The MaMV-DC cyanophage,which infects the bloom-forming cyanobacterium Microcystis aeruginosa,was isolated from Lake Dianchi,Kunming,China.Twenty-one cyanobacterial strains were used to detect the host range of MaMV-DC...The MaMV-DC cyanophage,which infects the bloom-forming cyanobacterium Microcystis aeruginosa,was isolated from Lake Dianchi,Kunming,China.Twenty-one cyanobacterial strains were used to detect the host range of MaMV-DC.Microcystic aeruginosa FACHB-524 and plaque purification were used to isolate individual cyanophages,and culturing MaMV-DC with cyanobacteria allowed us to prepare purified cyanophages for further analysis.Electron microscopy demonstrated that the negatively stained viral particles are tadpole-shaped with an icosahedral head approximately 70 nm in diameter and a contractile tail approximately 160 nm in length.Using one-step growth experiments,the latent period and burst size of MaMV-DC were estimated to be 24–48 hours and approximately 80infectious units per cell,respectively.Restriction endonuclease digestion and agarose gel electrophoresis were performed using purified MaMV-DC genomic DNA,and the genome size was estimated to be approximately 160 kb.Sodium dodecyl sulfate polyacrylamide gel electrophoresis(SDS-PAGE)analysis revealed four major structural proteins.These results support the growing interest in using freshwater cyanophages to control bloom-forming cyanobacterium.展开更多
The objective was to visualize a variety of marine bacteriophage and identify unique structural features that set them apart from terrestrial phages. Phages were plaque isolated and characterized using atomic force mi...The objective was to visualize a variety of marine bacteriophage and identify unique structural features that set them apart from terrestrial phages. Phages were plaque isolated and characterized using atomic force microscopy. Bacteriophage infecting cyanobacteria synechococcus that exhibits a novel structural feature not previously reported for any other phages were observed. These cyanophages have up to four, 450 nm long, multi-stranded, complex helical fibers that emanate from either the base plate and/or the collar of the phage particle, origins of shorter fibers on well-studied phages such as T4. The flexible fibers terminate at their distal ends in multiple bulbs of diameter 30 nm composed of 20 to 30 closely associated proteins. Bulbs form one of two distinctive patterns, or tassels. Most commonly, the arrangement is a 3 + 1 pattern of three consecutive bulbs at the very end with a forth lying upstream, separated from the terminal three by a gap of 135 nm. In other populations the fibers terminate in 5 consecutive bulbs. It is proposed that the novel appendages may be involved in host cell searching and recognition in a marine environment.展开更多
基金National Natural Science Foundation of China(grant nos.31072239,31270213)Knowledge Innovation Program of the Chinese Academy of Sciences(grant no.KSCX2-EW-Z-3)StateKey Laboratory of Freshwater Ecology&Biotechnology Program(grant no.2011FBZ12)
文摘The MaMV-DC cyanophage,which infects the bloom-forming cyanobacterium Microcystis aeruginosa,was isolated from Lake Dianchi,Kunming,China.Twenty-one cyanobacterial strains were used to detect the host range of MaMV-DC.Microcystic aeruginosa FACHB-524 and plaque purification were used to isolate individual cyanophages,and culturing MaMV-DC with cyanobacteria allowed us to prepare purified cyanophages for further analysis.Electron microscopy demonstrated that the negatively stained viral particles are tadpole-shaped with an icosahedral head approximately 70 nm in diameter and a contractile tail approximately 160 nm in length.Using one-step growth experiments,the latent period and burst size of MaMV-DC were estimated to be 24–48 hours and approximately 80infectious units per cell,respectively.Restriction endonuclease digestion and agarose gel electrophoresis were performed using purified MaMV-DC genomic DNA,and the genome size was estimated to be approximately 160 kb.Sodium dodecyl sulfate polyacrylamide gel electrophoresis(SDS-PAGE)analysis revealed four major structural proteins.These results support the growing interest in using freshwater cyanophages to control bloom-forming cyanobacterium.
文摘The objective was to visualize a variety of marine bacteriophage and identify unique structural features that set them apart from terrestrial phages. Phages were plaque isolated and characterized using atomic force microscopy. Bacteriophage infecting cyanobacteria synechococcus that exhibits a novel structural feature not previously reported for any other phages were observed. These cyanophages have up to four, 450 nm long, multi-stranded, complex helical fibers that emanate from either the base plate and/or the collar of the phage particle, origins of shorter fibers on well-studied phages such as T4. The flexible fibers terminate at their distal ends in multiple bulbs of diameter 30 nm composed of 20 to 30 closely associated proteins. Bulbs form one of two distinctive patterns, or tassels. Most commonly, the arrangement is a 3 + 1 pattern of three consecutive bulbs at the very end with a forth lying upstream, separated from the terminal three by a gap of 135 nm. In other populations the fibers terminate in 5 consecutive bulbs. It is proposed that the novel appendages may be involved in host cell searching and recognition in a marine environment.
