scholarly journals Ultrastructure of the fertilized egg envelope from Melanotaenia praecox, Melanotaeniidae, Teleostei

2021 ◽  
Vol 51 (1) ◽  
Author(s):  
Joon Hyung Sohn ◽  
Dong Heui Kim
Keyword(s):  
Outer Surface ◽  
Morphological Characteristics ◽  
Adhesive Property ◽  
High Electron ◽  
Total Thickness ◽  
Perivitelline Space ◽  
Animal Pole ◽  
Egg Envelope ◽  
Electron Microscopes ◽  
Fertilized Egg

AbstractWe examined the morphology of fertilized egg and ultrastructures of fertilized egg envelopes of dwarf rainbowfish (Melanotaenia praecox) belong to Melanotaeniidae using light and electron microscopes. The fertilized eggs were spherical with adhesive filament, transparent, demersal, and had a narrow perivitelline space and small oil droplets. The size of fertilized egg was 1.02 ± 0.18 mm (n = 30), and there were two kinds of adhesive filament on the fertilized eggs. The long and thick (diameter 12.22 ± 0.52 μm, n = 20) adhesive filaments were only at the area of animal pole, and short and thin (diameter 1.99 ± 0.23 μm, n = 20) adhesive filaments were around the long filaments. A micropyle was conical shaped with adhesive filament and located near the animal pole of egg. The outer surface of fertilized egg was rough side. Also, the total thickness of the fertilized egg envelope was about 7.46 ± 0.41 μm (n = 20), the fertilized egg envelope consisted of two layers, an inner lamellae layer and an outer layer with high electron-density. And the inner layer was 8 layers. Collectively, these morphological characteristics and adhesive property of fertilized egg with adhesive filaments, and ultrastructures of micropyle, outer surface, and section of fertilized egg envelope are showed species specificity.

Comparative ultrastructure of the fertilized egg envelope in Corydoras adolfoi and Corydoras sterbai , Callichthyidae, Teleostei

2018 ◽  
Vol 82 (1) ◽  
pp. 33-38 ◽  
Author(s):  
Eun‐Kyung Choi ◽  
Joon Hyung Sohn ◽  
Sung Sik Han ◽  
Dong Heui Kim
Keyword(s):  
Egg Envelope ◽  
Comparative Ultrastructure ◽  
Fertilized Egg

scholarly journals Morphological differences in embryos of goldfish (Carassius auratus auratus) under different incubation temperatures

2019 ◽  
Vol 63 (11-12) ◽  
pp. 597-604 ◽  
Author(s):  
Hirotaro Urushibata ◽  
Eisuke Takahashi ◽  
Yu Shimizu ◽  
Toshiya Miyazaki ◽  
Takafumi Fujimoto ◽  
...  
Keyword(s):  
Carassius Auratus ◽  
Morphological Characteristics ◽  
Temperature Tolerance ◽  
Cell Stage ◽  
Animal Pole ◽  
Goldfish Carassius Auratus ◽  
Morphological Differences ◽  
Incubation Temperatures ◽  
Single Batch

The goldfish (Carassius auratus auratus) is a useful species for embryonic micromanipulations because of its large egg size and wide temperature tolerance. Here, we describe in detail the rate of development and morphological characteristics of goldfish embryos incubated at temperatures between 10 °C and 30 °C. The cleavage speed increased rapidly as temperature increased. Synchronized cell divisions occurred at 131 min intervals at 10ºC, at 33 min intervals at 20 °C, and at 19 min intervals at 30 °C during the cleavage period. The rate of hatched abnormal embryos significantly increased at temperatures of 26 °C and above, while there was no change in the number of abnormal embryos at temperatures less than 24 °C. Moreover, the blastomeres around the center of the blastodisc rose in the direction of the animal pole at temperatures less than 14 °C. At the lower temperatures, clusters of maternally-supplied germplasm were visualized both at the ends of the first three cleavage furrows and at the border between the lower and upper tiers at the 16- to 32-cell stage, with injection of artificial mRNA and vasa in situ hybridization. This study showed that temperature affects not only developmental speed but also the shape of the blastodisc and the distribution of maternally-supplied materials in the blastodisc. By controlling the temperature, it is possible for researchers to prepare many stages of embryos and shapes of the blastodisc from a single batch of eggs.

scholarly journals Morphological and anatomical features of seeds of Turkish Romulea taxa (Iridaceae) and their taxonomic significance

2015 ◽  
Vol 74 (1) ◽  
pp. 31-41 ◽  
Author(s):  
Mehmet Cengiz Karaismailoğlu
Keyword(s):  
Morphological Characteristics ◽  
Principal Component ◽  
Seed Morphology ◽  
Taxonomic Significance ◽  
Anatomical Features ◽  
Taxonomic Importance ◽  
Anatomical Characters ◽  
Electron Microscopes ◽  
Scanning Electron Microscopes ◽  
Scanning Electron

Abstract This paper reports on the assessment of morphological (macro and micro) and anatomical characters of seeds of Romulea taxa distributed in Turkey with the use of oneway analysis of variance, cluster analysis and principal component analysis. Morphological characteristics such as size, shape, color and surface of seeds were examined with the use of light and scanning electron microscopes. Thicknesses of testa and phytomelan layer, sizes of embryo in seeds were studied anatomically. The outcomes revealed that taxa were similar in some aspects such as color and shape of seeds. However, seed size, thickness of testa and phytomelan layer, shape of the epidermal cells in testa and sizes of embryo were different among taxa, and have taxonomic value in the distinction of these taxa from each other. In addition, the seed surfaces were more or less different for the examined taxa on an interspecific level. Consequently, seed morphology and anatomy with a few exceptions demonstrated diversity and they had taxonomic importance in terms of distinguishing among species.

scholarly journals THE RELATIONS OF THE PLASMA MEMBRANE, VITELLINE MEMBRANE, AND JELLY IN THE EGG OF NEREIS LIMBATA

1949 ◽  
Vol 32 (3) ◽  
pp. 351-366 ◽  
Author(s):  
Donald P. Costello
Keyword(s):  
Plasma Membrane ◽  
Sodium Chloride ◽  
Cortical Response ◽  
Vitelline Membrane ◽  
Perivitelline Space ◽  
Fertilized Egg ◽  
Normal Fertilization

1. The problem of the relation of the plasma membrane to the extraneous coats and cortex of the Nereis egg is discussed in the light of the observations of Lillie, Chambers, and Novikoff. 2. Evidence obtained from experiments with the centrifuge, and by treating eggs with alkaline sodium chloride, indicates that the plasma membrane of the unfertilized egg is external to the jelly precursor granules of the cortex. 3. Experiments with alkaline sodium chloride indicate that the perivitelline space of the fertilized egg is extraovular after jelly extrusion is complete. 4. The cortical behavior (membrane elevation) of the Nereis egg in alkaline sodium chloride and the cortical response (jelly extrusion) following activation of the egg in normal fertilization or parthenogenesis are attributed largely to the properties of the jelly, and presumably, to its reactions with calcium and hydroxyl ions.

Ultrastructural changes during nuclear maturation in Bufo arenarum oocytes

Zygote ◽  
1999 ◽  
Vol 7 (3) ◽  
pp. 261-269 ◽  
Author(s):  
Inés Ramos ◽  
Beatriz C. Winik ◽  
Susana Cisint ◽  
Claudia Crespo ◽  
Marcela Medina ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Ultrastructural Changes ◽  
Oocyte Nucleus ◽  
Annulate Lamellae ◽  
Perivitelline Space ◽  
Cortical Granules ◽  
Animal Pole ◽  
Nuclear Maturation ◽  
Bufo Arenarum ◽  
Freely Suspended

During progesterone-induced nuclear maturation the oocytes of Bufo arenarum undergo a series of nuclear and cytoplasmic changes. The breakdown of heterocellular communications between the follicular cell projections and the oocyte microvilli, and the consequent enlargement of the perivitelline space, were observed at the animal pole. The more evident cytoplasmic feature during nuclear maturation comprised the gathering of glycogen granules in clusters, some phagocytosed by empty vesicles. With respect to the location of these vesicles, some were observed in close proximity to the oolemma and others were freely suspended in the perivitelline space, extruded from the oocyte. Other visible events were the disruption of the annulate lamellae, the formation of an elaborate cortical endoplasmic reticulum and the rearrangement of the cortical granules in a monolayer immediately beneath the oolemma together with aggregates of endoplasmic reticulum cisternae. Our results show that during nuclear maturation the nuclear oocyte changes include a flattening of the spherical oocyte nucleus, its migration towards the surface of the animal pole, the disappearance of the nucleoli and the dissolution of the nuclear envelope.

scholarly journals Ultrastructure of the Fertilized Egg Envelope from Pseudobagrus fulvidraco, Bagridae, Teleostei

2016 ◽  
Vol 46 (3) ◽  
pp. 150-154
Author(s):  
Joon Hyung Sohn ◽  
Ohyun Kwon ◽  
Dong Heui Kim
Keyword(s):  
Egg Envelope ◽  
Fertilized Egg

Comparative Investigations on Various TV Image Transmission Systems used with Electron Microscopes

1969 ◽  
Vol 27 ◽  
pp. 76-77
Author(s):  
K. -H. Herrmann ◽  
D. Krahl ◽  
A. Kuebler
Keyword(s):  
Image Transmission ◽  
Beam Current ◽  
Limited Range ◽  
List Type ◽  
High Electron ◽  
Astigmatism Correction ◽  
Fluorescent Screen ◽  
Optical Magnification ◽  
Electron Microscopes ◽  
Considerable Loss

Television systems for transmitting the final image of an electron microscope offer some advantages as compared with the usual method of observing the final image on the fluorescent screen:1.The current density in the object are a can be greatly reduced, without considerable loss in resolution.2.(Electronically, in a limited range, the contrast can be increased.)3.Easy focussing and astigmatism correction at very low beam current is possible, specially in case of high electron optical magnification without necessary dark adaption.4.Several views can observe the transmitted final image at the same time.

scholarly journals Radial Carboxyterminal Peptides of Tubulin Directly Imaged in Microtubules by Electron Microscopy Tomography Exploiting Emplitude Contrast

2021 ◽  
Author(s):  
Andrea Fera ◽  
Thomas Reese ◽  
Joshua Zimmerberg ◽  
Dan Sackett
Keyword(s):  
Electron Microscopy ◽  
Outer Surface ◽  
Electron Beam Irradiation ◽  
Signal To Noise Ratio ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
High Signal ◽  
High Electron ◽  
Microscopy Image ◽  
Multiple Samples

Abstract Tubulin carboxyterminal tails (CTT) are peptides of 10-20 amino acids, unstructured and acidic, that vary in sequence between tubulin isotypes and are exposed on the outer surface of microtubules (MTs). These peptides have, so far, eluded direct visualization. In this report, electron microscopy tomography was applied to isolated MTs stained with Uranyl and tungstate salts demonstrated to resist sustained electron beam irradiation. Such resistance of high electron doses allows each electron microscopy image to be recorded with a high signal-to-noise ratio. Corresponding tomograms reconstructed from tilt series at high magnification show exceptional resolution of details, revealing features of average dimension ~ 1 nm without the need of averaging multiple samples. The known three-dimensional structure of the MT wall is apparent. But now images also reveal small stalks on the outer surface of MTs. Inspection of virtual sections demonstrates that the stalks are up to ~2.5 nm long and ~1 nm wide (at half length), protruding every 4 ± 0.8 (22) nm along the microtubule. This spacing corresponds to one stalk per tubulin monomer. The grafting point on each monomer is not random but is positioned at one end of each monomer, identifying that end as toward the (-) end of the MT. The stalks are not observed following CTT removal with subtilisin. We conclude that these stalks are the CTT peptides of tubulin.

Morphological characteristics of the walls of thrombophlebitic saphenous vein

2013 ◽  
Vol 29 (3) ◽  
pp. 164-170 ◽  
Author(s):  
F-G Jian ◽  
H-B Chu ◽  
G-Z Liu ◽  
J-H Zhao ◽  
Y-B Xu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Light Microscopy ◽  
Varicose Veins ◽  
Morphological Changes ◽  
Thrombus Formation ◽  
Morphological Characteristics ◽  
Inflammatory Cells ◽  
High Electron ◽  
Saphenous Veins ◽  
Papillary Endothelial Hyperplasia

Introduction: To investigate the morphological changes in the walls of thrombophlebitic saphenous veins. Methods: Fifty-four specimens were made into slices for haematoxylin and eosin and Masson trichrome staining; ultrathin slices were also created. Slices were observed under light microscopy and electron microscopy. Results: Under light microscopy, the tunica intima of venous wall in the thrombophlebitic saphenous veins group was obviously thickened and incomplete; intravascular papillary endothelial hyperplasia was observed. Hyperplasia of collagenous fibres in the tunica media was observed. Elastic fibres in the tunica externa became fewer, whereas nourishing vessels were significantly increased in number. Infiltration of many inflammatory cells was observed. Under electron microscopy, Auer bodies with high electron density and round granules could be seen in endothelial cells in the thrombophlebitic saphenous veins group. Smooth muscle cells had an irregular karyotype, with blurred cristae in some mitochondria. Myofilaments basically disappeared. Conclusion: Thrombus formation might aggravate re-modelling of the walls of varicose veins.

Electron-Immuno-Cytochemistry: Peroxidase-Labeled Antibody Method

1968 ◽  
Vol 26 ◽  
pp. 8-9
Author(s):  
Paul K. Nakane
Keyword(s):  
Electron Microscopy ◽  
Electron Density ◽  
Natural Extension ◽  
Antigenic Site ◽  
High Electron ◽  
Reaction Products ◽  
Small Molecular Weight ◽  
Amplifying Effect ◽  
Electron Microscopes ◽  
Immuno Cytochemistry

The application of immunohistochemistry to electron microscopy is a natural extension of the immunofluorescent technique developed by Coons for light microscopy. The lack of electron density of fluorescein has necessitated a search for a label with high electron density suitable for ultrastructural use. The label should be attached to the antibody by stable linkages, should not exhibit specific interactions with other proteins or chemicals, should not be too large in order to avoid stereo effects that might interfere with the mobility of the labeled antibody, and must remain stable and withstand the adverse physical conditions presented with electron microscopy. In search for such a label, enzymes of small molecular weight were conjugated to antibodies employing bi-functional reagents. The enzymatically and immunologically active conjugates were reacted with tissues which were then stained histochemically for the enzymes. Horseradish peroxidase was employed since it was stainable histochemically with stable reaction products visible with light and electron microscopes. In addition its endogenous localization was limited to specific sites. This system is highly sensitive because of an amplifying effect. Enzyme is not consumed in the reaction with substrate and each molecule of enzyme-labeled antibody bound to the antigenic site deposits many molecules of reaction product.

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