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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.
1

CORM-3 induces DNA damage through Ru(II) binding to DNA

Lyon, R.F., Southam, H.M., Trevitt, C.R., Liao, C., El-Khamisy, Sherif, Poole, R.K., Williamson, M.P. 01 November 2023 (has links)
Yes / When the 'CO-releasing molecule-3', CORM-3 (Ru(CO)3Cl(glycinate)), is dissolved in water it forms a range of ruthenium complexes. These are taken up by cells and bind to intracellular ligands, notably thiols such as cysteine and glutathione, where the Ru(II) reaches high intracellular concentrations. Here, we show that the Ru(II) ion also binds to DNA, at exposed guanosine N7 positions. It therefore has a similar cellular target to the anticancer drug cisplatin, but not identical, because Ru(II) shows no evidence of forming intramolecular crossbridges in the DNA. The reaction is slow, and with excess Ru, intermolecular DNA crossbridges are formed. The addition of CORM-3 to human colorectal cancer cells leads to strand breaks in the DNA, as assessed by the alkaline comet assay. DNA damage is inhibited by growth media containing amino acids, which bind to extracellular Ru and prevent its entry into cells. We conclude that the cytotoxicity of Ru(II) is different from that of platinum, making it a promising development target for cancer therapeutics.
2

Induction of Heme Oxygenase By a Carbon Monoxide-Releasing Molecule

Kulina, Robert Andrew 01 January 2007 (has links)
We have recently demonstrated that heme oxygenase is expressed in both healing wounds and in pressure ulcers. Heme oxygenase has been shown to have important cytoprotective functions in myocardial ischemia-reperfusion injury and organ allograft survival. The cytoprotective effects of heme oxygenase are multifactorial. Besides reducing levels of pro-oxidant heme, heme oxygenase products (bilirubin, carbon monoxide, and iron) have been demonstrated to possess anti-oxidant, anti-inflammatory, anti-apoptotic, and anti-proliferative properties. These properties make heme oxygenase an attractive therapeutic target for the prevention and treatment of chronic wounds. The purpose of this study was two-fold: evaluate the effects of carbon monoxide (CO) on the expression of heme oxygenase (HO-1) in dermal fibroblasts, and determine and begin to investigate the mechanisms responsible for CO-induction of HO-1. The ability of a second-generation carbon monoxide donating molecule-tricarbonyldichlororuthenium (II) dimer (CORM-2) to induce HO-1 protein expression in dermal fibroblasts was examined. Western blotting techniques were utilized to determine HO-1 expression. CORM-2 (100-300uM) induced maximum expression of HO-1. The maximum response to CORM-2 occurred between 12 and 20 hours. Inhibition of MAPK, PI3-K, JNK pathways showed no changes in HO-1 expression. Likewise inhibition of cGMP, a known pathway for CO, had no effect on protein expression suggesting that HO-1 expression by CORM-2 works by an alternate pathway. In conclusion the ability of CO, a product of heme degradation, to induce HO-1 in dermal fibroblasts may serve as a mechanism to amplify HO-1 expression in stressed tissues and may serve as the basis for a novel therapeutic approach for treating chronic wounds.
3

EFEITO DO NITROGÊNIO, CALCÁRIO E GESSO AGRÍCOLA EM ALGUNS ATRIBUTOS DE UM LATOSSOLO E NO DESENVOLVIMENTO DE GLADÍOLO / NITROGEN, LIMESTONE AND PHOSPHOGYPSUM EFFECTS IN SOME LATOSOL CHARACTERISTICS AND GLADIOLUS DEVELOPMENT

Gancedo, Marcelo 29 March 2007 (has links)
Made available in DSpace on 2016-02-26T12:59:37Z (GMT). No. of bitstreams: 1 MarceloGancedo.pdf: 341813 bytes, checksum: 7979c040bfdc034605ce046a6a950ead (MD5) Previous issue date: 2007-03-29 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / This work was developed in Gardening at UFMS (Universidade Federal de Mato Grosso do Sul) NCA (Núcleo Experimental de Ciências Agrárias), from September 2004 to February 2006 having the aim of valuating nitrogen, limestone and phosphogypsum over gladiolus development and over some chemical and physical characteristics of a dystroferric red latosol. Plants were valuated by leaf analysis, maximum high, spike and floral stem length, new corm diameter, dry and live mater form shoot area, and produced cormel number. Soil physical characteristics valuated the meaning clay, the meaning clay disperse in water, flocculation degree, aggregation and aggregation stableness. Soil chemical characteristics considered water and CaCl2 pH, macro and micronutrients meaning, exchangeable acidity, effective kation exchange capacity and base saturation. The experiment analysis was done in randomized blocks sub-subdivided in parcels, considering as parcel the nitrogen proportions (150, 300 kgha-1), as sub parcel the limestone proportion (0, 2000, 4000, 8000 kgha-1) and as sub-sub parcel phosphogypsum proportion (0, 500, 1000, 2000 kgha-1), in four repetitions. Nitrogen, limestone and Phosphogypsum proportions used caused no visual deficiencies detected in gladiolus. The smaller flowering time and the bigger live matter plants were gained without using limestone and / or phosphogypsum. Limestone between 6000 and 8000 kg.ha-1, contributed into ideal pH levels / Este trabalho foi desenvolvido na área de Jardinocultura do Núcleo Experimental de Ciências Agrárias da UFMS, durante o período de setembro de 2004 a fevereiro de 2006 tendo por objetivo a avaliação dos efeitos do nitrogênio, calcário e gesso agrícola sobre o desenvolvimento de Gladiolus grandiflorus e sobre alguns atributos físicos e químicos de um Latossolo Vermelho distroférrico. As plantas foram avaliadas por meio de análise foliar e quanto à altura máxima, comprimento da espiga e da haste floral, diâmetro do novo cormo, matéria fresca e seca da parte aérea e número de cormilhos produzidos. Como atributos físicos do solo foram avaliados o teor de argila, teor de argila dispersa em água, grau de floculação, agregação e estabilidade dos agregados. Os atributos químicos considerados foram o pH em água e em CaCl2, teores de macro e micronutrientes, acidez trocáveis, capacidade de troca de cátions efetiva e saturação de bases. O experimento foi analisado como inteiramente casualizado, em parcelas sub-subdivididas, sendo consideradas como parcelas as doses de nitrogênio (150 e 300 kg.ha-1), como subparcelas as doses de calcário (0, 2000, 4000 e 8000 kg.ha-1) e como sub-subparcelas as doses de gesso (0, 500, 1000 e 2000 kg.ha-1), com quatro repetições. As doses de nitrogênio, gesso e calcário utilizadas não induziram Deficiências detectadas visualmente no gladíolo. O menor tempo de florescimento e a maior matéria fresca das plantas de gladíolo foram obtidos sem o uso de calcário e/ou de gesso. As doses de calcário entre 6000 a 8000 kg.ha-1, contribuíram para obtenção de níveis ideais de pH em água para o gladíolo. A dose de nitrogênio de 300 kg.ha-1, promoveu a redução do pH, Ca e Mg e de argila dispersa em água e aumentou o grau de floculação e os teores de Al.
4

EFEITO DO NITROGÊNIO, CALCÁRIO E GESSO AGRÍCOLA EM ALGUNS ATRIBUTOS DE UM LATOSSOLO E NO DESENVOLVIMENTO DE GLADÍOLO / NITROGEN, LIMESTONE AND PHOSPHOGYPSUM EFFECTS IN SOME LATOSOL CHARACTERISTICS AND GLADIOLUS DEVELOPMENT

Gancedo, Marcelo 29 March 2007 (has links)
Made available in DSpace on 2016-02-26T12:59:15Z (GMT). No. of bitstreams: 1 MarceloGancedo.pdf: 341813 bytes, checksum: 7979c040bfdc034605ce046a6a950ead (MD5) Previous issue date: 2007-03-29 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / This work was developed in Gardening at UFMS (Universidade Federal de Mato Grosso do Sul) NCA (Núcleo Experimental de Ciências Agrárias), from September 2004 to February 2006 having the aim of valuating nitrogen, limestone and phosphogypsum over gladiolus development and over some chemical and physical characteristics of a dystroferric red latosol. Plants were valuated by leaf analysis, maximum high, spike and floral stem length, new corm diameter, dry and live mater form shoot area, and produced cormel number. Soil physical characteristics valuated the meaning clay, the meaning clay disperse in water, flocculation degree, aggregation and aggregation stableness. Soil chemical characteristics considered water and CaCl2 pH, macro and micronutrients meaning, exchangeable acidity, effective kation exchange capacity and base saturation. The experiment analysis was done in randomized blocks sub-subdivided in parcels, considering as parcel the nitrogen proportions (150, 300 kgha-1), as sub parcel the limestone proportion (0, 2000, 4000, 8000 kgha-1) and as sub-sub parcel phosphogypsum proportion (0, 500, 1000, 2000 kgha-1), in four repetitions. Nitrogen, limestone and Phosphogypsum proportions used caused no visual deficiencies detected in gladiolus. The smaller flowering time and the bigger live matter plants were gained without using limestone and / or phosphogypsum. Limestone between 6000 and 8000 kg.ha-1, contributed into ideal pH levels / Este trabalho foi desenvolvido na área de Jardinocultura do Núcleo Experimental de Ciências Agrárias da UFMS, durante o período de setembro de 2004 a fevereiro de 2006 tendo por objetivo a avaliação dos efeitos do nitrogênio, calcário e gesso agrícola sobre o desenvolvimento de Gladiolus grandiflorus e sobre alguns atributos físicos e químicos de um Latossolo Vermelho distroférrico. As plantas foram avaliadas por meio de análise foliar e quanto à altura máxima, comprimento da espiga e da haste floral, diâmetro do novo cormo, matéria fresca e seca da parte aérea e número de cormilhos produzidos. Como atributos físicos do solo foram avaliados o teor de argila, teor de argila dispersa em água, grau de floculação, agregação e estabilidade dos agregados. Os atributos químicos considerados foram o pH em água e em CaCl2, teores de macro e micronutrientes, acidez trocáveis, capacidade de troca de cátions efetiva e saturação de bases. O experimento foi analisado como inteiramente casualizado, em parcelas sub-subdivididas, sendo consideradas como parcelas as doses de nitrogênio (150 e 300 kg.ha-1), como subparcelas as doses de calcário (0, 2000, 4000 e 8000 kg.ha-1) e como sub-subparcelas as doses de gesso (0, 500, 1000 e 2000 kg.ha-1), com quatro repetições. As doses de nitrogênio, gesso e calcário utilizadas não induziram Deficiências detectadas visualmente no gladíolo. O menor tempo de florescimento e a maior matéria fresca das plantas de gladíolo foram obtidos sem o uso de calcário e/ou de gesso. As doses de calcário entre 6000 a 8000 kg.ha-1, contribuíram para obtenção de níveis ideais de pH em água para o gladíolo. A dose de nitrogênio de 300 kg.ha-1, promoveu a redução do pH, Ca e Mg e de argila dispersa em água e aumentou o grau de floculação e os teores de Al.
5

Development Of In Vitro Micropropagation Techniques For Saffron (crocus Sativus L.)

Yildirim, Evrim 01 August 2007 (has links) (PDF)
In vitro micropropagation of saffron (Crocus sativus L.) by using direct and indirect organogenesis was the aim of this study. Also, the effect of plant growth regulators on growth parameters, such as corm production, sprouting time and germination ratio were investigated in ex vitro conditions. For in vitro regeneration of saffron, the effects of 2,4-D (2,4-dichlorophenoxyacetic acid) and BAP (6-benzylaminopurine) were tested initially. It was observed that 0,25 mg/L 2,4-D and 1 mg/L BAP combination was superior for indirect organogenesis while 1 mg/L 2,4-D and 1 mg/L BAP combination was favorable for direct organogenesis. During the improvement of direct organogenesis experiments, BAP (1 mg/L) without 2,4-D stimulated further shoot development. For adventitious corm and root induction, NAA (naphthaleneacetic acid) and BAP combinations were tested. Although a few corm formations were achieved, root development was not observed with these treatments. Further experiments with the culture medium supplemented with 1 mg/L IBA (indole-3-butyric acid) and 5% sucrose was effective on obtaining contractile root formation and increasing corm number. As a result, the overall efficiency was calculated as 59.26% for contractile root formation, 35.19% for corm formation and 100% for shoot development. In ex vitro studies, 50 mg/L IAA (indole-3-acetic acid) , 50 mg/L kinetin and 200 mg/L GA3 (gibberellic acid) were used. These applications were not as efficient as expected on assessed growth parameters.
6

An investigation of the biology and chemistry of the Chinese medicinal plant, Amorphophallus konjac

Yee, Melinda Chua Fui January 2011 (has links)
Konjac glucomannan (KGM), the main biologically active constituent of konjac flour extracted from corms of Amorphophallus konjac (konjac), can be used to prepare functional foods and may also have potential as a pharmaceutical product to combat obesity. The current study employed three experimental approaches to study the biology and chemistry of konjac, namely (1) glasshouse experiments to study the morphogenesis, growth and productivity of konjac plants, (2) a histological and immunocytochemical investigation of the localisation and developmental regulation of the deposition and metabolism of KGM in developing corm tissues, and (3) a comparative study of methodologies for the extraction and analysis of KGM. The current data demonstrated a morphological and functional separation between the ventral and dorsal regions of corms. The ventral region appeared to function as a source during the initial period of shoot development, while the dorsal region appeared to operate as a sink after the development of mature canopy. Once the corm reached maturity, both an inflorescence and a leaf were produced within a single season. It has also been demonstrated that the age of the ‘mother’ corm is an important factor affecting the quality of offsets produced. An anti-mannan antiserum detected a temporally regulated pattern of mannan epitope production within glucomannan idioblasts in developing corm tissues, with increased expression as the corm approached maturity/dormancy. The current observations also suggest that the mobilization of KGM initiates at the periphery of the corm and proceeds inwards towards the centre of the corm. Compositional analysis showed that the purified konjac flour (PKF) produced using a modified extraction procedure contained 92% glucomannan, with a weight average molecular weight (Mw), polydispersity index (PDI) and degree of acetylation (DA) of 9.5 ± 0.6 x 105 gmol-1, 1.2 and 2.8 wt. %. These data, plus Fourier-transform infrared spectral (FTIR) and zero shear viscosity analyses of the extract (PKF) were all consistent with the literature. Comparison of three existing methodologies for the quantitative analysis of the KGM content, namely 3,5-dinitrosalicylic acid (3,5-DNS), phenol-sulphuric acid and enzymatic colorimetric assays; indicated that the 3,5-DNS colorimetric assay was the most reproducible and accurate method, with a linear correlation coefficient of 0.997 and recoveries between 97% and 103% across three spiking levels of starch. In summary, this study has provided a better understanding of aspects of the biology and cultivation of A. konjac and has also produced methodologies which can be used as the basis for an improved good laboratory practice (GLP) for the commercial extraction and analysis of this multifunctional natural polymer.

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