The xbp-1 gene is essential for development in Drosophila.

International audienceWe report in this paper the characterization of Dxbp-1, the Drosophila homologue of the xpb-1 gene that encodes a "bZIP"-containing transcription factor that plays a key role in the unfolded protein response (UPR), an evolutionarily conserved signalling pathway activated by an overload of misfolded proteins in the endoplasmic reticulum (ER). Dxbp-1 is ubiquitously transcribed, and high levels are found in embryonic salivary glands and in the ovarian follicle cells committed to the synthesis of the respiratory appendages. Loss of function of Dxbp-1 induced a recessive larval lethality, thus, revealing an essential requirement for this gene. The Dxbp-1 transcript was submitted to an "unconventional" splicing that generated a processed Dxbp-1s transcript encoding a DXbp-1 protein isoform, as is the case for yeast, Caenorhabditis elegans and vertebrate hac1/xbp-1 transcripts after UPR activation. However, in the absence of exogenously induced ER stress, the Dxbp-1s transcript was also detectable not only throughout embryonic and larval development but also in adults with a high level of accumulation in the male sexual apparatus and, to a lesser extent, in the salivary glands of the third-instar larvae. Using a Dxbp-1:GFP transgene as an in vivo reporter for Dxbp-1 mRNA unconventional splicing, we confirmed that Dxbp-1 processing took place in the salivary glands of the third-instar larvae. The Dxbp-1 gene appears, thus, to play an essential role during the development of Drosophila, hypothetically by stimulating the folding capacities of the ER in cells committed to intense secretory activities

Etude du rôle des gènes Dfos et xbp-1 au cours des réarrangements morphogénétiques de l'épithélium folliculaire ovarien chez Drosophila melanogaster

PARIS-BIUSJ-Thèses (751052125) / SudocPARIS-BIUSJ-Physique recherche (751052113) / SudocSudocFranceF

Effect of Kappa Casein and Beta Lactoglobulin Genetic Variants on Milk Composition Traits in Tunisian Oasis Autochthonous Goats

The undertaken study was planned to investigate the influence of genetic variants of β-lactoglobulin and κ-casein loci on milk composition traits in two autochthonous Arbi and Serti goats raised in Tunisia's continental oasis region. For this purpose, blood and milk from 177 multiparous and unrelated animals were collected and used. Milk samples were analyzed for physical parameters, chemical composition, and mineral concentrations using standard methods. PCR amplification was performed using DNA samples and specific primers targeting exon 7 and 4 of β-lactoglobulin and κ-casein, respectively. To detect genetic variants, amplified products were digested with the restriction enzymes SmaI for β-lactoglobulin and HaeIII for κ-casein. The κ-casein protein had two alleles A and B, as well as two genotypes AA and AB, whereas the β-lactoglobulin showed two alleles C and T, and three genotypes CC, TT, and CT. Allele A of κ-casein occurred at a higher frequency than allele B in Arbi and Serti subpopulations and overall population. The β-lactoglobulin C allele was more common than T allele in Arbi and Serti subpopulations and throughout population. Homozygotes' frequencies were found to be higher than those of heterozygotes in all animals. Genetic polymorphism of β-lactoglobulin has been linked to milk acidity, dry matter, protein, casein, fat, lactose, Ca, P, and k content, with homozygous TT and CC genotypes clearly outperforming CT genotype. The κ-casein locus had a marked influence on the dry matter, protein, casein, and fat components, favoring homozygous AA goats in all traits except fat, which distinguished heterozygous AB goats

Evaluation of nutritional values, phenolic profile, aroma compounds and biological properties of Pittosporum tobira seeds

Abstract Background Plant essential oils and phenolic compounds are widely used for their medicinal properties. Thus, the aim of this study is to evaluate the nutritional values, the chemical composition, antioxidant activity and anti-hemolytic effects of Pittosporum tobira seeds. Methods The aroma compounds were isolated using two methods (Headspace-solid phase microextraction (HS-SPME) and hydrodistillation (HD)) and analyzed by gas chromatography coupled with mass spectrometry (GC-MS). Bioactive phenolic compounds were identified by mean of high-performance liquid chromatography (HPLC-DAD). Reducing power, hydrogen peroxide (H2O2) scavenging and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assays were used to investigate antioxidant activity. Anti-hemolytic activity was evaluated using H2O2-induced hemolysis of red blood cells (RBC). Results Oxygenated sesquiterpenes, sesquiterpene hydrocarbons and oxygenated monoterpenes were the most volatile fractions identified by HD and HS-SPME coupled to GC-MS but their quality and amount were quite different according to the extraction methodology. The main phenolic compounds identified by HPLC were caffeic acid, followed by cinnamic acid and gallic acid. P. tobira seeds essential oils showed significant antioxidant activity in DPPH (IC50 value = 1.5 mg/mL), H2O2 scavenging assay (IC50 value = 159.43 μg/mL) and reducing power test (IC50 value = 0.982 mg/mL) compared to methanolic extract. Moreover, the results revealed that the essential oil was able to protect RBC from hemolysis induced by H2O2. However, the methanolic extract had no effect on H2O2-induced hemolysis of RBC as compared to the essential oil and the standard vitamin C. Conclusions P. tobira may be used as a new natural source of antioxidant with therapeutic application in diseases caused by reactive oxygen species. Graphical Abstract Phytochemical Characterization and Biological Evaluation of Pittosporum tobira seed

The use of phosphorescence oxygen analyzer to measure the effects of rotenone and 1-methyl-4-phenylpyridinium on striatal cellular respiration in C57BL6 mice

Background: We have previously reported on the use of the phosphorescence oxygen analyzer for measuring spinal cord cellular respiration. This analytical tool is used here to investigate the effects of two inhibitors of NADH:ubiquinone oxidoreductase, rotenone and 1-methyl-4-phenylpyridinium, on cellular respiration in striatal tissue. Both neurotoxins can induce Parkinson's disease-like symptoms, and have been used to study this disease in animals. Our hypothesis is that striatal cellular respiration is a sensitive biomarker for the adverse effects of toxins, and the phosphorescence oxygen analyzer can be used as a screening tool for this purpose. Methods: Striatal fragments were collected from C57BL6 mice and immersed in Pd phosphor solution [phosphate-buffered saline, 3.0 μM ‘Pd(II)-meso-tetra (sulfophenyl) tetrabenzoporphyrin’ and 0.5% fat-free albumin, with and without 5.0 mM glucose]. The sample was transferred to a glass vial containing 2-mL Pd phosphor solution. The vial was sealed from air and placed in the instrument that measures dissolved oxygen as function of time. Immunoblots of the studied tissue were positive for the dopamine neuronal cell biomarker tyrosine hydroxylase. Results: Striatal oxygen consumption was linear with time, exhibiting zero-order kinetics of oxygen reduction by cytochrome oxidase. Cyanide sensitive respiration was ≥90%, confirming oxygen was reduced by cytochrome oxidase. The rate of respiration increased by ~2-fold in the presence of glucose. Striatal oxygen consumption in the presence of rotenone or 1-methyl-4-phenylpyridinium was exponential, demonstrating impaired respiration. Conclusion: Striatal cellular mitochondrial oxygen consumption was impaired by the studied inhibitors of complex I of the respiratory chain. This effect is expected to deplete NAD+ (oxidized nicotinamide adenine dinucleotide), a principle driver of glycolysis. In vivo studies are required to determine if these toxin-induced metabolic derangements contribute to the development of sporadic Parkinson's disease. This analytic tool can be used to screen environmental toxins for their in vitro effects on the striatum

Lycium europaeum Extract: A New Potential Antioxidant Source against Cisplatin-Induced Liver and Kidney Injuries in Mice

This study was designed to assess the protective effects of Lycium europaeum methanol extract (LEM) on liver and kidney injuries induced by cisplatin. The phytochemical composition, the antioxidant activity, and hepatorenal injury biomarkers were investigated. Results revealed that LEM exhibited a significant antioxidant activity in vitro on DPPH radical and H2O2 scavenging assays. In the animal studies, treatment with LEM significantly reduced the effects of cisplatin intoxication on serum liver biomarkers and serum renal biomarkers. Meanwhile, LEM diminishes significantly the effect of cisplatin on the level of lipid peroxidation in liver and kidney tissues. The activities of the antioxidant enzymes (reduced glutathione, glutathione peroxidase, superoxide dismutase, and catalase) were increased in groups pretreated with LEM and quercetin. Additionally, the normal histological structures of the liver and kidney were restored after treatment with LEM. This work clearly demonstrated that L. europaeum may be useful as a drug with hepato-nephroprotective potentials