@article{mbs:/content/journal/micro/10.1099/00221287-23-1-9, author = "Gebicki, J. M. and James, A. M.", title = "The Preparation and Properties of Spheroplasts of Aerobacter aerogenes", journal= "Microbiology", year = "1960", volume = "23", number = "1", pages = "9-18", doi = "https://doi.org/10.1099/00221287-23-1-9", url = "https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-23-1-9", publisher = "Microbiology Society", issn = "1465-2080", type = "Journal Article", abstract = "Summary: Cells of Aerobacter aerogenes growing in a nutrient medium were lysed by 1000 u. penicillin/ml. When the medium contained penicillin and sucrose, bacterial mass continued to increase on incubation, although no further cell division took place. After growth for 3 hr. in the presence of penicillin, all the rod-shaped bacteria were converted to fragile spheroplasts. The internal osmotic pressure of the spheroplasts was estimated by direct counts of the intact cells in solutions containing various concentrations of sucrose, sodium chloride or mixed phosphates. Measurements of optical densities of suspensions were unsuitable for the estimation of the numbers of spheroplasts. Morphological study suggested the existence of a spheroplast cell wall outside the protoplasmic membrane.", }