SOME OBSERVATIONS ON THE SO-CALLED 'CYSTITES' OF THE GENUS ARTHROBACTER

Abstract

The development and significance of the enlarged 'cystite' forms of Arthrobacter globiformis and Arthrobacter pascens have been investigated. It was found that pure populations of cystites could be grown by introducing inoculum from a rich medium into a minimal medium. The enlarged cells produced under these conditions ranged from two to four times the size of the small coccoid forms typical of old cultures of Arthrobacter. When these cystite forms were transferred to an adequate medium, initial growth appeared like the germ tubes of fungal spores. Continued growth resulted in the formation of cross walls with subsequent fragmentation. Successive divisions brought about a gradual decrease in fragment size until the small coccoid cells typical of the stationary phase cells are formed. The results suggest that the cystites are really morphologically aberrant forms which are produced at the time of nutritional stress. No evidence was found to support the theories that cystites are specialized spore forms.