An antimicrobial agent is produced by the cyanobacterium Synechococcus leopoliensis which was found to be active against the Gram-positive bacterium Staphylococcus aureus. The effects of temperature, pH, incubation period, some media and different nitrogen and carbon sources on both growth and antimicrobial activity were investigated. Temperature 35 degrees C and pH 8 were the best for growth and antimicrobial agent production and 14 and 15 days of incubation were found to be the best for maximum growth and antimicrobial activity, respectively, in the medium BG-11. No antimicrobial activity could be detected by the use of G medium, moderate activity was recorded with Chu 10 medium, while high activity was reported in BG-11 medium. Leucine was the best nitrogen source for antimicrobial activity, while maximum antimicrobial activity was introduced by using the carbon sources, citrate and acetate. Very high antimicrobial activity could be detected by using the carbon source galactose in combination with the nitrogen source alanine or by using arabinose with methionine.

HYTOREMEDIATION of waters by aquatic organisms such ……… as algae has been recently explored for the removal of organic pollutants possessing endocrine disrupting capacity. Two marines macro-algae Pterocladia capillacea and Ulva lactuca were tested for removal of chloramphenicol, clofibric acid, acetyl salicylic acid, nonylphenol and bisphenol in aqueous solutions at concentrations 5-60 mg/L under controlled laboratory conditions. The obtained results showed that chlorophyll "a" content of both algal biomasses reduced with increasing pharmaceuticals concentrations. Chlorophyll "a "content was diminished nearly to the half at concentration 45mg/L for both algal species. However, the nonylphenol and bisphenol were showed a strong inhibition of chlorophyll "a" biosynthesis at higher concentrations (50-60 mg/L). Both the Pterocladia capillacea and Ulva lactuca recorded the highest removal percentage of pharmaceuticals occurred at 12 hours of contact. Pterocladia capillacea had high capacity for bioremoval of pharmaceuticals and endocrine disruptor compounds than Ulva lactuca. The results also revealed that Pterocladia capillacea was recorded the maximum biosorption of pharmaceuticals and endocrine disruptor compounds in order nonylphenol > acetyl salicylic acid > clofibric acid > bisphenol > chloramphenicol, while the maximum biosorption exhibited by Ulva lactuca was recorded in order acetyl salicylic acid > clofibric acid > bisphenol > nonylphenol > chloramphenicol at contact time 12 hours. Both the tested algae suffered from oxidative stress as a result of pharmaceuticals and endocrine disruptor compounds exposure. Our results showed elevation in the antioxidant enzymes superoxide dismutase (SOD), ascorbate peroxidase (APO), catalase (CAT) levels in the tested algae after exposure to different pharmaceuticals when compared with their activities in the control.