A: Yes, when S-type bacteria lose their capsules, they become R-type, which is very common. Of course, this is only a "phenotypic variation" and the "genotype" has not changed. For example, Streptococcus pneumoniae can produce capsules in human body, but after artificial culture and passage, the capsules are easily lost and the colonies become R-shaped. In order to ensure that pneumonia can cool down in vitro and produce capsules, we usually use serum, NaHCO3 and CO2 for culture.

As long as it has been done in the clinical laboratory, it is known that it is difficult for bacteria to produce capsules in vitro, and it is necessary to simulate the conditions in vivo.

"The formation of capsules is closely related to environmental conditions. Generally, the capsule is easy to form in animals or media containing serum or sugar, and it is easy to disappear in ordinary media or continuous passage. "

From /view/32 123.htm

2. Can R-type bacteria transform S-type bacteria into R-type bacteria?

From the perspective of Griffith's "transformation" test, this is impossible, but we should not draw a negative conclusion. There is more than one mechanism of bacterial variation.