A Study On The Antibacterial Activity Investigation Of Human SemenogelinⅠDerived-Peptides At Different PH And Different Concentration Of Zn²⁺

[Objective] To isolate low-molecular-mass antibacterial mixtures from healthy human seminal plasma.[Methods] Semen was obtained by masturbation after at least three days of abstinence from healthy donors. Semen samples were allowed to liquefy at 37℃and then centrifuged at 16000r/min for 10min to separate spermatozoa from seminal plasma. High sensitive antimicrobial activity was measured with radial diffusion assay. Antibacterial activity toward E.coli(ATCC25922) was monitored for each purification steps. The mixtures of seminal plasma samples were applied to Centrifugal ultrafiltration device and then centrifuged at 3000 r/min for 2 hours. Small-molecular parts which showed antibacterial activity and represented the low-molecular-weight cationic fractions of the seminal plasma, were collected. Finally, Small-molecular parts were applied to reverse phase HPLC C4column and reverse phase HPLC C18column. Fractions which showed strong antibacterial activity, were lyophilized and stored at -20℃. The molecular weight of the low-molecule-mass antibacterial mixtures was determined by Matrix-assisted laser desorption/ionization (MALDI)mass spectrometry. [Results] The low-molecular-mass mixtures with obviously higher antibacterial activity, were isolated from the healthy human seminal plasma. Based on the mass spectrometry results, some molecules of RP-HPLC peaks were confirmed to be the semenogelin I derived peptides. [Conclusion] several low-molecular-mass mixtures with obviously higher antibacterial activity, whose mass were lower than 5000, occurred during the liquefication of Human semen. The low-molecule-mass antibacterial mixtures may play an important role in males innate immunity. Semenogelin I derived peptides may be one of the sources of the [Objective] To investigate the antibacterial activity of human Semenogelin I Derived-Peptides at different PH and different concentration of Zn2+. [Methods] On the basis of functional peptide SgI29 and its four derived-peptides (SgI14,SgI19,SgI22 and SgI25)which have antibacterial activity in the past experiments, According to different PH in female genital tract, we established different PH and different concentration of Zn2+ in the experiment. In this environment, the antibacterial activitiy of SgI29 and its derived peptides against Escherichia coli ATCC 25922 and Pseudomonas aeruginosa ATCC 27853 was determined with radial diffusion assay.[Results] SgI29 and its four derived-peptides (SgI14,SgI19,SgI22 and SgI25) had no antibacterial activitiy against Escherichia coli ATCC 25922 and Pseudomonas aeruginosa ATCC 27853 at PH4, but at another PH established in the experiment,SgI29 and its four derived-peptides (SgI14,SgI19,SgI22 and SgI25) had evident antibacterial activitiy. The antibacterial activitiy changed along with their density, the lower, the weaker. The bacterium has not grown when culturing at different concentration of Zn2+. [Conclusion] The PH was an important factor which influences the antibacterial activity of human Semenogelin I Derived-Peptides. Free Zn2+ has evident antibacterial activities against Escherichia coli ATCC 25922 and Pseudomonas aeruginosa ATCC 27853, and the state by which they existed in human semen may affect their antibacterial activities.