Efecto del fotoperiodo en la terminación de la diapausa de larvas de los taladros del maíz, Sesamia nonagrioides y Ostrinia nubilalis, desarrolladas en distintas variedades de maíz transgénico y sus isogénicas correspondientes

La creciente implantación de maíz transgénico en España está ocasionando cambios importantes en las poblaciones de taladros de maíz y en su ecofisiología, cambios que están por estudiar. En el evento de maíz transgénico Bt 176, hoy en día no autorizado, la concentración de proteína de Bacillus thuringiensis decrecía en el maíz senescente de forma que en otoño se podían encontrar en campos con este evento alguna larva de taladros. La implantación de maíz con el evento MON 810 sugirió la posibilidad de estudiar la posible supervivencia de larvas en maíz senescente y algunos aspectos de la diapausa de estas larvas. Para ello se infestaron 6 variedades de maíz, una con el evento Bt 176, dos con el evento MON 810 y las tres isogénicas correspondientes, con larvas neonatas de Sesamia nonagrioides (Lefébvre), confiando en una infestación natural de Ostrinia nubilalis (Hübner). Las larvas de S. nonagrioides recogidas en el evento Bt176 suponían el 14% del total de larvas de esta especie muestreadas, mientras que las de O. nubilalis recogidas en el maíz Bt suponían un 25% del total de esta especie. Sin embargo en las variedades con el evento MON 810 apenas se recogieron un 0,25% y un 1,9% de larvas de S. nonagrioides y O. nubilalis respectivamente. Las larvas recogidas en el evento Bt 176 no mostraron diferencias en su intensidad de diapausa con las recogidas en las isogénicas correspondientes. El efecto del fotoperiodo en la terminación de la diapausa fue diferente en ambas especies: mientras que el fotoperiodo largo aceleraba la terminación de diapausa en S. nonagrioides pero no en O. nubilalis pareciendo tener un efecto más pronunciado la oscuridad completa. El parasitismo por parte de Lydella thompsoni (Herting) fue del 5% para el total de larvas de O. nubilalis mientras que para el total de larvas de S. nonagrioides fue del 0,4% lo que indica la preferencia de esta taquínido por el pirálido.

Identification of carotenoids using mass spectrometry

The present review compiles positive MS fragmentation data of selected carotenoids obtained using various ionization techniques and matrices. In addition, new experimental data from the analysis of carotenoids in transgenic maize and rice callus are provided. Several carotenes and oxygen-functionalized carotenoids containing epoxy, hydroxyl, and ketone groups were ionized by atmospheric pressure chemical ionization (APCI)-tandem mass spectrometry (MS/MS) in positive ion mode. Thus, on the basis of the information obtained from the literature and our own experiments, we identified characteristic carotenoid ions that can be associated to functional groups in the structures of these compounds. In addition, pigments with a very similar structure were differentiated through comparison of the intensities of their fragments. The data provide a basis for the structural elucidation of carotenoids by mass spectrometry (MS).

Ultrastructural characterisation of the cell wall of Arabidopsis thaliana transgenic plants

The plant cell wall is a strong fibrillar network that gives each cell its stable shape. It is constituted by a network of cellulose microfibrils embedded in a matrix of polysaccharides, such as xyloglucans. To enlarge, cells selectively loosen this network. Moreover, there is a pectin-rich intercellular material, the middle lamella, cementing together the walls of adjacent plant cells. Xyloglucan endotransglucosylase/hydrolases (XTHs) are a group of enzymes involved in the reorganisation of the cellulose-xyloglucan framework by catalysing cleavage and re-ligation of the xyloglucan chains in the plant cell wall, and are considered cell wall loosening agents. In the laboratory, it has been isolated and characterised a XTH gene, ZmXTH1, from an elongation root cDNA library of maize. To address the cellular function of ZmXTH1, transgenic Arabidopsis thaliana plants over-expressing ZmXTH1 (under the control of the CaMV35S promoter) were generated. The aim of the work performed was therefore the characterisation of these transgenic plants at the ultrastructural level, by transmission electron microscopy (TEM).The detailed cellular phenotype of transgenic plants was investigated by comparing ultra-thin transverse sections of basal stem of 5-weeks old plants of wild type (Col 0) and 35S-ZmXTH1 Arabidopsis plants. Transgenic plants show modifications in the cell walls, particularly a thicker middle lamella layer with respect the wild type plants, supporting the idea that the overexpression of ZmXTH1 could imply a pronounced wall-loosening. In sum, the work carried out reinforces the idea that ZmXTH1 is involved in the cell wall loosening process in maize.  

Ninety-day oral toxicity studies on two genetically modified maize MON810 varieties in Wistar Han RCC rats (EU 7th Framework Programme project GRACE)

The GMO Risk Assessment and Communication of Evidence (GRACE; www.grace-fp7.eu) project is funded by the European Commission within the 7th Framework Programme. A key objective of GRACE is to conduct 90-day animal feeding trials, animal studies with an extended time frame as well as analytical, in vitro and in silico studies on genetically modified (GM) maize in order to comparatively evaluate their use in GM plant risk assessment. In the present study, the results of two 90-day feeding trials with two different GM maize MON810 varieties, their near-isogenic non-GM varieties and four additional conventional maize varieties are presented. The feeding trials were performed by taking into account the guidance for such studies published by the EFSA Scientific Committee in 2011 and the OECD Test Guideline 408. The results obtained show that the MON810 maize at a level of up to 33 % in the diet did not induce adverse effects in male and female Wistar Han RCC rats after subchronic exposure, independently of the two different genetic backgrounds of the event

Aspectos metabólicos y multivitamínicos del maíz

La deficiencia de vitamina A causa 2.2 millones de muertes al año. Por tanto, investigadores intentan elevar el contenido de β-caroteno y otros carotenoides en cereales mediante la ingeniería genética. Mi trabajo consistió en analizar carotenoides en maíz y callos de arroz transgénico con el fin de indentificar y cuantificar estos pigmentos y además analizar la ruta metabólica de los mismos. Por tal motivo, desarrollaré una técnica analítica por HPLC y UHPLC que me permitió separar la mezcla de carotenoides. Estas moléculas se detectaton utilizando un detector de arreglo de diodos y masas. Con éste último se probaron distintas técnicas de ionización (ESI, APCI y APPI) para encontrar la mejor técnica que ionizara carotenos y xantófilas. Además se hallaron transiciones para identificar a cada uno de los carotenoides. Para mostrar la confiabilidad del método analítico, realicé la validación del mismo y determiné factores importantes que influyen en el análisis de carotenoides, como por ejemplo, su estabilidad química. Para analizar la ruta metabólica de los carotenoides, se realizaron distintos experimentos, entre ellos, introducir distintas combinaciones de genes en el maíz y arroz que permitieran entender cuáles eran las enzimas importantes que permitían la acumulación de carotenoides. También se analizó la biosíntesis de carotenoides a distintas etapas del desarrollo de la semilla de maíz, desde los 15 días después de la polinización (DAP) hasta los 60 DAP y su estabilidad química a lo largo de todo este período. Finalmente, se profundizó en la identificación de nuevos carotenoides encontrados en las muestras, como los oxo-carotenoides (utilizados en la industria como colorantes). Para llevar acabo su identificación, se realizaron pruebas químicas, se determinaron sus espectros visibles y sus fragmentos por masas.   

Analysis of the transcriptional activity of endogenous NFAT5 in primary cells using transgenic NFAT-luciferase reporter mice

Background: The transcription factor NFAT5/TonEBP regulates the response of mammalian cells to hypertonicity. However, little is known about the physiopathologic tonicity thresholds that trigger its transcriptional activity in primary cells. Wilkins et al. recently developed a transgenic mouse carrying a luciferase reporter (9xNFAT-Luc) driven by a cluster of NFAT sites, that was activated by calcineurin-dependent NFATc proteins. Since the NFAT site of this reporter was very similar to an optimal NFAT5 site, we tested whether this reporter could detect the activation of NFAT5 in transgenic cells.Results: The 9xNFAT-Luc reporter was activated by hypertonicity in an NFAT5-dependent manner in different types of non-transformed transgenic cells: lymphocytes, macrophages and fibroblasts. Activation of this reporter by the phorbol ester PMA plus ionomycin was independent of NFAT5 and mediated by NFATc proteins. Transcriptional activation of NFAT5 in T lymphocytes was detected at hypertonic conditions of 360–380 mOsm/kg (isotonic conditions being 300 mOsm/kg) and strongly induced at 400 mOsm/kg. Such levels have been recorded in plasma in patients with osmoregulatory disorders and in mice deficient in aquaporins and vasopressin receptor. The hypertonicity threshold required to activate NFAT5 was higher in bone marrow-derived macrophages (430 mOsm/kg) and embryonic fibroblasts (480 mOsm/kg). Activation of the 9xNFAT-Luc reporter by hypertonicity in lymphocytes was insensitive to the ERK inhibitor PD98059, partially inhibited by the PI3-kinase inhibitor wortmannin (0.5 μM) and the PKA inhibitor H89, and substantially downregulated by p38 inhibitors (SB203580 and SB202190) and by inhibition of PI3-kinase-related kinases with 25 μM LY294002. Sensitivity of the reporter to FK506 varied among cell types and was greater in primary T cells than in fibroblasts and macrophages.Conclusion: Our results indicate that NFAT5 is a sensitive responder to pathologic increases in extracellular tonicity in T lymphocytes. Activation of NFAT5 by hypertonicity in lymphocytes was mediated by a combination of signaling pathways that differed from those required in other cell types. We propose that the 9xNFAT-Luc transgenic mouse model might be useful to study the physiopathological regulation of both NFAT5 and NFATc factors in primary cells.

Traducción comentada de “Genetically Modified Organisms (GMOs): Transgenic Crops and Recombinant DNA Technology”

The purpose of this paper is to provide a translation into Spanish of a review articleabout genetically modified organisms (GMOs) entitled “Genetically ModifiedOrganisms (GMOs): Transgenic Crops and Recombinant DNA Technology” publishedby the well-known scientific journal Nature. In a world where English has become thelingua franca when it comes to transferring scientific knowledge and information, itmust be taken into account that not everyone—from scientist to the general public—hasa good enough command of English so that they can feel comfortable enough reading inthis language. Translators are consequently needed resulting from a great demand oftranslation activity into, for example, Spanish. This is the reason why the proposedSpanish translation is followed by a detailed analysis emphasizing the difficulties andproblems that characterize scientific—and also general—translation (i.e. terminology,syntax, semantics, pragmatics, and ideology), for which different approaches as how tosolve them are provided. On the basis of the analysis, it can be concluded thatexperience will be of much help to scientific translators, given that specificterminological knowledge and style requirements must always be born in mind whentranslating in this field. Moreover, this paper is intended to serve as a guide forTranslation students specializing in the field of science and the expectation is to helpthem make the right decisions when it comes to translating. However, it is clear that itcan only be thought of as an introduction that should be completed with further researchand documentation tasks in order to offer a complete reference tool: the ultimatehandbook of scientific translation.

Phenotyping maize for adaptation to drought

The need of a better adaptation of crops to drought is an issue of increasing urgency. However, enhancing the tolerance of maize has, therefore, proved to be somewhat elusive in terms of plant breeding. In that context, proper phenotyping remains as one of the main factors limiting breeding advance. Topics covered by this review include the conceptual framework for identifying secondary traits associated with yield response to drought and how to measure these secondary traits in practice.

Background, current status and future prospects of transgenic crop plant development

Les plantes transgèniques són una part integral de l’agricultura contemporània. Durant l’any 2006 més de noranta milions d’hectàrees de plantes transgèniques van ser cultivades en vint-i-un països. Des de la comercialització de la primera planta transgènica el 1996 els nivells d’adopció d’aquests cultius han augmentat anualment amb percentatges de dos dígits. El desenvolupament i la comercialització de les plantes transgèniques van lligats estretament al comerç mundial, a la globalització, a la disponibilitat de suficient menjar, a la protecció del medi ambient i del consumidor i a la propietat intel·lectual. En aquest article exposem els avenços més recents i les tendències actuals en el desenvolupament dels cultius transgènics i de la seva utilització. També ens fem ressò d’alguns assumptes no científics que s’han de solucionar abans que aquests cultius arribin al màxim del seu potencial, proporcionant una agricultura més sostenible i ecològica. Finalment, ressaltarem la importància de com les plantes transgèniques poden contribuir en la disponibilitat de menjar i en la millora de la pobresa en els països en vies de desenvolupament.

Post-market environmental monitoring of Bt maize in Spain: Non-target effects of varieties derived from the event MON810 on predatory fauna

The Spanish Government has established post-market environmental monitoring (PMEM) as mandatory for genetically modified (GM) crop varieties cultivated in Spain. In order to comply with this regulation, effects of Bt maize varieties derived from the event MON810 on the predatory fauna were monitored for two years in northeast and central Spain. The study was carried out with a randomized block design in maize fields of 3-4 ha on which the abundance of plant-dwelling predators and the activity-density of soil-dwelling predators in Bt vs. non-Bt near-isogenic varieties were compared. To this end, the plots were sampled by visual inspection of a certain number of plants and pitfall traps 6 or 7 times throughout two seasons. No significant differences in predator densities on plants were found between Bt and non-Bt varieties. In the pitfall traps, significant differences between the two types of maize were found only in Staphylinidae, in which trap catches in non-Bt maize were higher than in Bt maize in central Spain. Based on the statistical power of the assays, surrogate arthropods for PMEM purposes are proposed; Orius spp. and Araneae for visual sampling and Carabidae, Araneae, and Staphylinidae for pitfall trapping. The other predator groups recorded in the study, Nabis sp. and Coccinellidae in visual sampling and Dermaptera in pitfall trapping, gave very poor power results. To help to establish a standardized protocol for PMEM of genetically modified crops, the effect-detecting capacity with a power of 0.8 of each predator group is given.

Influence of sample processing on the analysis of carotenoids in maize

We performed a number of tests with the aim to develop an effective extraction method for the analysis of carotenoid content in maize seed. Mixtures of methanol–ethyl acetate (6:4, v/v) and methanol–tetrahydrofuran (1:1, v/v) were the most effective solvent systems for carotenoid extraction from maize endosperm under the conditions assayed. In addition, we also addressed sample preparation prior to the analysis of carotenoids by liquid chromatography (LC). The LC response of extracted carotenoids and standards in several solvents was evaluated and results were related to the degree of solubility of these pigments. Three key factors were found to be important when selecting a suitable injection solvent: compatibility between the mobile phase and injection solvent, carotenoid polarity and content in the matrix.