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.

No description available.

Pyrosequencing is a new DNA sequencing method relying on thesequencing-by-synthesis principle and bioluminometric detectionof nucleotide incorporation events. The objective of thisthesis was improvement of the Pyrosequencing method byincreasing the thermal stability of firefly luciferase, and byintroducing an alternative DNA polymerase and a new nucleotideanalog. Furthermore, the development of a new bioluminescentassay is described for the detection of inorganicpyrophosphatase activity. The wild-type North American firefly(Photinus pyralis)luciferase is a heat-sensitiveenzyme, the catalytic activity of which is rapidly lost attemperatures over 30°C. Two strategies for increasing thethermostability of the enzyme are presented and discussed. Inthe first strategy, the solution thermodynamics of the systemis affected by osmolytes in such a way that heat-mediatedinactivation of the enzyme is prevented. In the secondstrategy, the enzyme is thermostabilized by mutagenesis. Bothstabilizing strategies can be utilized to allow bioluminometricassays to be performed at higher temperatures. For instance,both DNA polymerase and ATP sulfurylase activity could beanalyzed at 37°C. The osmolyte strategy was successfully employed forincreasing the reaction temperature for the Pyrosequencingmethod. By increasing the reaction temperature to 37°Cunspecific signals from primer-dimers and 3’-end loopswere reduced. Furthermore, sequencing of a challenging templateat 37°C, which previously yielded poor, non-interpretablesequence signals at lower temperatures was now possible. Introduction of a new adenosine nucleotide analog,7-deaza-2’-deoxyadenosine-5’-triphosphate (c7dATP) reduced the inhibitory effect on apyraseobserved with the currently used analog,2’-deoxyadenosine-5’-O-(1-thiotriphosphate)(dATPαS). Sequencing of homopolymeric T-regions has previously beendifficult with the exonuclease-deficient form of the DNApolymerase I large (Klenow) fragment. By using the DNApolymerase from bacteriophage T7, known as Sequenase, templateswith homopolymeric T-regions were successfully sequenced.Furthermore, it was found that the strand displacement activityfor both polymerases was strongly assisted if the displacedstrand had a 5’-overhang. In contrast, the stranddisplacement activity for both polymerases was inhibitedwithout an overhang, resulting in reduced sequencingperformance in double stranded regions. A firefly bioluminescent assay for the real-time detectionof inorganic pyrophosphatase in the hydrolytic direction wasalso developed. The assay is versatile and has a linearresponse in the range between 8 and 500 mU. Key words:bioluminescence, osmolytes, glycine betaine,thermostability, firefly luciferase, inorganic pyrophosphatase,inorganic pyrophosphate, Pyrosequencing technology, secondaryDNA-structures, Sequenase, Klenow-polymerase, reaction rates,temperature, c7dATP, dATPαS. / <p>QCR 20161027</p>

A betaína é um trimetil derivado do aminoácido glicina. Os seus principais efeitos fisiológicos são atuar como um osmólito e como doador de radicais metil. Especulase que a betaína possa contribuir para a síntese de creatina no músculo esquelético pelo fornecimento de grupos metil, resultante da conversão de betaína em dimetilglicina, para a remetilação de homocisteína em metionina. Os efeitos da suplementação de creatina sobre o desempenho são conhecidos e relacionam-se principalmente ao aumento na ressíntese de fosforilcreatina (PCR). Autores de estudos recentes têm atribuído seus resultados positivos em relação ao aumento de força muscular a um possível efeito da betaína sobre as concentrações de PCR. Essa variável, entretanto, não foi avaliada, de maneira que os mecanismos responsáveis pelo aumento de força advindo da suplementação de betaína ainda são inexplorados em humanos. Diante disso, este estudo teve como objetivo investigar os efeitos da suplementação de betaína, combinada ou não com a suplementação de creatina, sobre as concentrações intramusculares de PCR, e a produção de força e potência muscular em indivíduos não treinados em força. Além disso, as respostas fisiológicas e ergogênicas da suplementação de betaína e creatina foram comparadas e avaliados os possíveis efeitos aditivos desses suplementos. Foi conduzido um estudo duplo-cego, randomizado, controlado por placebo. Trinta e quatro sujeitos foram divididos em quatro grupos: Betaína (BET; 2 g/dia), Creatina (CR; 20 g/dia), Betaína + Creatina (BET + CR; 2 + 20 g/dia) e Placebo (PL). No período basal (PRÉ) e após 10 dias de suplementação (PÓS), os indivíduos submeteram-se a avaliações do consumo alimentar e da composição corporal, a testes de força e potência muscular e à quantificação intramuscular de PCR. Após a intervenção, as concentrações intramusculares de PCR foram maiores nos grupos CR e BET + CR, quando comparados ao grupo PL (p = 0,004 e p = 0,006, respectivamente). Não houve diferenças significativas entre os grupos BET e PL (p = 0,78) e CR e BET + CR (p = 0,99). Os grupos CR e BET + CR apresentaram maior produção de potência muscular no exercício de agachamento, quando comparados ao grupo PL (p = 0,003 e p = 0,041, respectivamente). Resultados similares foram encontrados para o exercício de supino. Os grupos CR e BET + CR também demonstraram aumento significativo de força muscular (teste de 1-RM) do teste PRÉ para o teste PÓS nos exercícios de supino e agachamento (CR: p = 0,027 e p 0,0001; BET + CR: p = 0,03 e p 0,0001 para membros superiores e inferiores, respectivamente). Não houve diferenças significativas para os testes de força e de potência muscular entre os grupos BET e PL e os grupos CR e BET + CR. Também não houve diferença significativa entre os grupos para a composição corporal. O consumo alimentar permaneceu inalterado ao longo do estudo. Os resultados permitem concluir que a suplementação de betaína, combinada ou não com a suplementação de creatina, não aumenta o conteúdo intramuscular de PCR e não afeta o desempenho de força e de potência muscular / Betaine is a trimethyl derivative of the amino acid glycine. The main physiological functions of betaine are to act as an organic osmolyte and as a donor of methyl radicals. It is speculated that betaine may contribute to the synthesis of creatine in skeletal muscle through the donation of a methyl group, resulting from the conversion of betaine to dimethylglycine, to homocysteine to form methionine. The effects of creatine supplementation on performance are well known and are related primarily to an increase in fosforilcreatina resynthesis (PCR). Authors of recent studies have attributed its positive results regarding the increase of muscle strength to a possible effect of betaine on the concentrations of PCR. However, this variable was not assessed, so that the mechanisms responsible for the increase in muscle strength coming from betaine supplementation in humans are still unexplored. In light of this, the aim of this study was to investigate the effect of betaine supplementation combined or not with creatine supplementation on muscle PCR content, muscle strength and power output in non-resistance trained subjects. Additionally, we compared the ergogenic and physiological responses to betaine versus creatine supplementation. Finally, we also tested the possible additive effects of creatine and betaine supplementation. A randomized, double-blind, placebo-controlled study was conducted. Thirty and four subjects were assigned into four groups: Betaine (BET; 2 g/day), Creatine (CR; 20 g/day), Betaine + Creatine (BET + CR; 2 + 20 g/day) or Placebo (PL). At baseline (PRE) and after 10 days of supplementation (POST) body composition, food intake, muscle strength and power and muscle PCR were assessed. The CR and BET + CR groups presented greater increase in muscle PCR content than PL (p = 0.004 and p = 0.006, respectively). PCR content was comparable between BET versus PL (p = 0.78) and CR versus BET + CR (p = 0.99). CR and BET + CR presented greater muscle power output than PL in the squat exercise following supplementation (p = 0.003 and p = 0.041, respectively). Similarly, bench press average power was significantly greater for the CR-supplemented groups. CR and BET + CR groups also showed significant pre- to post-test increase in 1-RM squat and bench press (CR: p = 0.027 and p 0.0001; BET + CR: p = 0.03 and p 0.0001 for upper- and lower-body assessments, respectively). No significant differences for 1-RM strength and power were observed between BET versus PL and CR versus BET + CR. Body composition did not differ between the groups. Dietary intake was unchanged throughout the study. Thus, we concluded that betaine supplementation does not augment muscle PCR content and betaine supplementation combined or not with creatine supplementation does not affect strength and power performance in non-resistance trained subjects

Ces travaux abordent, d'une part l'étude de la coordination du cuivre(II) et nickel(II) avec un ligand heptadenté tripode, et d'autre part la synthèse et la caractérisation de liquides ioniques dérivés de la bétaïne.Tout d'abord, le ligand heptadenté, le tris[(L)-alanyl-2-carboxamidoéthyl]amine (H3trenala), a été synthétisé sous forme de sel de chlorure ; ses constantes de protonation ainsi que les constantes de stabilité des complexes de Cu(II) et de Ni(II) ont été déterminées par potentiométrie. Des espèces complexes mononucléaires dans lesquels le ligand est protonné ([Cu(H5trenala)]4+, [M(H4trenala)]3+), neutre ([M(H3trenala)]2+) ou déprotonné ([M(H2trenala)]+, [M(Htrenala)]) (M = Cu2+ ou Ni2+) ont été mises en évidence. Seul le Cu(II) donne des espèces dinucléaires dans lesquels le ligand est uniquement déprotonné ([Cu2(H2trenala)]2+, [Cu2(Htrenala)]2+, [Cu2(trenala)]+, [Cu2(trenala)(OH)]). A l'état solide, deux complexes dinucléaires de cuivre(II) ont pu être isolés et caractérisés (IR, UV-Vis, masse électrospray, ATG). L'étude des propriétés catalytiques de ces deux complexes montre une faible activité vis-à-vis de la réaction d'oxydation du catéchol.La seconde partie de ce travail présente la synthèse de liquides ioniques constitués par des synthons cationiques dérivés d'ester de glycine-bétaïne {trialkyl(2-éthoxy-2-oxoéthyl)ammonium (alkyl = éthyl, n-propyl et n-butyl), N-(1-méthylpyrrolidyl-2-éthoxy-2oxoéthyl)ammonium} et des anions inorganiques {bis(trifluorosulfonyl)imide (NTf2-), dicyanamide (Dca-), tétrafluoroborate (BF4-)}. Les influences de la longueur de la chaîne alkyle portée par l'atome d'azote ammonium et de la nature de l'anion associé sur les propriétés physicochimiques telles que la densité, les températures de fusion, de transition vitreuse et de décomposition, la viscosité et les fenêtres électrochimiques, ont été déterminées. De plus, des sels fondus ont pu être générés à partir de ces cations organiques associés aux anions tetrafluoroborate, dicyanamide, hexafluorophosphate (PF6-) et perchlorate (ClO4-), et leurs propriétés physicochimiques ainsi que leurs structures cristallines ont été déterminées.Ensuite, les liquides ioniques hydrophobes sont utilisés pour l'extraction des cations métalliques [Cu(II), Ni(II), Cd(II) et Pb(II)] en phase aqueuse. Cette étude montre que les rendements d'extraction d'ions métalliques, déterminés par mesure de la concentration résiduelle en métal en phase aqueuse, dépendent de la longueur de la chaîne alkyle portée par l'atome d'azote ammonium et des propriétés chélatantes de l'anion. Les rendements les plus élevés ont été obtenus avec les liquides ioniques dont l'anion possède des propriétés chélatantes. L'étude du transfert du métal montre qu'il est dépendant de l'hydrophobicité du synthon cationique. Une augmentation de l'hydrophobicité du synthon cationique conduit à une augmentation du rendement d'extraction, tout en limitant l'échange ionique et en privilégiant une extraction par paires d'ions. Enfin, l'électrodéposition en phase liquide ionique et la désextraction liquide-liquide des ions métalliques ont été étudiées. / This work deals with copper(II) and nickel(II) complexation of a polydentate tripodal ligand and with, on a second part, the synthesis and characterization of ionic liquids derived from betaine and their use in liquid-liquid extraction.On the first part, a heptadentate ligand, tris[(L)-alanyl-2-carboxamidoethyl]amine (H3trenala), has been synthesized as its tetrahydrochloride salt; its protonation constants and the stability constants of the copper(II) and nickel(II) chelates have been determined by potentiometry. Mononuclear species with protonated, neutral, or deprotonated forms of the ligand, [Cu(H5trenala)]4+, [M(H4trenala)]3+, [M(H3trenala)]2+, [M(H2trenala)]+, and [M(Htrenala)] (M=Cu2+ and Ni2+) have been detected in all cases, while only Cu2+ gives dinuclear [Cu2(H2trenala)]2+, [Cu2(Htrenala)]2+, [Cu2(trenala)]+, and [Cu2(trenala)(OH)] species. Two dinuclear copper(II) complexes have been prepared and characterized by spectroscopic techniques (IR, UV-Vis, mass electro-spray) and thermogravimetric analysis. These two dinuclear copper(II) complexes have revealed weak catalytic activity in catechol oxidation.On the second part, a series of salts based on ethyl ester betaine derivatives[trialkyl(2-ethoxy-2-oxoethyl)ammonium or N-(1-methylpyrrolidyl-2-ethoxy-2-oxoethyl)ammonium cations] with alkyl chains [ethyl, n-propyl and n-butyl] have been synthesized. These cations generate hydrophobic ionic liquids with bis(trifluoromethylsulfonyl)imide, tetrafluoroborate or dicyanamide anions. The influence of the alkyl chain length and the chemical nature of the counteranion on physicochemical properties such as density, melting point, glass transition and decomposition temperatures, viscosity, and electrochemical window have been investigated. In addition, molten salts have been generated from these organic cations with hexafluorophosphate, perchlorate, tetrafluoroborate or dicyanamide anions. Their physicochemical properties and crystal structure have been investigated.The extraction of the different metal cations (Cu2+, Ni2+, Cd2+ and Pb2+) in aqueous solution by hydrophobic ionic liquids synthesized was performed. The extraction yields, determined by the measurements of the residual metal concentration in aqueous solution, depend not only the length of the alkyl chain of the ammonium but also on the nature of the associated anion. The most promising results are obtained with ILs whose anion has a chelating ability. The mechanism of metal transfer has been studied and was related to the hydrophobicity of the cationic synthon. Increasing the hydrophobicity of the cationic synthon leads to an increase of extraction yield, thus limiting the ion exchange and promoting ion pairing extraction. Electrodeposition in ionic liquid phase and liquid-liquid desextraction of metallic ions have also been investigated.

Les bétaïne lipides (BL) sont des lipides polaires qui se distinguent des phospholipides (PL)par l’absence de phosphore (P). La réorientation métabolique induite par une limitation en P chez des microalgues produisant des BL (Tisochrysis lutea et Diacronema lutheri, Haptophytes) ou en produisant peu (Phaeodactylum tricornutum, Bacillariophyte) a été comparée à celle induite par une limitation en azote (N). Le devenir et le flux de carbone dans différentes voies de biosynthèse ont été étudiés par une approche pluridisciplinaire.La limitation nutritive en P ou en N affecte différemment le métabolisme du carbone selon les espèces microalgales. La limitation en P réduit fortement l’activité photosynthétique et la respiration chez P. tricornutum et T. lutea. Par conséquent, l’accumulation de carbone est plus élevée que sous limitation en N chez ces deux espèces. Les deux limitations stimulent en particulier la synthèse des lipides neutres et / ou des glucides. Le remplacement des PL par les BL a été observé chez P. tricornutum en condition de limitation en P. Ce résultat est en accord avec une augmentation de la transcription du gène codant la bétaïne lipide synthase. En revanche, cette limitation ne modifie pas les teneurs en BL rapportées au carbone chez T. lutea et D. lutheri. La composition en acides gras des différentes classes lipidiques est modifiée selon l’espèce microalgale et l’élément nutritif limitant. Une attention particulière a été portée aux acides gras de la série oméga-3, notamment l’acide eicosapentaénoïque (EPA, 20:5 ω3) et l’acide docosahexaénoïque (DHA, 22:6 ω3) dont les proportions varient en fonction de l’élément limitant,de l’espèce et de la classe lipidique. L’augmentation de la production des lipides neutres et / ou des lipides polaires, notamment des bétaïne lipides, riches en DHA et/ou EPA induite par un stress nutritif laisse envisager une valorisation de ces molécules d’intérêt dans différents domaines dont la nutrition et la santé. / Betaine lipids (BL) are P-free polar lipids, conversely to phospholipids (PL). The metabolic reorientation induced by phosphorus (P) limitation in microalgae producing BL (Tisochrysis lutea and Diacronema lutheri, Haptophyta) or producing low levels of BL (Phaeodactylum tricornutum, Bacillariophyta) was compared to that induced by nitrogen (N) limitation. The carbon destiny and flow in different biosynthetic pathways were studied with a multidisciplinary approach. P or N limitation differently affected carbon metabolism according to microalgal species. P limitation highly decreased photosynthetic activity and respiration of P. tricornutum and T. lutea. Consequently, carbon accumulation was higher than under N limitation in these two species. Both limitations stimulated the synthesis of neutral lipids and / or carbohydrates. Replacement of PL by BL was observed in P. tricornutum under P limitation. This result is in agreement with a transcription increase of the gene encoding BL synthase. On the other hand, this limitation did not modify BL contents in reference with carbon in T. lutea or D. lutheri. Fatty acid composition of the different lipid classes was modified according to the microalgal species and the limiting nutrient. Particular attention was paid to the fatty acids of the omega-3 series, notably eicosapentaenoic acid (EPA, 20:5 ω3) and docosahexaenoic acid (DHA, 22:6 ω3), the proportions of which vary according to the limiting element, species and lipid class. The increase in the production of neutral lipids and / or polar lipids, especially betaine lipids, rich in DHA and / or EPA induced by nutritive stress suggests a valorization of these molecules of interest in various areas including nutrition and health.

The flavour or fragrance of Basmati rice is associated with the presence of 2-acetyl-1- pyrroline. This work shows that a gene with homology to betaine aldehyde dehydrogenase (BAD) has significant polymorphisms in the coding region of fragrant genotypes relative to non fragrant genotypes. Accumulation of 2-acetyl-1-pyrroline in fragrant rice genotypes may be explained by the presence of mutations resulting in loss of function of the fgr gene product. The fgr gene corresponds to the gene encoding BAD2 in rice while BAD1 is encoded by a gene on chromosome 4. Development of an allele specific amplification (ASA) based around the deletion in the gene encoding BAD2 allows, perfect, simple and low cost discrimination between fragrant and non-fragrant rice varieties and identifies homozygous fragrant, homozygous non-fragrant and heterozygous non-fragrant individuals in a population segregating for fragrance. The cDNAs transcribed from rice chromosomes 4 and 8, each encoding an enzyme with homology to betaine aldehyde dehydrogenase were cloned and expressed in E. coli. The enzyme responsible for fragrance, encoded from chromosome 8, had optimum activity at pH 10, showed low affinity towards betaine aldehyde (bet-ald) with Km value of approximately 63ìM but a higher affinity towards -aminobutyraldehyde (GABald) with a Km value of approximately 9ìM. The enzyme encoded from chromosome 4 had optimum activity at pH 9.5 and showed generally lower affinity towards most substrates compared to the enzyme encoded from chromosome 8, substrate specificities suggest that the enzymes have higher specificity to aminoaldehydes and as such both should be renamed as an aminoaldehyde dehydrogenase (AAD). The inactivation of AAD2 (BAD2) in fragrant rice varieties likely leads to accumulation of its main substrate GABald which then cyclises to 1-pyrroline the immediate precursor of 2AP.

<p>Pyrosequencing is a new DNA sequencing method relying on thesequencing-by-synthesis principle and bioluminometric detectionof nucleotide incorporation events. The objective of thisthesis was improvement of the Pyrosequencing method byincreasing the thermal stability of firefly luciferase, and byintroducing an alternative DNA polymerase and a new nucleotideanalog. Furthermore, the development of a new bioluminescentassay is described for the detection of inorganicpyrophosphatase activity.</p><p>The wild-type North American firefly<i>(Photinus pyralis)</i>luciferase is a heat-sensitiveenzyme, the catalytic activity of which is rapidly lost attemperatures over 30°C. Two strategies for increasing thethermostability of the enzyme are presented and discussed. Inthe first strategy, the solution thermodynamics of the systemis affected by osmolytes in such a way that heat-mediatedinactivation of the enzyme is prevented. In the secondstrategy, the enzyme is thermostabilized by mutagenesis. Bothstabilizing strategies can be utilized to allow bioluminometricassays to be performed at higher temperatures. For instance,both DNA polymerase and ATP sulfurylase activity could beanalyzed at 37°C.</p><p>The osmolyte strategy was successfully employed forincreasing the reaction temperature for the Pyrosequencingmethod. By increasing the reaction temperature to 37°Cunspecific signals from primer-dimers and 3’-end loopswere reduced. Furthermore, sequencing of a challenging templateat 37°C, which previously yielded poor, non-interpretablesequence signals at lower temperatures was now possible.</p><p>Introduction of a new adenosine nucleotide analog,7-deaza-2’-deoxyadenosine-5’-triphosphate (c⁷dATP) reduced the inhibitory effect on apyraseobserved with the currently used analog,2’-deoxyadenosine-5’-O-(1-thiotriphosphate)(dATPαS).</p><p>Sequencing of homopolymeric T-regions has previously beendifficult with the exonuclease-deficient form of the DNApolymerase I large (Klenow) fragment. By using the DNApolymerase from bacteriophage T7, known as Sequenase, templateswith homopolymeric T-regions were successfully sequenced.Furthermore, it was found that the strand displacement activityfor both polymerases was strongly assisted if the displacedstrand had a 5’-overhang. In contrast, the stranddisplacement activity for both polymerases was inhibitedwithout an overhang, resulting in reduced sequencingperformance in double stranded regions.</p><p>A firefly bioluminescent assay for the real-time detectionof inorganic pyrophosphatase in the hydrolytic direction wasalso developed. The assay is versatile and has a linearresponse in the range between 8 and 500 mU.</p><p><b>Key words:</b>bioluminescence, osmolytes, glycine betaine,thermostability, firefly luciferase, inorganic pyrophosphatase,inorganic pyrophosphate, Pyrosequencing technology, secondaryDNA-structures, Sequenase, Klenow-polymerase, reaction rates,temperature, c⁷dATP, dATPαS.</p>

The flavour or fragrance of Basmati rice is associated with the presence of 2-acetyl-1- pyrroline. This work shows that a gene with homology to betaine aldehyde dehydrogenase (BAD) has significant polymorphisms in the coding region of fragrant genotypes relative to non fragrant genotypes. Accumulation of 2-acetyl-1-pyrroline in fragrant rice genotypes may be explained by the presence of mutations resulting in loss of function of the fgr gene product. The fgr gene corresponds to the gene encoding BAD2 in rice while BAD1 is encoded by a gene on chromosome 4. Development of an allele specific amplification (ASA) based around the deletion in the gene encoding BAD2 allows, perfect, simple and low cost discrimination between fragrant and non-fragrant rice varieties and identifies homozygous fragrant, homozygous non-fragrant and heterozygous non-fragrant individuals in a population segregating for fragrance. The cDNAs transcribed from rice chromosomes 4 and 8, each encoding an enzyme with homology to betaine aldehyde dehydrogenase were cloned and expressed in E. coli. The enzyme responsible for fragrance, encoded from chromosome 8, had optimum activity at pH 10, showed low affinity towards betaine aldehyde (bet-ald) with Km value of approximately 63ìM but a higher affinity towards -aminobutyraldehyde (GABald) with a Km value of approximately 9ìM. The enzyme encoded from chromosome 4 had optimum activity at pH 9.5 and showed generally lower affinity towards most substrates compared to the enzyme encoded from chromosome 8, substrate specificities suggest that the enzymes have higher specificity to aminoaldehydes and as such both should be renamed as an aminoaldehyde dehydrogenase (AAD). The inactivation of AAD2 (BAD2) in fragrant rice varieties likely leads to accumulation of its main substrate GABald which then cyclises to 1-pyrroline the immediate precursor of 2AP.

A betaína é um trimetil derivado do aminoácido glicina. Os seus principais efeitos fisiológicos são atuar como um osmólito e como doador de radicais metil. Especulase que a betaína possa contribuir para a síntese de creatina no músculo esquelético pelo fornecimento de grupos metil, resultante da conversão de betaína em dimetilglicina, para a remetilação de homocisteína em metionina. Os efeitos da suplementação de creatina sobre o desempenho são conhecidos e relacionam-se principalmente ao aumento na ressíntese de fosforilcreatina (PCR). Autores de estudos recentes têm atribuído seus resultados positivos em relação ao aumento de força muscular a um possível efeito da betaína sobre as concentrações de PCR. Essa variável, entretanto, não foi avaliada, de maneira que os mecanismos responsáveis pelo aumento de força advindo da suplementação de betaína ainda são inexplorados em humanos. Diante disso, este estudo teve como objetivo investigar os efeitos da suplementação de betaína, combinada ou não com a suplementação de creatina, sobre as concentrações intramusculares de PCR, e a produção de força e potência muscular em indivíduos não treinados em força. Além disso, as respostas fisiológicas e ergogênicas da suplementação de betaína e creatina foram comparadas e avaliados os possíveis efeitos aditivos desses suplementos. Foi conduzido um estudo duplo-cego, randomizado, controlado por placebo. Trinta e quatro sujeitos foram divididos em quatro grupos: Betaína (BET; 2 g/dia), Creatina (CR; 20 g/dia), Betaína + Creatina (BET + CR; 2 + 20 g/dia) e Placebo (PL). No período basal (PRÉ) e após 10 dias de suplementação (PÓS), os indivíduos submeteram-se a avaliações do consumo alimentar e da composição corporal, a testes de força e potência muscular e à quantificação intramuscular de PCR. Após a intervenção, as concentrações intramusculares de PCR foram maiores nos grupos CR e BET + CR, quando comparados ao grupo PL (p = 0,004 e p = 0,006, respectivamente). Não houve diferenças significativas entre os grupos BET e PL (p = 0,78) e CR e BET + CR (p = 0,99). Os grupos CR e BET + CR apresentaram maior produção de potência muscular no exercício de agachamento, quando comparados ao grupo PL (p = 0,003 e p = 0,041, respectivamente). Resultados similares foram encontrados para o exercício de supino. Os grupos CR e BET + CR também demonstraram aumento significativo de força muscular (teste de 1-RM) do teste PRÉ para o teste PÓS nos exercícios de supino e agachamento (CR: p = 0,027 e p 0,0001; BET + CR: p = 0,03 e p 0,0001 para membros superiores e inferiores, respectivamente). Não houve diferenças significativas para os testes de força e de potência muscular entre os grupos BET e PL e os grupos CR e BET + CR. Também não houve diferença significativa entre os grupos para a composição corporal. O consumo alimentar permaneceu inalterado ao longo do estudo. Os resultados permitem concluir que a suplementação de betaína, combinada ou não com a suplementação de creatina, não aumenta o conteúdo intramuscular de PCR e não afeta o desempenho de força e de potência muscular / Betaine is a trimethyl derivative of the amino acid glycine. The main physiological functions of betaine are to act as an organic osmolyte and as a donor of methyl radicals. It is speculated that betaine may contribute to the synthesis of creatine in skeletal muscle through the donation of a methyl group, resulting from the conversion of betaine to dimethylglycine, to homocysteine to form methionine. The effects of creatine supplementation on performance are well known and are related primarily to an increase in fosforilcreatina resynthesis (PCR). Authors of recent studies have attributed its positive results regarding the increase of muscle strength to a possible effect of betaine on the concentrations of PCR. However, this variable was not assessed, so that the mechanisms responsible for the increase in muscle strength coming from betaine supplementation in humans are still unexplored. In light of this, the aim of this study was to investigate the effect of betaine supplementation combined or not with creatine supplementation on muscle PCR content, muscle strength and power output in non-resistance trained subjects. Additionally, we compared the ergogenic and physiological responses to betaine versus creatine supplementation. Finally, we also tested the possible additive effects of creatine and betaine supplementation. A randomized, double-blind, placebo-controlled study was conducted. Thirty and four subjects were assigned into four groups: Betaine (BET; 2 g/day), Creatine (CR; 20 g/day), Betaine + Creatine (BET + CR; 2 + 20 g/day) or Placebo (PL). At baseline (PRE) and after 10 days of supplementation (POST) body composition, food intake, muscle strength and power and muscle PCR were assessed. The CR and BET + CR groups presented greater increase in muscle PCR content than PL (p = 0.004 and p = 0.006, respectively). PCR content was comparable between BET versus PL (p = 0.78) and CR versus BET + CR (p = 0.99). CR and BET + CR presented greater muscle power output than PL in the squat exercise following supplementation (p = 0.003 and p = 0.041, respectively). Similarly, bench press average power was significantly greater for the CR-supplemented groups. CR and BET + CR groups also showed significant pre- to post-test increase in 1-RM squat and bench press (CR: p = 0.027 and p 0.0001; BET + CR: p = 0.03 and p 0.0001 for upper- and lower-body assessments, respectively). No significant differences for 1-RM strength and power were observed between BET versus PL and CR versus BET + CR. Body composition did not differ between the groups. Dietary intake was unchanged throughout the study. Thus, we concluded that betaine supplementation does not augment muscle PCR content and betaine supplementation combined or not with creatine supplementation does not affect strength and power performance in non-resistance trained subjects