A colina é um nutriente essencial nas dietas de frangos de corte. Os valores de exigências nutricionais são variáveis e foram estabelecidos há muitos anos. Assim, o objetivou-se com este trabalho reavaliar as respostas de frangos de corte de alto potencial genético de 1 a 7, 1 a 14 e 1 a 21 dias de idade como também modelar as respostas por diferentes funções matemáticas. Foram conduzidos dois experimentos sob dois níveis de metionina na dieta, tendo como base o método dose-resposta. Para os ensaios, foram utilizados 2.160 pintos de corte machos da linhagem Cobb 500 (1.080 em cada experimento), distribuídos em um delineamento inteiramente casualizado, com seis tratamentos, seis repetições e 30 aves por unidade experimental. Os tratamentos consistiram em rações com níveis de 390, 715, 1.040, 1.365, 1.690 e 2.015 mg/kg de colina. As rações experimentais foram formuladas utilizando-se a técnica da suplementação. Foi formulada uma ração basal à base de milho, farelo de soja, concentrado proteico de soja, açúcar e amido contendo 390 mg/kg de colina total e 0,596% de metionina digestível. O cloreto de colina (62,5%) comercial foi suplementado para obter os demais níveis. O segundo experimento consistiu nos mesmos tratamentos do primeiro, porém com atendimento de 0,440% da metionina digestível. As variáveis mensuradas em ambos os ensaios foram: consumo de ração, consumo de colina, conversão alimentar e ganho de peso. Para modelar as respostas considerou-se o consumo de colina como variável independente e ganho de peso como variável dependente. As respostas foram modeladas por cinco modelos matemáticos: broken line, broken line com ascendência quadrática, cinética de saturação, logístico e monomolecular e o melhor modelo foi selecionado pelo critério de Akaike. As análises estatísticas foram realizadas com auxílio do programa computacional SAS® utilizando o procedimento PROC GLM para análise das pressuposições e análise de variância e PROC NLIN para o ajuste dos modelos. Os modelos que melhor se ajustaram foram: Broken line com ascendência quadrática (1,26 mg/g de GP ensaio 1) e Logístico (1,26 mg/g de GP ensaio 2) para o período de 1 a 7 dias. No período de 1 a 14 dias os modelos selecionados para o experimento com metionina normal e reduzida foram Logístico (1,16 mg/g de GP) e Broken line com ascendência quadrática (1,28 mg/g de GP), respectivamente. Já para o período de 1 a 21 foram o cinética de saturação, estimando uma exigência de 1,35 mg/g de GP para o experimento com metionina normal, e Broken line com ascendência quadrática estimando uma exigência de 1,21 mg de colina/g de GP para o experimento com metionina reduzida. / Choline is an essential nutrient in the diets of chicks. Supplementation levels in feeds is variable and requirements have been established many years ago. Thus, the objective of this study was to reassess the responses of high genetic potential chicks from 1-7, 1-14 and 1 to 21 days as well as modeling the responses of different mathematical functions. Two trials were conducted using two dietary levels of methionine, based on the dose-response method. For the trials were used 2,160 Cobb 500 male broiler chicks (1,080 birds in each experiment), distributed in a completely randomized design with six treatments and six replicates and 30 birds per experimental unit. The treatments consisted of diets with levels of 390, 715, 1,040, 1,365, 1,690 and 2,015 mg/kg of choline. The diets were formulated using the supplementation method. The basal diet was formulated based on corn, soybean meal, soy protein concentrate, sugar and starch, and contained 390 mg/kg of choline and 0.596% of digestible methionine. Commercial choline chloride (62.5%) was supplemented to obtain the other levels. The second trial consisted of the same treatments of the first, but with 0.440% of digestible methionine. The variables measured in both trials were: feed intake (FI), intake of choline (IC), feed conversion (FC) and weight gain (WG). To model the responses, the variables used were the intake of choline as an independent variable and weight gain as the dependent variable. The responses were modeled by five mathematical models: broken line (ascending linear and quadratic segments), saturation kinetic, 4-parameter logistics and monomolecular models and the best model was selected by Akaike information criterion. Statistical analyzes were performed using the computer program SAS® using PROC GLM for analysis of the assumptions and analysis of variance and PROC NLIN to fit the models. The models that best fit were: broken line quadratic segments (1.26 mg/g of WG - trial 1) and Logistics (1.26 mg/g of WG - trial 2) for the period 1-7 days. In the period 1-14 days, the models selected for the experiment with normal and deficient methionine were Logistic (1.16 mg/g WG) and broken line quadratic segments (1.28 mg/g WG), respectively. For the period 1-21days, the models were the saturation kinetics, estimating a requirement of 1.35 mg/g of WG for the experiment with normal methionine, and broken line quadratic segments estimating a requirement of 1.21 mg choline/g of WG for the experiment with deficient methionine.

Actively proliferating cells constantly monitor and re-adjust their metabolic pathways to ensure the replenishment of phospholipids necessary for membrane biogenesis and intracellular trafficking. In Saccharomyces cerevisiae, multiple studies have suggested that lysine acetylation has a role in coordinating phospholipid metabolism, yet its contribution towards phospholipid homeostasis remains uncharacterized. In this study we undertook a genetic screen to explore the connection between lysine acetylation and phospholipid homeostasis. We found that mutants of the lysine acetyltransferase complex, NuA4, shared a negative genetic interaction with a mutant of Sec14, a lipid-binding protein that regulates Golgi phospholipid composition. Through transcriptome, genetic, cell biology, and chemical analysis, we discovered that the growth defects between NuA4 and Sec14 mutants is likely derived from impaired fatty acid biosynthesis suggesting a role for NuA4 as a positive regulator of fatty acid biosynthesis. Secondly, we discovered that acetylation on the conserved lysine residue K109 inhibits the localization and function of the Oxysterol-Binding Protein Osh4- a lipid-binding protein that antagonizes the function of Sec14 at the Golgi. Furthermore, regulation of Oxysterol-Binding Proteins by acetylation may be a conserved mechanism as we found that Osh1, a homologue of Osh4, was also acetylated on the equivalent lysine residue. Altogether, we have demonstrated that lysine acetylation can target multiple different phospholipid metabolic pathways which implies that it has a very important role for the regulation of phospholipid homeostasis.

O objetivo desse estudo foi avaliar o efeito da suplementação de níveis crescentes de colina e de aminoácidos sulfurados totais (AST) digestíveis em uma dieta de milho e proteína isolada de soja, sobre o desempenho produtivo, bem como a ocorrência de deformidades e desvios nas patas e fígado gorduroso de frangos de corte. Foram alojados 525 frangos de corte, machos Cobb 500, de um dia de idade, em 75 gaiolas experimentais. As aves foram distribuídas em um delineamento inteiramente casualizado com 15 tratamentos, 5 repetições e 7 aves por unidade experimental. Foi utilizada uma dieta basal semipurificada com 74% de milho (736 ppm de colina) e esta foi suplementada utilizando um arranjo fatorial 3 x 5 com 3 níveis de AST digestíveis em relação à lisina digestível (70, 75 e 80%) e 5 níveis de suplementação de colina (0, 700, 1.400, 2.100 e 2.800 ppm). Foi utilizado um programa alimentar de 2 fases: pré-inicial (1 a 7 d) e inicial (8 a 21 d). Ganho de peso (GP), consumo de ração e conversão alimentar (CA) foram avaliados aos 7, 14 e 21 d. Aos 21 d, as aves foram avaliadas para perose, valgus, varus e tibia rotada na articulação tibio matatarsal, os fígados foram avaliados macroscopicamente (coloração, tamanho e consistência) e quanto ao seu teor de extrato etéreo. Os dados foram submetidos à análise de variância e as médias foram comparadas pelo teste de Tukey. Regressões lineares e quadráticas foram estimadas para as variáveis de desempenho produtivo e a resposta máximada de suplementação de colina foi estimada. Não houve interação entre AST digestíveis e colina, também não houve diferença entre os níveis de AST digestíveis (P>0,05). O GP dos frangos alimentados com níveis crescentes de colina aumentou quadraticamente (P<0,05) de 1 a 7 d, 8 a 14 d, 1 a 14 d, 15 a 21 d e 1 a 21 d e a CA diminuiu quadraticamente (P<0,05) 1 a 14 d e 1 a 21 d. No período de 1 a 7 d, 8 a 14 d e 15 a 21d foram estimadas exigências de 2.700, 2.907 e 3.105 ppm para GP. De 1 a 14 d e 1 a 21 d, as exigências foram de 2.875 ppm e 2.925 ppm para GP, e 2.938 ppm e 2.849 ppm para CA. Os tratamentos que não receberam suplementação de colina apresentaram maior ocorrência de varus e tibia rotada (P<0,05), quando comparados aos outros níveis de colina, não houve diferença entre os níveis de colina para valgus. Os níveis de colina em que houve o melhor GP e CA para frangos foram determinados como 2.925 ppm e 2.849 ppm para as fases iniciais. Considerando-se uma ração de milho e farelo de soja (1.500 ppm de colina), 1.425 e 1.349 ppm de suplementação de colina são apropriados para melhorar a performance de frangos de corte de 1 a 21 d. Esses valores são superiores às recomendações prévias para as fases iniciais (500 ppm). / The objective of this study was to evaluate growth performance, the occurrence of leg deformity and deviations and fatty liver of broilers fed a corn and soy protein isolate diet supplemented with increasing levels of choline and digestible total sulfur amino acid (TSAA). A total of 525 one-day-old Cobb 500 chicks were distributed in a completely randomized design in 75 battery cages, 15 treatments, and 7 birds per cage. A 74% corn semi-purified basal diet (736 ppm of choline) was supplemented using a 3 x 5 factorial arrangement with 3 levels of digestible TSAA ratio to digestible lysine (70, 75 and 80%) and 5 levels of choline supplementation (0; 700; 1,400; 2,100, and 2,800 ppm). A 2-phases feeding program was used: pre-initial (1 to 7 d) and initial (8 to 21 d). Body weight gain (BWG), feed intake and feed conversion ratio (FCR) were evaluated at 7, 14 and 21 d. At 21 d all birds were evaluated for perosis, valgus, varus and rotated tibia in tibiometatarsal joint, livers were evaluated macroscopically (color, size, and consistency) and for fat content. Data were submitted to analysis of variance and means were compared by the Tukey test. Performance data were fitted to linear and quadratic polynomial regressions and the maximum response of choline supplementation was estimated. No interactions between digestible TSAA and choline were observed, also no differences among digestible TSAA levels (P>0.05). The BWG of broilers fed diets with increasing levels of choline increased quadratically (P<0.05) from 1 to 7 d, 8 to 14 d, 1 to 14 d, 15 to 21 d, and 1 to 21 d, also FCR decreased quadratically (P<0.05) from 1 to 14 d and 1 to 21 d. From 1 to 7 d, 8 to 14 d, and 15 to 21d quadratic regression estimated requirements as 2,700, 2,907, and 3,105 ppm for BWG. From 1 to 14 d and 1 to 21 d, quadratic regression estimates were 2,875 ppm and 2,925 ppm for BWG, and 2,938 ppm and 2,849 ppm for FCR. Treatments with no supplementation of choline had higher occurrence of varus and rotated tibia (P<0.05) compared to the other levels of choline. There was no difference for valgus deviation. Choline level that provided better BWG and FCR responses were determined as 2,925 and 2,849 ppm for starter phases, respectively. Considering a corn-soybean meal common diet (1,500 ppm of choline), 1,425 and 1,349 ppm of choline inclusions are appropriate to improve BWG and FCR response for broilers from 1 to 21 d, which are above previous recommendation for starter phases (500 ppm of choline).

O objetivo desta pesquisa foi desenvolver, validar e comparar métodos analíticos para separação e quantificação de citrato de colina e acetilmetionina em formulações injetáveis por cromatografia líquida de alta eficiência (CLAE) e eletroforese capilar (EC). O método por CLAE, com o qual foi possível quantificar e separar simultaneamente, o citrato de colina e a acetilmetionina, foi realizado empregando-se uma coluna cromatográfica C18, 250 x 4,6 mm, 5&#181;m, Shim-Pack® VP-ODS e fase móvel constituída por tampão fosfato de potássio 25 mM pH 5,7: acetonitrila: metanol (88:10:2 v/v/v). O método por EC foi validado utilizando-se como eletrólito, tampão de tetraborato de sódio 20 mM a pH 9,2 e capilar de sílica fundida de 40,2 cm, sendo 30 cm efetivos, com 75 µm de diâmetro interno. O método por CLAE apresentou um coeficiente de correlação (r) de 0,9996 para o citrato de colina e 0,9998 para a acetilmetionina. No método por EC, o coeficiente de correlação (r) encontrado foi de 0,9996 para a acetilmetionina. Os métodos podem ser considerados eficientes e confiáveis para serem empregados em análises de rotina de controle de qualidade de soluções injetáveis contendo a associação dos dois fármacos selecionados para o estudo. / The objective of this research was to develop, to validate and to compare two analytical methods for separation and quantification of choline citrate and acetylmethionine in injectable formulations by high performance liquid chromatography (HPLC) and capillary electrophoresis (CE). The HPLC method which enables the separation and simultaneous quantitative determination of choline citrate and acetylmethionine was performed using a C18, 250 x 4.6 mm, 5&#181;m-Shim-Pack®VP-ODS column and a mobile phase constituted of buffer 25 mM potassium phosphate, pH 5.7: acetonitrile: methanol (88:10:2 v/v/v). The CE method was validated using a solution of 20 mM sodium tetraborate buffer pH 9.2 as the electrolyte and a fused silica capillary of 40.2 cm, with 30 cm effective, and 75 mm of diameter. The HPLC method showed a correlation coefficient (r) of 0.9996 for choline citrate and 0.9998 for acetylmethionine. For CE method the correlation coefficient (r) was found to be 0.9996 for acetylmethionine. The methods showed to be efficient and reliable methods, and can be used in routine analysis for quality control of injectable solutions containing the association of the two compounds selected to be studied in this research.

O objetivo desta pesquisa foi desenvolver, validar e comparar métodos analíticos para separação e quantificação de citrato de colina e acetilmetionina em formulações injetáveis por cromatografia líquida de alta eficiência (CLAE) e eletroforese capilar (EC). O método por CLAE, com o qual foi possível quantificar e separar simultaneamente, o citrato de colina e a acetilmetionina, foi realizado empregando-se uma coluna cromatográfica C18, 250 x 4,6 mm, 5&#181;m, Shim-Pack® VP-ODS e fase móvel constituída por tampão fosfato de potássio 25 mM pH 5,7: acetonitrila: metanol (88:10:2 v/v/v). O método por EC foi validado utilizando-se como eletrólito, tampão de tetraborato de sódio 20 mM a pH 9,2 e capilar de sílica fundida de 40,2 cm, sendo 30 cm efetivos, com 75 µm de diâmetro interno. O método por CLAE apresentou um coeficiente de correlação (r) de 0,9996 para o citrato de colina e 0,9998 para a acetilmetionina. No método por EC, o coeficiente de correlação (r) encontrado foi de 0,9996 para a acetilmetionina. Os métodos podem ser considerados eficientes e confiáveis para serem empregados em análises de rotina de controle de qualidade de soluções injetáveis contendo a associação dos dois fármacos selecionados para o estudo. / The objective of this research was to develop, to validate and to compare two analytical methods for separation and quantification of choline citrate and acetylmethionine in injectable formulations by high performance liquid chromatography (HPLC) and capillary electrophoresis (CE). The HPLC method which enables the separation and simultaneous quantitative determination of choline citrate and acetylmethionine was performed using a C18, 250 x 4.6 mm, 5&#181;m-Shim-Pack®VP-ODS column and a mobile phase constituted of buffer 25 mM potassium phosphate, pH 5.7: acetonitrile: methanol (88:10:2 v/v/v). The CE method was validated using a solution of 20 mM sodium tetraborate buffer pH 9.2 as the electrolyte and a fused silica capillary of 40.2 cm, with 30 cm effective, and 75 mm of diameter. The HPLC method showed a correlation coefficient (r) of 0.9996 for choline citrate and 0.9998 for acetylmethionine. For CE method the correlation coefficient (r) was found to be 0.9996 for acetylmethionine. The methods showed to be efficient and reliable methods, and can be used in routine analysis for quality control of injectable solutions containing the association of the two compounds selected to be studied in this research.

The disturbances and abnormalities occurring in the components of the Acetylcholine (ACh) neurocycle are considered one of the main features of cholinergic sicknesses like Parkinson’s and Alzheimer’s diseases. A fundamental understanding of the ACh neurocycle is therefore very critical in order to design drugs that keep the ACh concentrations in the normal physiological range. In this dissertation, a novel two-enzyme-two-compartment model is proposed in order to explore the bifurcation, dynamics, and chaotic characteristics of the ACh neurocycle. The model takes into consideration the physiological events of the choline uptake into the presynaptic neuron and the ACh release in the postsynaptic neuron. In order to approach more realistic behavior, two complete kinetic mechanisms for enzymatic processes pH-dependent are built: the first mechanism is for the hydrolysis reaction catalyzed by the acetylcholinesterase (AChE) and the other is for the synthesis reaction catalyzed by the cholineacetyltransferase (ChAT). The effects of hydrogen ion feed concentrations, AChE activity, ChAT activity, feed ACh concentrations, feed choline concentrations, and feed acetate concentrations as bifurcation parameters, on the system performance are studied. It was found that hydrogen ions play an important role, where they create potential differences through the plasma membranes. The concentrations of ACh, choline and acetate in compartments 1 and 2 are affected by the activity of AChE through a certain range of their concentrations, where the activity of AChE is inhibited completely after reaching certain values. A detailed bifurcation analysis over a wide range of parameters is carried out in order to uncover some important features of the system, such as hysteresis, multiplicity, Hopf bifurcation, period doubling, chaotic characteristics, and other complex dynamics. The effects of the feed choline concentrations and the feed acetate concentrations as bifurcation parameters are studied in this dissertation. It is found that the feed choline concentrations play an important role and have a direct effect on the ACh neurocycle through a certain important range of the parameters. However, the feed acetate concentrations have less effect. It is concluded from the results that the feed choline is a more important factor than the feed acetate in ACh processes. The effects of ChAT activity and the choline recycle ratio as bifurcation parameters, on the system performance are investigated. It was found that as the ChAT activity increases, ACh concentrations in compartments 1 and 2 increase continuously. The effect of the choline recycle ratio shows that choline reuptake plays a very critical role in the synthesis of ACh in compartment 1, where it supplies the choline as a substrate for the synthesis reaction by ChAT. The concentrations of ACh, choline and acetate in compartments 1 and 2 are affected by the choline recycle ratio through a certain range of the choline recycle ratio; then, they become constant as the choline recycle ratio increases further. It is concluded from our results that choline uptake is the rate limiting step in the ACh processes in both compartments in comparison to ChAT activity. Based on partial dissociation of the acetic acid in compartments 1, and 2 of the ACh cholinergic system, the two-parameter continuation technique has been applied to investigate the pH range to be closer to physiological ranges of pH values. In addition, static/dynamic solutions of the ACh cholinergic neurocycle system based on feed choline concentration as the main bifurcation parameter in both compartments have been investigated. The findings of the above studies are related to the real phenomena occurring in the neurons, like periodic stimulation of neural cells and non-regular functioning of ACh receptors. It was found that ACh, choline, acetate, and pH exist inside the physiological range associated with taking into consideration the partial dissociation of the acetic acid. The disturbances and irregularities (chaotic attractors) occurring in the ACh cholinergic system may be good indications of cholinergic diseases such as Alzheimer’s and Parkinson’s diseases. The results have been compared to the results of physiological experiments and other published models. As there is strong evidence that cholinergic brain diseases like Alzheimer’s disease and Parkinson’s disease are related to the concentration of ACh, the present findings are useful for uncovering some of the characteristics of these diseases and encouraging more physiological research.

The disturbances and abnormalities occurring in the components of the Acetylcholine (ACh) neurocycle are considered one of the main features of cholinergic sicknesses like Parkinson’s and Alzheimer’s diseases. A fundamental understanding of the ACh neurocycle is therefore very critical in order to design drugs that keep the ACh concentrations in the normal physiological range. In this dissertation, a novel two-enzyme-two-compartment model is proposed in order to explore the bifurcation, dynamics, and chaotic characteristics of the ACh neurocycle. The model takes into consideration the physiological events of the choline uptake into the presynaptic neuron and the ACh release in the postsynaptic neuron. In order to approach more realistic behavior, two complete kinetic mechanisms for enzymatic processes pH-dependent are built: the first mechanism is for the hydrolysis reaction catalyzed by the acetylcholinesterase (AChE) and the other is for the synthesis reaction catalyzed by the cholineacetyltransferase (ChAT). The effects of hydrogen ion feed concentrations, AChE activity, ChAT activity, feed ACh concentrations, feed choline concentrations, and feed acetate concentrations as bifurcation parameters, on the system performance are studied. It was found that hydrogen ions play an important role, where they create potential differences through the plasma membranes. The concentrations of ACh, choline and acetate in compartments 1 and 2 are affected by the activity of AChE through a certain range of their concentrations, where the activity of AChE is inhibited completely after reaching certain values. A detailed bifurcation analysis over a wide range of parameters is carried out in order to uncover some important features of the system, such as hysteresis, multiplicity, Hopf bifurcation, period doubling, chaotic characteristics, and other complex dynamics. The effects of the feed choline concentrations and the feed acetate concentrations as bifurcation parameters are studied in this dissertation. It is found that the feed choline concentrations play an important role and have a direct effect on the ACh neurocycle through a certain important range of the parameters. However, the feed acetate concentrations have less effect. It is concluded from the results that the feed choline is a more important factor than the feed acetate in ACh processes. The effects of ChAT activity and the choline recycle ratio as bifurcation parameters, on the system performance are investigated. It was found that as the ChAT activity increases, ACh concentrations in compartments 1 and 2 increase continuously. The effect of the choline recycle ratio shows that choline reuptake plays a very critical role in the synthesis of ACh in compartment 1, where it supplies the choline as a substrate for the synthesis reaction by ChAT. The concentrations of ACh, choline and acetate in compartments 1 and 2 are affected by the choline recycle ratio through a certain range of the choline recycle ratio; then, they become constant as the choline recycle ratio increases further. It is concluded from our results that choline uptake is the rate limiting step in the ACh processes in both compartments in comparison to ChAT activity. Based on partial dissociation of the acetic acid in compartments 1, and 2 of the ACh cholinergic system, the two-parameter continuation technique has been applied to investigate the pH range to be closer to physiological ranges of pH values. In addition, static/dynamic solutions of the ACh cholinergic neurocycle system based on feed choline concentration as the main bifurcation parameter in both compartments have been investigated. The findings of the above studies are related to the real phenomena occurring in the neurons, like periodic stimulation of neural cells and non-regular functioning of ACh receptors. It was found that ACh, choline, acetate, and pH exist inside the physiological range associated with taking into consideration the partial dissociation of the acetic acid. The disturbances and irregularities (chaotic attractors) occurring in the ACh cholinergic system may be good indications of cholinergic diseases such as Alzheimer’s and Parkinson’s diseases. The results have been compared to the results of physiological experiments and other published models. As there is strong evidence that cholinergic brain diseases like Alzheimer’s disease and Parkinson’s disease are related to the concentration of ACh, the present findings are useful for uncovering some of the characteristics of these diseases and encouraging more physiological research.

ABSTRACT BIOACTIVE SURFACE DESIGN BASED ON CONDUCTING POLYMERS AND APPLICATIONS TO BIOSENSORS Ekiz, Fulya M. Sc., Department of Biotechnology Supervisor: Prof. Dr. Levent Toppare Co-Supervisor: Prof. Dr. Suna Timur June 2012, 88 pages An underlying idea of joining the recognition features of biological macromolecules to the sensitivity of electrochemical devices has brought the concept of biosensors as remarkable analytical tools for monitoring desired analytes in different technological areas. Over other methods, biosensors have some advantages including high selectivity, sensitivity, simplicity and this leads to solutions for some problems met in the measurement of some analytes. In this context, conducting polymers are excellent alternatives with their biocompatibility and ease of applicability for an efficient immobilization of biomolecules in preparing biosensors. Using several materials and arranging the surface properties of the electrodes, more efficient and seminal designs can be achieved. In this thesis, it is aimed to create new direct biosensors systems for the detection of several analytes such as glucose and pesticides thought to be harmful to the environment. Recently synthesized conducting polymers (polyTBT) / (poly(2-dodecyl-4,7-di(thiophen-2-yl)-2H-benzo[ d][1,2,3]triazole) and (poly(TBT 6 -NH2 ) / poly(6-(4,7-di(thiophen-2-yl)-2H-benzo[d][1,2,3]triazol-2-yl)hexan-1-amine) were utilized as a matrices for biomolecule immobilization. After successful electrochemical deposition the polymers on the graphite electrode surfaces, immobilization of glucose oxidase (GOx) and choline oxidase (ChO) were carried out. Amperometric measurements were recorded by monitoring oxygen consumption in the presence of substrates at -0.7 V. The optimized biosensors showed a very good linearity with rapid response times and low detection limits (LOD) to glucose and choline. Also, kinetic parameters, operational and storage stabilities were determined. Finally, designed biosensor systems were applied for glucose and pesticide detection in different media.

This study characterizes B vitamin supplement use prior to and during pregnancy, changes in dietary one-carbon nutrient intakes (folate, vitamin B12, vitamin B6, choline, betaine and methionine) and most significant dietary sources. In Canadian women (Toronto, Ontario) supplemental (n=364) and dietary intakes (using a food frequency questionnaire) (n=290) were assessed during early and late pregnancy. Majority reported using a B vitamin-containing supplement prior (60%) to and during early (93%) and late (89%) pregnancy. Median supplemental intakes of folic acid, B12 and B6 were 1000 µg/d, 2.6 µg/d and 1.9 mg/d, respectively. Dietary one-carbon nutrient intakes did not change appreciably between early and late pregnancy. Most significant sources of folate and B6 were fruits and vegetables, of folic acid were cereals and grains and of B12 were dairy and egg products. Overall, this study provides novel information about one-carbon nutrient intakes in pregnancy which are crucial in maternal and child health.

This study characterizes B vitamin supplement use prior to and during pregnancy, changes in dietary one-carbon nutrient intakes (folate, vitamin B12, vitamin B6, choline, betaine and methionine) and most significant dietary sources. In Canadian women (Toronto, Ontario) supplemental (n=364) and dietary intakes (using a food frequency questionnaire) (n=290) were assessed during early and late pregnancy. Majority reported using a B vitamin-containing supplement prior (60%) to and during early (93%) and late (89%) pregnancy. Median supplemental intakes of folic acid, B12 and B6 were 1000 µg/d, 2.6 µg/d and 1.9 mg/d, respectively. Dietary one-carbon nutrient intakes did not change appreciably between early and late pregnancy. Most significant sources of folate and B6 were fruits and vegetables, of folic acid were cereals and grains and of B12 were dairy and egg products. Overall, this study provides novel information about one-carbon nutrient intakes in pregnancy which are crucial in maternal and child health.