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KMID : 0378019580010010059
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New Medical Journal
1958 Volume.1 No. 1 p.59 ~ p.63
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Morphological Studies On The Influence of Carcinogenic Substances on Chromosome.
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Abstract
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Since 1941, the success of experimental formation of cancer with tar in rabbit´s ears by Rous, a cane tissue would be produced optionally in animal. Other hand, Omuro obtained -cancer in plants by tar application and open an epoch of the cancer development i plants.
Strong reported that the mutation of susceptibility on gastric cancer formed in reproductive cells an hand on to the posterity.
Murrey and Little claimed ;´that afactor in breast cancer would be hereditary, and Bittner discribed carcinogenic factors are transmitted. from mother through the maternal milk.
Berenblum and ibis co-workers reported that the MUSTARD SULFATE, noncarcinogenic, conformed as a strong causative substance for mutation supresser the cancer development when it was used concurrently with the carcinogenic substances.
Tatum, and Demerec had a study on mutation by applying 20methylcholanthrene to Neurospora, -and Drospohila but no relationship between the hereditary behavior of mutation and the carcinogenic power was obsesved.
Boyland proposes that, the carcinogenic substance act to nucleic acid on carcinogenic mechanism and carcinogenic action is connected with the specific changes in chromosomes.
Notwithstanding the cause on the genesis of tumours, the somatic cells which constitute the individual vary in the tumour cells, specially in the malignant tumours, the normal cells vary in automatically and unrestrictedly growing neoplasm. Therefore, many observers emphasize that the cancer is produced by the mutation in somatic cells.
Here, as it would be the very interesting: problem to study experimentally about the carcinogenic substances which occur the mutation of somatic and reproductive cells, that we decided to study on the above problem.
For convinience, we observe in three divided parts; first part, the observation of chromosomes in the selected plants which is able to adminstrate the
carcinogenic substance and present the wide physicechological variation. Second part, observation of the reaction on the administration of carcinogenic substance. Third part, -observation of its heredity.
Firstly, -in this part, we studied precisely about the morphology of chromosomes of reproductive cells of Tradescantia.
1) MATERIALS AND METHOD
Materials; A tradescantia family from the agrecultural college of Seoul National University and the Choong Rang Kyo farm of Dong Kook University.
The rea ons why we selected this plant, are it shows wide physioechological variation and we surmice the plant may be represent many variation when the administration of carcinogenic substance, and the ´ convinience to observation since its long efflorescence.
Method: Pollem mother cells of the experimental plant which preserved in unified temperature and moisture are observed at its highest mitotic period, 4 -to $ a.m. by smear method and studied the movements of chromosomes microscopically after acetocarmine or hematoxylin stain.
II) RESULTS AND . DISCUSSION
The chromosome number of the plant are 2n=12, ,but there are sometiines,triploid or tetraploid. Generally, the higher value of the poliploid ´appear the higher activity of growth and the incidence of the higher vital power. The length of nuclei of the pollem mother cells in the, Diploid were 33 to 35 micron, and 40 to 70
M81 t 7} tl-Iq-.10 l Tmicron in that of the tetraploid.
In mitotic figures of diploid, the basic number in this plant, 5 pairs of chromosome arranged in perfect order at its equator and a residual pair of chromosome which separated from the, 5 pairs act automatically,, and then, the chromosomes move to the both opposite poles before or after the 5 pairs of chromosome.
In triploid, chromosomes reveals various complexity on its movements to the poles and in tetraploid, two pairs of uniquely acting chromnsomes are separated from the ordered ten pairs of chromosome.
Above discription indicates that the chromosome number of tradescantia family are 2n=12 and the author propose the basic number of chromosome in this plant are five and the extra chromosome is infered from the other system on the developmental procedure of the plant.
The "bridge", founded in triploid, is related to the above discribed fact and is imaginable as a failed result of crossing-over of the gene and prove the possibility of wide variation.
SUMMARY
The results of hereditary observation in normal tradescantia are as follows.
a) The chromosome number of tradescantia are 2n=12, and X=5 is the-basic number of chromosome and possible the wide variation.
b) The higher value of poliploid show the higher activity of growth and stronger vital, power.
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