Typical pictures of the premortal enlargement of mitochondria were ob-served in liver of guinea pigs dying from experimental scurvy. Though not typical, similar pictures were also obtained in livers of mice dying from injection of Shigella dysenteriae exotoxin. Pentosenucleic aid (PNA) content of the average liver cell decreased considerably in livers of rats dying of prolonged starvation but remained unchanged in scurvy-dying guinea pig livers, the both cases showing mitochondria typically enlarged. Thus, the decrease in PNA content of the liver cell can not be one of the necessary conditions for the premortal enlargement of hepatic mitochondria. These and additional data on livers with different patterns of cytoplasmic basophilia indicate that the type of basophilia should not be taken as index of PNA content of the liver cell, though it may well be of great morphologic significance.
The application of a prefixation treatment to cells in tissue culture with a hypotonic solution facilitates crucial studies on the chromosome morphology of the Norway rat (Rattus norvegicus), especially for the location of the centromeric positions in the prometaphase and metaphase figures. Evidence is presented that of the diploid group of the rat eight autosomal pairs and the X-element consist of two-armed chromosomes.
In the present investigation, the changes in motor cells of Mimosa Pudica L. in the diurnal and nocturnal condition were studied from morphological and cytophysiological view-point. The results obtained are summarized below. 1) Tannin substances or tannin vacuoles in the plant tissue were fixed with Kaiser's solution, and a 0.5 per cent alcoholic solution of toluidin blue was discovered to be a specific agent for staining the tannin. 2) Kaiser's solution-toluidin blue method and Mallory's staining are found to tinge the motor tissue differently before and after the stimulus is received. 3) The motor tissue consists of three zones as follows: P1-zone: The most internal zone of the tissue. Cells of this have a large quantity of cytoplasm. P2-zone: Cells of this zone contain a small quantity of cytoplasm. Among the cells numerous intercellular spaces are seen. P3-zone: The concentric zone outside of P1 and P2 zones. This zone corresponds to the motor tissue in a strict meaning. The cell in this tissue has a thin cytoplasmic layer at its periphery. 4) Protoplasmic connections are observed in both P2- and P3-zones; these connections are frequently observed to traverse the central vacuoles after the stimulus is received. 5) Many air bubbles are found in the well developed intercellular spaces of P2-zone. But after the movement they can scarcely be observed. 6) The attachment point of the pulvinus to the stem was cut with scissors, just after the movement when the under side of pulvinus had strongly contracted. From the cut end of the pulvinus a juice is secreted which includes tannin and potassium salt, certain nitrates and other chemical elements. 7) In the nocturnal condition, after the stimulus is received, dilute tannin substances and other crysalloids issue from the cell. These substances are fixed by Kaiser's solution in the intercellular spaces. 8) The discharge of above indicated substances is probably due to the fact that there is an increase of permeability of the cytoplasm in the nocturnal condition as well as in the diurnal. 9) Tannin substances infiltrate the cytoplasm after the stimulus is received in the diurnal condition. And in this condition the thin cytoplasm which is pressed closely to the cell wall is frequently observed. 10) In the diurnal condition the vascular bundle after receiving the stimulus is not stained by toluidin blue any more clearly than that of the anesthetized one. 11) In the nocturnal condition, the mixing of tannin and cytoplasm is observed in some parts of the motor tissue. 12) In the main pulvinus the quantity of tannin substances tend to decrease more in the nocturnal condition than in the diurnal. 13) These phenomena exhibit the different physiological conditions in the motor tissue depending upon whether it is day or night.
For the paper chromatography of chlorophylls, the solvent toluole-alcohol (20ml: 0.1ml) was found to be effective in both flow and separation of chlorophyll-a and -b extracted from leaves with ether. Chlorophyll-a extracted from crystalline chlorophyll-lipoprotein which was differentiated by column chromatography was used as the control sample of a-component.
1. A general veew of the meiotic processes in the PMC in vivo of Fritillaria was given. They were studied in the mass of the PMC covered with the tapetum tissue, the natural condition in the anther being kept as intact as possible. 2. Some phases in the meiosis in the PMC in vivo of Lilium longifolium were described in comparison with the above. 3. Considerations about the mechanism of the chromosome movement from the prometaphase to anaphase were given as follows: a. The prometaphase begins after the third contraction of the chromosomes of the PMC. These chromosomes contract once, the surface membrane of the CPN crumples. The latter gradually absorbing water gives the opaque surface of the nucleus, which makes it difficult to observe the behaviours of the chromosomes inside the prometaphase. b. The chromosomes gradually separate from each other in the reversing CPN and makes the chromosome plate. c. With the chromosome plate as the equator the half spindles the atractoplast, are composed on both sides of the plate, the spindle pole appears on the surface of the CPN as the result of the electrostatic reduction due to the charged paired chromosomes in the CPN which is then in the dielectric condition in this phase, and this pole is the focus of the poles of each pair of the chromosomes. Consequently when the pole has just appeared, its sign of the charge is the same with that of the chromosomes, which keeps the chromosomes at the equator of the spindle, until the charge of the chromosomes reverses in the metaphase. d. After that the sign of charge of the chromosomes reverses, then there results the force of traction between the chromosomes and the pole of the spindle. 4. The chromosome movement in the anaphase is conducted by: a. the force of traction between the pole and the chromosomes, b. the mutual repulsion between the separated n-chromosomes, c. the passage in which the fibrous amphoteric molecules are arranged longitudinally in the force line due to the traction force differentiated, rejecting the short non-charged molecules in the spindle substance. The cooperation of the above three plays an important role in the chromosome movement in the anaphase, in which the early movement of chromosomes is conducted mainly by their own repulsion, the next stage chiefly by the force of attraction, the passage giving convenience to the movement of the chromosomes. 5. The I prophase and the I prometaphase are very easily influenced by intra- as well as the inter-cellular condition and also by the condition given from outside. Therfore the whole length of the time of the meiotic processes may be determined by the condition first in the prophase and next by that in the prometaphase, the anaphase movement may be the least susceptible to outward influence among them.
1. The curves representing the retardation of budding of ultraviolet in Saccharomyces are sigmoid for diploid, triploid, and tetraploid cells and exponential for haploid cells. When the curves are interpreted in terms of the multi target hypothesis, a one to one correspondence can be shown between the number of chromosome sets and the number of radio-sensitive sites per cell. 2. The rates of logarithmic inhibition of budding increase linearly with increasing polyploidy. 3. The retardation of budding by ultraviolet is photoreversible. However, photorecovery does not proceed in accordance with the dose reduction principle. After photoreactivation, cells of the entire polyploid series yield exponential inhibition of budding curves whose slopes vary independently of the number of chromosome sets per cell. 4. Survival curves for all members of the polyploid series are sigmoid. Target values show a non unitary increase with polyploidy though the rates of logarithmic inactivation are independent of the number of chromosome sets per cell. Inactivation rates are related closely, however, to the slopes of the curves for inhibition of budding which are obtained after photoreactivation. 5. Photoreactivation of inactivated cells obeys the dose reduction principle. The same proportion of damage is repaired per unit of visible light in all cells of the polyploid series. 6. The depression of budding activity by ultraviolet reflects damage scored upon both genetic and non genetic cellular components. The non genetic damage is related closely to the damage effecting cellular inactivation.
The mitotic number of several local varieties of M. indica is confirmed as 2n=28 and that of M. laevigata (2n=56) is reported as a tetraploid. No meiotic difference was observable between the several varieties of M. indica. The following points were noted:- 1) There is extreme difference in size between 12 pairs called autosomes and 2 pairs called allosomes. 2) The four large chromosomes may join variously to form a) one quadrivalent, b) one trivalent and one univalent, or c) two bivalents. 3) The quadrivalent may separate equally or unequally at anaphase. 4) The allosomes show heteropycnosity to this extent that they may be visible, adhering to the nucleolus, at early prophase, when the other chromosomes are yet unstained. 5) It is contended from present observations that a simple “XY” me-chanism cannot exist in Morus as there are four large chromosomes in the complement. 6) Out of the remaining 24 chromosomes there may occasionally be formed one trivalent and a corresponding univalent. 7) Secondary grouping in both first and second metaphase adheres usually to the number seven.