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PubMed1984

[Studies on pathogenesis of muscular dystrophy: levels of thiobarbituric acid-reactive products in avian muscular dystrophy].

Lipid peroxidation and other free radical reactions are known to disrupt and damage cellular structures and function, and it has been postulated as possible mechanisms of cellular damage of muscular dystrophy because increased levels of thiobarbituric acid (TBA)-reactive products and increased activities of superoxide dismutase and glutathione peroxidase were reported in avian muscular dystrophy. We reported that activities of superoxide dismutase, catalase, glutathione peroxidase and glutathione reductase were significantly increased in avian muscular dystrophy from the early developmental stage. Since these enzymes protect cellular structures from free radicals and peroxides, increased activities of these enzymes would indicate increased formation of radicals. Then it seems to be important to assay TBA-reactive products which indicate tissue malondialdehyde content, a by-product of lipid peroxidation. We used dystrophic chickens of New Hampshire series line 413 and their controls line 412 for assay of TBA-reactive products. Four or five birds from respective lines were killed by decapitation two weeks, four weeks and four months after hatching. The superficial pectoral muscle was immediately weighed and levels of TBA-reactive products in the muscle homogenate was assayed by fluorophotometry according to the modified method of Ohkawa and Tanizawa. Levels of TBA-reactive products were significantly higher in dystrophic chickens at all stages of development studied than those of the control group. At two weeks of age morphological changes are minimum if present and increased levels of TBA-reactive products cannot be considered as a secondary change of morphological alterations. Therefore, the results indicate involvement of lipid peroxidation damage in pathogenesis of this avian muscular dystrophy.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2006

The depletion attraction: an underappreciated force driving cellular organization.

Cellular structures are shaped by hydrogen and ionic bonds, plus van der Waals and hydrophobic forces. In cells crowded with macromolecules, a little-known and distinct force-the "depletion attraction"-also acts. We review evidence that this force assists in the assembly of a wide range of cellular structures, ranging from the cytoskeleton to chromatin loops and whole chromosomes.

Actins↗
PubMed1996

Structure and cellular distribution of mouse brain testican. Association with the postsynaptic area of hippocampus pyramidal cells.

The complete deduced primary structure of mouse brain testican has been established from cDNA cloning. The cDNA encodes a polypeptide of 442 amino acids belonging to the proteoglycan family. The mouse brain testican core protein is 95% identical to its human testicular counterpart. In situ hybridization investigations revealed that mouse testican mRNA is mainly present in a subpopulation of pyramidal neurons localized in the CA3 area of the hippocampus. An immunocytochemical approach, with antibodies directed against an overexpressed chimeric antigen, produced in bacterial systems, showed that testican is associated with the postsynaptic region of these pyramidal neurons. Testican includes several putative functional domains related to extracellular or pericellular proteins associated with binding and/or regulatory functions. On the basis of its structural organization and its occurrence in postsynaptic areas, this proteoglycan might contribute to various neuronal mechanisms in the central nervous system.

Amino Acid Sequence↗
PubMed2004

Morphological and physiological changes induced by high hydrostatic pressure in exponential- and stationary-phase cells of Escherichia coli: relationship with cell death.

The relationship between a loss of viability and several morphological and physiological changes was examined with Escherichia coli strain J1 subjected to high-pressure treatment. The pressure resistance of stationary-phase cells was much higher than that of exponential-phase cells, but in both types of cell, aggregation of cytoplasmic proteins and condensation of the nucleoid occurred after treatment at 200 MPa for 8 min. Although gross changes were detected in these cellular structures, they were not related to cell death, at least for stationary-phase cells. In addition to these events, exponential-phase cells showed changes in their cell envelopes that were not seen for stationary-phase cells, namely physical perturbations of the cell envelope structure, a loss of osmotic responsiveness, and a loss of protein and RNA to the extracellular medium. Based on these observations, we propose that exponential-phase cells are inactivated under high pressure by irreversible damage to the cell membrane. In contrast, stationary-phase cells have a cytoplasmic membrane that is robust enough to withstand pressurization up to very intense treatments. The retention of an intact membrane appears to allow the stationary-phase cell to repair gross changes in other cellular structures and to remain viable at pressures that are lethal to exponential-phase cells.

Bacterial Proteins↗
PubMed2006

Compartmentalisation and localisation of the translation initiation factor (eIF) 4F complex in normally growing fibroblasts.

Previous observations of association of mRNAs and ribosomes with subcellular structures highlight the importance of localised translation. However, little is known regarding associations between eukaryotic translation initiation factors and cellular structures within the cytoplasm of normally growing cells. We have used detergent-based cellular fractionation coupled with immunofluorescence microscopy to investigate the subcellular localisation in NIH3T3 fibroblasts of the initiation factors involved in recruitment of mRNA for translation, focussing on eIF4E, the mRNA cap-binding protein, the scaffold protein eIF4GI and poly(A) binding protein (PABP). We find that these proteins exist mainly in a soluble cytosolic pool, with only a subfraction tightly associated with cellular structures. However, this "associated" fraction was enriched in active "eIF4F" complexes (eIF4E.eIF4G.eIF4A.PABP). Immunofluorescence analysis reveals both a diffuse and a perinuclear distribution of eIF4G, with the perinuclear staining pattern similar to that of the endoplasmic reticulum. eIF4E also shows both a diffuse staining pattern and a tighter perinuclear stain, partly coincident with vimentin intermediate filaments. All three proteins localise to the lamellipodia of migrating cells in close proximity to ribosomes, microtubules, microfilaments and focal adhesions, with eIF4G and eIF4E at the periphery showing a similar staining pattern to the focal adhesion protein vinculin.

Actins↗
PubMedDate not supplied

[Highest level of division in the organism classification. 1. Prokaryotes and eukaryotes].

The works on the general classification of all organisms are considered as a convenient opportunity to sum up numerous data obtained in organic world studying. The present stage is characterized by rapid development of the molecular reconstructions that have already caused considerable changes in our classification practice. These changes look especially impressive at studying the organism cellular structure. The great massive of new data allow us to compare Prokaryotes and Eukaryotes on the nucleic acids and especially proteins whose number in Eukaryote cell approaches to several thousands. Basing on the structure of macromolecules one can hypothesize with great certainty about Prokaryote or Eukaryotes origin. The article presents the detailed characteristic of Prokaryotes or Eukaryotes with the emphasis placed on the comparative analysis of biological macromolecules. Among specially considered cellular structures and processes are cell wall, intracellular components, cellular cycle, nucleus, DNA compactness, replication, genome organization, transcription, posttranscriptional modifications, introns, ribosomes and translation, cytoskeleton, mitosis, cytokinesis, cellular organelles, intracellular membranes systems, modes of nutrition, sexual condition. The macromolecular analysis let to carry out the homology of structures and to find out some new connections. It was shown that typology considered as a search for morphological patterns within the biodiversity structure has almost exhausted the subject. It was directed mostly to distinguishing "main" group in contrast with intermediate and aberrant ones, which were considered as minor phenomenon. At present due to macromolecules systematics it is able to estimate the whole diversity of forms including typologically transitive.

Biodiversity↗
PubMed1977

[Topography and cytoarchitectonics of the main cortical zones of the turtle forebrain].

The description of cytoarchitectonics and topography of the three principle cortical zones of the forebrain of Emys orbicularis reveals that the cortical structures in the species are precisely distinguished with respect to their neuronal characteristics, density and the situation of cellular elements. Emys orbicularis occupies an intermediate position among the species of the order Chelonia described in the literature as regards the level of development of the forebrain cellular structures. Emys orbicularis is less progressive in respect to the structure of telencephalic cortical formations than Testudo carolina and has a number of progressive properties as compared with Testudo geometrica. Testudo graeca seems to be close to Emys orbicularis in the development of forebrain cellular structures.

Animals↗
PubMed1959

Fine structure of cellular inclusions in measles virus infections.

Cells which are infected with measles virus have been known for some time to contain inclusion material that is distinguishable from normal cellular components by application of traditional staining methods and observation in the light microscope. The fine structure of the inclusion material contained in HeLa cells infected with Edmonston strain of measles virus has been examined in the electron microscope. Two steps have been found necessary in this study: (1) the recognition by phase-contrast microscopy of the living cell of bodies that are defined as inclusion material when the cells are classically stained; and (2) the recognition in the electron microscope of inclusion-body material that had previously been identified in the living cell. The fine structure of the nuclear and cytoplasmic inclusion material in osmium-treated cells was found to consist mainly of randomly arrayed filaments of low electron density. Dense, highly ordered arrays of filaments were found near the center of the nuclear inclusions, sometimes as a two-dimensional, nearly orthogonal arrangement. If the size of the measles virus is taken to be around 100 mmicro in diameter, the strands seen in the inclusions cannot be fully formed virus.

HeLa Cells↗
PubMed1993

Ultrastructural observations of hoof horn from dairy cows: changes in the white line during the first lactation.

Slivers of hoof horn were taken from the outer claw of the right hindfoot of 16 first calving dairy heifers one month before calving and one, 10 and 20 weeks after calving. The gross appearance of all four feet, and the presence and degree of solar haemorrhage were recorded. Ultra-thin sections of the white line were examined in the transmission electron microscope. Good quality horn showed good cellular structure and no amorphous or filamentous intercellular material. Horn of moderate quality showed areas of material in the intercellular spaces which caused the individual cells to separate and were accompanied by a loss of internal, cellular structure. Poor quality horn showed large areas of cellular destruction, red blood cells in intercellular spaces and a disruption of the pattern of keratinisation. The ultrastructural appearance of the white line was a sensitive indicator of the quality of the horn. At the start of the study all the heifers had good feet with minimal or no solar haemorrhage. Four of the eight heifers with poor quality horn one month before calving went on to develop severe solar haemorrhage 10 to 20 weeks after calving, two developed moderate (grade 3) haemorrhage and two developed slight haemorrhage. The eight heifers with good quality horn at the start of the study all showed little or only moderate solar haemorrhage by 20 weeks after calving.

Animals↗
PubMed2003

Shrinking the biologic world--nanobiotechnologies for toxicology.

Although toxicologic effects need to be considered at the organismal level, the adverse events originate from interactions and alterations at the molecular level. Cellular structures and functions can be disrupted by modifications of the nanometer structure of critical molecules; therefore, devices used to assess biologic and toxicologic processes at the nanoscale will allow important new research pursuits. In order to properly assess alterations at these dimensions, nanofabricated tools are needed to detect, separate, analyze, and manipulate cells or biologic molecules of interest. The emergence of laser tweezers, surface plasmon resonance (SPR), laser capture microdissection (LCM), atomic force microscopy (AFM), and multi-photon microscopes have allowed for these assessments. Micro- and nanobiotechnologies will further advance biologic, clinical, and toxicologic endeavors with the aid of miniaturized, more sensitive devices. Miniaturized table-top laboratory equipment incorporating additional innovative technologies can lead to new advances, including micro total analysis systems (microTAS) or "lab-on-a-chip" and "sentinel sensor" devices. This review will highlight several devices, which have been made possible by techniques originating in the microelectronics industry. These devices can be used for toxicologic assessment of cellular structures and functions, such as cellular adhesion, signal transduction, motility, deformability, metabolism, and secretion.

Animals↗
PubMed2002

Formation of ionization clusters in nanometric structures of propane-based tissue-equivalent gas or liquid water by electrons and alpha-particles.

Despite the importance of ionization yield formation in sub-cellular structures a few nanometres in size, with regard to radiation damage our present knowledge in this respect is almost exclusively based on Monte Carlo simulations which in turn are based on cross section sets for water vapour or liquid water. Experimental data, although urgently needed, are still missing because the direct measurement of ionization yields in sub-cellular structures or, at least, in nanometric volumes of liquid water, is not yet possible. The best feasible way to overcome this problem of measurement at present, is the use of highly sophisticated counters filled with gases at low operating pressure to simulate target volumes a few nanometres in diameter at unit density. An indispensable prerequisite of the reliability of such measurements is, however, a check of the equivalence of the ionization yield produced in a specified target gas and the yield to be expected in liquid water or biological material. For this purpose, the ionization yield formation by electrons and alpha-particles in liquid water was simulated using the Monte Carlo method and compared with that produced in propane-based tissue-equivalent gas (composition by volume 55% C3H8, 39.6% CO2, 5.4% N2). After a short summary of the most important physical aspects of ionization cluster formation, new results are presented and discussed from the point of view of radiation physics and radiation biology.

Alpha Particles↗
PubMed1990

[Phenomenon of adaptive stabilization of cardiac structures and their protection].

Animal adaptation to repeated non-damaging stresses was shown to lead to the development of a phenomenon of adaptive stabilization of cardiac cellular structures. In isolated hearts, it appeared as a multifold decrease in reperfusion-induced arrhythmia severity, a sharply limited release of enzymes during the reperfusion paradox, and a lack or reduction in the contracture due to high calcium concentrations. The sarcoplasmic reticulum and mitochondria isolated from these hearts were found to be much more resistant to autolysis than the controls and to retain their function during prolonged storage. After coronary ligation in the adapted animals, the zone of acute ischemia was identical to that in the controls, and the necrotic zone measured 2 days later was reduced by more than 40%. Thus, the phenomenon of adaptive stabilization of cellular structures possesses no anti-ischemic effect, but forms the basis for a strong cytoprotective effect, thus providing protection of the heart from the necrotic action of ischemia. The author also discusses whether the genetic mechanism may be responsible for the phenomenon of adaptive stabilization of the structures and stress proteins may make a contribution to the phenomenon.

Adaptation, Physiological↗
PubMed2002

DNA-lipid interactions in vitro and in vivo.

The data on lipid-nucleic interactions and their role in vitro and in vivo are presented. The results of study of DNA-lipid complexes in absence and in presence of divalent metal cations (triple complexes) are discussed. The triple complexes represent the generation of cellular structures such as pore complexes of eucaryotes and "Bayer's junctions" of procaryotes. The participation of triple complexes in the formation of structure of bacterial and eucaryotic nucleoid and nuclear matrix is analysed. A model of formation of triple complexes and cellular structures and their role in DNA-lipid interactions are discussed.

Animals↗
PubMed1995

Crystal structure of cellular retinoic acid binding protein I shows increased access to the binding cavity due to formation of an intermolecular beta-sheet.

A recombinant form of murine apo-cellular retinoic acid binding protein I (apo-CRABPI) has been purified and crystallized at pH 5.0, and the crystal structure has been refined to an R-factor of 19.6% at a resolution of 2.7 A. CRABPI binds all-trans retinoic acid and some retinoic acid metabolites with nanomolar affinities. Coordinates of the holo form of CRABP were not available during the early stages of the study, and in spite of numerous homologs of known structure, phases were not obtainable through molecular replacement. Instead, an interpretable electron density map was obtained by multiple isomorphous replacement methods after improvement of the heavy-atom parameters with density modified trial phases. Two molecules of apo-CRABPI occupy the P3121 asymmetric unit and are related by pseudo 2-fold rotational symmetry. Unique conformational differences are apparent between the two molecules. In all of the family members studied to date, there is a lack of hydrogen bonds between two of the component beta-strands resulting in a gap in the interstand hydrogen bonding pattern. In the crystallographic dimer described here, a continuous intermolecular beta-sheet is formed by using this gap region. This is possible because of an 8 A outward maximum displacement of the tight turn between the third and fourth beta-strands on one of the molecules. The result is a double beta-barrel containing two apo-CRABPI molecules with a more open, ligand-accessible binding cavity, which has not been observed in other structures of a family of proteins that bind hydrophobic ligands.

Amino Acid Sequence↗
PubMed2000

Changes in lung structure and cellular division induced by tracheal obstruction in fetal sheep.

Increased expansion of the fetal lung, caused by obstruction of the fetal trachea, is a potent stimulus for growth and structural development of the fetal lung. Our aim was to analyze the changes in lung structure induced by fetal tracheal obstruction and to identify cell types that contribute to the growth response. Fetal sheep were exposed to 2, 4, or 10 days of tracheal obstruction (TO) and on day 128 of gestation (term "147 d"), were injected with 3H-thymidine 8 hours before tissues were collected. The right lung was fixed at 20 cm H2O and prepared for stereological and autoradiographic analysis. Alveolar wall thickness (7.8 +/- 0.3 microns vs 5.5 +/- 0.4 microns) and percent tissue space (27.9 +/- 0.9% vs 21.4 +/- 2.8%) were increased at 2 days of TO, but were not different from control at 4 and 10 days. The luminal surface area of the right lung increased gradually from 2.4 +/- 0.2 m2/kg in control fetuses to 3.6 +/- 0.4 m2/kg following 10 days of TO and this increase was accompanied by an increase in alveolar number (control: 808 x 10(6) +/- 81.9 x 10(6) vs 10d obstruct: 1254 x 10(6) +/- 63 x 10(6). Alveolar diameter increased at 2 days of TO (51.8 +/- 1.4 microns vs 43.8 +/- 1.9 microns), but was not increased further at 4 or 10 days. The percentage of dividing cells was increased at 2 days of TO (12.64 +/- 3.39% vs 1.73 +/- 0.31%), remained elevated at 4 days (5.01 +/- 0.27%), but had returned to control by day 10. The increase at 2 days was due to division of type II epithelial cells, fibroblasts, and endothelial cells. We conclude that increased expansion of the fetal lung induces time-dependent changes in lung structure and cell division rates; these include a transient increase in alveolar wall thickness, a rapid increase in alveolar number, and a gradual increase in luminal surface area. The latter is probably caused by an increase in alveolar number rather than an increase in the alveolar size.

Animals↗
PubMed1967

The columnar cells occurring in the parietal layer of Bowman's capsule. Cellular fine structure and protein transport.

The renal corpuscles of adult, C3H Swiss, male mice contain testosterone-sensitive, columnar cells in the parietal layer of Bowman's capsule. A study of the normal fine structure of these cells reveals several distinctive characteristics: a microvillous brush border; apical tubular invaginations and apical tubules; an elaborate infolding of the basal surface membrane forming cellular compartments, which contain numerous mitochondria; and a complex group of membrane-limited cytoplasmic inclusions. This appearance is remarkably similar to the fine structure of cells in the proximal convoluted tubule. 1 hr after an in vivo injection of horseradish peroxidase, numerous protein-absorption droplets occur in the columnar cell cytoplasm. The speed and cytomorphology of protein transport by these capsular cells closely resemble the handling of peroxidase by the proximal convoluted tubule. Origins for these testosterone-sensitive cells are discussed briefly. Morphological evidence is presented for the differentiation of squamous cells in Bowman's parietal capsule into columnar cells, which appear structurally and functionally identical with proximal convoluted tubular epithelium.

Animals↗
PubMed1999

Enzymatic antioxidant defence mechanism in rat intestinal tissue is changed after ischemia-reperfusion. Effects of an allopurinol plus antioxidant combination.

OBJECTIVES: To establish the antioxidant status of rat intestinal tissues after ischemia-reperfusion and to determine if pretreatment with an allopurinol and antioxidant vitamin combination gives any protection against mucosal injury. EXPERIMENTAL ANIMALS: Twenty rats were divided into 4 groups of 5 animals each. METHODS: Group 1 (control) rats were not subjected to ischemia-reperfusion and received no allopurinol plus vitamin combination; group 2 rats received vitamins C (200 mg/kg) and E (100 mg/kg) and allopurinol (50 mg/kg) combination daily for 3 days preoperatively; group 3 rats were subjected to ischemia-reperfusion only; and group 4 rats were subjected to ischemia-reperfusion and received the vitamin and allopurinol combination. MAIN OUTCOME MEASURES: Activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase (CAT) enzymes, the level of thiobarbituric acid-reagent substances (TBARS) and histologic grading of tissue samples. RESULTS: SOD and GSH-Px activities were decreased, but the CAT activity and TBARS level increased. Pretreatment of the rats with the allopurinol-vitamin C-vitamin E combination did not have any significant effect on the enzyme activities. However, it resulted in important reductions in the TBARS tissue levels. Histologic investigation revealed significant mucosal injury in group 3 rats compared with group 4 rats (mean [and standard deviation] for grading, 4.6 [0.5] versus 1.8 [0.4]). CONCLUSIONS: The enzymatic antioxidant defence system was significantly changed after ischemia-reperfusion and intestinal tissue was exposed to increased oxidant stress, the results of which were peroxidation of some cellular structures and increased concentrations of oxidative products. Although antioxidant treatment did not drastically affect the enzyme activities or afford complete protection of cellular structures against deformation, it apparently could eliminate oxygen radicals and prevent peroxidative reactions.

Allopurinol↗
PubMed1990

The influence of nifedipine and mioflazine on mitochondrial calcium overload in normoxic and ischaemic guinea-pig hearts.

The influence of nifedipine (20 nM) and mioflazine (300 nM), i.e. concentrations inducing a 60-70% recovery of cardiac function during reperfusion of globally ischaemic guinea-pig working hearts, on the mitochondrial calcium content was investigated in normoxic, globally ischaemic and reperfused globally ischaemic guinea-pig working hearts. Mitochondrial calcium was determined electronmicroscopically with oxalate-pyroantimonate method. In normoxic hearts both nifedipine and mioflazine reduced the mitochondrial calcium content. Global ischaemia for 45 min and subsequent reperfusion for 25 min resulted in a pronounced mitochondrial calcium overload and damage to the cellular structure. In ischaemic and in reperfusion hearts the drugs maintained mitochondrial calcium at pre-ischaemic levels and decreased the damage to the cellular structure.

Animals↗