Genetic studies on the kanamycin-resistance-system of Mycobacteriumtuberculosis var. hominis (H37Rv) was conducted by population analysis method. It is indicated that the kanamycin-resistance-system of this organism consists of multiple factors and each factor can determine any dgree of resistance. It is suggested that such high resistance to kanamycin ranging from 200μg/ml. to 1, 000μg/ml. or more is determined by mutation of any single gene. It appears that the kanamycin-resistance-system resembles the streptomycin-resistance-system in the organism.
Protoplasts of Escherichia coli K 12 have the ability to transfer their F and colicinogenic characters to recipient cells. These transfers are effectively performed when F+ col+ is used as the donor and F- col- as the recipient. Simultaneous transfer of both characters in high freuquency is observed. F- col+ protoplasts can not transfer their col+ to either F- col- or F+ col-. The transformed cells maintain the properties of the initially non-colicinogenic and F- strain except for the newly acquired col+, F+ or F+ col+ characteristics.
The present paper is to report the results of some preliminary observations on hormone- induced polyovulation and superfecundity in mature mice, with special reference to the number and development of ovulated ova. The mice used are of D-240 strain: they are 50 days in age, weighing 17 to 20gm. The average litter size from 82 litters of this strain was found to be 6.5, with a range from 2 to 12. The mice in various stage of oestrus cycle received an intramuscular injection of 10I.U. pregnant mare's serum “Serotropin” (Teikoku Hormone M.F.G.Co.), a follicle stimulating hormone. After about 40 hours, the animals were injected again with 5I.U. human chorionic hormone. Primogonyll (Schering A.G.). After treatments the mice were mated by being placed with males at the rate of one female to three males. On the following morning, the females were inspected for presence of the copulatory plug in their vaginas, and some of them were sacrificed for examining induced ovulation. The number of eggs extruded in the oviduct was 1452 in total; they vary from 23 to 135 by individual, being 53.8 on an average (Fig. 1). The results are striking in showing a remarkable polyovulation, since the number of eggs extruded in natural ovulation was 8.2 on an average. Microscopical examinations revealed that fertilized eggs in induced ovulation were normal in process of development (Figs. 6, 7, 8, 9). The animals were killd on the twelveth and fifteenth day of pregnancy. The number of uterine implantation recognized as fetus was 147 in total; they vary from 18 to 39 by individual, being 29.4 on an average. Based on the results obtaind above, it is apparent that a considerable number of eggs artificially ovulated are capable of development in the uterus.
This paper describes the results of the cytological investigations on the effects of 2, 5-bis- ethylenimino-hydroquinone (HE) upon the tumor cells of the MTK-sarcoma II, a transplantable ascites tumor of rats. A single intraperitoneal injection at dose levels of 0.3, 0.4 and 0.6mg/kg was administered to each tumor-bearing rat on the 2nd, 3rd or 4th day after transfer of the tumor. It was found that HE showed no remarkable effect on the treated animals, since the normal peritoneal cells underwent no visible harmful effect by the drug. But, HE exerted a striking destructive influence on the tumor cells: at 8 hours after injection, tumor cells were completely damaged in most cases studied. Out of 21 tumor-bearing animals received injections of the drug, 19 showed a complete recovery from the disease, having no tumor cells in their peritoneal cavities, leaving two animals in which the chemical application seemed to be unsuccessful. Most remarkable cytological patterns of the effects of HE on tumor cells were observed as follows: The deformation and swelling of nucleoli and the reduction in stainability of the nucleus were remarkable in resting cells half an hour after application. The damage of the cytoplasm was also evident by the apperarance of vacuolization and by unusual stainability of cytoplasmic contents. Further, a considerable increase in volume of tumor cells was also remarkable in the course of cellular damage. The tumor cells increased in diameter 2 to 3 times as large as the original size. They were unable to continue division, and underwent disintegration shortly. So far as the present experiments are concerned, there has occurred no residual tumor stem-cells unaffected by the drug in the peritoneal cavities of treated animals. In mitotic cells, the drug was found to cause the disintegration of chromosomes. Induced abnormalities of chromosomes leading to their disintegration are striking stickiness, translocation, fragmentation, aggregation and scattering of chromosomes at metaphase, thickening and clumping of chromosomes at prophase, and sticky bridges at ana- and telophase. In conclusion it is evident that 2, 5-bis-ethylenimino-hydroquinone seems to exert a radiomimetic action on the tumor cells.