Study on application of cyanobacterial vector

自养微型浮游生物是一类影响海洋和湖泊中生物地球化学过程并影响初级生产物命运的微生物。为了了解噬藻体的生态作用及其对沿海海洋环境中蓝藻水华和营养物质循环的影响，了解噬藻体的感染性以及噬藻体与其宿主海洋蓝藻微微型浮游生物之间的相互作用至关重要。本研究以噬藻体为载体，以分子生物学为工具，分离了一株新的噬藻体（S-KM 1株），并研究了其对鹿儿港湾富含藻蓝蛋白的聚球藻（KFM 001株）的季节感染性。我们发现，噬菌体滴度范围从检测不到750000个细胞/毫升，在秋季，并开始增加约一周后，发生的聚球藻秋季水华。在秋季的几个月里，噬菌体数量以一种降低宿主丰度水平的方式波动，显示出大约一周的滞后。我们从0开始计算。0055%至2.在秋季聚球藻水华期间，每天有1%的宿主群体被噬菌体裂解。同时，我们还观察了它们的负染透射电镜照片和噬菌体DNA的特征，以及与其它噬菌体的分子系统发育关系。作为分子生物学的工具，我们研究了这些噬藻体作为载体的应用。但是，由于噬菌体的宿主范围很窄，感染性不强等原因，噬菌体的应用并不成功。噬菌体不具有耐保存能力。研究发现，噬藻体的寄主范围广、感染性强、耐保存能力强，是其作为媒介应用的重要条件。

Autotrophic picoplankton are a group of microorganisms that affect biogeochemical processes and influence the fate of primary production in oceans and lakes. To understand the ecological role of cyanophage and its effect on blooming of cyanobacteria and nutrients cycling in the coastal marine environment, it is critical to understand cyanophage infectivity and the interactions that occur between the phage and its host marine cyanobacterial picoplankton. In this study, we examined to apply of cyanophage for a vector as a tool of molecular biotechnology.We isolated a new virulent cyanophage (strain S-KM1), and here have investigated its seasonal infectivity of cyanophage, phycoerythrin-rich Synechococcus sp. (strain KFM001) in Kagoshina Bay. We found that the phage titers ranged from undetectable to 750000 cells/ml in autumn, and began to increase about one week after the onset of the Synechococcus autumn bloom. During the autumn months, the phage numbers oscillated in a fashion that minored levels of host abundance, showing a lag of about one week. We calculated that from 0. 0055% to 2. 1% of the host population per day was lysed by the phage during a Synechococcus bloom in autumn. This suggests that lyic phages have a noticeable efect on regulating the densities of marine Svnechococcus populations.Also, we showed their transmission electron micrography of negative-stained and the characteristics of phage DNA and molecular phylogenetic relationship between our phage and others. As a tool of molecular biotechnology, we examined to application of those cyanophage for a vector. But, it is not succeed for the reason that the phage have a very narrow host range and not so strong infectivity. The phage do not have an tolerant capacity to preservation. It was found throug this study that wide host range, strong infectivity and tolerant capacity to preservation were important to application of those cyanophage for a vector.