DNA methylation in adults and during development of the self-fertilizing mangrove rivulus, <i>Kryptolebias marmoratus</i>

In addition to genetic variation, epigenetic mechanisms such as DNA methylation might make important contributions to heritable phenotypic diversity in populations. However, it is often difficult to disentangle the contributions of genetic and epigenetic variation to phenotypic diversity. Here, we investigated global DNA methylation and mRNA expression of the methylation‐associated enzymes during embryonic development and in adult tissues of one natural isogenic lineage of mangrove rivulus fish, Kryptolebias marmoratus. Being the best‐known self‐fertilizing hermaphroditic vertebrate affords the opportunity to work with genetically identical individuals to examine, explicitly, the phenotypic effects of epigenetic variance. Using the LUminometric Methylation Assay (LUMA), we described variable global DNA methylation at CpG sites in adult tissues, which differed significantly between hermaphrodite ovotestes and male testes (79.6% and 87.2%, respectively). After fertilization, an immediate decrease in DNA methylation occurred to 15.8% in gastrula followed by re‐establishment to 70.0% by stage 26 (liver formation). Compared to zebrafish, at the same embryonic stages, this reprogramming event seems later, deeper, and longer. Furthermore, genes putatively encoding DNA methyltransferases (DNMTs), Ten‐Eleven Translocation (TET), and MeCP2 proteins showed specific regulation in adult gonad and brain, and also during early embryogenesis. Their conserved domains and expression profiles suggest that these proteins play important roles during reproduction and development. This study raises questions about mangrove rivulus’ peculiar reprogramming period in terms of epigenetic transmission and physiological adaptation of individuals to highly variable environments. In accordance with the general‐purpose genotype model, epigenetic mechanisms might allow for the expression of diverse phenotypes among genetically identical individuals. Such phenotypes might help to overcome environmental challenges, making the mangrove rivulus a valuable vertebrate model for ecological epigenetic studies. The mangrove rivulus, Kryptolebias marmoratus, is the best‐known self‐fertilizing hermaphroditic vertebrate that allows to work with genetically identical individuals to examine, explicitly, the phenotypic effects of epigenetic variance. The reprogramming event is later, more dramatic and longer than in other described vertebrates. High evolutionary conservation and expression patterns of DNMT, TET, and MeCP2 proteins in K. marmoratus suggest biological roles for each member in gametogenesis and development

STUDY OF THE ANTIOXIDANT ACTIVITY OF FLAVONOIC EXTRACT OF A MEDICINAL PLANT (CALOTROPIS PROCERA) OF AHAGGAR TAMANRASSET

Calotropis procera (family Lamiaceae) is a famous medicinal plant in the region of Hoggar Tamanrasset in southern Algeria. In this study, will have undertaken the study of the antioxidant activity of the flavonoid extract of this plant using several solvents (diethylether, ethyl acetate and N-butanol), the potential antioxidant extracts was determined on the based on their scavenging activity of the stable 1.1-Diethyl-2, hydrazylpyrryl (DPPH) free radicals. The values ​​of IC50 (mg / ml) were for the extract of 0.020 g / l, 0.014 g / l and 0.029 g / l successively for diethyl ether, ethyl acetate and N-butanol. Compared to the salts of ascorbic acid (VC) and tocopherol acid (VE) which were 0.011g / l and 0.015 g / l respectively. In addition the FRAP (Fenic antioxidant power reduction) effective acetate test on the same extract. By using VEAC (Vit E equivalent antioxidant capacity) it is found that the ethyl acetate extract has a higher reducing power than the other extracts equal to 1.115 g / l. diethyl ether 0.956g / l and n-butanol 0.987 g / l and ascorbic acid (VC) was considered a positive test with a VEAC is equal to 2.031g /

Synthesis and Characterization of ZnO Thin Film for Modeling the Effect of Its Defects on ZnO/Cu2O Solar Cell EQE

Zinc oxide (ZnO) is one of the best transparent conducting oxide (TCO) materials with a wide bandgap and good electrical and optical properties. Its low cost, nontoxicity and transparency in the optical region of the electromagnetic spectrum make it very promising candidate for solar cell applications. In this work, zinc acetate precursor was used to grow a ZnO thin film by using sol-gel spin-coating technique. The surface morphological study using scanning electron microscope (SEM) was carried out to confirm the growth pattern and crystal distribution. The optical properties, transmission (T), reflection (R), optical bandgap (Eg), refractive index (n), and extinction coefficient (k) were extracted and investigated to be used in the simulation of ZnO/Cu2O heterostructure solar cell, where ZnO thin film plays a double role: as the TCO window, as well as the emitter of the n-p junction. However, the solar cell showed weak external quantum efficiency (EQE) compared to those prepared by using zinc nitrate and diethyl zinc precursors. TCAD numerical simulation was used to clarify the origin of this weak EQE by taking into account two parameters. The first studied parameter is the root-mean-square interface roughness, σRMS, in Haze modeling approach, H, which describes how much of incident light is scattered at the interface. The second studied parameter is the density of defects in the ZnO bulk with continuous distribution of states in its bandgap similar to an amorphous semiconductor made of tail bands and Gaussian distribution deep level bands. Consequently, and by adjusting and investigating the effect of the σRMS and the constituents of the bandgap states, we were able to obtain a good agreement between simulated and measured EQE characteristics of the solar cell

REALISATION D’UNE INTERFACE DE SIMULATION DES PERFORMANCES DES INSOLATEURS PLANS

L’utilisation des énergies renouvelables comme sources d’énergie dans lesprocessus énergétiques industrielspermet de réduire la demande énergétique en matière d’hydrocarburesetla diminution des gaz à effet de serre ainsi qued’encourager l’utilisation des ressources durables en énergies propres. Dans ce travailnous nous intéressons à la valorisation du gisement solaire dans divers sites, de climats différents, par la réalisation de cet outil de simulation du rayonnement solaire, de la température ambiante et de la température de sortie de l’insolateur. Il permettra à tout utilisateur simple ou potentiel d’avoir des informations préalables avant d’entamer un projet solaire