Conjugación

Conjugation
DNA from a donor cell is transferred to a recipient cell through a conjugation tube
The ability to conjugate is located on the F-plasmid. F+ cells act as donors- F- Ceññs act asrecipients.
F+/F- conjugation: F factor replicates off a single strand of DNA. New strand goes trhpugh pili to recipient cell. New strand is made double stranded. If entire F-plasmid crosses, thenrecipient cell becomes F+, otherwise nothing happens.
Conjugation with Hfr: Hfr cell (high Frequency recombination) cells have F-plasmid integrated into the Chromosome. Integration into theChromosome is unique for each F-plasmid strain. When F-plasmid material is replicated and sent across pili, Chromosomal material is included. When chromosomal material is in recipient cell,recombination can occur:
Recombination is double stranded. Donor genes are recombined into the recipient cell. Corresponding genes from recipient cell are recombined out of the chromosome and reabsorbed bythe cell.
Interrupted Mating Mapping
1.- Allow conjugation to start: Genes closest to the origin of replication site (in the direction of replication) are moved through the pili first.
2.-After a set time, interrupt conjugation: Only those genes closest to the origin of replication site will conjugate. The long the time, the more that is able to conjugate.
3.- Notice which genesare recombined: Genes that recombine are within X distance (conjugation time-distance) of the origin of replication.
Conjugation Mapping
Using different strains of F-plasmids and the interruptedmating technique, it can be determined the order of genes on the Chromosome.


Transformation
Uptake of naked DNA molecule from remains of one bacterium (donor cell) by another bacterium(recipient cell)

Bibliography:
Nc State University. “recombination in bacteria”. 01/11/2011. URL: http://www.cals.ncsu.edu/course/gn411/emigh411/conjugation.pdf

Bacterial conjugation animation...