Lambda phage

Examples of Lambda phage in the following topics:

• Bacteriophage Lambda as a Cloning Vector

  • Enterobacteria phage λ (lambda phage, coliphage λ) is a bacterial virus that infects the bacterial species Escherichia coli.
  • Enterobacteria phage λ (lambda phage, coliphage λ) is a bacterial virus, or bacteriophage, that infects the bacterial species Escherichia coli.
  • Lambda phage consists of a virus particle including a head (also known as a capsid), tail and tail fibers.
  • Usually, a "lytic cycle" ensues, where the lambda DNA is replicated many times and the genes for head, tail and lysis proteins are expressed.
  • Lambda phage has been of major importance in the study of specialized transduction.

• Temperate Bacteriophages: Lambda and P1

  • When undergoing a lysogenic cycle, the phage genome exists as a plasmid in the bacterium, unlike other phages (e.g., the lambda phage) that integrate into the host DNA.
  • At around 93Kbp in length, the genome of the P1 phage is moderately large compared to the genomes of others, like T4 (169Kbp), lambda (48Kbp), and Ff (6.4Kbp).
  • Enterobacteria phage λ (lambda phage, coliphage λ) is a bacterial virus, or bacteriophage, that infects the bacterial species Escherichia coli.
  • Lambda phage consists of a virus particle including a head (also known as a capsid), a tail, and tail fibers.
  • Schematic representation of the insertion of the bacteriophage lambda.

• The Lytic and Lysogenic Cycles of Bacteriophages

  • Lytic phages are more suitable for phage therapy.
  • Some lytic phages undergo a phenomenon known as lysis inhibition, where completed phage progeny will not immediately lyse out of the cell if extracellular phage concentrations are high.
  • Those phages able to undergo lysogeny are known as temperate phages.
  • An example of a bacteriophage known to follow the lysogenic cycle and the lytic cycle is the phage lambda of E. coli.
  • In the lytic cycle, the phage replicates and lyses the host cell.

• Overview of Bacterial Viruses

  • Of these, at least 4950 phages (96%) have tails.
  • The dsDNA tailed phages, or Caudovirales, account for 95% of all the phages reported in the scientific literature, and possibly make up the majority of phages on the planet.
  • Those phages able to undergo lysogeny are known as temperate phages.
  • An example of a bacteriophage known to follow the lysogenic cycle and the lytic cycle is the phage lambda of E. coli.
  • An altogether different phage type, the filamentous phages, make the host cell continually secrete new virus particles.

• Mu: A Double-Stranded Transposable DNA Bacteriophage

  • Bacteriophage Mu, or phage Mu, is a temperate bacteriophage, a type of virus that infects bacteria.
  • All of the known temperate phages employ one of only three different systems for their lysogenic cycle: lambda-like integration/excision, Mu-like transposition, or the plasmid-like partitioning of phage N15.
  • Mu phage transposition is the best known example of replicative transposition.
  • Structural overview of the T4 phage, from the same family (Myoviridae) as Mu bacteriophage.

• Phage Display

  • Phage display is a laboratory tool based on cloning DNA sequences into a phage which presents proteins encoded by that DNA on its surface.
  • When the sub-components of the phage are produced, they self-assemble to form new phage particles.
  • This inherent property of phages is the basis for the phage display technology.
  • Phage display technology is the process of inserting new genetic material into a phage gene.
  • Phage display begins by inserting a diverse set of genes into the phage genome with each phage receiving a different gene.

• Batch Culture of Bacteriophages

  • Bacteriophage cultures require host cells in which the virus or phage multiply.
  • Virus or phage cultures require host cells in which to multiply.
  • An altogether different phage type, the filamentous phages, make the host cell continually secrete new virus particles.
  • Budding is associated with certain Mycoplasma phages.
  • Virus or phage cultures require host cells in which to multiply.

• The Lambda Limit

• Viral Roles in Ecosystems

  • As mentioned, marine viruses are mostly bacteriophages, or phages.
  • Phages therefore are found only within environments that contain bacteria.
  • As a consequence, phages are found almost everywhere.
  • As a rule of thumb, many phage biologists expect that phage population densities will exceed bacterial densities by a ratio of 10:1 or more (VBR or virus-to-bacterium ratio).
  • Phage-ecological interactions are also qualitatively diverse: there are huge numbers of environment types, bacterial-host types, and also individual phage types.

• Double-Stranded DNA Bacteriophages

  • The dsDNA tailed phages, or Caudovirales, account for 95% of all known phages and possibly make up the majority of phages on the planet.
  • The Double-Stranded DNA (dsDNA) tailed phages, or Caudovirales, account for 95% of all the phages reported in the scientific literature, and possibly make up the majority of phages on the planet.
  • The phages have a head of approximately 55 nm in diameter, loaded with genetic material.
  • In the lower micrograph, PAD25 is adhering to bacterial cell debris, and two phages have lost their heads.
  • All phages were classified as Siphoviruses based on their morphology.