Cytochalasin D (CyD) Is a Drug That Binds to the Plus

question 3

Short Answer

Cytochalasin D (CyD) is a drug that binds to the plus end of actin filaments and prevents actin polymerization. Having identified mutations in actin that confer resistance to CyD, a researcher sets out to study the role of the actin cytoskeleton in the invasion of mammalian host cells by two intracellular parasites: the protozoan Toxoplasma gondii and the bacterium Salmonella enterica. She infects wild-type or CyD-resistant host cells with either wild-type T. gondii, CyD-resistant T. gondii, or wild-type S. enterica, each in the presence (+) or absence (-) of CyD, and measures parasite internalization and intracellular proliferation as a result. The findings are summarized in the table below, in which High or Low levels of proliferation are indicated. According to these results, which column (A to C) do you think corresponds to infection with wild-type T. gondii? Which column corresponds to CyD-resistant T. gondii? Which row (D or E) corresponds to the wild-type host? Your answer would be a three-letter string composed of letters A to E only, e.g. ABE.

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Definitions:

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