of marine red seaweeds (Jania rubens, Corallina mediterranea and Pterocladia capillacea), J. Taibah Univ. Sci. (2015), http://dx. AbstractSeaweeds are potential renewable resources in the marine environment. The antibacterial activity of Jania rubens, Corallina mediterranea and Pterocladia capillacea were analyzed against human pathogenic bacteria. The present study was performed to investigate the phytochemical constituents of seaweeds, such as alkaloids, flavonoids, steroids, terpenoids and phlobatannins. In this study, we estimated phenols, flavonoids, tannins, pigments and mineral contents and determined the hydrogen peroxide scavenging activity, reducing power and total antioxidant activity of various extracts of selected seaweeds. Phytochemicals were extracted from the three seaweeds using various solvents, such as methanol, ethanol, acetone and chloroform. Among the various extracts, the methanolic extract was found to have the highest reducing power and total antioxidant capacity. We evaluated the seaweeds against Vibrio fluvialis, and Pterocladia capillacea was the most effective at controlling its growth. The highest zone of inhibition was recorded in the methanol extract. The chemical constituents of the seaweeds were characterized by GC-MS, which showed that they contain organic compounds, such as 1,2-benzenedicarboxylic acid.

No abstract

No abstract

No abstract

The roles of pendimethalin and its nano-form to induce oxidative stress, osmolytes, biochemical alterations and cytotoxic effect in algal cells of Chlorella vulgaris after exposure to sub-lethal concentrations were carried out. The data indicated that, 96-h EC 50 values were 20 and 19 ppb for pendimethalin and its nano-form, respectively. Three concentration levels (0.1EC 50 , 0.025EC 50 and EC 50 ) of the examined herbicide decreased the algal pigments (Chlorophyll a and b), but increased carotenoid contents compared with the control group. Biomolecules such as protein, carbohydrates, proline and sucrose of the algal cells significantly increased for the all treatments compared with the control groups. Similarly, malondialdehyde (MDA), some enzymes such as catalase (CAT), superoxide dismutase (SOD) and ascorbate peroxidase (APX) showed significant increases for the all treatments. On the other hand, ultrastructural investigation of the herbicide-treated algal cells showed significant changes in their organelles in comparing with the untreated cells through transmission electron microscope (TEM) images. From all findings, it was obtained that the nano-pendimethalin was more potential toxic than the traditional form to induce adverse effects on the freshwater alga. Thus, biosafety procedures must be followed on non-target species before decision for nano-herbicide practices.