Estudio de enzimas implicadas en el intercambio de acilos y la síntesis de glicerolípidos en el retículo endoplásmico de girasol (helianthus annuus)

Las propiedades y, por tanto, los usos de los aceites vegetales, vienen determinados por la composición de acilo de los triacilgliceroles (TAG), componente principal del aceite. Por ello, en la actualidad, se realizan numerosos trabajos enfocados en modificar la composición de ácidos grasos de los mismos para adaptarlos a los requerimientos de la industria. Para poder realizar tales modificaciones de forma eficaz, es necesario comprender los aspectos fundamentales de cómo las plantas sintetizan, modifican y acumulan los ácidos grasos en los TAG del aceite de semilla. En este sentido, la enzima lisofosfatidilcolina aciltransferasa (LPCAT), implicada en la transferencia de grupos acilos hacia o desde la fosfatidilcolina (PC), podría ser una diana importante para modificar la composición de ácidos grasos del aceite de semilla, ya que su eficiencia en dicha transferencia puede determinar la composición general de ácidos grasos en el reservorio de acil-CoA, que proporciona sustrato para las enzimas aciltransferasas implicadas en la biosíntesis de TAG. Además, cabe destacar que la molécula de PC es sustrato de desaturasas y otras enzimas implicadas en la modificación de ácidos grasos. Al igual que la enzima LPCAT, la enzima fosfatidilcolina:diacilglicerol colinafosfotransferasa (PDCT) también tiene un papel importante en la composición de ácidos grasos de TAG, al catalizar la reacción de intercambio del grupo fosfocolina entre PC y diacilglicerol (DAG). El trabajo desarrollado durante esta tesis doctoral se centró en la caracterización bioquímica y molecular de enzimas de girasol implicadas en los intercambios y modificaciones de acilos y en la síntesis de glicerolípidos. Así, a partir de ADN de semillas de girasol, se clonaron y caracterizaron tres LPCATs, denominadas HaLPCAT1, HaLPCAT2 y HaLPCAT3 y una PDCT, denominada HaPDCT. Las secuencias aminoacídicas obtenidas se analizaron, encontrando los residuos altamente conservados en la familia proteica a la que pertenecen estas enzimas y se realizaron predicciones de localización subcelular y de dominios de transmembrana que definieron a estas enzimas como proteínas integrales de membrana localizadas en el retículo endoplásmico. Además, se analizaron sus perfiles de expresión en distintos tejidos de girasol y las enzimas fueron expresadas en Saccharomyces cerevisiae y caracterizadas bioquímicamente, estudiando sus especificidades por distintos substratos. También se realizaron interesantes trabajos sobre el efecto de la expresión de estos genes en los lípidos y en el conjunto de acil-CoAs de levadura incluyendo, además, estudios que implicaban la coexpresión del gen CsFAD2 que codifica para una desaturasa de Camelina sativa. Las enzimas LPCAT se expresaron también en Arabidopsis thaliana pudiendo confirmar que estas eran activas en la planta

Assessment of Food Sources and the Intake of the Colourless Carotenoids Phytoene and Phytofluene in Spain.

Phytoene (PT) and phytofluene (PTF), colorless carotenoids, have largely been ignored in food science studies, food technology, and nutrition. However, they are present in commonly consumed foods and may have health-promotion effects and possible uses as cosmetics. The goal of this study is to assess the most important food sources of PT and PTF and their dietary intakes in a representative sample of the adult Spanish population. A total of 62 food samples were analyzed (58 fruit and vegetables; seven items with different varieties/color) and carotenoid data of four foods (three fruits and one processed food) were compiled. PT concentration was higher than that of PTF in all the foods analyzed. The highest PT content was found in carrot, apricot, commercial tomato juice, and orange (7.3, 2.8, 2.0, and 1.1 mg/100 g, respectively). The highest PTF level was detected in carrots, commercial tomato sauce and canned tomato, apricot, and orange juice (1.7, 1.2, 1.0, 0.6, and 0.04 mg/100 g, respectively). The daily intakes of PT and PTF were 1.89 and 0.47 mg/person/day, respectively. The major contributors to the dietary intake of PT (98%) and PTF (73%) were: carrot, tomato, orange/orange juice, apricot, and watermelon. PT and PTF are mainly supplied by vegetables (81% and 69%, respectively). Considering the color of the edible part of the foods analyzed (fruit, vegetables, sauces, and beverages), the major contributor to the daily intake of PT and PTF (about 98%) were of red/orange color.post-print1287 K

Functional Characterization of Lysophosphatidylcholine: Acyl-CoA Acyltransferase Genes From Sunflower (Helianthus annuus L.)

Lysophosphatidylcholine acyltransferase (LPCAT, EC 2.3.1.23) is an evolutionarily conserved key enzyme in the Lands cycle that catalyzes acylation of lysophosphatidylcholine (LPC) to produce phosphatidylcholine (PC), the main phospholipid in cellular membranes. In this study, three LPCAT genes from sunflower were identified and the corresponding proteins characterized. These HaLPCAT genes encoded functionally active enzymes that were able to complement a deficient yeast mutant. Moreover, enzymatic assays were carried out using microsomal preparations of the yeast cells. When acyl specificities were measured in the forward reaction, these enzymes exhibited a substrate preference for unsaturated acyl-CoAs, especially for linolenoyl-CoA, while in the reverse reaction, linoleoyl or linolenoyl acyl groups were transferred from PC to acyl-CoA to a similar extent. Expression levels of LPCAT genes were studied revealing distinct tissue-specific expression patterns. In summary, this study suggests that the combined forward and reverse reactions catalyzed by sunflower LPCATs facilitate acyl-exchange between the sn-2 position of PC and the acyl-CoA pool. Sunflower LPCATs displayed different characteristics, which could point to different functionalities, favoring the enrichment of seed triacylglycerols (TAGs) with polyunsaturated fatty acid (PUFA)España, AEI and FEDER Project AGL2017- 83449-R. R

Carotenoides en agroalimentación y salud

Los carotenoides son compuestos especiales; si bien es común referirse a ellos como pigmentos, lo cierto es que son compuestos de gran versatilidad e importancia en la naturaleza. Más específicamente, son de gran interés en agroalimentación y salud. Así, por ejemplo, son pigmentos naturales y por lo tanto tienen un importante papel en la elección de alimentos por parte de los consumidores. Asimismo, algunos de ellos son precursores de la vitamina A. Sin embargo, que cada vez exista más interés en los carotenoides en este contexto se debe en gran parte a muchos estudios de distinta naturaleza que indican que pueden proporcionar beneficios para la salud. Su interés en alimentación funcional es por lo tanto indudable. En este libro se refleja la experiencia en carotenoides de un gran número de profesionales de la región iberoamericana. En conjunto, se ofrece una visión general de la investigación sobre estos compuestos en agroalimentación y salud. Los autores son miembros de la red IBERCAROT (http://carotenoides.us.es), que tiene entre sus objetivos conformar una red estable y funcional de profesionales que aúnen esfuerzos en pos de identificar nuevas fuentes de carotenoides de interés nutricional, mejorar su producción y aumentar el valor de los productos que los contengan

Investigación en color y calidad de alimentos

En esta ponencia se pretende presentar a los alumnos de la Escuela Politécnica Superior, las líneas de investigación del grupo Color y Calidad de Alimentos de la Universidad de Sevilla (AGR225, PAIDI) y las posibilidades de realizar Trabajos postdoctorales o continuar las salidas profesionales en el campo de industrias alimentarias.This paper tries to introduce to the student of Polytechnic School, the research lines of Color and Food Quality Group of the University of Seville (AGR225, PAIDI), and the possibilities of carrying out postdoctoral works or continuing the career in the field of food industries

A comprehensive review on the colorless carotenoids phytoene and phytofluene

Carotenoids and their derivatives are versatile isoprenoids involved in many varied actions, hence their importance in the agri-food industry, nutrition, health and other fields. All carotenoids are derived from the colorless carotenes phytoene and phytofluene, which are oddities among carotenoids due to their distinct chemical structure. They occur together with lycopene in tomato and other lycopene-containing foods. Furthermore, they are also present in frequently consumed products like oranges and carrots, among others. The intake of phytoene plus phytofluene has been shown to be higher than that of lycopene and other carotenoids in Luxembourg. This is likely to be common in other countries. However, they are not included in food carotenoid databases, hence they have not been linked to health benefits in epidemiological studies. Interestingly, there are evidences in vitro, animal models and humans indicating that they may provide health benefits. In this sense, the study of these colorless carotenes in the context of food science, nutrition and health should be further encouraged. In this work, we review much of the existing knowledge concerning their chemical characteristics, physico-chemical properties, analysis, distribution in foods, bioavailability and likely biological activities

Screening for Innovative Sources of Carotenoids and Phenolic Antioxidants among Flowers

Flowers have been used for centuries in decoration and traditional medicine, and as components of dishes. In this study, carotenoids and phenolics from 125 flowers were determined by liquid chromatography (RRLC and UHPLC). After comparing four different extractants, the carotenoids were extracted with acetone: methanol (2:1), which led to a recovery of 83%. The phenolic compounds were extracted with 0.1% acidified methanol. The petals of the edible flowers Renealmia alpinia and Lantana camara showed the highest values of theoretical vitamin A activity expressed as retinol activity equivalents (RAE), i.e., 19.1 and 4.1 RAE/g fresh weight, respectively. The sample with the highest total phenolic contents was Punica granatum orange (146.7 mg/g dry weight). It was concluded that in most cases, flowers with high carotenoid contents did not contain high phenolic content and vice versa. The results of this study can help to develop innovative concepts and products for the industry.Ministerio de Economía y Competitividad AGL2012-37610, BIO2015-71703-REDT, BIO2017-90877-RED

Screening for innovative sources of carotenoids and phenolic antioxidants among flowers

23 páginas.- 5 figuras.- 9 tablas.- 47 referencias.Flowers have been used for centuries in decoration and traditional medicine, and as components of dishes. In this study, carotenoids and phenolics from 125 flowers were determined by liquid chromatography (RRLC and UHPLC). After comparing four different extractants, the carotenoids were extracted with acetone: methanol (2:1), which led to a recovery of 83%. The phenolic compounds were extracted with 0.1% acidified methanol. The petals of the edible flowers Renealmia alpinia and Lantana camara showed the highest values of theoretical vitamin A activity expressed as retinol activity equivalents (RAE), i.e., 19.1 and 4.1 RAE/g fresh weight, respectively. The sample with the highest total phenolic contents was Punica granatum orange (146.7 mg/g dry weight). It was concluded that in most cases, flowers with high carotenoid contents did not contain high phenolic content and vice versa. The results of this study can help to develop innovative concepts and products for the industry. © 2021 by the authors.This research was funded by SENESCYT-Ecuador; the Corporación Ecuatoriana para el Desarrollo de la Investigación y Academia (CEDIA); the Spanish State Secretariat of Research,Development and Innovation (Ministry of Economy and Competitiveness, project ref. AGL2012-37610, co-funded by FEDER), E.C.-C., D.H., A.B., C.S.; the Ibero-American Programme for Science, Technology and Development (CYTED, http://www.cyted.org) for the funding of the IBERCAROT network (http://carotenoides.us.es/ref.112RT445); the Carotenoid Network: from microbial and plants to food and health (BIO2015-71703-REDT); and CaRed: Red española de carotenoides (BIO2017-90877-REDT), funded by the Spanish Ministry of Economy and Competitiveness.Peer reviewe