Bacteriophage

1. Bacteriophage Lana Evers

2. What is a bacteriophage • A bacteriophage, also known as a phage, is a bacterial virus that attach to their specific hosts and kill them by internal replication and bacterial lysis.

4. History of phage • Bacteriophage inhabited Earth about 3-5 billion years ago • The existence of bacteriophage was not known about until the early part of the 20th century • Was first identified by Frederick Twort and Felix d’Herelle • These two scientists name them this bacteriophages from the Greek word phago which means to eat or devour • At that time, bacteriophage were considered a powerful cure for bacterial infections and were therapeutically utilized throughout the world during the pre-antibiotic era

5. History of Phage • There are no exact numbers however it is estimated that millions of people have been treated with various therapeutic phage preparations • Bacteriophage naturally inhabit various parts of the human body – ie: mouth, skin, gastrointestinal tract, etc. • Humans daily eat many foods containing phage

6. Applications of phage • Gene therapy vehicles • Alternatives to antibiotics • The detection of pathogenic bacteria • Tools for screening libraries of proteins, peptides or antibodies

7. What is Phage therapy • Phage therapy is the therapeutic use of bacteriophages to treat pathogenic bacterial infections.

8. History of phage therapy • Widely used in the 1920’s and 30’s • Large pharmaceutical companies sold products for treatment of Streptococcus and colon bacilli infections • Discovery of antibiotics led to the abandonment of phage therapy products in America and most of western Europe • Phage therapy treatment and research continued in the Soviet Union

9. How does phage therapy work? • Attach themselves to a victim using its tail fibres • After this, the process is different for each phage type • The aim: to get their genetic material, located in the head, inside the bacterium

10. How it works: t4 • Phage’s DNA pushes through tube into cell • Takes control • Brutally stops many vital functions • Forces cell to churn out new virus components – head, tails, fibres • Enzymes dissolve the wall of bacterium from the inside

11. Phage therapy vs. antibiotics

12. Phage therapy

13. Drawbacks of phage therapy • Proponents of phage therapy never succeeded in producing formal proof of efficacy in human treatment • This makes definitive conclusions difficult

14. Methods and purposes

15. Titrations • Pick a plaque from a countable web plate • Create 10-fold titrations Why? • To obtain a titer

16. Ten Plate infections • Infect ten plates to see which one webs out the best Why? • To see which titration webs out

17. Spot test • Make a grid with 10 spots for – one for each dilution • Put a single drop onto each corresponding spot Why? • To see which dilutions give us plaques and contain phage

18. Streak plate • Pick a plaque • Streak across three labeled sections Why? • To see if the plaque contains phage

19. Flood plates • Add phage buffer to webbed plates • Obtain High Titer Lysate (HTL) Why? • To obtain an HTL

20. Restrict & analyze DNA • Digest DNA with restriction enzymes • Electrophorese • Obtain gel image Why? • Compare restrictions with other mycobacteria's

21. My phage - ilsa

22. Results Yield – 0.0035ug/mL Titer – 3.0445x10^9 Size: Head – about 40nm Tail- about 70nm

23. Works cited • www.phagetherapycenter.com • https://www.youtube.com/watch?v=F5xsi40S2Z0 • www.thenakedscientists.com