Isolation of cytokinins from Corynebacterium fascians.

Abstract

Corynebacterium fascians derives its name from the characteristic symptoms of disease which infections by this organism cause in plants. '-4 These symptoms can be imitated by applications of kinetin, alone or in combinations with auxin, to seedlings,5 and the bacterium is known to produce cytokinin, as measured by release of bud inhibition or the retention of chlorophyll in excised tissues.6This report is on the isolation of cytokinins from liquid cultures of C. Purification Procedures and Results.-Preliminary tests showed that the bacterial suspensions or crude extracts were toxic to the tobacco tissue and could not be bioassayed for cytokinin activity without prior treatment. Bacterial suspensions, therefore, were filtered through Celite. The filter cake was lyophylized and extracted with about 10OX its volume of chloroform. The filtrate was passed through a Dowex-50 column (described in Fig. 1) which was thoroughly washed with water and then eluted with 5 N NH40H. Both the chloroform extract and the eluate were evaporated to dryness, and each was dissolved in a volume of water equal to one tenth the bacterial suspension. Results of one such experiment (Table 1) show a total activity of ca. 500,ug/liter KE which was about equally distributed between the cells and medium, but some toxic material was still present. Other 52

Cytokinins in Seeds of Pumpkin

“…In all the solvents, the cytokinins cochromatographed-namely zeatin, 6-(,yy-dimethylallylamino)purine (9,10), and triacanthine (also a naturally occurring compound, but reported to be active only after autoclaving; References 13, 29)-migrated between RF 0.8 and 0.9. As can be seen, the RF of factor HI was quite similar to that of zeatin and triacanthine but different from 6-(y ,-y-dimethylallylamino)purine.…”

Cytokinins: Development of a Potent Antagonist

“…In particular, four compounds in the substituted-pyrazolo- [4,3- (5,6) rather than the isopentenyl (3, 4) side chain, and somewhat lower in those compounds that contained the additional methyl substituent on C-3 (4,6). The relative order of cytokinin activities was expected to be 3 > 4 > 5 > 6.…”

“…Plants presumably require cytokinins for growth, because growth of excised plant tissues is often dependent on an exogenous cytokinin supply. One cytokinin, 6-(3-methyl-2-butenylamino)purine (1) has been shown to be the active factor in the plant pathogen Corynelbacterium fascian8 (5). In addition, phytohemagglutininstimulated human lymphocyte cells are both stimulated and inhibited by 6-(3-methyl-2-butenylamino)-9-1-D-ribofuranosylpurine (2) with respect to DNA synthesis, transformation, -and mitosis (6).…”

“…Compound 2 has antitumor activity in experimental animals (7,8) and in preliminary clinical trials (9). In spite of this broad range of physiological activity and the occurrence of several different cytokinins in nature (1), including four as components of tRNA (10), as well as hundreds of synthetic cytokinins (1, 2), only one example of cytokinin antagonism has been reported in a compound that bears an obvious structural relationship to the known cytokinins (5). Although the structural relationship between this compound (6-methylaminopurine) and the -cytokinins suggests its potential utility in studies of the mechanism of cytokinin action, it would probably not be suitable, since it has a very slight activity as an antagonist.…”

“…The cytokinin activities of these compounds were determined in the tobacco bioassay (12). In order to detect anticytokinin activity, the growth of tobacco callus was observed on a standard medium to which either 6-(3-methyl-2-butenylamino)purine or 6-benzylaminopurine had been added (over a range of concentrations) and to which the other compounds (3)(4)(5)(6) were also added in different concentrations.…”