Dissertations / Theses on the topic 'Lipid deposition'

Type 2 diabetes mellitus (T2DM) is associated with an increased risk of heart failure and cardiovascular mortality even in the absence of coronary artery disease. Although the reasons for this are not clear, impaired cardiac high energy phosphate metabolism, coronary microvascular dysfunction and ectopic lipid deposition have emerged among the candidate mechanisms. Cardiac magnetic resonance imaging (CMR) and magnetic resonance spectroscopy (MRS) are powerful tools to characterise these conditions. The findings here suggest that, in diabetes, coronary microvascular dysfunction may potentially exacerbate derangement of cardiac energetics under conditions of increased workload. The relationships amongst ectopic adiposity (myocardial, epicardial and hepatic), myocardial metabolic changes and left ventricular remodelling in T2DM were determined using proton magnetic resonance spectroscopy (1H-MRS), cardiac computer tomography (CT) and multi-parametric liver MR. It was found that cardiac steatosis independently predicted left ventricular concentric remodelling and impairment of systolic strain in patients with T2DM. This work also demonstrated that ectopic adiposity is linked to insulin resistance, liver fibrosis and inflammation, and cardiac contractile dysfunction in diabetes, and that the coexistence of obesity and T2DM leads to higher epicardial fat volumes and significant non-alcoholic fatty liver disease compared to T2DM alone. These findings suggest that, since cardiac steatosis and ectopic adiposity are modifiable, strategies aimed at reducing myocardial triglyceride levels may reverse concentric remodelling and improve contractile function in the diabetic heart. The work on field strength effects on cardiac 31P-MRS has shown that 7T is feasible and reliable with reduced error and increased signal to noise compared to 3T. In summary, the work in this thesis demonstrates the powerful role of CMR and MRS in elucidating the detrimental effects that originate from the metabolic abnormalities in the diabetic heart.

Silicone Hydrogel (SiHy) contact lenses are highly successful compared to previous soft lenses; they were developed to provide superior oxygen permeability. However, the hydrophobic natures of the silicone segments enhance lipid sorption which may diminish the lens surface wettability, clarity and comfort. While lens and lens care product are designed to remove lipid deposition, there is lack of experimental evidence to evaluate the actual performances with respect to lipid removal. An in vitro model using an artificial tear fluid containing radiolabeled lipids was employed in this thesis research to evaluate the efficacy of different multi-purpose lens care solutions in removing lipids from SiHy contact lenses. Additional rubbing with the lens care solution is often encouraged by professionals. Part of this research evaluated the effect of additional rubbing process on lipid removal. Overall, a multi-purpose solution (MPS) for lens care, Opti-Free PureMoist®, removed the most lipid deposition from lenses (senofilcon A, comfilcon A, and balafilcon A and one conventional hydrogel lens polymacon). The overall removal percentages were approximately 55% of DPPC and 28% of cholesterol from a conventional hydrogel. However, the MPSs did not remove lipids effectively from SiHy lenses. The highest percentages of removal were 3.08% of DPPC and 0.76% of cholesterol from SiHy lotrafilcon B lenses with Opti-Free PureMoist. The rubbing process increased the amount of removal in some MPSs, but the effects were small. The lack of removal of lipid suggests that the surfactants in the MPSs are not hydrophobic enough to remove lipids from SiHy lenses. Apparently a majority of deposited lipids absorbed into the lens matrix as rubbing did not enhance removal significantly. Future study on determining the concentration profile of lipid sorption throughout the lens thickness is encouraged. Another topic in this research thesis is the use of hydrogel lenses to deliver comfort agents or lubricating molecules from lenses. A screening study was performed in this research to select possible agents to be loaded into several SiHy macromer formulations. Experiments showed that comfort agents PNVP and Kollidon were the best candidates for such a procedure.

Os objetivos deste estudo foram: (1) avaliar os efeitos da inclusão de níveis crescentes de &beta;-ácidos do lúpulo (Humulus lupulus) ou de um antimicrobiano melhorador do desempenho (colistina) na dieta sobre o desempenho zootécnico, digestibilidade de nutrientes e energia da dieta, ocorrência de diarreia, refugagem de leitões, explosão respiratória, peso de órgãos e histologia e diversidade microbiana do intestino de leitões recém-desmamados, assim como testar in vitro a sensibilidade de bactérias aos &beta;-ácidos; e (2) avaliar os efeitos da inclusão de níveis crescentes de &beta;-ácidos na dieta sobre atributos físicos, oxidação lipídica e composição do músculo Longissimus. Foram utilizados 200 leitões recém-desmamados (6,23±0,32 kg) em um experimento em blocos completos casualizados com 5 tratamentos, 8 repetições e 5 leitões por unidade experimental (baia). Os leitões foram alimentados com dietas suplementadas com 0 (controle negativo), 120, 240 ou 360 mg/kg de &beta;-ácidos ou com 40 mg/kg de colistina (tratamento antimicrobiano) durante 35 dias. No 7º e 35º dias do experimento, um macho castrado por baia foi sacrificado para avaliação do peso de órgãos (estômago, pâncreas, fígado, intestino delgado e baço), histologia do intestino delgado (altura de vilosidade e profundidade de cripta) e diversidade microbiana do intestino (PCR-DGGE), além da coletada do músculo Longissimus para análises da carne. ANOVA e contrastes ortogonais foram utilizados para determinar o efeito dos níveis de &beta;-ácidos na dieta sobre as variáveis, assim como comparar o tratamento antimicrobiano com cada um dos outros tratamentos. O aumento dos níveis de &beta;-ácidos na dieta melhorou linearmente (P<0,05) o peso vivo, o ganho de peso, a eficiência alimentar e a digestibilidade aparente do extrato etéreo da dieta. O tratamento antimicrobiano melhorou (P<0,03) o peso vivo, o ganho de peso e a eficiência alimentar comparado ao controle negativo, porém não afetou (P>0,05) a digestibilidade dos nutrientes e da energia da dieta. Não foram observados efeitos (P>0,05) dos tratamentos sobre o consumo de ração. De maneira geral, a ocorrência de diarreia foi menor (P<0,01) nos tratamentos antimicrobiano, controle negativo e 360 mg/kg de &beta;-ácidos do que nos tratamentos 120 e 240 mg/kg de &beta;-ácidos, enquanto não foram identificados leitões refugos durante todo o período experimental. Não foram observados efeitos (P>0,05) dos tratamentos sobre a explosão respiratória no sangue, peso dos órgãos, histologia do intestino delgado e diversidade da microbiota intestinal. Apenas Staphylococcus aureus foi sensível aos &beta;-ácidos, enquanto Escherichia coli, Salmonella enteritidis, Salmonella typhimurim e Enterococcus faecalis foram resistentes. Não foram observados efeitos (P>0,05) dos níveis de &beta;-ácidos sobre os atributos físicos da carne. Foi observado efeito quadrático (P<0,05) dos &beta;-ácidos sobre os conteúdos de gordura, proteína e TBARS da carne, sendo que os níveis calculados 176, 150 e 181 mg/kg de &beta;-ácidos resultaram, respectivamente, em 16,20% de redução na gordura, 1,95% de aumento da proteína e 23,31% de redução de TBARS. Portanto, a inclusão de &beta;-ácidos do lúpulo até 360 mg/kg na dieta demonstrou ser eficiente como alternativa aos antimicrobianos melhoradores do desempenho, bem como potencial de reduzir gordura, aumentar proteína e prevenir oxidação lipídica da carne.<br>The purposes of this study were: (1) to evaluate the effects of dietary graded levels of hop (Humulus lupulus) &beta;-acids or antimicrobial growth promoter (colistin) on growth performance, nutrients and energy digestibility, diarrhea occurrence, unthrifty pigs, respiratory burst, organ weights, small intestine histology, and intestine microbial diversity of weanling pigs, as well as in vitro bacteria sensitivity to hop &beta;-acids; and (2) to evaluate the effects of dietary hop &beta;-acids on physical attributes, lipid oxidation, and composition of Longissimus muscle. Two hundred weanling pigs (6.23±0.32 kg BW) were used in a randomized complete block design experiment with 5 treatments, 8 replications, and 5 pigs per experimental unit (pen). Pigs were fed diets supplemented with 0 (negative control), 120, 240, or 360 mg/kg hop &beta;-acids, or with 40 mg/kg colistin (antimicrobial treatment) during a 35d. On days 7 and 35 of the experiment, one castrated male from each pen was slaughtered to evaluate organ weights (stomach, pancreas, liver, small intestine, spleen), small intestine histology (villus height and crypt depth), and intestine microbial diversity (PCR-DGGE), as well to sample Longissimus muscle for meat analysis. ANOVA and orthogonal contrasts were performed to determine the effects of dietary hop &beta;-acids levels (0, 120, 240, and 360 mg/kg) on all variables, as well as to compare the antimicrobial treatment with all other treatments. Increasing dietary levels of hop &beta;-acids linearly improved (P<0.05) BW, ADG, G:F, and apparent digestibility of ether extract of weanling pig diets. The antimicrobial treatment improved (P<0.03) BW, ADG, and G:F compared to negative control, but did not affect (P>0.05) nutrients and energy digestibility. No effects (P>0.05) of treatments were observed on ADFI. Overall, the diarrhea occurrence was lower (P<0.01) for antimicrobial treatment, negative control, and 360 mg/kg hop &beta;-acids than for 120 and 240 mg/kg hop &beta;-acids, while no unthrifty pigs were identified throughout all experimental period. No effects (P>0.05) of dietary treatments were observed on blood respiratory burst, organ weights, small intestine histology, and intestine microbial diversity. Staphylococcus aureus was sensitive, while Escherichia coli, Salmonella enteritidis, Salmonella typhimurim, and Enterococcus faecalis were resistant to hop &beta;-acids. No effects (P>0.05) of hop &beta;-acids were observed on meat physical attributes. Quadratic effects (P<0.05) of hop &beta;-acids were observed on fat, protein, and TBARS-values of meat, showing that dietary levels of 176, 150 and 181 mg/kg hop &beta;- acids provided, respectively, 16.20% fat reduction, 1.95% protein accretion, and 23.31% TBARS reduction. Therefore, dietary hop (Humulus lupulus) &beta;-acids up to 360 mg/kg showed to be efficient as an alternative to antimicrobial growth promoters for weanling pigs, as well to reduce fat, increase protein, and prevent lipid oxidation of meat.

La present Tesi Doctoral s’emmarca dins d’una línia d’investigació dedicada a l’estudi de les bases genètiques del metabolisme dels greixos en relació a la producció de carn de porcí d’alta qualitat i saludable. L’objectiu final és la identificació de polimorfismes i mecanismes de regulació responsables de la variabilitat genètica d’aquests caràcters complexes en l’espècie porcina. En aquest context, s’han utilitzat mètodes de genòmica estructural (mapes de QTL d’expressió (eQTL); estudis de gens candidats) i funcional (estudis d’expressió gènica) a més a més d’anàlisis proteics i cel·lulars en mostres de múscul i greix de porcs seleccionats per les seves característiques de qualitat de carn. Així, mitjançant la tècnica de microarrays s’ha analitzat el patró d’expressió d’ARNm en mostres de múscul gluteus medius obtingudes a partir de porcs d’una població comercial Duroc amb fenotips divergents per diversos paràmetres relacionats amb la deposició dels lípids. Com a resultat, s’han observat nombrosos gens diferencialment expressats entre els animals amb perfils divergents d’engreixament. Un estudi ontològic/funcional va revelar que aquests gens estaven particularment relacionats amb el metabolisme lipídic, el creixement i la diferenciació muscular, la immunitat i la captació de glucosa en la ruta de la insulina. D’altra banda, les anàlisis d’eQTL han revelat l’existència de regions genòmiques responsables de la variació de l’expressió gènica en el múscul gluteus medius porcí; algunes de les quals mostren una concordança posicional amb varis QTL per caràcters de qualitat de cran i engreixament detectats prèviament a la mateixa població Duroc. Complementàriament, s’ha realitzat un estudi més exhaustiu de quatre gens candidats (ACACA, HMGCR, SCD i 6D), directament implicats en caràcters relacionats amb la qualitat de la carn al ser els principals responsables de la síntesis i dessaturació d’àcids grassos i colesterol. Combinant els resultats de l’anàlisi d’expressió gènica, mapes d’eQTL i els gens candidats estudiats s’ha elaborat una llista de gens candidats funcionals i posicionals que serà la base de futures investigacions cap a l’establiment de les xarxes gèniques i els mecanismes moleculars implicats en el metabolisme dels lípids musculars i els caràcters relacionats amb la qualitat de la carn en porcí.<br>La presente Tesis Doctoral se enmarca en una línea de investigación dedicada al estudio de las bases genéticas del metabolismo de las grasas en relación a la producción de carne de porcino de alta calidad y saludable. El objetivo final es la identificación de polimorfismos y mecanismos de regulación responsables de la variabilidad genética de estos caracteres complejos en porcino. Para ello se han utilizado métodos de genómica estructural (mapas de QTL de expresión (eQTL); estudio de genes candidatos) y funcional (estudios de expresión génica) y también de análisis proteico y celular en muestras de músculo y grasa de cerdos seleccionados por sus características de calidad de carne. Así, mediante la técnica de microarrays se ha analizado el patrón de expresión de ARNm en muestras de músculo gluteus medius obtenidas a partir de cerdos de una población comercial Duroc con fenotipos divergentes para varios parámetros relacionados con la deposición de los lípidos. Como resultado, se han observado numerosos genes diferencialmente expresados entre los animales con perfiles divergentes de engorde. Un estudio ontológico/funcional mostró que estos genes estaban particularmente relacionados con el metabolismo lipídico, el crecimiento y la diferenciación muscular, la inmunidad, y la captación de glucosa en la ruta de la insulina. Por otra parte, un análisis de eQTL ha revelado la existencia de regiones genómicas responsables de la variación de la expresión génica en el músculo gluteus medius porcino, algunas de las cuales muestran una concordancia posicional con varios QTL para caracteres de calidad de carne y engorde detectados previamente en la misma población Duroc. Complementariamente, se ha realizado un estudio más exhaustivo de cuatro genes candidatos (ACACA, HMGCR, SCD y 6D) directamente implicados en caracteres relacionados con la calidad de la carne al ser los principales responsables de la síntesis y desaturación de ácidos grasos y colesterol. Combinando los resultados del análisis de expresión génica, mapas de eQTL y los genes candidatos estudiados se ha elaborado una lista de genes candidatos funcionales y posicionales que será la base de futuras investigaciones hacia el establecimiento de las redes génicas y los mecanismos moleculares implicados en el metabolismo de los lípidos musculares y los caracteres relacionados con la calidad de la carne en porcino.<br>This PhD is part of a line of research devoted to studying the genetic basis of lipid metabolism and fat deposition in pigs with a view to producing healthy and high quality meat. The main objective is the identification of polymorphisms and regulatory mechanisms responsible for the genetic variability of these complex characters in pigs. In this sense, we have used several methods in the fields of structural (expression QTL (eQTL) maps; candidate genes studies) and functional (gene expression studies) genomics and also protein and cell studies in muscle and fat samples from pigs selected by meat quality parameters. In this context, using microarrays we analyzed the mRNA expression pattern in gluteus medius muscle samples obtained from a commercial Duroc pig population with divergent phenotypes for several parameters related to lipid deposition. As a result, we have obtained a list of genes differentially expressed between animals with divergent profiles related to lipid deposition. The ontological/functional study showed that these genes were particularly related to lipid metabolism, growth and muscle differentiation, immunity and glucose uptake in the insulin pathway. Moreover, analysis of eQTL has revealed the existence of genomic regions responsible for the variation of gene expression in porcine gluteus medius muscle. Some of these eQTL show positional concordance with several QTL related to meat quality and fat deposition previously identified in the same Duroc population. Additionally, we have performed a comprehensive study of four candidate genes (ACACA, HMGCR, SCD and 6D) directly involved in traits related to meat quality, playing an important role in fatty acids and cholesterol synthesis and desaturation. Combining the results of gene expression analysis, eQTL maps and candidate genes studied have resulted in a list of functional and positional candidate genes representing a valuable contribution to the understanding of the genetic regulation of skeletal muscle individual gene expression in swine species. This is a first step towards disentangling gene networks and molecular mechanisms involved in muscular lipid metabolism and meat quality traits in pigs.

Foram realizados dois ensaios experimentais a fim de avaliar diferentes níveis de lisina digestível e zinco quelato para frango de corte macho, da linhagem Ross na fase dos 22 aos 42 dias de idade. O delineamento experimental foi inteiramente casualizado em arranjo fatorial 5 x 2, cinco níveis de lisina e dois níveis de zinco 43 e 243ppm. As dietas foram formuladas para conter 3.150 kcal de EM/kg e 19% de PB. No ensaio I, os níveis de lisina digestível foram 0,841, 0,874, 0,995, 1,019 e 1,028%, aplicados a três unidades experimentais. A unidade experimental correspondeu a 1 boxe com 30 frangos com peso médio inicial de 957,38g. Avaliaram-se características de desempenho, rendimento de cortes e composição corporal. No ensaio II, os níveis de lisina digestível foram 0.779, 0,825, 0,961, 1,066 e 1,222%, aplicados a seis repetições. A unidade experimental correspondeu a uma gaiola com três animais com peso médio inicial de 866,22g. Determinou-se, nesse estudo, o balanço de nitrogênio e a digestibilidade das dietas. Constatou-se interação do nível de lisina e zinco nas variáveis: peso final, ganho de peso, conversão alimentar, matéria seca ingerida, nitrogênio ingerido, energia bruta ingerida, energia bruta excretada e balanço energético. Porcentagem de peito e porcentagem de coxa e sobrecoxa foram crescentes pelo aumento na concentração de lisina digestível na dieta, seguindo equação linear. O melhor nível de lisina, de acordo com o desempenho, foi de 1,06% de lisina total ou 0,93% de lisina digestível para dietas com 43ppm de zinco. Para dietas com 253ppm, a exigência de lisina digestível foi igual ou maior que 1,028%.<br>In order to evaluate the different levels of digestible lysine and zinc chelate effect on Ross male broiler chicken from 22 to 42 days of age, two trials were carried out. The experimental design was completely randomized with a 5x2 arrangement, with treatments consisting of five levels of lysine and two levels of zinc chelate (43 and 243ppm). All diets contained 3,150 kcal of ME/kg and 19% of crude protein. In trial I, a 30 poultry pen was considered one experimental unit and three pens received the following lysine levels: 0.841, 0.874, 0.995, 1.019 and 1.028%. Average weight at pen was 957.38g. For this trial, parameters evaluated were: performance traits, cut yield and body composition. In trial II, each three birds cage, weighting 866.22g in average, was considered one experimental unit. Birds were fed in repetition another five lysine levels: 0.779, 0.825, 0.961, 1.066 and 1.222%. In this latter trial, data on nitrogen-balance and diets digestibility were determined. Interaction between lysine and zinc chelate was observed for weight at day 42, weight gain, feed:ration gain, dry matter intake, nitrogen intake, crude energy intake, crude energy excreted and energy balance. There was an increasing in breast, thigh and drumstick percentage concomitant with the increase of lysine levels on diet, following a linear equation. The most effective lysine level, accordingly to performance traits, was 1.06% of total lysine, or 0.93% of digestive lysine, when the zinc chelate level was 43ppm. A 253ppm diets required lysine levels of 1.028% or greater.

En s'inspirant des processus transmembranaires de transport d'ions à l'œuvre dans les cellules vivantes, la conception d'une pile biomimétique peut être envisagée. Le principe de cette pile est d'utiliser les gradients de concentration en ions ou en protons induits par la protéine NhaA, un antiport transmembranaire Na+/2H+, pour générer de l'énergie électrique. Cette thèse contribue à l'élaboration de cette pile à travers des modifications d'électrodes permettant de détecter l'activité de transporteurs ioniques à l'interface électrode / membrane biomimétique. Une revue bibliographique des aspects fondamentaux des membranes cellulaires et du principe de la pile est présentée. Des électrodes modifiées par électrodéposition de dérivés d'acides salicyliques ont permis l'obtention de films redox-actifs sensibles aux variations de pH ou à la concentration en ions monovalents et monoatomiques. La stabilité du dépôt lipidique sur électrode a été significativement augmentée par l'électro-greffage de la 4-decylaniline. Ce dépôt lipidique stable dans le temps permet d'obtenir des membranes biomimétiques et l'insertion de transporteurs ioniques. L'activité des transporteurs ioniques insérés dans les membranes biomimétiques est suivi à travers les variations de potentiel dépendant du pH ou de la concentration en ions sodium ou potassium à l'interface électrode/membrane<br>Based on the transmembrane ion transport processes of living cells, the design of a biomimetic fuel cell can be considered. Its principle relies on ion or proton concentration gradients induced by the protein NhaA, a transmembrane Na+/2H+ antiport, to generate electrical energy. This thesis contributes to the development of this device through electrode modifications to detect the activity of ionic transporters at the electrode/biomimetic membrane interface.A bibliographic review of the fundamental aspects of cell membranes and of the biomimetic fuel cell principle is presented. Electrodes modified by electrodeposition of salicylic acid derivatives have yielded redox-active films sensitive to pH changes or monovalent and monoatomic ions concentration. The stability of the lipid deposit onto the electrodes was significantly increased by the electrografting of 4-decylaniline. This anchored and stable lipid deposit makes it possible to obtain biomimetic membranes allowing the insertion of ionic transporters. The activity of the ion carriers inserted into the biomimetic membranes has been monitored through the redox-active films' potential that is dependent on pH or on sodium or potassium ions concentrations at the electrode/membrane interface

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, and Woods Hole Oceanographic Institution, 1990.<br>Vita.<br>Includes bibliographical references. Includes bibliographical references.<br>by Mark A. McCaffrey.<br>Ph.D.

The amount of intramuscular fat can influence the sensory characteristics and nutritional value of beef, thus the selection of animals with adequate fat content for consumer becomes important. Intramuscular fat is a complex trait that is difficult to measure and there is growing knowledge about the genes and pathways that control the biological processes involved in fat deposition in muscle. MicroRNAs (miRNAs) are well conserved class of non-coding small RNAs that modulate gene expression of a range of functions in animal development and physiology. This study aimed to identify differentially expressed (DE) miRNAs, regulatory candidate genes and co-expression networks using mRNAs and miRNAs expression data from the Longissimus dorsi muscle of 30 Nelore steers with extreme genomic estimated breeding values (GEBV) for intramuscular fat (IMF) content. The differential expression analysis between the miRNA data from animals with extreme GEBV values for IMF identified six DE miRNAs. Functional annotation of target genes for these microRNAs indicates that PPARs signaling pathway is involved with IMF deposition. Regulatory candidate genes such as SDHAF4, FBXO17, ALDOA and PKM were identified by partial correlation with information theory (PCIT), phenotypic impact factor (PIF) and regulatory impact factor (RIF) approaches from integrated miRNAs-mRNAs expression data. Two DE miRNAs, bta-miR-143 and bta-miR-146b, upregulated in Low IMF group, were also correlated with regulatory candidate genes, which were functionally enriched for GO terms for fatty acids oxidation. Co-expression networks identified several modules related to immune system, protein metabolism, energy metabolism and glucose catabolism by weighted correlation network analysis (WGCNA), which showed possible interaction and regulation between mRNAs and miRNAs. This study contributes to our understanding of regulatory mechanisms of gene signaling networks involved in fat deposition process. Glucose metabolism and inflammation process were the main pathways found in integrative mRNAs-miRNAs analysis and showed to influence intramuscular fat content in beef cattle.<br>A quantidade de gordura intramuscular pode influenciar as características sensoriais e o valor nutricional da carne bovina, assim, a seleção de animais com conteúdo de gordura adequado para o consumidor torna-se importante. A gordura intramuscular é uma característica complexa, de difícil medição e há um conhecimento crescente sobre os genes e vias que controlam os processos biológicos envolvidos na deposição de gordura no músculo. MicroRNAs (miRNAs) são uma classe bem conservados de pequenos RNAs não-codificantes, que modulam a expressão gênica de uma gama de funções no desenvolvimento e fisiologia animal. Este estudo objetivou identificar miRNAs diferencialmente expressos (DE), genes reguladores candidatos e redes de co-expressão usando dados de expressão de mRNAs e miRNAs do músculo Longissimus dorsi de 30 novilhos Nelore com valores genéticos genômicos estimados (GEBV) extremos para conteúdo de gordura intramuscular (IMF). A análise de expressão diferencial entre os dados de miRNA de animais com valores extremos de GEBV para o IMF identificou seis miRNAs DE. A anotação funcional de genes alvos destes microRNAs indica que a via de sinalização de PPAR está envolvida com a deposição de IMF. Os genes reguladores candidatos, tais como SDHAF4, FBXO17, ALDOA e PKM foram identificados pelas abordagens de correlação parcial com teoria da informação (PCIT), fator de impacto fenotípico (PIF) e fator de impacto regulatório (RIF) a partir de dados integrados de expressão de mRNAs-miRNAs. Dois miRNAs, bta-miR-143 e bta-miR-146b, com alta expressão no grupo de baixo conteúdo de IMF, também foram correlacionados com genes reguladores candidatos, os quais foram funcionalmente enriquecidos para termos GO relacionados a oxidação de ácidos graxos. As redes de co-expressão identificaram vários módulos relacionados ao sistema imunológico, ao metabolismo das proteínas, ao metabolismo energético e ao catabolismo da glicose através da análise ponderada da rede de correlação (WGCNA), que mostrou possível interação e regulação entre mRNAs e miRNAs. Este estudo contribui com a compreensão dos possíveis mecanismos reguladores das redes de sinalização genética envolvidas no processo de deposição de gordura. O metabolismo da glicose e o processo de inflamação foram as principais vias encontrados na análise integrada de mRNA-miRNA e mostraram estar associadas ao conteúdo de gordura intramuscular em bovinos de corte.

Tese de mestrado. Biologia (Ecologia Marinha). Universidade de Lisboa, Faculdade de Ciências, 2013<br>A aquicultura é um dos tipos mais modernos de agricultura praticada no Mundo, sendo uma das respostas para a crescente demanda por produtos de origem animal e seus derivados. Devido à baixa diversidade de espécies produzidas na Europa, surgiu a necessidade de diversificar os produtos atualmente produzidos, com a implementação de novas espécies passíveis de serem criadas a um nível industrial. Nesse contexto, foi proposta a implementação da criação e produção de corvina (Argyrosomus regius), por apresentar características necessárias a uma produção sustentável: requisitos biológicos facilmente atingíveis (crescimento, fecundidade e criação em cativeiro), requisitos tecnológicos (índice de conversão apropriado, ciclo de vida bem conhecido) e requisitos de mercado (penetração de mercado, alto valor comercial e disponibilidade anual), que, em conjunto com um custo de produção reduzido, podem competir com as espécies já cultivadas. A corvina faz parte da família Sciaenidae, sendo uma das maiores famílias de peixes roncadores, incluindo 270 espécies dentro de 70 géneros. São peixes roncadores, porque emitem sons durante a época de desova. Possuem uma ampla distribuição entre as regiões temperadas e tropicais do Mundo, incluindo Portugal, de Norte a Sul. Atualmente já existem sete espécies cultivadas a nível comercial e/ou experimental, das quais a corvina faz parte. A corvina é um peixe teleósteo, sendo um dos maiores membros da família Sciaenidae. Pode crescer mais de 180 cm de comprimento total e peso superior a 50 kg. Tem uma ampla distribuição, estando presente nos mares Mediterrâneo e Negro, na costa Atlântica da Europa e costa oeste africana, onde vivem em estuários e águas costeiras, próximo do fundo ou perto da superfície (profundidades variam de 15 a 200 m). A qualidade da carne é de alto valor nutricional, dando origem ao seu nome latino regius, para qualidade “real” da sua carne. O ciclo de vida já está fechado, com muitas “hatcheries” espalhadas por toda a Europa, sendo a engorda feita com sucesso em jaulas ou tanques (prática realizada nos países do Mediterrâneo, como Grécia, França, Itália, Espanha e Egito). Apesar das técnicas para as diferentes fases de criação estarem bem estabelecidas, a produção ainda não atingiu o seu potencial pleno, principalmente devido aos protocolos alimentares, uma vez que estes são os mesmos utilizados em outras espécies, com requisitos bem conhecidos em termos de nutrientes. É um peixe carnívoro, que, com a alimentação apropriada, consegue atingir 1 kg em menos de um ano (cultivo em jaulas), pelo que um rácio proteína:lípido apropriado será a resposta para esse elevado crescimento. Relativamente à formulação de uma dieta apropriada, o valor de proteína alimentar deverá ser superior a 45%, e o valor de lípidos não superior a 17%, em termos de ração total. Os aminoácidos e os ácidos gordos essenciais fornecidos nas rações permitem criar balanços energéticos que irão sustentar o rápido crescimento da corvina. Os ácidos gordos são colocados nas rações através de óleos de peixe, que contêm ácidos gordos saturados, monoinsaturados e polinsaturados, sendo estes últimos aqueles que possuem efeitos benéficos para o ser humano – ómega-3. Os ácidos eicosapentaenóico (EPA) e docosahexaenóico (DHA) são os principais ácidos gordos fornecidos pelos óleos de peixe, e essenciais a todos os peixes. Hidratos de carbono são utilizados na formulação das rações, servindo como uma fonte de uso limitada para produção de energia, bem como para dar forma e estabilidade às rações. Minerais e vitaminas também são introduzidos nas rações, para suplementar deficiências a esse nível. Para averiguar quais os níveis ótimos de proteínas e lípidos a incluir nas rações de corvina, e averiguar como esses nutrientes são utilizados, foi realizado um ensaio experimental, com duração total de 12 semanas. Cinco dietas isoenergéticas (21,92±0,57 MJ/kg) (média±desvpad) foram criadas, com variações nos níveis de proteína (44% e 50%) e lípidos (12%, 15% e 18%), sendo denominadas de 44L15, 44L18, 50L12, 50L15 e 50L18. O ensaio decorreu desde Setembro/2011 a Dezembro/2011 (63 dias), com um número inicial de 945 peixes (63,66±2,78 g), distribuídos aleatoriamente por 15 tanques de fibra de vidro (volume total de 1500L), em grupos triplicados. Os peixes foram aclimatados durante uma semana, e o ensaio começou posteriormente. Os peixes eram alimentados diariamente, às 9h00 e às 16h (dias de semana) e às 9h e às 13h (fins de semana), sendo a alimentação feita à mão, ad libitum (até à saciação). Foram realizadas quatro amostragens: uma inicial, duas intermédias, e uma final. Em todas houve verificação do peso corporal e tamanho, sendo que na final foram sacrificados 12 peixes, dos quais 6 foram usados para a análise corporal proximal, e outros 6 para análise do conteúdo lipídico das amostras de músculo e fígado (lípidos totais e perfil de ácidos gordos). A análise estatística foi realizada com recurso ao software STATISTICA 11.0, onde os dados foram sujeitos à análise de variância (ANOVA), com p <0,05 e quando normalidade e homocedasticidade eram cumpridas. Caso contrário, testes não paramétricos – análise de variância Kruskal-Wallis – eram realizados para averiguar diferenças. No geral, e tendo em conta os parâmetros de crescimento calculados, a dieta 50L18 apresentou o melhor desempenho, quando comparada com as outras dietas, uma vez que possui os níveis desejados de proteína e de lípidos, com proteína > 45% e lípidos ≈ 17%. Por outro lado, a alimentação 50L12 teve o pior desempenho, principalmente por causa dos baixos níveis de lipídios na dieta. As taxas de SGR (taxa de crescimento específico) devem ser maiores do que 1% / dia, situação alcançada com as dietas 50L15 e 50L18 que possuíam os SGR mais elevados, de 0,99±0,04 e 1,21±0,00, respetivamente. Dentro do grupo com 50% de proteína, a dieta 50L18 apresentou a maior Taxa de Crescimento Diário (DGI): 1,78±0,03 %, a maior Eficiência da Ração (FE): 0,97±0,04, e o maior Rácio de Eficiência Proteica (PER): 2,33±0,09, possuindo o menor valor médio de Rácio de Conversão Alimentar (FCR): 1,04±0,04. O valor de DGI obtido é devido aos elevados valores de proteína e lípido presentes na ração, que acabaram por se refletir num peso final superior aos outros tratamentos. O valor de PER está relacionado com valores elevados de FE, bem como de peso final elevado, situação que se confirmou com esta dieta, visto que os peixes que cresceram mais foram aqueles que se alimentaram mais. O FCR ao ser mais baixo que nas outras dietas indica que, com a mesma quantidade de alimento, a conversão da dieta 50L18 em elementos bio disponíveis é feita com maior eficácia. A dieta 50L18 também foi aquela que apresentou os valores médios mais elevados para a retenção de proteína (42,24±2,50 %) e energia (26,98±0,47 %), bem como para os valores médios de ganho diário de nitrogénio (N) (334,56±8,26 mg/kg/dia) e energia (0,71±0,04 kJ/kg/dia). Com estes valores, fica confirmado que dietas com valores aproximados de 50% proteína são essenciais para o crescimento da corvina. A dieta 50L12 apresentou o pior valor de ganho diário de energia (0,51±0,16 kJ/kg/dia), o que indica que não será apropriada para o cultivo de corvina, inclusive por apresentar uma retenção de lípidos (17,65±13,01 %) bastante inferior aos outros tratamentos. Relativamente à composição proximal dos peixes alimentados com cada dieta experimental, em termos de matéria seca, a dieta 44L18 foi a que apresentou o menor valor médio de proteína (64,97±2,32 %) em oposição à dieta 50L12 (69,94±3,11 %), sendo o valor de lípidos o que mais influencia o valor de proteína presente. A dieta 50L12 apresentou o menos valor médio de lípidos (16,78±2,86 %), sendo ainda menos do que o inicial (19,63±0,14 %), o que indica a má performance desta dieta. Em termos de matéria fresca, as dietas do grupo de 50% proteína possuíram melhor performance que a dieta 44L18, sendo que esta, numa base de matéria fresca de lípidos e de energia, obteve os valores médios mais elevados (6,53±0,94 % e 6,44±0,29 % respetivamente), visto possuir uma elevada concentração de lípidos e um valor mais reduzido de proteína. Em termos de deposição lipídica, o conteúdo lipídico do fígado foi maior no tratamento 50L18 do que no 50L12 (63,11±3,98 % vs. 53,01±7,61 %), mas semelhante ao tratamento 44L18 (58,26 ± 10,05 %). Os valores de lípidos musculares não são significativamente diferentes entre os cinco tratamentos, possuindo um valor médio de 2,3 %. O perfil de ácidos gordos (AG) dos diferentes tratamentos não exibe diferenças significativas, possuindo valores médios de AG saturados ≈32%, AG monoinsaturados ≈20%, de AG polinsaturados ≈43% e a relação (n-3)/(n-6) ≈4,2, sendo valores muito bons. Estes resultados, juntamente com os baixos índices aterogénico e trombogénico, prova que a corvina é uma excelente fonte de ómega-3, essenciais param uma condição cardíaca saudável. Não obstante que a proteína é o ingrediente mais caro na formulação de rações, uma dieta apropriada para a criação de corvina a um nível comercial deverá possuir aproximadamente 50% de conteúdo proteico, e possuir entre 15 a 18% de conteúdo lipídico, sendo estes valores uma boa abordagem para uma dieta ideal que poderia maximizar o crescimento e baixar custos.<br>This study investigates the effects of dietary lipid and protein levels in the growth, feed utilization and body composition of meagre (Argyrosomus regius). Triplicate groups of 945 juvenile fish (63,66±2,78 g average weight±SD) were fed for 63 days five isoenergetic diets (21,79±0,17 kJ) containing 44 and 50% of crude protein, and 12, 15 and 18% of crude lipids, named 44L15, 44L18, 50L12, 50L15 and 50L18. Mean values of fishes fed diet 50L18 were significantly higher than all other treatments, regarding final body weight (136,09±1,00 g), specific growth rate (1,21±0,00 %), daily growth index (1,78±0,03 %) and protein efficiency ratio (2,33±0,09), with the %crude protein in the feed to affect the last to parameters. Voluntary feed index of fish was affected by the %crude lipid in the feed, with diet 44L18 to have significantly higher values (1,28±0,11 %) than diets 44L15 and 50L12. Fish fed diet 50L18 had significantly higher values of food conversion ratio (1,04±0,04) than all diets, except diet 50L12. The retention of dry matter and protein had significant differences, with diet 50L18 to have the highest values (27,60±0,98 % and 42,24±2,50 %, respectively), and to also possess the highest daily gain of nitrogen and energy. No significant differences were found in the values of lipid and energy retention, and in the daily gain of lipid. Significant differences were found between the mean lipid deposition on liver, but not on the muscle samples. The fatty acid profile was not significantly different between treatments, and neither were the Atherogenicity and Thrombogenicity indexes. Overall, the results indicated that the best growth performance was observed in fishes fed the 50L18 diet, but with excessive mesenteric fat deposition in the abdominal wall. In conclusion, meagre feeds should have around 50% crude protein and between 15 to 18% crude lipid.

This study was conducted to determine the influence of factors on the efficiency of protein utilization and the rate of lipid deposition and withdrawal in growing pigs. Two experiments were conducted in total. The first experiment involved fifty-two crossbred entire Large White x Landrace male pigs, individually penned, which were used to test the proposition that the efficiency of protein utilisation is influenced by the body composition of the pig at the start of the trial. The experiment was divided into two phases: in the first period, starting at 20kg liveweight, when 3 pigs were slaughtered to determine the initial body composition of the pigs on the trial, the remaining 48 pigs were divided into three groups, two of which were fed ad libitum, with 11 pigs being offered a feed high in crude protein (HP, 1979 CP/kg) and 19 pigs being offered a low CP (LP, 166g/kg) feed. The remaining 19 pigs were fed HP on a restricted basis; the daily allowance being 0.7 of the mean intake of those pigs fed HP ad libitum. The objective of this initial period was to create three groups of pigs differing in body lipid content. As each pig achieved a protein weight of approximately 5.9kg, predicted to occur when the pigs on the three treatments reached live weights of 35, 39 and 34kg respectively, the pig entered phase 2 of the trial. At this stage three pigs from each treatment (a total of 9 pigs) were slaughtered for carcass analysis, the protein contents being approximately 5.9kg, and lipid contents being 85,98 and 87g/kg for the 3 treatments respectively. During phase 2, the 8 pigs fed HP in phase 1 continued to be fed HP in phase 2; 8 pigs were chosen at random from those fed LP in phase 1 and were allocated the high CP basal feed, while the remaining 8 were given LP; and 8 of the pigs feed-restricted in phase 1 were randomly chosen and fed HP, while the remaining 8 were given LP. All pigs were fed ad libitum during phase 2. Four pigs from each treatment in phase 2 were slaughtered after 1 week and the remaining 4 a week later for analysis of body composition In the first week of the second phase of the trial protein gain was highest (264g/d) on the pigs previously restricted and then fed HP, followed by those previously fed LP and then HP (242g/d), with pigs previously restricted and then fed LP depositing the least amount of protein (192g/d). Pigs fed LP or HP throughout, had protein gains of 217 and 210g/d, respectively. Efficiencies of utilization of dietary protein did not differ significantly between treatments, however, the highest being measured in pigs fed LP throughout (461g/kg), followed in order by those fed LP and then HP (457g/kg), those fed HP throughout (404g/kg), those previously restricted and then fed LP (394g/kg), with those previously restricted and then fed HP being the least efficient (372g/kg). The second experiment involved twenty-six male and twenty-six female crossbred Large White x Landrace pigs, individually penned, which were used to determine the maximum rate at which growing pigs can gain lipid. The experiment was divided into three phases: In the first, starting at 20kg live weight (56 days old), when two males and 2 females were slaughtered to determine the initial body composition of the pigs on the trial, the remaining 24 males and 24 females were randomly allocated to their various treatments. The treatments consisted of a feed high in crude protein (H, 197g/kg), a feed low in CP (L, 166g/kg) and three blends, namely 5OH/5OL (180g/kg) (male diet), 30H/70L (167g/kg) (both male and female diets) and 20H/80L (162g/kg) (female diet). Six pigs from each sex were allocated to each treatment. The EFG Pig Growth Model was used to determine the fat contents (lipid index) on the two feeds available and the three blends, to estimate the best times to sample pigs. It was estimated that phase 1 would terminate at 63 d, phase 2 at 70 d and phase 3 at 77 d of age. At the end of each phase two pigs from each sex and treatment were slaughtered. The lipid contents differed significantly between treatments at the end of phase 2 for the male pigs, with the highest being measured in pigs fed L (108g/kg), followed in order by those fed 70L/30H (86g/kg), those fed 5OL/5OH (74g/kg), and those fed H (68g/kg) with the least lipid content. The lipid contents of the female pigs were highly significantly different at the end of phase 3, with the highest being measured in pigs fed L (147g/kg), followed in order by those fed 80L/20H (124g/kg), those fed 70L/3OH (116g/kg) and the least lipid content from those fed H (115g/kg). As estimated by the EFG Pig Growth Model, the male and female pigs fed L treatment had the highest lipid content and those fed H treatment, achieving their target rate of lipid deposition, with the lowest lipid content. This study indicates that the response in protein gain and in efficiency of utilization of protein of pigs to a given feed is dependent on the amount and quality of the feed given to the animals previously. Also, the maximum rate of lipid deposition can be achieved by monitoring the changes in lipid deposition over a period of time, which enables an enhanced understanding of the theory of food intake regulation in a growing pig. As a result, accurate changes can be made when designing a phase-feeding program for growing pigs.<br>Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2005.

Purpose: To examine the variables that influence lipid deposition on conventional and silicone hydrogel contact lens materials and to build a physiologically relevant in vitro model of lipid deposition on contact lenses. Methods: Lipid deposition on contact lens materials can lead to discomfort and vision difficulty for lens wearers. Using a variety of radiochemical experiments and two model lipids (cholesterol and phosphatidylcholine), a number of clinically significant parameters that may influence lipid deposition were examined. • The optimization and characterization of a novel artificial tear solution (ATS) was examined (Chapter 3) • Optimization of an extraction system to remove deposited cholesterol and phosphatidylcholine from various contact lens materials (Chapter 4) • The influence of different tear film components on lipid deposition was researched (Chapter 5) • The efficiency of hydrogen peroxide disinfecting solutions to remove deposited lipid from contact lenses was investigated (Chapter 6) • The effect of intermittent air exposure on lipid deposition was examined through the use of a custom built “model blink cell” (Chapter 7) Results: A novel complex ATS designed for in-vial incubations of contact lens materials was developed. This solution was stable and did not adversely affect the physical parameters of the contact lenses incubated within it. An efficient extraction protocol for deposited cholesterol and phosphatidylcholine was optimized based on chloroform and methanol with the addition of water and acetic acid for phosphatidylcholine extraction. Overall, cholesterol and phosphatidylcholine deposition is cumulative over time and found to deposit in greater masses on silicone-containing hydrogels. Cholesterol and phosphatidylcholine deposition is influenced by the composition of the incubation medium and air exposure which occurs during the inter-blink period. Hydrogen peroxide disinfecting solutions were able to remove only marginal amounts of lipid from the contact lenses, with the surfactant containing solution removing more. Conclusion: This thesis has provided hitherto unavailable information on the way in which lipid interacts with conventional and silicone hydrogel contact lens materials and the in vitro model built here can be utilized in various ways in the future to assess other aspects and variables of lipid and protein deposition on a variety of biomaterials.

Dissertação de Mestrado, Ciências Biomédicas, Departamento de Ciências Biomédicas e Medicina, Universidade do Algarve, 2015<br>A malária é uma doença tropical causada por picada de mosquitos do género Anopheles gambiae infetados por parasitas do género Plasmodium. A malária consiste é prioridades na saúde pública internacional, e graças às metodologias utilizadas para o combate à infeção, controlo da doença e da transmissão, tem-se observado uma redução da taxa de mortalidade pela malária. O relatório anual “Malária Report 2015” previu uma redução da taxa de mortalidade em crianças de 5 anos de idade na ordem dos 61% globalmente e 67% na região africana da OMS. No entanto, ainda existe uma percentagem significativa da população em risco de ser infetada. O presente estudo vem no seguimento de trabalhos anteriores do grupo, sobre o recetor GPCR da hormona da paratiroide humana (PTH) no mosquito e visa analisar o efeito da PTH na oogénese/vitelogénese de mosquitos Anopheles gambiae. A deposição de lípidos e o crescimento folicular em mosquitos alimentados e injetados com PTH comparativamente com mosquitos alimentados com sangue, glucose e injetados com solução salina em diferentes pontos temporais (3, 6, 18, 24 horas pós-alimentação/pós-injeção) foram analisados. A comparação entre os grupos mostrou que o PTH possui um efeito similar à refeição sanguínea nas primeiras horas analisadas, sendo assim um fator iniciador da oogénese/vitelogénese em mosquitos A. gambiae. Esses resultados em conjunto com o aumento da expressão de genes associados à oogénese/ vitelogénese em mosquitos injetados com PTH às 6h pós-injeção semelhante ao observado nos mosquitos alimentados com sangue, indicam que o PTH é um fator sanguíneo essencial na regulação da oogénese e reprodução em mosquitos A. gambiae.<br>Malaria is a tropical disease caused by the bite of Anopheles gambiae mosquitoes infected by Plasmodium parasite. Malaria is an international health priority and thanks to the methodologies used to fight infection and control the disease and transmission has led to malaria mortality reduction worldwide. The annual “Malaria Report 2015”, estimated a reduction of 61% global and 67% in the African region of WHO mortality rate in children under 5 years old. However, there´s still a significant percentage of population at risk of being infected. This study follows previous work of the group on GPCR receptor of human parathyroid hormone (PTH) in the mosquito and aims to analyze the effect of PTH on oogenesis/viletogenesis of A. gambiae mosquitoes. Lipid deposition and follicular growth in ovaries was analyzed on mosquitoes fed or injected with PTH and compared to mosquitoes fed on blood, glucose or injected with saline solution at different time intervals (3, 6, 18, 24 hours post-feed or post-injection). The comparison showed that PTH treatment has similar effects as blood meal at the early hours of oogenesis and thus is an initiator factor of oogenesis/vitelogenesis in A. gambiae. These results together with increased expression of genes associated with oogenesis/ vitelogenensis in mosquitoes injected with PTH at 6h post-injection similar to what is observed in blood fed mosquitoes indicates that PTH is a key factor in the regulation of oogenesis and reproduction of A. gambiae mosquitoes.

Purpose To study the impact of lactoferrin and lipids on the kinetic deposition and denaturation of lysozyme on contact lens materials. Methods The contact lenses investigated in this thesis included two silicone hydrogel lenses [AIR OPTIX AQUA; lotrafilcon B and ACUVUE OASYS; senofilcon A] and two conventional hydrogel lenses [ACUVUE 2; etafilcon A and PROCLEAR; omafilcon A]. All lenses were incubated in four solutions: a complex artificial tear solution (ATS); an ATS without lactoferrin; an ATS without lipids; and an ATS without lactoferrin and lipids. Following various time points, all lenses were prepared for lysozyme analysis using the methods below: • To quantify the kinetic uptake of lysozyme to different contact lens materials, I125-radiolabelled lysozyme was added to each incubation solution. Total lysozyme deposition was quantified using a gamma counter. • To study the activity of lysozyme deposited to contact lenses, a fluorescence-based lysozyme activity assay was compared to a turbidity assay. Potential interactions with lens materials and extraction solvents were evaluated. • To investigate the kinetic denaturation of lysozyme deposited to different contact lens materials, the fluorescence-based activity assay and the enzyme-linked immunosorbent assay were used. Results The presence of lactoferrin and lipids decreased lysozyme uptake to lotrafilcon B. Lysozyme deposition on senofilcon A was greater in the absence of lipids after day 21, however the opposite was seen with etafilcon A, where lysozyme uptake was lower without lipids in the ATS. Lactoferrin and/or lipids had no effect on lysozyme adsorption to omafilcon A. The fluorescence-based lysozyme activity assay demonstrated high sensitivity and a wide linear range of detection, which covers the amount of lysozyme typically extracted from contact lenses. Using this assay, lysozyme activity on both silicone hydrogel materials was lower in the presence of lipids in the ATS. In addition, lactoferrin had a protective effect on lysozyme activity for lysozyme sorbed to senofilcon A. Moreover, the presence of lactoferrin and/or lipids did not exhibit any effect on lysozyme denaturation with conventional hydrogel lenses. Conclusions The presence of lactoferrin and lipids in an artificial tear solution impacted lysozyme deposition and denaturation of lysozyme on various contact lenses. It is important for in vitro studies, when developing tear film models, to consider the effects of tear film components when investigating protein deposition and denaturation on contact lenses.