Metachromatic granules are found in -a) Diphtheriab) Mycoplasmac) Gardenella vaginalisd) Staphylococcus

Polypmetahosphate / volutin granules Some bacteria contain granules composed of polymetaphosphate. They were first described in spirillum volutans, so they were called as Volutin granules. These granules are also known as Babes Ernst granules or polar bodies or metachromatic granules. These granules stain reddish violet with methylene blue or toluidine blue. These granules are strongly basophilic. In the granules, there is stored phosphate in the form of linear chains of inorganic phosphate. These granules represent intracellular phosphate reserve when nucleic acid syntheis does not occur. The phosphate is incorporated into nucleic acid during the synthesis of the latter. When nucleic acid synthesis is prevented by starvation , the granules accumulate in the cytoplasm. So, volutin metachromatic granules are most frequent in cells grown under conditions of nutritional deficiency (starvation) and tend to disappear when the deficient nutrients are supplied. Volutin metachromatic granules are common in (i) Corynebacteria diptheriae   ii) Mycobacteria  iii) Gardenella vaginalis iv) Spirillum voluants  v) Agrobacterim tumefaciens