الفهرس 
1. INTRODUCTIONOnly 14 pages are availabe for public view
 |  | from | 258 |  |  |
| | | from | 258 | | |
Abstract
1- Forty three different isolates of non-pathogenic bacteria isolated from some cultivated soils, air, and water of Egypt. The isolates were isolated and tested for their potentiality to produce extracellular polysaccharide (EPS) using different liquid and solid culture media. 2- Among the 43 isolates the most active producers of EPS were isolates No. E1, H25 and N17. Out of them three isolates were recorded to be the most potent EPS producers. The potentiality of the three organisms to produce EPS was tested in shake cultures (137 rpm) at 25 ± 2°C. 3- The three organisms were characterized through studying their morphological and physiological characteristic. Organisms E1 , Streptomyces lavendulae while H25 identifies as Streptomyces endus either N17 is Streptomyces violaceus 4- Both the quantity and quality of EPS was found to be highly dependent on the producer organism as well as culture conditions. Maximal production of the viscous EPS of the experimental organism either on solid or in shake flask cultures was achieved by cultivating the organism (Streptomyces lavendulae) on a modified starch nitrate medium for 7. The culture medium convenient to the maximal EPS production was composed of the following (g/1): Sucrose, 20.0, CaCl2, 3.0; KNO3, 2, NaCl, 0.5; Mg SO4. 7H2O, 0.5 and 1 ml trace elements solution. The pH was adjusted at 7 with l0mM phosphate buffer. However, for solid cultures the same conditions were applied except that, sucrose was substituted with starch at the same concentration in addition to 20g/l agar. The pH was adjusted initially at 7 – 7.2. Aeration was necessary for both higher viscosity and production of EPS. 169 5- The EPS was- partially purified by successive fractional precipitation with ethanol. At the end of the purification process protein content was reduced. The viscosity of the EPS produced by the experimental organism (E1) increased steadily with the increase of the dissolved EPS. The rheological characteristics were carried out using mixolab and alveograph. The EPS dissolved in salt solutions recorded higher viscosity than those dissolved in water. The EPS solutions revealed strong acidic character which increased with the increase of EPS concentrations; reaching pH 1.2 at 3%. 6- The IR analysis was used for revealing the composition of the produced EPS. The EPS seemed to contain hexoses, uronic acid, pyruvic acid as well as undetermined sugars as compared against algal alginate. 7- The EPS thought to play a role in immune response of white mice to P. aeruginosa (a human pathogen). The results revealed that the EPS at a concentration of 1000 g/ml injected I.P on three successive doses throughout three days induced the immune system and reduced the number of P. aeruginosa (1/10 LD50 = 30 x l06 cells/animal) in the target organs of the experimental mice (lung, liver and spleen). 8- The purified EPS was subjected to cell biology against gastric, cervix, liber, lung and lung adenocarcinoma , It gives a good antitumor activity on gastric, cervix and liver carcinoma compared with the positive control ,also it gives as positive results on lung and lung adenocarcinoma but it was lower than that of the positive control.