Respiratory properties of cysts and vegetative cells of Azotobacter vinelandii

Abstract

The respiratory activity of cysts of Azotobacter vinelandii has been compared with that of vegetative cells. Whole cysts had a much reduced respiratory activity which was less sensitive to KCN. Substrate oxidation rates by membrane preparations from cysts were reduced approximately 10fold and sensitivity to KCN was decreased by a similar factor. Difference spectra of cyst membranes revealed changes in cytochrome content. Cytochrome oxidase d was apparently absent, cytochrome a~ levels were approximately halved whilst those of cytochrome oxidase o were almost doubled. Cytochromes of the b and c-type were present in similar amounts to those in vegetative cells.