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Results for “Processing Bodies”

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PubMed1999

Assembly of the nuclear transcription and processing machinery: Cajal bodies (coiled bodies) and transcriptosomes.

We have examined the distribution of RNA transcription and processing factors in the amphibian oocyte nucleus or germinal vesicle. RNA polymerase I (pol I), pol II, and pol III occur in the Cajal bodies (coiled bodies) along with various components required for transcription and processing of the three classes of nuclear transcripts: mRNA, rRNA, and pol III transcripts. Among these components are transcription factor IIF (TFIIF), TFIIS, splicing factors, the U7 small nuclear ribonucleoprotein particle, the stem-loop binding protein, SR proteins, cleavage and polyadenylation factors, small nucleolar RNAs, nucleolar proteins that are probably involved in pre-rRNA processing, and TFIIIA. Earlier studies and data presented here show that several of these components are first targeted to Cajal bodies when injected into the oocyte and only subsequently appear in the chromosomes or nucleoli, where transcription itself occurs. We suggest that pol I, pol II, and pol III transcription and processing components are preassembled in Cajal bodies before transport to the chromosomes and nucleoli. Most components of the pol II transcription and processing pathway that occur in Cajal bodies are also found in the many hundreds of B-snurposomes in the germinal vesicle. Electron microscopic images show that B-snurposomes consist primarily, if not exclusively, of 20- to 30-nm particles, which closely resemble the interchromatin granules described from sections of somatic nuclei. We suggest the name pol II transcriptosome for these particles to emphasize their content of factors involved in synthesis and processing of mRNA transcripts. We present a model in which pol I, pol II, and pol III transcriptosomes are assembled in the Cajal bodies before export to the nucleolus (pol I), to the B-snurposomes and eventually to the chromosomes (pol II), and directly to the chromosomes (pol III). The key feature of this model is the preassembly of the transcription and processing machinery into unitary particles. An analogy can be made between ribosomes and transcriptosomes, ribosomes being unitary particles involved in translation and transcriptosomes being unitary particles for transcription and processing of RNA.

Animals↗

PubMed1983

Course of antrum and body gastritis in pernicious anemia families.

The course of antrum and body gastritis was studied using an essentially linear multicompartmental model in pernicious anemia probands, their first-degree relatives, and controls consisting of a representative family sample of a large Finnish population. Our earlier dynamic approach showed that progression of body gastritis was virtually identical in a series followed up with biopsies and in cross-comparison analyses, indicating that cross-sectional data can be used for dynamic analyses at a population level. The collected data fitted a model which consisted of stepwise progression of body gastritis to severe atrophy, of corresponding progressive steps for antral gastritis, and of regression of the antral changes after the end-stage of the body process had been reached. In addition, acceleration of the progression of gastritis in older subjects had to be taken into account in the model construction. The main findings which characterized pernicious anemia probands and their close relatives were: (1) a rapid overall progression of body gastritis particularly after 50 years of age; (2) a very rapid progression of body atrophy in its final stages, which was unrelated to age; (3) the occurrence of juvenile severe body atrophy; and (4) the healing of antral gastritis which was most marked at the stage of superficial gastritis. These results may offer a dynamic explantation for the occurrence of severe body atrophy in association with a normal or slightly altered antral mucosa in pernicious anemia and the prepernicious anemia state.

Adult↗

PubMed2006

Dendritic localization of the translational repressor Pumilio 2 and its contribution to dendritic stress granules.

Pumilio (Pum) protein acts as a translational inhibitor in several organisms including yeast, Drosophila, Xenopus, and mammals. Two Pumilio genes, Pum1 and Pum2, have been identified in mammals, but their function in neurons has not been identified. In this study, we found that Pum2 mRNA is expressed during neuronal development and that the protein is found in discrete particles in both the cell body and the dendritic compartment of fully polarized neurons. This finding indicates that Pum2 is a novel candidate of dendritically localized ribonucleoparticles (RNPs). During metabolic stress, Pum2 is present in stress granules (SGs), which are subsequently detected in the somatodendritic domain. It remains excluded from processing bodies under all conditions. When overexpressed in neurons and fibroblasts, Pum2 induces the formation of SGs that also contain T-cell intracellular antigen 1 (TIA-1)-related protein, eukaryotic initiation factor 4E, poly(A)-binding protein, TIA-1, and other RNA-binding proteins including Staufen1 and Barentsz. This induction of SGs is dependent on the RNA-binding domain and a glutamine-rich region in the N terminus of Pum2. This glutamine-rich region behaves in a similar manner as TIA-1 and prion protein, two molecules with known roles in protein aggregation. Pum2 downregulation in neurons via RNA interference (RNAi) interferes with the formation of SGs during metabolic stress. Cotransfection with an RNAi-resistant portion of the Pum2 mRNA restores SG formation. These results suggest a role for Pum2 in dendritic RNPs and SG formation in mammalian neurons.

Animals↗

PubMed1986

The structure analysis of Hirano bodies by digital processing on electron micrographs.

To clarify the structure of Hirano bodies, electron micrographs of Hirano bodies taken at various tilting angles have been studied by digital image analysis. On the electron micrographs, the beaded filaments of Hirano bodies were turned into a pattern of lattice-like arrays by changing the tilting angles. Based on computer-processed diffraction patterns and filtered images, it is proposed that the filaments of Hirano bodies are helical strands with a pitch of 185 A. A model for the helical strand drawn by microcomputer at various angles of rotation is in accordance with the filtered images of the tilted filaments. Computer simulation also reveals that the helical strands appear to be lattice-like when they are arranged in parallel.

Dementia↗

PubMedDate not supplied

[Characteristics of aphakic eye in patients with diabetes].

Ninety patients with aphakia and diabetes were examined. Intraocular pressure was normal in 30 patients, in 30 aphakia was concomitant with primary glaucoma, and 30 presented with aphakic glaucoma. Fundus oculi was examined with a slit lamp and +60 D lens, gonioscopy and cycloscopy were carried out using a contact prism proposed by the authors. Aphakic glaucoma developed as a result of changes in the anterior chamber corner: coarse postoperative cicatrices and vitreo-corneal adhesions. Diabetic retinopathy was equally incident in all three groups of patients. Changes in the ciliary vessels can anticipate diabetic retinopathy. New vessels on ciliary body processes is an unfavorable prognostic sign as regards visual functions in patients with aphakia and increased intraocular pressure.

Aged↗

PubMed2003

Cysteine protease activity is required for surfactant protein B processing and lamellar body genesis.

Surfactant protein (SP)-B is essential for lamellar body genesis and for the final steps in proSP-C post-translational processing. The mature SP-B protein is derived from multistep processing of the primary translation product proSP-B; however, the enzymes required for these events are currently unknown. Recent ultrastructural colocalization studies have suggested that the cysteine protease Cathepsin H may be involved in proSP-B processing. Using models of isolated human type 2 cells in culture, we describe the effects of cysteine protease inhibition by E-64 on SP-B processing and type 2 cell differentiation. Pulse-chase labeling and Western immunoblotting studies showed that the final step of SP-B processing, specifically cleavage of SP-B(9) to SP-B(8), was significantly inhibited by E-64, resulting in delayed accumulation of SP-B(8) without adverse effects on SP-A or glyceraldehyde phosphate dehydrogenase expression. E-64 treatment during type 2 cell differentiation mimicked features of inherited SP-B deficiency in humans and mice, specifically disrupted lamellar body genesis, and aberrant processing of proSP-C. Reverse transcriptase-polymerase chain reaction and Western immunoblotting studies showed that Cathepsin H is induced during in vitro differentiation of type 2 cells and localizes with SP-B in multivesicular bodies, composite bodies, and lamellar bodies by immunoelectron microscopy. Furthermore, Cathepsin H activity was specifically inhibited in a dose-dependent fashion by E-64. Our data show that a cysteine protease is involved in SP-B processing, lamellar body genesis, and SP-C processing, and suggest that Cathepsin H is the most likely candidate protease.

Base Sequence↗

PubMed2005

MicroRNA function: multiple mechanisms for a tiny RNA?

MicroRNAs are sequence-specific regulators of post-transcriptional gene expression in many eukaryotes. They are believed to control the expression of thousands of target mRNAs, with each mRNA believed to be targeted by multiple microRNAs. Recent studies have uncovered various mechanisms by which microRNAs down-regulate their target mRNAs and have linked a well-known subcellular structure, the cytoplasmic processing bodies (PBs) to the microRNA pathway. The finding that microRNAs are misexpressed in cancers has reinforced the idea that their regulatory roles are very important.

Animals↗

PubMed2006

A comparison of physiological and behavioural parameters in C57BL/6J mice undergoing food or water restriction regimes.

Laboratory animals, when subjected to behavioural tests, are often motivationally primed by a period of prior water or food restriction. To date, it is still debatable which restriction protocol (water versus food) is more appropriate for different species. In general, a protocol is considered appropriate if animal discomfort is kept to a minimum whilst motivation for the task is maximised. Here we present a comparison study of the effects of water versus food restriction protocols in mice. The characterisation of the physiological and behavioural effects of food and water restriction in mice is beneficial for both institutional animal care centres and the scientific community. We have investigated body weight fluctuations in three groups of C57BL/6J female mice (water-restricted, food-restricted and control) in two different protocols (20 h versus 22 h of restriction per day) over 2 consecutive weeks. Subsequently, a selected number of mice from each group were subjected to a battery of behavioural tests to investigate exploratory, emotional and dominance behaviours, in addition to learning and memory processes. Body weight fluctuations suggested that mice tolerate a water restriction regimen better than a comparable food restriction regimen. Furthermore, behavioural performances demonstrated that food-restricted mice show a reduction in the exploration of a new environment and particular aspects of their timing memories are distorted. Finally, both water- and food-restricted mice tended to be more offensive than control mice when paired with an opponent in a social dominance test condition.

Adaptation, Physiological↗

PubMed1994

Acrylamide-induced distal axon degeneration: a proposed mechanism of action.

Exposure to acrylamide (ACR) monomer produces distal swelling and subsequent degeneration in central and peripheral myelinated axons of humans and laboratory animals. The molecular and cellular events leading to this type of axonopathy are currently unknown. Herein we describe a new mechanism of ACR axonopathy that represents a synthesis of recent research findings and prior hypotheses. According to this model, ion regulation in distal paranodal axon regions is compromised by diminished axolemmal Na/K-ATPase activity. It is suggested that decreased NA/K-ATPase activity is a consequence of aberrant cell body processing and/or deficient axonal transport. Reduced Na pump activity promotes membrane depolarization in conjunction with axoplasmic accumulation of Na and loss of K. Thermodynamically, this favors reverse operation of the Na/Ca-exchanger which permits axonal Ca entry in exchange for Na. The influx of Ca eventually overwhelms buffering mechanisms and leads to distal axon degeneration. Distal axons are predisposed to regulatory failure of this type due to a dependency on cell body output and the unique differential distribution of enzymes, ion channels and exchangers among nodal and internodal regions. This heuristic model might account for axon degeneration occurring as a result of exposure to other chemical neurotoxicants and following axotomy and other forms of mechanical injury.

Acrylamide↗

PubMed2004

unc-119 homolog required for normal development of the zebrafish nervous system.

The UNC-119 proteins, found in all metazoans examined, are highly conserved at both the sequence and functional levels. In the invertebrates Caenorhabditis elegans and Drosophila melanogaster, unc-119 genes are expressed pan-neurally. Loss of function of the unc-119 gene in C. elegans results in a disorganized neural architecture and paralysis. The function of UNC-119 proteins has been conserved throughout evolution, as transgenic expression of the human UNC119 gene in C. elegans unc-119 mutants restores a wild-type phenotype. However, the nature of the conserved molecular function of UNC-119 proteins is poorly understood. Although unc-119 genes are expressed throughout the nervous system of the worm and fly, the analysis of these genes in vertebrates has focused on their function in the photoreceptor cells of the retina. Here we report the characterization of an unc-119 homolog in the zebrafish. The Unc119 protein is expressed in various neural tissues in the developing zebrafish embryo and larva. Morpholino oligonucleotide (MO)-mediated knockdown of Unc119 protein results in a "curly tail down" phenotype. Examination of neural patterning demonstrates that these "curly tail down" zebrafish experience a constellation of neuronal defects similar to those seen in C. elegans unc-119 mutants: missing or misplaced cell bodies, process defasciculation, axon pathfinding errors, and aberrant axonal branching. These findings suggest that UNC-119 proteins may play an important role in the development and/or function of the vertebrate nervous system.

Amino Acid Sequence↗

PubMed2003

Cystatins.

Chicken egg white cystatin was first described in the late 1960s. Since then, our knowledge about a superfamily of similar proteins present in mammals, birds, fish, insects, plants and some protozoa has expanded, and their properties as potent peptidase inhibitors have been firmly established. Today, 12 functional chicken cystatin relatives are known in humans, but a few evolutionarily related gene products still remain to be characterized. The type 1 cystatins (A and B) are mainly intracellular, the type 2 cystatins (C, D, E/M, F, G, S, SN and SA) are extracellular, and the type 3 cystatins (L- and H-kininogens) are intravascular proteins. All true cystatins inhibit cysteine peptidases of the papain (C1) family, and some also inhibit legumain (C13) family enzymes. These peptidases play key roles in physiological processes, such as intracellular protein degradation (cathepsins B, H and L), are pivotal in the remodelling of bone (cathepsin K), and may be important in the control of antigen presentation (cathepsin S, mammalian legumain). Moreover, the activities of such peptidases are increased in pathophysiological conditions, such as cancer metastasis and inflammation. Additionally, such peptidases are essential for several pathogenic parasites and bacteria. Thus cystatins not only have capacity to regulate normal body processes and perhaps cause disease when down-regulated, but may also participate in the defence against microbial infections. In this chapter, we have aimed to summarize our present knowledge about the human cystatins.

Cystatins↗

PubMed1999

Origin of graphitic carbon and pentlandite in matrix olivines in the Allende meteorite.

Matrix olivines in the Allende carbonaceous chondrite are believed to have formed by condensation processes in the primitive solar nebula. However, transmission electron microscope observations of numerous matrix olivines show that they contain abundant, previously unrecognized, nanometer-sized inclusions of pentlandite and poorly graphitized carbon. Neither of these phases would have been stable at the high-temperature conditions required to condense iron-rich olivine in the solar nebula. The presence of these inclusions is consistent with formation of the olivines by parent body processes that involved overgrowth of fine-grained organic materials and sulfides in the precursor matrix materials.

Alloys↗

PubMed1999

[Neuropathology of amyotrophic lateral sclerosis--from basic findings to topics].

Amyotrophic lateral sclerosis (ALS) is a relentlessly progressive neurodegenerative disease that selectively affects upper and low motor neurons (UMNs and LMNs). The remaining LMNs show, in addition to normal appearance, a variety of cell pathology such as central chromatolysis, atrophy of the cell body and processes, Bunina bodies, and ubiquitinated hyaline and skein-like inclusions. Ultrastructural studies of the last two profiles indicate their processing by lysosomes. Whether apoptosis is responsible for motoneuronal death in ALS or not remains to be determined. In Klüver-Barrera (KB) staining, the pyramidal tracts in ALS usually appear normal at the pons in spite of their obvious pallor at the lower levels, leading to the dying-back hypothesis. However, axonal staining in such cases reveals obvious loss of large axons in the pontine pyramidal tracts, a finding inconsistent with the hypothesis. Similarly, in cases of motoneuron disease with the pyramidal tracts well stained by KB method, therefore, 'spinal progressive muscular atrophy (SPMA)', axonal staining demonstrated patent loss of large axons there. Thus, reappraisal seems to be required for previously reported SPMA cases, whose pathological diagnosis used to be made by KB staining alone.

Amyotrophic Lateral Sclerosis↗

PubMed2005

Wearable healthcare systems, new frontiers of e-textile.

There is a growing need of renovation in our health care managing systems; people need to be more interactive and more conscious of their own health condition in a way to adjust incorrect lifestyles, to obtain a personalized therapy tuned to their own physiological reactions and on their own environmental condition. To gain knowledge of a citizen's health status and to monitor without harassing them (until they refuse any medical supervision), a comfortable remote monitoring of important physiological parameters is necessary. The approach is therefore to integrate system solutions into functional clothes with integrated textile sensors. The combination of functional clothes and integrated electronics and on-body processing, is defined as e-textile and gives rise to intelligent biomedical clothes. Systems, designed to be minimally invasive, are based on smart textile technologies, where conductive and piezoresistive materials in the form of fiber and yarn are used to realize clothes, in which knitted fabric sensors and electrodes are distributed and connected to an electronic portable unit. These systems are able to detect, acquire and transmit physiological signals. They are conformable to the human body, and move towards improving the patient's quality of life and their autonomy. These systems are also cost-effective in providing around-the-clock assistance, in helping physicians to monitor for example cardiac patients during periods of rehabilitation, and in addition result in decreased hospitalization time. Finally, by providing direct feedback to the users, they improve their awareness and potentially allow better control of their own condition, while the simultaneous recording of vital signs permits parameter extrapolation and inter-signal elaboration that contributes to produce alert messages and personalized synoptic tables of the patient's health.

Biomedical Technology↗

PubMed1991

[Pars plana capsule resection for therapy of ocular hypotension syndrome caused by capsule shrinkage with ciliary body detachment].

A rare complication of extracapsular cataract extraction is hypotony due to capsular shrinkage, with consequent ciliary body detachment. A classic hypotony syndrome with progressive loss of visual acuity was observed in two patients, one with extracapsular aphakia and one with extracapsular pseudophakia. Each presented with a fibrotic, shrunken capsular bag and a secondary cataract. As the contraction forces appeared to derive predominantly from the periphery of a circumferentially fibrotic capsular bag, the lens capsule was operatively removed. A pars plana approach was used to access the equatorial capsular ring and visualize the ciliary body processes. The intraocular lens appeared to be stable and remained in situ. Postoperative elevation of intraocular pressure occurred, with improvement of hypotony symptoms, especially in the fundus. Visual acuity also improved, but was limited due to secondary cystoid edema.

Adult↗

PubMed1991

Comparison of lectin reactivity in the vessel beds of the rat eye.

The capillary beds of the eye are lined by two types of endothelia, fenestrated in the choriocapillaris and ciliary body, and continuous in the retina and iris. In this study, we wished to find a marker for each of these types of vessel beds using lectin histochemistry. Sections of glutaraldehyde fixed rat eyes embedded in epoxy resin were extracted with sodium ethoxide and rehydrated. Binding of 15 different lectins was visualized using the avidin-biotin peroxidase technique. We found WGA, WGA-s, LFA and PHA-E to strongly bind retinal vessels. In addition to the above lectins, iris vessels bound GSL-I. Choriocapillaris reacted variably only with WGA and not at all with other lectins tested. Vessels of ciliary body processes did not react with any lectin studied. The less fenestrated vessels of the base of the ciliary process bound lectins similar to the retina. We speculate that the differential lectin staining of the various vessel beds of the eye may reflect the degree of fenestration of the endothelium. This reactivity may be influenced by variations in the surrounding milieu including cells and extracellular matrix.

Animals↗

PubMed2001

Cooperative processes governing formation of small pentanuclear lanthanide(III) nanoclusters and energy transport within and between them.

Syntheses, lanthanide quantitative analyses, mass spectrometry and luminescence spectroscopy, and decay dynamics of crystals containing pentanuclear hetero-lanthanide(III) nanoclusters [(Ln'(5-x)Ln(x))(NO(3))(6)(mu(5)-OH)(mu(4)-L)(2)] (0 < or = x < or = 5), Ln' = Eu or Tb; Ln = La-Nd, Sm-Ho (hereafter Ln'(5-x) Ln(x)) were undertaken in search of information on factors governing self-assembly processes by which the clusters are formed and electronic interactions within and between them. The data obtained are consistent with the self-assembly of Ln'(5-x) Ln(x) nanoclusters being a concerted process featuring a profound expression of complementarity among mutually bridging [Ln(mu(4)-L](-) and [Ln(NO(3))(2)](+) components. The energy transport regime in crystals of Eu(5-x) Ln(x) is in the dynamic regime when x = 0 or Ln = La and, at 293 K, Ln = Dy, despite the presence of two crystallographically different Eu(3+) coordination environments which give rise to a doublet in the excitation and emission spectra of Eu(3+)((5)D(0)). The luminescence decay behavior of Eu(3+)((5)D(0)) in Eu(5-x) Ln(x) (Ln = Dy (for 77 K), Sm) is intermediate between the static and dynamic limits and reveals extensive electronic coupling among lanthanide ions, including many-body processes at relatively high Dy(3+) or Sm(3+) concentrations.

Journal Article↗

PubMed1997

Dietary fat and human obesity.

When energy is in excess, the human body processes nutrients according to an oxidative hierarchy. Excessive carbohydrate and protein intakes are disposed of by increased oxidation. In contrast, excess fat intake does not promote its own oxidation in the short- and mid-term. This leads, in the long-term, to an increase in fat stores. Although increased adiposity represents the common response to increased fat intake, there are interindividual differences in lipid oxidation (probably genetically determined) that may protect from or predispose to obesity.

Body Constitution↗