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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.
21

Biologia, Diagn?stico morfol?gico e molecular da infec??o experimental e natural de Babesia equi (Laveran, 1901) em Boophilus microplus (Canestrini, 1887). / Biology, Morphologic and molecular diagnosis of the experimental and natural infection of Babesia equi (Laveran, 1901) in Boophilus microplus (Canestrini, 1887).

Fernandes, K?tia Roberta 26 February 2007 (has links)
Made available in DSpace on 2016-04-28T20:16:24Z (GMT). No. of bitstreams: 1 2007- Katia Roberta Fernandes.pdf: 2143619 bytes, checksum: 6ff7127f4642317cf1f53d7aceb93f1f (MD5) Previous issue date: 2007-02-26 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / The aim of the present study was to evaluate the natural and experimental infection of B. equi in nymphs and adult Boophilus microplus using optical microscopy and molecular analysis. The experimental infection was observed in nymphs, males and females of B. microplus fed on equines chronically infected with B. equi and in non fed larvae and eggs. For the experiments two equines, of not defined breed, proven to be infected with B. equi were used. The animals were infested with B. microplus larvae of generation F4 obtained from a laboratory maintained population, known to be free of Babesia spp. infection. Daily collections of ticks were realized using as starting point the ecdisys to nymph state. After the collection the hemolymph was examined and the intestine and salivary glands were dissected, smashed on glass slides for microscopy, methanol treated and stained with Giemsa. There were dissected 860 specimens (432 nymphs, 280 females and 148 males). The dissected salivary glands were divided into two parts. The first one was smashed on microscopy glass slides, stained and examined by optical microscopy for morphologic analyses. From the second part was realized DNA extraction and PCR with specific primers for the 18S rRNA. On optical microscopy of nymph hemolymph was possible to be observed the presence of kinetes with claviform aspect characteristic for the genus Babesia. In the salivary glands of B. microplus nymphs the morphology and the sequence of developmental stages of B. equi were observed initiating on day 4 after ecdysis, being possible to see in acinary cells the formation of sporoblasts and ovoid sporozoites measuring 1.5 μm of diameter and elongated sporozoites with 3.8 to 5.2μm of length and 0.8 to 1.5 μm of width. The PCR confirmed the presence of B. equi in DNA samples extracted from salivary glands of nymphs, male and female ticks as well as in larvae and eggs. To evaluate the natural infection were collected nymphs and adult B. microplus from two equines naturally infested by these ticks and naturally infected with B. equi. These horses were originated from Seropedica city in the state of Rio de Janeiro. There were dissected 324 specimens (145 nymphs, 138 females and 41 males). The proceedings with the salivary glands were identical to the previously described for the experimental infection. Of the salivary glands submitted to PCR, 70% showed to be infected with B. equi. Microscopical analysis of the salivary glands revealed the presence of sporoblast stages and the development of elongated sporozoites in acinary glands. The morphologic, morphometric and molecular analysis confirmed the experimental and natural infection of the salivary glands of nymphs and adult B. microplus with B. equi. The results of the present study show the ability of B. equi to develop in this tick species. The detection of B. equi DNA in eggs and larvae also suggests the possibility of transovarian transmission in B. microplus. The results allow to consider the tick B. microplus as a potential biologic vector of B. equi in horses from the studied region. / Este trabalho teve como objetivo avaliar a infec??o natural e experimental de Babesia equi em ninfas e adultos de Boophilus microplus por meio de microscopia ?ptica e an?lise molecular. A infec??o experimental foi observada a partir de ninfas, machos, f?meas, ovos e larvas n?o alimentadas de B. microplus alimentados em equinos com infec??o cr?nica por B. equi. Para a realiza??o do experimento foram utilizados dois eq?inos, mesti?os, com infec??o por B. equi. Os animais foram infestados com larvas de B. microplus de gera??o F4 obtidas de col?nia mantida em laborat?rio e livres de infec??o por Babesia spp. A partir da ecdise para ninfa foram realizadas coletas di?rias. Ap?s a coleta foram realizados os exames de hemolinfa e extra??o do intestino e das gl?ndulas salivares os quais foram macerados em l?minas de vidro para microscopia, fixados em metanol e corados com Giemsa. As gl?ndulas salivares dissecadas foram divididas em duas partes. A primeira parte foi macerada em l?minas de vidro para microscopia, corada com corante Giemsa e observada em microsc?pio ?tico para an?lise morfol?gica. A segunda parte foi realizada a extra??o de DNA, sendo submetida a PCR com primers especif?cos para o gene 18S rRNA para B. equi. Foram dissecados 860 esp?cimes (ninfas= 432; f?meas= 280 e machos= 148). Na microscopia ?ptica foi poss?vel observar nas hemolinfas das ninfas a presen?a de cinetos com aspecto claviforme t?picos do g?nero Babesia. Nas gl?ndulas salivares, a morfologia e a seq??ncia dos est?gios de desenvolvimento de B. equi das ninfa s de B. microplus, foram observadas a partir do 4? dia ap?s ecdise, sendo poss?vel observar nos ?cinos celulares a forma??o de esporoblastos e de esporozo?tas ov?ides medindo 1,5 μm de di?metro e alongados medindo 3,8 a 5,2μm de comprimento e 0,8 a 1,5μm de largura. A rea??o em cadeia de polimerase (PCR) confirmou a presen?a de B. equi em DNA de gl?ndulas salivares extra?das de ninfas, machos, f?meas, assim como dos ovos e larva. A infec??o natural foi observada a partir de ninfas e adultos de B. microplus coletados de dois eq?inos naturalmente infestados e comprovadamente infectados por B. equi, procedentes do munic?pio de Serop?dica, Rio de Janeiro. Foram dissecados 324 esp?cimes (ninfas= 145, f?meas= 138 e machos= 41). O processamento das gl?ndulas salivares dissecadas foi semelhante ao descrito para infec??o experimental. Das gl?ndulas salivares submetidas a PCR, 70% apresentaram resultados positivos para B. equi. As an?lises por microscopia ?ptica das gl?ndulas salivares das ninfas e dos adultos revelaram a presen?a nos ?cinos celulares os est?gios de esporoblastos e o desenvolvimento de esporozo?tas alongados. As an?lises morfol?gicas, morfom?tricas e moleculares confirmaram a infec??o experimental e natural das gl?ndulas salivares de ninfas e adultos de B. microplus por B. equi. Os resultados deste estudo demonstram a capacidade de multiplica??o de B. equi em gl?ndulas salivares de ninfas e adultos de B. microplus. A detec??o de DNA de B. equi em ovos e larvas de B. microplus tamb?m sugere a possibilidade da transmiss?o transovariana nesta esp?cie de carrapato. Estes resultados sugerem que o carrapato B. microplus ? vetor biol?gico de B. equi na regi?o estudada.
22

Op hom die groot hosannas : enkele aspekte van die modern Christelike poësie in Afrikaans

Bosman, Maria Elizabeth January 1989 (has links)
This study is concerned with modern Christian poetry in Afrikaans. Afrikaans poetry, which initially carried the clear stamp of the Afrikaner's Calvinistic view of life, gradually assumed a new image to the extent that it could no longer be recognised as religious and specifically Calvinistic poetry. To the contrary, modern Afrikaans Christian poetry is the expression of a contemporary conceptualisation of the very same gospel. The occasional violent reaction especially of conservative institutions to so called "unchristian" modern poetry in Afrikaans during the past three decades, has prompted this study which attempts to illustrate that modern Afrikaans poetry still exhibits a strong Christian element. The essential qualities of contemporary Christian poetry in Afrikaans are illustrated in the discussion of the works of particular leading Afrikaans poets. Chapter 3 attempts to indicate a transitional stage between traditional and modern Christian poetry by means of an overview of the latest tendencies and approaches, with brief references to the recent poetry of the Louws, the poetry of Peter Blum as the initial exponent of the poetry of the Sixties, and the poetry of Ina Rousseau. The work of Sheila Cussons, eminent Roman Catholic (and thus also Christian) poet who is probably the most impressive contemporary exponent of metaphysical/mystic poetry in Afrikaans, is discussed in chapter 4. Chapter 5 illustrates the traditional Calvinistic Christian point of view and Christian experience as represented in the poetry of I.L. de Villiers. The poetification of the ministry adds new dimension to religions poetry in Afrikaans. Chapter 6 constitutes a discussion of the works of T.T . Cloete, the most significant contemporary Reformed poet in Afrikaans indicating the extent to which the many related facets embodied in his poetry consistently reflect a Christian attitude and are unified in and encompassed by the principle of Soli Deo Gloria. Chapter 7, by way of conclusion, reviews the religious poetry of Lina Spies and Petra Müller who write accessible popular poetry, nevertheless exploring interesting references. In conjunction with the poetry of Ina Rosseau, this poetry represents a contribution to modern Afrikaans religious poetry from a feminine point of view
23

Aproximaciones a una estrategia integrada para el control no contaminante de las podredumbres verde y azul en poscosecha de cítricos

Moscoso Ramírez, Pedro Antonio 20 December 2013 (has links)
Las podredumbres verde y azul causadas por los hongos patógenos Penicillium digitatum (Pers.: Fr.) Sacc y Penicillium italicum Wehmer, respectivamente, son las responsables de grandes pérdidas económicas en poscosecha de cítricos a nivel mundial. En España, las pudriciones de la fruta en poscosecha fluctúan del 3 al 6% durante una estación típica. Sin embargo, bajo condiciones favorables a la enfermedad, las pérdidas pueden alcanzar el 50%. Las podredumbres verde y azul son las enfermedades de poscosecha más importante de los cítricos en España, California y todas las áreas de producción caracterizadas por lluvias escasas en verano (Ecker y Eaks, 1989). Se han logrado avances importantes en estudios de resistencia adquirida sistémica (SAR) y resistencia sistémica inducida (ISR) tanto natural como artificial (Terry y Joyce, 2004; Tavallali et al., 2008). También se está avanzando en la evaluación de sustancias conocidas como GRAS (Generally Regarded as Safe), o en el uso del calor y la luz ultravioleta (Palou et al., 2008; Montesinos et al., 2009). Todos estos enfoques constituyen estrategias de control alternativo no contaminante. Sin embargo, actualmente seguimos dependiendo del uso de fungicidas químicos sintéticos convencionales para controlar las enfermedades de poscosecha de fruta fresca en general y de cítricos en particular. Asimismo, existe un incremento de la demanda de los mercados internacionales de frutas y hortalizas frescas de buena calidad e inocuas. Además, el uso de fungicidas convencionales conlleva el problema del desarrollo de resistencia en cepas de P. digitatum y P. italicum. Por otro lado, los resultados en efectividad de la mayoría de los métodos de control no contaminantes no han sido equivalentes a los obtenidos con métodos de control químico convencional. Por todo ello sigue siendo un reto la búsqueda e implementación comercial de estrategias no contaminantes efectivas para el control de las podredumbres verde y azul de los cítricos. Un importante mediador de la respuesta en la patogénesis de estos hongos es el gas etileno, ya que su biosíntesis se incrementa durante la interacción planta-patógeno o después de la aplicación de químicos inductores de resistencia. Además, la producción del etileno puede ser una señal para activar mecanismos de defensa contra patógenos como hongos, bacterias o virus (Ecker y Davis, 1987). Se han realizado estudios orientados a buscar relaciones entre el etileno y la patogenicidad de hongos causantes de enfermedades en poscosecha (Brown, 1973). Sin embargo, discrepancias en los resultados han sido observadas. El etileno es aplicado durante la desverdización de los frutos cítricos, que es una práctica comercial común realizada en muchas partes del mundo (Smilanick et al., 2006), incluyendo España, y se estima que más de 1,2 millones de toneladas de fruta de mandarina de estación temprana se desverdiza anualmente (Martínez-Jávega et al., 2007). Por lo tanto, es de importancia primordial determinar el efecto de esta práctica en la susceptibilidad y desarrollo de las podredumbres verde y azul de los frutos cítricos. Los objetivos serán los siguientes: 1) Evaluar sustancias químicas con antecedentes de potencial de inducción de resistencia para controlar las podredumbres verde y azul de poscosecha en frutos cítricos, 2) Evaluar sustancias conocidas como GRAS (General Regarded as Safe), solas o combinadas con fungicidas para controlar las podredumbres verde y azul en frutos cítricos y, 3) Determinar el efecto del desverdizado comercial con etileno sobre la incidencia y desarrollo de las podredumbres verde y azul en mandarinas y naranjas de estación temprana; así como el efecto del desverdizado comercial sobre los atributos de calidad del fruto. / Moscoso Ramírez, PA. (2013). Aproximaciones a una estrategia integrada para el control no contaminante de las podredumbres verde y azul en poscosecha de cítricos [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/34626 / TESIS

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