Microbial Life: Prokaryotes and Protists - Renz Science

Figure 16.1016.11 SCIENTIFIC DISCOVERY: Koch’spostulates are used to prove that abacterium causes a disease Koch’s postulates are four essential conditions usedto establish that a certain bacterium is the cause of adisease. They are1. find the bacterium in every case of the disease,2. isolate the bacterium from a person who has the diseaseand grow it in pure culture,3. show that the cultured bacterium causes the diseasewhen transferred to a healthy subject, and4. isolate the bacterium from the experimentally infectedsubject.© 2012 Pearson Education, Inc.16.11 SCIENTIFIC DISCOVERY: Koch’spostulates are used to prove that abacterium causes a diseaseFigure 16.11 Koch’s postulates were used to demonstrate thatthe bacterium Helicobacter pylori is the cause ofmost peptic ulcers. The 2005 Nobel Prize in Medicine was awarded toBarry Marshall and Robin Warren for thisdiscovery.© 2012 Pearson Education, Inc.16.12 CONNECTION: Bacteria can be used asbiological weaponsFigure 16.12 Bacteria that cause anthrax and the plague can beused as biological weapons.– Bacillus anthracis killed five people in the United Statesin 2001.– Yersinia pestis bacteria– are typically carried by rodents and transmitted by fleas,causing the plague and– can cause a pneumonic form of plague if inhaled.© 2012 Pearson Education, Inc.12