Lysogenic Pathway
Lysogenic Pathway - Related Videos
00:43
Lysogenic Cycle of Bacteriophages
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2019
In contrast to the lytic cycle, phages infecting bacteria via the lysogenic cycle do not immediately kill their host cell. Instead, they combine their genome with the host genome, allowing the bacteria to replicate the phage DNA along with the bacterial genome. The incorporated copy of the phage genome is called the prophage. Some prophages can re-activate and enter the lytic cycle. This often occurs in response to a perturbation, such as DNA damage, but can also transpire in the absence of...
09:23
Understanding the Impact of Temperate Bacteriophages on Their Lysogens Through Transcriptomics
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Cited by 2 •
2024
This protocol enables the impact of prophages on their hosts to be revealed. Bacterial cultures are synchronized using conditions that best support the lysogenic state, limiting spontaneous induction. RT-qPCR unequivocally distinguishes prophage-restricted genes and those uncoupled from phage control from those that are expressed during the lytic replication cycle.
03:17
Measuring Spontaneous Phage Induction in Lysogenic Bacteria Over Time
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2026
Source: Krishnamurthi, R., et al. Understanding the Impact of Temperate Bacteriophages on Their Lysogens Through Transcriptomics. J. Vis. Exp. (2024).This video demonstrates the temporal enumeration of spontaneous phage induction in lysogenic Pseudomonas aeruginosa by quantifying viable bacterial cells (CFUs) and infective phage particles (PFUs) over time. By sampling at defined intervals during growth and analyzing both colony and plaque formation, the method reveals when spontaneous induction...
01:16
Viral Replication: Lysogenic Cycle
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2025
The lysogenic cycle is a crucial viral replication strategy that allows bacteriophages to persist within host cells without immediately destroying them. This process is primarily observed in temperate phages, such as bacteriophage lambda (λ), which infects Escherichia coli. The cycle allows the viral genome to persist across bacterial generations while keeping host cells viable.Integration of the Viral GenomeUpon infection, bacteriophage lambda attaches to the bacterial surface and injects its...
01:27
C4 Pathway and CAM
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2019
Most plants use the C3 pathway for carbon fixation. However, some plants, such as sugar cane, corn, and cacti that grow in hot conditions, use alternative pathways to fix carbon and conserve energy loss due to photorespiration. Photorespiration is the process that occurs when the oxygen concentration is high. Under such conditions, the rubisco enzyme in the Calvin cycle binds O2 instead of CO2, which halts photosynthesis and consumes energy. C4 Pathway The C4 pathway is used by plants such as...
FAQs
Once integrated, the prophage is copied whenever the bacterial chromosome is replicated, allowing the viral genome to persist without immediate destruction of the host cell. Its activity is controlled by phage and host factors, which help maintain this state and regulate whether the integrated DNA remains preserved or becomes activated.
Environmental stress can induce the prophage, leading to its excision from the bacterial chromosome and subsequent entry into the lytic cycle. This transition changes the infection outcome from genome preservation to active viral replication and host-cell destruction, making stress an important variable when interpreting phage behavior.
The key difference is the timing and consequence of viral genome activity. During lysogeny, phage DNA remains integrated and is copied with host DNA, preserving the bacterial cell in the short term. In contrast, induction moves the system toward excision and lytic replication, a state associated with active infection and cell destruction.
The pathway can be followed as a sequence: phage entry into the bacterium, integration of phage DNA into the bacterial chromosome, copying of the prophage with host DNA, and possible stress-induced excision. This sequence provides a framework for analyzing whether the infection remains persistent or progresses into the lytic cycle.
An integrated prophage creates a persistent association between viral DNA and the bacterial chromosome. As a result, lysogenic states are relevant to the transfer of genetic traits among bacteria. In infection research, this connection helps explain how phage-associated DNA can influence microbial evolution and alter properties of bacterial populations.
The pathway helps explain the emergence of bacterial virulence factors, including toxin-producing phenotypes. When phage DNA persists within a bacterial genome, it can be associated with changes in traits that affect infection. This makes lysogeny relevant to immunology and infection studies focused on persistent states, microbial evolution, and pathogenic potential.