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Institute of Technology of Cambodia Department of Chemical and food technology . Identification of Cyanophage Ma-LBP and Infection of the Cyanobacterium M. aeruginosa from an Australian Subtropical Lake by the Virus ( Stephen & Peter, 2004). Prof.: Dr. Hul Seingheng
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Institute of Technology of Cambodia Department of Chemical and food technology Identification of Cyanophage Ma-LBPand Infection of the Cyanobacterium M. aeruginosafrom an Australian Subtropical Lake by the Virus( Stephen & Peter, 2004) Prof.: Dr. HulSeingheng Subject :General Microbiology Group 2 : DYSI Nora EK Pichmony HakRany HE Ravy Horn chanrithy Academic year 2010-2011
Key terms • Cyanophage : • phage that infects to cyanobacteria • Virus specific to cyanobacteria • Infection: • Lysis:dissolution or destruction of cells, such as blood cells or bacteria, as by the action of a specific lysin that disrupts the cell membrane.
Why was this research conducted? • Toxic cyanobacteria are common seasonal inhabitants of subtropical lakes in Queenland, Australia. ( late autumn and early spring) It could be because of : • Natural control by cyanophage • Environmental factors : influence the ability of virus to infect, lyse the host.
Objectives of research • to determine whether Cyanophage influence on the abundance of M. aeruginosa blooms. • Identify the Cyanophage Ma-LBP.
Material and Methods Materials • Sampling site : Lake Baroon, South EastQueenland, Australia
Material and Methods Materials • Field sample : - collected in March, April, June and July 2001 - from intake tower , north and south swimming pool( at the surface, at 3, 6 and 9m depths) Water samples mixed before further subsampling • Host growth medium : B-12 medium for isolated and grow M.aeroginosa.
Material and Methods (con’t) • Methods
Results • M.aeruginosa growth rate
Results • Lysis assays • The more VLPs that were present at the start of the incubation, the more and faster the host population decreased.
Results • Observing viral infection and lysis Viral burst size : • -28 cyanophage per cell • -each cycle of replication cycle 11.2h • Cell wall rupture • Cytoplasm leakage • C. Whole cells
Results • TEM studied to characterize the cyanophage T7-like morphology with short geometries tail : family Podoviridae
Discussion • Important finding: the quantitive demonstration of cyanophage that are infective for M.aeruginosa • TEM of Cyanophage Ma-LBP is same as TEM picture of Podoviridae
Discussion • Infection, lysis and immunity • Host decrease 95% within 6 days when Cyanophage Ma-LBP in original sample=0.23% from the sampling No bloom can form , if nothing interfere with the Cyanophage ability
Discussion However…..After the lysis assays • host cells (after 95% reduction). Then we add Cyanophage again. • This acclimated host cells attained natural population densities in 3 weeks with a resistance to the Cyanophage Ma-LBP. The host may have simply become resistant
Conclusion • Control of bloom formation • Cyanophage presence possibly suppressed M.aeruginosa abundance. • Cyanobaterial blooms may results from condition in the lake that both favor host growth and prevent viral infection and lysis.
Recommendation • Research aims • to understand physical and chemical factors that might control toxic cyanobaterial blooms • Should also.. • consider the factors might interfere with the binding, infection, and lysis of the host’s cyanophage.
Reference • Tucker, S. & Pollard, P. (2005).Applied and Environmental Microbiology: Identification of Cyanophage Ma-LBP and Infection of the CyanobacteriumMicrocystisaeruginosa from an Australian Subtropical Lake by the Virus.71:2. pp629-635. Doi: 10.1128/AEM.71.2.629-635.2005
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