Definition of retain. transitive verb. 1a : to keep in possession or useb : to keep in one's pay or service; specifically : to employ by paying a retainerc : to keep in mind or memory : remember.
However, some gram- positive bacteria may also have capsules. Examples for gram-negative bacteria with capsules: Escherichia â¦coli, Klebsiella pneumoniae, Salmonella. Examples for gram-positive bacteria with capsules : Bacillus megaterium, Streptococcus pyogenes, Sterptococcus pneumoniae.
Capsules The capsules of many bacilli, including B. anthracis, B. subtilis, B. megaterium, and B. licheniformis, contain poly-D- or L-glutamic acid. Other Bacillus species, e.g., B. circulans, B. megaterium, B. mycoides and B. pumilus, produce carbohydrate capsules. few species, such as Bacillus megaterium, require no organic growth factors; others may require amino acids, B-vitamins, or both. The majority are mesophiles, with temperature optima between 30 and 45 degrees, but some are thermophiles with optima as high as 65 degrees.