DNA methylation in adults and during development of the self‐fertilizing mangrove rivulus,Kryptolebias marmoratus

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.     

Composition du liquide seminal de Sparus aurata au cours d'une saison de spermiation

Résumé Du sperme de daurade Sparus aurata est prélevéà diffkrentes dates de la saison de spermiation. La composition biochimique du plasma séminal est analyské.
La concentration des éléments dosés est généralement plus importante que chez les espèces d'eau douce. La teneur en protéines reste constante au cours du temps. La quantité de glucose accuse une diminution à partir de la mi-décembre. Les triglycérides et le cholesterol atteignent des valeurs relativement elevees aux dates limites de la période d'échantillonnage, tandis que le taux de calcium est minimal à la fin de la saison de spermiation.     

An avifaunal survey of mesic manmade ecosystems “Oases” in algerian hot-hyperarid lands

Man made ecosystems of dry lands are key habitats due to their ecological characteristics to survey biodiversity. This study investigated bird diversity in three oases of the Northern Algerian Sahara (i.e., Biskra in 2006, Oued Souf in 2008 and Ouargla in 2009), by using the spot-mapping method. Bird density “D” (pairs/10 ha), species richness “S” (number species), diversity (Shannon index) “H′” (in bits), and evenness “E” varied from one oasis to another (Biskra: D = 98.5, S = 47, H′ = 4.49, E = 0.81; Oued Souf: D = 96, S = 33, H′ = 3.9, E = 0.77; Ouargla: D = 91.5, S = 44, H′ = 4.39, E = 0.80). Differences in bird diversity between the monitored palm groves are due to the ecological characteristics of each environment. Documented literature outlined close taxonomic similarities between bird assemblages of the study area with many Northern Saharan oases. The Hybrid Sparrow Passer domesticus x Passer. hispaniolensis and some Columbidae species including Columba livia, Streptopelia turtur, Streptopelia senegalensis, and Streptopelia decaocto were the abundant species throughout surveyed oases in which they represented more than half (55.6%) of the sum of species densities (D = 286 pairs/10 ha). These synthropic species have known a huge expansion of their distribution range throughout Algerian oases. The correspondence analysis allowed the aggregation of both families and species into oasis they belong to. One-way ANOVA was tested to analyse variations of both family and species densities between studied oases. The ANOVA revealed there was no significant variation either in family densities (p = 0.937) or in bird densities (p = 0.622) between the surveyed oases because of the small size of bird populations.     

Importance de la Mérione de Shaw Meriones shawii au sein des composantes trophiques de la Chouette effraie Tyto alba en milieux steppiques de l’Algérie

The study of the diet of the Barn Owl in two steppic regions (M'Sila and Djelfa) located in the Algerian highlands is based on the analysis of the pellets of rejections collected in six stations. The analysis of 706 pellets resulting from the various stations made it possible to count 1380 individuals, represented by seven classes, 12 orders, 32 families, and 76 species of preys. The mammals are consumed with variable abundance rates between 59.1 % and 90.0 % whose predominance is assigned to the rodents (relative abundance: AR > 58 %). The latter constitute the most advantageous preys in biomass (61.4 ≤ B % ≤ 99.2). The most consumed prey is Meriones shawii, with variable rates between 31.9 % and 76.6 %. Generally, Tyto alba presents a diversified diet in the majority of the stations (0.69 ≤ E ≤ 0.76), except the station of Ain El-Hadjel (E = 0.35), with a low diversity and dominance of M. shawii (AR = 76.6 %).     

Comparative analysis of prostatic acid phosphatase and prostate-specific antigen mRNA levels in hyperplastic prostate stimulated with steroid hormones and growth factors

Prostatic acid phosphatase (PAP) and prostate-specific antigen (PSA) are the markers of human prostatic gland. However, it is still not completely understood if and how, steroid hormones and growth factors affect their expression and metabolism in the respect to the major pathologies of the gland. Appropriate studies were carried out on histopathologically diagnosed benign prostatic hyperplasia--BPH (n = 42) using tissue slices and cells derived from them. They were incubated with steroid hormones: 5-alpha-dihydrotestosterone (DHT), estradiol (E) and growth factors: epidermal growth factor (EGF), basic fibroblastic growth factor (bFGF) under culture conditions for up to 24 hours. P-labelled specific oligonucleotide probes were used to analyze total RNA isolated from each sample for the presence of PAP and PSA mRNAs. DHT, E, bFGF, EGF or both DHT + bFGF and DHT + EGF increased PAP and PSA mRNA levels in a time- and dose-dependent manner. The highest and statistically significant increase (P < 0.001) for PAP mRNA was observed when DHT + bFGF were present in the medium while for PSA mRNA if DHT + EGF were added to the medium. Slow but constant decrease of PAP and PSA mRNA levels was observed in the absence of each of these factors in the incubation medium. The results suggest that early expression of PSA and PAP genes and/or their mRNA stability strongly depend on DHT while differ in their response to EGF and bFGF.     

A novel approach for removing an industrial dye 4GL by an Algerian Bentonite

Adsorption processes of 4GL on two different bentonite-based sorbents were compared: i) Sodium-bentonite in the presence of a cationic surfactant CTAMB; ii) organobentonite alone. This latter was prepared by exchanging the inorganic cation of bentonite with a quaternary ammonium cation at 100% of the clay's CEC. Batch adsorption studies were conducted to evaluate the effect of various parameters such as the quaternary ammonium cation (CTAMB) loading, contact time and initial 4GL concentration.From the kinetic study, it is interesting to note that Organobentonite exhibits faster kinetics compared to Na-bentonite/CTAMB system. The comparison between isotherm plots makes clear that the presence of CTAMB in solution changes the 4GL isotherm. Compared to organobentonite, the adsorption capacity is higher when CTAMB was present in solution. In this case, the results of 4GL adsorption by bentonite obey to Langmuir model. While for organobentonite, all models seem to be applicable. The difference between the two methods is confirmed by XRD analysis.The performance shown by Organobentonite and Na-bentonite/CTAMB system was suitable compared to other adsorbents, reflecting a promising future utilization in wastewater treatment.     

The pseudokinase NIPI-4 is a novel regulator of antimicrobial peptide gene expression

Hosts have developed diverse mechanisms to counter the pathogens they face in their natural environment. Throughout the plant and animal kingdoms, the up-regulation of antimicrobial peptides is a common response to infection. In C. elegans, infection with the natural pathogen Drechmeria coniospora leads to rapid induction of antimicrobial peptide gene expression in the epidermis. Through a large genetic screen we have isolated many new mutants that are incapable of upregulating the antimicrobial peptide nlp-29 in response to infection (i.e. with a Nipi or ‘no induction of peptide after infection’ phenotype). More than half of the newly isolated Nipi mutants do not correspond to genes previously associated with the regulation of antimicrobial peptides. One of these, nipi-4, encodes a member of a nematode-specific kinase family. NIPI-4 is predicted to be catalytically inactive, thus to be a pseudokinase. It acts in the epidermis downstream of the PKC∂ TPA-1, as a positive regulator of nlp antimicrobial peptide gene expression after infection. It also controls the constitutive expression of antimicrobial peptide genes of the cnc family that are targets of TGFß regulation. Our results open the way for a more detailed understanding of how host defense pathways can be molded by environmental pathogens.