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Food-Borne Illness-Causing Bacteria May Find Protection in Protozoa

Applied and Environmental Microbiology, Mar-2005

Neighbors can sometimes be a bad influence on each other — especially when they are one-celled microscopic animals called protozoa and certain bacteria that are commonly linked to food-borne illnesses, like Salmonella.

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Active Reading Questions

  1. This article reports research indicating that some protozoa consume bacteria and concentrate them into vesicles that are then released and may enhance the bacteria’s ability to cause illness if they are consumed on produce. Both the bacteria and the protozoa are single-celled organisms, but they are very different cell types. Which of the following explains why bacteria and protozoa are so different?
    a) Bacteria and protozoa are actually similar in many ways; both are prokaryotes
    b) Bacteria are prokaryotes that do not contain membrane-bound structures; protozoa are eukaryotes and have membrane-bound structures like vesicles.
    c) Bacteria are plant cells and protozoa are animal cells.
    d) Bacteria can cause disease, and protozoa cannot cause disease.
  2. Scientists believe that groups of bacteria packaged inside a membrane-bound vesicle may actually help those bacteria survive. How does the presence of a membrane assist in the survival of what is inside that membrane?
    a) A membrane forms a physical protective barrier.
    b) A membrane helps regulate water loss.
    c) A membrane allows only certain chemicals to enter and leave.
    d) all of the above
  3. The vesicle membrane is a plasma membrane. Using what you know about the plasma membrane, describe what characteristics a sanitizing solution would need to break up a vesicle full of bacteria?
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