riparius e a perda de peso das folhas. O cádmio afetou o condicionamento das folhas e provocou alterações na diversidade de fungos em ambas as espécies de folhas. A comunidade microbiana presente no amieiro e no eucalipto mostrou reagir de maneira diferente ao cádmio. Este apenas afetou a decomposição das folhas de amieiro através da redução da alimentação dos invertebrados e também afetou o crescimento larvar de C. riparius. Esta espécie mostrou não ser exclusivamente coletora sendo capaz de se alimentar de folhas de amieiro na ausência de invertebrados fragmentadores. Contudo os fragmentadores mostraram promover o crescimento dos coletores no tratamento com eucalipto como fonte de alimentação. Estes resultados levam-nos a crer que a hipótese de facilitação entre fragmentadores - coletores pode ser tida como verdadeira mas que depende da qualidade dos recursos bem como das espécies de detritívoros presentes. Os resultados sugerem ainda que as cadeias de processamento de detritos podem ser ferramentas valiosas em ecotoxicologia de comunidades. Mais estudos com a utilização de diferentes espécies de detritívoros e de outros stressores (naturais e antropogénicos) deverão continuar para melhor avaliar possíveis efeitos indiretos de contaminantes ao longo destas cadeias de processamento de detritos sob diferentes cenários ecológicos.
The ecological integrity of ecosystems is often evaluated in terms of species occurrence and composition of communities and not in terms of trophic relationships between species or functional parameters. The processing of detritus is a vital ecological process for freshwater ecosystems, mediated by microorganisms and aquatic invertebrates. Here, shredders contribute to the nutrient cycle, transforming coarse into fine particulate organic matter which serve as food for collectors. The aim of this work was to evaluate the combined effects of cadmium exposure and changes in resource quality (leaf species) on detritus trophic chain and on shredder–collector interactions. In the laboratory, alder leaves (native species) and eucalyptus (exotic species) were conditioned at different cadmium concentrations (0, 50 and 200 μg/L). The microbial community present in leaves from the different treatments was analyzed by molecular DGGE technique and microbial respiration rates were measured. Sericostoma vittatum (a caddisfly shredder) and Chironomus riparius (a midge collector) were exposed to the same concentrations of cadmium and fed the corresponding leaf discs. C. riparius growth and leaf weight loss were evaluated in these multispecies microcosms. Cadmium exposure affected the leaf conditioning and the reduction in fungal diversity in both leaf species was clear. Cadmium affected the decomposition of alder leaves through reductions in invertebrate feeding and also impaired C. riparius’ growth. C. riparius showed to be a non-exclusive collector and capable of feeding on alder leaf discs in the absence of shredders. However shredders appear to promote collectors growth in treatments with eucalyptus as food source.. The observed pattern suggest that shredder-collector facilitation hypothesis can hold true and also that it might be dependent on resource quality and detritivore species present. The results suggest that detritus processing chains can be valuable tools to community ecotoxicology. We advocate that these investigations should continue with the use of different detritivore species and stressors (natural and anthropogenic) to improve our current understanding of indirect effects of contaminants in detritus based food webs under different ecological scenarios.
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Wang, Guangyao (Sam), Michael Ottman y Rufus L. Chaney. "Effects of Zn fertilizer on cadmium accumulation in durum wheat". College of Agriculture, University of Arizona (Tucson, AZ), 2012. http://hdl.handle.net/10150/211139.

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Proposed reduction in maximum allowable cadmium (Cd) level in wheat grain from 0.2 to 0.15 ppm by European Union (EU) could affect Arizona wheat growers substantially. The possible breeding programs and management practices needs to be developed to keep the industry competitive for this major market. In this study, we used two durum wheat cultivars (Ocotillo representing higher Cd genotypes and Havasu representing lower Cd genotypes) to study the potential of Zn fertilizer (as ZnSO₄ and ground tire rubber) to reduce Cd uptake in durum wheat at Yuma Ag Center. While cadmium level in the two varieties were different significantly, applying ZnSO₄ or ground rubber did not affect grain cadmium level, grain yield, or protein content significantly.
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Murphy, Matthew M. "Investigating the Effects of CyPPA on Small-Conductance Calcium-Activated Potassium Channels in SOD1G93A Transgenic Mouse Model". Wright State University / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=wright1589929963490428.

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Petersson, Grawé Kierstin. "Lactational transfer of cadmium in rodents : CNS effects in the offspring /". Uppsala : Dept. of Pharmacology and Toxicology, Swedish Univ. of Agricultural Sciences, 2003. http://epsilon.slu.se/v150.pdf.

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Wigginton, Andrew Joseph. "SOME EFFECTS OF CADMIUM ON SELECT CRAYFISH IN THE FAMILY CAMBARIDAE". UKnowledge, 2005. http://uknowledge.uky.edu/gradschool_diss/271.

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A series of acute (96h) toxicity tests were conducted on six species of crayfish inthe family Cambaridae. Toxicity values fell into a sensitive group comprising Orconectesplacidus and Procambarus acutus (LC 50= 0.368mg Cd/L - 0.487mg Cd/L; LC10= 0.048mg Cd/L - 0.092 mg Cd/L) and tolerant group comprising O. juvenilis, O. virilis, P.alleni, and P. clarkii (LC 50= 2.44 mg Cd/L - 3.30 mg Cd/L; LC10= 0.386 mg Cd/L -0.947 mg Cd/L). For juvenile crayfish, the LC50 and LC10 values were as follows: O.juvenilis, 0.060 and 0.014 mg Cd/L; O. placidus, 0.037 and 0.002 mg Cd/L; P. clarkii,0.624 and 0.283 mg Cd/L. Cd exposure decreased molting success highlighting theimportance of this sensitive process. Behavioral responses were assessed in O. placidus,O. virilis, P. acutus, P. alleni, and P. clarkii. The tail-flip predator avoidance behaviorwas significantly reduced by cadmium exposure. In most species tested, the claw raisedefensive behavior was significantly increased by Cd exposure. Between species, as bodymass increased, the tail-flip response frequency decreased, and the claw-raise responseincreased in frequency. P. clarkii was also analyzed for the effect of Cd exposure onheart rate and response to two stimuli. The data indicate that heart rate may be a usefulphysiological marker of Cd toxicity. The major organ systems were dissected fromsurvivors of four adult crayfish toxicity tests (O. juvenilis, O. placidus, P. acutus, P.clarkii) and analyzed for metal content. Cadmium tissue content correlated with Cdexposure. Cadmium accumulated more in the hepatopancreas, gills and green glands ofsensitive species than in tolerant species. Zn showed negative correlations with Cdexposure in the hepatopancreas. Cu increased in green glands, gills, and hemolymph and,in some cases, decreased in the hepatopancreas. Ca, Fe, Mg, and Zn also showedsignificant trends. Zn accumulated in the exposure water over 24h. These data indicatethat Cd may displace Cu and/or Zn in the hepatopancreas and the displaced metal thenmay move into other tissues, especially the gills and green glands, possibly to beexcreted.
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16

Alexander, Leslie M. "Some effects of copper and cadmium on Enteromorpha intestinalis (L.) Link". Thesis, Heriot-Watt University, 1987. http://hdl.handle.net/10399/1014.

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Valori, Federico. "Effects of root exudates on cadmium bioavailability in the rhizosphere : assessment of cadmium toxicity to plants and microorganisms, and soil remediation". Bordeaux 1, 2006. http://www.theses.fr/2006BOR13151.

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Des sols contaminés uniquement en Cd, depuis une longue période, ont d'abord été utilisés pour évaluer les effets d'exsudats racinaires de faible masse moléculaire, libérés dans un système modèle par un filtre placé à la surface du sol, sur les biomasses microbiennes carbonées et azotées, la respiration microbienne, le pool inorganique d'N et la biodisponibilité de Cd dans la rhizosphère (BIOMET®). L'utilisation d'une espèce végétale, Holcus lanatus L. , pour la phytoremédiation aidée de sols contaminés en Cd a été étudiée de façon préliminaire en solution hydroponique sur 4 semaines. Les plantes, dont le système racinaire a été lavé, ont été placées dans une solution nutritive simulant la concentration en Cd extrait et le pH des parcelles d'origine. La concentration et la quantité de Cd ont été quantifiées dans les parties aériennes, les feuilles et les racines. On a mesuré les activités enzymatiques Guaiacol peroxidase dans les feuilles, ainsi que leur densité en chlorophylle et caroténoïdes totaux. L'assainissement des sols contaminés en Cd a été étudié en utilisant une technique de stabilisation in situ basée sur l'apport au sol de l'un des 3 composés inorganiques suivants: beringite + grenailles d'acier, sépiolite, et bentonite. La concentration en Cd a été mesurée dans la solution du sol (Rhizon) au cours des premiers jours suivants l'amendement du sol et après 6 mois. L'efficacité de la remédiation des sols contaminés en Cd par stabilisation in situ a été évaluée en vase de végétation placés sous serre, avec 3 végétaux de sensibilité différente à l'exposition au Cd (sensible: Phaseolus vulgaris, moyennement tolérante: Holcus lanatus, tolérante: Lactuca sativa).
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18

Oliver, Danielle P. "The effects of farm management practices on cadmium concentration in wheat grain /". Title page, contents and summary only, 1994. http://web4.library.adelaide.edu.au/theses/09A/09ao48.pdf.

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19

Westcott, Fay Mostyn. "The effects of low-level chronic cadmium exposure on a freshwater leech". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/mq24710.pdf.

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Daniels, Susan G. "Effects of cadmium toxicity on population dynamics of the blowfly Lucilia sericata". Thesis, University of Reading, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.240261.

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21

Hurk, Peter van den. "Interactive effects of cadmium and benzo(a)pyrene in mummichog (Fundulus heteroclitus)". W&M ScholarWorks, 1998. https://scholarworks.wm.edu/etd/1539616705.

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22

van, den Hurk Peter. "Interactive effects of cadmium and benzo(a)pyrene in mummichog (Fundulus heteroclitus)". W&M ScholarWorks, 1998. https://scholarworks.wm.edu/etd/1539616888.

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When animals are exposed to mixtures of environmental pollutants, it is generally assumed that the toxic effects of the individual components are additive. However, examples of synergistic and antagonistic effects have been described. to study the mechanisms of interaction between a metal and a polycyclic aromatic hydrocarbon, mummichog (Fundulus heteroclitus) were injected with combinations of cadmium (Cd) and benzo (a) pyrene (BP). Measured effect parameters were: mortality, BP-metabolite production in isolated hepatocytes and microsomes, hepatic induction of CYP1A (the BP metabolizing enzyme) and metallothionein (the Cd binding protein), and biliary excretion of BP-metabolites. The mortality data demonstrated that both synergistic and antagonistic effects can occur. A Cd dose of 0.32 mg/kg significantly reduced the expected mortality caused by BP. In contrast, a BP dose of 10 mg/kg significantly increased the toxicity of Cd above the expected mortality. to study the mechanisms of these interactive effects, liver cells (hepatocytes) were isolated from fish that were previously injected with combinations of Cd and BP. These cells were exposed to radiolabeled BP to study the rate of BP metabolism, and the formation of BP-metabolites. Cadmium exposure had an overall inhibiting effect on the metabolism of BP. No effects of Cd were observed on the formation of individual metabolites. to distinguish between direct interference of Cd with CYP1A at the active site versus indirect interference by inhibiting CYP1A induction, microsomal preparations were evaluated for enzyme activity and enzyme concentration. While there was no direct effect of Cd on enzyme catalytic activity, there was an effect on CYP1A production. The demonstrated inhibition of BP metabolism by Cd would suggest a reduced excretion of BP-metabolites. However, analysis of bile and water samples after fish were injected with radiolabeled BP demonstrated an enhanced biliary excretion of conjugated BP-metabolites under influence of Cd. Cadmium exposure caused a significant induction of hepatic metallothionein in the fish. When BP was dosed together with Cd, the induction of MT was inhibited. The hypothesis that reactive BP metabolites would compete with Cd for binding sites on MT could not be confirmed. There was no measurable binding of BP to MT.
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23

Robinson, R. y Phillip R. Scheuerman. "Effect of Cadmium and Copper on Rabbit Sperm Cells". Digital Commons @ East Tennessee State University, 1996. https://dc.etsu.edu/etsu-works/2911.

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24

Cappello, V. "ANALYSIS OF NEUROMUSCULAR JUNCTIONS AND EFFECTS OF NANDROLONE ADMINISTRATION IN A MOUSE MODEL FOR ALS". Doctoral thesis, Università degli Studi di Milano, 2012. http://hdl.handle.net/2434/170264.

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Several lines of evidence indicate that neuromuscular junction (NMJ) destruction and disassembly is an early phenomenon in the amyotrophic lateral sclerosis (ALS) neurodegenerative disease. Here we analyzed by confocal and electron microscopy the NMJ structure in the diaphragm of Superoxide dismutase (SOD)1 G93A mice at symptom onset and we compared these observation with animals sacrificed at the pathological end stage. In young transgenic mice, which provide a model for familial ALS, the present findings showed marked denervation both in the diaphragm and in the gastrocnemius, which partially spares soleus muscle. At the clinical end stage even the soleus is slight denervated, but less severely than other muscles. In addition, the size of the synaptic vesicle (SV) pool was found reduced and alterations of mitochondria were observed in approximately 40% of the remaining presynaptic terminals. Treatment of SOD1 G93A mice with the anabolic steroid nandrolone during the presymptomatic stage preserved the diaphragm muscle mass and features indicative of synaptic activity, represented by the number of vesicles docked within 200 nm from the presynaptic membrane and area of acetylcholine receptor clusters. Furthermore, structural preservation of mitochondria was documented in presynaptic terminals, but innervation of diaphragm muscle fibers was only slightly increased in nandrolone-treated SOD1-mutant mice. Altogether the results point out and define fine structural alterations of diaphragm NMJs in the murine model of familial ALS at symptom onset, and indicate that nandrolone may prevent or delay structural alterations in NMJ mitochondria and stimulate presynaptic activity but does not prevent muscle denervation in the disease.
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25

Milton, Adrian Mark. "Heavy metals in contaminated grassland ecosystems : distribution, transfer and effects". Thesis, University of Liverpool, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.266222.

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26

Liu, Xixi. "Effects of Ammonia and Organic Ligands to Cadmium (Cd) Toxicity on Marine Phytoplankton". Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for biologi, 2012. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-16824.

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The effects of ammonia to Cd toxicity on marine phytoplankton have been studied. The phytoplankton biomass was significantly increased at higher ammonia flux after high Cd level exposure, which indicated high ammonia decreased Cd toxicity on phytoplankton. In addition, DGT labile Cd concentration was linear decreased with increasing ammonia flux in day 8, while DGT labile Cd concentration was increased at higher ammonia flux in day 12. Cd complexation capacity in seawater of Cd treatment was higher over 100 times than Cd complexation capacity in seawater of without Cd treatment. And high ammonia increased Cd complexation capacity in seawater after high Cd exposure in day 8, while Cd complexation capacity in seawater of Cd treatment was decreased due to high ammonia in day 12. Therefore, ammonia influences the amount of DOM released by phytoplankton and the Cd complexation with organic ligands, and finally leads to affect Cd bioavailability and toxicity on phytoplankton.
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27

Brumec-Turk, Vesna. "The effects of cadmium and zinc exposure on the freshwater amphipod Hyalella azteca". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ34945.pdf.

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28

Alfvén, Tobias. "Bone and kidney effects from cadmium exposure : dose effect and dose response relationships /". Stockholm : Karolinska Univ. Press, 2002. http://diss.kib.ki.se/2002/91-7349-341-4.

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29

Wold, Marissa K. "Effects of Early Cadmium and Selenium Exposure on Zebrafish Neural Development and Behavior". Thesis, The University of North Dakota, 2018. http://pqdtopen.proquest.com/#viewpdf?dispub=10843993.

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Cadmium is a naturally-occurring trace metal frequently found in soil that has been linked with increased prevalence of various cancers via formation of reactive oxygen species. Selenium, a widely-prevalent metalloid, antagonizes the detrimental action of cadmium and has been demonstrated to exert a rescue effect. The present work focuses on the short- and long-term effects of exposure to ecologically-relevant cadmium concentrations on zebrafish development and behavior, and compares this to co-treatment with selenium. This study has demonstrated a decrease in overall brain size, specifically telencephalic area, in response to cadmium exposure, and has documented a sparing effect of selenium treatment. A similar effect is seen in larval body size and eye diameter. This study has also reported an effect on spinal morphology and hatching delay. Longitudinally, cadmium treatment affects survival to six months, and has an impact on adult brain metrics. The results of behavioral assay indicate an effect of larval cadmium exposure on adult learning behavior, as well as a rescue effect of selenium.

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30

Mckarus, J. N., Phillip R. Scheuerman, G. R. Lanza y M. A. Eckels. "Effects of Water Quality on the Influence of Cadmium to Microbial Enzyme Activity". Digital Commons @ East Tennessee State University, 1994. https://dc.etsu.edu/etsu-works/2899.

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31

Bidston, Caroline. "The effects of metal pollution on the spectral reflectance of plants". Thesis, University of Reading, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.314319.

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32

Todd, Keith Denham. "The effects of cadmium on the early developmental stages of turbot, Scophthalmus maximus L". Thesis, University of Stirling, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.244451.

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33

Sabokbar, Afsaneh. "Effects of chronic cadmium exposure on the immune responses of ageing C57BL/10cSn mice". Thesis, University of Essex, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.238431.

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34

Stanley, Jacob K. "Laboratory and field studies of cadmium effects on Hyalella azteca in effluent dominated systems". Thesis, University of North Texas, 2003. https://digital.library.unt.edu/ark:/67531/metadc4291/.

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Laboratory single-species toxicity tests are used to assess the effects of contaminants on aquatic biota. Questions remain as to how accurately these controlled toxicity tests predict sitespecific bioavailability and effects of metals. Concurrent 42-day Hyalella azteca exposures were performed with cadmium and final treated municipal effluent in the laboratory and at the University of North Texas Stream Research Facility. Further laboratory testing in reconstituted hard water was also conducted. Endpoints evaluated include survival, growth, reproduction, and Cd body burden. My results demonstrate that laboratory toxicity tests may overestimate toxicity responses to cadmium when compared to effluent dominated stream exposures. Discrepancies between endpoints in the three tests likely resulted from increased food sources and decreased cadmium bioavailability in stream mesocosms
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35

Gunnarsson, David. "Reproductive toxicology of endocrine disruptors : effects of cadmium, phthalates and phytoestrogens on testicular steroidogenesis". Doctoral thesis, Umeå : Department of Molecular Biology, Umeå University, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-1876.

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36

Sandrin, Todd Ryan. "Naphthalene biodegradation in a cadmium cocontaminated system: Effects of rhamnolipid, pH, and divalent cations". Diss., The University of Arizona, 2000. http://hdl.handle.net/10150/289199.

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Forty percent of hazardous waste sites on the U.S. Environmental Protection Agency's National Priority List (NPL) are cocontaminated with organic and metal pollutants. Conventional approaches to remediating these sites are costly and often ineffective. Bioremediation is a promising, cost-effective alternative but metal toxicity at cocontaminated sites may limit its efficacy. The research described in this dissertation provides two new possible approaches to enhance the bioremediation of cocontaminated environments and sheds light on the relationship between metal concentration and inhibition of organic pollutant biodegradation. In Objective 1, a rhamnolipid biosurfactant was employed to increase naphthalene biodegradation in the presence of cadmium. The biosurfactant reduced bioavailable cadmium concentrations and increased naphthalene bioavailability. Neither of these phenomena, however, fully accounted for the ability of rhamnolipid to reduce cadmium toxicity. The ability of rhamnolipid to alter the cell surface appeared critical to its ability to mitigate toxicity. In Objective 2, pH was lowered to increase naphthalene biodegradation in the presence of cadmium. Reductions in pH had previously been reported to mitigate metal toxicity, but the mechanism of such reductions warranted elucidation. Previous studies implicated the formation of monovalent hydroxylated metal in the mechanism by which pH mediates toxicity. Results of this study, however, suggest that the importance of such species in determining toxicity may be much less than that of the increased competition between hydrogen and metal ions for binding sites on the cell surface at reduced pH. An indirect relationship between metal concentration and inhibition of organic biodegradation was revealed in Objective 3. Naphthalene biodegradation was more sensitive to cadmium concentrations of 10 and 37.5 mg/L than 100 mg/L. For this reason, we investigated whether naphthalene biodegradation could be increased in the presence of a toxic concentration of cadmium by raising the total metal concentration to a higher, but relatively less toxic concentration. Only elevated concentrations of zinc reduced cadmium toxicity. High but less toxic levels of metal may more rapidly induce the transcription of a gene(s) important in metal efflux than lower more toxic concentrations.
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37

De, Lisle Peter F. "The effects of salinity on cadmium toxicity to the bay mysid, Mysidopsis bahia Molenock". W&M ScholarWorks, 1988. https://scholarworks.wm.edu/etd/1539616625.

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The effects of salinity on cadmium toxicity to the bay mysid, Mysidopsis bahia Molenock were studied in a series of experiments examining salinity tolerance, effect of salinity on intermolt period, osmoregulatory capacity, interaction of salinity with acute cadmium toxicity, role of changes in cadmium speciation, modification due to calcium antagonism and effects of cadmium on osmoregulatory ability. Upper and lower tolerance limits increased with increasing acclimation salinity. Intermolt duration decreased slightly with increasing salinity. Mysidopsis bahia osmoregulates at salinities from 5 to 37&\perthous& and exhibits an isosmotic point of 24&\perthous&. Hemolymph osmolality attained steady-state condition by 95 min post-transfer to high and low salinity water. The 96-h LC&\sb{lcub}50{rcub}& (as total cadmium, Cd&\sb{lcub}\rm T{rcub}&) increased in a general linear fashion with salinity. When toxicity was expressed in terms of free cadmium ion (Cd&\sp{lcub}2+{rcub}&) rather than Cd&\sb{lcub}\rm T{rcub}&, CdCl&\sp+& or CdCl&\sb2& only a slight salinity effect was apparent, suggesting that Cd&\sp{lcub}2+{rcub}& is the primary toxic species. Mysids were more tolerant of Cd&\sp{lcub}2+{rcub}& at an intermediate salinity of 22&\perthous&. Toxicity of Cd&\sp{lcub}2+{rcub}&, when varied by use of the artificial ligand nitrilotriacetic acid (NTA), was independent of Cd&\sb{lcub}\rm T{rcub}& concentration at a given salinity but increased with increasing salinity and/or NTA concentration. Calcium exerted a sparing effect on Cd&\sp{lcub}2+{rcub}& toxicity although the effect was not as pronounced as were effects due to Cd&\sp{lcub}2+{rcub}&-salinity interactions. Molt rate was significantly increased by Cd&\sp{lcub}2+{rcub}&-salinity interaction. It is postulated that the increase in apparent molt rate may at least partially explain the residual salinity effect that is observed even when speciation and calcium effects are considered. No significant effects on hemolymph osmoregulation were observed following exposure for up the 48 h to Cd&\sp{lcub}2+{rcub}& levels approximating the 96-h LC&\sb{lcub}50{rcub}& at 12 to 30&\perthous& salinity.
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38

Ressing, Sara Marlene. "Effects of heavy metals on two small mammal species". OpenSIUC, 2012. https://opensiuc.lib.siu.edu/theses/947.

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Research on the chronic effects of toxic chemicals on individuals, populations, communities, and ecosystems is imperative to regulate pollutants and preserve threatened species and habitats. I designed a two-pronged study to investigate the effects of heavy metal contaminants on small mammal populations, communities and body condition. To compare population and community metrics, I conducted a year-long mark-and-release study from over 5,400 trap nights on a contaminated and reference site within Crab Orchard National Wildlife Refuge, a Superfund site. During the second phase, I compared contaminant residues to body condition in 29 white-footed mice (Peromyscus leucopus) and 21 southern short-tailed shrews (Blarina carolinensis) from the Refuge and from three reference sites. Body weight, age structure, trapping success or species diversity did not differ between sites. Mice from the contaminated site were more abundant with lower reproduction (as number of juveniles per adult female). Cadmium in both livers and kidneys of mice and shrews was significantly greater on the contaminated site. Elevated renal cadmium in mice (96 ± 79 mg/kg dry weight) and shrews (242 ± 166 mg/kg dry weight) from the contaminated site could likely impair physiologic functions with long-term effects. For white-footed mice, increasing renal copper, lead, and nickel were good predictors of low ash, water, and protein but did not correlate significantly with crude lipid content. In shrews, however, metals either showed no relationship or, in the case of renal cadmium and copper were positively related to body condition as increased protein content. Simply comparing animals from reference versus contaminated sites provided few insights into overall community structure or population dynamics of white-footed mice. While metals explained as much as 40% of body condition (ash) in mice, findings in both species are counter-intuitive or refute predictions. Future studies should include manipulative field experiments that pair higher-resolution, biologic responses such as histologic and biomarker assays with population and community dynamics.
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39

Smith, Franz E. "Physiological effects of copper, cadmium and reduced salinity on intertidal and cultivated Perna canaliculus mussels". Thesis, University of Canterbury. School of Biological Sciences, 2008. http://hdl.handle.net/10092/2961.

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The endemic mussel Perna canaliculus is the most valuable aquaculture product in New Zealand. Limited information has been compiled on physiological functions such as clearance, respiration and excretion of this species. Scope for Growth (SfG) which is the difference between the energy acquired from feeding and the expenditure of energy on respiration and excretion has been determined for this species from various locations in New Zealand. Existing information suggests that SfG shows limited correlation with the distribution, origin or contamination of mussels in their habitats. Therefore, the aim of the thesis research was to investigate the SfG of farm and intertidal mussels and compare how these values responded to challenges from reduced salinity and exposure to the trace metals copper and cadmium. Preliminary experiments on mussel respiration rates (ml O₂ g⁻¹ h⁻¹) showed that recently collected mussels respired at a rate of 0.222 ± 0.013 ml O₂ g⁻¹ h⁻¹ while mussels held for two weeks under laboratory conditions respired at 0.098 ± 0.009 ml 02 g⁻¹ h⁻¹. Respiration rates of recently collected farm and intertidal mussels measured every four hours over 28 hours were also found to be similar. The exponent (b) in the allometric relationship between respiration and dry weight was 0.5766. Respiration rate and condition of mussels which were maintained with feeding for two month was greater than respiration for mussels which were not fed over this time period. Specific dynamic action (SDA) was found to be the difference between the pre-feeding respiration rate of 0.15 ± 0.02 ml O₂ g⁻¹ h⁻¹ and 1.03 ± 0.16 ml O₂ g⁻¹ h⁻¹ at one hour after feeding. Respiration returned to prefeeding rates between two and four hours after feeding was stopped. Mussels exposed to 0, 1, 10 and 100 µg Cu L⁻¹ showed no physiological effects of copper. Exposure of intertidal mussels to 1,000 µg Cu L⁻¹ caused 100% mortality after three days and exposure to 500 µg Cu L⁻¹ caused 100% mortality after seven days. There was 100% mortality of farm mussels exposed to either 500 µg Cu L⁻¹ or 1,000 µg Cu L⁻¹ after three days. The time for 50% mortality (LT50) of intertidal mussels exposed to 500 µg Cu L⁻¹ was 3.4 days. For an exposure of 50 µg Cu L⁻¹ the LT50 was 5.2 days. SfG of intertidal mussels exposed to 100 µg Cu L⁻¹ decreased by 91% for intertidal mussels in full salinity but SfG of farm or intertidal mussels exposed to cadmium at concentration of 33 µg Cd L⁻¹, 66 µg Cd L⁻¹ or 99 µg Cd L⁻¹ was not affected. Significant effects of cadmium were detected at a concentration of 1,000 µg Cd L⁻¹ which resulted in a reduction in SfG by 60% compared to the controls. The initial experiments showed that copper resulted in lower SfG than cadmium at similar concentrations. For mussels exposed to combinations of 0 and 100 µg Cu L⁻¹ at 34 ppt and reduced salinity (17 ppt) the SfG of intertidal specimens exposed to 100 µg Cu L⁻¹ at 34 ppt was decreased by 85%. SfG of farm mussels exposed to this level of copper was reduced by 70%. The effect of copper on intertidal mussels may be related to the higher clearance rate of these mussels. In the experiments with cadmium, exposure to 1,500 µg Cd L⁻¹ in full salinity resulted in a decline in SfG in excess of 100% for farm mussels but only 91% for intertidal mussels in full salinity. The effect of reduced salinity as the only stressor was also noted in these experiments. In both the copper and cadmium experiments, the treatments exposing mussels to 50% salinity resulted in severe declines in SfG for both farm and intertidal mussels. The decline was 99-100% for farm mussels and 60-82% for intertidal over fourteen days. In addition to salinity, the effect exposure time significantly affected the physiology of intertidal mussels in low salinity. In treatments which combined 50% salinity with either 100 µg Cu L⁻¹ or 1,500 µg Cd ⁻¹ SfG of farm mussels declined into negative values. SfG of intertidal mussels exposed to 100 µg Cu L⁻¹ or 1,500 µg Cd L⁻¹ in low salinity declined by 87% and 98% respectively. The combination of salinity and metals resulted in significant interactive effects but these were not synergistic effects. This suggested that salinity could be a major source of variability in SfG of mussels which are exposed to similar concentrations of metals. The experiments also showed that intertidal mussels possessed greater physiological adaptability to low salinity. This suggests that responses to salinity differ from responses to trace metals. Salinity is therefore an important modulator of the sub-lethal effects of toxic trace metals such as copper and cadmium
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40

Hakki, Hiba Bittar. "Effects of cadmium and zinc on the growth of Tetrahymena pyriformis populations in media 357YG". Instructions for remote access. Click here to access this electronic resource. Access available to Kutztown University faculty, staff, and students only, 1986. http://www.kutztown.edu/library/services/remote_access.asp.

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41

Walley, Justin W. "THE EFFECTS OF LOW-LEVEL CADMIUM TOXICITY ON FIELD AND GREENHOUSE GROWN SOYBEAN (GLYCINE MAX)". Miami University / OhioLINK, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=miami1133229744.

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42

Wu, Pianpian. "Risks of Cadmium Nanoparticles on Estuarine Organisms : Ecotoxicological Effects of Engineered Cadmium Nanoparticles through Biochemical and Behavioral Responses in Two Marine Invertebrates, Nereis diversicolor and Scrobicularia plana". Thesis, Uppsala universitet, Limnologi, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-179100.

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There is an increasing concern over the safety of engineered nanoparticles (ENPs) to humans and the environment. It is important that the environmental risks of these particles to be tested under research and regulatory schemes, e.g. Nano Risks to the environment & Human Health (NanoReTox) under Seventh Framework Programme (FP7) in EU. Due to their unique properties and the fact that their detection and characterization in complex matrices is challenging, classic analytical methods and test approaches for assessing environmental risk may not be appropriate for ENPs. In this paper I present the challenges associated with ENPs exposure to the estuarine environment and the testing of a chosen ENPs to generate data on ecotoxicity in the test estuarine organisms for further consideration of risk assessment of marine environment. Careful consideration was given to the selection of the test materials (benthic organisms Nereis diversicolor and Scrobicularia plana), the test system and the test exposure conditions (CdS ENPs and aqueous CdS added to filtered natural seawater with a concentration of 10 µg L-1). Evaluation of the exposure effects was carried out by behavioral tests (burrowing kinetics and feeding rate) and biochemical responses (quantification of biomarkers). Multispecies Freshwater Biomonitor®  (MFB) tests and GST analysis results show significant differences in between control group and CdS NPs exposure one, indicating that CdS NPs are potential to cause sublethal effects in test organisms. Our knowledge in environmental risk assessment of ENPs is still limited. Coordinated research is required to gain a better understanding of the factors and processes affecting ENP fate and effects in the environment as well as to develop more usable, robust and sensitive methods for characterization and detection of ENPs in environmental systems.
NanoReTox, FP7 NMP Work Programme
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43

Cunha, Joana Carolina Marinho. "Exploring motor neuron degeneration in ALS - prevention by glycoursodeoxycholic acid and signaling to microglia". Master's thesis, Faculdade de Ciências e Tecnologia, 2012. http://hdl.handle.net/10362/12438.

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Dissertação para obtenção do Grau de Mestre em Genética Molecular e Biomedicina
Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease that affects mainly motor neurons. Neuronal pathology involves glial cells, in particular microglia. However it is not known how these cells interact with motor neurons. This is particularly important because till now no therapy has shown efficacy in ALS treatment. Here, we aim (i) to evaluate the suitability of NSC-34, a hybrid cell line of neuroblastoma and motor neurons, as a model of ALS, (ii) to explore the reactivity of microglia to the neuronal released factors and (iii) to assess the efficacy of glycoursodeoxycholic acid (GUDCA), which already has shown beneficial effects in several neurodevelopmental and neurodegenerative diseases. For that, we used NSC-34 cells transfected with human superoxide dismutase 1 (hSOD1), either wild type or mutated in G93A and the microglial N9 cell line. We observed mitochondrial dysfunction, energy impairment, NO production and metalloproteinase-9 activation, with consequent apoptosis in NSC-34/hSOD1G93A cells after 4 days of differentiation, in comparison to NSC-34/hSOD1wt cells. In addition, we established GUDCA as an anti-apoptotic and anti-inflammatory agent, able to prevent all the above mentioned features. Finally, released neuronal factors induced N9 microglia apoptosis and decreased their phagocytic ability. Overall, our results emphasize NSC-34/hSOD1G93A cells as a good ALS model, highlight GUDCA as having beneficial effects and point to microglia neuroprotective failure as a determinant mechanism of ALS pathogenesis.
Fundação para a Ciência e Tecnologia - PTDC/SAU-FAR/118787/2010, entitled “Are microglia a new potential target in amyotrophic lateral sclerosis (ALS)?” to DB and PEst- OE/SAU/UI4013/2011 to iMed.UL
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44

Eckels, M. A., Phillip R. Scheuerman, D. M. Johnson y G. R. Lanza. "Effects of Highway Construction on Water Quality and Its Influence on Cadmium Toxicity to Mayfly Larvae". Digital Commons @ East Tennessee State University, 1993. https://dc.etsu.edu/etsu-works/2898.

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45

Wångstrand, Håkan. "Effects of nitrogen fertilization on the cadmium concentration in winter wheat grain : field studies on cadmium and nitrogen uptake and distribution in shoots as related to stage of development /". Uppsala : Dept. of Soil Sciences, Swedish University of Agricultural Sciences, 2005. http://epsilon.slu.se/9982614.pdf.

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46

Bricker, Timothy J. "Metal removal from contaminated soil by hyper-accumulating plants : effects of repeated croppings". Virtual Press, 2000. http://liblink.bsu.edu/uhtbin/catkey/1172471.

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Phytoremediation, i.e., the use of plants to clean up contaminated soil, may serve as a feasible alternative if a high-biomass crop can be found that accumulates metals to a high.degree. Two plant species, corn (Zea mays) and Indian mustard (Brassica juncea), were grown in soil from a Superfund site contaminated with Pb and Cd (PbTota, = 65,200 mg/kg and CdTotI = 52 mglkg) over two croppings. Soil treatments consisted of composted sewage sludge (CSS), ethylenediaminetetraacetic acid (EDTA), and sodium citrate at two concentrations. In most cases, the EDTA and citrate treatments were superior in terms of extracting soil Pb into root tissue, and translocation of Pb into aboveground biomass. The CSS treatment typically resulted in the lowest Pb removal efficiencies. The high pH (7.4) and high exchange capacity of the CSS may have immobilized soil Pb. Soil Cd was generally more mobile than soil Pb. The EDTA2 treatment was most effective in removing soil Pb into roots, and translocation to shoots. Lead remaining in the soil after two croppings was mainly associated with the carbonate, organic, and residual fractions, which represent the less bioavailable form of this metal.
Department of Natural Resources and Environmental Management
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47

Nilsson, Sommar Johan. "Prospective and longitudinal human studies of lead and cadmium exposure and the kidney". Doctoral thesis, Umeå universitet, Yrkes- och miljömedicin, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-67832.

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Cadmium and lead accumulate in humans and can have toxic effects. Exposure to cadmium is well known to cause kidney damage. Cadmium binds to metallothioneins, proteins that play a role in cadmium transport. Lead exposure’s main effect is on the central nervous system, but associations with kidney disease have also been found, although it is unknown if the latter is a causal association. The main source of both metals within the non-smoking population is from the diet. This thesis aims to 1) compare the biomarkers lead and cadmium concentration in whole-blood, plasma and urine with regard to their ability to discriminate between individuals with different mean concentrations, and to describe the effect of urinary dilution, 2) estimate the association between end-stage renal disease and blood concentrations of cadmium, lead and mercury, using prospectively collected samples for exposure evaluation, 3) use longitudinal data on kidney function makers to evaluate kidney recovery after a substantial decrease in cadmium exposure, and 4) assess the influence of metallothionein polymorphisms (MT1A rs11076161, MT2A rs10636 and MT2A rs28366003) on cadmium-associated kidney toxicity and recovery due to a reduction in Cd exposure. Repeated sampling of whole-blood, plasma and urine was conducted on 48 occupationally lead-exposed men and 20 individuals under normal environmental lead exposure, for estimation of the day-to-day and between individual-variation. Prospective samples were obtained for 118 cases that later in life developed end-stage renal disease, and 378 matched controls. Erythrocyte cadmium, lead, and mercury concentrations were determined and the risk of developing end-stage renal disease associated with metal concentrations was estimated. For evaluation of kidney recovery after a reduction in cadmium exposure and to test for gene-environment interactions, follow-up data on N-acetyl-β‑d-glucosaminidase, β2‑microglobulin, albumin, and gene polymorphisms were obtained for 412 individuals within the Chinese population and the relation to blood and urinary cadmium was assessed. The concentration of lead in blood was found to be the biomarker with the largest fraction of the total variance attributable to between-individual variation, and was therefore the biomarker with the best ability to discriminate between individuals with different mean concentrations, both for individuals under occupational and normal environmental exposure (91 and 95%, respectively). Adjusting for urinary dilution had a great effect on the fraction of the total variance attributable to between-individual variation among individuals with normal lead exposure but only a minor effect among those who were occupationally exposed. Variance analysis showed that blood concentrations were also the best discriminating biomarker for cadmium. Erythrocyte lead was, in a univariate model, associated with an increased risk of developing end-stage renal disease [odds ratio (OR) = 1.54 for an interquartile range increase, with a 95% confidence interval (CI) = 1.18-2.00], while erythrocyte mercury was negatively associated (OR = 0.75 for an interquartile range increase, with a 95% CI = 0.56-0.99). For erythrocyte cadmium, the OR was 1.15 with a 95% CI of 0.99-1.34. Associations with lead and cadmium were only seen among men. In the study on kidney recovery, the proportion of individuals with albumin level above the 95th percentile decreased between baseline and follow up, but no decrease was found for the tubular markers N-acetyl-β‑d-glucosaminidase and β2-microglobulin. Metallothionein polymorphisms modified cadmium-associated effects on N-acetyl-β‑d-glucosaminidase and β2-microglobulin levels but did not modify cadmium-associated change in any of the kidney function markers between baseline and follow up after a substantial decrease in exposure. Blood concentrations of lead and cadmium are the biomarkers with the best ability to discriminate between individuals with different mean concentrations. Adjustment for urinary dilution has great influence on the fraction of the total variance attributed to between individual variation among urine samples with low lead concentrations, but only a small influence on samples with high lead concentrations. This suggests a difference in excretion. The association between end-stage renal disease and low-level lead exposure, as assessed through prospective erythrocyte samples, gives reason for concern, although further studies are needed to determine causality. A cadmium-associated increase in albumin is reversible after a substantial reduction in exposure, but this is not the case for the observed tubular effects. The tubular kidney effects of cadmium might be modified by the MT1A rs11076161 polymorphism.
För att bedöma exponering för kadmium och bly mäts ofta deras koncentrationer i blod eller urin. Dessa studerades i longitudinella data för 48 blyarbetare och 20 individer med normal miljömässig exponering. Blod- och urinprover togs var annan till var tredje månad. Kadmium- och blykoncentrationer mättes sedan i helblod, plasma och urin. Koncentrationer av bly i blod var den biomarkör som hade den största andelen av den totala variationen som kunde förklaras av skillnader mellan individer, och var därför den biomarkör med den bästa förmågan att särskilja på individer med olika medelkoncentration, både för individer med yrkesexponering och normal miljömässig exponering (91 respektive 95% av variansen berodde på vilken individ blodprovet kom ifrån). Justering för urinens utspädning av bly i urin förbättrar oftast urins användbarhet som biomarkör. För bly stämde detta bara hos dem som inte var blyarbetare. Blodkoncentrationer var också den biomarkör med störst andel av den totala variation som kunde förklaras med skillnader mellan individer för kadmium. Kadmium och bly ackumuleras i njure respektive ben och kan ha toxikologiska effekter. Det är välkänt att höga exponeringsnivåer av kadmium orsakar njurskada och även vid lägre exponeringsnivåer har studier funnit samband med markörer för njurfunktion. Exponering för bly påverkar i första hand det centrala nervsystemet. Studier har dock funnit samband mellan koncentrationer av bly i blod och njurens glomerulära filtrationshastighet. Det är oklart både om dessa associationer, vid låga exponeringsnivåer, är viktiga för hälsan och om de verkligen beror på att kadmium och bly orsakar njurskada. För att studera end-stage renal disease användes prospektiva kohorter där personer lämnat blodprov för forskning: Västerbottens interventionsprogram med prover som tagits vid Västerbottens hälsoundersökningar, MONICA-undersökningar i Norr- och Västerbotten, mammografiundersökningarna i Västerbotten och Malmö kost cancer. Sammanlagt ingick över ett hundra tusen individer i dessa kohorter. Med hjälp av det Svenska njurregistret identifierades sedan 118 personer som senare i livet fått end-stage renal disease. Dessa jämfördes med 378 kontroller. För dessa 496 personer tinades blodprovet (närmare bestämt röda blodkroppar) upp och analyserades för kadmium och bly. För att undersöka njurens förmåga till återhämtning studerades tre områden i Kina varav ett tidigare varit kraftigt kadmiumexponerat. Erytrocytkoncentrationer av bly var, utan att ta hänsyn till några andra variabler, associerat med en ökad risk för att utveckla end-stage renal disease (med oddskvoten 1.54 för en interquartile range ökning av erytrocytbly, med ett 95% konfidensintervall 1.18-2.00). Sambanden kvarstod också efter att ha tagit hänsyn till övriga variabler. För erytrocytkadmium var oddskvoten 1.15 med 95% konfidensintervall 0.99-1.34, och sambandet försvagades när hänsyn togs till andra variabler. Associationerna sågs bland män men inte bland kvinnor. Eftersom kadmium vid höga nivåer orsakar njurskada är det också av intresse att studera om påverkan på njuren går över om exponeringen minskas. Totalt följdes 412 individer upp med mätningar av markörer för njurfunktion och kadmiumkoncentrationer i blod och urin. Första undersökningen gjordes 1998, då man just hade slutat äta kadmiumförorenat ris. En andra undersökning gjordes 2006. Andelen individer med avvikande albuminvärde i urin var lägre vid uppföljningen jämfört med vid baslinjen, men ingen minskning sågs för markörer för tubulär förmåga att återta proteiner. Åttioprocent av kadmium i celler är bundet till proteinet metallotheonin, vilket skyddar mot cellskada, men har också en roll i transporten av kadmium från levern till njurarna. En tidigare studie har visat att njurens känslighet för kadmiumexponering var associerad med genetiska skillnader i detta protein. För att studera genetiska associationer studerades de 412 personerna i den kinesiska studien [då också individernas genotyper av metallotheonin-polymorfierna MT1A rs11076161 (G/A), MT2A rs10636 (G/C) och MT2A rs28366003 (A/G) bestämdes]. Genetiken spelade roll för sambandet mellan förmåga att återta proteiner och kadmium men påverkade inte förändring av njurfunktion efter att man slutat äta kadmiumförorenat ris. Kadmium- och blykoncentrationer i blod är de biomarkörer, av koncentrationer i blod, plasma och urin, med den bästa förmågan att skilja på individer med olika medelkoncentrationer. Justering för urinutspädning påverkade andelen av den totala variationen som kunde förklaras av skillnader mellan individer i stor utsträckning för individer med normal miljömässig exponering men inte bland yrkesexponerade, vilket tyder på en skillnad i hur utsöndringen går till. Associationen mellan end-stage renal disease och låg exponering för bly, uppmätta i prospektiva erytrocytprover, ger orsak till oro, men ytterligare studier behövs för att kunna utvärdera om detta är ett kausalt samband. En kadmiumrelaterad skada av den glomerulära filtrationen är reversibel efter en kraftig reducering i exponering, men detta är inte fallet för tubulär skada. De tubulära njureffekterna av kadmiumexponering kan påverkas av metallotheonin-polymorfier.
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48

Barbosa, Marta Isabel da Silva Rodrigues. "Dissecting cross-talk between microglia and motoneurons in ALS: signaling events and soluble factors". Master's thesis, Faculdade de Ciências e Tecnologia, 2013. http://hdl.handle.net/10362/10925.

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Dissertação para obtenção do Grau de Mestre em Genética Molecular e Biomedicina
Convergence of pathways in motoneuron (MN) injury include microglia in the initiation and progression of Amyotrophic Lateral Sclerosis (ALS). Neuroinflammation is a pathological hallmark of ALS and microglia may acquire neurotoxic or neuroprotective properties in response to misfolded superoxide dismutase-1 (SOD1) or other molecules produced by the injured MN. We assessed: (i) the role of microglia in preventing/restoring MN dysfunction using a mixed culture of NSC-34 MN-like cells (mutated in G93A) and of N9 microglia cells, added at 0 or 2 days-invitro(M0, M2) and cultured till 4 and 7 days-in-vitro; (ii) neurodegenerative network in organotypic cultures from lumbar segments of spinal cord (SC) obtained from the ALS mice model TgSOD1-G93A at 7 day-old and aged for 10 days-in-vitro, as well as the response to lipopolysaccharide (LPS, 1μg/mL) immunostimulation. Western blot assays for SOD1, high-mobility-group-box-protein-1 (HMGB1) and toll-like receptor-4 (TLR-4), and fluorimetric/colorimetric assays for ATP, glutamate and nitric oxide (NO), were used. Microglia (M0/M2) decreased the accumulation of human/mouse mutated SOD1 (P<0.01). In addition, elevation of glutamate efflux (P<0.01), and reduction of extracellular ATP (P<0.01), MMP-2(P<0.05) and MMP-9 (P<0.01) was observed by M2 at 7 days-in-vitro. Reduction of NO (P<0.05) and MMP-2 (P<0.01) was obtained with M0. HMGB1 increased by M0 and decreased by M2, suggesting HMGB1 release from the cell. Accumulation of SOD1 was verified in SC organotypic cultures, but no changes in ATP or NO were obtained, although a slight decrease in ATP by LPS was verified. Downregulation of TLR-4 by LPS may indicate the exhaustion of the inflammatory response mechanisms in the aged SC culture. Together, these results suggest that microglia by inhibiting MMP activation and HMGB1 cytoplasmic translocation in the ALS model are key in modulating MN degeneration and should be considered as therapeutic targets in ALS.
supported by FEDER (COMPETE Programme) and by National funds (Fundação para a Ciência e a Tecnologia – FCT, Portugal) with the projects PTDC/SAU-FAR/118787/2010 to D.B. and PEst-OE/SAU/UI4013/2011 and 2012 to iMed.UL
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49

Polykretis, Panagis. "Development and application of methods to investigate proteins in mammalian cells by NMR". Doctoral thesis, 2018. http://hdl.handle.net/2158/1138481.

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Tsai, Meng-Ling y 蔡孟苓. "Study on the Effects of Cadmium in Activity and Structure of Cu,Zn-SOD". Thesis, 2001. http://ndltd.ncl.edu.tw/handle/04686307416009950588.

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碩士
台北醫學院
醫學研究所
89
Of Amyotrophic Lateral Sclerosis (ALS) , a progressive neurodegenerative disorder cases, 10% are familial and 90% are sporadic. The mutations found in the Cu,Zn-SOD (SOD1) are the causes of 20% of familial ALS. Most mutations cause the decrease of the SOD enzyme activity and some of them are due to the loss of zinc affinity or alteration of the zinc binding site. Zinc and cadmium constitute group IIB of the periodic table of elements and are uniformly divalent. They share certain common biological responses. In order to investigate the possible causes of heavy metal interactions, we have constructed, expressed, and purified human Cu,Zn-SOD in E. coli with equal amounts of copper and zinc but different concentrations of cadmium in LB broth. First, SDS-PAGE and western blot analysis illustrated a 23kDa monomer. Second, the more cadmium added, the lower enzyme activities remained. Third, by atomic absorption spectrophotometer, we found that the more cadmium added, the more cadmium atoms and the less zinc atoms detected in purified Cu,Zn-SOD. The results of observation and estimation of the purified Cu,Zn-SOD protein structure from native gel and circular dichroism indicate that the structure of apo-SOD, without any metals, is much different from Cu,Zn-SOD and Cu,Zn-SOD with 500 nM cadmium. Besides, secondary structure of Cu,Zn-SOD with 500 nM cadmium is much close to apo-SOD. On the other hand, we have confirmed that cadmium is a strong inducer of metallothionein as previous studies reported. These results indicated that cadmium might effect zinc contents of Cu,Zn-SOD owing to its strong induction of metallothioneins which also bind zinc. Therefore, cadmium might play a role in sporadic ALS. These findings may offer some directions to study pathogenic mechanism.
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