Some Molecular Biological Characters Of A Cyanophage First Isolated In China

In this thesis, the fist cyanophage isolated in China was investigated with regard to the molecular biological characters. Techniques for the large harvest and the electronic microscopy negative staining of the cyanophage were established. The genome library was constructed. Sequencing for some genome fragments was conducted. Furthermore, the sequences were analyzed and compared with the sequence data in GenBank. The results indicated that the cyanophage represented a phage-like shape with head diameter ca.47-52nm and a short tail almost invisible. The cyanophage contained a double-stranded DNA genome at ca. 36.6kb. The genome could be digested only by restriction endonucleases Hind, Accl and Xbal, and was resistant to cleavage by a wide range of other restriction endonucleases. Plasmid pUCIS was used to construct viral genome library. Ten fragments were obtained and some of them were partially sequenced and analysed using GenBank data. Sequence analysis revealed that most of the sequences showed no similarities to the known genes except that only two sequences gave rise to some similarities. In them, one owned a conseved domain of V-ATPase-sub-a, another coded a proline-rich protein, which has multiple phosphate sites.