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Results for “Intranuclear Space”

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PubMed1994

Systemic osmotic stimulation increases vasopressin and oxytocin release within the supraoptic nucleus.

Vasopressin (VP) and oxytocin (OT) are released within the hypothalamic nuclear region in response to direct microdialysis with hypertonic solutions. Experiments were performed to determine whether systemic osmotic stimulation causes changes in intranuclear peptide release within the supraoptic nucleus (SON). A hypertonic sodium chloride solution was injected intraperitoneally (i.p.) or intravenously (i.v.) and microdialysis techniques were used to simultaneously monitor central and peripheral peptide release in urethane anesthetized rats. Systemic osmotic stimuli elicited increases in intranuclear peptide release which were delayed and long-lasting, occurring over a 2.5 h period. In contrast, plasma peptide levels peaked at 30-min after the stimulus. The results demonstrate that increased plasma sodium elicits an increase in VP and OT release into the extracellular space of the hypothalamic SON. The different patterns of peptide release in plasma and brain point toward the possibility of independently regulated release into the different compartments.

Animals↗

PubMed2006

[Development of non-viral vector based on the quantitative comparison of intracellular trafficking with viral vector].

For the development of efficient gene vector, intracellular processes such as cellular uptake, endosomal release and nuclear delivery must be overcome. Viruses have also evolved and have developed sophisticated mechanisms for controlling intracellular trafficking for the efficient delivery of their genomes to nuclei in host cells for symbiosis. In the light of these mechanisms, various kinds of artificial devices have been developed to overcome the intracellular barriers. However, in the majority of studies, variation of the transfection activity before and after the modification of devices was evaluated, and intracellular trafficking remained unclear. Therefore, it is understand to recognize which of the intracellular barrier should be intensively improved to enhance the transfection activity. To clarify the rate-limited process in the current non-viral vector, we compared the intracellular trafficking between adenovirus and LipofectAMINE PLUS. As a result, we found that difference of the transfection efficiency between adenovirus and LipofectAMINE PLUS was dominantly derived from the differences on transcription activity. Therefore it is essential to consider the regulation of the intranuclear events to improve the transfection activity of artificial vector.

Active Transport, Cell Nucleus↗

PubMed2006

Search for the invisible decay of neutrons with KamLAND.

The Kamioka Liquid scintillator Anti-Neutrino Detector is used in a search for single neutron or two-neutron intranuclear disappearance that would produce holes in the -shell energy level of (12)C nuclei. Such holes could be created as a result of nucleon decay into invisible modes (inv), e.g., n--> 3v or nn--> 2v. The deexcitation of the corresponding daughter nucleus results in a sequence of space and time-correlated events observable in the liquid scintillator detector. We report on new limits for one- and two-neutron disappearance: tau(n--> inv) > 5.8 x 10(29) years and tau (nn--> inv) > 1.4 x 10(30) years at 90% C.L. These results represent an improvement of factors of approximately 3 and >10(4) and over previous experiments.

Journal Article↗

PubMed1998

Altered expression and localization of 5-lipoxygenase accompany macrophage differentiation in the lung.

The alveolar macrophage (AM) exhibits a greater capacity to synthesize bioactive leukotrienes from arachidonic acid than does its circulating precursor the peripheral blood monocyte. Macrophage differentiation in the lung entails cellular residence within both the pulmonary interstitial and alveolar compartments. In the present study, we sought to determine 1) whether this enhanced metabolic activity was acquired during maturation within the alveolar space and 2) the underlying mechanisms responsible for this upregulation. Rat AMs were separated by Percoll gradient centrifugation into four density-defined subpopulations thought to reflect their degree of maturation. On stimulation with a calcium ionophore, synthesis of leukotriene B4 increased with the degree of maturation, although it was diminished in the oldest subpopulation. This maturation-dependent upregulation was not explained by increases in arachidonic acid release but was associated with increased expression of 5-lipoxygenase (5-LO) protein as determined by immunoblot analysis. Whereas 5-LO is primarily cytosolic in monocytes, it is known to be primarily intranuclear in unfractionated AMs. Here, the localization of 5-LO was investigated by immunofluorescence microscopy and was found to be predominantly nuclear in all AM subpopulations; by contrast, the protein was cytosolic in interstitial macrophages isolated by mechanical and enzymatic lung digestion. These divergent localization patterns in AMs and interstitial macrophages were verified in situ by immunohistochemical staining of sections of normal rat lung. When unfractionated AMs were isolated and maintained in culture for 3 days, a shift in 5-LO distribution from nucleus to cytosol was observed. We conclude that 1) nuclear import of 5-LO occurs within the alveolar space and is reversible on removal from the alveolar milieu and 2) leukotriene synthetic capacity increases further during AM residence within the alveolar space as a result of a progressive increase in the amount of 5-LO protein.

Animals↗

PubMed1999

Movement of nuclear poly(A) RNA throughout the interchromatin space in living cells.

BACKGROUND: Messenger RNA (mRNA) is transcribed and processed in the nucleus of eucaryotic cells and then exported to the cytoplasm through nuclear pores. It is not known whether the movement of mRNA from its site of synthesis to the nuclear pore is directed or random. Directed movement would suggest that there is an energy-requiring step in addition to the step required for active transport through the pore, whereas random movement would indicate that mRNAs can make their way to the nuclear envelope by diffusion. RESULTS: We devised a method to visualize movement of endogenous polymerase II transcripts in the nuclei of living cells. Oligo(dT) labeled with chemically masked (caged) fluorescein was allowed to penetrate cells and hybridize to nuclear poly(A) RNA. Laser spot photolysis then uncaged the oligo(dT) at a given intranuclear site and the resultant fluorescent, hybridized oligo(dT) was tracked using high-speed imaging microscopy. Poly(A) RNA moved away from the uncaging spot in all directions with a mean square displacement that varied linearly with time, and the same apparent diffusion coefficient was measured for the movement at both 37 degrees C and 23 degrees C. These properties are characteristic of a random diffusive process. High resolution three-dimensional imaging of live cells containing both Hoechst-labeled chromosomes and uncaged oligo(dT) showed that, excluding nucleoli, the poly(A) RNA could access most, if not all, of the non-chromosomal space in the nucleus. CONCLUSIONS: Poly(A) RNA can move freely throughout the interchromatin space of the nucleus with properties characteristic of diffusion.

Animals↗

PubMed1972

Development of an equine herpesvirus in two cell culture systems: light and electron microscopy.

Development of equine herpesvirus strain 82A was studied in cells from primary horse kidney (HOK) cultures and an equine dermis (ED) cell strain. HOK and ED cells are equally susceptible to the 82A virus infection and yield about the same amount of infectious virus. Intranuclear inclusions were present in both cell systems, but a ring-shaped syncytial formation was observed only in infected ED cells. Ultrastructural studies revealed the presence of dense granules 30 nm in diameter and characteristic star-like clusters of granules in the infected HOK cells, but these granules were rarely seen in the infected ED cells. Viral nucleocapsids were associated with homogenous nuclear matrices, with moderate electron density in both cell systems. Viral nucleocapsids acquired envelopes by budding into the nuclear vacuoles in both HOK and ED cells. Budding from inner nuclear membranes into perinuclear cisterna or into cytoplasmic vacuoles also was observed frequently in HOK cells but was not seen often in infected ED cells. Multiple, membrane-bound intranuclear inclusions of fibrillar material which may be associated with virus envelopes were seen only in infected ED cells. Enveloped virus particles seen in nuclear vacuoles or perinuclear cisterna were more regular in shape and had a 130-nm diameter, whereas the enveloped virus particles seen in the cytoplasm and extracellular space were more irregular in shape and had a 130- to 160-nm diameter.

Animals↗

PubMedDate not supplied

Heat-induced damage to HeLa-S3 cells: correlation of viability, permeability, osmosensitivity, phase-contrast light-, scanning electron- and transmission electron-microscopical findings.

The responses of HeLa S-3 to mild hyperthermia for relatively critical times at 43 and 45 degrees C were analysed in detail, including growth and colony-forming ability, permeability, osmotic sensitivity and microscopical appearances. For comparative purposes lower temperatures (e.g. 41 degrees C) and higher temperatures (50 and 55 degrees C) were used in some experiments. The evidence from many different aspects, including scanning and transmission electron microscopy, suggests that critical heat exposures do not per se cause severe membrane damage and loss of cell integrity, but changes quickly become manifest when cells are 'recovered' by returning to 37 degrees C. Attention is drawn to the ability of heat-treated cells to show osmotic-like swelling and restoration towards normal volume in medium of 30 per cent normal strength, which would not be expected on the hypothesis that hyperthermia primarily disrupts membrane structure and functioning. Ultrastructural changes during and after hyperthermia--including nucleolar changes, the appearance of perichromatin granules, the formation of electron-dense cytoplasmic clusters, and the development of intranuclear actin rods--corroborate and extend other findings. However, mitochondrial changes were found to be particularly significant, appearing early and correlating well with the loss of viability and metabolic functioning found after heat treatment. These include the early development of intramitochondrial dense granules, followed by vesicularization of the cristae, swelling of the intracristal spaces, myelin degeneration and the formation of bodies which could otherwise be mistaken for secondary lysosomes. The findings indicate the need for more intensive investigations of mitochondria and mitochondrial functioning in hyperthermia-induced cell damage, and their careful correlation with the 'recovery' of energy-dependent process in cells subsequently returned to 37 degrees C.

Cell Division↗

PubMed2004

Actin- and protein-4.1-containing filaments link nuclear pore complexes to subnuclear organelles in Xenopus oocyte nuclei.

We imaged the interiors of relatively intact Xenopus oocyte nuclei by field emission scanning electron microscopy (feSEM) and visualized a network of filaments that attach to nuclear pore complexes and extend throughout the nucleus. Within the nucleus, these 'pore-linked filaments' (PLFs) were embedded into spherical structures 100 nm to approximately 5 microm in diameter. A subset of spheres was identified as Cajal bodies by immuno-gold labeling; the rest were inferred to be nucleoli and snurposomes both of which are abundant in Xenopus oocyte nuclei. Most PLFs were independent of chromatin. The thickness of a typical PLF was 40 nm (range, approximately 12-100 nm), including the 4 nm chromium coat. PLFs located inside the nucleus merged, bundled and forked, suggesting architectural adaptability. The PLF network collapsed upon treatment with latrunculin A, which depolymerizes actin filaments. Jasplakinolide, which stabilizes actin filaments, produced PLFs with more open substructure including individual filaments with evenly-spaced rows of radially projecting short filaments. Immuno-gold labeling of untreated oocyte nuclei showed that actin and protein 4.1 each localized on PLFs. Protein 4.1-gold epitopes were spaced at approximately 120 nm intervals along filaments, and were often paired ( approximately 70 nm apart) at filament junctions. We suggest that protein 4.1 and actin contribute to the structure of a network of heterogeneous filaments that link nuclear pore complexes to subnuclear organelles, and discuss possible functions for PLFs in nuclear assembly and intranuclear traffic.

Actins↗

PubMed2006

Intracellular amyloid beta-protein and its associated molecules in the pathogenesis of Alzheimer's disease.

Amyloid beta-protein (Abeta) plays a pivotal role in Alzheimer's disease (AD). Therapeutic strategies inhibiting Abeta aggregation and promoting extracellular Abeta removal are currently advocated. Here, we review recent literature on intracellular Abeta, especially intranuclear Abeta, and its associated molecules. We also discuss alternative therapeutic strategies to inhibit intracellular Abeta-related pathogenesis.

Alzheimer Disease↗

PubMed1981

[Histologic and electron microscopical investigations in a patient with benign verrucosis generalisata (author's transl)].

A report is given on a 43-year-old man who has been suffering from pointed condylomata in the region of scrotum and anus since 1975. Repeated relapses. Since 1977 verrucous lesions spreading from thorax to both arms and the throat. Histologic examination revealed intraepidermal foci of balloon cells in the stratum spinosum and stratum granulosum, partly with intranuclear basophilic inclusions. Electron microscopy showed an intact basal lamina and also partly intact epidermis. Only in the focal area the epidermopoiesis is disturbed already from the basal layer, with vacuolated destruction of the basal keratinocytes and condensation of the cytoplasm, as well as formation of myelin figures. This degenerative process together with enlarged intercellular spaces and partly conserved desmosomes continues into the stratum granulosum. From the upper stratum spinosum balloon cells characteristic for warts are found. In the stratum granulosum there are abundant atypic keratohyalin granules, and in the stratum granulosum and stratum corneum characteristic virus-containing kerationcytes are found. Furthermore, there are lots of released virus elementary bodies deposited in bizarre shapes at the horny lamellae: crystalloid or garland-, chain-, letter-, or wreath-shaped.

Humans↗

PubMedDate not supplied

[Late stages in the replicative cycle of human cytomegaloviruses in diploid cells. Ultrastructural study].

An ultrastructural study of late stages of the replicative cycle of human cytomegalovirus (CMV) in human embryo fibroblasts cell cultures has been performed. Nucleocapsids are observed only inside the intranuclear inclusion. They mature apparently by taking the envelope from the structural components of microvescicular systems reaching from the nuclear membrane the periphery of the nuclear inclusion. However, some capsids reach "naked" the cytoplasm and then take the envelope from cytoplasmic membranes. In the cytoplasm homogeneous "dense material" and "dense microbodies" are present; in extracellular space enveloped "dense microbodies" are scattered among virions. The peculiar envelopment of CMV capsids, not yet described in the literature, is discussed and the typical ultrastructural cytopathology of CMV infected cells is indicated as an useful tool in diagnostic virology.

Cell Membrane↗

PubMed2004

Sperm structure and spermiogenesis in Coletinia sp. (Nicoletiidae, Zygentoma, Insecta) with a comparative analysis of sperm structure in Zygentoma.

The spermatozoon of Coletinia sp. has a bilayered acrosome, a short nucleus (4 microm) and a relatively short sperm tail with two mitochondrial derivatives. The chromatin is uniformly dense except for several electron-lucid channels or strands which permeate the nucleus and which originate in the spermatid as invaginations of the nuclear envelope. The invaginations occur mostly or exclusively along two meridians of the spermatid that are also characterized by the presence of a longitudinal rod of medium electron density. The two rods (designated as 'mid-spermatid rods') evidently are instrumental in the formation of the electron-lucid channels. The significance of this elaborate system of intranuclear channels is not understood. The sperm tail has a 9 + 9 + 2 axoneme with each of the nine microtubular doublets accompanied by an accessory microtubule; scant intertubular material can also be distinguished. Hence, the tail axoneme resembles that of many pterygote insects. Each of the two mitochondrial derivatives contains a crystalline inclusion that has periodically spaced layers going in different directions on either side of the midline. Two synapomorphic traits appear to be shared by Ateluridae and Nicoletiidae, namely the invaginations of the nuclear membrane along two meridians of the nucleus and the shape of the crystalline inclusions of the mitochondrial derivatives. Four species from the family Lepismatidae were also examined as to their sperm ultrastructure. Three of them, Allacrotelsa kraepelini, Ctenolepisma longicaudata and Ctenolepisma sp., were found to be very similar to the two previously examined lepismatids, Thermobia domestica and Lepisma saccharina. On the other hand, spermatozoa of Tricholepisma aurea were aggregated in small groups rather than pairwise joined as seen in the other lepismatids. Sperm characters are also used to reconstruct a phylogenetic hypothesis which suggests a close relationship between Ateluridae and Nicoletiidae.

Animals↗

PubMed2005

Characterization of a nuclear compartment shared by nuclear bodies applying ectopic protein expression and correlative light and electron microscopy.

To investigate the accessibility of interphase nuclei for nuclear body-sized particles, we analyzed in cultured cells from human origin by correlative fluorescence and electron microscopy (EM) the bundle-formation of Xenopus-vimentin targeted to the nucleus via a nuclear localization signal (NLS). Moreover, we investigated the spatial relationship of speckles, Cajal bodies, and crystalline particles formed by Mx1 fused to yellow fluorescent protein (YFP), with respect to these bundle arrays. At 37 degrees C, the nucleus-targeted, temperature-sensitive Xenopus vimentin was deposited in focal accumulations. Upon shift to 28 degrees C, polymerization was induced and filament arrays became visible. Within 2 h after temperature shift, arrays were found to be composed of filaments loosely embedded in the nucleoplasm. The filaments were restricted to limited areas of the nucleus between focal accumulations. Upon incubation at 28 degrees C for several hours, NLS vimentin filaments formed bundles looping throughout the nuclei. Speckles and Cajal bodies frequently localized in direct neighborhood to vimentin bundles. Similarly, small crystalline particles formed by YFP-tagged Mx1 also located next to vimentin bundles. Taking into account that nuclear targeted vimentin locates in the interchromosomal domain (ICD), we conclude that nuclear body-sized particles share a common nuclear space which is controlled by higher order chromatin organization.

Animals↗

PubMed1981

Electron microscopy of rabbit embryo fibroblasts infected with herpesvirus isolates from Clethrionomys glareolus and Apodemus flavicollis.

Electron microscopy of rabbit embryo fibroblasts infected with five herpesvirus isolates from murine rodents (Clethrionomys glareolus and Apodemus flavicollis) revealed morphological changes characterized by the formation of intranuclear vacuoles, in which envelopment of nucleocapsids took place. The herpesvirus nucleocapsids were formed in the vicinity of intranuclear granular inclusions. Margination of chromatin, disaggregation of nucleoli and, in some isolates, the occurrence of tubular structures with a diameter of 33--35 nm characterized the ultrastructural changes in the nuclei. In the cytoplasm, membraneous vacuoles, containing numerous naked nucleocapsids and, in some isolates, large electron-dense bodies, containing non-enveloped nucleocapsids, were formed. Extracellular spaces contained either enveloped virions which, besides nucleocapsids, contained in their envelope a part of the dense material from intracytoplasmic dense bodies, or viral envelope-like structures without nucleocapsids partially filled with dense material from intracytoplasmic dense bodies. Ultrastructural development of these isolates in REF resembled that of freshly isolated herpes simplex type 1 viruses but some morphological changes resembled those characteristic of cytomegaloviruses.

Animals↗

PubMed1978

[Electron microscopic studies of Reinke oedema (author's transl)].

With the electron microscope, changes in the epithelium and subepithelial tissue in Reinke's oedema are more clear. An intense widening of the intercellular spaces is observed, with the presence of a strongly electron dense substance. In some cells, especially in the cells of the stratum spinosum and in the endothelial cells of the capillary vessels, intracytoplasmic cystic formations are observed, which in some cases are located in nuclear invaginations. However, these cystic formations can give a false impression that they are intranuclear if an incorrect tissue section is made.

Endothelium↗

PubMed1982

Sequential development of the liver lesions in new-born lambs infected with Rift Valley fever virus. II. Ultrastructural findings.

The macroscopic and microscopic lesions in livers of new-born lambs experimentally infected with Rift Valley fever virus and killed at various intervals between 6-53 h after inoculation, were described in a previous paper. This communication gives an overview of the ultrastructural changes affecting hepatocytes, sinusoids and spaces of Disse, biliary tree and portal triads as well as observations on the morphology and morphogenesis of the virus. Hepatocytes were those primarily affected, while inflammatory and architectural changes were secondary. The changes included prominent nuclear alterations, fragmentation or disintegration of necrotic hepatocytes, focal cytoplasmic degradation and sequestration, and the presence of acidophilic bodies. The ultrastructure and origin of the intranuclear inclusions are discussed.

Animals↗

PubMed1986

Primary gastric lymphoma with intranuclear inclusions. An immunohistochemical and ultrastructural study.

Two patients with primary gastric lymphoma, diffuse lymphoma, a plasmacytoid variant of small cell type, with numerous intranuclear inclusions, are reported. In both cases, biopsy and surgical specimens showed diffuse proliferation of lymphoid cells having plasmacytoid features at different steps of maturation in lamina propria and submucosal layer. The cytoplasm of the lymphoma cells was stained with anti-IgM, anti-kappa chain, and anti-J chain antibodies by avidin-biotin peroxidase complex technique. A number of intranuclear inclusions in the lymphoma cells were diastase-resistant PAS positive, and also stained with anti-IgM, anti-kappa chain, and anti-J chain antibodies, suggesting a monoclonal situation. In an ultrastructural study of the first case, the inclusions were round and composed of amorphous materials surrounded by a single membrane. In many lymphoma cells, the perinuclear cisternal space was dilated and filled with materials similar to those within both inclusions and rough endoplasmic reticulum. A direct communication between the perinuclear space and the inclusion was demonstrated in some cells, suggesting the perinuclear cisternal origin of these inclusions.

Adult↗

PubMed2001

[Current views on function and regulation of Ca2+ levels in cell nuclei].

Ca2+ is involved in the regulation of many events in the nucleus, such as gene expression, DNA replication, DNA repair, chromatin fragmentation in apoptosis, modulation of an intranuclear contractile system. In some cases, the function of Ca2+ is mediated by calmodulin. However, the regulation of nucleoplasmic Ca2+ concentration has not been explored thoroughly. The data discussed in this review show that the [Ca2+]n may be regulated independently of that of cytosolic Ca2+. IP3 and cyclic ADP-ribose are the major factors responsible for Ca2+ release into the nucleus from perinuclear space.

Animals↗