lysogenic cycle

Examples of lysogenic cycle in the following topics:

• Mu: A Double-Stranded Transposable DNA Bacteriophage

  • Bacteriophage Mu is a temperate bacteriophage that uses DNA-based transposition in its lysogenic cycle.
  • 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.

• Overview of Bacterial Viruses

  • Bacteriophages may have a lytic cycle or a lysogenic cycle, and a few viruses are capable of carrying out both.
  • In contrast, the lysogenic cycle does not result in immediate lysing of the host cell.
  • At this point they initiate the reproductive cycle, resulting in lysis of the host cell.
  • As the lysogenic cycle allows the host cell to continue to survive and reproduce, the virus is reproduced in all of the cell's offspring.
  • An example of a bacteriophage known to follow the lysogenic cycle and the lytic cycle is the phage lambda of E. coli.

• Bacterial Transduction

  • Transduction happens through either the lytic cycle or the lysogenic cycle.
  • If the lysogenic cycle is adopted, the phage chromosome is integrated (by covalent bonds) into the bacterial chromosome, where it can remain dormant for thousands of generations.
  • If the lysogen is induced (by UV light for example), the phage genome is excised from the bacterial chromosome and initiates the lytic cycle, which culminates in lysis of the cell and the release of phage particles.
  • The lytic cycle leads to the production of new phage particles which are released by lysis of the host.
  • If bacteriophages undertake the lytic cycle of infection upon entering a bacterium, the virus will take control of the cell's machinery for use in replicating its own viral DNA.

• Temperate Bacteriophages: Lambda and P1

  • In virology, temperate refers to the ability of some bacteriophages to display a lysogenic life cycle.
  • In virology, temperate refers to the ability of some bacteriophages (notable coliphage λ) to display a lysogenic life cycle.
  • 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.
  • Usually, a "lytic cycle" ensues, where the lambda DNA is replicated many times and the genes for head, tail, and lysis proteins are expressed.
  • The host can be termed a lysogen when a prophage is present.

• Virulent Bacteriophages and T4

  • The lytic cycle is one of the two cycles of viral reproduction, the other being the lysogenic cycle .
  • A key difference between the lytic and lysogenic phage cycles is that in the lytic phage, the viral DNA exists as a separate molecule within the bacterial cell, and replicates separately from the host bacterial DNA.
  • The location of viral DNA in the lysogenic phage cycle is within the host DNA, therefore in both cases the virus/phage replicates using the host DNA machinery, but in the lytic phage cycle, the phage is a free floating separate molecule to the host DNA.
  • The lytic cycle is a six-stage cycle.
  • T4 is capable of undergoing only a lytic lifecycle and not the lysogenic lifecycle.

• Plasmids and Lysogeny

  • The lysogenic cycle is key to ensure the transmittance of bacteriophage nucleic acids to host bacterium's genome.
  • Lysogenic cycles are utilized by specific types of viruses to ensure viral reproduction, but they also need the second major method of viral reproduction, the lytic cycle, as well.
  • The lytic cycle, considered the primary method of viral replication, results in the actual destruction of the infected cell.
  • The lytic cycle is characterized by the breakdown of the bacteria cell wall intracellularly.
  • Schematic of lysogenic and lytic cycle utilized by viruses to ensure viral reproduction.

• Batch Culture of Bacteriophages

  • In contrast to virion release, phages displaying a lysogenic cycle do not kill the host but, rather, become long-term residents as prophage.

• General Features of Virus Replication

  • The life cycle of viruses differs greatly between species but there are six common basic stages:
  • Some viruses undergo a lysogenic cycle where the viral genome is incorporated by genetic recombination into a specific place in the host's chromosome.

• Single-Stranded DNA Bacteriophages

  • A number of exceptions to this life cycle are known.
  • Lysogenic species, which encode integrases, exist within this family.
  • Although the majority of species in this family have lytic life cycles, a few may have temperate life cycles.

• Bacteriophage Lambda as a Cloning Vector

  • Usually, a "lytic cycle" ensues, where the lambda DNA is replicated many times and the genes for head, tail and lysis proteins are expressed.
  • However, under certain conditions, the phage DNA may integrate itself into the host cell chromosome in the lysogenic pathway.
  • The host can be termed a lysogen when a prophage is present.