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Expert: Florence M Rollwagen - 7/14/2008


Question
1. How is it possible for an organism to grow on starch agar if it does not hydrolyze starch?

2. Why does one stab the peptone iron agar instead of inoculating only the surface?

Thanks VERY much

Answer
Hi Jill:  Thanks for your questions.

Starch agar is usually composed of nutrient agar with starch added.  Organisms can grow on it w/o the use of starch because the media provides the necessary carbon and energy sources.

Peptone iron agar is used to detect the ANAEROBIC production of H2S by bacteria.  It is inoculated by stab so that the organisms deep in the agar can grow in the absence of oxygen.

I hope this answer has helped you.  Please write back if you have more questions.

FM Rollwagen, PhD

Biology

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Volunteer

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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