Bacterial Gene Therapy

Charlie Scheffta.k.a Pain in my Butt

What is it?

• The Technique using bacteria for direct gene transfer into the tissue, organ, or organism to treat diseases.– This is also called Bactofection

Bacteria are used as vehicles or vectors to transport the genetic info into the cell

Step 1

• Bacteria is entered into cell through endocytosis (eating) and enters cytoplasm

• Transformed bacteria that contain plasmids carrying the transgene are entered into the cell

•Genetically engineered bacteria penetrate into the cells

Step 2

• Once in cell, the bacteria undergo lysis and are destructed when they enter the cytoplasm

•From b to c, the bacteria disappears

Step 3

• They release the DNA plasmids

• Released plasmids then enter the nucleus

• The transgene is expressed by the transcription and translation machinery

Step 4• The transgene product can be expressed two

different ways:– The short oligonucleotides and DNA plasmids can be

released directly into host cells by bacteria

OR– The intercellular bacteria can produce and deliver RNAs

and Proteins

Step 5

• The cell is then changed or corrected

• Then, the corrected proteins are produced

Overview of process

• This is a diagram of Gene Therapy

Types of Bacteria Used

• Salmonella• Probiotic Bacteria• Bifidobacterium Longum

• Modified E. Coli• Shigella• Listeria

Advantages/Disadvantages

• Low cost• Simple production/ delivery• A lot of DNA is delivered

•Not safe• The immune system

could react and cause clearance of bacteria

•Not efficient•Possible side effects• Bacterial strains can

acquire virulence factors back and could lead to serious infections

Probiotic Bacteria

– Natural probiotics help your health– GM probiotics are dangerous– Probiotic bacteria are beneficial bacteria living in our guts

that help maintain the natural balance of organs in the intestines. They are now widely used as food additives for their health-promoting effects. These bacteria have co-evolved with people over millions of years. Their contributions to health and to the development of the host’s (peoples) immune system depend on an intricate web of bacteria-bacteria and bacteria-host relationships that if thrown out of balance will most likely result in disease.

Bibliography

• http://www.nature.com/mt/journal/v17/n5/full/mt200941a.html Molecular Therapy (2009) Yiqi Seow and Matthew J. Wood

• http://nanosingularity.wordpress.com/2007/07/07/bacteria-ferry-nanoparticles-into-cells-for-early-diagnosis-treatment/ Bacteria ferry nanoparticles into cells for early diagnosis, treatment July 7, 2007