1. Microbial Genetics (Micr340) Lecture 8 Conjugation and Transformation

2. Conjugation

3. Definitions 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

4. Conjugation Most naturally occurring plasmids are either: self-transmissible mobilizable In Gram- bacteria, sex pili facilitate conjugation “Promiscuous plasmids” possess transfer systems that enable them to transfer DNA between unrelated species

5. pKM101

6. Conjugation in Gram- Transfer (tra) genes Dtr component Mpf component The oriT sequence and function

7. Mpf function

10. Pilus formation

11. Regulation of tra genes

12. oriT identification

14. Plasmid mobilization

15. Plasmid mobilization (continued)

16. Conjugation in Gram- Triparental mating

18. Chromosome transfer by plasmids Formation of Hfr strains Transfer of chromosomal DNA by integrated plasmids Genetic mapping with Hfr crosses

19. Transformation

20. DNA exchange in bacteria Three ways Conjugation Transformation Transduciton

21. Natural transformation Natural competence Discovery - the Griffith experiment

22. Gram + DNA uptake system

23. Gram - DNA uptake system

24. Transformation in Streptococcus pneumoniae

26. Transformation in Haemophilus influenzae

27. Artificially induced competence Calcium Ion Induction transformation by plasmids transfection - use of viral DNAs or genomic RNA in transformation Electroporation