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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.
91

Control biológico in vitro de Botrytis cinerea (Pers) mediante el uso de hongos antagonistas, en vid (Vitis vinifera)

Memenza Zegarra, Miriam Estela January 2009 (has links)
En el cultivo de la vid, se reporta a Botrytis cinerea Pers como el hongo patógeno causante de lesiones cancrosas, necrosamiento de brotes y racimos de flores, y pudrición de frutos y semillas, que ocasionan grandes pérdidas económicas a los agricultores. El control de este patógeno se realiza hasta nuestros días con sustancias de origen químico: plaguicidas; los cuales son aplicados al follaje, a las semillas y al suelo, ocasionando problemas en el ambiente. En el presente trabajo, se colectaron 56 muestras de hojas de vid, infectadas con Botrytis cinerea Pers, en un viñedo del caserío La Huaca, en el distrito de San Benito, provincia de Contumaza, departamento de Cajamarca, durante el verano del 2006; de las cuales se aislaron e identificaron 12 cepas de Trichoderma viride. En la evaluación de la actividad antagonista de las 12 cepas de T. viride sobre B. cinerea mediante el método Precolonizado de Placas a 24° C y 28° C, se seleccionó a las cinco cepas: CH-13, CH-25, CH-30, CH-38 y CH-52 que presentaron los mayores porcentajes de área ocupada sobre el patógeno. Estas cepas presentaron actividad antagonista del tipo micoparasitismo, observándose enrollamiento y penetración de las hifas de las cepas de T. viride sobre las hifas de B. cinerea. De las cinco cepas seleccionadas de T. viride, la cepa CH-30 presentó el mayor porcentaje de área ocupada sobre B. cinerea a 24° C y 28° C con un 54.67% y 98% respectivamente. Por los resultados obtenidos, las cinco cepas nativas de Trichoderma viride pueden ser consideradas como una alternativa ecológica para su evaluación como agentes potenciales de control biológico del patógeno B. cinerea. / In the culturing of grapevine, there is reported Botrytis cinerea Pers as the fungus pathogenic causative of canker injuries, necrotizing of outbreaks and clusters of flowers, and rotting of fruits and seeds, which cause big economic losses to the farmers. The control of this pathogenic is realized actually by substances of chemical origin: pesticides; which are applied to the foliage, to the seeds and to the soil, causing environment problems. In this present work, there were collected 56 samples of leaves of grapevine, infected with Botrytis cinerea Pers, in a vineyard of The Huaca hamlet, in San Benito district, Contumaza province, Cajamarca department, during the summer of 2006; from these ones, there were isolated and identified 12 strains of Trichoderma viride. In the evaluation of the antagonist activity of these 12 strains of T. viride on B. cinerea by the method of Plates pre-colonized in 24° C and 28 °C, was selected five strains: CH-13, CH-25, CH-30, CH-38 and CH-52 that presented the major percentages of occupied area over the fungus pathogenic. These strains showed antagonist activity of mycoparasitism kind, being observed rolling and penetration of mycelium of T. viride strains on the mycelium of B. cinerea. From 5 T. viride strains selected, the CH-30 one showed the major percentage of occupied area on B. cinerea in 24° C and 28 °C with 54.67% and 98% respectively. For the results obtained, five native strains of Trichoderma viride can be considered as an ecological alternative for its evaluation as potential agents of biological control of the pathogenic B. cinerea.
92

Social modulation of adult brain cell proliferation: influence of sex and gonadal hormones

Almli, Lynn Marie 14 October 2009 (has links)
Environmental factors are known to have far reaching effects on nervous system function, and in the adult brain, it is clear that a wide range of environmental stimuli modulate cell proliferation and survival (e.g., neurogenesis). This project investigated whether social stimulation and concomitant changes in gonadal hormones can influence the proliferation of new cells in the adult brain. The adult green treefrog (Hyla cinerea)was used as the model system; studying the courtship behavior of the highly social treefrog affords a direct, quantifiable way to measure the effects of acoustic social cues and hormonal intervention on adult brain cell proliferation. Using immunohistochemistry techiques, endocrinological manipulations, and socially-relevant acoustic stimulus presentations, I report that social cues modulate cell proliferation in the brains of adult male and female H. cinerea. I first mapped the distribution of proliferative areas in the adult treefrog brain using 5-bromo-2′- deoxyuridine (BrdU) labeling. I then exposed naturally-cycling male and female treefrogs to random tones or a recording of a natural H. cinerea chorus for ten days during the breeding season. I found that male and female treefrogs that heard their conspecific chorus exhibited increased brain cell proliferation compared to animals that heard random tones. Moreover, this modulation was region-specific and occurred in those regions which reflected their presumed involvement in reproductive physiology and behavior: the preoptic area (POA) and the infundibular hypothalamus (IF). To determine the involvement of gonadal hormones in cell proliferation with and without social stimulation, I gonadectomized and implanted male and female H. cinerea with blank or steroid-filled implants. After exposing the treefrogs to the same acoustic conditions as above, I discovered that social modulation of adult cell proliferation can occur without the influence of gonadal hormones (i.e., androgens in the male and estrogen in the female). Furthermore, the results revealed that neither hormone was neurotrophic and in fact, chronically-elevated estrogen levels decreased cell proliferation in the female POA and IF. Together, these results indicate that the reception of acoustic social cues increases cell proliferation in brain regions mediating sexual behavior and endocrine regulation; furthermore, this modulation occurs in a sexually-differentiated fashion without gonadal hormone influence. / text
93

Synergistic effects of mixtures of fungicides and medicinal plant extracts against Botrytis cinerea

Vries, Filicity Ann January 2008 (has links)
<p>We hypothesize that South African medicinal plants contain compounds that can act in synergism with synthetic antifungal compounds. Four fungicides - Sporekill&trade / , Rovral&trade / , Terminator&trade / and Teldor&trade / at doses 0.1, 0.2, 0.4 and 0.8 mL L-1 and plant species Galenia africana, Elytropappus rhinocerotis and Tulbaghia violacea were tested aloneand in different combinations for their potency (efficacy) on radial growth inhibition of Botrytis cinerea strains on potato dextrose plates. Four doses of plant extract for each of the respective plant species were used. A total of 48 combinations were tested for each strain. Mixtures of plant extracts were far more effective in controlling strains compared to the individual components alone, representing significant levels of in vitro synergistic interactions. Combinations of these components represent an attractive future prospect for the development of new management strategies for controlling B. cinerea. Since the in vitro tests of these mixtures showed inhibitory activity, the mixtures were tested for activity in assays on Granny Smith apples. In vitro tests can be used to screen mixtures to obtain information on their inhibitory activity on a pathogen, however, the environmental conditions of the fruit and the ability of the pathogen to grow into the fruit cannot be simulated in vivo. A series of two-fold doses of medicinal plant extracts were combined with fungicides to conduct decay inhibition studies. The incidence of gray mold was significantly reduced by mixtures of plant extracts and fungicides. Under conditions similar to those in commercial storage, a drench treatment with G. africana and Rovral&trade / significantly (p=0.05) inhibit gray mold on the apples and was more effective than the plant extract and fungicide alone. The treatments exerted synergistic effects and were markedly better than the components applied alone. The wound colonization assay was used for optimal decay control. In a drench, much higher volumes of the treatments are used to ensure that the components of the suspension are deposited evenly over the entire fruit surface. Drenching of fruit to apply other chemicals is an established practise in the pome (fleshy) fruit industry, and simplifies the commercial application of the mixtures, as no additional infrastructure at commercial packing houses will be required. This approach not only makes it possible to reduce fungicide concentrations while maintaining adequate decay control, but also ensures a reduction of the chemical residue on the fruit.</p>
94

Use of a monoclonal antibody to detect gray mold (Botrytis cinerea) in strawberry

Mohr, Alexandra. January 2001 (has links)
Gray mold, caused by Botrytis cinerea is the major cause of postharvest loss in strawberries. Detection of flower and fruit infections enables producers to make intelligent management decisions. A plate-trapped ELISA protocol using a Botrytis-specific monoclonal antibody (BC-12.CA4) was developed for the detection of Botrytis cinerea in strawberry flower receptacles and red fruits. Horseradish peroxidase, was chosen as enzyme conjugate because it gave lower background absorbance in disease-free samples. B. cinerea reference antigen (RAg) was isolated from strawberry. BC-12.CA4 was very sensitive to the RAg, detecting up to 6 mug/ml of RAg when mixed with strawberry extracts. The MAb did not show any reaction to Rhizopus sp., Mucor sp. and Penicillium sp. associated with strawberry. B. cinerea could be detected in receptacles two days after inoculation. Treatment of inoculated receptacles with paraquat speeded-up detection. Inoculated red fruit infection could be detected after three days of incubation. Disease in commercially-produced receptacles and red fruits were assessed visually and by ELISA. The ELISA detected B. cinerea in 95% of commercial flower samples, whereas the traditional visual method detected only 50 to 70%. No dramatic differences between methods were found for red fruits.
95

Synergistic effects of mixtures of fungicides and medicinal plant extracts against Botrytis cinerea

Vries, Filicity Ann January 2008 (has links)
<p>We hypothesize that South African medicinal plants contain compounds that can act in synergism with synthetic antifungal compounds. Four fungicides - Sporekill&trade / , Rovral&trade / , Terminator&trade / and Teldor&trade / at doses 0.1, 0.2, 0.4 and 0.8 mL L-1 and plant species Galenia africana, Elytropappus rhinocerotis and Tulbaghia violacea were tested aloneand in different combinations for their potency (efficacy) on radial growth inhibition of Botrytis cinerea strains on potato dextrose plates. Four doses of plant extract for each of the respective plant species were used. A total of 48 combinations were tested for each strain. Mixtures of plant extracts were far more effective in controlling strains compared to the individual components alone, representing significant levels of in vitro synergistic interactions. Combinations of these components represent an attractive future prospect for the development of new management strategies for controlling B. cinerea. Since the in vitro tests of these mixtures showed inhibitory activity, the mixtures were tested for activity in assays on Granny Smith apples. In vitro tests can be used to screen mixtures to obtain information on their inhibitory activity on a pathogen, however, the environmental conditions of the fruit and the ability of the pathogen to grow into the fruit cannot be simulated in vivo. A series of two-fold doses of medicinal plant extracts were combined with fungicides to conduct decay inhibition studies. The incidence of gray mold was significantly reduced by mixtures of plant extracts and fungicides. Under conditions similar to those in commercial storage, a drench treatment with G. africana and Rovral&trade / significantly (p=0.05) inhibit gray mold on the apples and was more effective than the plant extract and fungicide alone. The treatments exerted synergistic effects and were markedly better than the components applied alone. The wound colonization assay was used for optimal decay control. In a drench, much higher volumes of the treatments are used to ensure that the components of the suspension are deposited evenly over the entire fruit surface. Drenching of fruit to apply other chemicals is an established practise in the pome (fleshy) fruit industry, and simplifies the commercial application of the mixtures, as no additional infrastructure at commercial packing houses will be required. This approach not only makes it possible to reduce fungicide concentrations while maintaining adequate decay control, but also ensures a reduction of the chemical residue on the fruit.</p>
96

The structure-function relationship of the lung of the Australian sea lion, Neophoca cinerea / by Anthony Nicholson

Nicholson, Anthony Ian January 1984 (has links)
Bibliography: leaves 193-224 / xvi, 224 leaves, [1] plate : ill. (1 col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Pathology, 1984
97

Human impacts on Australian sea lions, Neophoca cinerea, hauled out on Carnac Island (Perth, Western Australia): implications for wildlife and tourism management

jporsini@bigpond.net.au, Jean-Paul Orsini January 2004 (has links)
Over the last 15 years, pinniped tourism has experienced a rapid growth in the Southern Hemisphere, and particularly in Australia and New Zealand where at least four sites attract more than 100,000 visitors per year. Tourism focused on the Australian sea lion (Neophoca cinerea), a protected species endemic to Australia, occurs in at least nine sites in South Australia and Western Australia. Australian sea lions haul out on several offshore islands in the Perth region. Carnac Island Nature Reserve is one of the main sites where people can view sea lions near Perth, either during recreational activities or on commercial tours. This study sought: (1) to investigate the potential impact of human visitors on Australian sea lions hauled out on Carnac Island, (2) to consider implications of the results for the management of Carnac Island Nature Reserve, and (3) to examine under which conditions tourism and recreation around sea lions can be sustained in the long term. Sea lion numbers, rate of return to the site, behavioural response to human presence and incidents of disturbances of sea lions by visitors were recorded over a period of four months on Carnac Island. A survey of 207 visitors was also carried out. Findings indicated that there were two main types of human impacts on the sea lions: • A specific state of sea lion vigilance induced by low level, but ongoing, repetitive disturbances from human presence, sustained at various approach distances ranging to more than 15 m, vigilance that is different from the behaviour profile observed in the absence of human disturbance, • Impacts resulting from incidental direct disturbances of sea lions by visitors from inappropriate human recreational activities or from visitors trying to elicit a more ‘active’ sea lion response than the usual ‘sleeping or resting’ behaviour on display; these impacts included sea lions retreating and leaving the beach, or displaying aggressive behaviour. Impacts on sea lions from these disturbances may range from a potential sea lion physiological stress response to sea lions leaving the beach, a reduction in the time sea lions spend hauling out, and, in the longer term, the risk of sea lions abandoning the site altogether. Repeated instances of visitors (including unsupervised young children) approaching sea lions at very short distances of less than 2.5 m represented a public safety risk. Results also indicated that (1) the numbers of sea lions hauled out and their rate of return to the beach did not appear to be affected by an increase in the level of human visitation (although longer-term studies would be required to confirm this result); and (2) there appeared to be a high turnover rate of sea lions at the site from day to day, suggesting that there are frequent arrivals and departures of sea lions to and from Carnac Island. The visitor survey indicated that many visitors to Carnac Island had a recreational focus that was not primarily directed towards sea lion viewing (‘incidental ecotourists’). Although many visitors witnessed incidental disturbance caused by humans to sea lions, they did not seem to recognise that they themselves could disturb sea lions through their mere presence. Visitors also seemed to have a limited awareness of the safety risk posed by sea lions at close range. Visitors expressed support for the presence of a volunteer ranger on the beach and for more on-site information about sea lions. Finally, visitors indicated that they greatly valued their sea lion viewing experience. It is anticipated that the continued increase in visitation to Carnac Island from recreation and from tourism will result in intensified competition for space between humans and sea lions. Long-term impacts of human disturbances on sea lions are unknown, but a physiological stress response and/or the abandonment of haulout sites has been observed in other pinniped species. The findings of this study highlight the need to implement a long-term strategy to reduce disturbance levels of sea lions by visitors at Carnac Island to ensure that tourism and recreation around sea lions can be sustained in the long term. Recommendations include measures to control visitor numbers on the island through an equitable allocation system between various user groups, the development of on-site sea lion interpretation and a public education and awareness program, the setting up of a Sea Lion Sanctuary Zone on the main beach, ongoing monitoring of sea lion and visitor numbers and other data, and a system of training and accreditation of guides employed by tour operators.
98

Biological control of grey mould in Swedish forest nurseries /

Capieau, Kristof, January 2004 (has links) (PDF)
Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniversitet, 2004. / Härtill 4 uppsatser.
99

Pressões hiperbáricas no controle de mofo cinzento e de mancha de Alternaria na pós-colheita de tomate Débora /

Palaretti, Vanessa Voigt January 2018 (has links)
Orientador: Ben-Hur Mattiuz / Resumo: As doenças fúngicas são as principais causas de perdas na pós-colheita do tomate, e são controladas por manejo cultural e fungicidas aplicados na pré-colheita. O tratamento hiperbárico na pós-colheita é um métodos físico, com potencial uso comercial na redução da deteriorização por fungos. Neste trabalho, a eficiência das pressões hiperbáricas para controlar o desenvolvimento das podridões de Botrytis cinerea e Alternaria sp. in vitro e em tomates ‘Débora’ foram avaliadas, bem como a atividade das enzimas antioxidantes e as relacionadas a defesa do vegetal. Os experimentos foram realizados em um sistema de pressão hiperbárica do Laboratório de Tecnologia Pós-colheita da FCAV-UNESP, Câmpus de Jaboticabal, utilizando as pressões de 100 (controle), 200, 400, 600 e 800 kPa à temperatura de 23±1°C, durante 3 e 6 dias. No ensaio in vitro as placas com os fungos permaneceram nas pressões e depois foram incubadas até que a colônia do controle atingisse a borda. No experimento in vivo, tomates inoculados com os fungos foram mantidos por 3 e 6 dias sob o tratamento nas pressões, com posterior armazenamento por mais 2 e 4 dias em condição de ambiente (23 °C, 50% UR, 100 kPa) para simular a comercialização. Avaliou-se o crescimento micelial, a taxa de germinação dos conídios dos fungos, incidência e severidade das podridões nos frutos, o metabolismo antioxidante (teor de licopeno e polifenóis totais) e a atividade das enzimas relacionadas à defesa dos tomates (peroxidase (POD), fenilalan... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Fungal rots are one of the major causes of postharvest losses in tomatoes, and they are controlled by cultural management and fungicidal applied in preharvest. The postharvest hyperbaric treatment is a physical method that it have potential to be used in commercial for reducing fungal decay. In this work, the efficiency of hyperbaric pressures to control rot development of Botrytis cinerea and Alternaria sp. in vitro and ‘Debora’ tomatoes were evaluated, also the activity of antioxidant and defense-related enzymes.The experiments were carried out in a hyperbaric pressure system at FCAV-UNESP Postharvest Technology Laboratory, Campus de Jaboticabal, using the pressures of 100 (control), 200, 400, 600 and 800 kPa at a temperature of 23 ± 1 ° C for 3 and 6 days. In vitro assay the Petri dishes with the fungi were kept at pressures after they were incubated until the control colony reached the edge. In vivo assay, tomatoes inoculated with the fungus were kept at 3 and 6 days under the treatment pressures, after they were stored for more 2 and 4 days at ambient conditions (23 °C, 50% RH, 100 kPa) to simulate the commercialization. It was evaluated the mycelial growth, germination rate of fungal conidia, incidence and severity of fruit rot, antioxidant metabolism (lycopene content and total polyphenols) and activity of defence-related enzymes (eroxidase (POD), phenylalanine ammonia-lyase (PAL), β 1,3 glucanase (GLU), superoxide dismutase (SOD) and catalase (CAT)). The hyperbaric pr... (Complete abstract click electronic access below) / Doutor
100

Determinación de la ocurrencia de infecciones por Botrytis cinerea Pers. en peras cv. Packham's Triumph post floración / Determination of the occurrence of post flowering infections by Botrytis cinerea Pers. in pears cv. Packham’s triumph

Bustamante Álvarez, Marcelo Ignacio January 2015 (has links)
Memoria para optar al Título Profesional de Ingeniero Agrónomo / Botrytis cinerea Pers. causa niveles importantes de pudrición, los que pueden superar el 10% en peras de exportación en Chile, principalmente en la variedad Packham’s Triumph. La enfermedad postcosecha más importante producida por B. cinerea en peras almacenadas en frío corresponde a la pudrición calicinal, cuyo control se realiza en floración, período en que el hongo produce infecciones latentes que se manifiestan en pudrición tras la madurez de la fruta. En años con primaveras húmedas se ha observado un aumento de la incidencia de la enfermedad, lo cual ha generado cuestionamientos acerca de los tratamientos de control e incertidumbre sobre la capacidad del patógeno de infectar los frutos durante su crecimiento. Los objetivos del presente estudio fueron determinar la ocurrencia de infecciones en campo durante el período de crecimiento de frutos bajo condiciones artificiales de alta humedad con y sin inoculación del patógeno, y determinar el nivel de infección en precosecha para evaluar la efectividad de las medidas de control realizadas por los productores en dos huertos comerciales de la zona central de Chile. En uno de los huertos estudiados se determinó que las inoculaciones lograron generar infecciones en el período de crecimiento de frutos, lo que permite concluir que el patógeno efectivamente puede infectar peras cv. Packham’s Triumph durante el crecimiento de los frutos. Por otro lado, el patógeno fue recuperado desde la cavidad calicinal de fruta no inoculada en crecimiento en ambos huertos, observándose también pudrición calicinal en postcosecha, lo que sería consecuencia de la inefectividad de las aplicaciones de fungicidas realizadas en floración por los productores. Este trabajo establece una base para la realización de estudios en campo en pudrición calicinal de perales en Chile. / Botrytis cinerea Pers. causes significant levels of postharvest decay that may be over 10% in pear fruit in Chile, especially in the cultivar Packham's Triumph. Calyx-end rot is the most important postharvest disease caused by B. cinerea in stored pears, and its control is achieved in the flowering period, when the fungus produces latent infections that manifest in fruit decay after ripening. It has been observed that there is an increased incidence of the disease in years with humid and rainy conditions during spring and summer, which has raised questions about control treatments and pathogen's ability to infect fruit during its growth under these conditions. The objectives of this study were to determine the occurrence of infections in the orchard during fruit growth under artificial high humidity conditions with and without pathogen inoculation, and to determine the level of preharvest infection in order to evaluate the efficacy of control measures taken by the growers in two commercial orchards of central Chile. In one of the studied orchards, inoculations resulted in infections during fruit growth, leading to the conclusion that the pathogen can effectively infect Packham's Triumph pears during this period. Moreover, the pathogen was isolated from the calyx cavity of non-inoculated fruit during the growth period, and postharvest calyx-end decay was also observed, which would indicate the inefficacy of fungicide applications performed by the growers. This work provides basic information for further field studies on calyx-end rot of pears in Chile.

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