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.
Capsule is 0.2Âµm thick viscus layer firmly attached to the cell wall of some capsulated bacteria. If capsule is too thick it is known as slime. Slime layer are loosely attached to cell wall and can be lost on vigorous washing and on sub culture. Composition of capsule: 98% water and 2% polysaccharide or glycoprotein/ polypeptide or both.