1. Introduction to Microbiology
Anas Abu-Humaidan M.D. Ph.D.
Lecture 8

2. Horizontal Gene transfer (HGT)

3. Gene transfer/ Conjugation

4. Plasmids
1-200 kbp of circular dsDNA coding for at least one gene. Plasmids can be a Replicon or epitome.
A mechanism for HGT, many are beneficial, classified according to “conjugativity”, compatibility, function.
Important in transfer of antibiotic resistance and virulence factors.
Incompatible plasmids (belonging to the same incompatibility group) normally share the same replication or partition mechanisms and can thus not be kept together in a single cel
Fertility F-plasmids, which contain tra genes. They are capable of conjugation and result in the expression of sex pili.
Resistance (R) plasmids, which contain genes that provide resistance against antibiotics or poisons.
Col plasmids, which contain genes that code for bacteriocins, proteins that can kill other bacteria
Virulence plasmids, which turn the bacterium into a pathogen.

5. Plasmids
OriT (Origin of Transfer) ….. OriC (Origin of Replication)……tra-region (transfer genes) ………… IS (Insertion Elements) 

6. Plasmids
OriT (Origin of Transfer) ….. OriC (Origin of Replication)……tra-region (transfer genes) ………… IS (Insertion Elements) 

7. Gene transfer/ Transduction

8. Bacteriophages

9. Gene transfer/ Transformation

10. Gene transfer/ Transformation

11. Gene transfer/ Transformation

12. Gene transfer/ Transposition

13. Implications of HGT / antibiotic resistance
The resulting S. aureus plasmid encodes resistance to β-lactams, vancomycin, trimethoprim, and gentamycin/ kanamycin/tobramycin antibiotics

14. DNA cloning

15. Further reading and material:
Murray - Medical Microbiology 8th Edition
Section 4: Bacteriology
Chapter 13: Bacterial metabolisim and genetics
Jawetz, Melnick & Adelberg's Medical Microbiology, 26th edition- Section 1: Fundamentals of Microbiology-
Chapter 7:Microbial genetics
Youtube:
Channel: Judith Leatherman
Video : Bacterial genetics part 1
Video : Bacterial genetics part 2