What is lysogeny in microbiology?

Lysogeny, type of life cycle that takes place when a bacteriophage infects certain types of bacteria. In this process, the genome (the collection of genes in the nucleic acid core of a virus) of the bacteriophage stably integrates into the chromosome of the host bacterium and replicates in concert with it.

What determines the balance between lysogeny and the lytic cycle?

27.19 What Determines the Balance between Lysogeny and the Lytic Cycle? The delayed early stage when both Cro and repressor are being expressed is common to lysogeny and the lytic cycle. The critical event is whether cII causes sufficient synthesis of repressor to overcome the action of Cro.

What factors drive the bacteriophage λ toward lysis or lysogeny?

In λ, the ‘decision’ to enter lysogeny is driven by genetic compatibility (for example, host attB integration sites), host physiological state (for example, nutrient depletion increases lysogeny) and phage density (for example, higher MOIs increase lysogeny) (Casjens and Hendrix, 2015).

What phage protein is necessary to maintain a stable Lysogen?

Two phage proteins, Int and CI, are required to form stable lysogens. Int allows the integration of the phage genome into the bacterial chromosome, and CI represses the two early phage promoters to prevent any lytic phage gene expression.

What are the advantages of Lysogeny?

Lysogeny is of benefit to the virus, allowing the genetic material to persist in the absence of a virus manufacture. Lysogeny can also be beneficial to the host bacterium. The primary benefit to bacteria occurs when the integrated viral DNA contains a gene that encodes a toxin.

Why is Lysogeny important?

Lysogeny protects a virus from environmental factors (e.g., inactivation by UV sunlight or proteolytic digestion) that may damage the viral capsid or nucleic acid while on occasion conferring “immunity” to the host via gene expression that prevents coinfection by other viruses (Jiang and Paul, 1996).

What is the basis for animal virus classification?

Classification of viruses. Animal viruses can be classified by the nature of the nucleic genome (ie, DNA or RNA). In addition, viruses are often called by their morphological features. For instance, according to the existence of envelope, it can be called either an enveloped virus or naked (nonenveloped virus).

What is an example of a lysogenic virus?

Streptococcus pyogenes, produce a pyrogenic exotoxin, obtained by lysogenic conversion, which causes fever and a scarlet-red rash, scarlet fever. Certain strains of Clostridium botulinum, which causes botulism, express botulinum toxin from phage-tranduced genes.

Who determine the sequence of lambda phage?

Explanation: The phage DNA molecule, unlike the bacterial plasmid DNA, exists usually in a linear conformation and DNA is a duplex molecule. 3. Who determined the sequence of Lambda phage? Explanation: The exact sequencing of lambda phage of 49 kb was done with Sanger sequencing method in 1982.

Why is lambda DNA used as a marker?

Lambda DNA (48,502 bp) may be used as a molecular weight size marker during nucleic acid gel analysis following digestion with a restriction enzyme (such as HindIII). Lambda DNA can also be used as a substrate in restriction enzyme activity assays.

What are the two important outcome of Lysogeny?

It was concluded that lysogenic bacteria perpetuate latent phages as ‘prophages’ in a repressed state. They do not secrete phages. Spontaneously or after induction, the prophage enters a vegetative phase, new phages are produced, and the bacterium dies.

How does a lambda phage virus attach to a bacteria cell?

During infection, the phage particle recognizes and binds to its host, E. coli, causing DNA in the head of the phage to be ejected through the tail into the cytoplasm of the bacterial cell. Usually, a “lytic cycle” ensues, where the lambda DNA is replicated and new phage particles are produced within the cell.

What is the medical definition of lysogeny?

Medical Definition of lysogeny : the state of being lysogenic

How does the lysogeny of a virus work?

Lysogeny refers to a process whereby a virus that specifically infects a bacterium, a bacteriophage (which means “devourer of bacteria”), achieves the manufacture of copies of its deoxyribonucleic acid ( DNA ) genetic material by integrating the viral DNA into the DNA of the host bacteria .

Why is lysogenic cycle important to bacteriophages?

These proteins are required to enter the lysogenic cycle, and so when cro-protein concentration goes high the lambda phage initiates the lytic cycle. Lysogeny is probably of major significance to temperate bacteriophages because most bacteria isolated from natural habitats are lysogenic for one or more bacteriophages. 1.

What happens to lysogeny if more CI is made?

If more cI is made, lysogeny continues. If cro is made, the process of viral assembly (i.e., the lytic cycle) begins. The lytic cycle can be triggered by events that damage the host bacterium, including exposure to environmental stressors (e.g., ultraviolet radiation exposure).