SPARC is a collagen‐binding, matricellular glycoprotein with diverse roles in tissue remodeling and development. Previous studies have demonstrated that SPARC is required in Drosophila for larval development and maintenance of the fat body, an organ that incorporates endocrine, growth and immune functions. I have characterized effects of loss and knockdown of SPARC in the fat body. Loss‐of‐function analyses revealed remodeling of adipocytes demarcated by cell rounding and dense accumulation of extracellular matrix (ECM) beneath an abnormally thick basement membrane. Remodeling of adipocytes mediated by expression of matrix metalloproteinase 2 (MMP2) was found to cause ECM breakdown and accumulation of hemocytes, indicating endogenous fat body remodeling is mechanistically distinct from that which occurs upon silencing of SPARC. Knockdown of the lysyl hydroxylase, dPlod, in the fat body, revealed abnormal intracellular co‐localization of SPARC with Collagen IV, but not with Laminin. The data indicate SPARC is required for ECM homeostasis during development.

SPARC is a highly conserved trimodular Ca2+- and Collagen-binding matricellular protein with diverse functions during development, wound healing and cancer metastasis. Our lab previously generated an embryonic lethal Drosophila SPARC null mutant, Df(3R)nm136, analysis of which revealed that SPARC was required for the deposition of Collagen IV into basal laminae and normal nervous system development during embryogenesis. In contrast to these previous studies, my data revealed that SPARC is not required for the deposition of Collagen IV into embryonic basal laminae or embryonic nervous system development. Further analysis showed that the Df(3R)nm136 chromosome carried a second-site mutation in the Neuralized locus which caused the nervous system defects and embryonic lethality previously associated with a loss of SPARC. Removal of this second site mutation and reanalysis of the SPARC mutant phenotype revealed that SPARC is required for larval development where it appears to play a role in the regulation fat body remodelling. SPARC mutant fat bodies showed changes in cell shape and basal lamina remodelling which resemble the fat body remodelling process that normally occurs during pre-pupal stages via up-regulation of MMP2 in response to the steroid hormone ecdysone. The effects of loss of SPARC on fat body cells were shown to be cell autonomous. Structure-function analysis of SPARC showed that secretion of SPARC is required for its function, whereas Domain1 is dispensable. Together, my studies indicate that SPARC has essential intra and extracellular roles during Drosophila larval fat body development.

SPARC is a highly conserved trimodular Ca2+- and Collagen-binding matricellular protein with diverse functions during development, wound healing and cancer metastasis. Our lab previously generated an embryonic lethal Drosophila SPARC null mutant, Df(3R)nm136, analysis of which revealed that SPARC was required for the deposition of Collagen IV into basal laminae and normal nervous system development during embryogenesis. In contrast to these previous studies, my data revealed that SPARC is not required for the deposition of Collagen IV into embryonic basal laminae or embryonic nervous system development. Further analysis showed that the Df(3R)nm136 chromosome carried a second-site mutation in the Neuralized locus which caused the nervous system defects and embryonic lethality previously associated with a loss of SPARC. Removal of this second site mutation and reanalysis of the SPARC mutant phenotype revealed that SPARC is required for larval development where it appears to play a role in the regulation fat body remodelling. SPARC mutant fat bodies showed changes in cell shape and basal lamina remodelling which resemble the fat body remodelling process that normally occurs during pre-pupal stages via up-regulation of MMP2 in response to the steroid hormone ecdysone. The effects of loss of SPARC on fat body cells were shown to be cell autonomous. Structure-function analysis of SPARC showed that secretion of SPARC is required for its function, whereas Domain1 is dispensable. Together, my studies indicate that SPARC has essential intra and extracellular roles during Drosophila larval fat body development.

Diss. (sammanfattning) Göteborg : Göteborgs universitet, 2008. / Härtill 4 uppsatser.

Dissertation (Ph.D.) -- University of Texas Southwestern Medical Center at Dallas, 2006 / Vita. Bibliography: 118-151.

Using morphometric and cytochemical techniques we have described changes taking place in the fat body cells during three different stages of development. The cell number remains constant at about 2200 cells during larval life and then decreases gradually and continuously throughout metamorphosis and the first 3 days of the adult stage until no more cells can be observed. Cell size increases rapidly during the larval period and decreases steadily during metamorphosis and adult stage. The size of the nuclei increases during the larval instars and decreases during the pupal interval. The change in nuclear size is correlated with the amount of DNA present throughout development implying the nuclear DNA is synthesized during the larval period and degraded gradually during metamorphosis. The cell size changes are due in large part to accumulation or loss of reserve substances: lipid droplets, glycogen deposits and protein granules. During metamorphosis the amount of lipid decreases slightly whereas glycogen experiences two loss cycles. The protein granules in the form of lysosomes continue to increase in amount during the first day of metamorphosis because of a short period of massive autophagy. Then the lysosomes decrease in amount throughout the remainder of metamorphosis. The lysosomes stain positively for lipofuscin.

Aedes aegypti is the primary vector for dengue, zika, chikungunya, and yellow fever viruses. Disease transmission through this mosquito places over 40% of the world's population at risk of contracting one or more of these pathogens. Current control strategies such as insecticide application have failed or carry additional burdens, such as off-target toxicity to mammals and birds. Our lab proposes utilizing a conserved arthropod hormone pathway, juvenile hormone (JH), related to growth and reproduction to curb these vector populations and reduce disease transmission. Additionally, JH is nontoxic to birds and mammals; it requires incredibly high doses to have lethal effects. We hypothesize that JH-responsive genes expressed early in the adult are responsible for her reproductive capacity and by manipulating the signaling downstream of the receptor, we will be able to decrease the female's fecundity and limit vector populations. Via bioinformatics screening of RNA-sequencing data using the New Tuxedo pipeline, we identified 47 potential transcription factor candidates. With the use of in vitro culturing of the mosquito's reproductive tissues in the presence of a translation inhibitor, we identified two early JH responsive gene candidates, FoxA and zinc finger 519, p-value <0.05. The functional characterization of these two remains to be seen, however, in Drosophila melanogaster, they both have roles in chromatin remodeling and require protein partners to carry out long range interactions. / Master of Science in Life Sciences / The mosquito, Aedes aegypti, is responsible for the spread of a myriad of viruses such as dengue, zika, and chikungunya. Currently, these infections have no vaccine or treatment available and transmission rates continue to steeply rise in response to the spread of breeding grounds. Popular insecticides carry detriments such as off-species toxicity and continuous application to treatment areas. Our lab proposes an alternative to these chemical insecticides by manipulating a developmental pathway in the mosquito. The Juvenile Hormone pathway is conserved in arthropods, responsible for growth and reproduction, and the hormone is nontoxic to mammals. Through the combination of bioinformatics and genomics studies, we have identified two JH-responsive gene candidates that are potential regulators of this pathway.

Made available in DSpace on 2015-03-04T20:05:59Z (GMT). No. of bitstreams: 0 Previous issue date: 8 / Nenhuma / Esta dissertação é produto de uma pesquisa realizada com o propósito de analisar como professoras que atuam nas séries iniciais do Ensino Fundamental descrevem as crianças que ocupam a posição de ser/estar gordas, buscando compreender algumas das implicações dessas descrições para a educação nutricional escolar. A expressão ser/estar gorda foi utilizada para atribuir ao corpo gordo um caráter não essencialista, não fixo, não depositando um olhar sob o corpo gordo na ótica do discurso médico, com base em medidas antropométricas. O material de pesquisa analisado consiste em entrevistas com estudantes do Curso de Pedagogia da Universidade Regional Integrada do Alto Uruguai e das Missões - URI, alunas de Fundamentos Teóricos e Metodológicos de Nutrição e Saúde - FTM de Nutrição e Saúde e que atuam como professoras. A produção do material de pesquisa, assim como sua análise, foram realizadas tendo como apoio as teorizações do campo dos Estudos Culturais, em uma perspectiva pós-estruturalista, na vertente vinculada / This study is the product of a research which aims to analyze how teachers who work in elementary schools describe children who are fat, trying to understand some of the implications of these concepts for an improvement in nutritional education in schools. The expression to be fat is being used to attribute to a fat body a non- essentialist character, not fixed, not assuming a medical view based on anthropometric measures. The research material analyzed consists of interviews with undergraduate students of Pedagogy belonging to the Universidade Regional Integrada do Alto Uruguai e das Missões as well as Nutrition and Health graduates who work as teachers. The research material as well as its analysis has been undertaken based on Cultural Studies of post-structural theories linked to Michel Foucault. The research presents some considerations on how the medical discourse creates obesity and its implications. It discusses the fat body, how a fat body is referred to in post-modern times, as well as when thinn

<b>Background</b>: Fetal growth restricted (FGR) infants have increased perinatal morbidity and mortality risks. Standard fetal biometry may identify some FGR babies; amniotic fluid measurement and Doppler assessment of blood vessels provide additional, functional assessments, but are often normal in babies with late-onset FGR who are difficult to diagnose. A marker reflecting nutritional status should help to identify FGR fetuses, enabling effective intervention: increased monitoring or delivery and neonatal management. Arm and/or thigh measurements have previously shown potential in 2D and 3D. Limb fat volume has never been measured and could provide an in utero marker of fetal nutritional status. <b>Aims</b>: 1. To develop an ultrasound scanning protocol to acquire 2D images and 3D volumes of fetal arms and thighs. 2. To develop method(s), suitable for use in clinical practice, to measure fat in these images and volumes. 3. To assess the reproducibility of these methods. 4. To assess the validity of these methods by comparing them with MRI images of fetal limb fat. 5. To use these methods in a healthy population to develop reference ranges. 6. To correlate these methods with validated neonatal measurements, to assess whether the antenatal methods reflect neonatal body composition. 7. To apply these methods to longitudinal prospective ultrasound images from multiple countries to assess SGA fetuses. <b>Method</b>: Ultrasound imaging protocols were developed to obtain accurate images and volumes of fetal arms and thighs. Segmentation tools were designed with biomedical engineers to measure fat, lean and limb compartments, and applied to 2D images and 3D volumes (n=500), with calculation of reference centiles in optimally healthy women (INTERGROWTH-21st study) and MRI validation of the ultrasound measurements. Additional methods were assessed: a two-ellipse method, and a three-thickness Fetal Fat Index (FFI). Reproducibility was assessed using Bland-Altman plots and ICCs. Fetal measurements were correlated with neonatal body composition data and anthropometry. Third trimester fetal thigh fat volumes were compared in sub-cohorts of AGA and SGA fetuses. <b>Results</b>: Reference centiles were calculated for novel fractional arm and leg volumes (fat and lean), from 16 to 41 weeks. 2D reference ranges were also calculated. The FFI technique - quick, simple, 2D - correlated well with fat area and fat volume. DXA analyses showed a strong correlation between neonatal limb and whole body fat. Correlation analyses showed that infants with above- and below-average arm circumferences have significantly different amounts of arm fat as early as 30-35 weeks. The strength of correlation between antenatal limb fat and neonatal PEA POD whole body fat increased with increasing gestational age. Scans at 30-34 weeks showed a significant difference in fractional thigh fat between those who would be born SGA compared with AGA. <b>Conclusion</b>: This thesis explores, in detail, the measurement of fetal arm and thigh fat using 2D and 3D ultrasound, and demonstrates that it is correlated to neonatal body composition thus allowing 'fetal body composition' to be established as a research tool; the ultimate aim is to be able to distinguish growth-restricted fetuses from those of normal nutritional status. Novel measurements have been developed, acquisition protocols described, reproducibility assessed, and reference centiles calculated in an optimally healthy population: 2D Fetal Fat Index, 3D fractional limb fat and lean volumes, and limb fat (2D and 3D) as a percentage.

Made available in DSpace on 2014-06-11T19:30:56Z (GMT). No. of bitstreams: 0 Previous issue date: 2007-10-11Bitstream added on 2014-06-13T19:19:43Z : No. of bitstreams: 1 roma_gc_dr_rcla.pdf: 2022594 bytes, checksum: eece8bf27b13004335d7c54d03d168df (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / O corpo gorduroso dos insetos é um tecido de preenchimento que está principalmente no abdômen e ao redor dos órgãos, onde é denominado de corpo gorduroso perivisceral, e logo abaixo do tegumento, ou corpo gorduroso parietal. No presente estudo avaliou-se a morfologia, a morfometria, a histoquímica e a citoquímica ultra-estrutural, além da química dos lipídios, das células do corpo gorduroso das operárias e gynes (fêmeas aladas) de formigas de Cyphomyrmex rimosus e de Mycetarotes parallelus e operárias médias e rainhas de Acromyrmex disciger e de Atta laevigata pertencentes à tribo Attini, com o objetivo de descrever os tipos celulares e analisar morfológica e fisiologicamente suas células, com vistas a detectar a ocorrência de possíveis variações neste tecido tanto entre as espécies quanto entre as castas, além de avaliar se existiriam diferenças entre as espécies basais e derivadas que possivelmente teriam surgido ao longo do processo evolutivo dos indivíduos pertencentes a esta tribo. Os resultados mostraram que em todas as espécies e castas o corpo gorduroso é constituído pelos trofócitos, células que se tornam poligonais devido à compressão de uma contra a outra, com núcleos irregulares e com presença de proteínas, polissacarídeos neutros e lipídios distribuídos por todo o citoplasma. Nas gynes e rainhas, em geral, esses elementos mostraram-se mais evidentes do que nas operárias. Verificou-se ainda que os trofócitos das castas reprodutivas seriam caracterizados pela presença de toda a estrutura relacionada à síntese de proteínas, elementos essenciais nos processos relacionados à vitelogênese. Os lipídios nos trofócitos das operárias e rainhas das espécies derivadas apareceram em maiores quantidades do que nas operárias e gynes basais. Os enócitos, outro tipo celular freqüentemente associado aos trofócitos, mostraram-se... / The insect fat body is a filling tissue which is distributed principally in the abdomen, around the organs (also known as perivisceral fat body) and right above the tegument (called the parietal fat body). The present study evaluated the morphology, morphometry, histochemistry and ultrastructural cytochemistry, as well the lipid chemistry, of the fat body cells of ant workers and gynes (winged females) of Cyphomyrmex rimosus and Mycetarotes parallelus and media workers and queens of Acromyrmex disciger and Atta laevigata belonging to the Attini tribe, with the objective of describing the cell types and the morphological and physiological analysis of their cells. This was done in an attempt to detect the occurrence of possible tissue variations between the species and castes, as well as evaluating if there are differences between the basal and derived species that may have surfaced during the evolution of these individuals belonging to this tribe. The results showed that in all species and castes the fat body is constituted of trophocytes, which are polygonal in shape due to the compression of one cell against another, and with irregular nuclei, proteins, neutral polysaccharides and lipids distributed all over the cytoplasm. In general, these elements were more evident in the gynes and queens than in the workers. It was also verified that the trophocytes of the reproductive castes are characterized by the presence of structures related to protein synthesis, essential elements in activities related to vitellogenesis. The lipids in the worker and queen trophocytes from the derived species are present in larger amounts when compared to the basal workers and gynes. The oenocytes, another cell type frequently associated to the trophocytes, are spherical in all species and castes, in addition to spherical nuclei, proteins, lipids and a few neutral polysaccharides distributed all over the... (Complete abstract click electronic access below)