Cell types of the endocrine pancreas in the shark Scyliorhinus stellaris as revealed by correlative light and electron microscopy

1981 ◽  
Vol 215 (3) ◽  
Author(s):  
K. Kobayashi ◽  
S. Syed Ali
Keyword(s):  
Electron Microscopy ◽  
Endocrine Pancreas ◽  
Light And Electron Microscopy ◽  
Cell Types

scholarly journals The Fine Structure of the Wheat Scutellum During Germination

1972 ◽  
Vol 25 (3) ◽  
pp. 469 ◽  
Author(s):  
JG Swift ◽  
TP O'brien
Keyword(s):  
Electron Microscopy ◽  
Fine Structure ◽  
Epithelial Cells ◽  
Light And Electron Microscopy ◽  
Cell Types ◽  
Wall Material ◽  
Cytological Evidence ◽  
Starch Grains ◽  
Parenchyma Cells ◽  
Cytological Changes

The cytological changes that take place in the scutellar epithelium and parenchyma during the first 5 days of germination are described by light and electron microscopy. Within 6 hr small starch grains appear in the plastids of both cell types and the size and number of starch grains increase gradually as germination proceeds. Later in germination starch disappears again from the plastids in the epithelial cells, but large starch grains still remain in the parenchyma cells. The reserves of the protein bodies are hydrolysed and the residual vacuoles undergo extensive coales-cence. Modifications in the appearance of the wall material of the epithelial cells as these cells elongate are illustrated and possible functional bases for these changes are suggested. The cells of the scutellar epithelium show no cytological evidence for their known functions of diastase secretion and nutrient absorption.

scholarly journals The Culture and Correlative Electron Microscopy of Pollen Mother Cells in Meiosis: Development of Techniques and Some Observations on Selected Topics

2021 ◽  
Author(s):  
◽  
Kenneth George Ryan
Keyword(s):  
Electron Microscopy ◽  
Light And Electron Microscopy ◽  
Cell Formation ◽  
Cell Types ◽  
Future Research ◽  
Thin Sections ◽  
Pollen Mother Cells ◽  
Spindle Elongation ◽  
Mother Cells ◽  
Metaphase I

<p>Reliable techniques for the living cell culture and correlative light and electron microscopy (EM) of meiotic pollen mother cells (PMCs) of Iris spuria, Allium triquetrum and Tradescantia flumenensis are described in detail. Living PMCs were successfully cultured in a slide chamber on agar/sucrose medium. Cells were covered with an inert oil to prevent their dehydration, and some cells were cultured from metaphase I to tetrad cell formation over a 20 hour period. Other PMCs were fixed with glutaraldehyde and flat embedded using a modification of the agar sandwich technique of Mole-Bajer and Bajer (1968). This technique was developed to permit the preselection of PMCs at known meiotic stages, for subsequent EM examination. Serial thin sections were cut at known planes of section; and 3-D reconstructions of MT distribution, and MT counts from transverse sections were completed. It was also possible to examine sections of an Iris anaphase I PMC which had been previously studied in life. Anaphase I and II chromosome velocities were analysed in the three species. Mean velocities were approximately 0.5 mu m/min with some variation from cell to cell and between sister half-spindles. In Allium anaphase I there was also variation in chromosome velocity within the half-spindle; and this variation was found not to be related to chromosome position on the metaphase I plate. Spindle elongation was zero in Allium anaphase I and in Iris anaphase II, but was detectable in Allium anaphase II (40%) and in "Iris anaphase I (l5%). The extent of spindle elongation in Tradescantia could not be determined. The kinetochore region in the first meiotic division consisted of two closely appressed, but structurally (and functionally) distinct, sister kinetochores. At meiosis II, the two sister kinetochores were separate from each other and faced opposite poles. The kinetochore arrangement probably changes from side-by-side (meiosis I) to back-to-back (meiosis II) during chromosome recondensation at prophase II in these cells. Bundles of non-kinetochore microtubules (nkMTs) span the interzone between sister chromosome units at metaphase I and II and anaphase II. Bundles of kinetochore MTs (kMTs) do not increase in divergence at any stage of meiosis studied; there was little interaction between nkMTs and kMTs, and MT-MT cross bridges were rare. These observations are not consistent with models of chromosome movement based on MT sliding or zipping. No relationship was found between nkMT distribution and spindle elongation, and the several different nkMT distributions which have been reported for other cell types may be variations on a structural theme. Spindle endoplasmic reticulum (ER) in meiosis II was found to be derived largely from invaginations and evaginations of the nuclear envelope. Growth of existing spindle ER was proposed to account for the doubling in the amount of ER observed between interphase and prometaphase II. Randomly oriented elements of ER, in early prometaphase II spindles may become passively aligned along the interpolar axis and then actively transported polewards at later stages of prometaphase II and metaphase II. Suggestions for future research are offered.</p>

scholarly journals Automatic whole cell organelle segmentation in volumetric electron microscopy

2020 ◽  
Author(s):  
Larissa Heinrich ◽  
Davis Bennett ◽  
David Ackerman ◽  
Woohyun Park ◽  
John Bogovic ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Light And Electron Microscopy ◽  
Open Data ◽  
Computer Code ◽  
Cell Types ◽  
Cell Organelle ◽  
Whole Cells ◽  
Macromolecular Assemblies

Cells contain hundreds of different organelle and macromolecular assemblies intricately organized relative to each other to meet any cellular demands. Obtaining a complete understanding of their organization is challenging and requires nanometer-level, threedimensional reconstruction of whole cells. Even then, the immense size of datasets and large number of structures to be characterized requires generalizable, automatic methods. To meet this challenge, we developed an analysis pipeline for comprehensively reconstructing and analyzing the cellular organelles in entire cells imaged by focused ion beam scanning electron microscopy (FIB-SEM) at a near-isotropic size of 4 or 8 nm per voxel. The pipeline involved deep learning architectures trained on diverse samples for automatic reconstruction of 35 different cellular organelle classes - ranging from endoplasmic reticulum to microtubules to ribosomes - from multiple cell types.Automatic reconstructions were used to directly quantify various previously inaccessible metrics about these structures, including their spatial interactions. We show that automatic organelle reconstructions can also be used to automatically register light and electron microscopy images for correlative studies. We created an open data and open source web repository, OpenOrganelle, to share the data, computer code, and trained models, enabling scientists everywhere to query and further reconstruct the datasets.

scholarly journals The larval midgut of Anticarsia gemmatalis (Hübner) (Lepidoptera: Noctuidae): light and electron microscopy studies of the epithelial cells

2004 ◽  
Vol 64 (3b) ◽  
pp. 633-638 ◽  
Author(s):  
S. M. Levy ◽  
A. M. F. Falleiros ◽  
E. A. Gregório ◽  
N. R. Arrebola ◽  
L. A. Toledo
Keyword(s):  
Electron Microscopy ◽  
Endocrine Cells ◽  
Secretory Granules ◽  
Light And Electron Microscopy ◽  
Cell Types ◽  
Anticarsia Gemmatalis ◽  
Epithelial Tissue ◽  
Basal Region ◽  
Transmission Electron ◽  
Basal Portion

The morphology of the midgut epithelium cells of Anticarsia gemmatalis (Hübner) larvae is described by light and transmission electron microscopy. The midgut of A. gemmatalis is the largest portion of the digestive tract, with three distinct regions: proximal, media and distal. Its wall is formed by pseudostratified columnar epithelial tissue having four cell types: columnar, goblet, regenerative, and endocrine cells. The columnar cells are numerous and long, with the apical portion showing many lengthy microvilli and the basal portion invaginations forming a basal labyrinth. The goblet cells have a large goblet-shaped central cavity delimited by cytoplasmic projections filled with mitochondria. The regenerative cells present electron-dense cytoplasm and few organelles. The endocrine cells are characterized by electron-dense secretory granules, usually concentrated in the cytoplasm basal region.

scholarly journals Immunocytochemical localization of peptidylglycine alpha-amidating monooxygenase enzymes (PAM) in human endocrine pancreas.

1993 ◽  
Vol 41 (3) ◽  
pp. 375-380 ◽  
Author(s):  
A Martínez ◽  
L M Montuenga ◽  
D R Springall ◽  
A Treston ◽  
F Cuttitta ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Endocrine Cells ◽  
Endocrine Pancreas ◽  
Light And Electron Microscopy ◽  
Regulatory Peptides ◽  
Immunocytochemical Localization ◽  
Serial Sections ◽  
Immunogold Staining ◽  
Granule Membrane ◽  
Amidated Peptide

We studied the distribution of the enzymes that are involved in the post-translational alpha-amidation of regulatory peptides in human endocrine pancreas, using immunocytochemical methods for light and electron microscopy. Immunoreactivity for the two enzymes involved, peptidylglycine alpha-hydroxylating monooxygenase (PHM) and peptidyl-alpha-hydroxyglycine alpha-amidating lyase (PAL), was located in the periphery of the islets of Langerhans and in ductal endocrine cells. Staining of reverse-face serial sections demonstrated that these immunoreactivities co-localize with glucagon but not with pancreatic polypeptide (PP), insulin, or somatostatin. Double immunogold staining for electron microscopy confirmed the previous results and revealed a different localization for each enzyme inside the secretory granule: PHM is present in the central core of the glucagon-containing granules, whereas PAL is predominantly located near the granule membrane. The existence of an amidated peptide, GLP1, in the A-cells explains the presence of peptidylglycine alpha-amidating monooxygenase enzymes (PAM) in these cells. The absence of the enzymes in the PR-cells raises the possibility that a different form of amidating enzyme may be involved in the post-translational processing of this peptide.

Light and electron microscopy localization of chloride ions in cells of Salicornia pacifica var. utahensis

1975 ◽  
Vol 53 (12) ◽  
pp. 1176-1187 ◽  
Author(s):  
W. M. Hess ◽  
D. J. Hansen ◽  
D. J. Weber
Keyword(s):  
Electron Microscopy ◽  
Vascular System ◽  
Silver Chloride ◽  
Light And Electron Microscopy ◽  
Cell Types ◽  
Chloride Ions ◽  
Vascular Bundles ◽  
Silver Acetate ◽  
Parenchyma Cells ◽  
In Cells

Light and electron microscopy was used to determine the distribution of chloride ions in cells and tissues of Salicornia pacifica Standl, var. utahensis (Tidestrom) Munz. Chlorenchyma cells with chloroplasts around the periphery and sclereid-like cells with distinct wall thickenings which extended from the anastomosing vascular system to near the epidermis were present in the cortex. The vascular bundles or stelar strands were surrounded by several layers of large parenchyma cells. Tissues were treated with silver acetate for silver chloride precipitation. Silver chloride precipitation sites were present in all cell types. Precipitation sites were readily evident in the vacuoles but not in other organelles.

scholarly journals Localization of Nestin in Amygdaloid Kindled Rat: An Immunoelectron Microscopic Study

2004 ◽  
Vol 31 (4) ◽  
pp. 514-519 ◽  
Author(s):  
Toshitaka Nakagawa ◽  
Osamu Miyamoto ◽  
Najma A. Janjua ◽  
Roland N. Auer ◽  
Seigo Nagao ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Endothelial Cells ◽  
Piriform Cortex ◽  
Light And Electron Microscopy ◽  
Cell Types ◽  
Perirhinal Cortex ◽  
Intermediate Filament Protein ◽  
Neural Cells ◽  
Nestin Expression ◽  
Filament Protein

Background:Nestin is a class VI intermediate filament protein, expressed during early embryonic development in mammals. Postnatally, nestin and its mRNA are down-regulated and gradually disappear. Recently, nestin expression has been detected in the adult nervous system, and it has been suggested that this protein may be related to neurogenesis, although, its role in the mechanism of neurogenesis is not known.Methods:The present study examined the localization of nestin in CNS tissue of the amygdaloid kindled rat by light and electron microscopy.Results:Kindled animals showed nestin expression mainly in the piriform cortex and the perirhinal cortex. By light microscopy, nestin was shown to be expressed in astrocytes, neurons, and endothelial cells. Electron microscopy demonstrated nestin expression in endothelial cells, astrocytic perivascular end feet, the rare pericyte, neurons and oligodendrocytes.Conclusion:We conclude that epilepsy causes widespread nestin expression in many cell types in the CNS, including non-neural cells.

scholarly journals The Olfactory Mucosa of the Sheep

1970 ◽  
Vol 23 (2) ◽  
pp. 447 ◽  
Author(s):  
Jean E Kratzing
Keyword(s):  
Electron Microscopy ◽  
Lamina Propria ◽  
Light And Electron Microscopy ◽  
Free Edge ◽  
Cell Types ◽  
Olfactory Nerve ◽  
Olfactory Mucosa ◽  
Basal Cells ◽  
Supporting Cells ◽  
Receptor Cells

The olfactory mucosa of the sheep was studied by light and electron microscopy. The epithelium conforms to the general vertebrate pattern and consists of olfactory receptor cells, supporting, and basal cells. The free edge of the epithelium is made up of long microvilli from the supporting cells and olfactory rods of the receptor cells, each carrying 40-50 cilia. All cell types contain large dark granules which may be the site of olfactory pigment. The basement membrane is not visible in light microscopy and is fine and discontinuous in electron microscopy. Bowman's glands are simple, tubular, mucus-secreting glands in the lamina propria. Their cells contain basal granules resembling those in the epithelial cells. The lamina propria also contains bundles of fine, unmyelinated, olfactory nerve fibres which are the proximal continuations of the receptor cells.

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