A study was made of the structure of Bac. subtilis and Listeria monocytogenes protoplasts by the method of scanning electron microscopy. The mechanism of protoplast formation in Gram-positive bacteria and in spheroplasts of Gram-negative bacteria proved to differ. A loss of the rigid form of the cell, round protrusions on cell surface, and an escape of the cytoplasm through the ruptured cell wall in some one place was noted in case of protoplasts. Individual cells can coalesce with one another with the formation of shapeless masses. The formation of small spheroid bodies by budding, and also a division of protoplasts by constriction was described.
Bacillus subtilis Listeria monocytogenes