T4 BACTERIOPHAGE
What is it? It’s history
· Bacteriophages are a type of virus that destroys bacteria.
· Bacteriophages were discovered by British microbiologist ‘Frederick Twort’ in 1915 and by French-Canadian microbiologist ‘Felix d’Hèrelle’ in 1917,who also coined the name “Bacteriophages” meaning bacteria eater.
Structure and Functions
Head(capsid)
o It is a hollow,20 sided geometric shell made up of interlocking protein block.
o Acts as protective container,shielding the genetic material.
Collar
o A small disc located below the head.
o Acts as a neck joint, connecting head to tail.
Sheath
o A hollow,rigid tube surrounding by an outer layer of proteins.It contracts, like a small muscle.
o Functions like hypodermic needle, which contracts the outer sheath to drive the inner tube through the bacterial cell to inject DNA.
Base Plate
o A complex protein platform located at the very bottom of tail.
o Serves as the control site for landing and triggers DNA injection.
Nucleic Acid
o Contains genetic material packed under high pressure.
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o Serves as the instruction manual, with genetic codes,that forces bacterium to manufacture new virus.
How it kills bacteria?
There are 2 pathways
Lytic Cycle
o The phage lands on bacterium surface and injects its DNA inside.
o This viral DNA forces the bacterium to stop its own functions and build new parts, that creates several new phages.
o These newly formed pages release destructive proteins and dissolves cell wall,internal pressure builds up.Bacterium swells, bursts and dies
Lysogenic Cycle
o In this method ,the phage releases its DNA inside the bacterium. This DNA quietly inserts itself directly into the bacterium’s DNA loop.
o The bacterium performs its own function and divides rapidly, as a result the hidden DNA is also copied.
o When the bacterium faces environmental stress like heat or UV light , this stress acts as a alarm clock .The hidden DNA senses danger and curs itself out of bacterium’s chromosomes and switches immediately to lytic Cycle and destroys the bacterium.
Modern life application and its impact
Phage Therapy (medicine)
· Used as targeted treatment to kill antibiotic resistant “superbags” in patients.
Impacts: Saves life where conventional antibiotic fails.
Food Safety (agriculture)
· Sprayed directly onto fresh meats , cheese and produce to kill dangerous pathogens.
Impact : Prevents food p Bioflim clearance (sanitation and industry oisoning outbreaks ,reduce chemical preservation use.
Bioflim clearance (sanitation and industry)
· Applied to medical pipes equipment and industrial water pipes to dissolve slimy protective bacterial layers called bioflims
Impact : Stops hospital acquired infections and Prevents industrial pipe contamination.
