Dissertation > Biological Sciences > Botany > Plant ecology and biogeography > Aquatic plant science

The Isolation and Identification of Cyanophage from Taihu Lake

Author LiuLu
Tutor GuoZongLou; HuangPu
School Zhejiang University
Course Agricultural Engineering
Keywords algal bloom Microcystis aeruginosa cyanophage Molecular Biology
CLC Q948.8
Type Master's thesis
Year 2013
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In recent years, algal blooms frequently occur in fresh water due to the nutrient enrichment from sewage, agricultural fertilizers and industrial run-off into waterways. Algal blooms are considered to be a threat to the quality of the water system. It is important to control the blue-green algae blooms. Cyanophage plays a potential role in controlling the algal blooms for high host-specificity.Water samples were collected to isolate cyanophage when algae blooms outbreaked in Taihu Lake. Cyanophage existence was confirmed through color changes, and cyanophage were expanded stably and purified. The Biological characteristics including heat stability, storage condition, sensitivity to chloroform and UV light were studied. The structure change of M. aernginosa905and structure of cyanophage were observed by electron microscope. The nucleic acid of cyanophage was analysed by restriction enzyme, while the protein was analysed by SDS-PAGE. This research provides a theoretical basis for biological control algae.The main results were as follows:1. M. aeruginosa905cells were infected by the cyanophage isolated in4days. This cyanophage were expanded stably and purified.2. With the biological characteristics analysis, the best preservation conditions is4℃in dark. The cyanophage was sensitive to UV light, and M. aeruginosa905was still infected by the cyanophage without light. The cyanophage was sensitive to chloroform for capsule membrane existence.3. With the electron microscope, the M. aernginosa905cell shape was changed dramatically the normal circular into irregular form. The phage possesses an icosahedral head with a diameter of ca.50nm and a non-contracted tail.4. The nucleic acid of cyanophage is a double-stranded circular DNA virus and was digested by Hinc Ⅱ, Pst Ⅰ and Sam I with a clear restriction pattern. The results of the SDS-polyacrylamide gel electropHoresis showed that the cyanophage isolate contains at least9polypeptides.

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