A novel phage genome integrated into a plasmid in Bacillus thuringiensis strain AF101

Related Experiment Video

Updated: Sep 12, 2026

Site-specific Bacterial Chromosome Engineering: ΦC31 Integrase Mediated Cassette Exchange (IMCE)
08:21

Site-specific Bacterial Chromosome Engineering: ΦC31 Integrase Mediated Cassette Exchange (IMCE)

Published on: March 16, 2012

K Kanda1, Y Tan, K Aizawa

  • 1Institute of Biological Control, Faculty of Agriculture, Kyushu University, Fukuoka, Japan.

Journal of General Microbiology
|November 1, 1989
PubMed

Insights

Bacillus thuringiensis strain AF101 harbors a plasmid (pAF101) that contains the integrated genome of the J7W-1 phage. This phage genome integration into a plasmid was also observed in other Bacillus thuringiensis strains.

Area of Science:

  • Microbiology
  • Molecular Biology
  • Genetics

Background:

  • Bacillus thuringiensis (Bt) is a Gram-positive bacterium known for its insecticidal properties.
  • Bt strains often harbor plasmids that carry genes for toxins and other functions.
  • Phages can infect bacteria and integrate their genomes into the host's DNA.

Purpose of the Study:

  • To investigate the nature of a plasmid (pAF101) in Bacillus thuringiensis strain AF101.
  • To determine the relationship between the plasmid and an induced phage (J7W-1).
  • To explore the phenomenon of phage genome integration into plasmids in B. thuringiensis.

Main Methods:

  • Plasmid curing experiments using ethidium bromide.
  • Phage induction and isolation.
  • Southern blot hybridization to analyze DNA.
  • Restriction pattern comparison of plasmid and phage DNA.

Main Results:

  • Ethidium bromide treatment induced the J7W-1 phage from B. thuringiensis strain AF101.
  • The J7W-1 phage genome hybridized exclusively with pAF101 DNA.
  • pAF101 contains the complete J7W-1 phage genome and a plasmid-specific region.
  • Phage genome integration into a plasmid was also observed in B. thuringiensis subsp. israelensis.

Conclusions:

  • The J7W-1 phage genome is stably integrated into the pAF101 plasmid in B. thuringiensis strain AF101.
  • This integration represents a novel mechanism of phage-plasmid interaction.
  • Phage genome integration into plasmids may occur in other B. thuringiensis strains.

More Related Videos

Using Coculture to Detect Chemically Mediated Interspecies Interactions08:29

Using Coculture to Detect Chemically Mediated Interspecies Interactions

Published on: October 31, 2013

Phage-Mediated Genetic Manipulation of the Lyme Disease Spirochete Borrelia burgdorferi09:01

Phage-Mediated Genetic Manipulation of the Lyme Disease Spirochete Borrelia burgdorferi

Published on: September 28, 2022

Related Concept Videos

Lytic Cycle of Bacteriophages01:30

Lytic Cycle of Bacteriophages

Bacteriophages, also known as phages, are specialized viruses that infect bacteria. A key characteristic of phages is their distinctive “head-tail” morphology. A phage begins the infection process (i.e., lytic cycle) by attaching to the outside of a bacterial cell. Attachment is accomplished via proteins in the phage tail that bind to specific receptor proteins on the outer surface of the bacterium. The tail injects the phage’s DNA genome into the bacterial cytoplasm. In the lytic replication...
Lysogenic Cycle of Bacteriophages00:43

Lysogenic Cycle of Bacteriophages

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...
Bacterial Transformation01:33

Bacterial Transformation

In 1928, bacteriologist Frederick Griffith worked on a vaccine for pneumonia, which is caused by Streptococcus pneumoniae bacteria. Griffith studied two pneumonia strains in mice: one pathogenic and one non-pathogenic. Only the pathogenic strain killed host mice.Griffith made an unexpected discovery when he killed the pathogenic strain and mixed its remains with the live, non-pathogenic strain. Not only did the mixture kill host mice, but it also contained living pathogenic bacteria that...
Viral Replication: Lysogenic Cycle01:16

Viral Replication: Lysogenic Cycle

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...
DNA Bacteriophages01:26

DNA Bacteriophages

Bacteriophages, or phages, are viruses that specifically infect bacteria, utilizing their genetic material to hijack host cellular machinery for replication. DNA bacteriophages employ single-stranded DNA (ssDNA) or double-stranded DNA (dsDNA) genomes. These phages exhibit diverse replication strategies and host interactions, influencing their ecological roles and applications in biotechnology and medicine.ssDNA BacteriophagesssDNA phages, with their small genomes, utilize unique strategies to...
Production of Biopesticides01:18

Production of Biopesticides

Biopesticides offer a sustainable alternative to chemical pesticides, utilizing microbial agents to control agricultural pests. Bacillus thuringiensis (Bt) is a widely employed bacterium known for its potent insecticidal activity. Bt biopesticides are favored for their specificity to insect pests, minimal environmental impact, and natural degradability.Mechanism of Bt Toxin Action Bt produces insecticidal crystal (Cry) proteins during its sporulation phase. These proteins form parasporal...