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21 terms

Expt 33 - BACTERIOPHAGE TITRATION

STUDY
PLAY
Viruses
obligate intracellular parasites
Viruses
has to infect host cell to replicate
Viruses
host specific - infect only one type of animal
Virion
consists of nucleic acid, RNA ORRRRR DNA (not both)
surrounded by capsid (protein coat)

may have envelope around capsid
Life cycle of virus
attachment to host cell
release nucleic acid in host cell
replicates (produce viral components)
assemble viral components into virions
release of virions
Bacteriophage / phage
virus that infects bacteria
lysis
release of new virus particles from host cells
lysis in broth culture
partial to complete clearing of the suspension due to destruction of bacterial cells
plaque assay
quantity of bacteriophages in a broth
temperate phages
capable of lysogeny
lysogeny
viral genome integrates in host cell's chromosome
lysogeny
viral genome is replicated with host cell chromosome during cell division
lysogeny
no virions produced
viral genome is induced to enter a lytic cycle
conditions: nutritional deprivation, or exposure to UV radiation
direct cell to produce virions
phage lambda
infects Escherichia coli
suspension is incubated
for phage attachment and infection of host cells

soft agar is added. hardens
no phage
lawn of bacteria (cloudy)
phage
clearing in lawn
clearing in lawn
viral plaque caused by the cycle of lysis/reinfection/lysis
concentration of phage
plaque forming units per milliliter (pfu/ml)
phage titer
#plaques x dilution correction