Development of the chick embryo mesoblast: pronephros, lateral plate, and early vasculature

Development ◽  
1980 ◽  
Vol 55 (1) ◽  
pp. 291-306
Author(s):  
Stephen Meier
Keyword(s):  
Chick Embryo ◽  
The Body ◽  
Lateral Plate ◽  
Cardinal Vein ◽  
Transmission Electron ◽  
Junctional Complexes ◽  
Vascular Channels ◽  
Mesenchyme Cells ◽  
Epithelial Sheets ◽  
Posterior Cardinal Vein

The early development of the mesoblast in the intermediate and lateral regions of the chick embryo was examined with the scanning and transmission electron microscope. It was found that primary mesenchyme here becomes condensed into epithelial structures that emerge in a metameric pattern. Viewed in developmental sequence, the intermediate mesoblast condenses into a narrowing cord of axially oriented cells which divert medially at regular intervals into the intersegmental interfaces of somitomeres and somites. These cells give rise to the vascular channels of the posterior cardinal vein as well as to tubular elements of the pronephros. Intermediate mesenchyme cells become epithelial, forming zonular junctional complexes apically and depositing patchy basal lamina over their basal surfaces. The lateral plate mesenchyme organizes similarly into somatic and splanchnic epithelial sheets that utilize the body coelom as their lumenal surface. Cells of the lateral plate extend filopodia basally that interweave with adjacent cells, fibrillar extracellular matrix, as well as with interstitial bodies. The pattern in the lateral plate is subtly ribbed as bands of mesoblast undulate along the axis. The central region of each band is raised while there are grooves created along lines of band abutment, corresponding to intersegmental clefts in the paraxial region and reflecting an underlying metameric pattern. These grooves are usually demarked medially by the protrusion of short segments of adjacent intermediate mesoblast. Most of the remaining primary mesenchyme develops into a non-metameric vascular epithelium, which forms a prominent anastamosing plexus between splanchnic mesoderm and endoderm. It is proposed that the emergence of primary mesenchyme into patterned epithelial anlage facilitates the distribution of neural crest cells introduced subsequently.

Otoconia formation in the chick embryo

1983 ◽  
Vol 41 ◽  
pp. 572-573
Author(s):  
C.D. Fermin ◽  
M. Igarashi
Keyword(s):  
Chick Embryo ◽  
Inner Ear ◽  
Gallus Domesticus ◽  
The Body ◽  
Abnormal Behavior ◽  
Intensive Study ◽  
Basic Fuchsin ◽  
Gestational Period ◽  
Sensory Epithelia ◽  
Transmission Electron

Otoconia are microscopic geometric structures that cover the sensory epithelia of the utricle and saccule (gravitational receptors) of mammals, and the lagena macula of birds. The importance of otoconia for maintanance of the body balance is evidenced by the abnormal behavior of species with genetic defects of otolith. Although a few reports have dealt with otoconia formation, some basic questions remain unanswered. The chick embryo is desirable for studying otoconial formation because its inner ear structures are easily accessible, and its gestational period is short (21 days of incubation).The results described here are part of an intensive study intended to examine the morphogenesis of the otoconia in the chick embryo (Gallus- domesticus) inner ear. We used chick embryos from the 4th day of incubation until hatching, and examined the specimens with light (LM) and transmission electron microscopy (TEM). The embryos were decapitated, and fixed by immersion with 3% cold glutaraldehyde. The ears and their parts were dissected out under the microscope; no decalcification was used. For LM, the ears were embedded in JB-4 plastic, cut serially at 5 micra and stained with 0.2% toluidine blue and 0.1% basic fuchsin in 25% alcohol.

scholarly journals Ultrastructure of the buccal capsule in the adult female Anguillicoloides crassus (Nematoda: Anguillicolidae)

2010 ◽  
Vol 47 (3) ◽  
pp. 170-178 ◽  
Author(s):  
M. Bruňanská ◽  
H. Fagerholm ◽  
F. Moravec ◽  
Z. Vasilková
Keyword(s):  
Adult Female ◽  
Cross Sections ◽  
Body Wall ◽  
Buccal Capsule ◽  
The Body ◽  
Transmission Electron ◽  
Junctional Complexes ◽  
Marginal Cells ◽  
First Time ◽  
Anguillicoloides Crassus

Abstract The fine structure of the buccal capsule of the adult female nematode Anguillicoloides crassus (Spirurina) was studied for the first time. Results are based on serial section (longitudinal and transverse) light and transmission electron microscopy. The buccal capsule of A. crassus is a cuticular-lined structure. It can be divided into three main parts: cheilostom, gymnostom and stegostom. The cheilostom is the anterior region of the buccal capsule with the cuticular lining continuous with the body wall cuticle and underlain by epidermal syncytia. The gymnostom is a cuticular region with portions of it very electron dense and underlain by arcade syncytia. A dense circumoral cylinder together with the circumpharyngeal ring represent the prominent characters of the gymnostom. The stegostom is formed by anterior pharyngeal cuticle underlain by muscular radial cells and epithelial marginal cells. The cephalic cuticle of A. crassus makes a direct contact with the pharyngeal cuticle at the base of the circumoral cylinder, within a circumpharyngeal ring containing projections of pharyngeal muscular and marginal cells. The circumoral cylinder, circumpharyngeal ring and pharynx are connected to the body epidermis by junctional complexes. The buccal capsule includes occasionally 3 projections of the pharynx evidently observed in serial cross sections. These ultrastructural characters may provide useful data for comparative, functional as well as evolutionary studies within the Chromadorea.

Images and Applications of Ion Explosion Spike Pits

1990 ◽  
Vol 48 (1) ◽  
pp. 584-585
Author(s):  
P. Fraundorf ◽  
J. Tentschert
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Bulk Material ◽  
Coulomb Repulsion ◽  
The Body ◽  
Atomic Scale ◽  
Early Solar System ◽  
Transmission Electron ◽  
Nuclear Particle ◽  
Particle Tracks

Since the discovery of their etchability in the early 1960‘s, nuclear particle tracks in insulators have had a diverse and exciting history of application to problems ranging from the selective filtration of cancer cells from blood to the detection of 244Pu in the early solar system. Their usefulness stems from the fact that they are comprised of a very thin (e.g. 20-40Å) damage core which etches more rapidly than does the bulk material. In fact, because in many insulators tracks are subject to radiolysis damage (beam annealing) in the transmission electron microscope, the body of knowledge concerning etched tracks far outweighs that associated with latent (unetched) tracks in the transmission electron microscope.With the development of scanned probe microscopies with lateral resolutions on the near atomic scale, a closer look at the structure of unetched nuclear particle tracks, particularly at their point of interface with solid surfaces, is now warranted and we think possible. The ion explosion spike model of track formation, described loosely, suggests that a burst of ionization along the path of a charged particle in an insulator creates an electrostatically unstable array of adjacent ions which eject one another by Coulomb repulsion from substitutional into interstitial sites. Regardless of the mechanism, the ejection process which acts to displace atoms along the track core seems likely to operate at track entry and exit surfaces, with the added feature of mass loss at those surfaces as well. In other words, we predict pits whose size is comparable to the track core width.

Fin Level Defect Isolation Inside a FinFET Using Electron Beam Alteration of Current Flow

2017 ◽  
Author(s):  
H.J. Ryu ◽  
A.B. Shah ◽  
Y. Wang ◽  
W.-H. Chuang ◽  
T. Tong
Keyword(s):  
Electron Microscopy ◽  
Electron Beam ◽  
Focused Ion Beam ◽  
Current Flow ◽  
Ion Beam ◽  
The Body ◽  
Complete Understanding ◽  
Root Cause ◽  
Transmission Electron ◽  
Defect Isolation

Abstract When failure analysis is performed on a circuit composed of FinFETs, the degree of defect isolation, in some cases, requires isolation to the fin level inside the problematic FinFET for complete understanding of root cause. This work shows successful application of electron beam alteration of current flow combined with nanoprobing for precise isolation of a defect down to fin level. To understand the mechanism of the leakage, transmission electron microscopy (TEM) slice was made along the leaky drain contact (perpendicular to fin direction) by focused ion beam thinning and lift-out. TEM image shows contact and fin. Stacking fault was found in the body of the silicon fin highlighted by the technique described in this paper.

scholarly journals Reproductive biology, embryonic development and matrotrophy in the phylactolaemate bryozoan Plumatella casmiana

2021 ◽  
Author(s):  
Julian Bibermair ◽  
Andrew N. Ostrovsky ◽  
Andreas Wanninger ◽  
Thomas Schwaha
Keyword(s):  
Embryonic Development ◽  
Embryo Sac ◽  
The Body ◽  
Transcellular Transport ◽  
Cell Contacts ◽  
Transmission Electron ◽  
Distal Side ◽  
Early Embryos ◽  
Mesoderm Formation ◽  
Cytoplasmic Processes

AbstractBryozoa is a phylum of aquatic, colonial suspension-feeders within the Lophotrochozoa. In the Phylactolaemata embryonic development occurs in an internal brood sac on the body wall accompanied by extraembryonic nutrition. Owing to previous contradictive descriptions, many aspects of their sexual reproduction require restudy. Consequently, this study analyses embryogenesis of the freshwater bryozoan Plumatella casmiana by serial sections, 3D reconstruction and transmission electron microscopy. Early embryos cleave and soon develop into blastulae with a small central cavity. The mesoderm forms by delamination starting from the distal side towards the proximal end. In later embryos two polypides form on the posterior side that ultimately will be covered by a ciliated mantle in the larva. Embryos increase in size during development and form temporary cell contacts to the embryo sac. Mesodermal cells of the embryo sac show signs of transcellular transport indicating that embryos are nourished by transferring nutrients from the maternal coelom towards the brood cavity. This study clarifies several details such as mesoderm formation and the onset of bud development. Embryos are connected to their respective embryo sacs by a variety of temporary cytoplasmic processes formed by both tissues during embryogenesis, including a ‘placental’ ring zone. Although ultrastructural data of these cell contacts are not entirely conclusive about their function, we suggest that embryos absorb nutrients via the entire surface. The close opposition of embryos to the embryo sac implies placentation as matrotrophic mode in phylactolaemate bryozoans, with embryo sacs acting as placental analogues.

The ultrastructure of the epidermis of the redia and cercaria of Parorchis acanthus, Nicoll. A study by scanning and transmission electron-microscopy

Parasitology ◽  
1971 ◽  
Vol 62 (3) ◽  
pp. 479-488 ◽  
Author(s):  
Gwendolen Rees
Keyword(s):  
Electron Micrographs ◽  
Technical Assistance ◽  
Ventral Surface ◽  
The Body ◽  
Muscle Fibres ◽  
Scanning Electron Micrographs ◽  
Large Area ◽  
Transmission Electron ◽  
Parorchis Acanthus ◽  
Scanning Electron

Scanning electron-micrographs have shown the covering of microvilli on the surface of the redia of Parorchis acanthus. In the contracted state the elongated microvilli with bulbous extremities seen in the surface grooves may be the result of compression. The surface of the epidermis of the cercaria is smooth on a large area of the ventral surface and lattice-like with microvilli, laterally, anteriorly, dorsally and on the tail. The spines on the body can be withdrawn into sheaths by the contraction of muscle fibres inserted into the basement lamina below each spine.I would like to express my sincere gratitude to Dr I. ap Gwynn of this department for preparing the scanning electron-micrographs and the School of Engineering Science, University of North Wales, Bangor for the use of their stereoscan. I should also like to thank Mr M. C. Bibby for technical assistance and Professor E. G. Gray and Dr W. Sinclair for assistance with the transmission electron-micrographs.

scholarly journals Adhesion of cells to surfaces coated with polylysine. Applications to electron microscopy.

1975 ◽  
Vol 66 (1) ◽  
pp. 198-200 ◽  
Author(s):  
D Mazia ◽  
G Schatten ◽  
W Sale
Keyword(s):  
Electron Microscopy ◽  
Sea Urchin ◽  
Mammalian Cells ◽  
Experimental Treatment ◽  
The Body ◽  
Transmission Electron ◽  
Coated Plate ◽  
Living Material ◽  
Coated Surfaces ◽  
Triton X

Cells of many kinds adhere firmly to glass or plastic surfaces which have been pretreated with polylysine. The attachment takes place as soon as the cells make contact with the surfaces, and the flattening of the cells against the surfaces is quite rapid. Cells which do not normally adhere to solid surfaces, such as sea urchin eggs, attach as well as cells which normally do so, such as amebas or mammalian cells in culture. The adhesion is interpreted simply as the interaction between the polyanionic cell surfaces and the polycationic layer of adsorbed polylysine. The attachment of cells to the polylysine-treated surfaces can be exploited for a variety of experimental manipulations. In the preparation of samples for scanning or transmission electron microscopy, the living material may first be attached to a polylysine-coated plate or grid, subjected to some experimental treatment (fertilization of an egg, for example), then transferred rapidly to fixative and further passed through processing for observation; each step involves only the transfer of the plate or grid from one container to the next. The cells are not detached. The adhesion of the cell may be so firm that the body of the cell may be sheared away, leaving attached a patch of cell surface, face up, for observation of its inner aspect. For example, one may observe secretory vesicles on the inner face of the surface (3) or may study the association of filaments with the inner surface (Fig. 1). Subcellular structures may attach to the polylysine-coated surfaces. So far, we have found this to be the case for nuclei isolated from sea urchin embryos and for the microtubules of flagella, which are well displayed after the membrane has been disrupted by Triton X-100 (Fig. 2).

Mechanisms of epibolic tissue spreading analyzed in a model morphogenetic system. Roles for cell migration and tissue contractility

1992 ◽  
Vol 102 (2) ◽  
pp. 373-385 ◽  
Author(s):  
M.T. Armstrong ◽  
P.B. Armstrong
Keyword(s):  
Extracellular Matrix ◽  
Chick Embryo ◽  
Epithelial Tissue ◽  
Cortical Cells ◽  
Culture Model ◽  
Retinal Epithelium ◽  
Core Tissue ◽  
Mesenchyme Cells ◽  
Cardiac Mesenchyme ◽  
System 1

The processes responsible for epithelial spreading during wound healing and embryonic morphogenesis were investigated in an organ culture model in which an epithelial tissue (chick embryo pigmented retinal epithelium) spread over the surface of an aggregate of mesenchyme cells (chick embryo cardiac mesenchyme). The heart mesenchyme aggregate is differentiated into a core of stellate cells associated with a fibronectin-poor matrix surrounded by a cortical zone, 2–5 cells in thickness, of flattened cells embedded in a fibronectin-rich extracellular matrix. Envelopment of the mesenchyme aggregate is accompanied by a movement of the cells and the fibronectin-rich extracellular matrix of the cortex over the core tissue in advance of the spreading pigmented retina tissue. Three distinct processes were identified as contributing to epithelial spreading in this system: (1) active migration of the pigmented retinal epithelium; (2) active contraction of the cortical cells of the mesenchyme aggregate to tow the attached epithelial tissue over the mesenchyme aggregate; and (3) ingression of surface-located cells of the mesenchyme aggregate to decrease the exposed surface area by decreasing the number of cells at the surface.

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