Genetic Background of ß-Thalassemia in Northeast Algeria with Assessment of the Thalassemia Severity Score and Description of a new ß0-Thalassemia Frameshift Mutation (HBB: c.374dup; p.Pro126Thrfs*15).

ß-Thalassemia (ß-thal) is a genetic disorder representing a major health problem in Algeria. Our first objective was to determine the allelic frequencies and molecular spectrum of ß-thal mutations in patients with major hemoglobinopathies [ß-thal major (ß-TM) and sickle cell disease] in three provinces of northeast Algeria. Our second objective was to assess if the clinical management of ß-TM patients depended on their region of origin. Our last objective was to assess a population originating from Maghreb, the reliability of the thalassemia severity score (TSS) for patients with homozygous ß-thal. Sanger HBB gene sequencing was performed on 59 patients with sickle cell disease and 60 with ß-TM. For the latter patients, the genetic modifiers of the TSS were genotyped: α-thalassemia (α-thal) deletions and four Hb F-inducing polymorphisms (XmnI, rs1427407 and rs10189857 for BCL11A and rs9399137 for HMIP). Eleven different ß-thal mutations were found but two of them (HBB: c.118C>T and HBB: c.93-21G>A) accounted for about 70.0% of the ß-thal alleles. A relatively high proportion of Hb S (HBB: c.20A>T)/ß-thal genotypes (27.0%) was found in our sickle cell disease cohort where a new frameshift ß0-thal mutation (HBB: c.374dup; p.Pro126Thrfs*15) was identified. No difference was found in the three provinces. Of the 60 ß-TM patients, those with a high or very high TSS were significantly younger at the age of first transfusion, thus assessing the reliability of this scoring system in a Maghrebin cohort. Trends for a lower age of splenectomy and high ferritin levels were also detected for the higher TSS categories.

Ames and random amplified polymorphic DNA tests for the validation of the mutagenic and/or genotoxic potential of the drinking water disinfection by-products chloroform and bromoform.

Chloroform and Bromoform are two abundant trihalomethanes found in Algerian drinking water. The investigation of the mutagenic hazard of these disinfection by-products was studied by Ames test as prokaryotic bioassay to show their mutagenic effects. For this, Salmonella typhimurium TA98 and TA100 strains were employed. Both chloroform and bromoform showed a direct mutagenic effect since the number of revertant colonies gradually increase in dose-dependent manner with all concentrations tested with the two bacterial strains and these were both in the absence and presence of S9 metabolic activation. The genotoxic hazard was also studied by random amplified polymorphic DNA test on the root cells of Allium cepa as eukaryotic bioassay. DNA extracted from the roots of the onion were incubated at different concentrations of chloroform and bromoform and then amplified by polymerase chain reaction. This was based on demonstrating a major effect of disappearance of bands compared to roots incubated in the negative control (distilled water). The results showed that these two compounds affected genomic DNA by breaks although by mutations.

Mutagenicity and genotoxicity assessments of some industrially processed meat products in Algeria.

Processed meat products are presumptive sources of mutagens and genotoxins for consumers. Several epidemiological studies have reported that these products' high intakes have a positive link with cancer incidence. In Algeria, industrially processed meat products are widely consumed. However, there are no earlier studies involving their genotoxic activity. For this end, the current study aimed at evaluating the mutagenicity and the genotoxicity of some representative industrially processed meat products sold in popular supermarkets. All samples were extracted by established method, using both polar and non-polar solvents. The meat extracts mutagenicity was assessed by Ames test, using four strains of Salmonella typhimurium in the presence and absence of metabolic activation, and subsequently by treat and wash assay for extracts showing biologically significant results. The genotoxicity was determined in TK6 human lymphoblastoid cells using the in vitro micronucleus assay in micromethod. The results showed that all extracts analyzed induce no mutagenic activity. However, one of these extracts induced a biologically significant increase in the number of micronucleated cells. Our findings indicate the importance of the genetic damage detection for taking measures to suppress or reduce the exposure to harmful contaminants and encourage further research investigating genotoxic effects of industrially processed meat worldwide.

Mitotic timing is differentially controlled by A- and B-type cyclins and by CDC6 associated with a bona fide CDK inhibitor Xic1 in Xenopus laevis cell-free extract.

The timing of the M-phase is precisely controlled by a CDC6-dependent mechanism inhibiting the mitotic histone H1 kinase. Here, we describe the differential regulation of the dynamics of this mitotic kinase activity by exogenous cyclin A or cyclin B in the Xenopus laevis cycling extracts. We show that the experimental increase in cyclin A modifies only the level of histone H1 kinase activity, while the cyclin B increase modifies two parameters: histone H1 kinase activity and the timing of its full activation, which is accelerated. On the other hand, the cyclin A depletion significantly delays full activation of histone H1 kinase. However, when CDC6 is added to such an extract, it inhibits cyclin B-associated histone H1 kinase, but does not modify the mitotic timing in the absence of cyclin A. Further, we show via p9 co-precipitation with Cyclin-Dependent Kinases (CDKs), that both CDC6 and the bona fide CDK1 inhibitor Xic1 associate with the mitotic CDKs. Finally, we show that the Xic1 temporarily separates from the mitotic CDKs complexes during the peak of histone H1 kinase activity. These data show the differential coordination of the M-phase progression by cyclin A- and cyclin B-dependent CDKs, confirm the critical role of the CDC6-dependent histone H1 kinase inhibition in this process, and show that CDC6 acts differentially through the cyclin B- and cyclin A-associated CDKs. This CDC6- and cyclins-dependent mechanism likely depends on the precisely regulated association of Xic1 with the mitotic CDKs complexes. We postulate that: i. the dissociation of Xic1 from the CDKs complexes allows the maximal activation of CDK1 during the M-phase, ii. the switch between cyclin A- and cyclin B-CDK inhibition upon M-phase initiation may be responsible for the diauxic growth of mitotic histone H1 kinase activity.

The effect of silver nanoparticles on the mutagenic and the genotoxic properties of the urban wastewater liquid sludges.

Nanoparticles are very effective compounds to transform and detoxicate common environmental contaminants. For this reason, crude urban liquid wastewater sludges were treated by silver nanoparticles (Ag-NPs, 100 nm) for 24 h. Both Ag-NPs' treated and untreated sludges were examined for the evaluation if there are possible mutagenic/anti-mutagenic, cytotoxic, and genotoxic/anti-genotoxic effects by Ames and Allium cepa tests. The results were then subjected to statistical analyses by using SPSS software and p < 0.05 was accepted as a significant value. The data obtained from the Ames test showed that while untreated crude liquid sludge had a significant mutagenic effect, Ag-NP-treated one decreased its mutagenicity. Similar effects were also observed in the chromosome aberration-Allium cepa tests. Significant chromosome aberrations observed were C-metaphase, sticky metaphase, sticky anaphase, anaphase bridge, vagrant chromosome, and multipolar anaphases. Both tests demonstrated that silver nanoparticle treatment decreased the major mutagenicity and genotoxicity detected in the liquid wastewater sludges.