Calcium and the biological activities of two Streptomyces species isolated from the rhizosphere of soybean plants

Careful examination of the characteristics of both organisms revealed that we are dealing with Streptomyces violaceochromogenes and Streptomyces glaucescens. Calcium chloride decreased the permeability of both organisms as indicated by the low total nitrogen content of their media compared to the controls. Small doses of calcium nitrate suppressed the permeability of S. violaceochromogenes and increased that of S. glaucescens whereas the larger doses were stimulatory for both organisms. Calcium nitrate had similar effects on S. violaceochromogenes only without affecting S. glaucescens. The stimulatory effects of calcium gradually faded with increased concentration. Calcium chloride increased the proteolytic activity in S. violaceochromogenes media; a phenomenon that was apparent in S. glaucescens media only in the case of the larger doses. Calcium nitrate suppressed the proteolytic activity in S. glaucescens media. The cellulolytic activity of both organisms was suppressed by calcium but amylases were initiated in S. glaucescens media. Those of S. violaceochromogenes were arrested with the lower levels of calcium but the larger doses restored or stimulated their activity.