A molecular study of Tunisian populations of Dugesia sicula (Plathelminthes, Tricladida) through an identification of a set of genes.

Cell regeneration is a natural repair of different types of tissue after an injury or a lesion, and is associated with asexual reproduction in some animals such as planarians. Its understanding and improvement could have repercussions for tissue repair and regeneration as far as humans are concerned. In this context, we have proceeded to an essential step, which is the identification of the genes involved in planarian regeneration in the model species. Dugesia sicula Lepori (D. sicula) is distributed around the Mediterranean Sea, and this population is found in most of Tunisian dams. The collection of identified genes is already known in other species. DjFoxG, DjPC2, DjotxA, and Cathepsin-D were identified by the PCR technique and their expression was confirmed by RT-PCR and in situ hybridization. DjFoxG gene, the FoxG1 homolog, is expressed throughout the planarian body, abundantly on stem cells. Consecutively, we choose a central nervous system (CNS) marker; the prohormone convertase 2 (DjPC2) gene. DjotxA was observed in the brain and especially in the region surrounding the eyes (visual cells). The regenerative cells of the gut of D. sicula were scored by the Cathepsin-D gene expression, which belongs to the aspartyl protease family. We found significant results through RT-PCR and In Situ Hybridization (ISH) techniques, confirming the expression of DjFoxG, DjPC2, DjotxA and Cathepsin-D genes in our specimens.

Biochemical and Molecular Study of Carpobrotus edulis Bioactive Properties and Their Effects on Dugesia sicula (Turbellaria, Tricladida) Regeneration.

The traditional medicinal properties of Carpobrotus edulis are well recognized, particularly in Tunisia where it is used for wound healing. Thus, in this study, biochemical and molecular properties of its leaves' bioactive aqueous-acetone extract were investigated. The total phenolic content (TPC) of the extract was estimated to be 184 ± 5 mg/100 g of fresh matter (FM). The qualitative and quantitative polyphenolic profile was determined by ultra performance liquid chromatography with diode array detection (UPLC-DAD) and showed that chlorogenic acid was the major compound (43.7%). The extract exhibits potent antioxidant capacities with IC50 = 56.19 and 58.91 µg/ml, as accessed via the anionic DPPH and cationic ABTS radical scavenging assays, respectively. The extract has high antibacterial properties, especially against the Gram+ Staphylococcus aureus and Bacillus cereus strains. To investigate the extract effect on regeneration, the flatworm Dugesia sicula Lepori, 1948, was used as a model. The macroscopic analysis of planarian cultures in ordinary medium containing phenolic extract at non-toxic concentrations illustrated that the extract caused morphological changes. Additionally, the molecular study through the fluorescence-activated cell sorting (FACS) technique showed that C. edulis polyphenols can harm the stem cells' development. These results emphasize the ecotoxicological impact of phenolic rejections in the environment on flatworms' physiology.