A Study of Granule Formation in the Bat Parafollicular Cell

1969 ◽  
Vol 5 (2) ◽  
pp. 531-559
Author(s):  
E. A. NUNEZ ◽  
R. P. GOULD ◽  
S. J. HOLT
Keyword(s):  
Endoplasmic Reticulum ◽  
Golgi Complex ◽  
Secretory Granules ◽  
Granular Endoplasmic Reticulum ◽  
Secretory Product ◽  
Central Mass ◽  
Granule Formation ◽  
Cytoplasmic Matrix ◽  
Parafollicular Cell ◽  
Parafollicular Cells

The fine structure of the bat thyroid parafollicular cell has been examined at monthly intervals throughout the hibernating period. During November and December parafollicular cells appear either partly or totally degranulated and intact dense secretory granules are relatively sparse. The degranulated cells exhibit an inconspicuous Golgi complex and relatively few lysosome-type bodies. Few degranulated parafollicular cells are present in thyroid glands from bats collected in January. When found they are characterized by the presence of whorls of cytoplasmic agranular membranes which enclose a central mass of cellular debris. January bat thyroids are characterized by the presence of three different types of parafollicular cell. One type contains no secretory granules. The cytoplasmic matrix of this type is rich in granular endoplasmic reticulum and free ribosomes and its small Golgi complex consists of several slightly dilated saccules. In close proximity to the Golgi complex are numerous small to medium-sized vesicles which often appear to merge with Golgi elements. Such vesicles are considered to represent the vehicle by which secretory product is transferred from the endoplasmic reticulum to the Golgi complex. The second type of parafollicular cell differs from the first in containing large numbers of intact dense secretory granules. It is also characterized by an extensive Golgi complex which appears to be forming new secretory granules, and by a less extensive granular endoplasmic reticulum. The third type of parafollicular cell shows a structure intermediate between the first two. The cytoplasm of all three types of January parafollicular cells contains many structures belonging to the lysosomal-vacuolar system, including autophagic vacuoles, vacuolated dense bodies and multivesicular bodies. By February and March only parafollicular cells of type 2 are observed. They contain few lysosome-like structures. It is concluded that during mid-hibernation (January), parafollicular cells undergo a series of intracellular changes during which new dense secretory granules are produced. Accompanying granule formation is an augmentation of lysosome-like structures which probably serve as a means of digesting debris from previous secretory cycles.

scholarly journals BETA GRANULE FORMATION IN ISOLATED ISLETS OF LANGERHANS

1969 ◽  
Vol 42 (3) ◽  
pp. 695-705 ◽  
Author(s):  
S. L. Howell ◽  
M. Kostianovsky ◽  
P. E. Lacy
Keyword(s):  
Amino Acids ◽  
Endoplasmic Reticulum ◽  
Islets Of Langerhans ◽  
Golgi Complex ◽  
Secretory Granules ◽  
Isolated Islets ◽  
Granule Formation ◽  
Intact Cells ◽  
Rat Islets Of Langerhans ◽  
Electron Lucent

The distribution of radioautographic grains over organelles within the beta cells of rat islets of Langerhans was investigated at various times after pulse labeling of the isolated islets with tritium-labeled amino acids. Ten minutes after the start of labeling most of the grains were situated over the endoplasmic reticulum and cytoplasm; by contrast, 60 min from the start of labeling the majority of the grains were associated with the beta granules. At 20, 30, and 45 minutes after pulse labeling the proportion of grains associated with the Golgi complex was increased two- to three-fold over the 10- or 60-minute values. The distribution of radioautographic grains over granules in the intact cells did not suggest that the electron-lucent type of secretory granules were precursors of the electron-opaque granules. Furthermore, studies of the pattern of grains over granules isolated by centrifugation 60 min after pulse labeling showed no preferential labeling of the electron-lucent type of granule. It is concluded that labeled amino acids are incorporated initially in the endoplasmic reticulum, and that the label subsequently appears in the beta granules. The Golgi complex participates either in the formation of the beta granule or in the translocation of the granule through the cytoplasm of the cell.

scholarly journals Endoplasmic reticulum-to-Golgi transitions upon herpes virus infection

F1000Research ◽  
2018 ◽  
Vol 6 ◽  
pp. 1804 ◽  
Author(s):  
Peter Wild ◽  
Andres Kaech ◽  
Elisabeth M. Schraner ◽  
Ladina Walser ◽  
Mathias Ackermann
Keyword(s):  
Endoplasmic Reticulum ◽  
Nuclear Envelope ◽  
Golgi Complex ◽  
Nuclear Membrane ◽  
Progeny Virus ◽  
Cytoplasmic Matrix ◽  
Outer Nuclear Membrane ◽  
Nuclear Membranes ◽  
Perinuclear Space ◽  
Hsv 1

Background: Herpesvirus capsids are assembled in the nucleus, translocated to the perinuclear space by budding, acquiring tegument and envelope, or released to the cytoplasm via impaired nuclear envelope. One model proposes that envelopment, “de-envelopment” and “re-envelopment” is essential for production of infectious virus. Glycoproteins gB/gH were reported to be essential for de-envelopment, by fusion of the “primary” envelope with the outer nuclear membrane. Yet, a high proportion of enveloped virions generated from genomes with deleted gB/gH were found in the cytoplasm and extracellular space, suggesting the existence of alternative exit routes.Methods: We investigated the relatedness between the nuclear envelope and membranes of the endoplasmic reticulum and Golgi complex, in cells infected with either herpes simplex virus 1 (HSV-1) or a Us3 deletion mutant thereof, or with bovine herpesvirus 1 (BoHV-1) by transmission and scanning electron microscopy, employing freezing technique protocols.Results:  The Golgi complex is a compact entity in a juxtanuclear position covered by a membrane on thecisface. Golgi membranes merge with membranes of the endoplasmic reticulum forming an entity with the perinuclear space. All compartments contained enveloped virions. After treatment with brefeldin A, HSV-1 virions aggregated in the perinuclear space and endoplasmic reticulum, while infectious progeny virus was still produced.Conclusions: The data suggest that virions derived by budding at nuclear membranes are intraluminally transported from the perinuclear space via Golgi -endoplasmic reticulum transitions into Golgi cisternae for packaging. Virions derived by budding at nuclear membranes are infective like Us3 deletion mutants, which  accumulate in the perinuclear space. Therefore, i) de-envelopment followed by re-envelopment is not essential for production of infective progeny virus, ii) the process taking place at the outer nuclear membrane is budding not fusion, and iii) naked capsids gain access to the cytoplasmic matrix via impaired nuclear envelope as reported earlier.

scholarly journals CYTOLOGICAL STUDIES ON TWO FUNCTIONAL HEPATOMAS

1962 ◽  
Vol 15 (2) ◽  
pp. 289-312 ◽  
Author(s):  
Edward Essner ◽  
Alex B. Novikoff
Keyword(s):  
Endoplasmic Reticulum ◽  
Acid Phosphatase ◽  
Golgi Apparatus ◽  
Phosphatase Activity ◽  
Acid Phosphatase Activity ◽  
Secretory Granules ◽  
Dynamic State ◽  
Secretory Product ◽  
Electron Microscopic ◽  
Golgi Membranes

The Reuber hepatoma H-35 and Morris hepatoma 5123 have been studied by electron microscopy and by cytochemical staining methods for a number of phosphatases. These studies emphasize the resemblances of the two tumors to rat liver, but they also indicate distinctive features in each of the three tissues. Secretory product accumulates within the cisternae of the Golgi apparatus that dilate to form the Golgi vacuoles. The vacuoles apparently separate, and secretory material undergoes further condensation within them. These "secretory vacuoles" possess acid phosphatase activity and may thus be considered lysosomes. The membranes of the Golgi apparatus are without acid phosphatase activity but show high levels of thiaminepyrophosphatase activity. The endoplasmic reticulum also hydrolyzes thiaminepyrophosphate but at a lower rate; it hydrolyzes the diphosphates of uridine, guanosine, and inosine rapidly. These observations and the electron microscopic images are consistent with the view that the cytomembranes are in a dynamic state of flux, movement, and transformation in the living cell, and that smooth surfaced derivatives of the endoplasmic reticulum become refashioned into the Golgi membranes as the Golgi membranes are being refashioned into those that delimit secretory vacuoles. The variations encountered in the two hepatomas are described. The electron microscope literature dealing with the relations of the Golgi apparatus to secretory granules, on the one hand, and the endoplasmic reticulum, on the other, is reviewed briefly.

scholarly journals Immunocytochemical localization of amylase and chymotrypsinogen in the exocrine pancreatic cell with special attention to the Golgi complex.

1979 ◽  
Vol 82 (3) ◽  
pp. 697-707 ◽  
Author(s):  
J J Geuze ◽  
J W Slot ◽  
K T Tokuyasu
Keyword(s):  
Golgi Complex ◽  
Functional Unit ◽  
Secretory Granules ◽  
Pancreatic Tissue ◽  
Frozen Sections ◽  
Cytoplasmic Matrix ◽  
Pancreatic Cell ◽  
Peripheral Area ◽  
Ultrathin Frozen Sections ◽  
Fasted Rats

Affinity-purified, monospecific rabbit antibodies against rat pancreatic alpha-amylase and bovine pancreatic alpha-chymotrypsinogen were used for immunoferritin observations of ultrathin frozen sections of mildly fixed exocrine pancreatic tissue from secretion-stimulated (pilocarpine) rats and from overnight-fasted rats and guinea pigs. The labeling patterns for both antibodies were qualitatively alike: Labeling occurred in (a) the cisternae of the rough endoplasmic reticulum (RER) including the perinuclear cisterna, in (b) the peripheral area between the RER and cis-Golgi face, and (c) all Golgi cisternae, condensing vacuoles, and secretory granules. Labeling of cytoplasmic matrix was negligible. Structures that appeared to correspond to rigid lamellae were unlabeled. Differences in labeling intensities indicated that concentration of the zymogens starts at the boundary of the RER and cis-side of the Golgi complex. These data support the view that the Golgi cisternae are involved in protein processing in both stimulated and unstimulated cells and that Golgi cisternae and condensing vacuoles constitute a functional unit.

scholarly journals Ultrastructural Evaluation of Thyroid Parafollicular Cells of Pigs with Naturally Occurring Atrophic Rhinitis

1970 ◽  
Vol 7 (2) ◽  
pp. 171-185 ◽  
Author(s):  
A.W. Fetter ◽  
C.C. Capen
Keyword(s):  
Endoplasmic Reticulum ◽  
Golgi Apparatus ◽  
Secretory Granules ◽  
Atrophic Rhinitis ◽  
Secretory Cycle ◽  
Naturally Occurring ◽  
Parafollicular Cells ◽  
Significant Difference ◽  
And Storage

The thyroid parafollicular cells of 4-month-old control pigs and pigs with naturally occurring atrophic rhinitis were evaluated ultrastructurally. Significant difference was not observed in populations of parafollicular cells between the 2 groups of pigs. Parafollicular cells occurred in actively synthesizing and storage phases of the secretory cycle in both groups. Actively synthesizing cells had a well-developed endoplasmic reticulum, aggregated ribosomes, and prominent Golgi apparatuses with prosecretory granules. The cytoplasm of parafollicular cells in the storage phase was packed with electron-dense secretory granules. The Golgi apparatus and ergastoplasm were less prominent. There was no evidence to suggest that an interference in the synthesis or release of thyrocalcitonin by parafollicular cells was of criologic importance in the pathogenesis of atrophic rhinitis.

scholarly journals The Development of the Cnidoblasts of Hydra

1959 ◽  
Vol 5 (3) ◽  
pp. 441-452 ◽  
Author(s):  
David B. Slautterback ◽  
Don W. Fawcett
Keyword(s):  
Endoplasmic Reticulum ◽  
Golgi Complex ◽  
Interstitial Cell ◽  
Complex Cell ◽  
Electron Microscopic ◽  
Cytoplasmic Matrix ◽  
Virtual Absence ◽  
Cytological Characteristics ◽  
Mode Of Attachment

The general histological organization of Hydra is reviewed and electron microscopic observations are presented which bear upon the nature of the mesoglea, the mode of attachment of the contractile processes of the musculo-epithelial cells, and the cytomorphosis of the cnidoblasts. Particular attention is devoted to the changes in form and distribution of the cytoplasmic organelles in the course of nematocyst formation. The undifferentiated interstitial cell is characterized by a small Golgi complex, few mitochondria, virtual absence of the endoplasmic reticulum, and a cytoplasmic matrix crowded with fine granules presumed to be ribonucleoprotein. These cytological characteristics persist through the early part of the period of interstitial cell proliferation which leads to formation of clusters of cnidoblasts. With the initiation of nematocyst formation in the cnidoblasts, numerous membrane-bounded vesicles appear in their cytoplasm. These later coalesce to form a typical endoplasmic reticulum with associated ribonucleoprotein granules. During the ensuing period of rapid growth of the nematocyst the reticulum becomes very extensive and highly organized. Finally, when the nematocyst has attained its full size, the reticulum breaks up again into isolated vesicles. The Golgi complex remains closely applied to the apical pole of the nematocyst throughout its development and apparently contributes to its enlargement by segregating formative material in vacuoles whose contents are subsequently incorporated in the nematocyst. The elaboration of this complex cell product appears to require the cooperative participation of the endoplasmic reticulum and the Golgi complex. Their respective roles in the formative process are discussed.

scholarly journals High resolution analysis of the secretory pathway in mammotrophs of the rat anterior pituitary.

1981 ◽  
Vol 91 (1) ◽  
pp. 240-246 ◽  
Author(s):  
M M Salpeter ◽  
M G Farquhar
Keyword(s):  
High Resolution ◽  
Golgi Complex ◽  
Secretory Granules ◽  
Female Rats ◽  
Secretory Process ◽  
Pituitary Cells ◽  
Secretory Product ◽  
Electron Microscope Autoradiography ◽  
New Findings ◽  
Density Analysis

The secretory process in pituitary mammotrophs was analyzed by quantitative electron microscope autoradiography. Dispersed pituitary cells from estrogen-treated female rats were subjected to pulse-labeling with [3H]leucine (5 min) followed by a chase incubation of up to 4 h. Autoradiograms were prepared using fine-grained emulsion (Kodak 129-01), and analyzed using a three-step "mask analysis' procedure: (a) the distribution of autoradiographic grains is determined as in a simple grain density analysis; (b) masks (transparent overlays) are used to generate expected grains from assumed sources; and (c) a computer program compares these two distributions and varies the expected distribution to match the observed distribution, thereby identifying the radioactive sources in the tissue. The overall route of intracellular transport of prolactin from rough endoplasmic reticulum (ER) leads to Golgi complex leads to immature secretory granules leads to mature secretory granules was as established in previous studies. However, by use of the high resolution emulsion and method of analysis, the precision with which label could be localized within individual source compartments was much greater and the time resolution was much sharper than achieved previously using Ilford L4 emulsion and simple grain density analysis. The main new findings were as follows: (a) the ER was essentially drained of radioactivity by 30 min, the Golgi complex by 1 h, and the immature secretory granules by 2h postpulse. This indicates that the secretory product (prolactin) is rapidly and efficiently transported out of these compartments. (b) approximately 30% of the total radioactivity remains located in the ground cytoplasm over the entire postpulse period examined (up to 4 h), and by 30 min postpulse the grain density in the ground cytoplasm exceeded that of the ER. This indicates the ability to resolve ER-associated label (presumably associated mainly with secretory products) from the cytoplasmic label (presumably associated with nonsecretory proteins). (c) the specific activity of immature secretory granules was much greater than previously appreciated; at 1 h postpulse it was greater than 200 times that of the adjacent Golgi complex cisternae. This large dynamic range in observed grain density demonstrates the ability to effectively correct for radiation spread and thus to detect with great accuracy high concentration of label even from very small structures (20-100 nm) which constitute a small percentage (less than 1%) of the total cell area.

scholarly journals THE BIOSYNTHESIS, INTRACELLULAR TRANSPORT, AND PACKAGING OF MELANOCYTE-STIMULATING PEPTIDES IN THE AMPHIBIAN PARS INTERMEDIA

1972 ◽  
Vol 53 (3) ◽  
pp. 642-653 ◽  
Author(s):  
C. R. Hopkins
Keyword(s):  
Endoplasmic Reticulum ◽  
Rough Endoplasmic Reticulum ◽  
Intracellular Transport ◽  
Secretory Granules ◽  
Extended Period ◽  
Pars Intermedia ◽  
Secretory Product ◽  
Intracellular Location ◽  
Parenchymal Cells

Experiments in which glycine-3H has been introduced into excised neurointermediate lobes of Xenopus laevis incubated in a modified Krebs-Ringer bicarbonate medium have shown that ∼ 50% of the incorporated radioactivity is present in small peptides which have an electrophoretic mobility characteristic of the melanocyte-stimulating (MSH) peptides shown to be elaborated within the tissue. Based on these results and the demonstration that a discrete ∼ 7 min pulse of the label can be introduced into the tissue, electron microscope radioautography has been employed to follow the subcellular events concerned with the synthesis, intracellular transport, and packaging of the labeled secretory product. Together, these studies indicate that the newly synthesized material arises in peptide form, rather than as part of a larger prohormone molecule, on the ribosomes of the rough endoplasmic reticulum within the parenchymal cells of the intermediate portion of the lobe. A proportion is then incorporated into and remains for an extended period within the intracisternal granules which are a feature of the rough endoplasmic reticulum within these cells in vitro Most (∼ 60%) of the labeled secretory product, however, is transferred to the Golgi complex within 30 min and, within a further 10 min, becomes packaged into small (∼ 200 mµ) electron-opaque secretory granules. It is probable that under the conditions employed these granules represent the final intracellular location of secretory product before it is released

scholarly journals Small disulfide loops in peptide hormones mediate self-aggregation and secretory granule sorting

2021 ◽  
Author(s):  
Jennifer Reck ◽  
Nicole Beuret ◽  
Erhan Demirci ◽  
Cristina Prescianotto-Baschong ◽  
Martin Spiess
Keyword(s):  
Endoplasmic Reticulum ◽  
Secretory Granule ◽  
Secretory Granules ◽  
Peptide Hormones ◽  
Secreted Proteins ◽  
Reporter Protein ◽  
Granule Formation ◽  
Functional Amyloids ◽  
Golgi Network ◽  
Self Aggregation

ABSTRACTUnlike constitutively secreted proteins, peptide hormones are stored in densely packed secretory granules, before regulated release upon stimulation. Secretory granules are formed at the trans-Golgi network (TGN) by self-aggregation of prohormones as functional amyloids. The nonapeptide hormone vasopressin, which forms a small disulfide loop, was shown to be responsible for granule formation of its precursor in the TGN as well as for toxic fibrillar aggregation of unfolded mutants in the endoplasmic reticulum (ER). Several other hormone precursors also contain similar small disulfide loops suggesting their function as a general device to mediate aggregation for granule biogenesis. To test this hypothesis, we studied the capacity of small disulfide loops of different hormone precursors to mediate aggregation in the ER and the TGN. They indeed induced ER aggregation although to different extents in Neuro-2a and COS-1 cells. Fused to a constitutively secreted reporter protein, they also promoted sorting into secretory granules, enhanced stimulated secretion, and increased Lubrol insolubility in AtT20 cells. These results support the hypothesis that small disulfide loops act as novel signals for secretory granule biogenesis and sorting by self-aggregation.

Fine structure of the vitteline cells in the cestode Proteocephalus longicollis (proteocephalidea)

1978 ◽  
Vol 36 (2) ◽  
pp. 442-443
Author(s):  
Z. Swiderski ◽  
R. D. Eklu-natey ◽  
L. Subilia ◽  
H. Huggel
Keyword(s):  
Endoplasmic Reticulum ◽  
Lipid Droplets ◽  
Secretory Activity ◽  
Granular Endoplasmic Reticulum ◽  
Secretory Cells ◽  
Cytoplasmic Matrix ◽  
Shell Protein ◽  
Vitelline Cells ◽  
Shell Globule ◽  
Spherical Nuclei

The mature vitelline cells of Proteocephalus longicollis (Zeder, 1800) are ovoid or spherical and measure about 30μm in diameter. They represent the holocrine type of secretory cells.The spherical nuclei, about 10μm in diameter, are localized in the central part of the cell. They contain more or less prominent nucleoli enclosed in the moderately electrondense nucleoplasm (Fig. 1).The cytoplasm (Fig. 2, 3, 4) is packed with numerous shell globules of heterogenous type, large lipid droplets, and a few glycogen islands composed mainly of α-glycogen rosettes.The remaining granular cytoplasmic matrix (Fig. 3, 4) contains: (a) numerous polysomes, (b) cysternae of granular endoplasmic reticulum, (c) several mitochondria, and (d) extended Golgi regions, composed of vesicles of different sizes and density.The extensive development of granular endoplasmic reticulum (GER) and Golgi complexes indicates high secretory activity of these cells. Both Golgi and GER are evidently engaged in shell globule formation and are considered therefore to function as the shell-protein producing units

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