Fatty Acid Biosynthesis from Chlorella in Autotrophic and Mixotrophic Cultivation

Abstract Microalgae are photosynthetic microorganisms whose composition and biomass production can be influenced by manipulating the cultivation conditions employed. However, few studies have evaluated the effects of various cultivation conditions in autotrophic and mixotrophic conditions. The present work aimed to evaluate the effects of cultivation conditions on the cell growth and biosynthesis of fatty acids (FAs) by microalgae of the genus Chlorella in autotrophic and mixotrophic cultivation. Evaluation of the effects of the conditions was performed using an experimental design methodology. The highest values of maximum biomass concentration (Xmax) and maximum biomass productivity (Pmax) were obtained in autotrophic cultures. Palmitic acid was the FA obtained at the highest concentration in both cultivation modes. The concentrations of polyunsaturated FAs (PUFAs) ranged from 12.2 to 41.2% in autotrophic cultures and from 11 to 34.3% in the mixotrophic cultures. The variables photoperiod and sodium bicarbonate concentration showed the greatest influence on the Xmax, Pmax, and PUFA concentration in autotrophic and mixotrophic cultivations, respectively. This study verified that the selection of conditions and mode of cultivation contribute to the production of microalgal biomass and FA biosynthesis.

A comparative study of coastal and clinical isolates of Pseudomonas aeruginosa

Pseudomonas aeruginosa is a ubiquitous Gram-negative bacterium having a versatile metabolic potential and great ecological and clinical significance. The geographical distribution of P. aeruginosahas revealed the existence of an unbiased genetic arrangement in terrestrial isolates. In contrast, there are very few reports about P. aeruginosa strains from marine environments. The present work was aimed at studying the distribution of P. aeruginosa in coastal waters along the Indian Peninsula and understanding the environmental influence on genotypic, metabolic and phenotypic characteristics by comparing marine and clinical isolates. Of the 785 marine isolates obtained on selective media, only 32 (~4.1%) were identified as P. aeruginosa, based on their fatty acid methyl ester profiles. A low Euclidian distance value (< 2.5) obtained from chemotaxonomic analysis suggested that all the environmental (coastal and marine) isolates originated from a single species. While UPGMA analyses of AP-PCR and phenotypic profiles separated the environmental and clinical isolates, fatty acid biotyping showed overlapping between most clinical and environmental isolates. Our study revealed the genetic diversity among different environmental isolates of P. aeruginosa. While biogeographical separation was not evident based solely on phenotypic and metabolic typing, genomic and metatranscriptomic studies are more likely to show differences between these isolates. Thus, newer and more insightful methods are required to understand the ecological distribution of this complex group of bacteria.

Nitro-fatty acids: novel anti-inflammatory lipid mediators

Nitro-fatty acids are formed and detected in human plasma, cell membranes, and tissue, modulating metabolic as well as inflammatory signaling pathways. Here we discuss the mechanisms of nitro-fatty acid formation as well as their key chemical and biochemical properties. The electrophilic properties of nitro-fatty acids to activate anti-inflammatory signaling pathways are discussed in detail. A critical issue is the influence of nitroarachidonic acid on prostaglandin endoperoxide H synthases, redirecting arachidonic acid metabolism and signaling. We also analyze in vivo data supporting nitro-fatty acids as promising pharmacological tools to prevent inflammatory diseases.

Composición en ácidos grasos de leche de madres de recién nacidos de pretérminoy de término / Fatty acid composition of human milk from mothers of preterm and full-term infants

Introducción. La leche materna es un alimento esencial para el recién nacido e influye en su calidad de vida en el corto y largo plazo. Su composición se modifica con el estado nutricional,la dieta materna y la edad gestacional del recién nacido. Entre otros nutrientes fundamentales provee a los lactantes de ácidos grasos de cadena media de fácil utilización, y de ácidos grasosesenciales y sus derivados metabólicos, en especial ácidos araquidónico y docosahexaenoico, que han sido involucrados en la maduración neural.Objetivos. Dada la escasez de datos locales se consideró la importancia de estudiar la composición en ácidos grasos de la leche de madres de reciénnacidos de pretérmino y de término en mujeres del área urbana de la Provincia de Buenos Aires.Material y métodos. Las muestras fueron obtenidas del Banco de Leche Materna H.I.G.A San Martín. Se extrajeron los lípidos totales y se determinó la composición en ácidos grasos porcromatografía de gas-líquido.Resultados. Los resultados muestran aumentos en ácidos grasos saturados de hasta 14 átomos de carbono y en los ácidos grasos poliinsaturadosen la leche de madres de recién nacidos de pretérmino con respecto a la de madres de recién nacidos de término.Conclusiones. La edad gestacional influye en la composición de los ácidos grasos de la leche materna, siendo la leche de madres de lactantesprematuros una fuente imprescindible de elementos energéticos (ácidos grasos saturados) y de elementos plásticos (ácidos grasos poliinsaturados)fundamentales para la síntesis de lípidosestructurales y en el desarrollo neural.

Abordagem racional no planejamento de novos tuberculostáticos: inibidores da InhA, enoil-ACP redutase do M. tuberculosis: [revisão] / Rational approach in the new antituberculosis agent design: inhibitors of InhA, the enoyl-ACP reductase from Mycobacterium tuberculosis: [review]

Associada à disseminação da infecção causada pelo HIV, a tuberculose (TB) é considerada, atualmente, problema mundial de saúde pública devido às proporções que vem assumindo. A resistência micobacteriana aos fármacos utilizados na terapêutica é a principal causa da reincidência da TB. Diante deste quadro alarmante, o desenvolvimento de novos e seletivos fármacos anti-TB se faz urgente e necessário. A biossíntese de ácidos graxos é um processo bioquímico realizado por procariotos e eucariotos, o qual fornece precursores essenciais à montagem de componentes celulares importantes, tais como fosfolipídeos, lipoproteínas, lipopolissacarídeos, ácidos micólicos e envelope celular. As diferenças bioquímicas e funcionais entre o mecanismo biossintético de ácidos graxos em bactérias e mamíferos tornam-no alvo relevante ao planejamento de novos antibacterianos, mais seletivos e menos tóxicos. As enoil-ACP redutases são enzimas cruciais à etapa de alongamento de ácidos graxos, considerados produtos intermediários na biossíntese de ácidos micólicos - os principais componentes da parede celular micobacteriana. Portanto, tais enzimas são tidas como alvos moleculares no planejamento racional de novos tuberculostáticos. Avanços recentes no processo de descoberta de novos agentes anti-TB, particularmente os inibidores da enoil-ACP redutase, serão discutidos nesta revisão.

In conjunction with the spread of HIV infection, tuberculosis (TB) has been among the worldwide health threats. Mycobacteria resistance to the drugs currently used in the therapeutics is the main cause of TB resurgence. In view of this severe situation, the new and selective anti-TB design is of utmost importance. Fatty acid biosynthesis is a prokariontes and eucariontes biochemical process that supplies essential precursors for the assembly of important cellular components, such as phospholipids, lipoproteins, lipopolysaccharides, mycolic acids and cellular envelope. However, the biochemical and functional differences between the bacterial and mammals' fatty acid synthetic pathway have endowed the mycobacterial enzymes with distinct properties. These provide valuable opportunities for structure- or catalytic mechanism-based design of selective inhibitors as novel anti-TB drugs with improved properties. The enoyl-reductases are essential enzymes in the fatty acids elongation pathway towards the mycolic acids, the main mycobacteria cell wall constituents, biosynthesis and so they are potential targets to the rational new antimycobacteria drug design. This paper highlights recent approaches regarding the design of new anti-TB agents, particularly, the enoyl-ACP reductase inhibitors.

Mecanismo de acción de las proteínas que se unen a los elementos regulatorios de esteroles (SREBPs) en la biosÝntesis del colesterol y ßcidos grasos / Mechanism of action of sterol regulatory element binding proteins (SREBPs) in cholesterol and fatty-acid biosynthesis

Cholesterol is an important lipid in higher organisms, and its concentration must be maintained in narrow limits depending of the cell needs. An excess of dietary cholesterol can lead to serious health problems, however, if consumption of this lipid is restricted in the diet, cells have the capacity to synthesize it. For the synthesis of cholesterol, the cell uses a family of proteins named sterol regulatory element binding proteins (SREBP's), that are transcriptional factors involved in the control of expression of genes of cholesterol and fatty acids synthesis. SREBP's regulate gene transcription by binding to cis-acting elements denominated sterol regulatory elements (SRE-1). SREBP's are localized in the endoplasmic reticulum, but in the event that the cell needs to synthesize cholesterol, the NH2-terminal portion of these proteins is cleaved by two specific proteases, and then travels into the nucleus to function as transcriptional factor. The present review shows the details of the mechanism that the cell uses to regulate cholesterol biosynthesis by the SREBP's, and its potential metabolic implications.

Consistência da gordura abdominal de frango, de suas estearinas e de suas misturas binárias com toucinho / Consistency of abdominal chiken fat, of its stearins and of its binary mixtures with bacon fat

A consistência é uma das propriedades físicas mais importantes das gorduras, pois se encontra diretamente associada às suas diversas aplicações. Esta propriedade pode ser considerada como um aspecto funcional relevante das gorduras plásticas, que säo misturas de cristais de gordura sólida e óleo líquido. Os cristais de gordura formam uma rede tridimensional, que comunica plasticidade ao material. O objetivo deste trabalho foi analisar as interações que ocorrem em misturas binárias de duas gorduras animais (abdominal de frango e de toucinho) quanto a sua propriedade de consistência em diferentes temperaturas.

Enzymes of glycolytic and pentose phosphate pathways in cytosolic and leucoplastic fractions of developing seeds of Brassica campestris.

Distribution of the enzymes of glycolytic and pentose phosphate pathways were studied in cytosolic and leucoplastic fractions of the developing seeds of Brassica. Leucoplasts were isolated using a discontinuous percoll gradient. Intactness of leucoplasts was checked by ADP-glucose pyrophosphorylase assay in presence and absence of triton X-100. No contamination by microbodies, mitochondria and cytosol was observed as assessed by measuring the activities of marker enzymes. The recovery, latency and specific activity of each enzyme in different fractions were compared. The leucoplastic fraction contained complete set of the enzymes of glycolytic and pentose phosphate pathways, indicating that the two subcellular compartments metabolize carbon independently by these pathways. However, the enzymes showed higher activities in cytosolic fraction as compared to those in the leucoplasts, suggesting the need for exchange of metabolites in the two compartments through various translocators, for acting in cooperation to produce energy, reducing power and carbon skeletons for different biosynthetic activities in the non-photosynthetic plastids. Based on these compartmentation studies, a model for carbon flow for fatty acid synthesis in leucoplasts of developing Brassica seeds has been proposed.

Fatty acid synthesis by isolated leucoplasts from developing Brassica seeds: role of glycolytic intermediates as the source of carbon and energy.

Fatty acid synthesis from Na [1-14C] acetate in leucoplasts isolated from developing seeds of Brassica campestris was completely dependent on exogenous supply of ATP. None of the intermediates of glycolysis or pentose phosphate pathway tested could replace ATP in the reaction mixture. In absence of exogenously supplied ATP, maximum activity was obtained with glu-6-P (68%) followed by fru-6-P (50%) and PEP (44%), respectively. With other intermediates as energy sources, the activity ranged from 1 to 38%. In complementary experiments (presence of ATP), none of the metabolites gave activity higher than the ATP control activity. Under optimum conditions for fatty acid synthesis from acetate, Brassica leucoplasts readily utilized labelled glucose as the substrate for fatty acid synthesis. Omission of NADH and NADPH individually from the reaction mixtures containing labelled glucose resulted only in 46 and 20% loss in activity, respectively, compared to the corresponding losses of 56 and 50%, when labelled acetate was used as the substrate. Similarly, deletion of ATP from the reaction mixture containing glucose as the substrate decreased the rate of fatty acid synthesis by about 65%, while the corresponding decrease with acetate as the substrate was 96%. Inclusion of 5 mM cold acetate, pyruvate, malate and glu-6-P in the reaction mixture containing glucose as the labelled substrate reduced label incorporation into fatty acids by 38 to 69%, maximum reduction being observed with pyruvate followed by glu-6-P, acetate and malate, respectively. With labelled acetate as the substrate, maximum reduction in label incorporation was obtained with cold glucose (5 mM) followed by glu-6-P, pyruvate and malate, respectively. The study demonstrated the operation of complete glycolytic pathway in Brassica leucoplasts, allowing the plastids to use glucose as a source of carbon, reducing power and energy for fatty acid synthesis.

Adrenoleucodistrofia ligada al cromosoma X: informe de dos casos clínicos / Adrenoleukodystrophy linked with chromosome X. Report of two clinical cases

La adrenoleucodistrofia infantil es un trastorno peroxisomal caracterizado por una falla en la función de la lignoceroil CoA sintetasa, se transmite en forma reseciva ligada al cromosoma X, con localización el locus 28 (q28). La deficiencia enximática condiciona una degradación imcompleta de los ácidos grasos de cadena larga, acumulándose en consecuencia en el tejido cerebral y adrenal. El motivo del presente trabajo es identificar los hallazgos clínicos encontrados en estos casos donde incluímos la presencia del asma bronquial, manifestaciones endocrinológicas y neurológicas. Los pacientes fueron tratados en el servicio a partir de 1990. Se describen los métodos utilizados para el diagnóstico, desde las alteraciones tempranas de los potenciales evocados de tallo, hasta las imágenes de tomografía computarizada de cráneo con doble cantidad de medio de contraste, y cortes tardíos

Efectos del acipimox sobre el metabolismo de la glucosa y de los lípidos, en pacientes con diabetes mellitus tipo II, obesos de difícil control con hiperlipoproteinemia tipo IIb y IV: resultados de un estudio multicéntrico / Acipimox affects in glucose metabolism in patients with diabetes mellitus type II and hyperlipidemia type IIb or IV

La interacción metabólica entre hidratos de carbono y lípidos, ha permitido considerar la hipótesis de que la corrección con hiperlipidemia en el diabético mal controlado, permite al paciente mejorar su control glucémico, posiblemente modificando la resistencia a la insulina. El objetivo de este trabajo multicéntrico fue evaluar la acción de un hipolipemiante, un análogo del ácido nicotínico acipimox en pacientes diabéticos no insulino dependientes con hiperlipoproteinemia tipo IIb y IV, que presentaban un descontrol metabólico aún recibiendo hipoglucemiantes orales a dosis máximas. La investigación incluyó 133 pacientes, de los que 67 tomaron acipimox por un periodo de tres meses (olbetam, *marca registrada) en dosis de 250 mg tres veces por vía oral; y 66 pacientes (grupo control) a quienes se les administró placebo. Se examinaron diversos parámetros bioquímicos antes de la administración del medicamento, a las cuatro, ocho y 12 semanas. En el grupo con acipimox se observó una disminución estadísticamente significativa de los niveles plasmáticos de triglicéridos, colesterol total, colesterol LDL, glucosa en ayuno y postprandial, hemoglobina glucosilada y un incremento de colesterol HDL. Estos resultados indican que el acipimox es un agente hipolipidemico con efecto sobre el control metabólico, tanto de los lípidos como de la glucosa, en pacientes diabéticos tipo II con hiperlipidemia tipo IIb o IV de difícil control

Estabilidade biológica de bebida de baixa graduaçäo alcoólica, com uso dos ácidos octanóico e decanóico / Biological stability of low alcohol beverages using decanoic and octanoic acids

No presente trabalho foi estudado o emprego de ácidos graxos (octanóico e decanóico) como agentes de estabilizaçäo biológica de bebidas de baixa graduaçäo alcoólica de 6 a 7oGL (sidra e vinho) com açucar residual fermentável. Três cepas de leveduras foram empregadas no teste: Zygosaccharomyces bailii, Candida valida e Saccharomyces cerevisiae. Três níveis de ácidos graxos foram testados: 25, 50 e 75mg/l. As cepas testadas apresentaram-se mais sensíveis ao ácido decanóico. Na concentraçäo de 75mg/l, o ácido decanóico inibiu o crescimento de S.cerevisiae e C.valida, tanto em vinho quanto em sidra, porém, näo inibiu o crescimento de Z. bailli, uma levedura comum como deteriorante de bebidas e extremamente resistente à açäo dos ácidos lipolíticos frescos usados como conservantes em alimentos. Testou-se também a açäo sinergística de ácido sórbico (S) e ácido decanóico (D) em duas combinaçöes inibiu o crescimento de S. cerevisiae, demonstrando um efeito maior do que seria esperado a partir da simples soma dos efeitos isolados desses dois agentes. Os valores de "threshold" do ácido decanóico e octanóico foram abaixo de 8mg/l, portanto, muito aquém dos teores necessários para que os mesmos atuassem como agentes conservadores. Constatou-se que, embora os referidos ácidos graxos apresentem poder inibidor sobre S.cerevisiae e C.valida, näo poderäo ser empregados em funçäo de conferirem odor e sabor estranhos à bebida

Acidos graxos omega III: uma revisao / Marine omega III fatty acids: a review

A baixa mortalidade de esquimos por coronariopatia, tem sido relacionada a alta quantidade de peixe que eles consomem. A adicao do acido eicosapentanoico, um oleo de peixe marinho, na dieta humana, mostra a producao de metabolitos que sao menos potentes que seus assemelhados derivados do acido araquidonico. Devido as diferentes atividades funcionais destes eicosanoides, muitas pesquisas estao sendo feitas com outras patologias. O objetivo desta revisao e mostrar alguns trabalhos e resultados com o uso destas substancias.