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Expert: Florence M Rollwagen - 3/12/2009


Question
I wanted to ask that other than transformation being a method of introducing Dna into prokaryotic cells what is the meore efficient method of introducing Dna into prokaryotic cells. i'm confused between, transduction, tranfection and conjugation.

Thankyou

Answer
Hi Mariam:  Thanks for your question.

These processes are easily confused and my students have a lot of trouble with them as well:

Transduction is mediated by phages.  When a phage infects a bacterium, it inserts its DNA into the host genome.  When the phage leaves the host, it can take some of that host DNA with it and infect another cell.

Conjugation requires direct contact between bacteria.  This requires mating types in bacteria. Part of the male (F+) DNA is passed to the female (F-) bacteria.

Transformation occurs when bacteria take up DNA from their environment.  This is illustrated in the famous Griffiths experiment with Strep pneumoniae which you probably studied in your class.

Here’s a website:
http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/A/Avery.html

Hope this helps!  Write back if you have more questions.

FM Rollwagen, PhD  

Biology

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Florence M Rollwagen

Expertise

I can answer questions in biology, microbiology and immunology on the undergraduate or graduate level. I can also address medical and health concerns regarding alternative medicine, autoimmune diseases (lupus, MS) liver disease and intestinal problems.

Experience

I have over 20 years experience in research and teaching at the medical/graduate level, and 5 years teaching college biology and microbiology. My expertise is in microbiology and immunology, specifically the biology of cytokines and soluble immune response modifiers. I also carried out original research in blood substitutes and shock/trauma.

Organizations
American Association of Immunologists (AAI) American Association for the Advancement of Science (AAAS)

Publications
Journal of Experimental Medicine, Journal of Immunology, Cytokine, Shock, Experimental Hematology

Education/Credentials
BS biology 1966 MS biology 1968 PhD immunology 1979

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