phage in dairy 3rd group
Post on 07-Jul-2015
134 Views
Preview:
TRANSCRIPT
Muhammad Saleem kalhoro
Damodar Dhakal
Thura Kyaw
Yi Win
A virus that specially infects bacteria.
Ancestral Times- Fermented Milk products.
1.Organoleptic test 2. PH measurement
3. Titration
Lactococcus lactis, was the first infected
Invented by Whitehead and Cox (1935)
LAB like lactobacilus, leuconostoc,
pediococcus, and streptococcus for yoghurt,
cheese and butter milk production.
Virulent phages-largest economic losses of
dairy factories.
Attachment of bacteriophage in host cell
Entry of phage DNA and degradation of host
DNA
Synthesis of viral genomes and proteins
Assemble to form head, tail and tail fibre
Release- cell swells and bursts
Denaturation
1. Sample heated to 94 degree
2. Separate single strand
3. Base for stage 2
Annealing
1. Tempr lowered to 54 degree
2. Synthetic DNA fragments are added as primer
3. Form ionic bond with the template
Extension
1. Again heated to 72 degree
2. Polymerase enzyme is added
3. Bind the primer-templete hybrid
4. Synthesis of DNA
These three steps are repeated to produce the more DNA
Starter Culture
(Selected strains)Fermentation Vat
•Bacteriophage
attack
•Enhance fermentation
•Improve flavor texture
•Culture
multiplication
•Several fold
decrease in
bacterial culture
•lysis of infected host
•Delay of Acidification
•Quality changes
•Failure of fermentation
Bacteriophage-Total absence is impossible.
Host specific (so big collection of culture is
needed)
If phage detected then milk directed to
byproducts production, buttermilk, smp.
Adsorption interference,
1.production of extracellular polysaccharides
2.Bind in the capsular form- physical barrier.
3.↑capsule thickness than phagetail-↓phage
infection
DNA injection blocking
1.Calcium dependent cell wall
3.Translocation of host DNA
4. Prevents entering cell cytoplasm
restriction/modification,
Introducing two enzymes system
Site specific-restriction endonuclease, helps in
the digestion of phage DNA
Methylase-protects host cell by modifying DNA.
abortive infection,
Encompasses a range of mechanisms that
interfere with
Genome replication
Transcription
Translation
Packaging or assembly of phages.
top related