The sex comb an array of specialized bristles on the foreleg, is a highly variable male trait of Drosophila that provides an ideal system for integrative studies of morphological evolution. Here, studies of the genetic and developmental architecture of sex comb bristle number variation in Drosophila melanogaster are described. Analysis of the response to twenty-four generations of divergent artificial selection indicated high genetic variance underlying this trait, and demonstrated a weak relationship with other, developmentally related non-sex bristle systems. I also present evidence showing bristle number is associated with mating success. Manipulation of diet in full-sib families confirmed that this trait is condition dependent, and that there is a genetic basis for condition dependence. Further partitioning of variance components using a half-sib mating design revealed a strong maternal, dominance and/or X chromosome effect on sex comb bristle number variation. Finally, sex comb bristle number was not correlated with comb orientation in wild type, High and Low artificial selection lines, or the mutant strain bric a brac PR72. Analysis of patterns of variation in comb orientation over ontogeny in these lines showed that this aspect of the sex comb phenotype is highly canalized. This body of work provides important insight into D. melanogaster sex comb evolvability, and represents a timely approach to bridging the gap between population genetics and development in studies of phenotypic evolution. / Thesis / Doctor of Philosophy (PhD)

A assimetria de cinco estruturas corporais da mosca-das-frutas Ceratitis capitata foi analisada para uma avaliação se poderiam ser utilizadas como bioindicadores. As análises foram feitas em amostras de uma população natural e de uma população de laboratório. Adicionalmente, em amostras obtidas da população de laboratório, os índices de assimetria foram avaliados após a submissão das diferentes amostras à diferentes temperaturas. No estágio de pupa, as amostras foram tratadas nas temperaturas de 17, 20, 25 e 30oC. As estruturas analisadas, em machos e fêmeas foram as cerdas frontais (FO), orbitais (OB), pós-oculares (PO), o comprimento e largura das asas. Nos machos, além dessas estruturas, foi incluída a análise do comprimento de uma das cerdas orbitais, a supra-fronto-orbital (SFO), que apresenta dimorfismo sexual. A variação numérica das cerdas FO e OB foi muito baixa em todas as amostras, não permitindo uma análise da assimetria. A assimetria das demais características, tanto merísticas como métricas, mostrou ser compatível com o modelo da assimetria flutuante (AF). O grau de assimetria de cada estrutura não diferiu entre machos e fêmeas, mas foi significativamente mais alto na amostra da população de laboratório do que na amostra da população natural. No entanto, a assimetria holística (somatória da AF das diferentes estruturas) não mostrou diferenças entre as duas amostras. Nas amostras submetidas a diferentes temperaturas foram observadas alterações significativas no grau de assimetria das estruturas, mas nenhuma alteração no tipo de assimetria que continuou sendo caracterizada como flutuante. Essas análises mostraram não haver diferenças entre os sexos, nem interações entre sexo e temperatura, mas apenas diferenças significativas entre as temperaturas. A assimetria flutuante das cerdas pós-oculares aumenta com o elevação da temperatura, a AF do comprimento das asas e da cerda SFO (nos machos) não mostra correlação com as temperaturas e os resultados indicam que a AF da largura das asas é mais elevada nas temperaturas extremas que nas intermediárias. A comparação da assimetria holística entre as amostras das diferentes temperaturas mostrou que as diferenças não foram significativas. Os resultados indicam que a assimetria das 52 cerdas pós-oculares e das medidas do largura das asas apresentam potencial para evidenciar eventuais estresses durante o desenvolvimento desses insetos. Indicam, também, que a utilização de uma assimetria holísitca pode mascarar possíveis diferenças da assimetria flutuante de estruturas individuais. / Asymmetry of five traits of the fruit fly Ceratitis capitata, an introduced insect pest in Brazil, was analysed in order to evaluate if they present potencial to be used as bioindicators of the \"quality\" of these insects. Samples from a natural population and from a laboratory colony were studied. Moreover, asymmetry was measured in samples from the laboratory colony maintained during the pupal stage, in the temperatures of 17, 20, 25 and 30oC. The analysed traits of males and females, were the frontal, the orbital and the postocular bristles, measurement of the length and cross diameter of the wings and the length of the supra-frontoorbital bristles in the males that show a pronounced sexual dimorphism. Since the numerical variation of the frontal and orbital bristles was very low in all samples it was not possible to analyse the variation in terms of asymmetry. For all other traits, meristic or metric, asymmetry was characterized as following the fluctuating asymmetry (AF) model. AF of the different traits does not differ between sexes, but was significantly higher in the laboratory sample than in the sample from the natural population. No significant differences, however, were found in the holistic asymmetry (sum of AF of different traits) between the two samples. In relation to the experiments conducted in different temperatures, no variations in AF levels were observed between sexes, nor interactions between sex and temperatures. However, significant differences were observed among the samples submitted to different temperatures. AF of the postocular bristles increases proportionaly to the increment of the temperature, while AF of wings and supra-fronto-orbital bristles (in males) lengths showed no correlations with the temperatures, and AF of the cross diameter of wings seems to be higher at the extreme temperatures than at the intermediate ones. When a holistic AF was applied, no significant differences among the temperature samples were observed. The results indicate that asymmetry of the postocular bristles and the length of the wings are parameters showing potencial use as indicators of stresses during development of these insects. They also indicate that a holistic asymmetry may mask variations in the asymmetry of individual traits.

<p>Mutations in myosin VIIa (MyoVIIa), an unconventional myosin, have been shown to cause Usher Syndrome Type 1B in humans. Usher Syndrome Type 1B is characterized by congenital sensorineural deafness, vestibular dysfunction and pre-pubertal onset of <italic>retinitis pigmentosa</italic>. Mouse model studies show that sensorineural deafness and vestibular dysfunction in MyoVIIa mutants is caused by disruption in the structure of microvilli-like projections (stereocilia) of hair cells in the cochlea and vestibular organ. MyoVIIa has also been shown to affect adaptation of mechanoelectrical transduction channels in stereocilia. </p><p>In <italic>Drosophila melanogaster</italic> mutations in MyoVIIa encoded by <italic>crinkled (ck)</italic> cause defects in hair and bristle morphogenesis and deafness. Here we study the formation of bristles and hairs in <italic>Drosophila melanogaster</italic> to investigate the molecular basis of ck/MyoVIIa function and its regulation. We use live time-lapse confocal microscopy and genetic manipulations to investigate the requirement of ck/MyoVIIa function in various steps of morphogenesis of hairs and bristles. Here we show that null or near null mutations in ck/MyoVIIa lead to the formation of 8-10 short and thin hairs (split hairs) per epithelial cell that are likely the result of the failure of association of hair-actin bundles that in wild-type cells come together to form a single hair.</p><p>The myosin super family of motor proteins is divided into 17 classes by virtue of differences in the sequence of their motor domain, which presumably affect their physiological functions. In addition, substantial variety in the overall structure of their tail plays an important role in the differential regulation of myosin function. In this study we show that ck/MyoVIIa, that has two MyTH4 FERM domains in its tail separated by an SH3 domain, requires both MyTH4 FERM repeats for efficient association of hair-actin bundles to form hairs. We also show that the "multiple hair" phenotype of over-expression of ck/MyoVIIa requires both MyTH4 FERM domain function but not the tail-SH3 domain. We further demonstrate that the tail-SH3 domain of ck/MyoVIIa plays a role in keeping actin bundles, which run parallel to the length of the growing bristle, separate from each other. Our data also suggests that the tail-SH3 domain plays a role in the association of the actin filament bundles with the membrane and regulates F-actin levels in bristles.</p><p>We further demonstrate that over-expression of <italic>Quail</italic> (villin) can rescue the hair elongation defects seen in ck/MyoVIIa null or near null mutants but does not rescue the split hair defects. We show that over-expression of <italic>Alpha-actinin-GFP</italic>, another actin bundling protein, phenocopies the multiple hair phenotype of ck/MyoVIIa over-expression. Over-expression of <italic>Alpha-actinin-GFP</italic> in a ck/MyoVIIa null or near null background shows that <italic>Alpha-actinin-GFP</italic> cannot rescue the split or short hair phenotype of ck/MyoVIIa loss-of-function. However, cells over-expressing <italic>Alpha-actinin-GFP</italic> in a ck/MyoVIIa null or near null background have more than the normal 8-10 split hairs, suggesting that <italic>Alpha-actinin-GFP</italic> over-expression causes the formation of more than the normal complement of hair-actin bundles per cell, resulting in a multiple hair phenotype. We show that <italic>Twinfilin</italic>, an actin monomer sequestering protein implicated in negatively regulating F-actin bundle elongation in stereocilia in a MyoVIIa-dependent manner, is required for F-actin bundle stability. </p><p>In addition, we use yeast two-hybrid strategies to identify <italic>Slam</italic> as a protein that directly binds to ck/MyoVIIa. We show that <italic>Slam</italic>, a novel membrane-associated protein, likely functions to regulate ck/MyoVIIa function during hair and bristle morphogenesis. We show that over-expression of <italic>Slam</italic> and loss-of-function mutations in <italic>Slam</italic> phenocopy ck/MyoVIIa loss-of-function split and short hair phenotype. We also show that disruption of <italic>Slam</italic> and <italic>RhoGEF2</italic> association causes split hair defects similar to ck/MyoVIIa loss-of-function phenotype suggesting that Slam probably regulates ck/MyoVIIa function via <italic>RhoGEF2</italic>.</p><p>Together our results show that ck/MyoVIIa plays an important role in regulating the actin cytoskeleton that underlies actin-based cellular protrusions like hairs and bristles.</p> / Dissertation

Brush seals are contact seals which are efficient and reliable and can beused in any rotatory machinery. A theoretical model of a brush seal wassuggested and used for a simulation study. Comparison between the resultsof the experiment and simulation is used to verify the accuracy of model.Following the basic simulation steps, more simulation will be done to geta further analysis. The further analysis will be studied in bristles’ bucklingcharacteristics, deformation and stress. The buckling, stress anddeformation is related to the brush seal’s performance. This work givesthe different geometry of bristle’s effect to its buckling characteristics andthe study of stress and deformation caused by fluid flow across bristlesduring operation.

A assimetria de cinco estruturas corporais da mosca-das-frutas Ceratitis capitata foi analisada para uma avaliação se poderiam ser utilizadas como bioindicadores. As análises foram feitas em amostras de uma população natural e de uma população de laboratório. Adicionalmente, em amostras obtidas da população de laboratório, os índices de assimetria foram avaliados após a submissão das diferentes amostras à diferentes temperaturas. No estágio de pupa, as amostras foram tratadas nas temperaturas de 17, 20, 25 e 30oC. As estruturas analisadas, em machos e fêmeas foram as cerdas frontais (FO), orbitais (OB), pós-oculares (PO), o comprimento e largura das asas. Nos machos, além dessas estruturas, foi incluída a análise do comprimento de uma das cerdas orbitais, a supra-fronto-orbital (SFO), que apresenta dimorfismo sexual. A variação numérica das cerdas FO e OB foi muito baixa em todas as amostras, não permitindo uma análise da assimetria. A assimetria das demais características, tanto merísticas como métricas, mostrou ser compatível com o modelo da assimetria flutuante (AF). O grau de assimetria de cada estrutura não diferiu entre machos e fêmeas, mas foi significativamente mais alto na amostra da população de laboratório do que na amostra da população natural. No entanto, a assimetria holística (somatória da AF das diferentes estruturas) não mostrou diferenças entre as duas amostras. Nas amostras submetidas a diferentes temperaturas foram observadas alterações significativas no grau de assimetria das estruturas, mas nenhuma alteração no tipo de assimetria que continuou sendo caracterizada como flutuante. Essas análises mostraram não haver diferenças entre os sexos, nem interações entre sexo e temperatura, mas apenas diferenças significativas entre as temperaturas. A assimetria flutuante das cerdas pós-oculares aumenta com o elevação da temperatura, a AF do comprimento das asas e da cerda SFO (nos machos) não mostra correlação com as temperaturas e os resultados indicam que a AF da largura das asas é mais elevada nas temperaturas extremas que nas intermediárias. A comparação da assimetria holística entre as amostras das diferentes temperaturas mostrou que as diferenças não foram significativas. Os resultados indicam que a assimetria das 52 cerdas pós-oculares e das medidas do largura das asas apresentam potencial para evidenciar eventuais estresses durante o desenvolvimento desses insetos. Indicam, também, que a utilização de uma assimetria holísitca pode mascarar possíveis diferenças da assimetria flutuante de estruturas individuais. / Asymmetry of five traits of the fruit fly Ceratitis capitata, an introduced insect pest in Brazil, was analysed in order to evaluate if they present potencial to be used as bioindicators of the \"quality\" of these insects. Samples from a natural population and from a laboratory colony were studied. Moreover, asymmetry was measured in samples from the laboratory colony maintained during the pupal stage, in the temperatures of 17, 20, 25 and 30oC. The analysed traits of males and females, were the frontal, the orbital and the postocular bristles, measurement of the length and cross diameter of the wings and the length of the supra-frontoorbital bristles in the males that show a pronounced sexual dimorphism. Since the numerical variation of the frontal and orbital bristles was very low in all samples it was not possible to analyse the variation in terms of asymmetry. For all other traits, meristic or metric, asymmetry was characterized as following the fluctuating asymmetry (AF) model. AF of the different traits does not differ between sexes, but was significantly higher in the laboratory sample than in the sample from the natural population. No significant differences, however, were found in the holistic asymmetry (sum of AF of different traits) between the two samples. In relation to the experiments conducted in different temperatures, no variations in AF levels were observed between sexes, nor interactions between sex and temperatures. However, significant differences were observed among the samples submitted to different temperatures. AF of the postocular bristles increases proportionaly to the increment of the temperature, while AF of wings and supra-fronto-orbital bristles (in males) lengths showed no correlations with the temperatures, and AF of the cross diameter of wings seems to be higher at the extreme temperatures than at the intermediate ones. When a holistic AF was applied, no significant differences among the temperature samples were observed. The results indicate that asymmetry of the postocular bristles and the length of the wings are parameters showing potencial use as indicators of stresses during development of these insects. They also indicate that a holistic asymmetry may mask variations in the asymmetry of individual traits.

One of the best-known structures in Drosophila is the sex comb, an arrangement of modified bristles on the tarsal forelegs of males. This complex, sexually-dimorphic trait shows striking variation among closely related species, although most other aspects of the tarsal bristle pattern have been conserved. I studied the development of the sex comb in the model organism Drosophila melanogaster and six related species. I confirmed that the D. melanogaster sex comb, although longitudinal in the adult, originates in a transverse orientation and rotates during development, and showed that this process occurs through male-specific convergent extension. However, in the species that I examined that have longitudinally-oriented sex combs that extend the full length of the tarsus, including D. ficusphila and two species of the montium subgroup, the sex comb does not rotate, and instead forms from two longitudinal rows that converge during development. Another species of the montium subgroup, D. nikananu, has a sex comb that is convergently similar to D. melanogaster, but forms in a manner typical of its subgroup, showing that very similar combs can be formed through different processes. In all species, there is a strong correlation between the position of the sex comb and the transverse bristle row on the foreleg tarsus just proximal to it. To test whether it is possible to violate this apparent constraint on development, I perturbed the expression of the leg patterning gene dachshund to generate ectopic sex combs in D. melanogaster. I found that while most patterns showed the same correlation, a few circumvent the constraint. I also demonstrated that the ectopic combs were formed non-autonomously and that overexpression of dachshund can transform certain aspects of the sex comb phenotype to resemble the transverse bristles to which they are homologous.

One of the best-known structures in Drosophila is the sex comb, an arrangement of modified bristles on the tarsal forelegs of males. This complex, sexually-dimorphic trait shows striking variation among closely related species, although most other aspects of the tarsal bristle pattern have been conserved. I studied the development of the sex comb in the model organism Drosophila melanogaster and six related species. I confirmed that the D. melanogaster sex comb, although longitudinal in the adult, originates in a transverse orientation and rotates during development, and showed that this process occurs through male-specific convergent extension. However, in the species that I examined that have longitudinally-oriented sex combs that extend the full length of the tarsus, including D. ficusphila and two species of the montium subgroup, the sex comb does not rotate, and instead forms from two longitudinal rows that converge during development. Another species of the montium subgroup, D. nikananu, has a sex comb that is convergently similar to D. melanogaster, but forms in a manner typical of its subgroup, showing that very similar combs can be formed through different processes. In all species, there is a strong correlation between the position of the sex comb and the transverse bristle row on the foreleg tarsus just proximal to it. To test whether it is possible to violate this apparent constraint on development, I perturbed the expression of the leg patterning gene dachshund to generate ectopic sex combs in D. melanogaster. I found that while most patterns showed the same correlation, a few circumvent the constraint. I also demonstrated that the ectopic combs were formed non-autonomously and that overexpression of dachshund can transform certain aspects of the sex comb phenotype to resemble the transverse bristles to which they are homologous.

Anacampserotaceae pertence à ordem Caryophyllales, subordem Portulacineae, atualmente constituída por três gêneros (Anacampseros L., Grahamia Gill ex Hook e Talinopsis A. Gray) antes pertencentes à família Portulacaceae. Os representantes de Anacampserotaceae apresentam estruturas axilares lignificadas muito características, como tricomas, escamas (scales) e cerdas (bristles) e também apresentam células do tipo WBT que ocorre somente em mais outras duas famílias de Caryophyllales, Aizoaceae e Cactaceae. Os caracteres axilares são muito informativos para o clado ACPT (Anacampserotaceae, Cactaceae, Portulacaceae e Talinaceae) e vêm revelando importantes dados aos estudos filogenéticos da subordem Portulacineae, no entanto, há uma controvérsia quanto a origem ontogenética das estruturas axilares de Anacampserotaceae, o que pode levar a interpretações equivocadas das relações filogenéticas do grupo. Diante disso, este trabalho realizou um estudo ontogenético das estruturas presentes na região da axila foliar de oito espécies de Anacampserotaceae e analisou as WBTs do caule e de folhas quanto seu tipo de espessamento e medidas quantitativas de seis espécies. Os resultados apontam a 1) origem estipular das escamas e não protodérmica, como mencionado na literatura; 2) primeiro relato de profilos na família e 3) WBTs ocorrem em Anacampseros e estão ausente em Talinopsis, grupo considerado basal na família. / Anacampserotaceae belongs to the order Caryophyllales, suborder Portulacineae, currently consists of three genus (Anacampseros L., Grahamia Gill ex Hook and Talinopsis A. Gray) formerly circumscribed to the family Portulacaceae. Anacampserotaceae\'s representative presents lignified axillary structures very distinctive, like trichomes, scales and bristles and also WBT cells that is presented only by two other families of Caryophyllales, Aizoaceae e Cactaceae. The axillary characters are very informative for the ACPT clade (Anacampserotaceae, Cactaceae, Portulacaceae and Talinaceae) and has been revealing important data for the phylogenetic studies on the Portulacineae suborder, nevertheless, there is a controversy regarding the Anacampserotaceae axillary structures ontogenetic origin, what may lead to misguided interpretations for the ACPT phylogenetic relationships. Before it, this research have accomplished the ontogenetic study of the structures present on the leaf axil of eight Anacampserotaceae species and examined stem and leaf WBTs, as for its secondary thickening type and quantitative measurements of six species. The results points 1) that at least one structure (scale) has leaf origin instead of protodermic origin, as stated by some authors; 2) first report of prophylls for the family and 3) WBTs occur in Anacampseros but they are absent in Talinopsis, a basal group of Anacampserotaceae.

No description available.

No description available.