Composición del aceite de la semilla del pistacho (Pistacia vera): efectos de la situación geográfica y de la variedad

This study was aimed at characterizing four Tunisian pistachio cultivations (Pistacia vera) from the Mateur (North), Nabeul (North-East), Kairouan (Middle) and Sfax (Middle- East) regions and two varieties, Mateur and Ohadi, considering fatty acid composition and main lipid class contents (polar lipids, diacylglycerols, triacylglycerols and free fatty acids) in ripe seeds. Lipid classes were separated using thin layer chromatography, and fatty acid methyl esters (FAMEs) were analyzed by gas chromatography. Oleic acid (C18:1 Δ9) was the major fatty acid for all samples; those of the Mateur region (the northern region) differed significantly with the lowest content in C18:1 (54.2 % of total fatty acids) and the highest in C18:2 (24.1 %). The total amount of fatty acids (TFA) in the seeds of Ohadi variety was significantly lower than that of the Mateur variety from the Sfax region. Triacylglycerols were most abundant in pistachio seeds from Nabeul (98.5% of total glycerolipids).Este estudio tiene como objetivo caracterizar cuatro cultivos de pistacho (Pistacia vera) de Túnez, de las regiones de Mateur (Norte), Nabeul (Nordeste), Kairouan (Centro) y Sfax (Centro-Este) y dos variedades, Mateur and Ohadi, considerando la composición en ácidos grasos y de lípidos mayoritarios (lípidos polares, diglicéridos, triglicéridos y ácidos grasos libres) de semillas maduras. Los lípidos se separaron mediante cromatografía en capa fina, y los ésteres metílicos de los ácidos grasos (FAMEs) se analizaron por cromatografía de gases. El ácido oleico (C18:1 Δ9) fue el mayoritario en todas las muestras; las de la región de Mateur (Norte) fueron significativamente distintas, presentando el contenido más bajo de C18:1 (54.2 % del total de ácidos grasos) y más alto de C18:2 (24.1 %). La cantidad total de ácidos grasos (TFA) en las semillas de la variedad Ohadi fue significativamente más bajo que el de la variedad Mateur de la región de Sfax. Los triglicéridos fueron el componente más importante en la semillas de pistacho de Nabeul (98.5% del total de glicerolípidos)

Control of Fusarium Wilt of Tomato Caused by Fusarium oxysporum F. Sp. Radicis-Lycopersici Using Mixture of Vegetable and Posidonia oceanica Compost

A compost of vegetable waste and Posidonia oceanica mixture (70 : 30% vol : vol) was tested in vitro and in vivo for its efficacy against Fusarium oxysporum f.sp radicis-lycopersici (Forl), the causal agent of Fusarium wilt of Tomato (Lycopersicon esculentum cv. chourouk).The incorporation of non-sterilized VPC in the culture medium showed potent antifungal activity against Forl and complete inhibition of mycelium growth was observed for all the tested compost rates (0.5, 1, 2, 4, 6, 8, 10, 15 and 20%). However, only the highest rates (15 and 20%) of a sterilized suspension of VPC were effective in preventing mycelial growth. Nine indigenous bacterial strains isolated from VPC exhibited antagonism against Forl. Based on 16S rDNA sequence analysis, the isolates were assigned to Bacillus sphaericus (B12 and BS2), Pseudomonas putida PPS7 and Burkholderia gladioli BuC16. Under green house condition, seed inoculation by B12, BS2, PP7 and BuC16 strains protected significantly tomato against Fusarium oxysporum f.sp radicis-lycopersici (Forl) attacks

Photochemistry of organic molecules in the Solar System: experimental studies outside the International Space Station. The cases of glycine, and nucleobases

Solar UV radiation is a major source of energy for initiating chemical evolution towards complex organic structures, but it can also photo-dissociate even the most complex molecules. Thus, solar UV can erase the organic traces of past life at the surface of planets, such as Mars, destroy organic molecules present on meteorites and micrometeorites, influence the production of distributed sources in comets or initiate chemistry in Titan's atmosphere. In the interstellar medium, the UV radiation field emitted by stars in the galaxy is also responsible for the chemical evolution and the extraordinary diversity of organic molecules detected. PSS (Photochemistry on the Space Station) was a Low Earth Orbit (LEO) experiment, implemented from mid-2014 to early 2016 on the EXPOSE-R2 platform outside the International Space Station. Its goal was to improve our knowledge about the chemical nature and evolution of organic molecules with astrobiological implications in space environments. It was a new step in a series of experiments conducted outside the MIR space station, in the ESA BIOPAN and previous EXPOSE facilities. In PSS, both vented and sealed cells were used allowing exposure of both solid and gaseous samples. Five kinds of experiments was carried out exposing molecules related to different environmental factors of astrobiological significance: the interstellar medium, comets & meteorites, Titan, Mars, as well as a set of samples to test the stability of biochips in space. In this talk we will describe the PSS experiment and focus on some results related to the stability of some prebioticaly relevant compounds such as glycine, the simplest amino acid, and nucleobases such as uracil, guanine and adenine. These molecules were both exposed in Low Earth Orbit and studied in the laboratory in order to derive their photochemical lifetime if they are ejected from comets on dust particles and orbit around the Sun before reaching the Earth as micrometeorites. The results can lead to better understand the contribution of cometary particles in the establishment of an organic reservoir on primitive Earth