Spheroplasts of Marine Bacteria induced by the Action of Penicillin

Abstract

SEVERAL species of marine bacteria which are characterized by osmotic dependence have been induced to form spheroplasts by the action of penicillin added to cultures growing optimally in a nutrient broth prepared with sea water. Two factors indicated the likelihood of obtaining this result. First, recent papers^1–3 have contained results indicating that the internal osmotic pressure of marine bacteria and halophiles was equal to, or less than, the external environment; consequently, spheroplasts of these bacteria should be stable in the growth medium. Second, the media, in particular those containing sea water, are characterized not only by a high osmotic pressure but also by a high content of magnesium ions, a characteristic of solutions used to stabilize penicillin-induced spheroplasts of Gram-negative bacteria⁴. The techniques for inducing spheroplasts of marine bacteria and a comparison of the osmotic fragilities of cells and spheroplasts of one species are described briefly in this communication.