1. Suppose you suspected that a pathogenic bacteria was the causative agent of A
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Question
1. Suppose you suspected that a pathogenic bacteria was the causative agent of Alzheimer’s disease (a chronic disease that affects human brains). To demonstrate this, you obtained samples from hundreds of patients and you identified a bacterial species that was present in every case. This bacterial species was absent from disease-free controls, and you were able to isolate and cultivate a pure culture of the suspected causative agent. Other people still aren’t convinced! What further steps must be taken to prove that the bacteria causes Alzheimer’s disease? Are there any issues that might prevent you from performing these steps?
2. Suppose you isolated a previously-unknown organism and demonstrated that it was the causative agent of diabetes. What would be the best way to determine how this organism should be classified and what other organisms it is related to? (How best could you figure out where to place this organisms in the phylogenic tree of life?) State what type(s) of test(s) you would run, and how you would interpret the resulting data
EC: Suppose you suspected that a pathogenic bacteria was the causative agent of emphysema (a chronic disease that affect mammalian lungs). To demonstrate this, you obtained samples from hundreds of patients and you identified a bacterial species that was present in every case. This bacterial species was not observed in disease-free controls. A phlegm-covered section from a diseased lung was transferred into a healthy mouse, and the mouse developed the disease. But, other people still aren’t convinced that the bacteria you identified causes emphysema. Why not? What step did you fail to perform? (We decided to skip/omit this question, but maybe still good practice to consider
Fig. 1: Phylogenetic Tree (note: Likely I'l crop this image, to include only a representative section Archaea Euryarchaeota zoa Planctomaetes Actinobacteria E Firmicutes FungiExplanation / Answer
1. The pathogenic bacteria affects the human brain to cause Alzheimer's disease. The causative agent was obtained as pure culture from the diseased individuals. To confirm that the pathogenic bacteria actually casues Alzheimer, the pure culture of causative agent should be introduced in healthy individuals.If they get Alzheimer's disease, it will prove that the pathogenic bacteria causes Alzheimer's disease. The experiment is performed on humans since the bacteria affects human brain, so there is no point in testing it on mice model. Such an experiment cannot be directly performed on humans due to ethical issues.
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