Transcript Microbial Genetics (Micr340) Lecture 8 Conjugation and Transformation

Microbial Genetics (Micr340)
Lecture 8
Conjugation and Transformation
Conjugation
Definitions
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Conjugation - a process in which a plasmid
transfer itself and other DNA elements from
one cell to another
Donor bacterium - a bacterium originally
contains the plasmid
Recipient bacterium - a bacterium that
receives the transferred plasmid
Transconjugant - a recipient cell that has
received DNA as a result of conjugation
Conjugation
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Most naturally occurring plasmids are either:
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self-transmissible
mobilizable
In Gram- bacteria, sex pili facilitate
conjugation
“Promiscuous plasmids” possess transfer
systems that enable them to transfer DNA
between unrelated species
pKM101
Conjugation in Gram
Transfer (tra) genes
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Dtr component
Mpf component
The oriT sequence and function
Mpf function
Mpf function
Mpf function
Pilus formation
Regulation of tra genes
oriT identification
oriT identification
Plasmid
mobilization
Plasmid
mobilization
(continued)
Conjugation in Gram
Triparental mating
Triparental
mating
Chromosome transfer by
plasmids
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Formation of Hfr strains
Transfer of chromosomal DNA by integrated
plasmids
Genetic mapping with Hfr crosses
Transformation
DNA exchange in bacteria
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Three ways
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Conjugation
Transformation
Transduciton
Natural transformation
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Natural competence
Discovery - the Griffith experiment
Gram+ DNA uptake system
Gram- DNA uptake system
Transformation in Streptococcus
pneumoniae
Transformation in Streptococcus
pneumoniae
Transformation
in Haemophilus
influenzae
Artificially induced competence
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Calcium Ion Induction
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transformation by plasmids
transfection - use of viral DNAs or genomic RNA in
transformation
Electroporation