2. Introduction
Characteristics
Structure
Life cycle & viral infection
The role of
bacteriophage t4 in
cholera and diphtheria
Significance
3. Assalamualaikum mam good morning to everyone.
It is honour to me to present here something and thank you mam for
that
I want to prenent the t4 bacteriophage on this day
4. Virus is an infective agent that typically consists of a nucleic acid
molecule in a protein coat, and is able to multiply only within the living
cells of a host.
Viruses have few or no enzymes of their own they don’t contain
Ribosome.
To multiply, viruses must take over the metabolic machinery of the host
cell. That’s why they are called obligatory intracellular parasites.
Viruses had infected bacteria are known as bacteriophage (from the
Greek “to eat bacteria”).
Bacteriophage T4 is a virulent phage. It is also known as lytic phage.
5. Bacteriophage T4 (phage T4) is a virulent phage; it uses the
metabolic machinery of the host cell to produce progeny viruses
and kills the host in the process.
Bacteriophage T4 is a large & dsDNA virus.
T4 bacteriophage infect the colon bacillus Escherichia coli
bacteria.
it does not have a probacteriophage form,
The T4 chromosome is approximately 168,800 base pairs long
and contains about 150 characterized genes.
6. • Large virus with a complex
protein
coat
–At least 36 different types of
proteins make up the coat
Over 150 genes, 189 kb
genome of ds DNA
• The tail has an inner hollow
tube called core, surrounded
by a contractile sheath which
consists of 24 annular rings.
• The distal end of the tube is
connected to a hexagonal
basal plate with spike or tail
spin at each corner.
• Six long, flexible tail fibers
also arise from the basal
plate.
7.
8. The role of bacteriophage t4 in
cholera and diphtheria
Cholera is caused by the bacterium Vibrio
cholera. However, V. cholera does not cause the disease
unless it is infected with a lysogenic T4 bacteriophage
carrying the gene for cholera toxin. Cholera toxin is what
causes the severe diarrhea.
Corynebacterium diphtheriae, the bacterium that causes
diphtheria. must carry a phage containing the gene for
diphtheria toxin to cause the disease.
9. Phages may be useful in killing bacteria that are resistant to antibiotics
or in cases where the antibiotic has difficulty in reaching the bacteria
phages are specific—a specific phage will only kill a few strains of
bacteria. Thus, they leave the native bacteria flora intact.
T4 bacteriophage also use in the Recombinant DNA Technology.
In the past, phages were also used by some to treat infections.
