Heterozygous Biotechnology Of Antibiotics Neomycin And 68 Active Metabolites Of Fungal Chemical Research

PART 1 ISOLATION AND STRUCTURE IDITIFICAITON OF MINOR COMPONENTS OF SHENGJIMYCINSShengjimycins are a group of hybrid 4"-O-acylspiramycins which were produced by a genetically engineered strain WSJ-1 bearing 4"-O-isovaleryl-transferase gene. Shengjimycins have showed strong activity against gram-positive bacteria and some gram-negative bacteria. It is more active thanclinically used 4"-O-acetylspiramycin and erythromycin in vivo. Shengjimycins are hopeful bioengineered antibiotics for clinical usage.The first part of this dissertation is mainly on the chemical study of minor components of Shengjimycins.HPLC analysis demonstrated that Shengjimycins were multicomponent antibiotics. The major components, Shengjimycin A₁, B₁ and E₁ which proved to be 4"-O-isovalerylspiramycin â…¢, â…¡ and â…  previously, has accounted for about 55% of the mixture. Some other 4"-O-acylspiramycins such as 4"-O-acetyl-spiramycin, 4"-O-propionylspiramycin, 4"-O-butyrylspiramycin and few spiramycins have also been found. Total content of 4"-O-acylspiramycins has reached to about 90% of the crude product.By means of continuous countercurrent distribution, basic silica gel column chromatography , preparative TLC and medium pressure liquid chromatography, monitored by TLC and HPLC, five minor components, Shengjimycin C₂, B₃, B₂, B₀ and A₀ were isolated from Shengjimycins crude powder, the contents of them were 2.6%, 6.2%, 3.3%, 1.5% and 0.5%, respectively. Shengjimycin B₂ is a complex of B_2α and B_2β isomer. Based on careful analysis of UV, IR, SI-MS, FAB-MS, GC-MS, ¹H-NMR, ¹³C-NMR, ¹H-¹H COSY, the structures of Shengjimycin C₂, B₃, B_2α, B_2β, B₀ and A₀ were elucidated as 4"-O-propionylspiramycin â…¡, 4"-O-propionylspiramycin â…¢, 4"-O-butyrylspiramycin â…¡ , 4"-O-isobutyrylspiramycin â…¡, 4"-O-(3-methyl-2-butenoyl) spiramycin â…¡ and platenomycin A₁, respectively. Shengjimycin B₀ and B_2β are two novel hybrid spiramycin antibiotics.