No description available.

No description available.

Understanding how hyphal organisms grow and develop is essential in order to manipulate mycelial colonies for purposes such as disease prevention and food production. One aspect of hyphal development that is not well understood is hyphal branching. Hyphal organisms branch as a way of creating new hyphal tips required for the search for nutrients, the acquisition of these nutrients and for hyphal fusion events that facilitate communication of signals within a mycelial colony. This investigation focused on the branching process occurring in the fungus N. crassa and in the oomycete A. bisexualis. An induction technique was developed to study branching in N. crassa involving local application of amino acids towards hyphae. This induced a branch to form along the hypha within the field of view. The use of this technique will enable the study of underlying events occurring internally prior to the visible branching stages. The role of Ca²⁺ hyphal branching was investigated in N. crassa suggesting Ca²⁺ is involved in apical dominance of the hyphal tip. This is based on a dose dependent response of increased branch frequency, decreased colony radius and decreased distance between the hyphal tip and the first branch, to the Ca²⁺ channel inhibitor verapamil. The stretch-activated Ca²⁺ channel inhibitors also had an effect on mycelial morphology. Gd³⁺ resulted in an increased branch frequency and a decreased colony radius and La³⁺ resulted in a decreased colony radius. The local application of verapamil towards N. crassa showed an increase in the number of multiple branches forming. Cytoplasmic Ca²⁺ was imaged in hyphae of A. bisexualis and N. crassa showing a tip-high Ca²⁺ gradient in A. bisexualis and Ca²⁺ sequestered into organelles in N. crassa. The role of F-actin in the process of hyphal branching was investigated using Lifeact N. crassa where F-actin could dynamically be seen at the site of both growing and non-growing hyphal branches. The involvement of F-actin at sites of septa development and associated with suspected vesicles was also observed.

Resumo: Objetivou-se o ajuste de metodologia e seleção de genótipos de guandu para resistência a Macrophomina phaseolina a partir de material obtido pela Embrapa Pecuária Sudeste, e verificar o desenvolvimento micelial e esporulação do fungo em meios de cultura. O trabalho foi conduzido em casa de vegetação na UNESP/Jaboticabal no período de agosto de 2004 a dezembro de 2005. Para o ajuste de metodologia e seleção de genótipos resistentes ao fungo as sementes foram submetidas a escarificação com lixa d'água e inoculação artificial através do método de exposição das mesmas ao patógeno por diferentes períodos, que variaram de O a 72 horas. Foram avaliadas porcentagem de plantas sobreviventes e massa fresca. Já para o crescimento micelial e esporulação do fungo foi utilizado o método de sobreposição de discos de diferentes hospedeiros no meio de cultura. A escarificação das sementes contribuiu para a penetração do fungo nas mesmas o período de 24h de exposição das sementes ao fungo são suficientes para detectar diferenças no grau de resistência dos genótipos. Os genótipos mais resistentes são g167-97, g124-95, g27-94, g40-95, g154-95, g127-97 e g9m-97, e os mais suscetíveis são g48-95, g123-95, g8-95, g168-99 e g1m-95. A sobreposição de discos foliares de guandu em meio BDA e folha de papel de filtro em meio sojinha proporcionam um incremento na esporulação de M. phaseolina. / Abstract: This work had the objective of determining the best schedule for artificial inoculation and select pigeon pea genotypes resistant to Macrophomina phaseolina in material obtained by Embrapa Pecuária Sudeste, and verify the mycelial growth and sporulation of the fungi in middle of culture. The work were carried in greenhouse at the UNESP/Jaboticabal, from August 2004 to December 2005. For the methodology and selection adjustment of resistant genotypes to the fungi the seeds were submitted scarified with water sandpaper and artificial inoculation the seeds were the contact method to fungi for different periods, which varied from O to 72 hours. They were evaluated percentage of surviving plants and fresh mass. For the mycelial growth and sporulation of the fungi was used the superposition of disks method of different hosts in the middle of culture. The scarified of the seeds contributed for penetration of the fungi at the seeds; the period of 24h of contact of the seeds to the fungi enough to detect differences in the resistance degree ofthe genotypes. The genotypes g167-97, g124-95, 927-94, g40-95, g154-95, g127-97 and g9m-97 were found to be the most resistant and most susceptible were g48-95, g123-95, g8-95, g168-99 and g1m-95. The treatment with superposition of the leaf disks of pigeon pea in BDA and disks of filter paper in middle of soybean extract were the treatments that provided better sporulation levei in the conditions of that experiment were half. / Orientador: Rita de Cássia Panizzi / Coorientador: Rodolfo Godoy / Banca: Antonio de Goes / Banca: Patrícia Menezes Santos / Mestre

An overview of the flavour and fragrance industry has indicated that there is a great demand for flavours to have the natural, halaal and kosher status. This has opened the door for the increase in production of flavours by microbial means. Particularly with regards to pyrazine production, bacterial species such as Bacillus are commonly used. Although previous literature indicated that fungi are not as prominent pyrazine producers compared to bacteria, this study has indicated that mycelial fungi can be considered for the production of natural pyrazine flavours. Out of the 280 fungi screened, 45% showed pyrazine flavour production as indicated in chapter 2. This chapter also showed that the content of growth media can have a substantial influence on flavour production. For example, fungi grown in Cz-medium produced more of the caramel and chocolate flavours, compared to fungi that were grown in TSB, which produced more of the nutty, meaty and potato flavours. The green flavour was, however, prominent in both media, of which mostly members of the Aspergillus and Penicillium groups produced this flavour. Selected Penicillium species, including Penicillium rubrum and P. purpurogenum produced a green pepper odour that is indicative of the presence of methoxypyrazine. Chemical analytical methods as described in chapter 3 confirmed that Penicillium purpurogenum produced 2-methoxy-3-isobutylpyrazine (MIBP) and Penicillium rubrum produced both 2-methoxy-3-isobutylpyrazine (MIBP) and 2-methoxy-3,5/6-isopropylpyrazine (MIPP). Methoxypyrazines are high impact aroma chemicals that have a typical green pepper odour and a high market value. Due to the favourable characteristics of the Penicillium species in industrial fermentation processes (such as mass spore production and rapid colonization of substrates) and their ability to produce high value compounds, these fungi were selected for further studies. In order to explore the potential use of these fungi in an industrial application, the methoxypyrazines produced were quantified. Prior to quantitation, a solvent extraction method, using dichloromethane, was developed. Amongst the different pH parameters analysed acidified conditions showed the best results, where 69% MIPP and 97% MIBP were recovered from the liquid-liquid extraction and 76% MIPP and 99% MIBP were recovered from the solid-liquid extraction. Pyrazines quantified from the liquid-liquid extractions indicated that Penicillium rubrum produced 0.38 μg MIPP.L-1 and 0.88 μg MIBP.L-1, and Penicillium purpurogenum produced 0.88 μg MIPP.L-1 and 2.15 μg MIBP.L-1 (Chapter 4). Yields obtained from this study were not seen as feasible for the production of methoxypyrazines by the fungi on an industrial scale and, therefore, solid state fermentation was investigated as an option to improve the yields. Due to the availability of soy press cake as a by-product, as well as the variety of the amino acids present, it was selected as a possible substrate for pyrazine production. The results from this study, however, indicated that the nature of the substrate, such as the lipid content, fungal content and particle size of the soy press cake does not support fungal growth and makes pyrazine analyses problematic. Alternate methods of improving methoxypyrazine yields thus need to be found. A limiting factor is the lack of understanding of the metabolic pathway involved in pyrazine production by Penicillium species. By having this knowledge the fermentation process can be adapted accordingly for the optimal production of methoxypyrazines by these microorganisms. Additionally, substrates that contain the necessary precursors that are cost effective would contribute significantly in the development of an economically viable fermentation process for the production of methoxypyrazines by Penicillium species. / Dissertation (MSc)--University of Pretoria, 2010. / Microbiology and Plant Pathology / unrestricted

No description available.

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No. of bitstreams: 1 Dissertação - Tamiris Rio Branco da Fonseca.pdf: 1102398 bytes, checksum: e70c786229e1b956a358698df9fb090b (MD5) Previous issue date: 2013-05-02 / CNPq - Conselho Nacional de Desenvolvimento Científico e Tecnológico / Mushrooms arouse interest for presenting high nutritional and medicinal value. The representatives of the genus Pleurotus are able to grow in different agricultural and agro-industrial waste, since they secrete numerous enzymes that hydrolyze the substrates prepared from waste providing nutrient The search for alternative substrates increased in recent years due to the availability of regional waste little or never used in the production of edible mushrooms. The use of waste in solid-state fermentation has emerged also in the production of enzymes. Proteases are a group of enzymes commercially exploited, however the use of Basidiomycetes as producers of proteases is still a relatively unexplored. The aim of this study was to evaluate the mycelial growth as well as to investigate the production and partially characterize extracellular proteases from Pleurotus ostreatoroseus DPUA 1720 in different agro-industrial waste, selecting a mixture for the production of the mushroom and check their microbiological quality and nutritional value. Cultures were prepared in potato dextrose added yeast extract 0.5% (w/v). The vertical mycelial growth and production of proteases from P. ostreatoroseus DPUA 1720 were performed in agro-industrial waste (acai seed, sawdust, cupuassu bark, rice bran, bark and pineapple crown) for 15 days under two growing conditions (presence and absence of light). The production of basidiomata was performed in the substrate which presented satisfactory mycelial growth and vigorous mycelium. From this bioprocess evaluated the formation and development of early basidiomata, total time of cultivation, biological efficiency, productivity, production rate, loss of organic matter, microbiological and nutritional value of the mushroom. P. ostreatoroseus DPUA 1720 grew in all industrial residues also tested serving as sources for the production of proteases. In bark cupuaçu added rice bran mycelium was strongly vigorous and the mycelial growth satisfactory, therefore selected for the production of P. ostreatoroseus DPUA 1720. Under the experimental conditions the proteolytic activity was determined in crude extracts from the substrates of vertical mycelial growth with maximum proteolytic activity (7.89 U/mL) in bark cupuassu added rice bran in the presence of light. This substrate was the most efficient for the production of proteases with activity atpH 6.0 and optimum temperature at 40 ˚C. The basidiomata showed no contaminants, low in fat, high in fiber and protein, macro and micro minerals, essential and non-essential amino acids, may therefore be inserted into the feed as a safe and nutritious food. / Os cogumelos despertam interesse por apresentar alto valor nutricional e medicinal. Os representantes do gênero Pleurotus são capazes de crescer em diferentes resíduos agrícolas e agroindustriais, pois secretam inúmeras enzimas que hidrolisam os substratos elaborados a partir dos resíduos disponibilizando nutrientes. A busca por substratos alternativos cresceu nos últimos anos em virtude da disponibilidade de resíduos regionais pouco ou nunca utilizados na produção de cogumelos comestíveis. O uso de resíduos na fermentação semi-sólida vem despontando também na produção de enzimas. As proteases são o grupo de enzimas mais exploradas comercialmente, no entanto o uso de Basidiomicetos como produtores de proteases ainda é um tema pouco explorado. O objetivo deste trabalho foi avaliar o crescimento micelial, bem como investigar a produção e caracterizar parcialmente proteases extracelulares de Pleurotus ostreatoroseus DPUA 1720 em diferentes resíduos agroindustriais, selecionar uma mistura para produção dos basidiomas e verificar sua qualidade microbiológica e valor nutricional. As culturas foram preparadas em ágar batata dextrose acrescido de extrato de levedura 0,5% (p/v). O crescimento micelial vertical e a produção de proteases de P. ostreatoroseus foram realizados em resíduos agroindustriais (semente de açaí, serragem, casca de cupuaçu, farelo de arroz, casca e coroa de abacaxi) durante 15 dias, sob duas condições de cultivo (presença e ausência de luz). A produção do basidioma foi realizada no substrato que apresentou crescimento micelial satisfatório e micélio vigoroso. A partir desse bioprocesso foi avaliada a formação e desenvolvimento dos primórdios, tempo total de cultivo, eficiência biológica, produtividade, taxa de produção, perda de matéria orgânica, qualidade microbiológica e valor nutricional dos basidiomas. P. ostreatoroseus DPUA 1720 cresceu em todos os resíduos agroindustriais testados, também servindo como fontes para a produção de proteases. Em casca de cupuaçu adicionado de farelo de arroz o micélio foi fortemente vigoroso e o crescimento micelial satisfatório, por isso selecionado para produção de P. ostreatoroseus DPUA 1720. Nas condições experimentais a atividade proteolítica foi determinada nos extratos brutos provenientes dos substratos miceliados do crescimento micelial vertical com máxima atividade proteolítica (7,89 U/mL) em casca de cupuaçu adicionado de farelo de arroz na presença de luz. Este substrato foi o mais eficiente para a produção das proteases com atividade em pH 6,0 e temperatura ótima a 40˚C. Os basidiomas apresentaram ausência de contaminantes, baixo teor de lipídios, alto teor de fibras e proteínas, macro e microminerais, aminoácidos essenciais e não essenciais, podendo assim ser inserido na alimentação como um alimento saudável e nutritivo.

Made available in DSpace on 2015-04-11T13:55:47Z (GMT). No. of bitstreams: 1 Marcus Vinicius Lopes de Lima.pdf: 1036854 bytes, checksum: ac6f00a175ea31a35d39d2469140ccaf (MD5) Previous issue date: 2012-08-31 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The dark-brown spot is a disease that occurs in the leaves of the tomato tree and is caused by the fungus Corynespora cassiicola. The fungus is considered cosmopolitan and nonspecific because of the wide host range and geographical distribution. Due to the absence of resilient and grow commercial chemicals registered in Brazil to control the disease the same is done with the use of alternative products so healing. This paper reports the in vitro antifungal effect of the ethanol extract phases and volatile oil from Piper aduncum and prophylactic and curative effect of aqueous extract of P. aduncum in tomato seedlings. The aqueous extract was obtained by macerating 300 g of fresh leaves in 2 L of water, ethanol extract by means of cold maceration of leaves with ethanol, the essential oil obtained by the method of hydrodistillation of the dry leaves, the the hexane, chloroform, N-butanol and hydroalcoholic through the fractionation of the ethanol extract by the process of liquid-liquid partition. For in vitro assays were performed in petri dishes, the antifungal effect of the ethanol extract phases and volatile oil of P. aduncum on mycelial growth, and germination of conidia blades while in vivo via inoculation of conidia suspension of 104 conidia mL-1 in tomato seedlings of the cultivar Santa Cruz Kada, the analyzes were done before and after treatment with aqueous extract, evaluations of prophylactic and curative effect, respectively. The volatile oil of P. aduncum showed no inhibition on the mycelial growth of C. cassiicola concentrations tested. The ethanol extract, the hexane and chloroform showed antifungal effect in 10000 μg.mL-1 concentration on mycelial growth and spore germination. The minimum inhibitory concentration on the mycelial growth was in 2000 μg.mL-1 of the hexane phase, this same concentration was found for the germination of conidia in the ethanol extract. The aqueous extract of P. aduncum the test of curative effect at dosages 1:1 and 1:2, showed significant effect in reducing the severity of the disease. The calculation of AUDPC confirming curative effect at all doses tested. In testing the prophylactic aqueous extract showed no effectiveness in controlling the disease / A mancha alvo do tomateiro é uma doença que ocorre nas folhas e é causada pelo fungo Corynespora cassiicola. O fungo é considerado cosmopólita e inespecífico devido à ampla gama de hospedeiros e distribuição geográfica. Devido à inexistência de cultivarem comerciais resistentes e produtos químicos registrados no Brasil para o controle da doença, o mesmo é feito com uso de produtos alternativos de forma curativa. Este trabalho relata o efeito antifúngico in vitro do extrato etanólico, fases e óleo volátil de Piper aduncum e o efeito curativo e profilático do extrato aquoso de P. aduncum em mudas de tomateiro. O extrato aquoso foi obtido por meio da maceração de 300 g de folhas verdes em 2 L de água; O extrato etanólico, por meio da maceração a frio de folhas secas com etanol; o óleo volátil obtido pelo método da hidrodestilação das folhas secas; as fases hexânica, clorofórmica, N-butanólica e hidroalcóolico por meio do fracionamento do extrato etanólico pelo processo de partição líquido-líquido. Para as análises in vitro, foram realizadas em placas de petri o efeito antifúngico do extrato etanólico, fases e óleo volátil de P. aduncum sobre o crescimento micelial, e em lâminas a germinação dos conídios, enquanto que, in vivo, via inoculação de suspensão de inóculo na concentração de 104 conídios.mL-1 em mudas de tomateiro do cultivar Santa Cruz Kada, as análises foram feitas antes e após tratamento com extrato aquoso, nas avaliações do efeito curativo e profilático, respectivamente. O óleo volátil de P. aduncum não apresentou nenhuma inibição sobre o crescimento micelial de C. cassiicola nas concentrações testadas. O extrato etanólico, fases hexânica e clorofórmica apresentaram efeito antifúngico na concentração 10000 µg.mL-1 sobre o crescimento micelial e germinação dos conídios. A concentração inibitória mínima sobre o crescimento micelial foi em 2000 µg.mL-1 da fase hexânica, nesta mesma concentração foi encontrado para a germinação dos conídios no extrato etanólico. O extrato aquoso de P. aduncum no teste de efeito curativo nas dosagens 1:1 e 1:2, apresentaram efeito significativo na redução da severidade da doença. O cálculo da AACPD confirma o efeito curativo em todas as dosagens testadas. No teste profilático o extrato aquoso não apresentou nenhuma efetividade no controle da doença

Made available in DSpace on 2014-06-11T19:28:30Z (GMT). No. of bitstreams: 0 Previous issue date: 2006-05-15Bitstream added on 2014-06-13T20:58:17Z : No. of bitstreams: 1 rosa_j_me_jabo.pdf: 154567 bytes, checksum: 0d2897a42007e37a9a5f314b75f0f0f0 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA) / Objetivou-se o ajuste de metodologia e seleção de genótipos de guandu para resistência a Macrophomina phaseolina a partir de material obtido pela Embrapa Pecuária Sudeste, e verificar o desenvolvimento micelial e esporulação do fungo em meios de cultura. O trabalho foi conduzido em casa de vegetação na UNESP/Jaboticabal no período de agosto de 2004 a dezembro de 2005. Para o ajuste de metodologia e seleção de genótipos resistentes ao fungo as sementes foram submetidas a escarificação com lixa d'água e inoculação artificial através do método de exposição das mesmas ao patógeno por diferentes períodos, que variaram de O a 72 horas. Foram avaliadas porcentagem de plantas sobreviventes e massa fresca. Já para o crescimento micelial e esporulação do fungo foi utilizado o método de sobreposição de discos de diferentes hospedeiros no meio de cultura. A escarificação das sementes contribuiu para a penetração do fungo nas mesmas o período de 24h de exposição das sementes ao fungo são suficientes para detectar diferenças no grau de resistência dos genótipos. Os genótipos mais resistentes são g167-97, g124-95, g27-94, g40-95, g154-95, g127-97 e g9m-97, e os mais suscetíveis são g48-95, g123-95, g8-95, g168-99 e g1m-95. A sobreposição de discos foliares de guandu em meio BDA e folha de papel de filtro em meio sojinha proporcionam um incremento na esporulação de M. phaseolina. / This work had the objective of determining the best schedule for artificial inoculation and select pigeon pea genotypes resistant to Macrophomina phaseolina in material obtained by Embrapa Pecuária Sudeste, and verify the mycelial growth and sporulation of the fungi in middle of culture. The work were carried in greenhouse at the UNESP/Jaboticabal, from August 2004 to December 2005. For the methodology and selection adjustment of resistant genotypes to the fungi the seeds were submitted scarified with water sandpaper and artificial inoculation the seeds were the contact method to fungi for different periods, which varied from O to 72 hours. They were evaluated percentage of surviving plants and fresh mass. For the mycelial growth and sporulation of the fungi was used the superposition of disks method of different hosts in the middle of culture. The scarified of the seeds contributed for penetration of the fungi at the seeds; the period of 24h of contact of the seeds to the fungi enough to detect differences in the resistance degree ofthe genotypes. The genotypes g167-97, g124-95, 927-94, g40-95, g154-95, g127-97 and g9m-97 were found to be the most resistant and most susceptible were g48-95, g123-95, g8-95, g168-99 and g1m-95. The treatment with superposition of the leaf disks of pigeon pea in BDA and disks of filter paper in middle of soybean extract were the treatments that provided better sporulation levei in the conditions of that experiment were half.

CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / Estudos com fungos micorrÃzicos arbusculares tentam elucidar a contribuiÃÃo desses microrganismos no transporte de compostos sinalizadores entre plantas, uma vez que, eles formam uma rede micelial subterrÃnea que conecta as plantas e sÃo capazes de translocar substÃncias entre plantas vizinhas. O objetivo deste estudo foi avaliar a contribuiÃÃo dos fungos micorrÃzicos arbusculares na induÃÃo à resistÃncia do tomateiro a Meloidogyne incognita raÃa 2. O experimento foi realizado em casa de vegetaÃÃo e o delineamento experimental adotado foi o inteiramente casualizado (DIC), composto por 4 tratamentos e 5 repetiÃÃes, totalizando 20 parcelas. Cada parcela constituiu-se por um sistema inicial de vaso duplo conectado (VDC), contendo uma planta em cada lado do vaso, onde uma das plantas foi denominada de emissora (E) e a outra de receptora (R). Os tratamentos foram oriundos da combinaÃÃo entre os vasos com plantas emissoras com e sem micorriza, respectivamente (EM+ e EM-), conectados a vasos com plantas receptoras com e sem micorriza (RM+ e RM-). O experimento foi realizado em duas etapas, fase I e fase II. Iniciou-se a fase I com a introduÃÃo do inÃculo de nematÃide (4000 ovos e J2 M. incognita raÃa 2) apenas nos lados dos vasos contendo as plantas emissoras, com e sem micorrÃza (EM+ e EM-), tendo estas permanecido em contato com os nematÃides durante 45 dias. ApÃs esse perÃodo, procedeu-se a separaÃÃo dos vasos duplos conectados. A fase II teve inÃcio apÃs a separaÃÃo dos vasos e adiÃÃo do inÃculo do nematÃide nas plantas receptoras, permanecendo 45 dias em contado com os nematÃides em casa de vegetaÃÃo. Os resultados mostraram que as plantas emissoras inoculadas com micorrizas foram mais susceptÃveis ao parasitismo por M. incognita raÃa 2, apresentando menor desenvolvimento da planta e maior susceptibilidade ao nematoide. As plantas receptoras que estiveram em contato com as plantas emissoras com micorriza (EM+) no perÃodo de prÃ-condicionamento apresentaram melhor crescimento e menor susceptibilidade ao M. incognita revelando, dessa forma, que foram estimuladas durante a fase I, a acionar seu mecanismo de defesa contra o patÃgeno. / Studies mycorrhizal fungi try to elucidate the contribution of microorganisms in the transport of signaling between plants compounds, since they form a network that connects the underground mycelial and plant substances are able to translocate between neighboring plants. The aim of this study was to evaluate the contribution of mycorrhizal fungi in inducing resistance of tomato to Meloidogyne incognita race 2. The experiment was conducted in a greenhouse and the experimental design was a completely randomized design, consisting of 4 treatments and 5 replicates, totaling 20 plots. Each plot was constituted by a dual system connected initial vessel containing a plant on each side of the vessel, where a plant has been called issuing (I) and one receiver (R).The treatments were derived from the combination of the potted issuing plants with and without mycorrhiza, respectively (IM + and IM-) connected the potted receiver plant with and without mycorrhiza (RM + and RM-). The experiment was conducted in two phases, phase I and phase II. It started with phase I the introduction of nematode inoculum (4000 eggs and J2 Meloidogyne incognita race 2) only at the sides of the pots containing the issuing plants with and without mycorrhiza (IM + and IM-), and those remained in contact with nematodes for 45 days. After this period, we proceeded to double the separation vessel connected. Phase II began after the separation vessel and addition of the nematode inoculum in receiver plants 45 days remaining in contact with the nematodes in the greenhouse. The results showed that issuing plants inoculated with mycorrhizal were more likely to parasitism by M. incognita race 2, with lower plant development and increased susceptibility to nematodes. The receiver plants that were in contact with the issuing plants with mycorrhiza (IM+) during the preconditioning showed better growth and lower susceptibility to M. incognita revealing thereby that were stimulated during Phase I, the activate mechanism of defense against the pathogen.