Salmonella is closely related to Escherichia. However, Salmonella can neither be infected by lambda phage, nor can it be successfully transfected using lambda DNA. Therefore, this organism is neither a susceptible, nor a permissive host to this virus. Explain the reason for this failure. Please explain in detail. Solution It is true that Salmonella and Escherichia are the gram-negative bacteria but their genetic architecture is different which causes distinct functional proteins for the specific functional. The first step required to infect phage to bacteria is binding process, which comprises a precise interaction between the host cell surface and the virus. However, the virus host interaction critically differs amongst diverse systems. This can be mediated through various cell surface receptors and co-receptors depends on specific virus and host. Like, j protein of lambda phage interact with LamB surface protein of Escherichia coli. The LamB protein is an example of a porin, also called maltoporin, due to its necessary action for growth on limited maltose. But these receptors were absent on the surface of salmonella which restrict the lambda phage salmonella interaction and further transfection of DNA. Few important bacteriophages are there which infect the salmonella eg. Felix01, podophage P22 and phage epsilon15..

1. Salmonella is closely related to Escherichia. However, Salmonella can neither be infected by
lambda phage, nor can it be successfully transfected using lambda DNA. Therefore, this
organism is neither a susceptible, nor a permissive host to this virus. Explain the reason for this
failure. Please explain in detail.
Solution
It is true that Salmonella and Escherichia are the gram-negative bacteria but their genetic
architecture is different which causes distinct functional proteins for the specific functional. The
first step required to infect phage to bacteria is binding process, which comprises a precise
interaction between the host cell surface and the virus. However, the virus host interaction
critically differs amongst diverse systems. This can be mediated through various cell surface
receptors and co-receptors depends on specific virus and host. Like, j protein of lambda phage
interact with LamB surface protein of Escherichia coli. The LamB protein is an example of a
porin, also called maltoporin, due to its necessary action for growth on limited maltose. But these
receptors were absent on the surface of salmonella which restrict the lambda phage salmonella
interaction and further transfection of DNA. Few important bacteriophages are there which infect
the salmonella eg. Felix01, podophage P22 and phage epsilon15.