120 Colchicine 



Information at hand shows that the ganiciophyte stages of green 

 plants can be doubled in manner similar to the sporophytic cells, 

 notably among the seed plants. 



4.4: Microbiological Data 



Controlled cultures using unicellular organisms are admirably 

 suited for experiments \\iih colchicine. A wide concentration range 

 may be used because the strongest dosages show a minimum toxicity. 

 Furthermore, the experimental subjects are numerous considering 

 the bacteria, yeasts, filamentous fungi, algae, and protozoa. Consid- 

 erable preliminary work has been started, but contradictory conclusions 

 and no small amount of confusion still exist. 



In some cases the methods are not clearly described, nor are they 

 carefully j^lanned. Modifications such as concentration, media, and 

 exposure ^voidd prove helpful. The interpretations have been very 

 narrow, and patterned generally after the known action of colchicine 

 upon the nucleus of vascular plants and multicellular organisms. As 

 an illustration, the doubling of chromosomes is a remarkable action 

 with vascular plants, and it would be helpful to know more about 

 the hereditary materials in bacteria, but colchicine can hardly resolve 

 the problem of chromosomes in bacteria when cytologists have had 

 such great difficulties in demonstrating structures in untreated cul- 

 tures. 



Yeast cells that ha\e an advantage over bacteria in size of internal 

 structures have been tested with colchicine. The results can not be 

 considered decisive. Even among the algae where chromosome num- 

 bers for species have been established, there are no clear cytological 

 data to pro\c that the number of chromosomes can be doubled by 

 colchicine. There is discussion of haj^loids, dij)loids, and tetraploids 

 among fiuigi, but present work with colchicine does not provide 

 answers either through demonstration of chromosomes or by genetic 

 evidence. 



Changes in the sizes of cells within a culture and direct action 

 upon the growing organism indicate that the drug has some influence 

 upon growth processes related to increase in size. Of course, these 

 changes are not transmitted to succeeding generations. The mechan- 

 ism of growth by cellular enlargement can not be analyzed from such 

 tests. Metabolism of bacteria in relation to colchicine represents an 

 luicxplored field. Preliminary work has been done. In 1907. in- 

 teresting work was done on temperature and toxicity using cultures 

 of Paramecinin?^ Otherwise, this field of experimentation has been 

 overlooked. 



Finally the processes of differentiation and cellular structure are 

 influenced by colchicine. Fungi and algae show evidence that during 



