Mycoplasma: Useful Notes on Mycoplasma (With Diagram) | Microbiology

(PPLO-Pleuropneumonia like organisms and L-forms)

It has been established now that smallest cell, or free living organisms, is not a bacterium; it is so minute and could not be seen except through an electron microscope.

Louis Pasteur discovered the existence of this organism, which is the causative agent of pleuropneumonia, a contagious disease of cattle. But Pasteur could not isolate culture or see it under a microscope because it was too small.

There are several kinds of this organism, but the smallest is about 0.1 micron in diameter and is known as PPLO (Pleuropneumonia like organisms) or Mycoplasma. In size these cells are like viruses in that they can pass through a fine-pored filter; then can however, grow in a nonliving medium, as do bacteria. Their internal organization is also bacterialike. They contain plasma membrane, ribosomes, complete metabolic machinery with some 40 known enzymes and an ill-defined nuclear apparatus lacking a nuclear membrane.