The present study investigated the effects of glutaric acid (GA), which predominantly accumulates in glutaric acidemia type I (GA-I), on some in vitro parameters of energy metabolism in cerebral cortex of rats. We first evaluated CO2 production from [U-14C] acetate, as well as ATP levels in brain of young Wistar rats. The effect of the acid on the activities of the respiratory chain complexes were also investigated. GA was tested at final concentrations ranging from 0.5 to 5.0 mM. GA significantly reduced brain CO2 production by 50% at the concentrations of 0.5 to 3.0 mM, ATP levels by 25% at the concentration of 3.0 mM, succinate:cytochrome C oxireductase (complex II plus CoQ plus complex III) by 25% at 5 mM concentration, and NADH:cytochrome C oxireductase (complex I plus CoQ plus complex Ill) by 25% at 2.5 and 5 mM concentrations. The results strongly indicate that GA impairs brain energy production. If these effects also occur in humans, it is possible that they may contribute to the neuropathology of patients affected by GA-I.

EXPLORATORY ANALYSIS APPLIED TO ATTENUATED TOTAL REFLECTANCE FOURIER TRANSFORM INFRARED (ATR-FTIR) OF BIODIESEL/DIESEL BLENDS. In this study, hierarchical cluster analysis (HCA) and principal component analysis (PCA) were used to classify blends produced from diesel S500 and different kinds of biodiesel produced by the TDSP methodology. The different kinds of biodiesel studied in this work were produced from three raw materials: soybean oil, waste cooking oil and hydrogenated vegetable oil. Methylic and ethylic routes were employed for the production of biodiesel. HCA and PCA were performed on the data from attenuated total reflectance Fourier transform infrared spectroscopy, showing the separation of the blends into groups according to biodiesel content present in the blends and to the kind of biodiesel used to form the mixtures.Keywords: HCA; PCA; diesel/biodiesel blends; exploratory analysis. INTRODUÇÃOO estudo de combustíveis alternativos aos derivados petroquí-micos tem recebido grande estímulo na última década no Brasil, especialmente com o desenvolvimento dos programas de incentivo a produção de novas matrizes energéticas, como é o caso do biodiesel adicionado ao óleo diesel mineral.A utilização do óleo diesel como combustível teve seu início amplamente reconhecido quando Rudolf Diesel patenteou o seu motor em 1892 e introduziu o primeiro motor diesel destinado a funcionar com óleo vegetal. Em 1900, ele abasteceu e utilizou o motor com óleo de amendoim por várias horas, com sucesso. Já em 1912, ele previu que, no futuro, o óleo vegetal poderia ser um combustível importante assim como o óleo diesel.1 Por razões tanto técnicas quanto econômicas, com o passar do tempo os óleos deram lugar ao diesel mineral.2 Na época, o baixo preço e a oferta abundante dos derivados de petróleo resultaram na escolha pelo diesel de petróleo. Em 1940, enormes reservatórios de petróleo foram encontrados, sua extração e refinamento foram relativamente fáceis e baratos. Em 1970, o monopólio de algumas nações e circunstâncias políticas geraram uma nova situação, o que obrigou os engenheiros e pesquisadores a desenvolver combustíveis alternativos e ambientalmente amigáveis. Desde então, há um interesse renovado na utilização de derivados de óleos vegetais em motores a diesel por várias razões, incluindo considerações políticas, preocupações ambientais e aspectos econômicos. Neste sentido, o biodiesel, que é constituído de uma mistura de alquil-ésteres de cadeia linear, é obtido pela reação de transesterificação dos triglicerídeos presentes em óleos e gorduras com álcoois de cadeia curta gerando como subproduto o glicerol. A importância do biodiesel como aditivo e até como possível substituinte do óleo diesel decorre do fato de que este biocombustível apresenta vantagens sobre o óleo diesel, pois é proveniente de fontes renováveis, não é tóxico e diminui as emissões de poluentes durante a sua combustão.4 O biodiesel produz cerca de 10% menos de energia que o diesel de petróleo, mas seu desempenho no motor é praticamente o mesmo em t...

. In this work, Doehlert experimental design was used to optimize the Transesterification Double Step Process (TDSP) method of methyl soybean oil biodiesel production which starts with a basic catalysis followed by an acidic catalysis. The conversion values were calculated from NMR spectra. Response surface was used to show the results of the interactions between the variables. This experimental design evaluated variables like catalyst and alcohol amount for the basic catalysis and time and temperature for the acidic catalysis. According to results obtained after Doehlert design application the alcohol amount was the main factor that influenced on the basic catalysis but for the acidic catalysis both time and temperature are important and their effects are opposite. It resulted on excellent conversions for both steps obtaining for the basic catalysis about 100% when was used like optimal conditions catalyst amount equal to 0.40 g and volume of methanol equal to 60 mL and for the acidic catalysis about 99% when was used like optimal conditions temperature of 65 °C and 90 minutes for reaction time.Keywords: transesterification double step process; biodiesel; NMR; Doehlert design. INTRODUÇÃOA produção de biodiesel, já bem consolidada no Brasil e no mundo, há mais de uma década, é um assunto que continua a atrair interesse de vários setores, especialmente da indústria de biocombustíveis e dos pesquisadores em geral, uma vez que sempre há o objetivo de aumentar a qualidade e aprimorar o processo de produção deste combustível ainda muito valorizado. 1Este tema é um setor importante para a economia nacional que ainda necessita tanto do desenvolvimento de novas tecnologias quanto soluções para questões econômicas e sociais.2 Neste sentido, atualmente, há necessidade de pesquisas para diversas finalidades: diversificar fontes de matéria-prima, incluindo renováveis 3 ou óleos residuais, 4 diminuir custos de produção, criar novas metodologias de produção, 5 melhorar características físico-químicas, 6 qualidade e consequente rendimento e emissões do motor, 7 entre outros. O processo de transesterificação em duas etapas (TDSPTransesterification Double Step Process) utilizado neste estudo foi inicialmente desenvolvido por Samios et al. para produzir biodiesel metílico a partir de alguns óleos clássicos no Brasil como girassol e linhaça, por ser um método simples e rápido de síntese, que facilita o procedimento de separação dos produtos e resulta em ótima eficiência de conversão.8 Ao longo dos anos também vem sendo aprimorada desde a sua criação, resultando na aplicação para produção de biodiesel etílico também, 9 além de possibilitar o uso de outras fontes de matéria-prima, como banha, sebo e a reutilização de óleo de fritura por exemplo. 10Neste estudo é proposta a inserção do planejamento experimental Doehlert, 11 que foi desenvolvido por David H. Doehlert em 1972, como um instrumento para otimizar as condições de síntese do biodiesel produzido pelo método TDSP. Modelos multivariados, como é o caso do planejamento Doehlert,...

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In the present study we investigated the effects of L-pyroglutamic acid (PGA), which predominantly accumulates in the inherited metabolic diseases glutathione synthetase deficiency (GSD) and gamma-glutamylcysteine synthetase deficiency (GCSD), on some in vitro parameters of energy metabolism and lipid biosynthesis. We evaluated the rates of CO2 production and lipid synthesis from [U-14C]acetate, as well as ATP levels and the activities of creatine kinase and of the respiratory chain complexes I-IV in cerebral cortex of young rats in the presence of PGA at final concentrations ranging from 0.5 to 3 mM. PGA significantly reduced brain CO2 production by 50% at the concentrations of 0.5 to 3 mM, lipid biosynthesis by 20% at concentrations of 0.5 to 3 mM and ATP levels by 52% at the concentration of 3 mM. Regarding the enzyme activities, PGA significantly decreased NADH:cytochrome c oxireductase (complex I plus CoQ plus complex III) by 40% at concentrations of 0.5-3.0 mM and cytochrome c oxidase activity by 22-30% at the concentration of 3.0 mM, without affecting the activities of succinate dehydrogenase, succinate:DCPIP oxireductase (complex II), succinate:cytochrome c oxireductase (complex II plus CoQ plus complex III) or creatine kinase. The results strongly indicate that PGA impairs brain energy production. If these effects also occur in humans, it is possible that they may contribute to the neuropathology of patients affected by these diseases.

Abstract2-Hydroxybutyric acid appears at high concentrations in situations related to deficient energy metabolism (e.g., birth asphyxia) and also in inherited metabolic diseases affecting the central nervous system during neonatal development, such as cerebral lactic acidosis, glutaric aciduria type II, dihydrolipoyl dehydrogenase (E 3 ) deficiency, and propionic acidemia. The present study was carried out to determine the effect of 2-hydroxybutyric acid at various concentrations (1-10 mM) on CO 2 production and lipid synthesis from labeled substrates in cerebral cortex of 30-day-old Wistar rats in vitro. CO 2 production was significantly inhibited (30-70%) by 2-hydroxybutyric acid in cerebral cortex prisms, in total homogenates and in the mitochondrial fraction. We also demonstrated a significant inhibition of lipid synthesis (20-45%) in cerebral cortex prisms and total homogenates in the presence of 2-hydroxybutyric acid. However, no inhibition of lipid synthesis occurred in homogenates free of nuclei and mitochondria. The results indicate an impairment of mitochondrial energy metabolism caused by 2-hydroxybutyric acid, a fact that may secondarily lead to reduction of lipid synthesis. It is possible that these findings may be associated with the neuropathophysiology of the situations where 2-hydroxybutyric acid is accumulated.

Multivariate calibration models based on data from mid-infrared spectroscopy of biodiesel/diesel blends were obtained. The blends were prepared from diesel oil and esters of soybean oil, waste cooking oil, and hydrogenated vegetable oil in proportions ranging from 0 to 100 % biodiesel. The results showed that the multivariate regression models with interval partial least squares (iPLS), backward interval partial least squares (biPLS), and synergy interval partial least squares (siPLS) were able to determine the fractions of the infrared spectrum that contain the relevant information for estimating the values of physicochemical properties, flash point, specific gravity, and cetane number, which are used in quality control of the blends. In the best models, the values of determination coefficients were greater than 0.9500, proving their efficiency as an alternative to traditional analytical methods.

4-Hydroxybutyric acid (4HB) is accumulated in succinic semialdehyde dehydrogenase deficiency, an inherited metabolic disease severely affecting the CNS during postnatal development. Thus, the present study was designed to evaluate the in vitro influence of 4HB on lipid synthesis and CO2 production from [U-14C] acetate in cerebral cortex of 30-day-old Wistar rats. In the presence of 4HB, there was an inhibition of lipid synthesis in cerebral cortex prisms and homogenates. However, no inhibition of lipid synthesis occurred in the homogenates free of nuclei and mitochondria. In addition, CO2 production was inhibited by 4HB in cerebral cortex prisms, and homogenates and in the mitochondrial fraction. These results might possibly be explained by an impairment of mitochondrial metabolism by 4HB which may secondarily inhibit lipid synthesis. The results reported here may help to better understand the neuropathophysiology of 4-hydroxybutyric aciduria.