Polyamines and crown gall tumor growth.

The effect of the polyamine spermidine on the growth of crown gall tumors was determined using the potato disc bioassay. Addition of lmM spermidine resulted in a 30-50% increase in tumor growth. The spermidine effect was found to be biphasic, with lmM being optimal.

The crown-gall potato disk bioassay as a primary screen for compounds with antitumor activity.

A variety of samples consisting of purified compounds (of various origins) and ethanol extracts from plants were assayed for their activity on the growth and initiation of crown-gall tumors on potato disks. The results demonstrated a high correlation between the ability of these compounds to inhibit the initiation and growth of crown-gall tumors on potato disks and their corresponding activity on the mouse P388 leukemia protocol. Of the 21 compounds tested to date, there were two false-positives and one false-negative.

Crown-gall tumors possess tumor-specific antigenic sites on their cell walls.

Rabbits were injected with cell walls obtained from crown-gall tumor tissue or the corresponding cell walls from normal potato tissue. The serum obtained from rabbits 53 days after they were injected with tumor cell walls contained immunoglobins that reacted with both tumor and normal cell walls as well as with the cells from the inciting strain of Agrobacterium tumefaciens. When this serum was repeatedly absorbed against normal cell walls and the cells of the inciting strain of Agrobacterium tumefaciens, only tumor-specific immunoglobins remained.

Crown Gall Tumor Disc Bioassay: A POSSIBLE AID IN THE DETECTION OF COMPOUNDS WITH ANTITUMOR ACTIVITY.

Seventeen samples consisting of purified compounds and various ethanol extracts from plant sources were tested for activity on the initiation of crown gall tumors on potato discs. The results demonstrated definite correlation between the ability of these samples to inhibit the formation of crown gall tumors and their activity on the P388 leukemia system in mice. Samples showing only cytotoxic effects in KB cell cultures did not affect tumor initiation in our system.