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Sunday, October 2, 2011

2)Specialized transduction


In this type of transduction the virus get adsorbed on the cell wall of bacteria and then it penetrate into the bacterial cytoplasm. It does not cause the breakdown of bacterial DNA. Instead it produce the repressor protein which prevent the transcription of the virus DNA into messenger RNA. At this state, the virus (phage) is called temperate phage. At this state, the virus DNA become integrated into bacteria chromosome (endogenote) . consequently the virus DNA become a segment of bacterial chromosome and then it replicate at the same rate of the bacterial DNA. The virus DNA in this state is known as Prophage.
       A bacterium that carries the virus at prophage stage is known 
      as lysogenic   bacterium as it gets destroyed later when the
     prophage become active  and re-enters into the lytic cycle.   
     These bacteria which suffer infection from temperate phage has
      immune to lysis (breakdown) after reinfection of similar 
     bacteriophage. Sometime this prophage is freed from bacterial 
     chromosome (endogenote) and accidentally it carries adjacent 
     gene from the bacterial chromosome. The prophage containing 
     some gene of bacteria when  infect other bacteria of an 
     appropriate strain ,these genes get transferred to the bacteria 
    chromosome and thus there is recombination of genes of previous
    bacteria and bacteria of appropriate strain.

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