Using a Macrophage‐like Cell Line,researchers Infected One Set of Petri

Multiple Choice

Using a macrophage‐like cell line,researchers infected one set of petri dishes with wild‐type Listeria,and,as a negative control,infected another set with a Listeria mutant that was unable to enter cells.At specific time points,the cells were fixed and prepared for electron microscopy.Four hours after infection,they observed that many of the wild‐type Listeria in the cytoplasm ______________.

A) were surrounded by a cloud of tubulin
B) were surrounded by a cloud of actin
C) were surrounded by a cloud of keratin
D) had long "tails" of short randomly oriented actin filaments that appeared to have extended from one pole of the Listeria
E) had long "tails" of short randomly oriented microtubules that appeared to have extended from one pole of the Listeria