The fate of larval chondrocytes during the metamorphosis of the epibranchial in the salamander, Eurycea bislineata

Development ◽  
1985 ◽  
Vol 88 (1) ◽  
pp. 71-83
Author(s):  
P. Alberch ◽  
G. A. Lewbart ◽  
Emily A. Gale
Keyword(s):  
Endoplasmic Reticulum ◽  
Cell Death ◽  
Thyroid Hormones ◽  
Light Microscopy ◽  
Rough Endoplasmic Reticulum ◽  
Thyroxine Treatment ◽  
Nuclear Degeneration ◽  
Tissue Manipulation ◽  
Eurycea Bislineata

The metamorphosis of the epibranchial cartilage, a skeletal component of the hyobranchial apparatus, in the salamander Eurycea bislineata entails a combination of the reabsorption of a larval cartilaginous element with the simultaneous genesis of an adult cartilage in the same place. In this study we focus on the fate of the larval chondrocytes. Two hypotheses are considered: one, larval cells simply die off during metamorphosis, or, alternatively, they dedifferentiate and participate in the formation of the adult element. Thyroxine treatment and experimental tissue manipulation coupled with measurements of thyroxine levels using radioimmunoassay show that, within 24 h after T4 treatment, larval chondrocytes in the epibranchials exhibit large autophagocytic vacuoles, disruption of the rough endoplasmic reticulum, abnormally shaped mitochondria, abundance of lysosomes and nuclear degeneration, all symptoms of the onset of cell death. In conclusion, evidence from light microscopy, TEM and SEM show that the larval chondrocytes in response to rising levels of thyroid hormones undergo a process of lysosomal autophagocytosis and do not participate in the formation of adult structures.

scholarly journals Ultrastructural studies of the hemocytes of Panstrongylus megistus (Hemiptera: Reduvidae)

1989 ◽  
Vol 84 (2) ◽  
pp. 171-188 ◽  
Author(s):  
Margherita A. Barracco ◽  
Clarice T. Loch
Keyword(s):  
Endoplasmic Reticulum ◽  
Light Microscopy ◽  
Rough Endoplasmic Reticulum ◽  
Lipid Droplets ◽  
Panstrongylus Megistus ◽  
Ultrastructural Studies ◽  
Hemocyte Count

Ultrastructural analyses revealed the presence of six hemocyte types in the hemolymph of Panstrogylus megistus, partially confirming our previous results obtained through light microscopy. Prohemocytes: small, round hemocytes with a thin cytoplasm layer, espcieally rich in free ribosomes and poor in membranous systems. Plasmatocytes: polymorphic cells, whose cytoplasm contains many lysosomes and a well developed rough endoplasmic reticulum (RER).They are extremely phagocytic. Sometimes, they show a large vacuolation. Granulocytes: granular hemocytes whose granules show different degrees of electrondensity. Most of them, have an internal structuration. Coagulocytes: oval or elongated hemocytes, which show pronounced perinuclear cisternae as normally observed in coagulocytes. The cytoplasm is usually electrondense, poor in membranous systems and contains many labile granules. Oenocytoids: large and very stable hemocytes, whose homogeneous cytoplasme is rich in loose ribosomes and poor in membranous systems. Adipohemocytes: large cells, containing several characteristic lipid droplets. The cytoplasm is also rich in glycogen, RER and large mitochondria. The total and differential hemocyte count (THC and DHC) were also calculated for this reduviid. THC increases from 2,900 hemocytes/cubic millimeter of hemolymph in the 4th intar to 4,350 in the 5th and then, decreases to 1,950 in the adults. Plasmatocytes and coagulocytes are the predominant hemocyte types.

Localization of Alkaline Phosphatase in Marrow Cells

1973 ◽  
Vol 31 ◽  
pp. 692-693
Author(s):  
Anne D. Geddes ◽  
Mary E. Kirchen ◽  
G. June Marshall
Keyword(s):  
Alkaline Phosphatase ◽  
Endoplasmic Reticulum ◽  
Light Microscopy ◽  
Rough Endoplasmic Reticulum ◽  
Golgi Complex ◽  
Significant Marker ◽  
Leukocyte Alkaline Phosphatase ◽  
Marrow Cells

Leukocyte alkaline phosphatase(LAP) is potentially a significant marker for following the maturation sequence of normal and abnormal neutrophils. This enzyme can be localized in the rough endoplasmic reticulum (rer) and in the Golgi complex of immature neutrophils but it has been very difficult to demonstrate LAP activity in the granules of mature neutrophils. This observation presents a dilemma since LAP is present in higher concentrations in mature as opposed to immature neutrophils as demonstrated by biochemical and light microscopy methods.In an attempt to solve this problem, variations on the routine methods for demonstrating LAP activity were explored. Acetone, formaldehyde, methanol and gluteraldehyde were used as fixatives.

Organization of the thyroglobulin polysome, studied in Endoplasmic Reticulum surface views of rough endoplasmic reticulum in cultured rat thyroid cells

1990 ◽  
Vol 48 (3) ◽  
pp. 546-547
Author(s):  
A. Kent Christensen ◽  
Hayden G. Coon
Keyword(s):  
Endoplasmic Reticulum ◽  
Thyroid Gland ◽  
Thyroid Hormones ◽  
Cross Section ◽  
Electron Micrographs ◽  
Rough Endoplasmic Reticulum ◽  
Thyroid Cells ◽  
En Face ◽  
Face View ◽  
Rat Thyroid

Thyroglobulin is synthesized in the thyroid gland and is subsequently degraded to provide thyroid hormones. Rat thyroglobulin is made up of two identical 330 kD subunits, and the mRNA for each subunit contains about 8,500 nucleotides. Since polysomes have approximately one ribosome for each 90-100 nucleotides of mRNA, a polysome of about 85-95 ribosomes would be expected for thyroglobulin. We have been interested in how this very large polysomes is organized on the membranes of the rough endoplasmic reticulum (RER).It is well known that bound polysomes assume characteristic shapes on the surface of the RER, resembling beads on a string arranged in circles, spirals, loops, hairpins or other forms. These polysomal shapes can be observed in conventional electron micrographs when the membranes of the RER are seen in surface or en face view, rather than in the usual cross section. Clearcut surface views are infrequent, but the likelihood of seeing them is greatly improved when flattened cells in culture are sectioned in the plane of the cell, since the RER in a flattened cell tends to be oriented in that plane.

Light and electron microscope studies of cytoplasmic aggregates formed in barley cells in response to Erysiphe graminis

1976 ◽  
Vol 54 (14) ◽  
pp. 1647-1655 ◽  
Author(s):  
W. R. Bushnell ◽  
R. J. Zeyen
Keyword(s):  
Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Electron Microscope ◽  
Light Microscopy ◽  
Rough Endoplasmic Reticulum ◽  
Rapid Development ◽  
Epidermal Cells ◽  
Erysiphe Graminis ◽  
Synthetic Activity ◽  
Golgi Bodies

Cytoplasmic aggregates that formed in susceptible barley epidermal cells 11-12 h after inoculation with Erysiphe graminis were examined by light microscopy in living specimens and by electron microscopy in fixed specimens. Rapid development of the aggregate (5–10 min) suggested that cytoplasm migrated to the site of each aggregation. The aggregate contained features generally associated with areas of high metabolic and synthetic activity: abundant mitochondria, rough endoplasmic reticulum (associated with smooth cisternae), Golgi bodies, and polyribosomes. Leucoplasts and nuclei were sometimes near aggregates but not consistently. Microbodies and osmiophilic spherosomes were not present.

scholarly journals An immunocytochemical study of TSH beta storage in rat thyroidectomy cells with and without D or L thyroxine treatment.

1976 ◽  
Vol 24 (11) ◽  
pp. 1140-1149 ◽  
Author(s):  
G C Moriarty ◽  
R B Tobin
Keyword(s):  
Endoplasmic Reticulum ◽  
Rough Endoplasmic Reticulum ◽  
Binding Sites ◽  
Secretory Granules ◽  
Thyroid Stimulating Hormone ◽  
Immunocytochemical Staining ◽  
Immunocytochemical Study ◽  
Beta Chain ◽  
Thyroxine Treatment ◽  
Tsh Cells

Binding sites to the beta chain of thyroid stimulating hormone (TSH) were localized in pituitaries of thyroidectomized rats. Immunocytochemical staining was observed in hypertrophied TSH cells ("thyroidectomy cells") and primarily located in dilated rough endoplasmic reticulum. Staining was also found on the few secretory granules and on some of the intracisternal granules. Some of the thyroidectomy cells stained intensely, while others exhibited very little staining. When thyroidectomized rats were treated with thyroxine 4 days before death, the TSH cells contained more secretory granules, and the intracisternal granules were larger and more numerous. L-thyroxine was 10 times as potent as D-thyroxine in promoting the build-up of granules. Both types of granules stained intensely.

Modification of Pineal Ultrastructure by Exogenous Hormones

1967 ◽  
Vol 25 ◽  
pp. 170-171
Author(s):  
R. A. Turner ◽  
A. E. Rodin ◽  
D. K. Roberts
Keyword(s):  
Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Rough Endoplasmic Reticulum ◽  
Estradiol Benzoate ◽  
Female Rats ◽  
List Type ◽  
Type Number ◽  
Pregnant Rats ◽  
Gonadal Atrophy ◽  
Pineal Ultrastructure

There have been many reports which establish a relationship between the pineal and sexual structures, including gonadal hypertrophy after pinealectomy, and gonadal atrophy after injection of pineal homogenates or of melatonin. In order to further delineate this relationship the pineals from 5 groups of female rats were studied by electron microscopy:ControlsPregnant ratsAfter 4 weekly injections of 0.1 mg. estradiol benzoate.After 8 daily injections of 150 mcgm. melatonin (pineal hormone).After 8 daily injections of 3 mg. serotonin (melatonin precursor).No ultrastructural differences were evident between the control, and the pregnancy and melatonin groups. However, the estradiol injected animals exhibited a marked increase in the amount and size of rough endoplasmic reticulum within the pineal cells.

Membrane-associated microtubular areays induced in proximal myelinated processes of dorsal root ganglia by large doses of vitamin B6

1986 ◽  
Vol 44 ◽  
pp. 368-369
Author(s):  
V.J. Montpetit ◽  
S. Dancea ◽  
L. Tryphonas ◽  
D.F. Clapin
Keyword(s):  
Animal Model ◽  
Endoplasmic Reticulum ◽  
Dorsal Root Ganglia ◽  
Rough Endoplasmic Reticulum ◽  
Dorsal Root ◽  
Vitamin B6 ◽  
Morphological Changes ◽  
Model System ◽  
Sensory Nerves ◽  
Peripheral Sensory

Very large doses of pyridoxine (vitamin B6) are neurotoxic in humans, selectively affecting the peripheral sensory nerves. We have undertaken a study of the morphological and biochemical aspects of pyridoxine neurotoxicity in an animal model system. Early morphological changes in dorsal root ganglia (DRG) associated with pyridoxine megadoses include proliferation of neurofilaments, ribosomes, rough endoplasmic reticulum, and Golgi complexes. We present in this report evidence of the formation of unique aggregates of microtubules and membranes in the proximal processes of DRG which are induced by high levels of pyridoxine.

CUX1 controls endoplasmic reticulum stress and autophagy related cell death

2016 ◽  
Vol 54 (12) ◽  
pp. 1343-1404
Author(s):  
G Metzger ◽  
P Di Fazio ◽  
DK Bartsch ◽  
T Gress ◽  
TT Wissniowski
Keyword(s):  
Endoplasmic Reticulum ◽  
Cell Death ◽  
Endoplasmic Reticulum Stress ◽  
Related Cell
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