一株太湖水域蓝藻噬藻体的分离与鉴定

ISOLATION AND IDENTIFICATION OF A CYANOPHAGE IN LAKE TAIHU

研究首次报道在太湖筛选到的一株感染铜绿微囊藻的噬藻体。在太湖蓝藻水华暴发区域采集水样,经0.22μm微孔滤膜过滤、超滤浓缩后感染对数期的不同株微囊藻,对感染效果明显的进行进一步研究。研究发现M.aernginosa 905有明显感染,用CsCl不连续密度梯度离心的方法对噬藻体进行纯化并研究噬藻体的一步生长曲线。研究发现:在MOI=10 5的感染条件下,该噬藻体感染M.aernginosa的潜伏期为2h,裂解期为4—6h,稳定期为6—12h,裂解量为4 pfu/cell。透射电镜观察此噬藻体头部为二十面体,直径约50 nm,具一很短尾部。此外在不加任何保护剂的情况下,此噬藻体在20℃和80℃下保存感染力丧失,但在4℃条件下保存,其感染活性可维持50d以上。研究为探讨用噬藻体控制蓝藻水华提供了重要基础。

It is the first report on Cyanophage isolated from Lake Taihu and infected Microcystis aernginosa（M.aernginosa）.Water samples were collected from Lake Taihu during bloom season.The water sample was filtered through 0.22 μm polycarbonate membranes and concentrated by tangential flow fitration system,and then was inoculated into exponentially growing cultures of M.aernginosa strains.A further research was done for the algae with obvious infection.The results showed that M.aernginosa 905 was lysed.The lysate was purified through the method of CsCl density gradient centrifugation and one-step growth curve for the cyanophage was also studied.When MOI was 10 5,the latent phase of cyanophage infecting M.aernginosa was 2 hours,the rise phase was 4-6 hours and stabilization was 6-12 hours.The burst size was 4 pfu/cell.The virion with an icosahedral head（nearly 50 nm in diameter） and a short tail was observed under the transmission electron microscopy.The cyanophage had not only the specificity of species but also the specificity of strains.It could only infect M.aernginosa 905.In addition,the infection activity was lost when the cyanophage was stored at 20 ℃ and 80 ℃ without cryoprotectants,but the infection activity maintained over 50 days at 4 ℃.The above findings provide a potential method for biological control of algae bloom by cyanophage.