Effects Of PSET152 On Fortimicin A Production In Micromonospora Sp. 40027

The Micromonospora which can produce antibiotics with Various types of structures belongs to the rare actinomycetes. In terms of out-put of new antibiotics, Micromonospora is more than Streptomyces for the moment. so, Micromonospora, as Searching for new antibiotics and other bioactive substances people pays more attention to it.It also has an enormous research potential.The article mainly talked about the Micromonospora sp. 40027 strain and Micromonospora sp. 40027:: pSET152 strain. By comparing of bioactive of their fermentation culture and fermentation product, this paper studied the effects of plasmid pSET 152 with heterologous genes acc(3)IV on production, structure and function of fortimicin A.Mycelium is disrupted by ultrasonic method and freezing- thawing method. The results show that ultrasonic method is much better for mycelium disruption, and bioactive substances of Micromonospora sp. 40027 strain intracellular contain fortimicin A by TLC detection. The bioactive substances of extracellular is higher than intracellular.According to the study on the fermentationin broth of Micromonospora sp. 40027 strain, the results show that the 12th hour and 42th hour are the best time of seed culture and fermentation culture for Micromonospora sp 40027 strain.Bacteriostatic activity of Micromonospora sp. 40027 strain and Micromonospora sp.40027: : pSET 152 strain are compared during active strains and fermentation period. The results show that Micromonospora sp. 40027 strain has higher bacteriostatic activity than Micromonospora sp. 40027: : pSET 152 strain.Separation and purification of the active component from the fermentation broth of Micromonospora sp.40027 stains were studied too.The results indicated that the maximum absorption capacity of fotimicin A from Micromonospora sp. 40027 stains are 6 times to the volume of ion exchange resin; 0.5N ammonia eluent is 4 times to the volume of ion exchange resin. Theirs extracts are basically determined on the basis of analysis of the Thin Layer Chromatographic (TLC).The most effectly developing solvent is composed of chloroform, methanal and concentrated ammonia(1:2:1). Using refractive index detector(RID) and evaporative light scattering detector(ELSD) detect standard of fortimicin A for chromatographic analysis.The results show that ELSD is more effective than RID. The condition of ELSD determination: the mobile phase is the mixture of 0.2 mol/L trifluoroacetic acid and methanol(95: 5) at the rate of 1.0mL/min with the temperature of the drift tube 40℃and the injection volume of 20μL, high pure nitrogen atomizing gas pressure of 350 kPa. Under these conditions, 1mg/mL fotimicin A standard retention time is 7.20min.The extras of fotimicin A of Micromonospora sp. 40027:: pSET152 strain and Micromonospora sp. 40027 strain are detected by HPLC,Their respective retention time is 7.31,7.35 min, the proportion of peak area of fotimicin A are 11.9%,12.3%. It shows that their fermentation product contains the same amount of fotimicin A. The results show the difference between the antibacterial activity is not only produced by fotimicin A content , but also the plasmid pSET152 with acc(3)IV had a passive effect on activities of fotimicin A. so it lead to decrease antibacterial activity.