Soad Mohamed Mohy El.Din

Nadia H. Noaman, Khaled Y. Abdel-Halim, Soad M. Mohy El-Din and Manal M. El-Abasy 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.

Spirulina is aquatic and photosynthetic organisms and it is a good source of c-phycocyanin pigments. They are widely utilized as food supplement because it contains significant amount of proteins. This investigation is an effort to study some of medicinal applications of Spirulina platensis such as antioxidant capacity, antimicrobial, cholesterol- reduction and anticancer. Antimicrobial activity of methanol, acetone, chloroform and petroleum ether extracts of dried Spirulina platensis was assayed against two fungi (Aspergillus flavus and Aspergillus niger) and four bacterial species (Staphylococcus aureus, Bacillus subtilus, Escherchia coli and Salmonella typhi). The Spirulina platensis extracts exhibited significant activity against all tested bacteria and fungi. The highest inhibition zone (1.18±0.04 cm) was observed in acetone extract against Salmonella typhi. While, petroleum ether extract of Spirulina platensis was recorded the minimum activities of all tested antimicrobial and the lowest inhibition zone against Staphylococcus aureus (0.50±0.01 cm). The antioxidant potential of solvent extracts solvent extracts. Acetone extract of Spirulina platensis showed highest percentage of DPPH scavenging activity (65.8%) and highest values of phenolic contents (0.562 mg/g DW). Spirulina platensis displays anticancer activity duo to the productions of phycocyanin, allophycocyanin and other valuable products. The Spirulina platensis extracts of various solvents evaluate its potential antitumor effects in vitro by using the Fetal Calf Serum. The cell proliferation assay showed that petroleum ether extract at a concentration of 125 µg ml-1 for 24 hours, significantly inhibited the growth of the Fetal Calf tumor cells (13% viability).

This study examines the relationship between the algal biomass as well as lipid and triglyceride contents in Isochrysis galbana and variation in nutrient culture conditions such as phosphorus concentration and iron concentration. From the selected experiments, a clear algal growth drop expressed by number of cells, optical density and dried weight, as well strongly participated in the lipid and triglyceride cumulation, which show a positive significant effect on lipid productivity and triglyceride productivity. In the first experiment of this study, the phosphorus concentration in the medium was reduced to 75%, 50%, and 25% and complete absence (0%) of the original concentration in Walne’s medium, whereas the iron concentration was kept constant in the medium. The next experiment, the optimum phosphorus concentration (25%) granting high lipid product was tested with different concentrations of iron from 100 to 0% with five concentrations. Though, the algal growth nonsignificant affected, abundant increases in lipids and triglyceride contents (49.5% and 14.7% of dry weight respectively) was noticed at the concentration of phosphorus of culture medium was decreased to (25%). However, hyperaccumulations of lipid and triglyceride (60.3% and 18.4% on the basis of dry weight, respectively) were acquired by the incorporation of 25% phosphorus and 25% iron. The simple regression analysis suggested the combination effect of phosphorus limitation and iron deprivation on lipid and triglyceride cumulation, and it was not as substantial as to phosphorus starvation tension.

TODAY the heavy metal pollution is one of the most important environmental problem, which causes in soil and aquatic environment. Biosorption is an innovative technology that employs biological materials to accumulate heavy metals from waste water through metabolic process or physicochemical pathways of uptake. We studied the metabolic responses of Spirulina platensis to the toxicity of two heavy metals,Cu2+ and Pb2+. The data show that the lower doses of metals had stimulatory effect on biomass of Spirulina platensis, whereas the higher doses were found to be inhibitory depending on the type of the metal. The inhibitory effect of copper upon growth parameters of Spirulina platensis was more pronounced than lead. The total protein content, chlorophyll content, total carbohydrate and the total free amino acids of the tested alga gradually decreased in a manner dependent on the metal concentration in the medium. Biosorption of algal biomass was found to be heavy metal concentrations and pH dependent, where Spirulina platensis accumulated the amount of Pb2+ more than Cu2+. Concerning the effect of different concentrations of Cu2+ and Pb2+ on photosynthetic O2 evolution, the results showed reduction in the amount of O2 evolved in response to increasing metals concentrations. On the other hand, the effect of the heavy metals on respiration showed that higher metals concentrations were inhibitory to O2 uptake by Spirulina platensis.