Question

In detail, what are the main differences and similarities of pathogenicity islands and bacteriophages? Talk about their role in bacterial pathogenesis.

Answer 1

Bacteriophages.

Obligate intracellular parasites that multiply inside the host by making use of some or all the biosynthetic pathway machinery .

Like most viruses carry only the gentic information needed for nucleic acid and protein coat synthesis .

Each bacteriophage is specific to one type of bacteria .

The infection may or maynot lead to death of bacteria .

Temperate phage can go through one of the two life cycles: lytic amd lysogenic .lytic when growth results in lysis of host and release of progeny phage .

Lysogenic when there is integration between phage and host DNA most of the gene product of this cycle are dormant until they enter lytic cycle.

Pathogenicity island.

The availability of large number of pathogenic genome sequence and their relatives(non pathogenic) leads to identification of novel pathogen specific grnome island .

It also represents a mechanism that contributes for newpathogens appearenxe .

Pathogenicity island carry gene coding for toxins , adhesins ,effectors, modulins, invasins etc leading to bacterial pathogensis.