Lambda phage

About: Lambda phage is a research topic. Over the lifetime, 1609 publications have been published within this topic receiving 84675 citations. The topic is also known as: Enterobacteria phage lambda.

Molecular analysis of the recombination junctions of lambda bio transducing phages.

Abstract: To examine the mechanism of recombination involved in the formation of specialized transducing phage during the induction of bacteriophage λ we have determined the nucleotide sequences of the recombination junctions of λbio phages. The results indicate that abnormal excision takes place at many sites on both bacterial and phage genomes and that the recombination sites have short regions of homology (5–14 bp). Some of the sequences of the recombination sites were similar to the consensus sequences of DNA gyrase-cleavage sites and repetitive extragenic palindromic (REP) sequences. These results showed that abnormal excision is a type of illegitimate recombination. The possible involvement of DNA gyrase in this recombination is discussed.

Cloning and characterization of the Escherichia coli chromosomal region surrounding the dnaG Gene, with a correlated physical and genetic map of dnaG generated via transposon Tn5 mutagenesis.

Abstract: A 24 kilobase pair region of the E. coli chromosome surrounding the dnaG gene has been cloned and characterized. A lambda phage library was constructed by ligating a Sau3A( decreases GATC) partial DNA digest of the entire E. coli chromosome into the lambda BamHI(G decreases GATCC) cloning vector charon 28. Partial digestion was performed to generate overlapping chromosomal fragments and to allow one to walk along the chromosome. This library was probed with a nick-translated plasmid (pRRBl) containing the rpoD gene, which maps adjacent to dnaG at 66 min. Four bacteriophages: lambda 3, lambda 4, lambda 5, lambda 6 that hybridized to the probe were isolated from the 2,500 plaques screened. One phage recombinant lambda 4, was shown to contain the dnaG gene. Three recombinant plasmids containing dnaG: pGL444, pGL445, pBS105, were constructed via subcloning of lambda 4 using different restriction of fragments. Plasmids pGL444 and pBS10 5 were subjected to transposon Tn5 mutagenesis and 88 Tn5 inserts into the cloned region were isolated. The location of the Tn5 inserts were mapped by restriction enzyme analysis of the plasmids and the insertion mutations were checked for ability to complement of dnaGts chromosomal marker at nonpermissive 40 degrees C. In this manner a correlated physical and genetic map of dnaG was determined. A large number of Tn5 inserts map to a specific 900 b.p. region which we propose may be involved in the regulation of dnaG gene expression.

Effect of infection with phage lambda on the synthesis of protein, rna and dna in escherichia coli.

Abstract: Summary: Delay in deoxyribonucleic acid (DNA) synthesis after use of ultraviolet radiation to induce Escherichia coli lysogenic for phage λ was due to the irradiation procedure; the same delay was found in non-lysogenic bacteria exposed to the same dose of radiation. After infection with phage λ c or λ V in 0.02 m-MgSO4, DNA synthesis began without delay when complete medium was added. During vegetative development of phage in induced bacteria, 81--89% of the DNA synthesized was accounted for in the phage progeny, indicating that host DNA synthesis is much diminished and may be completely inhibited. Mature phage particles arose soon after the appearance of serum blocking power (SBP) and endolysin activity. Induced bacteria synthesized up to 15 times more SBP than was incorporated into complete phage particles: the excess SBP was not sedimented at 40,000 g (unlike phage particles), but about half was sedimented at 90,000 g, the rest remaining in the supernatant fluid. Whilst protein and RNA synthesis in infected or induced bacteria was initially similar to that in the control, there was a marked decrease of synthesis in the second half of the latent period.