• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 7
  • 7
  • 3
  • Tagged with
  • 17
  • 6
  • 5
  • 4
  • 4
  • 4
  • 4
  • 4
  • 4
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 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.
11

Estratégias de aumento de eficiência da análise de produtos naturais por espectroscopia de ressonância magnética nuclear / Strategies to improve efficiency Natural Products analys by Nuclear Magnetic Resonance Spectroscopy

Edilene Delphino Rodrigues 26 March 2010 (has links)
Dois dos principais aspectos da Química de Produtos Naturais são a identificação e a determinação estrutural dos compostos orgânicos presentes em materiais de origem vegetal ou animal. Para realizar esta tarefa são empregados diversos métodos de separação e espectroscópicos. Dentre os métodos espectroscópicos, destaca-se a espectroscopia de ressonância magnética nuclear pela riqueza dos dados fornecidos. Entretanto, o desenvolvimento da área exige métodos cada vez mais eficientes e sensíveis, para permitir o estudo de amostras em quantidades cada vez menores. Neste trabalho, empregamos três estratégias distintas para aumentar a eficiência da análise de amostras de produtos naturais por RMN. A primeira estratégia busca acelerar o processo de identificação dos componentes de frações de extratos vegetais através da separação virtual dos componentes da mistura, baseada nas diferenças de seus coeficientes de difusão. Esta estratégia permitiu identificar os quatro componentes majoritários da fração em acetato de etila do extrato etanólico das partes aéreas de Bidens sulphurea (Asteraceae) através de um estudo de RMN DOSY-2D. A segunda estratégia é dedicada ao problema da baixa sensibilidade da RMN 13C, o que torna difícil, e em alguns casos, proibitiva em termos do tempo necessário, a análise de amostras muito pequenas. Dada a dificuldade de se obter diretamente um espectro com uma relação sinal/ruído adequada, uma abordagem possível se baseia em estratégias de pós-processamento de um espectro de RMN em que predomina o ruído. A estratégia utilizada neste trabalho fornece um espectro reconstruído de secções que foram previamente processadas para a eliminação do ruído pela decomposição do valor singular (SVD). Os espectros assim processados nos auxiliaram na identificação e/ou elucidação estrutural de dois alcalóides obtidos de Duguetia furfuraceae (Annonaceae) e um poliacetileno e dois flavonóides de B. sulphurea (Asteraceae). A terceira estratégia utilizada neste trabalho se baseia na ampliação dos parâmetros rotineiramente obtidos numa análise por RMN, com a finalidade de fornecer novos subsídios para a determinação da estrutura de produtos naturais. Neste sentido, a determinação das constantes de acoplamento heteronuclear forneceu dados valiosos para a identificação de dois poliacetilenos obtidos de B. gardneri. / Two major aspects of Natural Products Chemistry are the identification and structure determination of organic compounds in materials of vegetable or animal. To accomplish this task are used various methods of separation and spectroscopic. Among spectroscopic methods, we highlight the spectroscopy of nuclear magnetic resonance by the wealth of data provided. However, the development of the area requires methods increasingly efficient and sensitive to allow the study of small or diluted samples. In this work, we employ three different strategies to increase the efficiency of analysis of samples of natural products by NMR. The first strategy seeks to accelerate the process of identifying the components of fractions of plant extracts through the virtual separation of the components of the mixture based on differences in their diffusion coefficients. With this strategy we have identified four major components of the in ethyl acetate fraction of ethanol extract of aerial parts of Bidens sulphurea (Asteraceae) by 2D DOSY NMR. The second strategy is devoted to the problem of low sensitivity of 13C NMR, which makes it difficult, and in some cases prohibitive in terms of time, the analysis of very small samples. Due to the difficulty of obtaining directly a spectrum with a signal-to-noise ratio adequate, a possible approach is based on strategies for post-processing of an NMR spectrum in which noise predominates. This strategy used here provides a spectrum of reconstructed sections were first processed to remove noise by singular value decomposition (SVD). Spectra processed of this way helped us in identifying and / or structural elucidation of two alkaloids derived from Duguetia furfuraceae (Annonaceae) and a polyacetylene and two flavonoids from Bidens gardneri (Asteraceae). The third strategy used in this work is based on expansion of the parameters routinely obtained in an analysis by NMR in order to provide new subsidies for the structure determination of natural products. In this sense, the determination of heteronuclear coupling constants provided valuable data for the identification of two polyacetylenes obtained from B. gardneri.
12

Mycorrhizal association, propagation and conservation of the myco-heterotrophic orchid Rhizanthella gardneri

Mursidawati, Sofi January 2004 (has links)
Many orchids require mycorrhizal symbioses with fungi for their development and survival. Rhizanthella gardneri the Western Australian underground orchid is associated with the companion plant Melaleuca uncinata and its ectomycorrhizal fungus symbiont. Much less is known about the habitat requirements of its sister species, R. slateri, which occurs in Eastern Australia. The absence of chlorophyll from Rhizanthella gardneri and R. slateri results in total dependency on associations with fungal symbionts. Many ecological and biological aspects of these fascinating orchids remained poorly known, including the identity of the fungal associates and the nature of their tripartite associations with Rhizanthella and Melaleuca. Extremely high specificity of these mycorrhizal relationships is likely to be the most important factor explaining the highly specific habitat requirements of underground orchids. The purpose of this study was to conduct further investigations of the role of the mycorrhizal associations of Australian underground orchids by identifying the fungi involved in these associations, optimising their growth in sterile culture and devising efficient means for synthesising their tripartite associations with R. gardneri and M. uncinata. In total, 16 isolates of fungi were successfully obtained from the two underground orchids and used in a series of experiments to understand both the nature of the fungi and their relationship with orchids. The identity of these fungi was established by using conventional morphological and molecular methods. Cultural and morphological studies revealed that all isolates from R. gardneri and R. slateri were binucleate rhizoctonias with affinities to members of the genus Ceratobasidium. However, the teleomorph state that was observed from the R. slateri symbiont during this study more closely resembled a Thanatephorus species. Further identification using ITS sequence comparisons confirmed that mycorrhizal fungi of Rhizanthella belonged to the Rhizoctonia alliance with relatives that include Thanatephorus, Ceratobasidium, or Rhizoctonia from other continents with over 90% similarity. Most of these related fungi are known as plant pathogens, but some were orchid mycorrhizal fungi. However, the isolates from the two underground orchids were most closely related to each other and formed a discrete group relative to other known members of the Rhizoctonia alliance. Sterile culture experiments determined culture media preferences for mycorrhizal fungi from Rhizanthella and other orchids. A fully defined sterile culture medium designed to more closely resemble Australian soil conditions was formulated. This new medium was compared to undefined media containing oats or yeast extract and recommendations for growth of these fungi are provided. The undefined media based on oats provided the best growth of most fungi, but the new Australian soil media was also effective at growing most orchid mycorrhizal fungi and this fully defined media was less prone to contamination and should provide more reproducible results. A comparison of three methods for inoculating M. uncinata with the underground orchid fungi resulted in the production and characterisation of ectomycorrhizal roots and hyphae formed by fungi isolated from R. gardneri and R. slateri. These underground orchid fungi could easily be distinguished from other mycorrhizal fungi (caused by airborne contamination) by the characteristic appearance of these roots and hyphae. A new system for growing and observing tripartite mycorrhizal associations was devised using pots with side viewing windows and the use of transparent seed packets to contain Rhizanthella seeds. This method allowed all the stages of seed germination to be observed in the glasshouse, culminating in the production of underground orchid rhizomes. Seed germination was only successful when seed was placed directly over active M. uncinata ectomycorrhizas confirmed to belong to the correct fungus by microscopic observations through the side of window pots. The importance of these new scientific discoveries concerning the biology and ecology of the underground orchids and their associated fungi for the recovery of these critically endangered orchids are discussed.
13

Development of tomato (S. lycopersicum) lines with resistance to Xanthomonas spp. and use of genetic resources to characterize infection and diversity in pathogen populations

Bernal, Eduardo January 2020 (has links)
No description available.
14

Celková tvrdost vody a pH při vývoji jiker u vybraných druhů akvarijních ryb / The total water hardness and pH during the egg development in selected aquarium fish species

FRANTL, Zdeněk January 2010 (has links)
Objectives of thesis: 1.To evaluate the effect of pH and total hardness of water on the development of eggs in aquarium fish Corydoras paleatus, Corydoras paleatus albin, Tanichthys albonubes, Tanichthys albonubes gold, Aphyosemion gardneri, Aphyosemion gardneri gold. 2.Recommendation of optimal values of total hardness of water and pH for successful development of eggs for each monitored aquarium fish. Based on published data in available literature sources and on own experiments, it was evaluated how total water hardness (CM) and pH influences development of aquarium fish eggs of Aphyosemion gardneri, Aphyosemion gardneri gold, Tanichthys albonubes, Tanichthys albonubes gold, Corydoras paleatus, Corydoras paleatus albin.
15

Characterization and Management of Bacterial Leaf Spot of Processing Tomato in Ohio

Ma, Xing January 2015 (has links)
No description available.
16

Development of Processing Tomato Lines Resistant to <i>Xanthomonas gardneri</i>: from Screening to Breeding

Liabeuf, Debora January 2016 (has links)
No description available.
17

Ação de produtos químico in vitro, em mudas e em campo sobre a mancha bacteriana (Xanthomonas perforans e X. gardneri) em tomate para processamento industrial / Chemical control of the bacterial spot in tomato for industrial processing: sensibility in isolated vitro and efficiency of products in seedlings and in field

NASCIMENTO, Abadia dos Reis 17 February 2009 (has links)
Made available in DSpace on 2014-07-29T14:52:10Z (GMT). No. of bitstreams: 1 abadia tese.pdf: 6055071 bytes, checksum: 41810223bb4492258f77c027a3385652 (MD5) Previous issue date: 2009-02-17 / The search of alternative products for tomato bacterial spot has been promoting by the lack of effectiveness registered by the traditional products available. The objective of this work was to evaluate a range of chemical products by in vitro tests, in experiments seedlings and field experiments. The products studied were: acibenzolar-S-methyl; benzalkonium chloride; phosphite; copper hydroxide, copper oxicloreto; metiram + pyraclostrobin and famoxadone + mancozebe. The in vitro tests were carried out at Embrapa Hortaliça, Brasília-DF, in July of 2007. The bactericide action was evaluated on Xanthomonas perforans and X. gardneri. The trial was in a complete randomized block design with four replications and plot was constituted by a Petri plate impregnated with solidified bacterial suspension. The halo of inhibition formed was evaluated. The experiments with seedlings were carried out with the hybrid Heinz 9553 at the commercial nursery VIVATI in Rio Verde, Goiás, in August to September and November to December of 2008. There were three trials in a complete randomized block design with three replications. The products were sprayed by using CO2 portable sprayer. The inoculation occurred 29 days after sowing, with an isolated of X. gardneri. Disease severity was evaluated on 15 leaflets per plot at 14 and 16 days after inoculation of the first and second experiment, respectively. Data was expressed as percentage of leaf affected by program Quant. It was also suggested a possible interaction between the regulator of growth paclobutrazol and the behavior of certain products in the reduction of the severity of the disease. Two field trials were carried out at the experimental farm of Unilever Bestfoods, in Goiânia-GO, from February to June of 2007 and April to August of 2008. The first was with the hybrid Heinz 9992 in a complete randomized block design, with 15 treatments and three replications, and inoculated with X. perforans. The second was in a split plot completely randobized block design with three replications. Variety (Hypeel 108 and U2006) was ascertained for factor A and the 10 treatments for factor B. Xanthomonas perforans and X. gardneri were inoculated in different moments. In both trials foliage severity, number of fruits with symptoms and yield were evaluated. In the second trial fruits with sun scald was also taken. In the in vitro test, the products to which X. perforans and X. gardneri were sensitive in the recommended dose were the benzalkonium chloride and famoxadone + mancozeb. Methiram + pyraclostrobin had action in the dosage recommended only for X. gardneri. Xanthomonas perforans was sensitive to this product only starting from ten times more. The products of copper base did not have action in the bacteria at the recommended dose, being sensitive only at a hundred time more. For the trials of seedlings it was noticed that metiram + pyraclostrobin, copper oxicloreto, famoxadone + mancozebe, phosphite and copper hydroxide reduced the severity under certain conditions. In the field trials, in generally, acibenzolar-S-methyl and famoxadone + mancozeb lead to the better results. / A pouca disponibilidade de produtos eficazes tem propiciado a busca por alternativas de controle da mancha bacteriana do tomateiro. Sendo assim, este trabalho teve como objetivo avaliar uma gama de produtos químicos em testes in vitro, experimentos com mudas e em experimentos de campo. Foram estudados: acibenzolar-S-metil; cloretos de benzalcônio; fosfitos; hidróxido de cobre, oxicloreto de cobre; metiram + piraclostrobina e famoxadona + mancozebe. Os testes in vitro foram conduzidos na Embrapa Hortaliças, Brasília-DF, em julho de 2007. A ação bactericida dos produtos foi avaliada sobre Xanthomonas perforans e X. gardneri. O ensaio foi em blocos casualizados com quatro repetições e a parcela foi constituída por uma placa de Petri impregnada com suspensão bacteriana solidificada. Avaliou-se o halo de inibição formado. Os experimentos de mudas foram conduzidos com o híbrido Heinz 9553 no viveiro comercial VIVATI em Rio Verde GO, de agosto a setembro e de novembro a dezembro de 2008. Foram três ensaios inteiramente casualizados com três repetições. Os tratamentos (produtos) foram pulverizados na parte aérea utilizando pulverizador costal de barra. A inoculação foi aos 29 dias após a semeadura, com um isolado de X. gardneri. Avaliou-se a severidade da doença em 15 folíolos por parcela aos 14 e 16 dias após a inoculação do primeiro e segundo experimento, respectivamente. Esta foi expressa em porcentagem de área foliar atacada processada pelo programa Quant. É sugerido uma possível interação entre o regulador de crescimento paclobutrazol e o comportamento de certos produtos na redução da severidade da doença. Dois ensaios de campo foram conduzidos na área experimental da Unilever Bestfoods, em Goiânia-GO, de fevereiro a junho de 2007 e de abril a agosto de 2008. O primeiro foi com o híbrido Heinz 9992 em delineamento experimental blocos casualizados, com 15 tratamentos e três repetições. Inoculou-se X. perforans. Já o segundo ensaio foi fatorial em parcelas subdivididas em blocos ao acaso e três repetições. O fator A foi hídrido (Hypeel 108 e U2006) e o fator B (tratamentos). Inoculou-se X. perforans e X. gardneri em momentos distintos. Em ambos ensaios foram avaliados severidade foliar, número de frutos com sintomas e produtividade. No segundo ensaio tomou-se também número de frutos com escaldadura. No teste in vitro os produtos aos quais X. perforans e X. gardneri foram sensíveis na dose recomendada foram os cloretos de benzalcônio e a famoxadona + mancozebe. Metiram + piraclostrobina tiveram ação na dosagem recomendada somente para X. gardneri. Xanthomonas perforans foi sensível ao produto somente a partir de dez vezes maior a dosagem recomendada. Os produtos à base de cobre não tiveram ação nas bactérias na dosagem recomendada, sendo sensíveis apenas na dose cem vezes maior a dosagem recomendada. Em mudas metiram + piraclostrobina, oxicloreto de cobre, famoxadona + mancozebe, fosfito e hidróxido de cobre reduziram a severidade em mudas no ensaio realizado em agosto. Em campo, notou-se que, de maneira geral acibenzolar-S-metil e famozadona + mancozebe estão entre os melhores resultados.

Page generated in 0.0297 seconds