scholarly journals PROTEIN UPTAKE IN THE OOCYTES OF THE CECROPIA MOTH

1965 ◽  
Vol 26 (1) ◽  
pp. 49-62 ◽  
Author(s):  
Barbara Stay
Keyword(s):  
Electron Microscope ◽  
Outer Surface ◽  
Dense Material ◽  
Follicle Cells ◽  
Follicular Epithelium ◽  
Vitelline Membrane ◽  
Blood Protein ◽  
Free Access ◽  
Structural Modifications ◽  
Oocyte Membrane

The formation of yolk spheres in the oocyte of the cecropia moth, Hyalophora cecropia (L.), is known immunologically to result largely from uptake of a sex-limited blood protein. Recent electron microscope analyses of insect and other animal oocytes have demonstrated fine structural configurations consistent with uptake of proteins by pinocytosis. An electron microscope analysis of the cecropia ovary confirms the presence of similar structural modifications. With the exception of two apparently amorphous layers, the basement lamella on the outer surface of the follicular epithelium and the vitelline membrane on the inner, there is free access of blood to the oocyte surface between follicle cells. Dense material is found in the interfollicular cell space and adsorbed to the outer surface of the much folded oocyte membrane. Pits in the oocyte membrane and vesicles immediately under it are lined with the same dense material not unlike the yolk spheres in appearance. Introduction of ferritin into the blood of a developing cecropia moth and its localization adsorbed to the surface of the oocyte, and within the vesicles and yolk spheres of the oocyte cortex, is experimental evidence that the structural modifications of the oocyte cortex represent stages in the pinocytosis of blood proteins which arrive at the oocyte surface largely by an intercellular route. Small tubules attached to the yolk spheres are provisionally interpreted as a manifestation of oocyte-synthesized protein being contributed to the yolk spheres.

The Fine Structure of the Membranes which Cover the Egg of the Grasshopper, Melanoplus Differentialis, with Special Reference to the Hydropyle

1963 ◽  
Vol s3-104 (67) ◽  
pp. 321-334
Author(s):  
ELEANOR H. SLIFER ◽  
SANT S. SEKHON
Keyword(s):  
Fine Structure ◽  
Electron Microscope ◽  
Special Reference ◽  
Outer Surface ◽  
Vitelline Membrane ◽  
Homogeneous Layer ◽  
Dense Layer ◽  
Melanoplus Differentialis ◽  
Pore Canals

Electron-microscope studies have shown that the epicuticle of the hydropyle consists of 2 layers. The inner is complexly folded and the outer consists of a meshwork of fine fibrils which fills the spaces between the folds. The endocuticle is laminated, penetrated by pore canals, and contains many wax-canal filaments. The filaments are especially abundant immediately before diapause. During diapause a dense, homogeneous layer is present at the outer surface of the hydropyle. It is absent before diapause and discontinuous or absent in eggs which are developing without diapause, or after diapause has been prevented or broken. The results confirm the conclusions, based on earlier studies, that the hydropyle is waterproofed by a waxy coating during diapause and that this material is absent or discontinuous in eggs which are developing. The vitelline membrane is an excessively thin, dense layer which lies below the chorion and lines the micropyles. It is less resistant at the posterior end of the egg than elsewhere. During development it is incorporated into the cuticle, which is secreted by the serosa. It is now believed that the ‘resistant endochorion’ described earlier for this species is identical with the vitelline membrane which Salt described in 1952 for the eggs of Melanoplus bivittatus.

Synthesis and Deposition of Oocyte Envelopes (Vitelline Membrane, Chorion) and the Uptake of Yolk in the Dragonfly (Odonata: Aeschnidae)

1969 ◽  
Vol 4 (1) ◽  
pp. 241-264
Author(s):  
H. W. BEAMS ◽  
R. G. KESSEL
Keyword(s):  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Electron Microscope ◽  
Follicle Cells ◽  
Vitelline Membrane ◽  
Extracellular Material ◽  
Dense Bodies ◽  
Golgi Region ◽  
Inner Surface ◽  
Oocyte Envelopes

Light and electron-microscope studies on dragonfly ovarioles reveal evidence that the precursor vitelline membrane and chorion secretions are synthesized within the follicle cells. It is suggested that the sequence of synthesis and deposition of the vitelline membrane occurs as follows. The vitelline membrane presecretion appears to be synthesized by the rough surfaced endoplasmic reticulum, giving rise to intracisternal granules. These appear to migrate in the cisternae to the region of the Golgi complex where the endoplasmic reticulum loses most of its ribosomes and the intracisternal granules move into the Golgi region where they appear within small vesicles. These seem to find their way into the Golgi cisternae where they may be incorporated with the secretions from the Golgi cisternae to produce the definitive previtelline secretion. The previtelline secretion bodies are eventually discharged into the space between the oocyte and follicle cells, forming rows of secretion bodies between the microvilli. These fuse into progressively larger bodies until a complete membrane is established. Follicle cells actively secreting precursor vitelline membrane substance show many disk-shaped, relatively clear vesicles in the cytoplasm. After the vitelline membrane is laid down, the follicle cells take on an entirely different function; namely, the synthesis and deposition of the chorion. The first visible chorion secretion appears in profile as elongate dense bodies within the Golgi cisternae which tend to coil, and in so doing, expand the cisternae. As this occurs, the enlarged cisterna, loaded with concentric coiled secretion material, separates from the remainder of the Golgi cisternae and becomes free in the cytoplasm as a prechorion secretion body. These migrate to, and collect below, the surface of the cell where they are eventually ejected between the surface folds and become incorporated into the developing chorion. Uptake of yolk in the dragonfly seems to be predominantly by micropinocytosis. The oocyte surface during active vitellogenesis bears many pits which contain an extracellular material closely applied to the outer surface of the plasma membrane. Thin, radially oriented bristles are continuous with the inner surface of the plasma membrane in this region. The pits continue to invaginate until they are cut off from the plasma membrane and come to lie in the oocyte cortex as coated vesicles. These appear to lose their coats gradually and fuse with one another to produce definitive yolk spheres.

Oogenesis in Dacus tryoni (Frogg.) (Diptera: Trypetidae)

1965 ◽  
Vol 13 (3) ◽  
pp. 423 ◽  
Author(s):  
DT Anderson ◽  
GC Lyford
Keyword(s):  
Lipid Droplets ◽  
Follicle Cells ◽  
Follicular Epithelium ◽  
Vitelline Membrane ◽  
Nurse Cells ◽  
Border Cells ◽  
Positive Material ◽  
Polytene Nuclei

Oogenesis in D. tryoni is typical of cyclorrhaphous Diptera. The ovariolar germarium produces a linear succession of 16-cell cysts enclosed by follicle cells. The cells of a cyst are interconnected by cytoplasmic canals and differentiate as 15 nurse cells and a posterior oocyte. Previtellogenesis occupies 3 days, vitellogenesis 1 day. The oocyte grows slowly during previtellogenesis, with little differentiation, rapidly during vitellogenesis, when protein and fatty yolk deposition, axial differentiation, and nuclear breakdown to first maturation metaphase, take place. The nurse cells grow rapidly during previtellogenesis and early vitellogenesis, developing large polytene nuclei and RNA-rich cytoplasm, and pour an RNA-rich nutrient stream into the oocyte during early vitellogenesis. The stream also contains P.A.S.-positive material, lipid droplets, possibly protein precursors, and nucleotides. Later, the nurse cells degenerate. Both growth and degeneration of the nurse cells are polarized, the posterior cells leading the more anterior cells. The follicular epithelium, cuboidal during previtellogenesis, differentiates as columnar around the oocyte, squamous outside the nurse cells, and anteriorly as border cells which migrate between the nurse cells to the anterior end of the oocyte. Late in vitellogenesis, the follicular epithelium secretes the chorion and vitelline membrane. It is not yet possible to discern in oogenesis the establishment in the oocyte of the prepattern essential for normal epigenesis.

scholarly journals The secretion of the eggshell of Schistocerca gregaria: ultrastructure of the follicle cells during the termination of vitellogenesis and eggshell secretion

1980 ◽  
Vol 46 (1) ◽  
pp. 455-477
Author(s):  
S.J. Kimber
Keyword(s):  
Endoplasmic Reticulum ◽  
Electron Microscope ◽  
Schistocerca Gregaria ◽  
Follicle Cells ◽  
Vitelline Membrane ◽  
Desert Locust ◽  
Golgi Bodies ◽  
Short Period ◽  
Distinct Morphology ◽  
Dense Product

The secretion of the eggshell by the follicle cells in the desert locust, Schistocerca gregaria, was studied using the electron microscope. The 3 layers of the eggshell, the vitelline membrane, the endochorion, and the exochorion, are produced in sequence over a short period of about 30–36 h. The follicle cells contain little rough endoplasmic reticulum (RER) and small inconspicuous Golgi bodies during vitellogenesis. As eggshell secretion approaches there is an increase in the amount of RER and Golgi cisternae contain electron-dense product. At each stage of the 3-phase secretion cycle the follicle cells contain Golgi bodies and secretion vesicles with distinct morphology. The follicle cells increase in breadth and decrease in height between the beginning and end of eggshell secretion. The endochorion ridges arise at the junction between follicle cells and appear to be moulded by the microvilli formed at this position. In the ovary prior to ovulation, the eggshell consists of a thin (0.5 micrometer) electron-dense vitelline and an outer fibrillar exochorion layer, 20–30 micrometer thick. Further changes take place in the vitelline membrane and the endochorion after oviposition, and a layer of curly fibres, the extrachorion, is secreted in the oviduct.

A scanning electron microscopic study on dissolving process of cholesterol gallstones by chenodeoxycholic acid (CDCA)

1978 ◽  
Vol 36 (2) ◽  
pp. 522-523
Author(s):  
T. Kanetaka ◽  
M. Cho ◽  
S. Kawamura ◽  
T. Sado ◽  
K. Hara
Keyword(s):  
Electron Microscope ◽  
Chenodeoxycholic Acid ◽  
Outer Surface ◽  
Electron Microscopic ◽  
Cholesterol Gallstones ◽  
The Core ◽  
Scanning Electron Microscopic Study ◽  
Scanning Electron Microscopic ◽  
Acceleration Voltage ◽  
Scanning Electron

The authors have investigated the dissolution process of human cholesterol gallstones using a scanning electron microscope(SEM). This study was carried out by comparing control gallstones incubated in beagle bile with gallstones obtained from patients who were treated with chenodeoxycholic acid(CDCA).The cholesterol gallstones for this study were obtained from 14 patients. Three control patients were treated without CDCA and eleven patients were treated with CDCA 300-600 mg/day for periods ranging from four to twenty five months. It was confirmed through chemical analysis that these gallstones contained more than 80% cholesterol in both the outer surface and the core.The specimen were obtained from the outer surface and the core of the gallstones. Each specimen was attached to alminum sheet and coated with carbon to 100Å thickness. The SEM observation was made by Hitachi S-550 with 20 kV acceleration voltage and with 60-20, 000X magnification.

scholarly journals AN ELECTRON MICROSCOPE STUDY OF THE DEVELOPMENT OF A MOUSE HEPATITIS VIRUS IN TISSUE CULTURE CELLS

1965 ◽  
Vol 24 (1) ◽  
pp. 57-78 ◽  
Author(s):  
J. F. David-Ferreira ◽  
R. A. Manaker
Keyword(s):  
Electron Microscope ◽  
Inclusion Bodies ◽  
Hepatitis Virus ◽  
Mouse Hepatitis Virus ◽  
Dense Material ◽  
Virus Particles ◽  
Culture Cells ◽  
Tissue Culture Cells ◽  
Tubular Body ◽  
Number Of Particles

Samples taken at different intervals of time from suspension cultures of the NCTC 1469 line of mouse liver—derived (ML) cells infected with a mouse hepatitis virus have been studied with the electron microscope. The experiments revealed that the viruses are incorporated into the cells by viropexis within 1 hour after being added to the culture. An increasing number of particles are found later inside dense cytoplasmic corpuscles similar to lysosomes. In the cytoplasm of the cells from the samples taken 7 hours after inoculation, two organized structures generally associated and never seen in the controls are observed: one consists of dense material arranged in a reticular disposition (reticular inclusion); the other is formed by small tubules organized in a complex pattern (tubular body). No evidence has been found concerning their origin. Their significance is discussed. With the progression of the infection a system of membrane-bounded tubules and cisternae is differentiated in the cytoplasm of the ML cells. In the lumen of these tubules or cisternae, which are occupied by a dense material, numerous virus particles are observed. The virus particles which originate in association with the limiting membranes of tubules and cisternae are released into their lumen by a "budding" process. The virus particles are 75 mµ in diameter and possess a nucleoid constituted of dense particles or rods limiting an electron transparent core. The virus limiting membrane is sometimes covered by an outer layer of a dense material. In the cells from the samples taken 14 to 20 hours after inoculation, larger zones of the cell cytoplasm are occupied by inclusion bodies formed by channels or cisternae with their lumens containing numerous virus particles. In the samples taken 20 hours or more after the inoculation numerous cells show evident signs of degeneration.

Two actions of juvenile hormone on the follicle cells of Rhodnius prolixus Stål

1975 ◽  
Vol 53 (8) ◽  
pp. 1187-1188 ◽  
Author(s):  
Randa Abu-Hakima ◽  
K. G. Davey
Keyword(s):  
Juvenile Hormone ◽  
Developmental Stages ◽  
Normal Animal ◽  
Rhodnius Prolixus ◽  
Follicle Cells ◽  
Follicular Epithelium ◽  
Intercellular Spaces

The follicular epithelium of vitellogenic oocytes from allatectomized females of Rhodnius fails to develop large intercellular spaces when exposed to juvenile hormone (JH) in vitro. This suggests that in the normal animal, the follicle cells require JH at two developmental stages. Differentiation of the cells in the presence of JH represents one requirement, and only those cells which have undergone this initial priming are fully competent to exhibit the second response, the development of intercellular spaces.

scholarly journals Apical, Lateral, and Basal Polarization Cues Contribute to the Development of the Follicular Epithelium during Drosophila Oogenesis

2000 ◽  
Vol 151 (4) ◽  
pp. 891-904 ◽  
Author(s):  
Guy Tanentzapf ◽  
Christian Smith ◽  
Jane McGlade ◽  
Ulrich Tepass
Keyword(s):  
Apical Membrane ◽  
Pdz Domain ◽  
Basal Membrane ◽  
Follicle Cells ◽  
Follicular Epithelium ◽  
Epithelial Surface ◽  
Mosaic Analysis ◽  
Spectrin Cytoskeleton ◽  
Surface Domains ◽  
Mesenchymal Epithelial Transition

Analysis of the mechanisms that control epithelial polarization has revealed that cues for polarization are mediated by transmembrane proteins that operate at the apical, lateral, or basal surface of epithelial cells. Whereas for any given epithelial cell type only one or two polarization systems have been identified to date, we report here that the follicular epithelium in Drosophila ovaries uses three different polarization mechanisms, each operating at one of the three main epithelial surface domains. The follicular epithelium arises through a mesenchymal–epithelial transition. Contact with the basement membrane provides an initial polarization cue that leads to the formation of a basal membrane domain. Moreover, we use mosaic analysis to show that Crumbs (Crb) is required for the formation and maintenance of the follicular epithelium. Crb localizes to the apical membrane of follicle cells that is in contact with germline cells. Contact to the germline is required for the accumulation of Crb in follicle cells. Discs Lost (Dlt), a cytoplasmic PDZ domain protein that was shown to interact with the cytoplasmic tail of Crb, overlaps precisely in its distribution with Crb, as shown by immunoelectron microscopy. Crb localization depends on Dlt, whereas Dlt uses Crb-dependent and -independent mechanisms for apical targeting. Finally, we show that the cadherin–catenin complex is not required for the formation of the follicular epithelium, but only for its maintenance. Loss of cadherin-based adherens junctions caused by armadillo (β-catenin) mutations results in a disruption of the lateral spectrin and actin cytoskeleton. Also Crb and the apical spectrin cytoskeleton are lost from armadillo mutant follicle cells. Together with previous data showing that Crb is required for the formation of a zonula adherens, these findings indicate a mutual dependency of apical and lateral polarization mechanisms.

Juvenile hormone increases ouabain-binding capacity of microsomal preparations from vitellogenic follicle cells

1983 ◽  
Vol 61 (7) ◽  
pp. 826-831 ◽  
Author(s):  
T. T. Ilenchuk ◽  
K. G. Davey
Keyword(s):  
Juvenile Hormone ◽  
Binding Capacity ◽  
Follicle Cell ◽  
Follicle Cells ◽  
Follicular Epithelium ◽  
Curvilinear Relationship ◽  
Scatchard Analysis ◽  
Ouabain Binding ◽  
Binding Characteristics ◽  
Brain Microsomes

A comparison has been made of the effects of juvenile hormone (JH) on the binding characteristics for ouabain of microsomes prepared from brain and from cells of the follicular epithelium surrounding previtellogenic or vitellogenic oocytes in Rhodnius. JH has no effect on the binding of ouabain to brain microsomes and decreases the Kd, but does not alter the Bmax for previtellogenic follicle cells. For vitellogenic follicle cells, Scatchard analysis reveals a curvilinear relationship, which is interpreted as indicating that a new population of JH-sensitive ouabain-binding sites develops as the follicle cell enters vitellogenesis. These results are related to earlier data obtained on the effect of JH on ATPase activity, volume changes in isolated follicle cells, and the development of spaces between the cells of the follicular epithelium.

Studies on the Ovarian Follicle Cells of Drosophila

1963 ◽  
Vol s3-104 (67) ◽  
pp. 297-320
Author(s):  
R. C. KING ◽  
ELIZABETH A. KOCH
Keyword(s):  
Ovarian Follicle ◽  
Protein A ◽  
Follicle Cell ◽  
Follicle Cells ◽  
Vitelline Membrane ◽  
Membrane Material ◽  
Adjacent Layer ◽  
Membrane Formation ◽  
Precursor Material ◽  
Egg Shell

Studies are described of the ultrastructure of the follicle cells which invest the oocyte of Drosophila melanogaster at the time of vitelline membrane formation. Of particular interest are organelles made up of endoplasmic reticulum organized into a husk of concentric lamellae which surround lipidal droplets. These epithelial bodies are seen only at the time the vitelline membrane is being formed, and it is assumed therefore that the lipidal material of the epithelial body may be utilized somehow in the fabrication of the vitelline membrane. Cytochemical studies have shown this membrane to contain at least 5 classes of compounds; a protein, two lipids (which may be distinguished by differences in their resistance to extraction by various solvents), and 2 polysaccharides (1 neutral and 1 acidic). Studies were made of vitelline membrane formation in the ovaries of flies homozygous for either of 2 recessive, female-sterile genes (tiny and female sterile). In the case of the ty mutation vitelline membrane material is sometimes secreted between follicle and nurse cells, while in the mutant fes vitelline membrane is observed in rare instances to be secreted between follicle cells and an adjacent layer of tumour cells. In the latter case the vitelline membrane shows altered cytochemical properties. The fact that vitelline membrane can be secreted by follicle cells not adjacent to an oocyte demonstrates that it is the follicle cell rather than the oocyte that plays the major role in the secretion of the precursor material of the vitelline membrane. Subsequently the follicle cells secrete the egg-shell, or chorion, which is subdivided into a dense, compartmented, inner endochorion, and a pale, outer exochorion. A description is given of the ultrastructure of the follicle cells during the secretion of the endochorion and the exochorion. The endochorion contains a protein, a polysaccharide, and a lipid, all of which may be distinguished cytochemically from the vitelline membrane compounds. The exochorion contains large amounts of acidic mucopolysaccharides. Specialized follicle cells form the micropylar apparatus and the chorionic appendages. The formation of the chorion and chorionic appendages is discussed in the light of information gained from abnormalities of the chorions and chorionic appendages seen in ty and fs 2.1 oocytes. Subsequent to the time the egg leaves the ovariole a layer of waterproofing wax is secreted between the vitelline membrane and the chorion.

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