Under vintrarna 2006/2007 och 2007/2008 vittnade man i USA om storskaliga förluster avhonungsbin (Apis mellifera). Gemensamma symptom för dessa förluster var att arbetarbinförsvann från kolonierna fastän det fanns rikligt med mat och inga tecken på infektion av någonparasit. Fenomenet fick namnet Colony Collapse Disorder (CCD) eftersom det slutgiltigastadiet var att kolonierna kollapsade. Denna översiktstudie ämnar till att reda ut begreppetCCD och se över vilka potentiella orsaker den rådande forskningen föreslår och vad man harkommit fram till sedan utbrottet 2006. Resultaten indikerar att det antagligen inte är en ensamfaktor bakom CCD utan att flera faktorer samverkar. Det finns ett antal hot mot bina medsymptom som liknar CCD och som antas bidra till försvinnandet. Ett hot är det parasitiskakvalstret Varroa destructor som förutom att det suger binas hemolymfa även agerar vektor åtflera CCD-förknippade patogener som Nosema ceranae och Israeli acute paralysis virus(IAPV). Dessutom sänker V. destructor binas immunförsvar vilket gör att virus som överförsvia kvalstret replikeras snabbare och blir dödligare. Man har även visat att vanligt förekommandebekämpningsmedel kan göra bina mer mottagliga för sjukdomar. Där hittade man ettsignifikant samband med just N. ceranae vilket är i enlighet med teorin om att flera faktorersamverkar. I nuläget bidrar CCD fortfarande till bidöd men är inte lika akut som 2006/2007.Istället är det andra hot såsom biodlares svårighet att behandla invasion av varroakvalster,kalla vintrar och att bisamhällen svälter ihjäl för att de invintras i för små populationer, som ärett större hot än CCD.

Acidentes envolvendo abelhas africanizadas são freqüentemente relatados, particularmente na América do Sul. As picadas de abelhas causam reações localizadas e sistêmicas e os sintomas do envenenamento incluem náuseas, vômitos, hemólise, falência renal e coagulação intravascular disseminada. Durante muito tempo todas as reações tóxicas eram atribuídas à presença de uma fosfolipase A2, mesmo sendo o veneno uma mistura complexa de substâncias. A melitina, o componente mais abundante e tóxico do veneno de abelha, é um peptídeo de 26 aminoácidos com a habilidade de interagir e danificar membranas celulares. A melitina é também capaz de modular muitas proteínas, aumentando a diversidade de atividades biológicas do peptídeo. Até recentemente, acreditava-se que a estrutura tri-dimensional biologicamente ativa do peptídeo, que possui conformação em hélice, era um tetrâmero. Neste trabalho avaliamos a conformação da melitina e seus estados oligoméricos em solução por dinâmica molecular e a interferência da melitina na função plaquetária. Aqui está demonstrado que a melitina possui uma conformação randômica em condições fisiológicas e que sua estrutura tri-dimensional sofre alterações de acordo com as condições ambientais. Ainda, foi demonstrada uma nova atividade biológica do peptídeo melitina. O peptídeo é capaz de induzir a 8 agregação plaquetária de forma dose-dependente e de interagir diretamente com a superfície de plaquetas. A correlação entre a conformação da melitina e suas atividades biológicas é discutida. Os resultados aqui apresentados podem ser valiosos no entendimento do papel da melitina nas coagulopatias induzidas por veneno de abelha. O estudo estrutural mostrado aqui pode ser aplicado para explicar as diferentes atividades do peptídeo. / Accidents involving africanized bees are frequently reported, particularly in South America. Bee stings cause localized and systemic reactions and the symptoms of envenomation include nausea, vomiting, hemolysis, kidney failure and disseminated intravascular coagulation. For a long time, all toxic reactions were ascribe to the presence of a phospholipase A2, despite of being the venom a complex mixture of substances. Melittin, the most abundant and the major toxic component of bee venom, is a 26 amino acid peptide with the ability to interact and disrupt cell membranes. Melittin is also able to modulate many proteins, enhancing the wide range of the peptide biological activities. The biologically active tridimensional structure of the peptide, which has a helical conformation, has been described until now as a tetramer. In this work we evaluated the conformation of melittin and its oligomeric states in solution by molecular dynamics simulations and performed studies of melittin effect on platelet function. Here we demonstrate that melittin has a random conformation under physiological conditions and its tridimensional structure changes under different environmental conditions. Moreover, here we describe a new biological activity of melittin. The peptide is able to induce platelet aggregation in a dose10 dependent manner and can interact directly with the platelet surface. The correlation between melittin conformation and biological activity is discussed. Our results might contribute to elucidate the role of melittin in bee venom induced coagulopathies. The structural data gathered in this work may explain the different activities of the peptide.

Submitted by Reginaldo Soares de Freitas (reginaldo.freitas@ufv.br) on 2017-03-08T16:43:05Z No. of bitstreams: 1 texto completo.pdf: 564049 bytes, checksum: 4e2aaffba113a5a7cfe889fd50aa6203 (MD5) / Made available in DSpace on 2017-03-08T16:43:05Z (GMT). No. of bitstreams: 1 texto completo.pdf: 564049 bytes, checksum: 4e2aaffba113a5a7cfe889fd50aa6203 (MD5) Previous issue date: 1999-08-18 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / O objetivo deste trabalho foi analisar os constituintes químicos do pólen de Stryphnodendron polyphyllum (barbatimão), causador da doença cria-ensacada brasileira (CEB) em Apis mellifera. Para isso, coletaram-se pólen e inflorescência de barbatimão para serem submetidos a extrações sucessivas com hexano e, posteriormente, com etanol. Com os extratos hexânico e etanólico do pólen e da inflorescência obtidos, foram realizados ensaios biológicos, nos quais se verificaram pré-pupas com sintomas da doença nos tratamentos em que as larvas eram alimentadas com dieta de operária mais extrato etanólico. Observou-se a presença de taninos nos extratos etanólicos, tendo sido determinado nestes 7,91 e 21,43% de taninos no pólen e na inflorescência, respectivamente. Com o fracionamento do extrato etanólico do pólen, isolaram-se ainda ácidos graxos e frutose, que foram submetidos a ensaios biológicos. Essas frações não determinaram o aparecimento de sintoma da CEB nas abelhas tratadas. Como várias espécies de barbatimão são conhecidas por possuírem altas concentrações de tanino, realizaram-se ensaios biológicos com concentrações diferentes de ácido tânico para verificar o seu efeito no desenvolvimento das crias de abelhas. Observou-se a presença de sintomas da doença e de alta mortalidade das crias tratadas a partir da terceira alimentação com dieta contendo diferentes concentrações de ácido tânico, tendo sido estimada uma CL50 de 0,012% no referido composto. Diante desses resultados, concluiu-se que o constituinte químico responsável pelos sintomas da cria-ensacada brasileira está presente na fração etanólica do pólen, podendo pertencer ao grupo dos taninos. Os resultados dos ensaios biológicos obtidos com a inflorescência foram semelhantes àqueles conseguidos com o pólen. / The objective of this study was to analyze quimical components of Stryphnnodendron polyphyllum pollen, which cause the Brazilian encapsulated- larvae disease (CEB) in Apis mellifera. Pollen and inflorescence of Stryphnnodendron polyphyllum were collected and gone through successive extraction with hexane and later with ethanol. Biological assays were carried out with the hexane and ethanol extracts obtained from pollen and inflorescence. In those assays it was verified the presence of pre-pupae showing the symptoms of the disease in the treatments where the larvae were fed with the working bees diet supplemented with ethanol extract. It was detected the presence of tannins in ethanol extracts, which was found to be 7,91 and 21,43% of tannins for pollen and inflorescence, respectively. Fructose and fatty acids were isolated from pollen ethanol extract fractionation and were gone through biological assays; in these fractions no symptom of CEB was detected in the treated bees. Since several Stryphnnodendron species are known as containing high tannin concentrations, biological assays using different concentrations of tannic acid were carried out to verify its effect on bee young development. It was observed the presence of CEB symptoms and a high mortality of the young which were treated, from the third feed onwards, with diet containing different concentrations of tannic acid, whose CL50 was estimated at 0,012%. Based on these results, it was concluded that the chemical component which is responsible for the CEB symptoms is present in the ethanol fraction of pollen and it may belong to the tannin group. The results obtained from the inflorescence biological assays were similar to those from pollen.

Les expériences vécues par un individu, vont moduler ses capacités d'apprentissage et induire des modifications structurales dans les régions cérébrales impliquées. Chez l'abeille, de la plasticité dépendante de l'expérience a été observée dans des centres cérébraux impliqués dans l'apprentissage et la mémoire : les corps pédonculés (CPs). Pourtant, les conséquences d'une telle plasticité sur les performances d'apprentissage sont inconnues. L'objectif de ma thèse était d'examiner les relations existantes entre expérience, capacités d'apprentissage et structure des CPs. La division du travail étant basée sur l'âge chez l'abeille, j'ai étudié la plasticité dépendante de l'expérience chez des abeilles jeunes, travaillant dans la ruche, mais aussi chez des abeilles plus âgées qui butinent à l'extérieur. J'ai d'abord observé que des abeilles exposées à un environnement appauvri en stimulations sensorielles et sociales pendant les premiers jours de vie adulte présentent un nombre élevé de boutons synaptiques dans les CPs, et une performance altérée dans un apprentissage dépendant des CPs, l'inversion de consigne. Cela suggère l'existence d'un élagage synaptique dépendant de l'expérience acquise dans la ruche, qui serait bénéfique pour les capacités d'apprentissage. J'ai observé un effet similaire de l'enrichissement environnemental lorsque les abeilles commencent à butiner. Le début du butinage s'est en effet accompagné d'une diminution du nombre de boutons synaptiques dans les CPs et d'une amélioration des performances en inversion de consigne. Une activité prolongée de butinage a eu les effets inverses, en particulier chez des abeilles qui, suite à un stress appliqué à la colonie, butinent avant l'âge normal. J'ai ainsi mis en évidence une relation négative entre le nombre de boutons synaptiques dans les CPs et les performances en inversion de consigne. Par la suite, j'ai utilisé un autre apprentissage dépendant des CPs, le patterning positif, afin de pouvoir conclure sur un déclin généralisé des capacités cognitives dépendantes des CPs chez les butineuses. J'ai montré l'implication du système cholinergique dans le déclin cognitif lié à l'expérience de butinage. Cette thèse réunit les premiers travaux analysant la plasticité dépendante de l'expérience à la fois dans la structure cérébrale, mais aussi dans les capacités cognitives. Elle devrait permettre de comprendre les mécanismes reliant connectivité synaptique et apprentissage, et encourager des études sur l'impact des agents stressants environnementaux sur le déclin cognitif lié au butinage. / Learning capacities, and the structure of the brain centres supporting them, vary greatly between individuals, partly due to different life experiences. In honey bees, experience-dependent plasticity has been reported in brain centres involved in learning and memory: the mushroom bodies (MBs). The consequences of such plasticity on learning performances are still unknown. The aim of my thesis was to examine the relationships between experience, learning capacities and MB organization in honey bees. The age-related division of labour in honey bees gave me the opportunity to study experience-dependent plasticity both in young bees working inside the hive, and in older bees foraging outdoors. I first observed that bees exposed to a sensory-impoverished environment for the first days of adulthood had a higher number of synaptic boutons in the MBs, and a reduced performance in a MB-dependent learning task; reversal learning. This suggests the occurrence of experience-dependent synaptic pruning in the natural environment, which improves learning capacities. I observed similar effects of environmental enrichment when the bees started foraging. Foraging onset was accompanied by a decrease in the number of synaptic boutons in the MBs, as well as by an improvement in reversal learning performance. Prolonged foraging activity, however, had the opposite effects, especially when a stress applied to the colony induced bees to forage earlier. Therefore, I highlighted a negative relationship between the number of synaptic boutons in the MBs and performance in reversal learning. I then confirmed the negative impact of foraging activity on learning capacities using a different MB-dependent task; positive patterning. I revealed the involvement of the cholinergic signalling pathway in this experience-dependent cognitive decline. This thesis presents the first integrated analyses of experience-dependent plasticity in both brain structure and cognitive capacities in honey bees. It helps to understand the mechanisms linking synaptic connectivity to learning performances, and will encourage further studies on the role of environmental stressors in the reported cognitive decline in foragers.

Memoria de Título para optar al título de Ingeniero Agrónomo / Los indicadores de polinización utilizados actualmente son poco eficaces y certeros y ninguno por sí sólo puede indicar a tiempo si existe una buena polinización y adecuado trabajo de las abejas en los árboles frutales. Por lo tanto, este estudio procuró caracterizar el color del polen corbicular de once especies frutales para elaborar una cartilla de colores y evaluar su aplicación en terreno como un indicador de la actividad polinizadora de la abeja melífera (Apis mellifera L.) en huertos frutales. El trabajo de terreno se efectúo en un huerto frutal situado en la Facultad de Ciencias Agronómicas de la Universidad de Chile, en el cual se introdujeron dos colmenas para estudiar el comportamiento y preferencia de las abejas y estimar la atractabilidad que ejercieron sobre ellas las especies del huerto frutal. Cuando las especies frutales florecieron, se sacaron flores y con su polen se realizó una palinoteca de referencia a partir de la cual se describió y fotografió la morfología de los granos. Simultáneamente, el polen cosechado de las trampas colocadas en las colmenas, se separó por colores y se observó al microscopio óptico para buscar e identificar las once especies frutales consideradas en este estudio. Se observó que, dentro del huerto frutal, destacaron por el pecoreo de polen los cultivares de peral Packham‟s Triumph, damasco Dina y cerezo Brooks y, por el pecoreo de néctar, todos los cultivares de mandarino y naranjo, junto con el ciruelo europeo D‟Agen y cerezo Brooks. Dentro del polen corbicular se encontró sólo tres especies frutales correspondientes a Prunus armeniaca L., Pyrus communis L. y Citrus limon (L.) Osbeck, a las que se les midió el color con colorímetro y se les asignó también un color de la Cartilla Pantone®. El polen corbicular de estas especies tiende al color amarillo (h*= 90°) con leves diferencias en su cromaticidad (C*) y luminosidad (L*). Se concluye que es posible elaborar una cartilla de colores del polen corbicular de distintas especies de árboles frutales y aplicarla en terreno considerando que para su uso, se requiere complementar la observación en terreno de las abejas pecoreando el polen en estudio, con el color y el conocimiento de las fechas de floración de toda la flora circundante, sobre todo la atractiva a las abejas, en un radio no menor de 1,2 km y ampliable hasta 3 km, del lugar donde se vaya a utilizar. / Currently used pollination indicators have limited effectiveness and accuracy and none by themselves can opportunely indicate the occurrence of good pollination and suitable foraging of honey bees in fruit trees. Therefore, the aim of this research was to characterize the color of corbicular pollen loads of 11 species of fruit trees to develop a color chart and assess its field application as an indicator of the pollinating activity of honey bees (Apis mellifera L.) in fruit orchards. The field work was carried out in a fruit tree orchard located at the Faculty of Agricultural Sciences of the University of Chile, where two hives were introduced to study the behavior and preference of honey bees and estimate the attractability exerted on them by the orchard species. When orchard species bloomed, flowers were taken to collect pollen grains for making a reference palinoteque based on which pollen grain morphology was described and photographed. Simultaneously, pollen harvested from traps placed in the hives was classified by color and observed by optical microscopy to look for and identify the 11 fruit species considered in this research. It was observed that, within the fruit orchard, the cultivars that stood out for pollen foraging by bees were the „Packham‟s Triumph‟ pear, the „Dina‟ apricot, and the „Brooks‟ cherry, while those preferred for nectar foraging were all the mandarin and orange cultivars together with the European „D‟Agen‟ plum and „Brooks‟ cherry. Just three fruit species, Prunus armeniaca L., Pyrus communis L. and Citrus limon (L.) Osbeck, were found in the corbicular pollen, whose color was measured with a colorimeter and associated to the Pantone® Color Chart. The corbicular pollen of these species tends to the yellow color (h*= 90°) with slight differences in its chromaticity (C*) and lightness (L*). It is concluded that it is possible to design a color chart of corbicular pollen loads from different fruit tree species for field application, considering that for its use complement the observation on field of bees foraging the studied pollen is required together with the pollen color, and knowledge of the surrounding flora and its blooming dates, especially the flora attractive to bees, in a radius not less than 1,2 km and expandable to 3 km from the selected place.

Acidentes envolvendo abelhas africanizadas são freqüentemente relatados, particularmente na América do Sul. As picadas de abelhas causam reações localizadas e sistêmicas e os sintomas do envenenamento incluem náuseas, vômitos, hemólise, falência renal e coagulação intravascular disseminada. Durante muito tempo todas as reações tóxicas eram atribuídas à presença de uma fosfolipase A2, mesmo sendo o veneno uma mistura complexa de substâncias. A melitina, o componente mais abundante e tóxico do veneno de abelha, é um peptídeo de 26 aminoácidos com a habilidade de interagir e danificar membranas celulares. A melitina é também capaz de modular muitas proteínas, aumentando a diversidade de atividades biológicas do peptídeo. Até recentemente, acreditava-se que a estrutura tri-dimensional biologicamente ativa do peptídeo, que possui conformação em hélice, era um tetrâmero. Neste trabalho avaliamos a conformação da melitina e seus estados oligoméricos em solução por dinâmica molecular e a interferência da melitina na função plaquetária. Aqui está demonstrado que a melitina possui uma conformação randômica em condições fisiológicas e que sua estrutura tri-dimensional sofre alterações de acordo com as condições ambientais. Ainda, foi demonstrada uma nova atividade biológica do peptídeo melitina. O peptídeo é capaz de induzir a 8 agregação plaquetária de forma dose-dependente e de interagir diretamente com a superfície de plaquetas. A correlação entre a conformação da melitina e suas atividades biológicas é discutida. Os resultados aqui apresentados podem ser valiosos no entendimento do papel da melitina nas coagulopatias induzidas por veneno de abelha. O estudo estrutural mostrado aqui pode ser aplicado para explicar as diferentes atividades do peptídeo. / Accidents involving africanized bees are frequently reported, particularly in South America. Bee stings cause localized and systemic reactions and the symptoms of envenomation include nausea, vomiting, hemolysis, kidney failure and disseminated intravascular coagulation. For a long time, all toxic reactions were ascribe to the presence of a phospholipase A2, despite of being the venom a complex mixture of substances. Melittin, the most abundant and the major toxic component of bee venom, is a 26 amino acid peptide with the ability to interact and disrupt cell membranes. Melittin is also able to modulate many proteins, enhancing the wide range of the peptide biological activities. The biologically active tridimensional structure of the peptide, which has a helical conformation, has been described until now as a tetramer. In this work we evaluated the conformation of melittin and its oligomeric states in solution by molecular dynamics simulations and performed studies of melittin effect on platelet function. Here we demonstrate that melittin has a random conformation under physiological conditions and its tridimensional structure changes under different environmental conditions. Moreover, here we describe a new biological activity of melittin. The peptide is able to induce platelet aggregation in a dose10 dependent manner and can interact directly with the platelet surface. The correlation between melittin conformation and biological activity is discussed. Our results might contribute to elucidate the role of melittin in bee venom induced coagulopathies. The structural data gathered in this work may explain the different activities of the peptide.

Orientador: José Chaud Netto / Banca: Valter Vieira Alves Júnior / Banca: Júlio Valentim Betioli / Resumo: No presente estudo avaliou-se o efeito do macerado floral e de extratos folhares de L. camara em operárias de Apis mellifera. Abelhas africanizadas recém-emergidas foram coletadas e marcadas, sendo posteriormente introduzidas em um núcleo contendo 3 favos cobertos por abelhas adultas e apresentando boa quantidade de mel e pólen. Dois desses favos possuíam um grande número de operárias em diferentes fases de desenvolvimento. Sete dias após a marcação as abelhas foram transferidas para caixas de laboratório mantidas em estufa bacteriológica a 34° C l 1° C e umidade relativa de 60 l 5%. Nas primeiras séries de bioensaios, em que foi testado o macerado floral, os grupos experimentais receberam pasta-cândi acrescida do macerado em concentrações variadas (30%, 10%, 7,5%, 5% e 2,5%), enquanto as abelhas dos grupos-controle receberam somente cândi. Os resultados das análises de sobrevivência indicaram que as abelhas alimentadas com cândi acrescido do macerado floral a 30%, 10% e 7.5% apresentaram uma menor longevidade (P < 0,0001), em relação às operárias dos grupos-controle. Estes resultados sugerem a existência de alguma substância tóxica no macerado floral de L. camara capaz de diminuir a longevidade das operárias. Na segunda série de bioensaios, as operárias receberam, por meio de aplicação tópica na região do pronoto, 2æL do extrato metanólico das folhas de L. camara nas concentrações de 0,0888 mg/abelha, 0,0444 mg/abelha e 0,0222 mg/abelha, enquanto que as abelhas do grupo controle receberam somente metanol. As análises de sobrevivência revelaram que os extratos de L. camara não interferiram na longevidade das operárias / Abstract: In this study the effect of the floral crushed and foliage extracts of L. camara in Apis mellifera workers was evaluated. Newly-emerged Africanized honeybee workers were collected and marked, being later introduced in a beehive containing three frames covered with bees and presenting good amount of honey, pollen and a great number of workers in different phases of development. Seven days after, the bees were transferred to laboratory boxes maintained in a bacteriological stove at 34° C l 1° C and relative humidity of 60 l 5%. In the first series of bioassays the honeybee workers of the experimental groups received candy plus floral crushed of L. camara in variable concentrations (30%, 10%, 7.5%, 5% and 2.5%), while the bees of the control groups were fed only with candy. The survival analyses indicated that bees fed with candy plus the floral crushed at 30%, 10% and 7.5% have a shorter life time (P <0,0001), in relation to the workers of the control groups. These results suggest the presence of some toxic substance in the floral crushed of L. camara, able to diminish the life time of adult workers. In the second series of bioassays the honeybee workers received, by topical application on the pronotum, 2æL of methanolic extracts of L. camara leaves in the concentrations of 0,0888 mg/bee, 0,0444 mg/bee and 0,0222 mg/bee, while the workers of the control groups received only methanol. The survival analyses revealed that the extracts of L. camara did not affect the worker's longevity / Mestre

Made available in DSpace on 2014-06-11T19:30:14Z (GMT). No. of bitstreams: 0 Previous issue date: 2005-10-27Bitstream added on 2014-06-13T19:18:42Z : No. of bitstreams: 1 pereira_am_me_rcla.pdf: 453810 bytes, checksum: 9d141c92ea13cc88e6e95ae064e3bba4 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / No presente estudo avaliou-se o efeito do macerado floral e de extratos folhares de L. camara em operárias de Apis mellifera. Abelhas africanizadas recém-emergidas foram coletadas e marcadas, sendo posteriormente introduzidas em um núcleo contendo 3 favos cobertos por abelhas adultas e apresentando boa quantidade de mel e pólen. Dois desses favos possuíam um grande número de operárias em diferentes fases de desenvolvimento. Sete dias após a marcação as abelhas foram transferidas para caixas de laboratório mantidas em estufa bacteriológica a 34° C l 1° C e umidade relativa de 60 l 5%. Nas primeiras séries de bioensaios, em que foi testado o macerado floral, os grupos experimentais receberam pasta-cândi acrescida do macerado em concentrações variadas (30%, 10%, 7,5%, 5% e 2,5%), enquanto as abelhas dos grupos-controle receberam somente cândi. Os resultados das análises de sobrevivência indicaram que as abelhas alimentadas com cândi acrescido do macerado floral a 30%, 10% e 7.5% apresentaram uma menor longevidade (P < 0,0001), em relação às operárias dos grupos-controle. Estes resultados sugerem a existência de alguma substância tóxica no macerado floral de L. camara capaz de diminuir a longevidade das operárias. Na segunda série de bioensaios, as operárias receberam, por meio de aplicação tópica na região do pronoto, 2æL do extrato metanólico das folhas de L. camara nas concentrações de 0,0888 mg/abelha, 0,0444 mg/abelha e 0,0222 mg/abelha, enquanto que as abelhas do grupo controle receberam somente metanol. As análises de sobrevivência revelaram que os extratos de L. camara não interferiram na longevidade das operárias. / In this study the effect of the floral crushed and foliage extracts of L. camara in Apis mellifera workers was evaluated. Newly-emerged Africanized honeybee workers were collected and marked, being later introduced in a beehive containing three frames covered with bees and presenting good amount of honey, pollen and a great number of workers in different phases of development. Seven days after, the bees were transferred to laboratory boxes maintained in a bacteriological stove at 34° C l 1° C and relative humidity of 60 l 5%. In the first series of bioassays the honeybee workers of the experimental groups received candy plus floral crushed of L. camara in variable concentrations (30%, 10%, 7.5%, 5% and 2.5%), while the bees of the control groups were fed only with candy. The survival analyses indicated that bees fed with candy plus the floral crushed at 30%, 10% and 7.5% have a shorter life time (P <0,0001), in relation to the workers of the control groups. These results suggest the presence of some toxic substance in the floral crushed of L. camara, able to diminish the life time of adult workers. In the second series of bioassays the honeybee workers received, by topical application on the pronotum, 2æL of methanolic extracts of L. camara leaves in the concentrations of 0,0888 mg/bee, 0,0444 mg/bee and 0,0222 mg/bee, while the workers of the control groups received only methanol. The survival analyses revealed that the extracts of L. camara did not affect the worker's longevity.

Submitted by Marco Antônio de Ramos Chagas (mchagas@ufv.br) on 2018-05-24T13:20:21Z No. of bitstreams: 1 texto completo.pdf: 3999297 bytes, checksum: 3df888fff3753cef075cf9629a59a85d (MD5) / Made available in DSpace on 2018-05-24T13:20:21Z (GMT). No. of bitstreams: 1 texto completo.pdf: 3999297 bytes, checksum: 3df888fff3753cef075cf9629a59a85d (MD5) Previous issue date: 2017-07-14 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / A abelha Apis mellifera tem importância ecológica e econômica, no entanto, sofre um declínio populacional, talvez devido à exposição a compostos tóxicos, que são excretados pelos túbulos de Malpigui. Durante a metamorfose de A. mellifera, os túbulos de Malpigui degeneram e são formados de novo. O objetivo deste trabalho foi verificar os eventos celulares na renovação dos túbulos Malpighi, acompanhando na metamorfose, quais as etapas da remodelação celular, determinando os tipos celulares e seus papéis na atividade excretora e inicio do controle homeostático em A. mellifera. As análises ultraestruturais e de imunofluorescência mostraram que as células dos túbulos de Malpighi de larvas degeneraram por apoptose e autofagia (larva L5S e pré-pupa) e novos túbulos de Malpigui são formados por proliferação celular. (larva L5S e pupa de olhos castanhos). A ultraestrutura das células dos túbulos de Malpigui sugere que uma remodelação celular ocorra a partir de pupa de olhos marrons, indicando o inicio de uma atividade de excreção nos túbulos de Malpigui pupais. Em abelhas adultas (recém-emergida e forrageira), dois tipos celulares ocorrem nos túbulos de Malpigui, um com características ultraestruturais de produção da urina primária e outro tipo de célula com características que sugerem um papel na reabsorção da urina primária. Este estudo sugere que, durante a metamorfose, os túbulos de Malpigui não são funcionais até pupa de olhos castanhos, indicando que A. mellifera pode ser vulnerável a compostos tóxicos nas primeiras nas fases pupais. Além disso, a ultraestrutura celular sugere que os túbulos Malpigui podem ser funcionais a partir de pupa de olhos marrons e adquirem maior complexidade na abelha operária forrageira. Nos insetos, o intestino posterior é um órgão homeostático, sendo este dividido em piloro, íleo e reto, que reabsorvem água, íons e pequenas moléculas produzidas na filtragem da hemolinfa e nas fezes. Esse estudo reporta as mudanças morfológicas e os eventos celulares que ocorrem no intestino posterior durante a metamorfose da abelha A. mellifera. No intestino posterior, a imunolocalização de autofagossomos e a ultraestrutura as células epiteliais e do revestimento cuticular sugerem que em pré-pupa tem início a degradação cuticular, que em pupas de olhos brancos e rosas é reabsorvida e reciclada por autofagossomos, sendo a deposição da nova cutícula em pupa de olhos castanhos. Em larva L5S e pré-pupa, o intestino posterior apresenta proliferação celular em suas extremidades anterior e posterior. Na pupa, as regiões do piloro, íleo e reto estão evidentes e com proliferações celulares que cessam a partir de pupa de olhos marrons. Apoptose ocorre de larva L5S até pupa de olhos rosas. Em pupas de olhos castanhos e marrons, o epitélio do íleo muda de pseudoestratificado para simples somente após a produção da lâmina basal e o epitélio retal é achatado. Nas células do íleo de pupa de olhos pretos ocorrem grandes vacúolos e espaços subcuticulares, enquanto que na operária adulta forrageira, ocorrem invaginações apicais longas e muitas mitocôndrias, sugerindo uma atividade no transporte de compostos. Os resultados mostram que a morfogênese do intestino posterior é dinâmica, com remodelações teciduais e eventos celulares para a formação de diferentes regiões do órgão, reconstrução de uma nova cutícula e remodelação dos músculos viscerais. / The honeybee Apis mellifera has ecological and economic importance, however, experience a population decline, perhaps due to exposure to toxic compounds, which are excreted by Malpighian tubules. During metamorphosis of A. mellifera, the Malpighian tubules degenerate and are formed de novo. The objective of this work was to verify the cellular events of the Malpighian tubules renewal and accompany in the metamorphosis, which are the gradual steps of cell remodeling, determining different cell types and their roles in the excretory activity and onset of homeostatic control in A. mellifera. Immunofluorescence and ultrastructural analyses showed that the cells of the larval Malpighian tubules degenerate by apoptosis and autophagy (larvae instar L5S and prepupae) and the new Malpighian tubules are formed by cell proliferation (L5S larvae until light-brown eyed pupae). The ultrastructure of the cells in the Malpighian tubules suggest that cellular remodeling only occurs from dark-brown eyed pupae, indicating the onset of excretion activity in pupal Malpighian tubules. In adult bees (newly emerged and forager), two cell types occur in the Malpighian tubules, one with ultrastructural features of primary urine production and another cell type with characteristics that suggest a role in primary urine reabsorpotion. This study suggest that during the metamorphosis, Malpighian tubules are non-functional until the light-brown eyed pupae, indicating that A. mellifera may be more vulnerable to toxic compounds at early pupal stages. In addition, cell ultrastructure suggests that the Malpighian tubules may be functional from dark-brown eyed pupae and acquire greater complexity in the forager worker bee. In insects, the hindgut is a homeostatic region of the digestive tract, divided into pylorus, ileum, and rectum, that reabsorbs water, ions, and small molecules produced during hemolymph filtration. The hindgut anatomy in bee larvae is different from that of adult workers. This study reports the morphological changes and cellular events that occur in the hindgut during the metamorphosis of the honeybee Apis mellifera. We describe the occurrence of autophagosomes and the ultrastructure of the epithelial cells and cuticle, suggesting that cuticular degradation begins in prepupae, with the cuticle being reabsorbed and recycled by autophagosomes in white- and pink- eyed pupae, followed by the deposition of new cuticle in light-brown-eyed pupae. In L5S larvae and prepupae, the hindgut undergoes cell proliferation in the anterior and posterior ends. In the pupae, the pylorus, ileum, and rectum regions are differentiated, and cell proliferation ceases in dark-brown-eyed pupae. Apoptosis occurs in the hindgut from the L5S larval to the pink-eyed pupal stage. In light-brown- and dark-brown-eyed pupae, the ileum epithelium changes from pseudostratified to simple only after the production of the basal lamina, whereas the rectal epithelium is always flattened. In black-eyed pupae, ileum epithelial cells have large vacuoles and subcuticular spaces, while in adult forager workers these cells have long invaginations in the cell apex and many mitochondria, indicating a role in the transport of compounds. Our findings show that hindgut morphogenesis is a dynamic process, with tissue remodeling and cellular events taking place for the formation of different regions of the organ, the reconstruction of a new cuticle, and the remodeling of visceral muscles.

The discovery of the honeybee-specific ectoparasitic mite Varroa destructor in South Africa in October 1997 raised the spectre of massive honeybee colony losses as has occurred in most parts of the world where the varroa mite has been found. This was particularly concerning in Africa because of the importance of honeybees in the pollination of indigenous and commercial crops, and because of the numbers of small-scale beekeepers in Africa. The mite has now spread throughout South Africa and is found in almost all honeybee populations, both commercial and wild, and is also now present in most neighbouring countries. Varroa has not left a trail of destruction in South Africa as had been expected and no large scale collapse of the honeybee population occurred, despite the majority of beekeepers deciding not to protect their hives with chemical varroacides. Some colony losses did occur at the front of the varroa spread, and all colonies were found to be deleteriously affected by the mite which developed populations of 50 000 and more in some colonies. Infected colonies were also not as efficient as pollinators as uninfected colonies. Colonies exhibited all the same varroa effects witnessed in other parts of the world, with the exception that the majority of colonies did not die as a result of the infestation. The relative tolerance of African bees to the varroa mite has been confirmed by the long-term monitoring of both wild honeybee populations and commercial stock, and by population dynamic studies of the mites. In both wild and managed honeybee populations varroa appears to have been reduced to the status of an incidental pest. The development of mite tolerance took 3-5 years in the Cape honeybee (Apis mellifera capensis) and 6-7 years in the Savanna honeybee (Apis mellifera scutellata). The rapid development of mite tolerance in the Cape bee is thought to be due to the well developed removal of varroa-infested brood and the short post-capping period of worker brood. Together these resulted in a very rapid increase in infertile mites in the colony, the collapse of the mite population, and varroa tolerance. Tolerance does not develop as rapidly in Savanna honeybees as the post-capping period in these bees is similar to that of European bees and does not result in as many infertile mites. Nonetheless, varroa tolerance in Savanna bees develops more rapidly than would be the case in European bees because of more effective hygienic removal of varroa-infested brood. In both Cape and Savanna bees, the absence of varroacide applications and a “live-and-let-die” approach to the wild and commercial honeybee populations was crucial to the developed of population-wide varroa tolerance, in contrast to the selective breeding and pesticide treadmill practised in most parts of the world in an effort to get rid of the varroa mite. Varroa destructor is concluded not to be a serious threat to honeybees and beekeeping in Africa, and efforts should be made to prevent the use of pesticides and techniques that could hinder the development of natural mite tolerance in Africa. / Dissertation (MSc (Entomology))--University of Pretoria, 2007. / Zoology and Entomology / unrestricted