Diss. (sammanfattning) Alnarp : Sveriges lantbruksuniv., 2001. / Härtill 6 uppsatser.

No description available.

No description available.

Memoria para optar al Título Profesional de Químico y al Grado de Magíster en Química, área de especialización en coloides / El metabolismo celular es un proceso natural en los organismos vivos que conduce inevitablemente a la producción de especies reactivas del oxígeno, conocidas como ROS, las cuales, son agentes oxidantes altamente reactivos capaces de atacar células, causando en ellas la pérdida de su estructura y funciones. El exceso de ROS en el organismo, un estado que se conoce como “estrés oxidativo”, es mantenido bajo control por mecanismos celulares y especies antioxidantes, evitando que se desencadenen enfermedades relacionadas con la oxidación celular. Entre las ROS se encuentra el oxígeno molecular singulete, O2(a¹Δg), especie que es capaz de reaccionar con gran variedad de moléculas biológicas, tales como el ADN, proteínas y lípidos, desempeñando roles perjudiciales y/o beneficiosos en el organismo. El O2(a¹Δg) es uno de los dos posibles estados excitados del oxígeno, pero es el único que tiene un tiempo de vida los suficientemente largo para ser relevante en las reacciones químicas en solución. Se puede generar por vía química, física o fotoquímica, siendo esta última la más utilizada por ser la más simple y controlable. La cinética de sus reacciones con sustratos, o desactivantes (Q), puede ser descrita en términos de la constante de velocidad de desactivación total, que incluye las vías de reacción química y física. El método ideal para evaluar, es la detección directa de la emisión fosforescente del O2(a¹Δg) en el infrarrojo cercano, utilizando la fotosensibilización como método de generación de O2(a¹Δg). Sin embargo, esta técnica tiene serias limitaciones debido a la sensibilidad de los detectores y la complejidad del proceso de decaimiento del O2(a¹Δg) en sistemas de interés biológico, cuya microheterogeneidad, hace que ocurran gradientes en la concentración local del O2(a¹Δg) afectando su reactividad, situación que puede ser parcialmente imitada en sistemas bien definidos, tales como soluciones de micelas y liposomas. El modelo más apto para entender las reacciones del O2(a¹Δg) en sistemas biológicos lo constituyen las vesículas unilamelares, las cuales, se componen de una única bicapa bien definida que permite distinguir en ellas dos pseudofases, una acuosa y otra lipídica. El modelamiento cinético en estos sistemas es una tarea compleja, pero cercana a lo que sucede a nivel celular. Como alternativa a la detección directa del O2(a¹Δg)en sistemas biológicos, en nuestro laboratorio se han sintetizado los derivados de furano; DFTA, HFDA y MFMA, que además de reaccionar eficientemente con O2(a¹Δg)a través de la vía química, pueden anclarse en la membrana desde la interfase, permitiendo estudiar la dinámica del oxígeno singulete y estimar su concentración estacionaria a distintas profundidades en la bicapa. Esta información, sumada a estudios teóricos relacionados con el transporte de moléculas pequeñas a través de la membrana lipídica, permiten obtener una aproximación cuantitativa de la distribución del O2(a¹Δg) en ella. En este trabajo se estudia, en soluciones de vesículas unilamelares de DODAC y de DPPC, la interacción del O2(a¹Δg) con los sustratos licopeno, ácido rosmarínico y ácido carnósico, en forma independiente. Los tres sustratos poseen un origen natural y conocida capacidad antioxidante. En el experimento, el O2(a¹Δg)es generado por fotosensibilización, mientras que las soluciones de vesículas, con los derivados de furano y los antioxidantes incorporados en la bicapa, son generadas por el método de inyección… / Cellular metabolism is a natural process in living organisms that inevitably leads to the production of reactive oxygen species, known as ROS, which are highly reactive oxidizing agents capable of attacking cells, causing the loss of their structure and functions. The excess of ROS in the body, a condition known as “oxidative stress” is kept under control by cellular mechanisms and antioxidant species, avoiding the triggering of diseases related to cell oxidation. Among the ROS, singlet molecular oxygen O2(a¹Δg) is a specie capable of reacting with a variety of biological molecules, such as DNA, proteins and lipids, playing harmful and/or beneficial roles in the body. O2(a¹Δg) is one of the two possible excited states of the oxygen, but is the only one with a lifetime long enough for relevant chemical reactions in solution. It can be generated in a chemical, physical and photochemical way, the last being the most used method, being the simplest and most controllable. The kinetics of its reactions with other substrates, or quenchers, may be described in terms of the total deactivation rate constant including pathways for chemical and physical reactions. The ideal method to evaluate is the detection of the phosphorescence in the near-infrared, usually using photosensitization as a generating method for O2(a¹Δg). However, this technique has serious limitations due to the sensitivity of detectors and the complexity of the decay process in systems of biological interest, where the microheterogeneity, characteristic of biological systems, makes gradients occur in the local concentration and reactivity of O2(a¹Δg), a situation that can be partly replicated in well-defined systems such as micelles and liposomes solutions. The most suitable model to understand the reactions of O2(a¹Δg) in biological systems are unilamellar vesicles, which are composed of a single bilayer well defined to distinguish two pseudofases therein, aqueous and lipidic. The kinetic modeling of these systems is complex, but close to what happens at the cellular level. As an alternative to direct detection of O2(a¹Δg) in biological systems, several derivate of furan (DFTA, HFDA and MFMA) have been synthesized in our laboratory, which in addition to react efficiently with O2(a¹Δg) through chemicals pathways, they can be anchored to the membrane from the interface, allowing to study the dynamics of singlet oxygen and estimate their stationary concentration at different depths inside the bilayer. This information, together with theoretical studies related to the transport of small molecules through the lipid membrane allows obtaining a quantitative approach about the distribution of O2(a¹Δg) in the bilayer. In this work, a study concerning the interaction of O2(a¹Δg) with the substrates lycopene, rosmarinic acid and carnosic acid, in solutions of unilamellar vesicles of DODAC and DPPC, is presented. The three substrates possess a natural origin and a known antioxidant capability. In the experiment O2(a¹Δg) is generated by photosensitization, while solutions of vesicles, with the furan derivatives and antioxidants incorporated in the bilayer, are generated by the injection method. HFDA is the furan derivative that places the reactive group deeper into the bilayer, and thus, the one that probes more information regarding to the O2(a¹Δg) inside, is obtained for the three antioxidants through a kinetic model of two pseudofases, previously developed in our laboratory, where molecules of antioxidants and HFDA competing for reaction with O2(a¹Δg). The values of ,are also obtained by time-resolved methods, in order to make a comparison between them and obtained through the salts of furan by the method of the competitive reactions. The values of obtained for lycopene are close to those obtained by other authors in similar conditions. On the other hand, for rosmarinic and carnosic acids do not exist previous studies specifically related to O2(a¹Δg), however, the high value of the obtained for these substrates indicates that they play a significant protective effect against damage caused by O2(a¹Δg) in lipidic membranes, finding values in one order of magnitude higher than to those determined in methanol. / Conicyt, Fondecyt

Memori a para optar al Titulo Profesional de Ingeniero Agrónomo Mención: Fitotecnia / La presente investigación se realizó con el objeto de evaluar 22 cultivares de tomate industrial para pasta, desde el punto de vista de la caracterización de su etapa productiva y de la calidad de sus frutos como materia prima. Esto debido a que hoy en día son varios los cultivares de tomate industrial que han sido introducidos en el país, y anualmente aparecen otros con nuevas características para satisfacer los requerimientos de los productores y de los consumidores. Así la elección del cultivar debe ser lo más cuidadoso posible ya que la materia prima para industrialización debe tener características especiales.

Recent reports, especially those of Russian scientists, have emphasized that application of stimulatory concentrations of naphthenates (Naps) induced greater and better growth and productivity of a number of species of plants. This stimulatory action of Naps has been found to result from seed soaking and spraying seeds or developing plants once or repeatedly. However, no systematic attempt has so far been made to investigate physiological and biochemical changes induced in a relative short period following immediately these treatments. A correlation of such changes with final improvements in growth and yield may provide a better understanding of the mechanism of action of Naps It was therefore essential and significant to investigate these aspects. Seeds of tomato (Lycopersicum esculentum var. Bonny Best) were germinated in wooden flats containing sterilized soil and were transplanted when 10 days old to plastic pots of 6 inche diameter containing sterilized soil. The plants were grown in a growth room. In separate experiments, potassium naphthenate (KNap) aqueous solutions, 2,500 ppm and 5,000 ppm, were sprayed onto tomato leaves when plants were 2, 3, and 4 weeks old. Measurements of vegetative growth, based on fresh and dry weights of plant tops, indicated that maximum stimulation was induced by the 5,000 ppm KNap solution applied to plants when 3 weeks old. It was then decided to investigate the biochemical and physiological responses of the tomato plants to 5,000 ppm KNap when treated at the age of 3 weeks. Determinations of pigment content, intensities of photosynthesis and respiration, activity of enzymes involved in nitrogen metabolism, such as nitrate reductase (NRase) and glutamic-pyruvic transaminase (transaminase), and of enzymes involved in carbohydrate metabolism, such as succinic dehydrogenase, phosphorylase, and phosphoglyceryl kinase were made three times at 2-week intervals, beginning 2 weeks after the spraying. Number and fresh weight of tomato fruits, quality of tomato fruits in terms of sugars, titratable acidity and ascorbic acid were also investigated at scheduled intervals. Results indicated the following: (1) In the treated plants, the content of the pigments chlorophyll a and b, and especially carotenoid, in the leaf blades was higher than in control plants, (2) Measurements made with intact plants using an infrared CO₂ analyzer revealed increases in intensities of photosynthesis and respiration of the aerial portions 4 weeks after treatment but the opposite was true 2 weeks after treatment, (3) Under the influence of KNap, of the 5 enzymes examined only phosphorylase activity was found to be stimulated at all three observation times. Transaminase activity was greater 6 weeks after treatment. Activities of succinic dehydrogenase, NRase, and phosphoglyceryl kinase were all reduced by treatments, (4) In a subsequent experiment, leaf blades of plants treated when 2 weeks old were analyzed for succinic dehydrogenase activity 4, 8, 12, 16, 20, and 24 days after spraying. The effect on succinic dehydrogenase activity fluctuated with the age of the plant. Parallel changes in the protein content of the enzyme extract could not be detected, (5) Tomato fruit yield, based on number and fresh weight, was decreased by 2,500 ppm KNap treatment but increased by 5,000 ppm KNap. In addition, 5,000 ppm KNap-treated plants were more resistant to blossom-end rot and showed better and quicker recovery when the deficiency disease was treated with CaCl₂. Earlier maturity was found in 5,000 ppm KNap-treated plants, (6) The mature tomato fruits from 5,000 ppm KNap-treated plants contained larger amounts of sugars (reducing sugar and sucrose) than the controls, and the sugars in mature tomato fruits were lost at a lower rate during the storage period. The treatment resulted in decreased titratable acid and ascorbic acid content. It afforded no protection against loss of titratable acid and ascorbic acid during storage. / Science, Faculty of / Botany, Department of / Graduate

No description available.

Actinomicetos endofíticos de tomateiro (Lycopersicon esculentum) têm recebido atenção especial como potencial produtores de novos compostos bioativos e agentes de bicontrole contra fitopatógenos. Portanto, este trabalho teve como objetivo isolar e caracterizar actinomicetos endofíticos de tomateiro que apresentem atividade antimicrobiana contra fungos e bactérias de importância clínica e/ou agronômica, selecionar o microrganismo com melhor potencial antimicrobiano, caracterizar este isolado, otimizar as condições de produção do(s) composto(s) e realizar testes in vivo com o potencial agente de biocontrole. Actinomicetos foram isolados das raízes desinfestadas de tomateiro e foram submetidos ao teste de antibiose pelo método de dupla camada contra 39 microrganismos de importância clínica e 16 fitopatogênicos. Todos os actinomicetos foram caracterizados em nível de gênero através de características morfológicas e moleculares. A otimização da produção foi realizada empregando AC, TSB, ISP2, Sahin, Czapeck-Dox, Bennett’s e LNMS como meios de cultura e nas temperaturas de 30, 35 e 40°C. A atividade antimicrobiana foi avaliada pela técnica de difusão em ágar. O teste in vivo foi realizado em casa de vegetação e foi avaliada a capacidade do actinomiceto proteger o tomateiro contra a murcha bacteriana ocasionada por Ralstonia solanacearum. Foram isolados 70 actinomicetos endofíticos, destes 55 foram do gênero Streptomyces sp., nove Microbispora sp., três Micromonospora sp. e três Nocardia sp. Dos 70 isolados, 88,6% apresentaram atividade antimicrobiana contra pelo menos um fitopatógeno e 87,1% inibiram os microrganismos clinicamente importantes. No processo de otimização da produção os isolados selecionados cresceram em todas as condições analisadas, entretanto somente apresentaram atividade em determinadas condições de cultivo. O isolado selecionado para o teste in vivo, R18(6), inibiu o desenvolvimento da murcha bacteriana em condições de casa de vegetação. Os actinomicetos isolados apresentaram potencial antimicrobiano. / Endophytic actinomycetes from tomato plant (Lycopersicon esculentum) receiving special attention because of its potential have been as a source for new bioactive compounds and as biocontroler agent against phytopathogens. Therefore, the aim of this study was to isolate and characterize endophytic actinomycetes from tomato with activity against bacteria and fungi of clinica and agriculture importance; to select the isolate with the best antimicrobial activity, to characterize this isolate, to optimize the growth and production, to carry out a test in vivo with selected biocontrol agent. Actinomycetes were isolated from tomato roots and were submitted of antibiose test using the double-layer agar method against 39 clinical important microorganisms and 16 phytopathogens. All actinomycetes were characterized in level of genus using morphogical characteristics and molecular analysis. The optimization of growth conditions and production were tested in SC, TSB, ISP2, Sahin, Czapeck-Dox, LNMS media culture and 30, 35 and 40°C temperature conditions. The antimicrobial activity was evaluated using the agarwell diffusion method. The test in vivo was carried out in greenhouse and the capacity of actinomycete to protect of tomato against wilt bacteria caused by Ralstonia solanacearum was evaluated. Seventy endophytic actinomycetes were isolated from the tomato roots. Out of these 55 were identified as Streptomyces sp, 9 as Microbispora sp., 3 as Micromonospora sp. and 3 as Nocardia sp.. Out of the 70 isolates 88.6% of the isolates inhibied at least on the tested phytopathogens and 87.1% inhibited the microorganisms with clinical importance. In the production optimization the select isolates grew in all conditions tested, however the production of the compounds was observed only in specific conditions of growth. The isolate R18(6), was select for the in vivo test, and in the greenhouse experiment the isolate inhibited the development of wilt bacteria in tomato plants under greenhouse conditions. The actinomycetes isolated in the work showed an excellent antimicrobial potential.

Actinomicetos endofíticos de tomateiro (Lycopersicon esculentum) têm recebido atenção especial como potencial produtores de novos compostos bioativos e agentes de bicontrole contra fitopatógenos. Portanto, este trabalho teve como objetivo isolar e caracterizar actinomicetos endofíticos de tomateiro que apresentem atividade antimicrobiana contra fungos e bactérias de importância clínica e/ou agronômica, selecionar o microrganismo com melhor potencial antimicrobiano, caracterizar este isolado, otimizar as condições de produção do(s) composto(s) e realizar testes in vivo com o potencial agente de biocontrole. Actinomicetos foram isolados das raízes desinfestadas de tomateiro e foram submetidos ao teste de antibiose pelo método de dupla camada contra 39 microrganismos de importância clínica e 16 fitopatogênicos. Todos os actinomicetos foram caracterizados em nível de gênero através de características morfológicas e moleculares. A otimização da produção foi realizada empregando AC, TSB, ISP2, Sahin, Czapeck-Dox, Bennett’s e LNMS como meios de cultura e nas temperaturas de 30, 35 e 40°C. A atividade antimicrobiana foi avaliada pela técnica de difusão em ágar. O teste in vivo foi realizado em casa de vegetação e foi avaliada a capacidade do actinomiceto proteger o tomateiro contra a murcha bacteriana ocasionada por Ralstonia solanacearum. Foram isolados 70 actinomicetos endofíticos, destes 55 foram do gênero Streptomyces sp., nove Microbispora sp., três Micromonospora sp. e três Nocardia sp. Dos 70 isolados, 88,6% apresentaram atividade antimicrobiana contra pelo menos um fitopatógeno e 87,1% inibiram os microrganismos clinicamente importantes. No processo de otimização da produção os isolados selecionados cresceram em todas as condições analisadas, entretanto somente apresentaram atividade em determinadas condições de cultivo. O isolado selecionado para o teste in vivo, R18(6), inibiu o desenvolvimento da murcha bacteriana em condições de casa de vegetação. Os actinomicetos isolados apresentaram potencial antimicrobiano. / Endophytic actinomycetes from tomato plant (Lycopersicon esculentum) receiving special attention because of its potential have been as a source for new bioactive compounds and as biocontroler agent against phytopathogens. Therefore, the aim of this study was to isolate and characterize endophytic actinomycetes from tomato with activity against bacteria and fungi of clinica and agriculture importance; to select the isolate with the best antimicrobial activity, to characterize this isolate, to optimize the growth and production, to carry out a test in vivo with selected biocontrol agent. Actinomycetes were isolated from tomato roots and were submitted of antibiose test using the double-layer agar method against 39 clinical important microorganisms and 16 phytopathogens. All actinomycetes were characterized in level of genus using morphogical characteristics and molecular analysis. The optimization of growth conditions and production were tested in SC, TSB, ISP2, Sahin, Czapeck-Dox, LNMS media culture and 30, 35 and 40°C temperature conditions. The antimicrobial activity was evaluated using the agarwell diffusion method. The test in vivo was carried out in greenhouse and the capacity of actinomycete to protect of tomato against wilt bacteria caused by Ralstonia solanacearum was evaluated. Seventy endophytic actinomycetes were isolated from the tomato roots. Out of these 55 were identified as Streptomyces sp, 9 as Microbispora sp., 3 as Micromonospora sp. and 3 as Nocardia sp.. Out of the 70 isolates 88.6% of the isolates inhibied at least on the tested phytopathogens and 87.1% inhibited the microorganisms with clinical importance. In the production optimization the select isolates grew in all conditions tested, however the production of the compounds was observed only in specific conditions of growth. The isolate R18(6), was select for the in vivo test, and in the greenhouse experiment the isolate inhibited the development of wilt bacteria in tomato plants under greenhouse conditions. The actinomycetes isolated in the work showed an excellent antimicrobial potential.

Submitted by Marco Antônio de Ramos Chagas (mchagas@ufv.br) on 2017-05-08T18:51:24Z No. of bitstreams: 1 texto completo.pdf: 3016157 bytes, checksum: 362c5f16a4717763663adf239c105fa9 (MD5) / Made available in DSpace on 2017-05-08T18:51:24Z (GMT). No. of bitstreams: 1 texto completo.pdf: 3016157 bytes, checksum: 362c5f16a4717763663adf239c105fa9 (MD5) Previous issue date: 2000-09-15 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / A família Geminiviridae compreende um grupo de vírus de plantas que são empacotados em vírions como DNA fita simples e ocorrem como DNA fita simples e fita dupla nas células infectadas. Seu genoma pode ser monopartido ou bipartido. O genoma dos geminivírus bipartidos é dividido em dois componentes genômicos, denominados DNA A e DNA B. Utilizando-se ensaios de PCR, foram detectados geminivírus em plantas sintomáticas de tomateiros (Lycopersicon esculentum), coletadas nos Estados de Minas Gerais e Rio de Janeiro, Brasil. Com oligonucleotídeos degenerados específicos para cada componente, fragmentos de tamanhos esperados, correspondentes aos componentes A e B de geminivírus, foram amplificados a partir do DNA total de tomateiros infectados. Esses resultados confirmaram a natureza bipartida destes geminivírus. Os fragmentos amplificados, contendo as regiões intergênicas mais as seqüências flanqueadoras 3' e 5', foram clonados e seqüenciados. A análise comparativa das seqüências revelou que os fragmentos destes geminivírus apresentam moderada conservação de seqüência com outros membros do gênero Begomovirus e preenchem os requerimentos para serem caracterizados como novos vírus distintos. Suas regiões intergênicas diferem significativamente na seqüência de nucleotídeos, e a seqüência deduzida de aminoácidos da região N- terminal de suas proteínas capsidiais não supera 85% de identidade com outras espécies do gênero Begomovirus. Coletivamente, esses resultados indicam que os dois geminivírus que infectam tomateiro, detectados em plantas coletadas nos Estados do Rio de Janeiro e Minas Gerais, são novas espécies da família Geminiviridae. O geminivírus do Estado do Rio de Janeiro, aqui designado TYhMV ("Tomato yellowish mosaic virus"), foi parcialmente caracterizado com a clonagem e o seqüenciamento completo do componente B. A taxonomia do novo vírus foi confirmada pela análise filogenética baseada na seqüência do componente B e na seqüência deduzida de aminoácidos das proteínas BV1 e BC1. Esses resultados confirmaram que o novo vírus pode ser classificado como uma espécie distinta de Begomovirus, sendo mais relacionado com os Begomovirus TGMV e BGMV, previamente identificados no Brasil. A tentativa de clonagem do componente A completo amplificado com oligonucleotídeos específicos resultou em quatro clones distintos, os quais compartilham a seqüência da região intergênica. Embora estes clones não tenham sido totalmente caracterizados, a comparação de suas regiões intergênicas com a correspondente região do componente B clonado revelou que eles compartilham 98,5% de identidade de seqüência. O alto grau de conservação da seqüência de suas regiões intergênicas indica que o componente B clonado e os clones do componente A pertencem ao genoma de TYhMV. / The Geminiviridae family comprises a group of plant viruses that are packaged as single-stranded DNA in virions and exist as single-stranded and double-stranded DNA in infected cells. Their genome can be either monopartite or bipartite. The genome of the bipartite geminiviruses is spliced between two genomic components, designated DNA A and DNA B. We have used a PCR- based diagnostic assay to detect geminiviruses in symptomatic tomato (Lycopersicon esculentum) plants, collected in the states of Minas Gerais and Rio de Janeiro, Brazil. With degenerate primers specific for each component, the correctly sized fragments corresponding to A and B components of geminiviruses were amplified from DNA extracts of tomato plants. These results confirmed the bipartite nature of these geminiviruses. The amplified fragments corresponding to the intergenic region plus 5' and 3' flanking sequences were cloned and sequenced. Sequence comparison analysis revealed that they share a moderate conservation of sequences with other members of the Begomovirus genus and fit well into the requirements for distinct, new viruses. Their intergenic regions differ significantly in nucleotide sequence and the deduced N-terminal regions of their coat protein share no more than 85% identity with other species of the Begomovirus genus. Taken together, these results indicate that the two tomato-infecting geminiviruses detected in plants collected in the states of Minas Gerais and Rio de Janeiro, Brazil, are distinct, new species of the family Geminiviridae. The tomato-infecting geminivirus from Rio de Janeiro, here designated TYhMV (tomato yellowish mosaic virus), was further characterized by full-length cloning and sequencing of its B component. The taxonomy of the new virus was further confirmed by phylogenetic analysis based on the sequence of the B component and the deduced aminoacid sequence of the BV1 and BC1 proteins. These results confirmed that the new virus may be classified as a distinct species of Begomovirus, more related to other previously characterized Begomovirus from Brazil, such as TGMV and BGMV. Attempts to clone the fully amplified A component with specific primers resulted in four distinct clones, which share the same sequence of the intergenic region. Although these clones have not been fully characterized, comparison of their intergenic region with the corresponding region of the cloned B component revealed that they share 98.5 % sequence identity. The high degree of sequence conservation of their intergenic regions indicates that the cloned B component and the clones of the A component belong to the genome of TYhMV. / Dissertação importada do Alexandria