ABSTRACT
Abstract In Tunisia, Monastir bay, extending for 38 km along the eastern coast of Tunisia, harbors different species of bivalves such as the clam Ruditapes decussatus, a species of major socio-economic interest. Despite its importance, no studies have been carried out about the morphology of this mollusc in Monastir bay. Thus, the current study aimed to analyze the shell morphological variations in the European clamRuditapes decussatus from Monastir Bay coast. The comparison of the shell shape of individuals from different populations was performed based on samples taken at four different sites (Khniss, Ksiba, Bkalta and Sokrine). Variance analysis of the morphometric indices (elongation, compactness, convexity and density) for the four populations indicated significant differences among sites with (p=0<0.05). Principal component analysis (PCA) revealed two intra-population groups for Sokrine site, supporting an intra-population variation in the shell morphology. Allometric relationships established between linear variables (shell length, height and width) and ponderal variables (total weight, shell weight) as well as the relative growth between variables (isometry vs. allometry) were analyzed. All morphometric relationships were highly significant (P<0.001) with high correlation coefficients (R2: 0.714-0.982), showing positive allometric growth for Bkalta and negative allometric growth for Sokrine. The data obtained will be useful in research studies and have practical application in diverse research fields such as biology, ecology, fisheries assessment and management.
ABSTRACT
The aim of this work was to evaluate the cytotoxicity of Arthrospira platensis Extracellular Polymeric Substances (EPS) for colon cancer and kidney cell lines. Results showed that EPS were free from cytotoxic effects. A variety of solvents were assessed for their ability to extract the bioactive ingredients from EPS. Methanol gave the highest yield (75.75 percent) than other solvents. The extracts were tested for activities against a collection of Gram+/- bacteria. The methanol extract exhibited a more potent activity than the other organic extracts, whereas the aqueous extract was active against Staphylococcus epidermis (Gram+) and Salmonella typhimurium (Gram-). Finally, The extracts were also tested for the antioxidant activity, using the Trolox Equivalent Antioxidant Activity assay. The methanol extract displayed a moderate antioxidant activity (TEAC = 0.027 mg/ml). The HPLC analysis of this extract revealed two distinct peaks: 8.1 kDa (8.31 min) and 4.1 kDa (8.54 min).