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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
321

Comparison of a Novel Cell-based Reporter Assay and a Competitive Binding ELISA for the Detection of Thyrotropin-Receptor (TSHR) Autoantibodies (TRAb) in Graves’ Disease Patients

Hata, Misako 16 April 2010 (has links)
No description available.
322

Molecular Characterization of Light-Absorbing Components in Atmospheric Organic Aerosol

Kyla Sue Anne Siemens (18364617) 17 April 2024 (has links)
<p dir="ltr">Atmospheric organic aerosols (OA) have diverse compositions and undergo complex reactions and transformations within the atmosphere, leading to profound impacts on air quality, climate, and atmospheric chemistry. In particular, these aerosols play an important role in Earth's effective radiative forcing (ERF) through interactions with solar radiation, absorbing and scattering sunlight and terrestrial radiation. These interactions result in a warming and cooling effect on the climate, respectively. This dissertation seeks to unravel the intricate molecular characteristics of atmospheric OA, focusing specifically on its light-absorbing components, known as ‘Brown Carbon’ (BrC), and aims to comprehend its dynamic interplay within the atmosphere. The research employs state-of-the-art multi-modal mass spectrometry techniques to investigate atmospheric OA derived from the combustion of fossil fuels and biomass burning. Through a combination of controlled laboratory experiments and real-world sample analyses, these works provide molecular-level insights crucial for source apportionment and predictive modeling of OA fate. Chapter 2 details the instrumentation and data analysis methods, laying a robust foundation for subsequent chapters.</p><p dir="ltr">Chapter 3 delves into the investigation of smoldering-phase biomass burning organic aerosols (BBOA) and introduces an innovative fractionation method for high-level molecular characterization, targeted to streamline source apportionment of BBOA. This chapter also presents an extensive assessment of particle-to-gas partitioning of BBOA, providing valuable information for modeling atmospheric lifetimes and fate. In Chapter 4, a comparative analysis of BBOA from wild and agricultural fires is conducted, employing advanced molecular characterization techniques. Chapter 5 showcases the synergistic use of multi-modal mass spectrometry techniques to probe the chemical evolution of individual BBOA components. Finally, Chapter 6 examines the molecular analysis of secondary OA (SOA) generated from the photooxidation of a fossil-fuel proxy.</p><p dir="ltr">The comprehensive molecular-level studies presented contribute essential insights for climate modeling, aiding in resolving uncertainties associated with OA's impact on global ERF. The research not only challenges existing analytical methods but also introduces novel approaches for obtaining relevant information about atmospheric OA components. Overall, this work advances our understanding of the intricate dynamics of atmospheric aerosols, facilitating more accurate climate predictions and addressing uncertainties surrounding their net radiative impact.</p>
323

Biotestsystem mit Bodenalgen zur ökotoxikologischen Bewertung von Schwermetallen und Pflanzenschutzmitteln am Beispiel von Cadmium und Isoproturon

Burhenne, Matthias 09 May 2000 (has links)
Biotests sind für die toxikologische Bewertung von Chemikalien, Pflanzenschutzmitteln und schadstoffbelasteten Gewässern oder Böden von besonderer Bedeutung, da sie Auskünfte über die biologische Wirksamkeit eines Stoffes auf Organismen geben. Bislang gibt es für die ökotoxikologische Bewertung, insbesondere von Chemikalien und Pflanzenschutzmitteln, für die autotrophe Organismenebene neben verschiedenen Biotests mit höheren Pflanzen den DIN 28 692 Biotest "Wachstumshemmtest mit den Süßwasseralgen Scenedesmus subspicatus und Selenastrum capricornutum", der auch als OECD 201 Biotest "Algal, Growth Inhibition Test" vorliegt. Dieser aquatische Biotest wird nur mit einer Süßwasseralgenart durchgeführt und trotzdem zunehmend für die Bewertung von belasteten Böden und Sedimenten eingesetzt. Untersuchungen über aquatische Biotests, die Bodenalgen als Testorganismen nutzen, oder Boden-Biotests mit Bodenalgen gibt es nur vereinzelt. Ein Biotestsystem, das sowohl aus einem aquatischen als auch aus einem terrestrischen Biotest besteht und mehrere Bodenalgenarten als Testorganismen nutzt, existiert bisher nicht. Dieses wurde in vorliegender Arbeit entwickelt und an dem Schwermetall Cadmium als Cadmiumchlorid und dem Herbizid Arelon, Wirkstoff Isoproturon erprobt. Um Bodenalgen, die keine Resistenzen oder Toleranzen gegenüber Schadstoffen aufweisen, als Testorganismen nutzen zu können, wurden aus unbelasteten Böden Algen isoliert, Klonkulturen erstellt und die Arten bestimmt. Dies führte zu einer Sammlung mit 35 Algenarten. Aus den in die Bodenalgensammlung aufgenommenen Arten wurden Xanthonema tribonematoides, Stichococcus bacillaris, Klebsormidium flaccidum, Xanthonema montanum und Chlamydomonas noctigama für das Testsystem ausgewählt. Zusätzlich zu diesen wurde die Süßwasseralge Scenedesmus subspicatus als Referenzalge ausgewählt. Mit diesen Algen wurde der Gel-Biotest, bestehend aus einem flüssigen gelartigen Medium, das die Kontaminationspfade im Wasser nachbildet, und ein Boden-Biotest mit einem naturnahen sorptionsschwachen Boden entwickelt, der die Kontaminationspfade über Gas-, Wasser- und Festphase im Boden nachbildet. Bei der Erprobung dieses Biotestsystems mit Cadmiumchlorid und Isoproturon zeigte sich, daß Bodenalgen gegenüber Cadmiumchlorid im Gel-Biotest eine geringe bis mittlere Sensibilität aufwiesen. Im Boden-Biotest lag eine sehr geringe Sensibilität vor, wie dies auch bei anderen Bodenorganismengruppen in Biotests festgestellt wurde. Dies kann mit der Sorption der Cadmiumionen im Boden erklärt werden und dem damit geringen für die Organismen bioverfügbaren Cadmiumionenanteil. Für Isoproturon lag sowohl im Gel- als auch im Boden-Biotest eine hohe Sensibilität der Bodenalgen vor. Erstaunlich war, daß die Sensibilität in beiden Biotests nahezu identisch war, obwohl Isoproturon in sorptionsschwachen Böden zu ca. 30 % adsorbiert wird. Im Vergleich zur Sensibilität von Scenedesmus subspicatus waren die Bodenalgen bei Cadmiumchlorid bis auf zwei Ausnahmen um den Faktor 5 bis 10 unsensibler. Die Bodenalge Klebsormidium flaccidum besaß eine vergleichbare Sensibilität und Xanthonema montanum war um den Faktor 20 unsensibler. Für Isoproturon konnten keine Unterschiede in der Sensibilität zwischen Scenedesmus subspicatus und den geprüften Bodenalgen ermittelt werden, außer bei Stichococcus bacillaris, die um den Faktor 5 unempfindlicher war. Das entwickelte miniaturisierte Biotestsystem eignet sich dazu, differenzierte Aussagen über das ökotoxische Potential von Stoffen auf Bodenalgen und der Süßwasseralge Scenedesmus subspicatus zu erhalten. Durch den Einsatz von zwei unterschiedlichen Testsubstraten (Flüssigmedium und naturnaher Boden) werden der Einfluß dieser Substrate sowie die daraus resultierenden Kontaminationspfade der Teststoffe und ihre ökotoxikologische Wirkung auf Algen feststellbar und vergleichbar. Ein Normenentwurf des Biotestsystems wurde inzwischen in das "Technical Committee 190 - Soil Quality" der International Standards Organization (ISO) eingereicht. / Biotests are an important device to assess the toxicity of chemicals, pesticides, polluted water, and soils because they can provide direct information about the influence of a compound on the organism level. Besides various biotests using higher plants there is only the DIN 28 692 biotest "Growth-inhibition test using fresh water algae Scenedesmus subspicatus and Selenastrum capricornutum" (DIN 28 692) also known as the OECD 201 biotest "Algal, Growth Inhibition Test" which is currently available for an ecotoxicological assessment of chemicals such as pesticides on the autotrophic organism level. This aquatic biotest is based on a single specie of fresh water algae and is increasingly applied to evaluate polluted soils and sediments. There is almost no information on aquatic biotests which are using soil algae as test organisms instead. A more comprehensive biotest system which actually combines aquatic and terrestric biotests using several soil algae species as test organisms has not been reported, yet. Thus, a biotest system was developed and subsequently evaluated by using cadmium (cadmium chloride) as a heavy metal, and the herbicide arelon containing isoproturon as the active ingredient. Soil algae were isolated from unpolluted soil in order to obtain test organisms which are not resistant or tolerant to pollutants. The algae isolates were then cultivated, and subsequently identified. A total of 35 algae species was collected. Algae species used in the biotest system were Xanthonema tribonematoides, Stichococcus bacillaris, Klebsormidium flaccidum, Xanthonema montanum, Chlamydomonas noctigama. In addition, the fresh water specie Scenedesmus subspicatus served as a reference algae. Based on these different algae species a gel biotest using liquid gel medium was developed to investigate the contamination path via water, and also a soil biotest with a pre-treated soil of low sorption capacity was deviced to simulate the contamination path through gas, water, and solid phase. The evaluation of the biotest system using cadmium chloride and isoproturon did reveal that soil algae have had only low to medium sensitivity to cadmium chloride in the gel biotest. Algae sensitivity in the soil biotest was very low which was in accordance with data from other biotests using different soil organisms. The weak response of the algae was most likely caused by the sorption of the cadmium ions to the soil matrix what may have decreased the bioavailability of cadmium. In comparison, soil algae were very sensitive to isoproturon in both, the gel biotest and the soil biotest. Both biotests indicated almost identical sensitivities of the tested soil algae which was surprising since 30 % of the isoproturon was sorbed even in soils with a low sorption capacity. Soil algae when compared to the water algae Scenedesmus subspicatus were generally 5 to 10-fold less sensitive to cadmium chloride. Only Klebsormidium flaccidum has proved to have a similar sensitivity as Scenedesmus subspicatus had, whereas Xanthonema montanum was about 20-fold less sensitive. With isoproturon, however, no differences in sensitivity could be seen between Scenedesmus subspicatus and the tested soil algae, except Stichococcus bacillaris which was about 5-fold less sensitive. The biotest system as developed in this study has shown to be suitable for obtaining valuable information about ecotoxicological effects of chemicals on soil and water algae. Since the biotest system consists of two different test media (liquid gel and soil) it is possible to determine ecotoxicological effects on algae in both, water and soil. A first draft of the developed biotest system has been submitted to the "Technical Committee 190 - Soil Quality" of the International Standards Organization (ISO) for review.
324

Sicherheitsforschung und Monitoringmethoden zum Anbau von Bt-Mais: Expression, Nachweis und Wirkung von rekombinantem Cry1Ab in heterologen Expressionssystemen / Biosafety research and monitoring methods of Bt-corn: Expression, detection and effect of recombinant Cry1Ab in heterologous expression systems

Nguyen, Thu Hang 08 November 2004 (has links)
No description available.
325

Incidence of Clostridium botulinum Spores in Honey and Infant Food Samples Collected from Vietnam and Germany / Vorkommen von Clostridium-botulinum-Sporen in Honig- und Säuglingsnahrungsproben aus Vietnam und Deutschland

Vu, Thi Lam An 02 November 2006 (has links)
No description available.
326

Avaliação da potência do hormônio da paratireóide humano recombinante por bioensaio, métodos cromatográficos e eletroforético / Recombinant human parathyroid hormone potency evaluation by bioassay, chromatographic and electrophoretic methods

Maldaner, Fernanda Pavani Stamm 24 May 2017 (has links)
Fundação de Amparo à Pesquisa do Estado do Rio Grande do Sul - FAPERGS / The human parathyroid hormone (hPTH) is a polypeptide secreted by the parathyroid glands that is essential for the maintenance of the calcium ion homeostasis in the blood. The recombinant DNA technology has enabled the expression of hPTH gene in Escherichia coli, and thus the large-scale production of recombinant human parathyroid hormone (rhPTH 1-34), teriparatide, which contain the active amino-terminal fragment of the full length hPTH. The rhPTH is clinically used to treat osteoporosis at high risk of fractures in postmenopausal women, men with osteoporosis primary or hypogonadal and adults with glucocorticoid-induced osteoporosis (GIO). Cappilary zone electrophoresis (CZE) method was developed and validated for the assessment of rhPTH in biopharmaceutical formulations. The analysis for CZE method was performed on a fused-silica capillary (effective length, 40 cm; 50 μm i.d.), using electrolyte solution consisted of 50 mM dihydrogen phosphate solution at pH 3.0. The capillary was maintained at 25º C, the applied voltage was 20 kV. Injections were performed using a pressure mode at 50 mbar for 45 s, with detection by photodiode array detector set at 200 nm. Separation was obtained with a migration time of 5.3 min, and was linear over the concentration range of 0.25-250 μg mL-1 (r2 = 0.9992). The limits of detection and quantitation were 0.12 and 0.40 μg/mL, respectively. Specificity and stability-indicating capability were established in degradation studies, which also showed that there was no interference of the excipients. The accuracy was 100.28% with bias lower than 0.85%. Moreover, the in vitro cytotoxicity test of acidic, photolytic and thermal degradated forms showed significant differences (p<0.05) compared to intact molecule. The cell proliferation and alkaline phosphatase activity bioassays in UMR-106 cells were developed and applied to assess the biological activity of rhPTH in biopharmaceutical formulations The results of content/potency were correlated to those of the validated reversed-phase liquid chromatography (RP-LC), size-exclusion liquid chromatography (SE-LC) and CZE methods, showing significant correlation (p> 0.05) Thus, the application of the validated physico-chemical methods together with in vitro bioassays, was suggested to improve quality control of rhPTH biotechnology-derived product and to support studies of biosimilars. / O hormônio da paratireóide humano (hPTH) é um polipeptídeo produzido e secretado pelas glândulas paratireóides, e é fundamental para a manutenção da homeostase dos íons cálcio no sangue. A tecnologia do DNA recombinante possibilitou a expressão do gene do hPTH em Escherichia coli, e a produção em grande escala do hormônio da paratireóide humano recombinante (rhPTH 1-34), também denominado Teriparatida, o qual apresenta a sequência de aminoácidos responsável pela porção biologicamente ativa do paratôrmonio natural. O rhPTH é clinicamente indicado para o tratamento da osteoporose de alto risco de fraturas em mulheres pós-menopausa, de homens com osteoporose primária ou hipogonadal, e da osteoporose associada à terapia sistêmica com glicocorticóides. Neste trabalho foi desenvolvido e validado método por eletroforese capilar de zona (ECZ) para a avaliação de rhPTH em produtos biofarmacêuticos. No método por ECZ, utilizou-se capilar de sílica fundida (40 cm de comprimento efetivo x 50 μm d.i.) e solução eletrolítica composta de fosfato de sódio dihidrogenado 50 mM, pH 3,0. O capilar foi mantido a temperatura de 25ºC, e a tensão aplicada foi de 20 kV. O tempo de injeção foi de 45 s, com pressão de 50 mBar, e detecção por arranjo de diodos (DAD), em 200 nm. A separação eletroforética foi obtida com tempo de migração de 5,3 min, sendo linear na faixa de concentração de 0,25-250 μg/mL (r2 = 0,9992). Os limites de detecção e quantificação foram de 0,12 e 0,40 μg/mL, respectivamente. A especificidade foi avaliada através de análises com os excipientes da formulação biofarmacêutica e estudos de degradação, demonstrando a seletividade do método. A exatidão foi 100,28% com bias inferior a 0,85%. Além disso, realizou-se o teste de citotoxicidade in vitro das formas degradadas, apresentando, para as amostras submetidas às condições ácida, fotolítica e térmica, diferença significativa (p< 0,05) em relação à molécula íntegra. Os bioensaios de proliferação celular e da atividade da fosfatase alcalina em células UMR-106 foram desenvolvidos e aplicados para avaliação da atividade biológica de rhPTH em formulações biofarmacêuticas. Os resultados de teor/potência foram correlacionados com os métodos já validados por cromatografia líquida em fase reversa (CL-FR), cromatografia líquida por exclusão molecular (CL-EM) e ECZ, apresentando correlação significativa (p> 0,05). Assim, sugere-se que o métodos físico-químicos validados sejam aplicados paralelamente aos bioensaios in vitro para aprimorar o controle da qualidade do produto biotecnológico de rhPTH, e para avaliação da biossimilaridade de rhPTH.
327

Expressão de tireotrofina humana em células de embrião de rim humano (HEK293) / Human tryrotropin expression in human embrionic kidney cells (HEK293)

SANTANA, PATRICIA M. 22 December 2016 (has links)
Submitted by Marco Antonio Oliveira da Silva (maosilva@ipen.br) on 2016-12-22T16:39:39Z No. of bitstreams: 0 / Made available in DSpace on 2016-12-22T16:39:39Z (GMT). No. of bitstreams: 0 / Neste trabalho foi transfectada uma linhagem de células embrionárias de rim humano (HEK293) com os genes das subunidades &alpha; e &beta; da tireotrofina humana (hTSH), hormônio glicoproteico secretado pela hipófise. Após 5 dias de cultivo obteve-se uma concentração de hTSH no meio condicionado de 0,95&mu;g/mL. O material foi concentrado e purificado utilizando uma estratégia envolvendo duas etapas, uma cromatografia de troca catiônica e uma cromatografia líquida de alta eficiência (HPLC) de fase reversa, que permitiu uma recuperação de 55% e uma pureza >90%. O produto purificado (hTSH-HEK) foi analisado e comparado a uma preparação comercial obtida em células CHO (hTSH-CHO) e a uma preparação hipofisária (hTSH-Pit). A identidade e a pureza do hTSH-HEK foram avaliadas por métodos físicoquímicos e imunológico (espectrometria de massa MALDI-TOF, HPLC de exclusão molecular e de fase reversa, SDS-PAGE e ensaio imunoradiométrico). A porção glicídica do hTSH-HEK foi avaliada pela análise do perfil dos N-glicanos e o comportamento biológico deste hormônio foi avaliado por bioensaio in vivo e estudo farmacocinético. As 3 preparações apresentaram pureza equivalente (97%) e a massa molecular relativa do hTSH-HEK foi 2,1% menor do que a do hTSH-CHO e 2,7% maior do que a do hTSH-Pit. A maior hidrofobicidade relativa, avaliada por RP-HPLC, foi a do hTSH-HEK. Os N-glicanos identificados no hTSH-HEK foram do tipo complexo, apresentando predominantemente estruturas tri-antenárias, enquanto no hTSH-CHO e no hTSH-Pit as estruturas bi-antenárias foram predominantes. Foram detectadas diferenças significativas relacionadas à composição dos carboidratos para estas preparações, um teor muito menor de ácido siálico e muito maior de fucose foram observados no hTSHHEK. Foi confirmada a atividade biológica das 3 preparações, sendo a bioatividade do hTSHHEK 39% e 16% inferior à do hTSH-CHO e hTSH-Pit, respectivamente. A meia-vida circulatória do hTSH-HEK foi menor (1,5 X) que a do hTSH-CHO e a do hTSH-Pit (1,2 X). De acordo com esses resultados o hTSH-HEK pode ser considerado uma alternativa viável para aplicações clínicas especialmente por sua origem humana e composição de carboidratos. / Dissertação (Mestrado em Tecnologia Nuclear) / IPEN/D / Instituto de Pesquisas Energéticas e Nucleares - IPEN-CNEN/SP
328

Advances in Gas Chromatography and Vacuum UV Spectroscopy: Applications to Fire Debris Analysis & Drugs of Abuse

Zackery Ray Roberson (9708611) 07 January 2021 (has links)
In forensic chemistry, a quicker and more accurate analysis of a sample is always being pursued. Speedy analyses allow the analyst to provide quick turn-around times and potentially decrease back-logs that are known to be a problem in the field. Accurate analyses are paramount with the futures and lives of the accused potentially on the line. One of the most common methods of analysis in forensic chemistry laboratories is gas chromatography, chosen for the relative speed and efficiency afforded by this method. Two major routes were attempted to further improve on gas chromatography applications in forensic chemistry.<br> The first route was to decrease separation times for analysis of ignitable liquid residues by using micro-bore wall coated open-tubular columns. Micro-bore columns are much shorter and have higher separation efficiencies than the standard columns used in forensic chemistry, allowing for faster analysis times while maintaining the expected peak separation. Typical separation times for fire debris samples are between thirty minutes and one hour, the micro-bore columns were able to achieve equivalent performance in three minutes. The reduction in analysis time was demonstrated by analysis of ignitable liquid residues from simulated fire debris exemplars.<br> The second route looked at a relatively new detector for gas chromatography known as a vacuum ultraviolet (VUV) spectrophotometer. The VUV detector uses traditional UV and far-ultraviolet light to probe the pi and sigma bonds of the gas phase analytes as well as Rydberg traditions to produce spectra that are nearly unique to a compound. Thus far, the only spectra that were not discernable were from enantiomers, otherwise even diastereomers have been differentiated. The specificity attained with the VUV detector has achieved differentiation of compounds that mass spectrometry, the most common detection method for chromatography in forensic chemistry labs, has difficulty distinguishing. This specificity has been demonstrated herein by analyzing various classes of drugs of abuse and applicability to “real world” samples has been demonstrated by analysis of de-identified seized samples.<br>
329

PhD Dissertation-Chemistry-Aayush-2023

Aayush Aayush (15354604) 26 April 2023 (has links)
<p> </p> <p>Learning about ‘behavior’ has always been at the heart of my research endeavors. While my undergraduate work in evolution and ecology exposed me to the science behind why a behavior exists, in my graduate work, I intended to explore how to use something’s behavior to widen its applicability. In this thesis, <em>I will present three works that utilize some of the fundamental</em></p> <p><em>behaviors (i.e., properties) of elastin-like polypeptides (ELP) to improve existing protein purification methods or explore their applicability in bladder cancer imaging and immunotherapy. </em></p> <p>Bladder cancer has high recurrence rates (60-70 % annually) that necessitate multiple follow-up therapies making it one of the costliest cancers per patient. In this work, we have attempted to address two leading causes of the recurrence. First is a low sensitivity (62-84 %) and variable specificity (43-95 %) of white light cystoscopy used to diagnose and remove tumors. We aimed to address the heart of this problem, i.e., the non-specific mode of detection using white light. Only the trained eyes can discern abnormal from normal-appearing tissues even then, leaving up to 45% of tumors unresected to colonize and spread. <em>We developed and characterized near infrared dye-peptide-ligand conjugates (NIR-ELP-ligand) that undergo receptor-mediated binding and internalization to human bladder cancer cells in vitro and tissues ex vivo.</em> By using a molecular target-based probe in combination with NIR imaging, we can aid in improving the detection limit via selective binding to the tumor and reduction in background autofluorescence.</p> <p>Bacillus-Calmette Guérin (BCG) instillation in the bladder is the gold-standard</p> <p>immunotherapy used after surgical removal of bladder tumors. This was approved as a response to the inefficiency of surgery alone in improving cancer status. It has succeeded by reducing the recurrence rate to 30-50 %. But it comes with the complications of putting a live mycobacterium</p> <p>in the human body and giving a patient a urinary tract infection right after surgical tumor resection. <em>Thus, we aimed to deliver nucleic acid as immunotherapeutic cargo in a selective manner to elicit robust anti-tumor immune responses while minimizing the side effects due to its carrier.</em> Towards</p> <p>this goal, we have developed a highly modular and adaptable ELP-ligand fusion protein-based nucleic acid delivery carrier targeted toward bladder cancer. Before developing targeted peptide-based cancer imaging and nucleic acid delivery modalities, we addressed the Achilles heel of peptide-based approaches. The peptide and protein industry suffers</p> <p>through complex, time-consuming, inconsistent, and low-yielding purification methods. <em>We have developed a scalable, facile, and reproducible protein purification method that delivers ELP and ELP fusion proteins free of host cell proteins and nucleic acids and has low lipopolysaccharide</em></p> <p><em>content in just 3 h starting from a bacterial pellet. </em>Thus, for a coherent narrative, the thesis is structured as follows:</p> <p>1. Introduction</p> <p>2. ELP as a protein purification tag: Development of a rapid purification method for ELPs and ELP fusion proteins.</p> <p>3. ELP as a cancer imaging agent: Development of NIR-ELP-Ligand imaging probe targeting bladder cancer.</p> <p>4. ELP as a drug delivery agent: Utilizing ELP-ligand fusion protein in the formulation of targeted nucleic acid delivery carrier to bladder cancer.</p>
330

Traits phénotypiques et développement de plantes exposées aux éléments traces; utilisation pour la phytoremédiation et l biosurveillance / Phenotypic traits and development of plants exposed to trace elements; use for phytoremediation and biomonitoring

Kolbas, Aliaksandr 05 October 2012 (has links)
Ce travail a pour objectif de tester des solutions viables et durables pour la phytoremédiation de sols contaminés en éléments traces. Il inclut à la fois des données sur l'évaluation initiale et résiduelle des risques (biomonitoring) et sur des solutions de phytomanagement à long terme utilisant des plantes et microorganismes associés, en particulier la phytoextraction aidée couplant l’épuisement du pool labile de contaminants du sol, la production de matière première végétale et la restauration de services écosystémiques. La phytotoxicité du Cu, le rôle améliorant des amendements organiques et minéraux et la tolérance des plantes ont été examinés utilisant des essais biologiques ainsi qu’une technique de dilution du sol. L'utilité d’une lignée de mutant de tournesol (Helianthus annuus) et d’une lignée parental de tabac (Nicotiana tabacum) pour le biomonitoring de sols contaminés en Cu a été investiguée. Les paramètres biochimiques qui sont en relation avec le statut antioxidant des plantes et leurs réponses moléculaires à l’excès de Cu ont en général montré une plus grande sensibilité que les traits morphologiques. Le tabac est plus tolérant au Cu que le tournesol. Des bactéries endophytes issues de différentes sources, notamment des graines d’une population métallicole d’une graminée (Agrostis capillaris) peuvent stimuler la croissance du tournesol et du tabac aux expositions en Cu modérément en excès. Pour ces plantes annuelles, accumulatrices secondaires du Cu et à phénotype d’exclusion, l'augmentation de la capacité de phytoextraction de Cu par les parties aériennes s’effectue principalement par l’accroissement de la biomasse aérienne, plutôt que par celui de sa concentration en Cu. Par conséquent, une attention a été prêtée aux pratiques agricoles dans les essais en parcelles sur site. Plusieurs options d’amélioration ont été examinées in situ: l'application d’amendements du sol, l'utilisation de lignées de mutants et de variants somaclonaux, la rotation de cultures et des cultivars, la bioaugmentation, la fertilisation, l’irrigation, etc. Deux lignées de mutants et des cultivars commerciaux de tournesol ainsi qu’une lignée parentale de tabac ont montré un fort potentiel pour la phytoextraction du Cu, accompagné d’une production significative de graines et/ou autre biomasse valorisable. Les solutions de restauration écologique basées sur la phytoextraction, utilisant des plantes annuelles accumulatrices secondaires de Cu permettraient (1) la décontamination progressive des sols contaminés en Cu au cours des rotations culturales, (2) un retour financier lié à la valorisation de la biomasse végétale, et (3) la restauration de services écosystémiques. / This work aimed at assessing sustainable phytoremediation options for trace element-contaminated soils. It includes both the assessment of initial and residual risks (biomonitoring) and long-term sustainable decontamination options using plants and associated microbes, especially aided phytoextraction with the secondary purposes of producing plant-based feedstock and restoring ecosystem services. Copper phytotoxicity, the improving role of soil conditioners, and plant tolerance were tested using a bioassay as well as a fading technique. The usefulness of a mutant line of sunflower (Helianthus annuus) and a motherline of tobacco (Nicotiana tabacum) for the biomonitoring of Cu-contaminated soils was investigated. Biochemical parameters in relation to antioxidant status of plants and molecular responses to Cu excess generally showed a greater sensitivity than morphologic ones. Tobacco has a higher Cu tolerance than sunflower. Endophytic bacteria from various sources, notably from the seeds of metallicolous populations of grasses (Agrostis capillaris) can promote the growth of sunflower and tobacco exposed to Cu excess. For annual Cu-secondary accumulator plants with an excluder phenotype, increase in shoot Cu removal occurred primarily through increase in shoot biomass, rather than in shoot Cu concentration. Therefore, attention in field trials was paid to agricultural practices. Various improving options were tested in situ: application of soil amendments, the use of mutant lines and somaclonal variation, cultivars and crop rotation, bioaugmentation, fertilization, irrigation, etc. Two mutant lines and some commercial cultivars of sunflower as well as the motherline of tobacco showed a high potential for Cu phytoextraction as well as for plant-based feedstock. Ecological restoration options for Cu-contaminated soils based on phytoextraction using annual Cu-secondary accumulator plants with a high shoot biomass would (1) result in the progressive decontamination of Cu-contaminated soils during crop rotations, (2) provide a financial return through biomass valorization, and (3) promote ecosystem services.

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