Conditional inactivation of TGF-β type II receptor in smooth muscle cells and epicardium causes lethal aortic and cardiac defects

To understand the role of TGF-β signaling in cardiovascular development, we generated mice with conditional deletion of the TGF-β type II receptor (TβRII) gene (Tgfbr2) in cells expressing the smooth muscle cell-specific protein SM22α. The SM22α promoter was active in tissues involved in cardiovascular development: vascular smooth muscle cells (VSMCs), epicardium and myocardium. All SM22-Cre^+/−/Tgfbr2 ^flox/flox embryos died during the last third of gestation. About half the mutant embryos exhibited heart defects (ventricular myocardium hypoplasia and septal defects). All mutant embryos displayed profound vascular abnormalities in the descending thoracic aorta (irregular outline and thickness, occasional aneurysms and elastic fiber disarray). Restriction of these defects to the descending thoracic aorta occurred despite similar levels of Tgfbr2 invalidation in the other portions of the aorta, the ductus arteriosus and the pulmonary trunk. Immunocytochemistry identified impairment of VSMC differentiation in the coronary vessels and the descending thoracic aorta as crucial for the defects. Ventricular myocardial hypoplasia, when present, was associated to impaired α-SMA differentiation of the epicardium-derived coronary VSMCs. Tgfbr2 deletion in the VSMCs of the descending thoracic aorta diminished the number of α-SMA-positive VSMC progenitors in the media at E11.5 and drastically decreased tropoelastin (from E11.5) and fibulin-5 (from E.12.5) synthesis and/or deposition. Defective elastogenesis observed in all mutant embryos and the resulting dilatation and probable rupture of the descending thoracic aorta might explain the late embryonic lethality. To conclude, during mouse development, TGF-β plays an irreplaceable role on the differentiation of the VSMCs in the coronary vessels and the descending thoracic aorta.     

Spatio-temporal dynamics of the nematode Anguillicola crassus in Northeast Tunisian lagoons

Anguillicola crassus, parasite nematode of the European eel Anguilla anguilla, was recorded for the first time in Tunisia (1999) in the Ichkeul lagoon. Its distribution has since spread toward Bizerte and Ghar El Melh lagoons. The monthly epidemiological survey reveals that A. crassus exists throughout the year in the Ichkeul lagoon. In this lagoon, its prevalence is low in winter (12% in December), with a marked increases in the spring reaching a maximum in March (35%), before it starts to decrease in summer with a minimum in July (4.35%), which in turn is followed by a pronounced new rise in autumn (30% in November). However, mean intensity values do not show such a marked variation. The majority of the values are between 1 and 1.5 parasites per host. In the Bizerte and Ghar El Melh lagoons, the presence of this nematode is limited only to one to three months. Investigations in the Tunis lagoon did not reveal until now the presence of A. crassus. It has been observed that the length of the eel influences the prevalence values: A. crassus becomes less common if the length of the eel increases. Comparatively with the global epidemiological values of A. crassus signalled subsequently (1999) in the Ichkeul lagoon, we note that the present values record a clean increase.     

Synthesis and Characterization of New Lutidinium Ionic Liquid-Supported Vanadylsalicylaldoxime Complex for Catalytic Application in Epoxidation Reaction

A new chelating task-specific ionic liquid (TSIL), lutidinium-based salicylaldoxime ( LSOH ), and its square pyramidal vanadyl(II) complex (VO(LSO)₂) have been successfully synthesized and structurally characterized using elemental (CHN), spectral, and thermal analyses. The catalytic activity of the lutidinium-salicylaldoxime complex (VO(LSO)₂) in the alkene epoxidation reactions was studied under various reaction conditions, such as solvent effect, alkene/oxidant molar ratio, pH, reaction temperature, reaction time, and the catalyst dose. The results demonstrated that the CHCl₃ solvent, 1 : 3 of the cyclohexene/H₂O₂ ratio, pH 8, temperature of 340 K, and catalyst dose of 0.012 mmol are assigned as the optimum conditions for achieving maximum catalytic activity for VO(LSO)₂. Moreover, the VO(LSO)₂ complex has the potential for application in the effective and selective epoxidation of alkenes. Notably, under optimal VO(LSO)₂ conditions, cyclic alkenes convert more efficiently to their corresponding epoxides than linear alkenes.     

DNA barcoding of marine fishes from Saudi Arabian waters of the Gulf

We used the cytochrome oxidase subunit I (coI) gene DNA to barcode 117 endemic Gulf and cosmopolitan Indo–West Pacific fish species belonging to 54 families and 13 orders. Novel DNA barcodes were provided for 18 fish species (Trachinocephalus sp., Nematalosa sp., Herklotsichthys lossei, Upeneus doriae, Trachurus indicus, Apogonichthyoides taeniatus, Verulux cypselurus, Favonigobius sp., Suezichthus gracilis, Sillago sp., Brachirus orientalis, Pegusa sp., Lepidotrigla bispinosa, Lepidotrigla sp., Grammoplites suppositus, Hippichthys sp., Paramonacanthus sp. and Triacanthus sp.). The species delimitation analysis, conducted with Poisson tree processes– Bayesian PTP (PTP–bPTP) and nucleotide-divergence-threshold (NDT) models), found 137 and 119 entities respectively. Overall, NDT method, neighbour-joining species tree and the prior taxonomic assessment provided similar results. Among the 54 families considered, only 10 (Ariommatidae, Ephippidae, Leiognathidae, Nemipteridae, Plotosidae, Pomacanthidae, Pomacentridae, Priacanthidae and Rachycentridae) showed the occurrence of molecular diagnostic pure characters. The DNA barcoding database developed during this study will help ichthyologists to identify and resolve the taxonomic ambiguities they may encounter with the fishes occurring in The Gulf and throughout the region.     

Increased insulin sensitivity and reduced adiposity in phosphatidylinositol 5-phosphate 4-kinase beta-/- mice

Phosphorylated derivatives of the lipid phosphatidylinositol are known to play critical roles in insulin response. Phosphatidylinositol 5-phosphate 4-kinases convert phosphatidylinositol 5-phosphate to phosphatidylinositol 4,5-bis-phosphate. To understand the physiological role of these kinases, we generated mice that do not express phosphatidylinositol 5-phosphate 4-kinase beta. These mice are hypersensitive to insulin and have reduced body weights compared to wild-type littermates. While adult male mice lacking phosphatidylinositol 5-phosphate 4-kinase beta have significantly less body fat than wild-type littermates, female mice lacking phosphatidylinositol 5-phosphate 4-kinase beta have increased insulin sensitivity in the presence of normal adiposity. Furthermore, in vivo insulin-induced activation of the protein kinase Akt is enhanced in skeletal muscle and liver from mice lacking phosphatidylinositol 5-phosphate 4-kinase beta. These results indicate that phosphatidylinositol 5-phosphate 4-kinase beta plays a role in determining insulin sensitivity and adiposity in vivo and suggest that inhibitors of this enzyme may be useful in the treatment of type 2 diabetes.     

Integrated analysis for identifying Portulaca oleracea and its sub-species based on chloroplastic and nuclear DNA barcoding

The taxonomy of Portulaca oleracea has been considered as being complex since the aggregate is composed of many subspecies or a group of micro-species based on seed-coat characters, seed size, and chromosome number. In order to enlarge the background of the extent of genetic variability between and within Tunisian P. oleracea accessions, a combined morphological and molecular approach was adapted, in the present survey. The morphological analyses of the spontaneous Tunis population display high intra population variability characterized by two distinct morphotypes corresponding to the botanical forms (wild and cultivated plant). Furthermore, the molecular approach based on sequences data related to chloroplastic and ribosomal DNA, was used to understand this variability. The obtained results highlighted the greater molecular variability of this plant and allowed to segregate between morphotypes and genotypes of Portulaca. Mostly, this work shows the important contribution of DNA barcoding approach in resolving low-level-taxonomy problems to distinguish between natural populations and varieties.     

Effect of dietary fiber of “Rihane” barley grains and azoxymethane on serum and liver lipid variables in Wistar rats

The aim of the present study is to evaluate the effects of diet enriched with dietary fiber of barley variety “Rihane” and azoxymethane on serum and liver lipid variables in male rats. Forty male rats were divided into four groups and fed on control diet or experimental diet that contained control enriched with dietary fiber of barley variety “Rihane”. Animals were injected with saline (controls) or azoxymethane (20 mg/kg body weight s.c.) at 7 and 8 weeks of age. The experimental diet significantly decreased cholesterol level compared with the control diet. Rats fed with BR diet significantly increased the serum high-density lipoprotein (HDL) cholesterol and significantly decreased low-density lipoprotein (LDL) cholesterol concentrations. The experimental diet decreased the atherogenic index (p < 0.05) compared with the control diet. Whereas the azoxymethane induced a significant increase of liver lipid, serum LDL and triglyceride concentrations, but it caused a significant reduction of HDL. Consequently, the ratio of HDL/TC decreased significantly compared with the control (p < 0.05). Accordingly, these results indicated that the diet enriched with dietary fiber of barley variety “Rihane” could be effective in decreasing the atherogenic risk factors in rats whereas the use of the azoxymethane as colon-specific carcinogen substance altered the lipid metabolism.     

Effects of l-glutamine supplementation alone or with antioxidants on hydrogen peroxide-induced injury in human intestinal epithelial cells

Background and aimsIn situations of oxidative stress, l-glutamine (Gln) exhibits protective effects which may be potentiated by its combination with antioxidants. The aim of this study was to compare the effects of a Gln-antioxidants formula vs Gln alone in intestinal epithelial cell lines Caco-2 and HCT-8 submitted to hydrogen peroxide-induced oxidative injury.MethodsCells were cultured during 24 h with 0, 1, 2, 4, 8 or 16 mM Gln or isomolar Gln combined to cysteine, vitamine C, vitamine E, β-carotene, Zn and Se (Gln-AOX). After 24 h, membrane integrity was assessed by means of LDH leakage, the level of oxidative stress by analysis of 8-isoprostane concentration and cell viability by colorimetric-MTT assay.ResultsLDH activity decreased (P < 0,05) with a dose-dependent manner in both cell types with Gln-AOX whereas Gln decreased LDH release only in the Caco-2 line at 1 mM. For both cell lines, release of 8-isoprostane was not blunted by any treatment and increased paradoxically with 16 mM Gln (P < 0.05). Cell viability was higher (P < 0.05) using Gln-AOX vs Gln at 4, 8 and 16 mM in both cell lines.ConclusionsThese results suggest that Gln-AOX is more efficient than Gln alone to preserve cell membrane integrity and viability in intestinal cell lines submitted to oxidative injury.     

Genetic Diversity of Food-Isolated Salmonella Strains through Pulsed Field Gel Electrophoresis (PFGE) and Enterobacterial Repetitive Intergenic Consensus (ERIC-PCR)

All over the world, the incidence of Salmonella spp contamination on different food sources like broilers, clams and cow milk has increased rapidly in recent years. The multifaceted properties of Salomnella serovars allow the microorganism to grow and multiply in various food matrices, even under adverse conditions. Therefore, methods are needed to detect and trace this pathogen along the entire food supply network. In the present work, PFGE and ERIC-PCR were used to subtype 45 Salmonella isolates belonging to different serovars and derived from different food origins. Among these isolates, S. Enteritidis and S. Kentucky were found to be the most predominant serovars. The Discrimination Index obtained by ERIC-PCR (0.85) was slightly below the acceptable confidence value. The best discriminatory ability was observed when PFGE typing method was used alone (DI = 0.94) or combined with ERIC-PCR (DI = 0.93). A wide variety of profiles was observed between the different serovars using PFGE or/and ERIC-PCR. This diversity is particularly important when the sample origins are varied and even within the same sampling origin.