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.

The secretion of the eggshell of Schistocerca gregaria, analysis of the kinetics of secretion in vitro by light and electron microscope autoradiography

1981 ◽  
Vol 50 (1) ◽  
pp. 225-243
Author(s):  
S.J. Kimber
Keyword(s):  
Electron Microscope ◽  
Schistocerca Gregaria ◽  
Similar Rate ◽  
Follicle Cells ◽  
Electron Microscope Autoradiography ◽  
Golgi Bodies ◽  
Microscope Autoradiography ◽  
Grain Distribution ◽  
Silver Grains

The secretion of the 2 main layers (endochorion and exochorion) of the eggshell of the desert locust Schistocerca gregaria was investigated using light and electron microscope autoradiography. Follicles undergoing endochorion secretion were labelled using a 3 min ‘pulse’ of [3H]leucine in vitro followed by a 0-115 min non-radioactive ‘chase’. Immediately after the pulse the silver grains were distributed over the cytoplasm and organelles including rough endoplasmic reticulum, while by 2 and 5 min Golgi bodies contained radioactivity. By 12 min from the beginning of the chase the cell apex containing small secretory vesicles was labelled. By 20 min most of the silver grains were over the endochorion. The half-transport time (t50) was 14–15 min (from mid pulse), the lag time was 9–10 min and the percentage transport rate was 14–15% per min. When a 3 min pulse of [3H]galactose was used to label exochorion precursors, the shorter t50 (11 min) and the clumped grain distribution in light microscope autoradiographs after 0-min chase suggested that galactose was incorporated in Golgi bodies. The secretion of exochorion precursors appears to occur at a similar rate to that of endochorion precursors (approximately 15% per min). The results indicate that the follicle cells are among the fastest secreting cells.

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.

Desiccation causes the proliferation of multicellular hairs, but not mucilage papillae, in Cryptothallus mirabilis (Hepatophyta): a correlated light and electron microscope study

1990 ◽  
Vol 68 (3) ◽  
pp. 697-706 ◽  
Author(s):  
Jeffrey G. Duckett ◽  
Karen S. Renzaglia ◽  
Keith Pell
Keyword(s):  
Endoplasmic Reticulum ◽  
Electron Microscope ◽  
Acid Phosphatase ◽  
Endophytic Fungus ◽  
Electron Microscope Study ◽  
Secretory Phase ◽  
Golgi Bodies ◽  
Dense Cytoplasm ◽  
Thin Walled ◽  
Multicellular Hair

When Cryptothallus dries out over periods of 4–20 days, the dorsal surfaces of the thalli become covered with multicellular hairs. The distribution of mucilage papillae and the endophytic fungus are not affected by desiccation. The hairs are thin walled and highly vacuolated whereas the mucilage papillae, like their secretory counterparts in Marchantia and mosses, are thick walled with dense cytoplasm containing stacks of endoplasmic reticulum and numerous Golgi bodies. Cytochemistry shows that the secretion is rich in carbohydrates and is derived from Golgi vesicles. After an active secretory phase, senescence of the mucilage papillae is associated with acid phosphatase activity. Key words: Aneura, Cryptothallus, desiccation, liverwort, mucilage papilla, multicellular hair, ultrastructure.

scholarly journals APPLICATIONS OF FREEZE-SUBSTITUTION TO ELECTRON MICROSCOPE STUDIES OF INVERTEBRATE OOCYTES

1961 ◽  
Vol 9 (4) ◽  
pp. 785-798 ◽  
Author(s):  
Lionel I. Rebhun
Keyword(s):  
Endoplasmic Reticulum ◽  
Electron Microscope ◽  
Freeze Substitution ◽  
Ice Crystal ◽  
Considerable Similarity ◽  
Golgi Bodies ◽  
Substitution Process ◽  
Present Technique ◽  
Lead Hydroxide ◽  
Inner Light

A modified freeze-substitution process is described which gives a low percentage (less than 5 per cent) of preparations of invertebrate eggs which appear to be ice crystal-free at the resolution of the electron microscope. The mitochondria show no membranes in these preparations but can be recognized by internal spaces with the size and the distribution of the cristae. The Golgi bodies resemble those seen with diffusion fixatives, but the limiting membranes are here double; that is, they appear to be a triple-layered sandwich with two outer dark approximately 25A layers and an inner light layer of the same thickness. The endoplasmic reticulum is clearly present and resembles that seen with diffusion fixatives. Here again, the limiting membranes are double with the same dimensions as those in the Golgi bodies. The membranes of the Golgi bodies and ER are seen after permanganate but not lead hydroxide staining. The hyaloplasm (or "cell sap") is crowded with 150 to 200A particles and these are also seen lining the ER membranes. In general, the structures as seen with the present technique show considerable similarity to those seen with diffusion fixatives.

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.

Group effects on feeding in adult males of the desert locust, Schistocerca gregaria (Forsk.), in relation to sexual maturation.

1961 ◽  
Vol 51 (4) ◽  
pp. 731-753 ◽  
Author(s):  
Maud J. Norris
Keyword(s):  
Sexual Maturation ◽  
Schistocerca Gregaria ◽  
Adult Life ◽  
Early Period ◽  
Desert Locust ◽  
Adult Males ◽  
Young Males ◽  
Full Effect ◽  
Short Period ◽  
Early Maturing

It has previously been shown that the sexual maturation of males of Scliistocerca grcgaria (Forsk.) is accelerated by crowding with other individuals of similar or greater age, and that the maturation of males kept in single pairs with older mature males is accelerated as compared with that of isolated males or males kept in single pairs with other young males or females of their own age. The effects of these groupings on the levels of feeding and excretion are investigated in the present work.Crowded males ate and excreted more than isolated ones during the first ten days of adult life. Five males in a 9-litre cage are sufficient to induce almost the full effect of crowding, and marked effects are shown when only two males are present in such a cage.After the second or third week, the level of feeding declines. This occurs earlier in early-maturing individuals, so that for a short period the crowded males eat little more or even less than the isolated ones. When the isolated males in their turn become mature their feeding again falls slightly below that of the crowded ones. When all males are isolated, there is a significant tendency for those males which eat least from the beginning of adult life and which increase their weight least to become mature earliest.The proportion of the food utilised was not affected by density. It was higher during the early period of maximum consumption than it was after the level of feeding declined.

The Effects of Calcium on the Ultrastructure of Cox's Orange Apples With Reference to Bitter Pit Disorder

1975 ◽  
Vol 23 (1) ◽  
pp. 55 ◽  
Author(s):  
HK Mahanty ◽  
BA Fineran
Keyword(s):  
Endoplasmic Reticulum ◽  
Electron Microscope ◽  
Microscope Study ◽  
Electron Microscope Study ◽  
Thin Sections ◽  
Golgi Bodies ◽  
Cool Storage ◽  
Bitter Pit ◽  
Intermediate Results

An electron microscope study on thin sections of epidermal, hypodermal and cortical tissues has been made of calcium-sprayed and unsprayed apples in relation to bitter pit disorder. Golgi bodies, endoplasmic reticulum, mitochondria, chromoplasts, vacuoles and groundplasm were better preserved in sprayed apples during cool storage for up to 2 months than in unsprayed samples. In unsprayed apples these organelles were often drastically changed. The nucleus remained reasonably well preserved in all samples. Apples from trees sprayed only once gave somewhat intermediate results.

The Respiratory Exchange of the Desert Locust (Schistocerca Gregaria) before, During and After Flight

1951 ◽  
Vol 28 (3) ◽  
pp. 344-357 ◽  
Author(s):  
AUGUST KROGH ◽  
TORKEL WEIS-FOGH
Keyword(s):  
Oxygen Consumption ◽  
Schistocerca Gregaria ◽  
Ketone Bodies ◽  
Relative Rate ◽  
Unexpected Result ◽  
Desert Locust ◽  
Average Value ◽  
Short Period ◽  
Before And After ◽  
Small Container

The respiratory exchange of mature males of the Desert Locust Schistocerca gregaria (Forskål) has been studied during tethered flight in a small container and compared with the exchange before and after flights of varying duration. All determinations were based on gas analyses, and so the CO2 output and the O2 uptake were determined simultaneously. The accuracy of the analytical procedure has been discussed and the determinations of the R.Q. before and during flight found to be valid. The figures of the oxygen consumption are reduced to N.T.P. 1. During rest at 27-30°C the oxygen consumption amounted to 0.63 l. O2/kg./hr., which means that an average male of 1.8 g. consumed 18 cu.mm. O2 per min. During flight, however, the consumption increased fifteen to fifty times, the corresponding figures being 10-30 l. O2/kg./hr. or 300-900 cu.mm. O2 per min. in an average male. 2. After even a short period (10 min.) of flight in a roundabout or in front of a wind tunnel a distinct ‘oxygen debt’ was demonstrated. After prolonged flight (90-195 min.) the ‘debt’ was nearly doubled. It corresponded to 0.3-0.7 l. O2/kg. or to the oxygen consumption during only 0.5-1.5 min. of flight, so that anaerobic processes could not amount to much. It was characteristic that the recovery lasted at least 1 hr. 3. The R.Q. in resting animals averaged 0.82, and during the first 30 min. of flight the same value was obtained, but during the following 60 min. a statistically significant decrease of the R.Q. could be demonstrated, the average value in this period being 0.75. This unexpected result strongly indicates that, unlike other insects investigated so far, locusts utilize mainly fat as a source of energy during sustained flight. 4. It is suggested that a surplus of ketone bodies caused by the intensive breakdown of fats might explain the prolonged recovery of 1-2 hr. duration in Schistocerca, the recovery after flight in Drosophila which fly on carbohydrate lasting only 2 min. or less in spite of the same relative rate of combustion.

The relationship between oöcyte and follicle in the hen's ovary as shown by electron microscopy

Development ◽  
1965 ◽  
Vol 13 (2) ◽  
pp. 215-233
Author(s):  
Ruth Bellairs
Keyword(s):  
Electron Microscopy ◽  
Cell Membrane ◽  
Raw Materials ◽  
Follicle Cell ◽  
Follicle Cells ◽  
Vitelline Membrane ◽  
Zona Radiata ◽  
Golgi Bodies ◽  
Pass Through ◽  
The Relationship

In the adult hen each oöcyte is surrounded by a capsule of follicle cells and all the raw materials that enter the oöcyte must pass through this capsule. It is not surprising, therefore, that the morphological relationships between the follicle and the oöcyte are of a highly specialized nature. Several workers have studied them, mainly by light microscopy, but their findings have not been unanimous, largely because of difficulties in resolving fine details. For instance, although it has frequently been suggested that certain structures pass from the follicle cell into the oöcyte, these structures have been interpreted by different authors as Golgi bodies, as mitochondria or as fat drops. Similarly, there have been several different theories about the relationship between the cell membrane of the oöcyte, the zona radiata and the vitelline membrane.

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