Two Tunisian patients with Peters plus syndrome harbouring a novel splice site mutation in the B3GALTL gene that modulates the mRNA secondary structure

Peters plus syndrome is an autosomal recessive rare disorder comprising ocular anterior segment dysgenesis, short stature, hand abnormalities, distinctive facial features, and often other major/minor additional defects. Peters plus syndrome is related to mutations in the B3GALTL gene with only seven recently reported mutations, leading to the inactivation of the B1, 3-glucosyltransferase. In this study, we screened the B3GALTL gene in two unrelated patients with typical Peters plus syndrome. A novel homozygous c.597-2A>G mutation was identified in both patients. Bioinformatic analyses showed that this mutation modulates the pre mRNA secondary structure of the gene, and decreases the score value related to the formation of splicing loops. Moreover, the c.597-2A>G mutation is located in a CpG Island of the B3GALTL gene, suggesting a potential epigenetic role of this position including gene's methylation and regulation. These data confirm an important role of the B3GALTL gene test that provides diagnosis confirmation and improves genetic counseling for the families.     

Association of three polymorphisms of scavenger receptor class BI gene (exon8, exon1, intron5) with coronary stenosis in a coronary Tunisian population

Background

The potential role of scavenger receptor class BI (gene name SCARB1) in the regulation of lipoproteins metabolism and atherosclerosis has attracted considerable interest. We tested the relationship of SCARB1 polymorphisms with significant coronary stenosis (SCS) and lipid profile in a coronary Tunisian population.

Methods

Three SCARB1 polymorphisms (exon8 (C/T), exon1 (G/A), intron5 (C/T)) were studied in 316 Tunisian patients undergoing coronary angiography. SCS was defined as a luminal narrowing of ≥ 50% in at least one major coronary artery. Lipid profile was measured. Genotyping was performed using PCR–RFLP.

Results

Individuals with TT genotypes of exon8 were associated with higher concentrations of plasma HDL-C and ApoAI in the group without SCS. Carriers of T allele of exon8 were associated with 41% lower risk of SCS. This protective effect seemed to be particularly significant in women, nondiabetics and nonsmokers. Subjects homozygous for the variant allele of intron5 were significantly associated with an increased risk of SCS, particularly in smokers. AA genotype of exon1 was associated with an increased risk of SCS in diabetics and in patients with metabolic syndrome. The (CAT) haplotype was associated with increase in the risk of SCS compared to the wild haplotype and had a 4-fold greater risk of SCS than patients with haplotype (TGC) which seems to be the most protective against SCS.

Conclusion

Carriers of T allele of exon8 in SCARB1 seemed to increase HDL-C and ApoAI concentrations and reduce the risk of SCS. The intron5, exon1 and (CAT) haplotype seemed to have an atherogenic effect.     

Light History Influences the Response of Fluvial Biofilms to Zn Exposure

Fluvial biofilms are subject to multistress situations in natural ecosystems, such as the co‐occurrence of light intensity changes and metal toxicity. However, studies simultaneously addressing both factors are rare. This study evaluated in microcosm conditions the relationship between short‐term light intensity changes and Zn toxicity on fluvial biofilms with long‐term photoacclimation to different light conditions. Biofilms that had long‐term photoacclimation to 25 μmol photons · m^?2 · s^?1 (low light [LL] biofilms), 100 μmol photons · m^?2 · s^?1 (medium light [ML] biofilms), and 500 μmol photons · m^?2 · s^?1 (high light [HL] biofilms) were characterized by different structural (Chlorophyll‐a [Chl‐a], total biomass‐AFDW, EPS, algal groups, and diatom taxonomy) and physiological attributes (ETR‐I curves and photosynthetic pigments). HL biofilms showed higher light saturation intensity and a higher production of xanthophylls than LL biofilms. In contrast, LL biofilms had many structural differences; a higher proportion of diatoms and lower AFDW and EPS contents than ML and HL biofilms. A clear effect of light intensity changes on Zn toxicity was also demonstrated. Zn toxicity was enhanced when a sudden increase in light intensity also occurred, mainly with LL biofilms, causing higher inhibition of both the Φ′_PSII and the Φ_PSII. A decoupling of NPQ from de‐epoxidation reaction (DR) processes was also observed, indicating substantial damage to photoprotective mechanisms functioning in biofilms (i.e., xanthophyll cycle of diatoms) due to Zn toxicity. This study highlights the need to take into account environmental stress (e.g., light intensity changes) to better assess the environmental risks of chemicals (e.g., metals).     

Induction of DNA fragmentation, chromosome aberrations and micronuclei by cisplatin in rat bone-marrow cells: protective effect of recombinant human erythropoietin

Cisplatin (Cisp) is one of the most effective chemotherapeutic agents. However, at higher doses several side effects may occur. Recombinant human erythropoietin (rhEPO), a glycoprotein regulating haematopoiesis, has recently been shown to exert an important cyto-protective effects in many tissues. The purpose of this study was to explore whether rhEPO protects against Cisp-induced genotoxicity in rat bone-marrow cells. Adult male Wistar rats were divided into six groups of 18 animals each: control group, rhEPO-alone group, Cisp-alone group and three rhEPO+Cisp-groups (pre-, co- and post-treatment condition, respectively). Our results show that Cisp induced a noticeable genotoxic effect in rat bone-marrow cells. In all types of treatment, rhEPO significantly decreased the frequency of micronuclei, the percentage of chromosome aberrations and the level of DNA damage. The protective effect of rhEPO was more efficient when it was administrated 24h before exposure to Cisp.     

Changes in the antioxidative systems of Ocimum basilicum L. (cv. Fine) under different sodium salts

The effects of different sodium salts on some physiological parameters and antioxidant responses were investigated in a medicinal and aromatic plant, Ocimum basilicum L. (cultivar Fine). Plants were subjected to an equimolar concentration of Na₂SO₄ (25?mM) and NaCl (50?mM) for 15 and 30?days. Growth, oxidative stress parameters [electrolyte leakage, peroxidation, and hydrogen peroxide (H₂O₂) concentration], antioxidant enzyme activities [ascorbate peroxidase (APX, EC 1.11.1.11), glutathione reductase (GR, EC 1.6.4.2), and peroxidases (POD, EC 1.11.1.7)], as well as antioxidant molecules [ascorbate and glutathione] were determined. The two salts affected leaf growth rates to the same extent, after 15 or 30?days of treatment, indicating a similar effect of Na₂SO₄ and NaCl salinity on growth, even if different (enzymatic and non-enzymatic) antioxidant mechanisms were involved in H₂O₂ detoxification. However, under both salts, the efficiency of the antioxidant metabolism seemed to be sufficient to avoid the deleterious effects of reactive oxygen species (ROS). Indeed, both ion leakage and peroxidation did not change under either Na₂SO₄ or NaCl salinity. As a whole, these data suggest that a cooperative process between the antioxidant systems is important for the tolerance of Ocimum basilicum L., cv. Fine to Na₂SO₄ and NaCl salinity.     

Variation of volatiles in Tunisian populations of Thymbra capitata (L.) Cav. (Lamiaceae)

Volatiles from 14 wild Tunisian populations of Thymbra capitata (=Thymus capitatus Hoffmanns. et Link=Coridothymus capitatus Rchb.f.), sampled in five ecological areas (sub-humid, upper semi-arid, mean semi-arid, lower semi-arid, and upper arid areas) were analyzed by gas chromatography (GC) and gas chromatography/mass spectrometry (GC/MS) techniques. Thirty-nine constituents representing 94.2 to 99.5% of the total oil were identified. Carvacrol (38; 51.1-75.9%), p-cymene (13; 3.7-15%), γ-terpinene (12; 1.4-11.9%), and trans-β-caryophyllene (22; 2.9-4.6%) are the major compounds. A significant variation among populations and population's bioclimatic stage for the majority of compounds was shown. The chemical population structure, estimated using a principal-component analysis (PCA) and an unweighted pair group method with arithmetic mean (UPGMA) cluster analysis performed on all populations and compounds and based on Euclidean distances among populations, was high. Both methods allowed separation of the populations into distinct groups defined rather by minor than by major compounds. The spatial compound distribution is linked to ecological factors, indicating that local selective environmental factors influence chemical-composition diversity. Conservation strategies should involve all populations because of their low size and their high level of destruction. Populations exhibiting particular compounds other than the major ones should first be protected. In situ conservation of populations should be accomplished appropriately according to bioclimate.     

Combined Proteomic and Molecular Approaches for Cloning and Characterization of Copper–Zinc Superoxide dismutase (Cu, Zn-SOD2) from Garlic (Allium sativum)

Superoxide dismutases (SODs; EC 1.15.1.1) are key enzymes in the cells protection against oxidant agents. Thus, SODs play a major role in the protection of aerobic organisms against oxygen-mediated damages. Three SOD isoforms were previously identified by zymogram staining from Allium sativum bulbs. The purified Cu, Zn-SOD2 shows an antagonist effect to an anticancer drug and alleviate cytotoxicity inside tumor cells lines B16F0 (mouse melanoma cells) and PAE (porcine aortic endothelial cells). To extend the characterization of Allium SODs and their corresponding genes, a proteomic approach was applied involving two-dimensional gel electrophoresis and LC-MS/MS analyses. From peptide sequence data obtained by mass spectrometry and sequences homologies, primers were defined and a cDNA fragment of 456?bp was amplified by RT-PCR. The cDNA nucleotide sequence analysis revealed an open reading frame coding for 152 residues. The deduced amino acid sequence showed high identity (82-87%) with sequences of Cu, Zn-SODs from other plant species. Molecular analysis was achieved by a protein 3D structural model.     

Yield and seed quality of two N<Subscript>2</Subscript>-fixing common bean cultivars grown on calcareous soil

Legume seeds such as common bean (Phaseolus vulgaris L.) are of major importance for human nutrition in the Mediterranean region, owing to their high protein and iron contents. Iron deficiency is a major agricultural issue limiting crop yields, especially on calcareous soils which represent more than 30% of the world’s land surface. In the present study, we compared the effect of iron deficiency on the yield and the seed quality of two common bean cultivars, contrasting in their tolerance ability to iron deficiency. Seedlings were inoculated with an efficient strain of Rhizobium tropici CIAT 899 and were grown on either non-calcareous or calcareous soil. Seed and pod numbers, seed weight and quality were evaluated. On the calcareous soil, iron deficiency decreased the plant yield, reduced the weight and the number of seeds and impaired the seed quality as expressed by seed mineral composition, protein and soluble sugar contents. The tolerant cultivar, Flamingo, grew better and produced seeds with higher protein and mineral contents than the sensitive cultivar, Coco blanc.     

Analyse morphométrique semi quantitative de l’histologie testiculaire au cours du vieillissement

Testicular aging is usually studied using sperm and quantitative hormone analysis. Testicular samples are obviously difficult to obtain from a control aging population. Body donations from the Anatomy Department of the Saint-Peres University provided access to testicular samples from deceased men between the ages of 53 to 102 years. We present the first results of a semiquantitative histological morphometric study of testicular aging. We studied a series of 39 subjects. After removal of the sample within the first 24 hours, several investigations were conducted. Macroscopic examination (volume, weight) was followed by histological examination and computer-assisted morphometric analysis: N.I.H images based on the following parameters: (i) transverse sections of the seminiferous tubules (total surface, thickness of the basal membrane, and nuclear density of Sertoli cells, spermatogonia, spermatocytes and spermatozoids; (ii) histological sections were studied for interstitial tissue, number of clusters and the surface occupied by Leydig cells (percentage per parenchyma area), their appearance, size and nuclear density were determined; (iii) this study was completed by visual count of the various cell types in the seminiferous epithelium. The results obtained on a series of 39 subjects aged from 53 to 102 showed various alterations, such as thickening of the tunica albuginea and basal membrane and intertubule hyalinization. The most frequent histological pattern of the aging testis is a mosaic of various seminiferous tubule lesions varying from tubules with complete although reduced spermatogenesis to entirely sclerosed tubules. Individual variations are extremely marked with major alterations of spermatogenesis as early as 60 years old, with atrophied Leydig cells and, on the contrary, preserved spermatogenesis until the age of 95 years.