– Des scientifiques utilisent l’inule visqueuse, une plante silvestre qui pousse dans la Méditerranée, pour obtenir des médicaments anti-cancérigènes

Un groupe de scientifiques de l’Université de Grenade, appartenant au département de Chimie Organique et à l’Institut de Biotechnologie, ont découvert que la plante appelée Dittrichia viscosa, connue vulgairement comme inule visqueuse, peut servir pour obtenir des inhibiteurs de la vasodilatation neurogénique, ce qui pourrait bien être considéré comme un grand pas dans le traitement contre la migraine et le cancer.

La recherche a été réalisée, sous la direction des professeurs María del Mar Herrador et Alejandro Fernández Barrero, et par la chercheuse Julieta Verónica Catalán, professeure assistante de l’Université Nationale de Tucumán (Argentine) et chercheuse à l’Université de Grenade, grâce à un projet financé par l’Union Européenne à travers le Programme Alban et le Ministère des Sciences et de Technologie dEspagne. Julieta Verónica a utilisé l’inule visqueuse, une plante très abondante dans tout l’arc méditerranéen, pour mettre à point une méthode d’extraction et de purification d’un produit naturel connu sous le nom d’acide ilicique.

Un prometteur antiangiogénique
Cet acide a été utilisé comme matériel de départ pour développer une méthode de synthèse chimique efficace et d’utilité industrielle pour les médicaments actifs &-eudesmol (agent contre la migraine) et beta-eudesmol, qui inhibe “in vivo” sélectivement la prolifération des cellules endothéliales en constituant un prometteur antiangiogénique.

Les chercheurs grenadins ont fait, aussi, une autre grande découverte : ils ont employé le composant germacrone, qui est obtenu d’une plante appelée Baccharis latifolia qui pousse dans les Andes boliviennes, dans une synthèse chimique nouvelle de l’anti-tumoral béta-élémène. Ce produit naturel sert pour inhiber sélectivement les cellules endothéliales cérébrovasculaires et a donné de bons résultats comme agent anti-cancérigène pour les tumeurs de cerveau et de métastase dans le cerveau du cancer de poumon en freinant sa croissance. En plus, il a été démontré qu’il induit à l’apoptose et provoque la récession de la différentiation cellulaire et l’inhibition de métastase néoplastique, et peut être utilisé en chimiothérapie des néoplasmes dans le poumon, le côlon, l’estomac, le cerveau, etc. Il existe différentes formulations brevetées pour son seul usage ou accompagnées d’autres agents tumoraux comme le taxol, 5-FU ou dérivés du cis-platine.
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– New mineralogical techniques contribute to prevent national heritage damage

Humidity, environmental pollution, cleaning with aggressive products for the chemical composition of the rock, etc give rise to the appearance of salts which cause stone decomposition, paint coats detachment, dust accumulation, etc.

The treatments used up to now to deal with the problem have been directed, almost exclusively, to preserve the beauty of the affected monument, assuming, with an almost fatalist attitude, that the damage will go on as an effect of passing of time. European experts joint in the SALTCONTROL project have collaborated in a new work line to deal with the problem: Blocking inside the stone the mineral salt crystallization process that ends up destroying it.

One of the works carried out in the framework of SALTCONTROL is the doctoral thesis “Prevención del daño debido a cristalización de sales en el patrimonio histórico construido mediante el uso de inhibidores de cristalización” (Damage prevention due to salt crystallization in national heritage through the use of crystallization inhibitors), read by Encarnación María Ruiz Agudo, under the supervision of Prof Carlos Manuel Rodríguez Navarro; as well as several papers published by scientific journals such as Journal of Physical Chemistry, Environmental Geology, Scanning y Journal of the Japanese Association for Crystal Growth.

According to Ruiz Agudo ( Centro Andaluz del Medio Ambiente– Department of Mineralogy and Petrology of the University of Granada) “ornamental porous materials’ damage due to salt attack is one of the most aggressive alteration mechanisms that affect constructed heritage. In the last decades, we have developed different methods to prevent or reduce the damage due to salt crystallization in ornamental rock pores, almost all with little success”.

The thesis’s research line and the above mentioned papers have followed the recent techniques that intend to use additives to modify the crystallization process and prevent or reduce the damage produced in the rock. Up to now, most of the works in this field have assessed the efficiency of these treatments in slightly soluble salts, such as calcium and barium sulphates. The thesis “has proved the effectiveness of this type of treatment in highly soluble salts, such as sodium and magnesium sulphates, as well as sodium nitrate, which can usually be found in historic buildings”.

Applied science

The research work has been applied to the case of the effects of these treatments in the rock extracted in Santa Pudia’s quarries (Escúzar,-Granada), used in the construction of Renaissance buildings in Granada such as the Monastery of San Jerónimo, the Cathedral or the Royal Chapel. These buildings show strong alteration phenomenon due to crystallization in sodium sulphate, magnesium and sodium nitrate.

The work has conducted to the carrying out of salt crystallization tests in laboratory, which simulate alteration processes due to salt crystallization in the bases on historic buildings’ walls. “Later –says Ruiz Agudo-, we prepared a method for the implementation of the treatment developed in practical cases of ornamental stone materials conservation. Finally, in a last phase of development of the research project, we applied such treatment in pilot areas on the Monastery of San Jerónimo (Granada), where there had been important problems due to salt crystallization”.

The final result of the research work proposes the application of low-cost additives, which have proved to be very effective in the fight against the problems of ornamental porous materials. On the other hand, the research work “involves a methodology to deal with the study of damage caused by salts and the selection of the most adequate type of additive for a specific substrate and type of salt. The object of the methodology is the study of the problem in situ, in order to carry out laboratory tests that allow to select the concentration, pH and the most appropriate application method and finally to go back to the building to test the treatment in pilot areas, which permits to guarantee the success in the application of salt crystallization inhibitors inside stony materials, as we have proved in San Jerónimo”.

SALTCONTROL

The research work is part of the SALTCONTROL project, financed by the 6th framework Programme of the EU for the period 2004-2007. Together with the University of Granada, other organisms have participated in the project: the University of Münster (Germany), the University of Gant (Belgium), the University College of London, the University of Patras in Greece, the Technical University of Prague, the Architecture Conservation Centre TNO of Holland, the Andalusian Institute of National Heritage and the Technical University of Eindhoven.

SALTCONTROL’s results have been successfully applied in the Monastery of San Jerónimo (Granada-Spain) and the Fortress of Teresina (Prague, Czech Republic).

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– Experts prove the geochemical origin of part of the CO2 emissions in semiarid climates

The implementation of the Kyoto Protocol has raised, among other pressing matters, the need of getting to know the annual levels of carbon in different earth’s ecosystems. Scientists connected with the CEAMA-Andalusian Centre for the Environment (University of Granada-Andalusian Council) are studying these levels in semiarid Mediterranean scrubland, situated in Eastern Andalusia, whose results are comparable to wide regions of the world.

These researchers have analysed for the first time the CO2 level in carbonated semiarid systems. The interest of the work lies in the knowledge of the CO2 production processes and their absorption and in the conservation of one of the richest ecosystems of Spain.

One of the most recent studied on the subject is the doctoral thesis “CO2 interchanges between atmosphere and karst ecosystems: Applicability of the commonly applied techniques”, read by Penélope Serrano Ortiz and led by Doctors Andrew S. Kowalski and Lucas Alados Arboledas.

The work, supported by the “Carbon and water balance in Mediterranean thicket ecosystems in Andalusia: Effect of the climatic change” project, has permitted to quantify and identify the processes involved in carbon annual balance in a semiarid carbonated substrate ecosystem, situated in Sierra de Gádor (Almeria). After three years of observation of this ecosystem (2004-2006), through the use of the most advanced techniques (attached photo), have permitted to estimate the annual carbon balance. The carbon balance of this type of ecosystem has been checked for the first time, revealing that it acts as a CO2 drain which assimilates approximately 25 g C m-2 a year (between 10 and 20 times lower than arable land and tree ecosystems respectively).

Extreme climate

What is the meaning of this in an area characterized by a scrubland vegetation and a dry climate? Up to now, when it came to devise measures to prevent climatic change, they used to value tree ecosystems especially; that is the origin of the emphasis made in the reforestation and forestation of neglected agricultural land. But little attention had been paid to other ecosystems, such as the thicket ecosystem object of this study, which represents more than half the forest area of Andalusia (where a great part of the biological diversity of the Mediterranean ecosystems gathers together).

In that respect, besides defining the CO2 assimilation capacity of the studied thicket area, Serrano’s thesis has proved how rain distribution conditions the functional nature of the studied ecosystem and how the duration of the drought period and, therefore, the water content, determinates the duration of the CO2 geochemical emissions, through soil ventilation.

It proves that CO2 production is not only related to vegetation, but also to geochemical emissions which increase in dry seasons.

“The hypothesis formulated in this work -says Serrano- is that the emissions are a consequence of a ventilation phenomenon of the carbonated system’s macro-pores, which appear to be connected with wind speed. In this line, certain studies on degasification phenomenon in caves and turbulent CO2 interchanges with the atmosphere, carried out by Sergio Sánchez Moral and Soledad Cuezva Robleño (Spanish Museum of Natural Sciences, CSIC) in the Altamira Cave, endorse the theory of the existence of CO2 geochemical flows in ecosystems situated in karst substrate”.

Politics and ecology

CO2 is one of the main greenhouse gases which contributes to the rise of earth’s temperature. Serrano Ortiz’s study is the first one focused on carbonated semiarid ecosystems and has proved that they act as CO2 drains, due to the action of the thickets, and as CO2 geochemical generators in dry periods (especially worrying if we reach the temperature rise predicted by climatic change models).

His work provides data of C (carbon) flows in key ecosystems for biodiversity conservation, as well as for the negotiations related to CO2 emissions.
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– Fraud attempt in a paternity test modifies action protocol in DNA tests

Researchers from all over the world have been carrying out paternity tests regularly. Samples are usually collected from mouth and saliva cells to carry out the DNA analysis.

The team of Dr José Antonio Lorente Acosta (director of the Laboratory of Genetic Identification of the University of Granada) carries out these forensic studies commissioned by the court in cases of paternity tests, for the identification of possible criminals or to carry out DNA databases (such as in the case of missing relatives).

The detection of a fraud attempts in a paternity test case in 2007 is changing the action protocol of forensic teams in similar cases. The team of Dr Lorente encountered a strange case: “the saliva analysis (epithelial cells from the interior of mouth) collected from a person undergoing a paternity test gave an incongruous result, a DNA which could not come from the man who had carried out the test”.

The revision of the case revealed that they had followed the usual procedure: the suspect washed his mouth and after that they took the samples with a cotton swab. “After repeating the analysis, there was an only one possible conclusion: In the mouth of that man there was DNA from two different persons”. After dismissing other possibilities, the question was: how was it possible? “We arranged to meet the person in question, we showed him the result and we explained him that we suspected that he had manipulated the samples which, as it was a trial in judicial investigation, could bring him serious consequences. Faced wit the evidence, he admitted that, shortly before the sample taking, he put into his mouth some saliva he kept in a little container”.

It was an attempt to evade the responsibility in a case of extramarital paternity demand, and “he admitted that, when he mixed his saliva with someone else’s, he attempted to mislead the experts in forensic genetics and, through them, the judge. After repeating the test it was revealed (with a probability of more than 99, 999998%) that he was the biological father in that case of judicial investigation”.

Consequences
The referred case gains a special importance as this is the first time it has been described that someone has mixed two types of saliva in order to alter a DNA test; manipulation attempts in blood samples had been described before (with transfusions before the sample taking, for example).

“We must highlight –points out Lorente- that the alteration of DNA tests is almost impossible without forensic experts realizing it, but this case aroused the interest of the scientific community after its publication in the journal of the American Academy of Forensic Sciences. The reason is obvious: It raises the need of adopting special measures to prevent experts’ error leading to crime or fraud or lack of punishment. From this publication, many protocols of saliva taking for forensic analysis (cases of paternity, crime suspects, and DNA databases) include the obligation for saliva donors to wash their mouth out with water before a witness, just before he places the swab in his mouth to collect saliva samples”.

This case was studied by FBI experts (USA), interested in preventing possible manipulation attempts of the tests, and one of them, Dr Bruce Budowle, is co-author of the work.
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– Des scientifiques ont rassemblé les données de températures du XXème siècle en Espagne comme preuve du Changement Climatique

Cette recherche est le premier pas pour affirmer l’existence d’un changement des températures. Son principal objectif est de “détecter les signes du Changement Climatique à travers les températures en Espagne”, a expliqué à SINC (Service d’Information et de Nouvelles Scientifiques) le chercheur du département de Physique Appliquée de l’Université de Grenade et auteur principal, Matthias Staudt.

La compilation des séries de températures maximales et minimales de chaque mois depuis la fin du XIXème siècle jusqu’au début du XXIème siècle n’a pas été une tâche facile. Les données, qui ont été recueillies de 45 observatoires espagnols, n’ont pas été dans tous les cas “homogènes”. Dans la climatologie, une série de données (série temporaire) est considérée homogènes quand leur contenu reflète exclusivement l’évolution climatique (c’est-à-dire, quand les divers facteurs indésirables sont absents). Par conséquent, le travail des chercheurs a consisté principalement à éliminer la “contamination” inhomogène dans les données.

Traiter la qualité des données – qui ont été publiées au novembre dernier dans la revue « International Journal of Climatology » – devient, selon le scientifique, «la meilleure méthode pour croire aux résultats finaux». «La préparation technique est indispensable pour faire le pas et faire des recherches sur l’augmentation des températures à un niveau statistique indiscutable», a ajouté.

Homogénéisation des données
Changer un thermomètre calibré de manière différente est un des facteurs pour lesquels les données sur les températures ont tendance à présenter des incohérences. En plus, les différentes interprétations de lecture d’un être humain ou les fréquents changements de lieu des observatoires (changement de milieu urbain à l’aéroport, changement d’altitude, etc.) sont des problèmes auxquels l’équipe de scientifiques en a tenu compte.

«En changeant de lieu le thermomètre, sans signaler ce fait, donne un résultat très bizarre que 50 ans plus tard personne n’est capable d’expliquer», a indiqué Staudt. S’ajoute à cela les erreurs humaines de type typographique dont les données sont “inhomogènes”.

Les scientifiques ont travaillé durant cinq années pour chercher à savoir, évaluer et réparer les séries de données. «Pour qu’elles soient les plus fiables possibles et pour qu’elles ne soient pas un prétexte pour les plus réticents à admettre le Changement Climatique », a argumenté le chercheur. Même s’il admet ne pas être arrivé à des “certitudes absolues”, un critère de “normalité” a été établi dans le comportement des températures. « Avec une grande probabilité, une baisse qualitative de sept degrés d’avril au mai n’est pas normal, alors que dans tous les cas ça devrait normalement être une hausse».

En raison de l’ensemble des problèmes d’homogénéité précisés dans les séries mensuelles analysées, les chercheurs se sont imposé un critère de “détection des inhomogénéités” très strictes. Malgré cela, l’erreur instrumentale dans une mesure de température est de l’ordre de 0,1ºC et l’erreur d’une différence entre les données, antérieurement traités avec la méthode d’homogénéisation, s’élève à l’ordre de 0,4ºC. Cette erreur n’est pas insignifiante, mais en tout «considérablement mineur que dans les données en brut».

Pour arriver à des conclusions qui confirment le changement climatique en Espagne, à un haut niveau de confiance, ce travail technique représente un « effort nécessaire et évident ». Staudt a déclaré que «les résultats sur le Changement Climatique qui ont été obtenus ne sont pas nouveaux, mais confirmeront ce qu’on savait (presque) déjà».

M, Staudt, M.J. Esteban-Parra, Y. Castro-Diez. “Homogenization of long-term monthly Spanish temperatura data”, International Journal of Climatology 27 (13) : 1809-1823 Nov. 15 2007.

Seulement pour les médias : Université de Grenade amarin@ugr.es. Tél. (+34) 958 24 29 35
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