All of the following are true statements about bacterial S-layers EXCEPT:
A) They are commonly found in Gram-positive cells as well as in archaea.
B) They are a crystalline layer consisting of protein or glycoprotein.
C) They present a formidable physical barrier to predators or parasites.
D) They are found in bacteria freshly isolated from natural sources.
E) They are found in bacteria isolated from laboratory cultures.

Question

Quizplus · Accepted Answer

S-layers are indeed found in bacteria freshly isolated from natural environments, as stated in option D, but they are often lost when these bacteria are grown under laboratory conditions, making option E the incorrect statement. This is because the selective pressures present in natural environments, which necessitate the presence of S-layers for protection and survival, are absent in laboratory cultures.

All of the Following Are True Statements About Bacterial S-Layers