All issues
Volume 11, Issue 2
Displaying 1-7 of 7 articles from this issue
- |<
- <
- 1
- >
- >|
-
IV. Chromosomenzahlen einiger Arten and Bastarde bei OrchideenTadamasa Miduno1940 Volume 11 Issue 2 Pages 179-185
Published: December 20, 1940
Released on J-STAGE: March 19, 2009
JOURNAL FREE ACCESSDownload PDF (349K) -
VI. Studies on the Effect of the Centrifugal Force upon Nuclear DivisionK. Fujii, Tamaki Shimamura1940 Volume 11 Issue 2 Pages 186-216
Published: December 20, 1940
Released on J-STAGE: March 19, 2009
JOURNAL FREE ACCESSDownload PDF (13713K) -
I. A morphological analysis of meiosisYoshinari Kuwada1940 Volume 11 Issue 2 Pages 217-244
Published: December 20, 1940
Released on J-STAGE: March 19, 2009
JOURNAL FREE ACCESS1) The reduction division is an extreme modification of the normal mitosis, in which the chromosome division is suspended. The cases of the free nuclear division, the endomitosis and the salivary chromosome formation are regarded as other modifications in smaller degrees linking, in some loose sense, both extreme cases, the mitosis and the reduction division, in the order named.
2) In the reduction division, the regular polar chromosome, separation takes place by replacing the chromosome doubling-bydivision with that by pairing. If the chromosomes paired are sisters, the result is the somatic reduction, and if they are homologues, it is the meiotic reduction.
3) Morphologically, the meiosis is a mitosis in the prophase of which the meiotic reduction division takes place, and therefore, the first meiotic prophase is a double prophase, and the whole cycle of the meiosis is the cycle of a double mitosis in the sense that the reduction division is a modified mitosis.
4) In meiosis, physiological conditions should differ from those in the normal mitosis. These conditions may cause the chromosome pairing which gives rise to the double prophase or the prolongation of prophase that may upset the time relationship between the chro-mosome development and the spindle formation, thus resulting in the disjunction of the paired chromosomes instead of the separation of the divided chromosomes and in the occurrence of an extra polar chromosome separation which separates the latter to complete the division. The cycle of the double mitosis is thus completed, and further mitoses need not follow necessarily.
5) The theories of meiosis are reviewed and an alternative or a modification is suggested based on DARLINGTON'S principle of attraction between single chromosomes and repulsion between pairs of pairs, modifying it by adopting instead of the actual singleness an apparent singleness resulting from the lateral union of the chromatids as a response to the physiological condition in the early prophase of meiosis. The drawn out state of the leptotene or pairing threads is also considered to be responsible for the completion of pairing.View full abstractDownload PDF (1731K) -
Taku Komai, Takesi Takaku1940 Volume 11 Issue 2 Pages 245-260
Published: December 20, 1940
Released on J-STAGE: March 19, 2009
JOURNAL FREE ACCESS1. A strain of D. virilis, having two independent inversions in the X-chromosome In (X) Spd, were obtained by X-ray treatment. The extents of the inversions are illustrated in Figs. 1, 2. From this original strain two secondary strains In (X) Sp and In (X) Sd, each with one of these inversions, have been derived through the crossing over in the intercalary section.
2. All the In(X) Spd, In (X) Sd and In (X) Sp strains greatly ;suppress the crossing over in the regions included in the inversions. That of the intercalary section in In (X.) Spd is also suppressed to no smaller degree. The crossing over in the uninverted distal sections in all the three strains is suppressed very little, except possibly that in the directly adjacent regions, The crossing over in the section proximal to In (X) Sd is suppressed more markedly.
3. The heterozygous In (X) Spd strain throws 13-14 times as many primary exceptions of either sex as the normal strain, the sex-ratio among the exceptions being 1 _??_:5.4 _??_ The In (X) Sd strain throws nearly half as many primary exceptions as does the In (X) Spd strain. The In (X) Sp strain does not produce any greater number of exceptions than the normal strain.
4. The secondary non-disjunctions are 10 times as frequent in the heterozygous In (X) Spd strain as in the normal strain, the sexratio among the exceptions being 1 _??_:1.24 _??_ Some superfemales and some XO males were found among the progeny of the XXY females.
5. The reduction of crossing over by the heterozygous inversion is apparently due to various causes. The fact that the breakage points of an inversion have a common property with the centromere, in that the pairing chromosomes remain in asynapsis in their proximities, is to be counted among them.
6. The primary non-disjunction is correlated somehow with the suppression of crossing over especially in the middle region of the chromosome, where chiasmata are most concentrated.
7. The suppression of chiasmata plays a more important role for the secondary non-disjunction than for the primary non-disjunction. The comparative scarcity of secondary exceptions and the marked disparity of sexes among them in D. virilis, seem to be correlated with the more intimate regional affinity of the X-chromosomes in this species than in D. melanogaster.View full abstractDownload PDF (839K) -
Golgi apparatus of pancreatic acinar cells in the mouse in fixed and living conditionSirô Tarao1940 Volume 11 Issue 2 Pages 261-281
Published: December 20, 1940
Released on J-STAGE: March 19, 2009
JOURNAL FREE ACCESS1. The contour of the Golgi apparatus of the pancreatic acinar cells in white mouse is gradually augmented in thickness as the degree of osmium impregnation increases.
2. The Golgi apparatus of the acinar cell was disclosed by the writer's own new proteolytic enzyme-Nile blue sulphate technique. The Golgi apparatus thus prepared accords fully with that impregnated properly after Kolatschev's method. This fact means that the classical metallic impregnation methods when employed properly give an exact result at least in the fixed material.
3. By the application of the new technique it becomes evident that the zymogen granules contain more or less quantity of a certain lipoid substance.
4. Photomicrographs of the Golgi apparatus in the living acinar cells could be taken successfully on the preparations stained by the intraperitoneal injection of Nile blue sulphate. The Golgi apparatus are stained light blue assuming irregular networks, which are quite similar to those demonstrated by means of the writer's new technique and the classical osmium impregnation methods when properly applied. It is verified eventually that the Golgi apparatus really exists in the living cells with the same morphology as revealed by the classical technique.
5. In the living acinar cells the vacuomes, which stain intensely blue with Nile blue sulphate, are easily distinguishable from the genuine Golgi apparatus.
6. The cytoplasm of the acinar cells is not digestible with pepsin, while trypsin digests the cytoplasm and the protein component of the Golgi apparatus. The lipoid substance of the Golgi apparatus remaining after the trypsin digestion is insoluble in aceton and is easily dissolved in alcohol. This property of solubility means that the lipoid component of the Golgi apparatus of the acinar cells is a lecithin-like substance, which is not contained in the apparatus of hepatic cells of the same animal and the newt. This difference in chemical nature leads the writer to suppose manifold modifications in the ingredients of the apparatus as the tissue differs.
7. Judging from the nature of solubility in the organic solvents and in the enzyme, the lipoid substance located on the cell boundaries seems to be the same substance which is contained in the Golgi apparatus.View full abstractDownload PDF (8023K) -
Meiosis in diploid and tetraploid forms of Carex siderosticta HanceNobunori Tanaka1940 Volume 11 Issue 2 Pages 282-310
Published: December 20, 1940
Released on J-STAGE: March 19, 2009
JOURNAL FREE ACCESS1) The maturation divisions of diploid and tetraploid forms of Carex siderosticta Hance have been described. From the cytological and morphological points of view the tetraploid in question has been concluded to be autotetraploid.
2) Chromosome behavior in meiosis of the diploid was quite regular, while that of the tetraploid was accompanied by some irregularities as seen in the case of general autotetraploids. Meiotic irregularities seen in the tetraploid are chiefly due to irregular separation of the multivalents present at IM.
3) In the tetraploids, owing to the meiotic irregularities, about 30% of the gametes observed were unbalancing, and reduction in fertility was observed.
4) Factors which may be concerned to the reduced fertility in the autotetraploids and their significance for the aneuploidy in the genus Carex have been discussed.
Here the writer wishes to express his best thanks to Prof. Y. Sinoto, by whose suggestion these studies were started, for his valuable advice throughout the course of the work. A part of the expenses of this work was defrayed out of a grant from the Japan Society for the Promotion of Scientific Research.View full abstractDownload PDF (2550K) -
Cytoplasmic changes in SpirogyraY. Nishina, Y. Sinotô, D. Satô1940 Volume 11 Issue 2 Pages 311-318
Published: December 20, 1940
Released on J-STAGE: March 19, 2009
JOURNAL FREE ACCESSThe elasticity of cytoplasm in Spirogyra, measured by means of the centrifuge method, decreased when exposed to meutron rays (cf. table 2). Change of the elasticity induced by the neutron bombardment may be attributed chiefly to alteration in the condition of the peripheral cytoplasm especially of Rinnenplasma which con. nects chloroplasts to the cell membrane. The method of plasmolysis was also employed, but the results were inconclusive.
This work was carried out according to the program of the Atomic Nucleus Sub-committee of the Japan Society for the Promotion of Scientific Research to which we wish to express our gratitude. We are indebted to the Japan Wireless Telegraph Company for the electromagnet and other equipment used for the cyclotron, and to the Mitsui-Hoonkwai Foundation, the Tokyo Electric Light Company, and Mr. G. Hattori, President of K. Hattori Company, for financial aid. We acknowledge the kind assistances given by our colleges of the Nuclear Research Laboratory in connection with irradiation of samples.View full abstractDownload PDF (8204K)
- |<
- <
- 1
- >
- >|