MYCOPLASMA
Mycoplasma are organisms that completely lack a cell
They were discovered by Roux (1898) in pleural fluid of
cattle suffering from pleuropneumonia. The organisms are
often called PPLOs (Pleuropneumonia Like Organisms).
The characteristic features of mycoplasma are
(i) Mycoplasmas are the smallest (0.1-0.5) gm
free-living microorganisms that are so small that they
can easily pass through bacteria-proof filters. These
occur saprotrophically in soil, sewage water and in
dead and decaying organic matter. Some of
also parasiticise plants, animals and human beings
Pathogenic mycoplasmas cause diseases in
hosts.
the
(ii) They are unicellular with plasma membrane as
outermost boundary. The cell membrane is made UP
of protein, lipids and cholesterol.
(iii) DNA is naked (because of the absence of histones
and ribosomes of 70 S type are present.
(iv) Mycoplasmas possess heterotrophic nutrition.
Examples are Mycoplasma gallisepticum,
M. laidlawii. They cause pleuropneumonia in
domestic animals, mycoplasmal urethritis in
humans.
(v) These can survive without oxygen.