Cyanobacterial symbiont biosynthesis of chlorinated metabolites fromDysidea herbacea (Porifera)

The tropical marine spongeDysidea herbacea contains large numbers of a symbiotic filamentous cyanobacterium identified on the basis of a detailed ultrastructural study asOscillatoria spongeliae. We report the flow-cytometric separation of the symbiont from the sponge cells, and demonstrate by chemical analyses that a unique group of polychlorinated compounds isolated from the whole sponge tissue is limited to the cyanobacterial filaments, whereas the accompanying sesquiterpenoids are found only in the sponge cells. This is the first demonstration that secondary metabolites ascribed to a sponge are localized in prokaryotic symbiont cells.     

一株地衣芽孢杆菌脲酶生产的发酵优化和酶学性质

对中国南海海绵Halichondria regosa中分离得到脲酶产生菌Bacillus licheniformis B81进行脲酶生产的发酵条件优化;并对其脲酶特性进行测试。通过对基础培养基筛选后,对选定基础培养基进行了Plachett-Bunman重要因素筛选,最终选定的重要因素通过单因素实验得到了最终的培养基配方为:葡萄糖25 g/L,蛋白胨12.5 g/L,牛肉膏5 g/L,酵母粉6.5 g/L,KH2PO42 g/L,NaCl 1 g/L,尿素0.625%(W/V),Ni(NO3)20.006 25%(W/V),H2O 1 L。优化后,使得脲酶的产量提高到了原培养基的170%。菌株所产生的脲酶的最适反应pH为7.0,最适温度为40℃,Pb2+、Cu2+对脲酶活性具有抑制作用。