124 Colchicine 



Hypertrophy of the h\phae and faihire to form conidia were 

 legidarly noted among several species of fungi, but doubling of 

 chromosomes or evidence of polyploidy was never demonstrated. 

 Possible mutagenesis^-'^ was reported for Streptomyces griseu.s. Con- 

 centrations ranging from 0.5 to 1.0 per cent introduce changes in 

 growth patterns that resemble the tumors previously reviewed. No 

 better specific information is at hand for the yeasts and fungi than 

 for bacteria. That mycelial growth may be influenced is probable, 

 but polyploidy or induction of mutations is extremelv doubtful 

 (Table 4.6) . 



Colchicine increases the frequency with which resistant sporangia 

 of AUomyces javanicus developed mixed thalli from the sporophytic 

 generation. When germinating zygotes were treated, some nuclei 

 were thought to have been converted into polyploids. The cytological 

 records of chromosomes were not available to confirm the polvploidy." 

 A series of treatments involved the use of colchicine and sodium 

 nucleate, so the specific action of colchicine may be in some way re- 

 lated to the use of the sodium nucleate. 



4.4-3: Algae. The first artificially induced polyploid among plants 

 might well be credited to Gerassimov who treated Spivogyra by tem- 

 perature shock and apparently succeeded in increasing the volume of 

 the nucleus. This was done in 1901. A confirmation made some 

 years later strongly supports the thesis that Spirogyra cells were 

 doubled. One might hope that colchicine would be useful in repeat- 

 ing this classical experiment by chemical means, or at least demon- 

 strate that the drug is not effective, llie results with algae and col- 

 chicine are not any farther along than those with the other specimens 

 of fungi. i-*o. 15S. 125, 65, 07, ISO, 9, 88 ^he treatment of Spirogyra with col- 

 chicine should be tried with a wide range of concentrations and cyto- 

 logical control. 



A polyploid strain of Oedogoniuin was said to be obtained from 

 treatment with colchicine, but no exact cytological data went with the 

 report to prove the doubling of chromosomes had taken place. ^^" 



Temporary inhibition of mitosis in cells of Micrasterias thoinasi- 

 anas was recorded in cultures. The general conclusion was reached 

 that colchicine was ineffective except for some temporary changes in 

 plastid structure.^" Unfortunately, only limited ranges of concentra- 

 tions of colchicine were employed for the Micrasterias Avork. Some 

 dosages may be more effective than others. 



Leukophytic variants were isolated from colonies of Hormidium 

 sp. treated with colchicine.12.3 Several generations of subculture 

 brought a return to the chlorophyllous type. If a change was in- 

 duced, the weakness of a non-green variant did not permit a survival 

 in competition with unchanged chlorophyllous types. 



