The Role of Endoplasmic Reticulum in the Repair of Amoeba Nuclear Envelopes Damaged Microsurgically

1974 ◽  
Vol 14 (2) ◽  
pp. 421-437
Author(s):  
C. J. FLICKINGER
Keyword(s):  
Endoplasmic Reticulum ◽  
Nuclear Envelope ◽  
Rough Endoplasmic Reticulum ◽  
Repair Process ◽  
Nuclear Membranes ◽  
Normal Configuration ◽  
Layer Characteristic ◽  
The Relationship ◽  
Coated Slide

The nuclear envelopes of amoebae were damaged microsurgically, and the fate of the lesions was studied with the electron microscope. Amoebae were placed on the surface of an agar-coated slide. Using a glass probe, the nucleus was pushed from an amoeba, damaged with a chopping motion of the probe, and reinserted into the amoeba. Cells were prepared for electron microscopy at intervals of between 10 min and 4 days after the manipulation. Nuclear envelopes studied between 10 min and 1 h after the injury displayed extensive damage, including numerous holes in the nuclear membranes. Beginning 15 min after the manipulation, pieces of rough endoplasmic reticulum intruded into the holes in the nuclear membranes. These pieces of rough endoplasmic reticulum subsequently appeared to become connected to the nuclear membranes at the margins of the holes. By 1 day following the injury, many cells had died, but the nuclear membranes were intact in those cells that survived. The elaborate fibrous lamina or honeycomb layer characteristic of the amoeba nuclear envelope was resistant to early changes after the manipulation. Patches of disorganization of the fibrous lamina were present 5 h to 1 day after injury, but the altered parts showed evidence of progress toward a return to normal configuration by 4 days after the injury. It is proposed that the rough endoplasmic reticulum participates in the repair of injury to the nuclear membranes. The similarity of this repair process to reconstitution of the nuclear envelope in telophase of mitosis is noted, and the relationship between the nuclear envelope and the rough endoplasmic reticulum is discussed.

scholarly journals DEVELOPMENT OF ENDOGENOUS PEROXIDASE IN FETAL RAT SUBMANDIBULAR GLAND

1973 ◽  
Vol 21 (1) ◽  
pp. 42-50 ◽  
Author(s):  
SHOHEI YAMASHINA ◽  
TIBOR BARKA
Keyword(s):  
Endoplasmic Reticulum ◽  
Nuclear Envelope ◽  
Submandibular Gland ◽  
Rough Endoplasmic Reticulum ◽  
Peroxidase Activity ◽  
Secretory Granules ◽  
Prenatal Development ◽  
Reaction Products ◽  
Cell Type ◽  
Endogenous Peroxidase

The prenatal development of endogenous peroxidase activity in the submandibular gland of rat was investigated by means of the diaminobenzidine-H2O2 histochemical method. The submandibular gland of a 16-day-old fetus was composed of cords of uniform, undifferentiated cells which contained no secretory granules and revealed no peroxidase activity. Peroxidase activity first appeared at the 17th day of gestation in the cisternae of the rough endoplasmic reticulum and nuclear envelope in a few cells. At the 18th day of gestation cells which exhibited reaction products in the rough endoplasmic reticulum and nuclear envelope also contained secretory granules with a strong peroxidase activity. During the last days of gestation the number of peroxidase positive cells, which contained numerous secretory granules, increased. The peroxidase-containing cells are the immediate precursors of the proacinar cells of early postnatal stages. During the same time period, when the peroxidase-containing cells differentiated, a second cell type also differentiated in the cellular cords. The development of this cell type was marked by the appearance of secretory granules stainable with toluidine blue. Through the prenatal development, this cell type revealed no peroxidase activity and was identified with the terminal tubule cell of the newborn. The morphologic and cytochemical findings indicate that terminal tubule cells and proacinar cells are committed cells; the former differentiate toward 2nd order intercalated duct cells and the latter transform to mature acinar cells.

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.

The polypeptides of rat liver nuclear envelope. II. Comparison of rat liver nuclear membrane polypeptides with those of the rough endoplasmic reticulum

1980 ◽  
Vol 43 (1) ◽  
pp. 269-277
Author(s):  
J.C. Richardson ◽  
A.H. Maddy
Keyword(s):  
Endoplasmic Reticulum ◽  
Rat Liver ◽  
Rough Endoplasmic Reticulum ◽  
Nuclear Membrane ◽  
Relative Proportion ◽  
Membrane System ◽  
Membrane Systems ◽  
Nuclear Membranes ◽  
Cytoplasmic Surface ◽  
Triton X

Nuclear envelopes are separated into pore-lamina and membrane sub-fractions by extraction in 2.0% Triton X-100 followed by pelleting of the pore-laminae. The polypeptides of these subfractions are then compared with those from isolated rough endoplasmic reticulum. The dispositions of individual polypeptides in the cytoplasmic surface of nuclear envelopes and rought endoplasmic reticulum were studied by lactoperoxidase-catalysed iodination. These studies show that although the nuclear membranes exhibit several homologies with the Triton-soluble polypeptides of the rough endoplasmic reticulum the relative proportion of individual polypeptides within the two systems are very largely different. The cytoplasmic surfaces of the 2 membrane systems show only 2 obvious homologies at 105 000 and 15 000 mol. wt and the overall impression is that, at least in rat liver, the outer nuclear membrane is very substantially differentiated from rough endoplasmic reticulum. It is concluded that the nuclear membranes may not be regarded as a mere continuum of the endoplasmic reticulum, but should be seen as a highly specialized membrane system in their own right.

Ultrastructural changes in nuclear membranes and organelle associations during mitosis of the aquatic fungus Entophlyctis sp.

1975 ◽  
Vol 53 (7) ◽  
pp. 627-646 ◽  
Author(s):  
Martha J. Powell
Keyword(s):  
Endoplasmic Reticulum ◽  
Nuclear Envelope ◽  
Nuclear Division ◽  
Ultrastructural Changes ◽  
Aquatic Fungus ◽  
Electron Microscopic ◽  
Mitotic Apparatus ◽  
Inner Membrane ◽  
Nuclear Membranes ◽  
Spindle Microtubules

Electron microscopic observations on an endobiotic chytrid, Entophlyctis sp., have revealed a mitotic apparatus which is presently unique among fungi. Daughter nuclear envelopes are reconstituted from cisternae apparently proliferated by the inner membrane of the nuclear envelope. Before nuclear division, centrioles replicate and migrate to the poles of the nucleus. Large pores appear at this time in a depression of the nuclear envelope opposite the paired centrioles. This region of the envelope fragments and leaves polar fenestrae as spindle microtubules appear in the nucleus. The inner membrane of the nuclear envelope then invaginates and proliferates cisternae until a layer of inner membrane cisternae lines the original nuclear envelope at late metaphase. Connections between the inner membrane of the original nuclear envelope and the cisternae persist until telophase. As the spindle elongates and the inner membrane cisternae fuse centripetally to form a reticulum around the chromatin mass, the original nuclear envelope opens more at the poles. The reticulum becomes the nuclear envelope of the new daughter nuclei. When the original envelope finally disperses, it is distinguishable from the endoplasmic reticulum only by the presence of pores. Microbodies are consistently associated with the original nuclear envelope and appear adjacent to the new daughter envelopes at the end of telophase. Densely staining arms project from the sides of the primary centrioles toward the polar mitochondria.

scholarly journals A role for Rab5 in structuring the endoplasmic reticulum

2007 ◽  
Vol 178 (1) ◽  
pp. 43-56 ◽  
Author(s):  
Anjon Audhya ◽  
Arshad Desai ◽  
Karen Oegema
Keyword(s):  
Endoplasmic Reticulum ◽  
Caenorhabditis Elegans ◽  
Nuclear Envelope ◽  
Rab Gtpases ◽  
C Elegans ◽  
Rab Family ◽  
Kinetics Of

The endoplasmic reticulum (ER) is a contiguous network of interconnected membrane sheets and tubules. The ER is differentiated into distinct domains, including the peripheral ER and nuclear envelope. Inhibition of two ER proteins, Rtn4a and DP1/NogoA, was previously shown to inhibit the formation of ER tubules in vitro. We show that the formation of ER tubules in vitro also requires a Rab family GTPase. Characterization of the 29 Caenorhabditis elegans Rab GTPases reveals that depletion of RAB-5 phenocopies the defects in peripheral ER structure that result from depletion of RET-1 and YOP-1, the C. elegans homologues of Rtn4a and DP1/NogoA. Perturbation of endocytosis by other means did not affect ER structure; the role of RAB-5 in ER morphology is thus independent of its well-studied requirement for endocytosis. RAB-5 and YOP-1/RET-1 also control the kinetics of nuclear envelope disassembly, which suggests an important role for the morphology of the peripheral ER in this process.

scholarly journals Nuclear Envelope Proteins Modulating the Heterochromatin Formation and Functions in Fission Yeast

Cells ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 1908 ◽  
Author(s):  
Yasuhiro Hirano ◽  
Haruhiko Asakawa ◽  
Takeshi Sakuno ◽  
Tokuko Haraguchi ◽  
Yasushi Hiraoka
Keyword(s):  
Endoplasmic Reticulum ◽  
Nuclear Envelope ◽  
Fission Yeast ◽  
Histone Deacetylase ◽  
Nuclear Pore Complex ◽  
Molecular Mechanisms ◽  
Nuclear Pore ◽  
Double Membrane ◽  
Heterochromatin Formation ◽  
Nuclear Membranes

The nuclear envelope (NE) consists of the inner and outer nuclear membranes (INM and ONM), and the nuclear pore complex (NPC), which penetrates the double membrane. ONM continues with the endoplasmic reticulum (ER). INM and NPC can interact with chromatin to regulate the genetic activities of the chromosome. Studies in the fission yeast Schizosaccharomyces pombe have contributed to understanding the molecular mechanisms underlying heterochromatin formation by the RNAi-mediated and histone deacetylase machineries. Recent studies have demonstrated that NE proteins modulate heterochromatin formation and functions through interactions with heterochromatic regions, including the pericentromeric and the sub-telomeric regions. In this review, we first introduce the molecular mechanisms underlying the heterochromatin formation and functions in fission yeast, and then summarize the NE proteins that play a role in anchoring heterochromatic regions and in modulating heterochromatin formation and functions, highlighting roles for a conserved INM protein, Lem2.

scholarly journals NUCLEAR MEMBRANES FROM MAMMALIAN LIVER

1970 ◽  
Vol 46 (2) ◽  
pp. 379-395 ◽  
Author(s):  
Werner W. Franke ◽  
Barbara Deumling ◽  
Baerbel Ermen ◽  
Ernst-Dieter Jarasch ◽  
Hans Kleinig
Keyword(s):  
Endoplasmic Reticulum ◽  
Nuclear Envelope ◽  
Nuclear Membrane ◽  
Cytochrome B5 ◽  
Buoyant Density ◽  
Nuclear Pore ◽  
Nuclear Membranes ◽  
Dna And Rna ◽  
Mammalian Liver ◽  
Order Of Magnitude

Nuclear membranes were isolated from rat and pig liver by sonication of highly purified nuclear fractions and subsequent removal of adhering nucleoproteins in a high salt medium. The fractions were examined in the electron microscope by both negative staining and thin sectioning techniques and were found to consist of nuclear envelope fragments of widely varying sizes. Nuclear pore complex constituents still could frequently be recognized. The chemical composition of the nuclear membrane fractions was determined and compared with those of microsomal fractions prepared in parallel. For total nuclei as well as for nuclear membranes and microsomes, various enzyme activities were studied. The results indicate that a similarity exists between both fractions of cytomembranes, nuclear envelope, and endoplasmic reticulum, with respect to their RNA:protein ratio and their content of polar and nonpolar lipids. Both membranous fractions had many proteins in common including some membrane-bound enzymes. Activities in Mg-ATPase and the two examined cytochrome reductases were of the same order of magnitude. The content of cytochrome b5 as well as of P-450 was markedly lower in the nuclear membranes. The nuclear membranes were found to have a higher buoyant density and to be richer in protein. The glucose-6-phosphatase and Na-K-ATPase activities in the nuclear membrane fraction were very low. In the gel electrophoresis, in addition to many common protein bands, some characteristic ones for either microsomal or nuclear membranous material were detected. Significant small amounts of DNA and RNA were found to remain closely associated with the nuclear envelope fragments. Our findings indicate that nuclear and endoplasmic reticulum membranes which are known to be in morphological continuity have, besides a far-reaching similarity, some characteristic differences.

scholarly journals Ultrastructure of mononuclear phagocytes developing in liquid bone marrow cultures. A study on peroxidatic activity

1979 ◽  
Vol 149 (1) ◽  
pp. 17-26 ◽  
Author(s):  
JWM Van Der Meer ◽  
RHJ Beelen ◽  
DM Fluitsma ◽  
R Van Furth
Keyword(s):  
Bone Marrow ◽  
Endoplasmic Reticulum ◽  
Golgi Apparatus ◽  
Nuclear Envelope ◽  
Rough Endoplasmic Reticulum ◽  
Precursor Cells ◽  
Mononuclear Phagocytes ◽  
Peroxidatic Activity

Monoblasts, promonocytes, and macrophages in in vitro cultures of murine bone marrow were studied ultrastructurally, with special attention to peroxidatic activity. Monoblasts show peroxidatic activity in the rough endoplasmic reticulum and nuclear envelope as well as in the granules. The presence of peroxidatic activity in the Golgi apparatus could not be determined. Promonocytes have peroxidase-positive rough endoplasmic reticulum, Golgi apparatus, nuclear envelope, and granules, as previously reported. During culture, cells are formed with peroxidatic activity similar to that of monocytes or exudate macrophages (positive granules; negative Golgi apparatus, RER, and nuclear envelope); we call these cells early macrophages. In addition, transitional macrophages with both positive granules and positive RER, nuclear envelope, negative Golgi apparatus (as in exudate- resident macrophages in vivo), and mature macrophages with peroxidatic activity only in the RER and nuclear envelope (as in resident macrophages in vivo) were found. A considerable number of cells without detectable peroxidatic activity were also encountered. Our finding that macrophages with the peroxidatic pattern of monocytes (early macrophages), exudate-resident macrophages (transitional macrophages), and resident macrophages (mature macrophages), develop in vitro from proliferating precursor cells deriving from the bone marrow, demonstrates once again that resident macrophages in tissues originate from precursor cells in the bone marrow. Therefore, this conclusion can no longer be challenged on the basis of a cytochemical difference between monocytes and exudate macrophages on the one hand and resident macrophages on the other.

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