Extraction Of Antimicrobial Peptides From African Ostrich And Investigation Its Biological Function

The experiments studied on African ostrich, and extracted the antibacterial peptides from it's skin To detect the traits of the peptide, It were tested on the antibacterial activities and chemotactic activity in cells in vitro. and the animal test was done to detect the effect on immun-organ growth and function of chickling. It was few studies on the antibacterial peptides from African ostrich , only the osp-1and osp-2 and osp-3 from leukocyte of African ostrich were found. Two parts. were included in my studies.Part I :Separation and extraction of the antibacterial peptides from skin of African ostrich and examining it's antibacterial activites and chemotaxis.Separation and distillation of the antibacterial peptides from skin of African ostrich:After cutting the skin to pieces and wheting them, then proteins were extracted under gentle agitation for 24 hours in 5 % acetic acid at 4℃. The extraction was centrifugated and centrifugate again after adjusted PH. The peptides from skin were collected when the acid soluble proteins in the supernatant of centrifugalization were passed through Sephadex G-100. Agarose diffusion assay method was used to detect antimicrobial activity of the collection. The micromolecule proteins which showed antibacterial activities were dried under vacuum..Minimal inhibitory concentration (MIC) method was employed to determine the content of antimicrobial peptides which including the drier resuspended in sterile distilled water,eluant after Sephadex G-100 and the extraction .The results were found that the MICs of drier and eluant were not seen, however the MIC of extraction was 3.2-6.4mg/ml, the exact MIC of the antibacterial peptide was 1-3 mg/ml except some giant molecule proteins.Chemotaxis tests were proceed in agarose gel to examining the chemotactic activity in cells in vitro. The resukts showed that it was not clear about the chemotactic activity of drier of skin antibacterial peptide in cells.The two tests of MIC and chemotaxis suggested that the spacial structure of the antibacterial peptide was complicated and affected by the factors such as low temperature and time. So, the antibacterial activity and chemotactic activity were disappeared.Part II Effect on the immun-organ of chickling by the antibacterial peptides from skin of African ostrich. Focusing on the limping ostrich and making animal models: 280 Hai LanBai male chicken with 1 day were randomly divided into 2 groups: test group and control group. The chicken in test group were fed by basal diet supplemented with 1ug/ml antibacterial peptides in skin respectively. 1,4,7,10.17 days later, five chicken of each group was weighted and killed respectively. Then, main immune organs including thymus, spleen and bursa of fabricus were weighed and their indexes which are the ratio of the weight of organ(mg) to that of body weight(g) were calculated. The results of the studies, compared with the control group, showed that the group fed with 1ug/ml antibacterial peptides in skin had significantly increased on the thymus index and the bursa index( P < 0.05) at 7days. and the spleen index had more significant increase(P<0.01) with 7 days. So, antibacterial peptides in skin can enhance chickens immune organs growth..In order to study on the effect on the immune organs of chickling through feeding them antibacterial peptides from skin, a naphthy I acid esterase (ANAE) enzyme staining was used. Results suggested that, the numbers of ANAE~+ in thymus, spleen were higher (P<0.05) in test group than that in control group at 7 days. In addition, the numbers of ANAE~+ in bursal was more significant increased (P<0.01). so, It is assumed that antibacterial peptides operates by an activation of the immune system.Enhance, Results of the experiments of part II showed that antibacterial peptides from skin could enhance immune organs growth and cell immunity, especially at early phase of animal growth.