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.
The capsule is not synthesized by the closest relatives of B. anthracis, i.e., B. cereus and B. thuringiensis, and this criterion can be used to distinguish the species. Cell Walls The variability of cell wall structure that is common in many Gram-positive bacteria does not occur in the genus Bacillus. 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.