Memoirs: On the Structure of the Ovary and the Ovarian Ovum of Loris lydekkerianus, Cabr

1927 ◽  
Vol s2-71 (281) ◽  
pp. 57-74
Author(s):  
C.R. NARAYAN RAO
Keyword(s):  
Nuclear Membrane ◽  
Interstitial Cells ◽  
The Other ◽  
Follicle Cells ◽  
General Distribution ◽  
Catalytic Activities ◽  
Golgi Bodies ◽  
Intimate Relation ◽  
Nuclear Changes ◽  
Fat Bodies

There is a definite polarity in the ovarian ova as regards the distribution of the fat-bodies in the younger as well as the fully grown examples. It has not been possible to distinguish two types of ova based on the size or distribution of these deutoplasmic inclusions. The deutoplasmic pole is occupied by fat-bodies of uniformly small size, while the periphery and the plastic or nuclear pole are distinguished by the occurrence of small and large varieties of fat-spherules. Nuclear emission takes place very early in the growth of the ovum and initiates the formation of fat-bodies, and in doing so the nucleolus itself increases in size, while in the final stages of its catalytic activities it diminishes before final expulsion into the follicle cells where it is absorbed. The formation of yolk-disks is attributable to the agency of micrometachondria whose general distribution accords with the appearance of yolk and with which they are in intimate relation. Having given rise to the yolk-disks, they disappear from the fully grown ova. The Golgi bodies also initiate the formation of yolk which appears in the archoplasm, and in this process the Golgi rods are noticed to undergo appreciable diminution in size. Later in the development of the ovum the Golgi rods form a close cap on the nuclear membrane, and those which have not participated in the formation of yolk lie scattered in the general cytoplasm. Deep imaginations and their secondary ramifications occur in the ovary throughout the life of the lemur, and fresh ova arise from the germinal layers of these invaginations as well as the interstitial cells. The nuclear changes involved in the production of fresh ova are in accord with the observations already published by the other authors who have studied these changes in the rabbit, and the only point worth recording is that the diplotenic stage is less clearly marked and the dictyate stage is speeded up in the lemur.

The Structure of Sycamore Callus Cells During Division in a Partially Synchronized Suspension Culture

1970 ◽  
Vol 6 (2) ◽  
pp. 299-321
Author(s):  
K. ROBERTS ◽  
D. H. NORTHCOTE
Keyword(s):  
Cell Wall ◽  
Electron Microscope ◽  
Cell Plate ◽  
Optical Microscope ◽  
The Other ◽  
Active Movement ◽  
Developmental Sequence ◽  
Golgi Bodies ◽  
Dividing Cells ◽  
Peripheral Cytoplasm

Sycamore suspension callus cells have been partially synchronized to give a culture with a mitotic index of 15%. Living dividing cells of the culture have been examined with Nomarski differential interference optics and a comparable study made on fixed cells with the electron microscope. An organized band of reticulate cytoplasm partially encircles the nucleus at mitosis. The cell divides by the formation of a phragmosome which grows across the large vacuole; this allows the organization of the cytoplasm which forms the cell plate to be examined separately from the more general cytoplasm of the cell. The cell plate grows from one side of the cell to the other and down its length a complete developmental sequence can be seen. The Golgi bodies and the endoplasmic reticulum are probably involved in the formation of material for the construction of the cell plate and young cell wall. Microfibrils are formed within the plate in the more mature regions, while material contained within vesicles is incorporated at the young growing edge. At the edge of the plate microtubules are found and these correspond to the fibrillar appearance of the phragmoplast seen with the optical microscope. In the living cell an active movement of organelles along the peripheral cytoplasm can be seen and with fixed cells viewed with the electron microscope microtubules are often found adjacent to the plasmalemma and lying close to mitochondria, crystal-containing bodies and plastids. The appearance of crystal-containing bodies and plastids containing phytoferritin is described.

scholarly journals Effects of Imprinting and Water Activity on Transesterification and Thermostability with Lipases in Ionic Liquid

2021 ◽  
Vol 35 (1) ◽  
pp. 57-63
Author(s):  
M. Matsumoto ◽  
K. Nakao ◽  
Y. Tahara
Keyword(s):  
Ionic Liquid ◽  
Water Content ◽  
Benzyl Alcohol ◽  
Vinyl Acetate ◽  
Water Activity ◽  
Maximum Rate ◽  
The Other ◽  
Organic Media ◽  
Catalytic Activities ◽  
Michaelis Constants

The effect of bio-imprinting and water activity on catalytic activities and the thermostability of lipases was investigated for transesterification using vinyl acetate and benzyl alcohol as substrates in ionic liquid, [Cnmim][PF6] (n=4,6,8), and benzene. The catalytic activities were enhanced by imprinting in benzene and [C4mim][PF6], and the relations between the transesterification activities and the water activity in both solvents were approximately bell shaped. The reactivity of the transesterification in benzene was higher than that in [C4<br /> mim][PF6]. The effects of water activity and imprinting on the kinetic parameters in [C4mim][PF6] were examined. Without controlling the water content, the values of Km,VA and Km,BA (Michaelis constants of vinyl acetate and benzyl alcohol, respectively) decreased, and the values of Vm (maximum rate) increased by imprinting. On the other hand, by controlling the water content in the organic media, the values of Vm, Km,VA, and Km,BA increased by imprinting. The activities of lipase in ionic liquid are more strongly affected by water activity and imprinting than those in benzene. We observed effects of water activity on thermostability but none from imprinting.

Specific domains drive VM32E protein distribution and integration in Drosophila eggshell layers

2001 ◽  
Vol 114 (15) ◽  
pp. 2819-2829 ◽  
Author(s):  
Davide Andrenacci ◽  
Filippo M. Cernilogar ◽  
Carlo Taddei ◽  
Deborah Rotoli ◽  
Valeria Cavaliere ◽  
...  
Keyword(s):  
Protein A ◽  
The Other ◽  
Follicle Cells ◽  
Vitelline Membrane ◽  
Cross Linking ◽  
Protein Distribution ◽  
Membrane Domain ◽  
Membrane Component ◽  
Synthesis Stage ◽  
Transgenic Flies

A study was made of the localization and assembly of the VM32E protein, a putative vitelline membrane component of the Drosophila eggshell. The results highlight some unique features of this protein compared with the other proteins of the same gene family. At the time of its synthesis (stage 10), the VM32E protein is not detectable in polar follicle cells. However, it is able to move in the extracellular space around the oocyte and, by stage 11 is uniformly distributed in the vitelline membrane. During the terminal stages of oogenesis the VM32E protein is partially released from the vitelline membrane and becomes localized in the endochorion layer also. By analyzing transgenic flies carrying variously truncated VM32E proteins, we could identify the protein domains required for the proper assembly of the VM32E protein in the eggshell. The highly conserved vitelline membrane domain is implicated in the early interactions with other components and is required for cross-linking VM32E protein in the vitelline membrane. The terminal carboxylic domain is necessary for localization to the endochorion layer. Protein with the C-end domain deleted is localized solely to the vitelline membrane and cross-linked only in laid eggs, as occurs for the other vitelline membrane proteins.

Memoirs: A Study of the Cytoplasmic Inclusions and Nucleolar Phenomena during the Oogenesis of the Mouse

1933 ◽  
Vol s2-75 (300) ◽  
pp. 697-721
Author(s):  
R.A. R. GRESSON
Keyword(s):  
Golgi Apparatus ◽  
Close Association ◽  
Large Body ◽  
Follicle Cell ◽  
Nuclear Body ◽  
Follicle Cells ◽  
Present Contribution ◽  
Cytoplasmic Inclusions ◽  
Golgi Bodies ◽  
Nucleolar Material

1. The Golgi apparatus of the germinal epithelium consists of a dark mass of material situated at one pole of the nucleus. The mitochondria occur scattered throughout the cytoplasm. 2. The Golgi material of the very early oocyte consists of rods and granules clumped together to form a large body at one pole of the nucleus; smaller masses of Golgi material may also be present. 3. In the young oocyte, surrounded by a follicle wall, a single juxta-nuclear body is present; at a later stage the individual Golgi elements break away from the juxta-nuclear body and become distributed throughout the ooplasm. 4. In the late oocytes the Golgi elements occur in close association with the mitochondrial clumps and also scattered through the ooplasm. In tubal eggs the Golgi bodies are smaller in size and more numerous than in the ovarian ova. 5. It is concluded that the large mitochondria of Lams and Doorme correspond to the oocyte Golgi elements of the present contribution. The behaviour of the Golgi material during the growth of the ovum resembles that of the eggs of other mammals. The present findings on the structure of the juxta-nuclear Golgi material agrees with Nihoul's account for the rabbit. 6. The mitochondria of the young oocytes occur scattered through the ooplasm, but are more numerous in the vicinity of the nucleus and Golgi material. Later, the majority of the mitochondria become collected into clumps; in the tubal eggs the mitochondrial clumps are more numerous. 7. The Golgi apparatus of young follicles is situated between the follicle-cell nucleus and the pole of the cell directed towards the oocyte; in follicles consisting of several layers the position of the Golgi apparatus varies, while in fully-formed follicles the Golgi material of many of the cells surrounding the follicular cavity are directed towards the cavity. This agrees with Henneguy's findings for the Golgi apparatus of the follicle-cells of the guinea-pig. The mitochondria of the follicle-cells occur scattered through the cytoplasm but are more numerous towards the pole of the cell adjoining the oocyte. 8. The number of nucleoli present in the early oocyte varies from one to five; the majority of the older oocytes contain a single nucleolus but two may be present. Extrusion into the ooplasm of nucleolar material takes place; the nucleoli and the nucleolar extrusions are basophil (Mann's methyl-blue eosin). 9. Fatty yolk is not present in the mouse ovum. It is suggested that the Golgi elements and mitochondria play some part in yolk-formation, and that some of the granules formed by the fragmentation of the nucleolar extrusions are added to the yolkglobules already present. The yolk-globules of unsegmented tubal eggs are situated towards one pole of the cell; at the twocell stage they appear to be evenly distributed between the two cells. 10. In degenerating eggs the mitochondria are clumped; the Golgi bodies occur in small groups or are closely applied to the mitochondrial clumps. In eggs which have undergone fragmentation the Golgi bodies occur in groups, while the majority of the mitochondria are clumped. The fat-globules, previously recorded by Kingery in degenerating eggs, were identified. In material treated by Ciaccio's method for the identification of fats, appearances suggest that the Golgi elements, and possibly the mitochondria, give rise to fat. Yolk-globules could not be distinguished in the late stages of these eggs.

CATALYTIC ACTIVITY FOR METHANE OXIDATION OF GOETHITE SUPPORTED ON ALUMINA

2006 ◽  
Vol 20 (25n27) ◽  
pp. 4249-4254 ◽  
Author(s):  
KEI-ICHIRO MURAI ◽  
KOHEI TOMITA ◽  
SUGURU TOJO ◽  
TOSHIHIRO MORIGA ◽  
ICHIRO NAKABAYASHI
Keyword(s):  
Catalytic Activity ◽  
Specific Surface ◽  
Methane Oxidation ◽  
Model Experiment ◽  
The Other ◽  
Catalytic Activities ◽  
Surface Areas ◽  
Oxidation Of Methane ◽  
Other Hand ◽  
Specific Surface Areas

Two kinds of α- Fe 2 O 3 catalysts supported on χ- Al 2 O 3 and γ- Al 2 O 3 were synthesized. α- Fe 2 O 3 was prepared from α- FeOOH . As a model experiment, an investigation was made with the oxidation of methane. As all catalysts with various Fe contents supported on χ- Al 2 O 3 with various Fe contents had higher specific surface areas than those supported on γ- Al 2 O 3, α- Fe 2 O 3/χ- Al 2 O 3 catalyst has higher catalytic activities than α- Fe 2 O 3/γ- Al 2 O 3 catalyst. From SEM-EDS analyses, it is concluded that in α- Fe 2 O 3/χ- Al 2 O 3 catalyst, α- Fe 2 O 3 exists mainly on the surface of the support, because of flatness of the surface of χ- Al 2 O 3. On the other hand, in the case of α- Fe 2 O 3/γ- Al 2 O 3 catalyst, as the surface of support, γ- Al 2 O 3, is uneven, α- Fe 2 O 3 do not partially exist on the surface but in the pores.

scholarly journals Effects of glucose and insulin on the activation of lipoprotin lipase and on protein-synthesis in rat adipose tissue

1980 ◽  
Vol 188 (1) ◽  
pp. 193-199 ◽  
Author(s):  
S M Parkin ◽  
K Walker ◽  
P Ashby ◽  
D S Robinson
Keyword(s):  
Protein Synthesis ◽  
Enzyme Activity ◽  
Adipose Tissue ◽  
Lipoprotein Lipase ◽  
Specific Activity ◽  
The Other ◽  
Lipoprotein Lipase Activity ◽  
Fat Bodies ◽  
Rat Adipose Tissue ◽  
Adipose Tissue Lipoprotein Lipase

Glucose, and certain sugars that can readily be converted to glucose 6-phosphate, bring about an activation of adipose-tissue lipoprotein lipase when epididymal fat-bodies from starved rats are incubated in the presence of cycloheximide. Other substrates do not support the activation. If the tissue is preincubated in the presence of cycloheximide for longer than 2h, the ability of added glucose to activate the enzyme is lost. On the other hand, the addition of glucose still brings about an increase in lipoprotein lipase activity after preincubation in the absence of cycloheximide for as long as 4h. The magnitude of the increase in enzyme activity brought about by the addition of glucose is increased when protein synthesis is stimulated during the preincubation period by insulin. The results are interpreted in terms of the existence in adipose tissue of a proenzyme pool of lipoprotein lipase that is normally maintained by protein synthesis and that is converted to complete enzyme of higher specific activity by a process that specifically requires glucose.

scholarly journals Memoirs: The Collar-cells of Heterocœla

1895 ◽  
Vol s2-38 (149) ◽  
pp. 9-43
Author(s):  
GEORGE BIDDER
Keyword(s):  
Nuclear Membrane ◽  
The Other ◽  
Normal Life ◽  
Pathological Conditions ◽  
Other Hand ◽  
Paraffin Method ◽  
Method Show

THE collar-cells are in normal life short and barrel-shaped, with separated cylindrical collars, which are never united. In certain pathological conditions, probably connected with suffocation, they elongate very greatly, diminishing in the diameter of their upper part, or "collum;" and in some species, though not in Sycon compressum, the collars may then come into contact. In certain other pathological conditions the collar is lost, though apparently it can be regenerated. These metamorphoses appear unconnected with the ingestion of food, which also was not found to induce any migration of the collar-cells. On the other hand, migration seemed to occur under exceptionally unhealthy conditions. The collar is made up of (in Sycon compressum) about thirty parallel rods united by a film of some other substance. The flagellum is intimately connected with the nuclear membrane. There is an interstitial substance between the bodies of the cells. The area inside the collar appears to be provided with a sphincter membrane. Cells preserved and cut by the paraffin method show an average contraction of 5:4 linear in the best sections. In most preparations this contraction is uneven, producing Sollas's membrane and other fictitious appearances.

scholarly journals Memoirs: The Male Meiotic Phase in Two Genera of Marsupials (Macropus and Petauroides)

1923 ◽  
Vol s2-67 (266) ◽  
pp. 183-202
Author(s):  
W. E. AGAR
Keyword(s):  
Chromosome Number ◽  
Sex Chromosomes ◽  
Meiotic Division ◽  
Ovarian Follicle ◽  
The Other ◽  
Pachytene Stage ◽  
Follicle Cells ◽  
Crossing Over ◽  
Early Pachytene ◽  
Spermatogonial Metaphase

Macropus ualabatus has twelve chromosomes, namely 10 + XY in the male and 10 + XX in the female. In Petauroides the number is almost certainly twenty-two, the male being of the formula 20 + XY. No female counts were obtained for this animal. In the male Macropus Xis generally attached to one of the autosomes in spermatogonial mitoses. Y, which is exceedingly minute, is free. During the pachytene stage, while the autosomes are still elongated, X and Y condense into a bivalent. In the first meiotic division this bivalent is attached to an autosome. As a result of the first meiotic division the usual two classes of secondary spermatocytes are formed one with X and the other with Y. In the second meiotic division, those with X show only five separate chromosomes, showing that X, as usual, is fused with an autosome. The other class of second divisions shows five autosomes and the minute Y. In the female Macropus the sex chromosomes were never found free from the autosomes in the ovarian follicle cells, which therefore show only ten separate chromosomes. In Petauroides the sex chromosomes cannot be distinguished with certainty from the autosomes. An unequal pair of small chromosomes usually situated in the centre of the spermatogonial metaphase plates probably, however, are X and Y. Early pachytene nuclei show two compact bodies which unite into one, presumably the sex bivalent. The second reduction of the chromosome number to onequarter of the diploid total in the second meiotic division, which has been described for several species of birds and mammals, does not take place either in Macropus or Petauroides. Chromomeres are very prominent in Petauroides in the zygotene and diplotene stages. Probably in Macropus, and more convincingly in Petauroides, the cytological conditions to permit of ‘crossing over’ are present in the male. The plasmosome which appears in the pachytene stage is probably formed from the plastin or linin basis of the contracting sex chromosomes.

Freeze-Fracture Replication of Rough Endoplasmic Reticulum of Mouse Liver Cells

1972 ◽  
Vol 11 (2) ◽  
pp. 477-489
Author(s):  
A. S. BREATHNACH ◽  
C. STOLINSKI ◽  
M. GROSS
Keyword(s):  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Rough Endoplasmic Reticulum ◽  
Nuclear Membrane ◽  
Mouse Liver ◽  
Freeze Fracture ◽  
The Other ◽  
Fracture Face ◽  
Mitochondrial Membranes ◽  
En Face

Fresh, chemically unfixed, glycerinated specimens of mouse liver were examined by the technique of freeze-fracture replication without sublimation (i.e. they were not ‘etched’). Where extensive areas of fractured lamellar membranes of the rough endoplasmic reticulum are revealed en face, 2 types of fracture face are distinguishable. One of these fracture faces (A) is directed towards the cytoplasm, and the other (B) towards the cisternal cavity. A characteristic mosaic, or patchwork pattern of flat areas circumscribed by particles, is evident on both faces, and more clearly so on face B, due to a greater number of more prominent particles. Similar mosaic patterns are revealed on convex faces of the nuclear membrane, and on concave fracture faces of mitochondrial membranes, but are not evident on fracture faces of the plasma membrane. Uncertainty in establishing the exact plane of fracture of membranes in this material, since glycerol is virtually non-sublimable, makes it difficult to assess the significance of these mosaic patterns. The fact that ribosomes are not identifiable on either face of fractured endoplasmic reticulum membranes, gives no certain indication of the plane of fracture.

The Giant Mitochondria of Ctenophore Comb-Plates

1964 ◽  
Vol s3-105 (71) ◽  
pp. 301-310
Author(s):  
G. A. HORRIDGE
Keyword(s):  
Nuclear Membrane ◽  
Amorphous Material ◽  
Ciliated Cells ◽  
Giant Mitochondria ◽  
Intimate Relation ◽  
Food Particles ◽  
Mitochondrial Origin ◽  
As If

The elongated cells which bear the continually active giant cilia of the combs contain numerous large mitochondria, up to 8 µ by 6 µ in size, which are filled with irregular tubular cristae. The ciliated cells are up to 100 µ long, but only 10 µ wide, and from their centrally situated nucleus can be traced a succession of stages, tentatively interpreted as the formation, growth, erosion, and final dissolution of mitochondria. Small ones occur near the nucleus in the region of the nuclear membrane, which may there be irregular, puffy, and electron dense. Some small mitochondria are surrounded by amorphous material which stains heavily with lead; others lie against the nuclear membrane, as if in intimate relation with it. Cristae of mitochondria which are interpreted as juvenile are filled with an amorphous material; some of the cristae open to the outside of the mitochondrion. Towards the ciliated end of the cells the appearance of the mitochondria suggests that they are breaking down; this is the region where food particles are eroded and where the cilia consume energy. Here the mitochondria are shrunken and around them are numerous vesicles; their cristae are fewer and they open into the cytoplasm. Similar vesicles, which are apparently of mitochondrial origin, are extruded between the cilia from the cells. The proposed cycle of generation and disintegration of mitochondria, based upon morphology, is so far an unproved hypothesis.

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