Memoirs: The Golgi Apparatus and Pyrenoids of Chilomonas paramecium, with remarks on the Identification of Copromonas subtilis

1940 ◽  
Vol s2-81 (324) ◽  
pp. 595-617
Author(s):  
J. BRONTÉ GATENBY ◽  
J. D. SMYTH
Keyword(s):  
Golgi Apparatus ◽  
Osmium Tetroxide ◽  
Daughter Cell ◽  
Neutral Red ◽  
The Other ◽  
Contractile Vacuole ◽  
Daughter Cells ◽  
Osmium Tetroxide Solution ◽  
Cortical Substance ◽  
Two Bodies

1. In Chilomonas paramecium the contractile vacuole is surrounded by a cortical substance (Golgi apparatus) which has the power of reducing osmium tetroxide solution and thus impregnating black (Nassonow). 2. This cortex blackens thus in over 99 per cent, of individuals in a culture which has not been dividing. In a culture in which the individuals have been rapidly dividing, the percentage of unimpregnated contractile vacnoles increases considerably, up to about 5 per cent. 3. During division of Chilomonas in about 70 per cent. of cases the osmiophile substance is very equally divided between the daughter cells. The dividing cortex comes away from the contractile vacuole, which eventually collapses, new contractile vacuoles arising in the site of the divided osmiophile material. In about 25 per cent, of division stages osmication of the cortex fails to a greater or lesser degree. There is always a very distinct tendency for this failure to take place even in the best of preparations. 4. In some cases (about 3 per cent.), during division, the entire contractile vacuole and its cortex goes over whole to one individual. A new vaeuole, apparently without cortex, arises spontaneously in the other individual. It is unlikely that all of these cases are due to failure of impregnation in one of the individuals, though this possibility cannot be roled out completely. 5. The behaviour of the original contractile vacuole cavity before separation of the daughter cells is as follows. The lipoid, having partially retreated from the vacuole, becomes separated into two parts, and the centrally placed vacuole disappears (figs. 4 and 6, Pl. 36; figs. 10 and 15, Pl. 37). New vacuoles appear in the site of the lipoid bodies in each daughter cell (fig. 5, Pl. 36). 6. Two ellipsoidal accessory bodies or pyrenoids lie on a level with the vestibule. In older cultures the two bodies are often exactly the same size and colour (corrosive osmic followed by neutral red or haematoxylin), but in rapidly dividing cultures, one body may be of normal size, whereas the other may be absent or much smaller. During cell division, one body is carried across to each daughter. No exception to this was ever found. 7. Identification of the smaller Peranemidae is in a confused state. Probably several species, and possibly even genera, have been described by various authors as Scytomonas (Copromonas) subtilis.

Memoirs: The Golgi Apparatus of Copromonas Subtilis, and Euglena sp

1938 ◽  
Vol s2-80 (320) ◽  
pp. 567-591
Author(s):  
J. BRONTË GATENBY ◽  
B. N. SINGH
Keyword(s):  
Cell Wall ◽  
Golgi Apparatus ◽  
Neutral Red ◽  
The Other ◽  
Contractile Vacuole ◽  
Daughter Cells ◽  
The Past ◽  
Early Stages ◽  
Contractile Vacuoles ◽  
Osmoregulatory Mechanism

1. In Copromonas subtilis , Dobell, and Euglena sp. there is a Golgi apparatus consisting of osmiophil material in the form of granules, which are associated with the osmoregulatory mechanism of the cell. 2. Inside the granules, water collects, so that they become spherical vacuoles, identical with what have in the past been called contractile vacuoles (Copromonas) or accessory contractile vacuoles (Euglena viridis). 3. In Euglena viridis, the Golgi apparatus is closely applied to the so-called contractile vacuole, and consists of numerous loaf-shaped osmiophil bodies which undergo a regular series of changes from systole to diastole, and vice versa. 4. In Copromonas, the osmiophil material may form a thick cortex surrounding what has been called the reservoir, it may be attached to the reservoir in fairly regular loafshaped bodies as in Euglena, or it may be completely detached from the reservoir. 5. The so-called contractile vacuoles of Copromonas are vesicles containing water, which are formed on the site of the osmiophil granules. 6. As far as we are able to say at present, the reservoir of Copromonas is indistinguishable from an enlarged contractile vacuole, and new reservoirs probably arise from swollen contractile vacuoles. It is difficult to believe that the reservoir divides into two, as has been claimed by Dobell. 7. During division of Copromonas, two reservoirs can nearly always be found in the early stages before the nucleus becomes dumb-bell shaped. These seem to have originated from the osmiophil vacuoles. 8. The remaining osmiophil material, when present, moves slightly down the cell, occupying a place in the mid-line. When the new cell-wall between the two organisms has passed down, about one-third the length of the dividing monad, the osmiophil material splits into two sub-equal groups and is so divided between the two organisms. There is therefore a definite dictyokinesis to be found in Copromonas. 9. Just at or after this period, the osmiophil material may become scattered about the upper middle and upper region of the dividing monads, but finally becomes situated in the region of the reservoir. 10. The osmiophil material (Golgi apparatus) persists throughout conjugation and encystment, even when a reservoir cannot be found. 11. There is a rhizoplast joining the basal granule of the flagellum with the intra-nuclear nucleolo-centrosome, and an axostyle is present, passing from the basal granule to the posterior end of the organism. 12. During cell division, the basal granule divides into two and appears to lose its connexion with the two nucleolo-centrosomes of the dividing nucleus. The axostyle appears to be absorbed in the early stages of division and cannot be stained at this epoch, but reappears in each moiety of the dividing organism, when the nucleus is dumb-bell shaped. It appears to reform when the two basal granules have taken their definitive position at the anterior end of the cells. 13. We agree with Wenyon that one flagellum passes over intact to one of the daughter cells at division, the other flagellum arises from the other basal granule. 14. Numerous fat granules are found throughout the organism; what have been called volutin granules in other Protozoa are present in Copromonas, and stain in neutral red. 15. Mitochondria are present mainly in the posterior region of the organism.

Memoirs: The Effect of Ultra-Centrifuging Vertebrate Neurones

1936 ◽  
Vol s2-79 (313) ◽  
pp. 73-90
Author(s):  
R. H. J. Brown
Keyword(s):  
Golgi Apparatus ◽  
Living Cell ◽  
Neutral Red ◽  
The Other ◽  
Cytoplasmic Inclusions ◽  
Fixed Material ◽  
Diffuse Form ◽  
Similar Density ◽  
Nissl Substance

1. The Golgi apparatus may appear as a network or incomplete reticulum; it is lighter than the other cytoplasmic inclusions but its form makes its displacement difficult. Its parts never approach the periphery of the cell. The neutral-red bodies have no part in its composition. 2. There exists a separate canalicular system which is connected with the surface of the cell, and otherwise is of similar dimensions to the Golgi apparatus. It is thought to represent the trophospongium of Holmgren. It is unaffected by the centrifuge. 3. The vacuome appears in the form of isolated granules which can be osmicated after staining in neutral red. They are lighter than the cytoplasm and are separate from the Golgi apparatus, though on account of their similar density they are thought to have some spatial connexion with it. 4. The mitochondria are in the form of rods and granules which are very slightly denser than the cytoplasm, and show no evidence of having any connexion with the Golgi apparatus. 5. The Nissl substance occurs as large irregular bodies in the fixed material. It is thought to be in a diffuse form in the living cell. It is much denser than the cytoplasm.

Ultrastructure of mitosis in the chloromonadophycean alga Vacuolaria virescens

1978 ◽  
Vol 31 (1) ◽  
pp. 37-51
Author(s):  
P. Heywood
Keyword(s):  
Golgi Apparatus ◽  
Nuclear Envelope ◽  
Genetic Material ◽  
Membrane Vesicles ◽  
Contractile Vacuole ◽  
Basal Bodies ◽  
Anterior Surface ◽  
Daughter Cells ◽  
Interphase Cells ◽  
Unusual Type

During preprophase in the chloromonadophycean alga Vacuolaria virescens microtubules are present around the flagellar basal bodies and extend over the anterior surface of the nucleus. These microtubules assist in the separation of the flagella and later enter the nucleus through polar gaps. During prophase the nucleoli begin to disperse and the chromosomes become condensed. At metaphase the nucleus assumes an elliptical shape and an equatorial plate of chromosomes becomes aligned across the long axis of the nucleus; kinetochores are recognizable on some of the chromosomes. The nuclear envelope remains intact over most of the surface and in places it forms folds. During anaphase chromosomes are less distinct and vesicles are present in the elongating nucleus. Most of the new nuclear envelope around the progeny nuclei is formed by coalescence of these membrane vesicles during late anaphase and telophase, although some of the original nuclear envelope may also become incorporated. During telophase disintegration of the original nuclear envelope becomes pronounced and portions of this structure are recognizable in the cytoplasm after completion of mitosis. It is suggested that this unusual type of nuclear envelope behaviour may be important in ensuring the segregation of the Golgi apparatus and contractile vacuole to progeny cells. Interphase cells contain a single extensive Golgi apparatus which is located between the anterior surface of the nucleus and the contractile vacuole. The Golgi apparatus and contractile vacuole act as an osmoregulatory system and their presence is presumably essential to the existence of the organism. Formation of a new contractile vacuole and division of the Golgi apparatus occur early in mitosis and thereafter a Golgi apparatus and contractile vacuole become associated with each of the poles of the nucleus. They retain this location throughout mitosis and during cytokinesis, with the result that an osmoregulatory system is present in each of the daughter cells. In a similar manner, microbody-like organelles are associated with the nuclear envelope during mitosis but not at interphase. Growth of the nuclear envelope during mitosis may serve as the means of partitioning these organelles to the progeny cells. Thus mitosis in Vacuolaria virescens is responsible not only for the equal segregation of the genetic material but also for the correct distribution of some of the cytoplasmic components.

scholarly journals Asymmetry of nanoparticle inheritance upon cell division: Effect on the coefficient of variation

PLoS ONE ◽  
2020 ◽  
Vol 15 (11) ◽  
pp. e0242547
Author(s):  
Tim Lijster ◽  
Christoffer Åberg
Keyword(s):  
Experimental Data ◽  
Cell Population ◽  
High Throughput ◽  
Coefficient Of Variation ◽  
Daughter Cell ◽  
The Other ◽  
Experimental Assessment ◽  
Daughter Cells ◽  
A Cell ◽  
Characteristic Evolution

Several previous studies have shown that when a cell that has taken up nanoparticles divides, the nanoparticles are inherited by the two daughter cells in an asymmetrical fashion, with one daughter cell receiving more nanoparticles than the other. This interesting observation is typically demonstrated either indirectly using mathematical modelling of high-throughput experimental data or more directly by imaging individual cells as they divide. Here we suggest that measurements of the coefficient of variation (standard deviation over mean) of the number of nanoparticles per cell over the cell population is another means of assessing the degree of asymmetry. Using simulations of an evolving cell population, we show that the coefficient of variation is sensitive to the degree of asymmetry and note its characteristic evolution in time. As the coefficient of variation is readily measurable using high-throughput techniques, this should allow a more rapid experimental assessment of the degree of asymmetry.

scholarly journals STUDIES ON THE GOLGI APPARATUS BY ELECTRON MICROSCOPY WITH PARTICULAR REFERENCE TO AOYAMA'S TECHNIQUE

1956 ◽  
Vol 2 (4) ◽  
pp. 395-402 ◽  
Author(s):  
Dennis Lacy ◽  
Cyril E. Challice
Keyword(s):  
Electron Microscopy ◽  
Golgi Apparatus ◽  
Osmium Tetroxide ◽  
Silver Impregnation ◽  
Impregnation Method ◽  
Exocrine Cells ◽  
Golgi Membranes ◽  
Osmium Tetroxide Solution

1. Aoyama's silver impregnation method for the Golgi apparatus has been used on exocrine cells of the pancreas of the mouse and studied by electron microscopy in order to determine as precisely as possible where the silver is deposited. Similar cells have also been fixed in buffered osmium tetroxide solution and compared with cells treated by the silver technique. 2. Examination of the Aoyama preparations usually revealed a light deposition of silver in the cytoplasm (hyaloplasm or matrix) and a heavy deposition of silver around a series of closely apposed vacuoles. The heavy deposition of silver was regarded as revealing the chromophilic region of the Golgi apparatus while the vacuoles were identified as the chromophobic component. 3. Comparison of the silver preparations with those fixed in buffered osmium tetroxide solution showed that the silver was primarily deposited in the region of the Golgi membranes.

Memoirs: The Cytology of Amoeba Proteus ‘Y’ and the Effects of Large and Small Centrifugal Forces

1938 ◽  
Vol s2-80 (320) ◽  
pp. 601-634
Author(s):  
B. N. SINGH
Keyword(s):  
Golgi Apparatus ◽  
Nile Blue ◽  
Cyst Formation ◽  
Neutral Red ◽  
Amoeba Proteus ◽  
Contractile Vacuole ◽  
Osmic Acid ◽  
Culture Solution ◽  
Food Material ◽  
Sudan Iv

1. When Amoeba proteus is subjected to high centrifugal force most of the cytoplasmic bodies are thrown out of the cell, so this work was done with the ordinary electrical centrifuge. 2. The stratification of the various cytoplasmic components according to their specific gravity is as follows: the contractile vacuole and the fat, being the lightest, occupy the centripetal position; then there is a layer of cytoplasm followed by mitochondria, neutral-red bodies, crystals, and nutritive spheres. The nucleus occupies a position in between the crystals and the nutritive spheres (Text-fig. 2). 3. The redistribution of the various cytoplasmic components takes place within a few minutes after amoebae have been centrifuged by the electrical centrifuge. Ultra-centrifuged organisms kept in culture solution remain rounded for 10-15 days, and no cyst formation takes place. The crystals and nutritive spheres are reformed; the former seem to be the products of excretion formed by the metabolic activity of the cell. 4. The nutritive spheres contain glycogen as reserve food material, and give positive tests for glycogen with iodine and Best's carmine. 5. There is no evidence that the bodies which stain with neutral red are the homologue of the metazoan Golgi apparatus, although they are pre-existing bodies in Amoeba proteus . The contractile vacuole does not blacken even after prolonged osmication. No certain homologue of the Golgi apparatus was found in Amoeba proteus. 6. Fat and glycogen are two distinct types of storage material present in Amoeba proteus. The former is very well seen with osmic acid, Sudan IV, and Nile blue tests.

scholarly journals Does the Semiconservative Nature of DNA Replication Facilitate Coherent Phenotypic Diversity?

2019 ◽  
Vol 201 (12) ◽  
Author(s):  
Vic Norris
Keyword(s):  
Escherichia Coli ◽  
Cell Cycle ◽  
Daughter Cell ◽  
Phenotypic Diversity ◽  
The Other ◽  
Epigenetic Mechanism ◽  
Content Type ◽  
Daughter Cells ◽  
Dna Strand ◽  
Principal Method

ABSTRACT It has been clear for over sixty years that the principal method whereby cells replicate and segregate their DNA is semiconservative. It is much less clear why it should be like this rather than, say, conservative. Recently, evidence has accumulated that supports the hypothesis that one of the functions of the cell cycle is to generate phenotypically different daughter cells, even in nondifferentiating bacteria such as Escherichia coli. Evidence has also accumulated that the bacterial phenotype is determined by the functioning of extended assemblies of macromolecules termed hyperstructures. One class of these hyperstructures is attached dynamically to a DNA strand by the coupling of transcription and translation. Previously, we proposed in the strand segregation model that one set of hyperstructures accompanies one parental strand into one daughter cell while another set of hyperstructures accompanies the other parental strand into the other daughter cell. This epigenetic mechanism results in daughter cells having different phenotypes. Here, I propose that one of the reasons why semiconservative replication has been selected is because it allows the generation of a population containing cells with very different growth rates even in steady-state conditions.

The Cytoplasmic Inclusions of the Neurones of Crustacea

1960 ◽  
Vol s3-101 (53) ◽  
pp. 75-93
Author(s):  
S. K. MALHOTRA
Keyword(s):  
Golgi Apparatus ◽  
Silver Nitrate ◽  
Osmium Tetroxide ◽  
Histochemical Study ◽  
Neutral Red ◽  
Cytoplasmic Inclusions ◽  
Golgi Methods ◽  
Astacus Fluviatilis ◽  
Nissl Substance

Four kinds of cytoplasmic inclusions can be recognized in the neurones of Leander serratus and Astacus fluviatilis. These are (i) spherical or almost spherical bodies, which often show a differentiated cortex and medulla; (ii) mitochondria, in the form of minute granules and short rods; (iii) Nissl substance, uniformly dispersed; (iv) ‘trophospongial’ structures, which are connected with the surface of the cell, and ramify in the form of delicate filaments throughout the cytoplasm. Neutral red colours the spherical bodies in life; it does not seem to interfere with their optically visible structure. The spherical bodies often burst open into rods and crescents; these correspond to what other authors have called ‘Golgi apparatus’ or ‘dictyosomes’. The term ‘Golgi apparatus’ has also been applied by certain authors to the ‘trophospongial’ structures. Histochemical study reveals that the surfaces of the spherical bodies, which are blackened by osmium tetroxide or silver nitrate in the Golgi methods, respond to tests for phospholipid after an ‘unmasking’ fixative has been used. The evidence also suggests the presence of cerebroside (galactolipid) in these bodies.

Golgi Apparatus and Melanogenesis: Ultrastructural Study of a Human Cellular Blue Nevus (Melanocytoma)

1973 ◽  
Vol 31 ◽  
pp. 380-381
Author(s):  
S.R. Allegra
Keyword(s):  
Endoplasmic Reticulum ◽  
Golgi Apparatus ◽  
Ultrastructural Study ◽  
The Other ◽  
Blue Nevus ◽  
Normal Complement ◽  
Golgi Vesicles ◽  
Golgi System ◽  
The Subject ◽  
Cellular Blue Nevus

The respective roles of the ribo somes, endoplasmic reticulum, Golgi apparatus and perhaps nucleus in the synthesis and maturation of melanosomes is still the subject of some controversy. While the early melanosomes (premelanosomes) have been frequently demonstrated to originate as Golgi vesicles, it is undeniable that these structures can be formed in cells in which Golgi system is not found. This report was prompted by the findings in an essentially amelanotic human cellular blue nevus (melanocytoma) of two distinct lines of melanocytes one of which was devoid of any trace of Golgi apparatus while the other had normal complement of this organelle.

scholarly journals The mitotic spindle mediates inheritance of the Golgi ribbon structure

2009 ◽  
Vol 184 (3) ◽  
pp. 391-397 ◽  
Author(s):  
Jen-Hsuan Wei ◽  
Joachim Seemann
Keyword(s):  
Mitotic Spindle ◽  
Daughter Cell ◽  
Daughter Cells ◽  
Spindle Poles ◽  
Golgi Membranes ◽  
Ribbon Structure ◽  
Golgi Ribbon

The mammalian Golgi ribbon disassembles during mitosis and reforms in both daughter cells after division. Mitotic Golgi membranes concentrate around the spindle poles, suggesting that the spindle may control Golgi partitioning. To test this, cells were induced to divide asymmetrically with the entire spindle segregated into only one daughter cell. A ribbon reforms in the nucleated karyoplasts, whereas the Golgi stacks in the cytoplasts are scattered. However, the scattered Golgi stacks are polarized and transport cargo. Microinjection of Golgi extract together with tubulin or incorporation of spindle materials rescues Golgi ribbon formation. Therefore, the factors required for postmitotic Golgi ribbon assembly are transferred by the spindle, but the constituents of functional stacks are partitioned independently, suggesting that Golgi inheritance is regulated by two distinct mechanisms.

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