Rapid isolation of bacteroids from soybean root nodules by percoll discontinuous gradient centrifugation

Abstract
A method for the rapid isolation of bacteroids from soybean (Glycine max L. Merr.) root nodules is described. Bacteroids were isolated by Percoll discontinuous gradient centrifugation. Assays of marker enzymes and observation by electron microscopy revealed that the bacteroids obtained were essentially free from contamination by plant cell organelles. The yield of pure bacteroids from 1 g of fresh nodules was approximately 60 mg of bacteroid protein.