Bacterial transduction

BACTERIAL TRANSDUCTION
PRESENTED BY SAIRA FATIMA
ROLL NO:31
MSc 4 [2018-2020]
Department of MicroBiology & Molecular Genetics
University of the Punjab
Lahore, Pakistan

1. BACTERIAL TRANSDUCTION PRESENTED BY SAIRA FATIMA ROLL NO:31 MSc 4 [2018-2020] Department of MicroBiology & Molecular Genetics University of the Punjab Lahore, Pakistan

2. DEFINATION • The transfer of genetic material from one cell to another cell by a bacteriophage is called Transduction . • Transduction has been found to occur in variety of prokaryotes , including certain species of Bacteria : Escherichia , Pseudomonas , Salmonella , Staphylococcus , etc. • The bacteriophage containing the bacterial DNA is called transduced DNA .

3. DISCOVERY Transduction was discovered by Zinder and Lederberg while searching for conjugation in salmonella typhimurium . Lederberg- Zinder experiment - After placing two auxotrophic strain of Salmonella on opposite side of the U-tube, the researches recovered prototrophs from the side with the LA-22 strain, but not from the containing the LA-2 strain. These initial observations led to the discovery of the phenomenon called transduction

4.  U – Tube Experiment

5. BACTERIOPHAGE A bacteriophage is a virus that infects and replicate within a bacterium .

6. TYPES OF BACTERIOPHAGE  • VIRULENT : Capable of causing infection and eventually destruction and death of the bacterial cell . These follow LYTIC CYCLE . Example : T4 host E.coli . • TEMPERATE: Does not cause destruptic infection instead phage DNA incorporated into bacterial DNA and replicate (LYSOGENIC)and after some cycle become virulent cause lysis . Example : lamda phage .

7. TYPES OF TRANSDUCTION  There are TWO types of transduction: 1. Generalized transduction • A DNA fragment is transferred from one bacterium to another by a lytic bacteriophage(virulent) which carrying donor bacterial DNA due to an error . 2. Specialized transduction • A DNA fragment is transferred from one bacterium to another by a temperate bacteriophage which carrying donor DNA along with phage genome due to an error .In this a phage insert a genome at specific site.

8. STEPS OF GENERALIZED TRANSDUCTION A lytic bacteriophage infect a susceptible bacterium . The phage genome enters into the bacterium . The genome directs a bacterium’s metabolic machinery to manufacture bacteriophage components and enzyme . Occasionaly , a bacterial genome get into a phage coat by mistake and the bacteriophage released . When this phage having bacterial DNA infect another bacterium , the previous bacterial DNA incorporated into new bacterial genome forming recombinant DNA .

9. STEPS OF SPECIALIZED TRANSDUCTION A temperate bacteriophage infect a susceptible bacterium and inserts its genome into bacterium . T he DNA of a bacteriophage, incorporated into the genome of a bacterium . It is called PROPHAGE . 3 .Occasionally during spontaneous induction , a small piece of the donor bacterial DNA is picked up as part of the phage genome . As the bacteriophage replicates , the segment of bacterial genome also replicates along with phage genome . When this phage infect another bacterium , the donor DNA along with phage genome inserted into a recipient bacterial genome forming recombinant DNA .

10. ABORTIVE TRANSDUCTION • Transduction in which the DNA fragment from the donor bacterium(transduced DNA) is not integrated in the genome of the recipient bacterium and when the latter divides, is transmitted to only one of the daughter cells.

11. SIGNIFICANCE OF TRANSDUCTION  • It transfer genetic material from one cell to another and alter genetic characteristic . • For Example , In specialized transduction, a cell lacking ability to metabolize galactose could acquired ability . • It shows evolutionary relationship between the prophage and host bacterial cell. • Prophage can exist in a cell for a long period suggest a possible mechanism for viral origin of cancer . • It provides a way to study the gene linkage .

12. THANK YOU