Metachromatic Granule (Volutin) Stains
Metachromatic granules (volutin) are a type of cytoplasmic inclusions found in many bacteria as well as in some fungi, algae and protozoa. The granules are composed mainly of polyphosphates, RNA and proteins. The function of these granules is not clearly understood. Although, speculations have been made as (i) reserve source of food, (ii) phosphate storage structure, (iii) link with energy metabolism and (iv) involvement in nucleic acid synthesis and cell division. The granules are found to be most prominent in old cultures, before starvation occurs
