In 1965, Jon Beckwith and Ethan Signer devised a method of obtaining specialized transducing phages carrying the lac region. They knew that the integration site, designated att80, for the temperate phage φ80 (a relative of phage λ) was located near tonB, a gene that confers resistance to the virulent phage T1: tonB att80 They used an F ′ lac+ plasmid that could not replicate at high temperatures in a strain carrying a deletion of the lac genes. By forcing the cell to remain lac+ at high temperatures, the researchers could select strains in which the plasmid had integrated into the chromosome, thereby allowing the F ′ lac to be maintained at high temperatures. By combining this selection with a simultaneous selection for resistance to T1 phage infection, they found that the only survivors were cells in which the F ′ lac had integrated into the tonB locus, as shown here: tonB F lac att80 This result placed the lac region near the integration site for phage φ80. Describe the subsequent steps that the researchers must have followed to isolate the specialized transducing particles of phage φ80 that carried the lac region
Bacterial Genomics
The study of the morphological, physiological, and evolutionary aspects of the bacterial genome is referred to as bacterial genomics. This subdisciplinary field aids in understanding how genes are assembled into genomes. Further, bacterial or microbial genomics has helped researchers in understanding the pathogenicity of bacteria and other microbes.
Transformation Experiment in Bacteria
In the discovery of genetic material, the experiment conducted by Frederick Griffith on Streptococcus pneumonia proved to be a stepping stone.
Plasmids and Vectors
The DNA molecule that exists in a circular shape and is smaller in size which is capable of its replication is called Plasmids. In other words, it is called extra-chromosomal plasmid DNA. Vectors are the molecule which is capable of carrying genetic material which can be transferred into another cell and further carry out replication and expression. Plasmids can act as vectors.
In 1965, Jon Beckwith and Ethan Signer devised a
method of obtaining specialized transducing phages
carrying the lac region. They knew that the integration
site, designated att80, for the temperate phage φ80 (a
relative of phage λ) was located near tonB, a gene that
confers resistance to the virulent phage T1:
tonB att80
They used an F
′
lac+ plasmid that could not replicate at
high temperatures in a strain carrying a deletion of the
lac genes. By forcing the cell to remain lac+ at high
temperatures, the researchers could select strains in
which the plasmid had integrated into the chromosome,
thereby allowing the F
′
lac to be maintained at high
temperatures. By combining this selection with a
simultaneous selection for resistance to T1 phage
infection, they found that the only survivors were cells in
which the F
′
lac had integrated into the tonB locus, as
shown here:
tonB F
lac att80
This result placed the lac region near the integration site
for phage φ80. Describe the subsequent steps that the
researchers must have followed to isolate the specialized transducing particles of phage φ80 that carried the lac
region
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