VMC 311: Systematic Veterinary Bacteriology and Mycology (2+1)

MORPHOLOGY

• Mycoplasmas are the smallest and most pleomorphic microorganism.
• They occur as cocci, spirals, flaments and rings. The characteristic feature is the complete absence of cell wall or cell wall precursors such as muramic acid and diaminopimelic acid.
• They stain poorly with Gram's stain (gives Gram –ve). Gives better resuts with Giemsa and other Romanowsky stain.
• The method of reproduction is not fully understood. But some divide by binary fission, or by budding.
• Some have a reproductive cycle by the development within the filaments of elementary bodies and their subsequent release by fragmentation and disintegration of the filaments.
• The minimal reproductive unit is about 0.3 µm in d.m. but because the cells are pliable they are able to pass through a 0.22 µm membrane filter.
• Dark field and Phase contrast microscopy are recommended for studying the morphology of Mycoplasma.
• M. mycoides has a galactan capsule. They are generally non- motile and non-spore forming.