SEARCH · PubMed Health

Results for “APPARATUS”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,009 records · Page 56Linked to original sources

PubMed1982

Morphogenesis of the renal juxtaglomerular apparatus and peripolar cells in the sheep.

The morphogenesis of the juxtaglomerular apparatus and peripolar cells was studied in the metanephros of fetal sheep (from 24 to 147 days of gestation) using light and electron microscopy. The first juxtaglomerular apparatus was detected at 45 days of gestation, following constriction of the edges of Bowman's capsule and formation of the vascular pole of the renal corpuscle. Mesenchymal cells gave rise to lacis cells and to smooth muscle and epithelioid cells of the juxtaglomerular arterioles. Epithelioid cells developed only sparse cytoplasmic granulation, first detectable at 92 days. The macula densa developed from tubular cells at the junction of the middle and upper limbs of the S-shaped body of the developing nephron. Peripolar cells arose from epithelial cells in the lower limb of the S-shaped body, at the constricting edges of Bowman's capsule, and formed a cuff around the origin of the glomerular tuft. Cytoplasmic granules were first detected in peripolar cells at 53 days, and remained more prominent than epithelioid cell granulation throughout gestation.

Animals↗

PubMed1975

Studies on the juxtaglomerular apparatus. IV. Freeze-fracturing of membrane surfaces.

The juxtaglomerular apparatus of the rat was studied after freeze-fracturing with special respect to intercellular junctions. It was found that juxtaglomerular granulated cells of the vas afferens are interconnected by gap junctions to adjacent cells (granulated cells, possibly also smooth muscle cells). Gap junctions have also been found on the surface of lacis cells and mesangial cells. It is therefore concluded that these cells of the juxtaglomerular apparatus and the glomerulus--granulated cells (possibly also smooth muscle cells) of the vas afferens, lacis cells and mesangium cells--form a functional system reacting in a coordinated manner to physiological stimuli.

Animals↗

PubMed1978

Effects of colchicine on ultrastructure of the lactating mammary cell: membrane involvement and stress on the Golgi apparatus.

The effects of colchicine on ultrastructure of the lactating mammary cell in the rat and goat were studied by electron microscopy. Changes in tissue of the rat were examined over time (1, 2 and 4 h). The goat gland was evaluated by comparing ultrastructure of tissue at the time of maximum milk flow suppression induced by the drug with that of untreated tissue. Colchicine produced notable changes in the tissue of both species: 1) the secretion of lipid droplets and Golgi vesicle contents (exocytosis) was inhibited and the droplets and vesicles became randomly distributed throughout the cell, 2) the Golgi apparatus was significantly reduced in size, 3) casein and lipid continued to be synthesized as evidenced by greater numbers of secretory vesicles and increased sizes of casein micelles and lipid droplets, 4) secretory vesicles showed a propensity to cluster around lipid droplets, 5) isolated microtubules were found occasionally in the control tissue, ordinarily in the vicinity of the Golgi apparatus, but rarely in the colchicine-treated tissue. These observations indicate that colchicine has two effects leading to suppression of exocytosis in the mammary cell: one involves early interference with capacity of secretory vesicle membranes to fuse and a further effect, related to higher concentrations of colchicine, causes intracellular disorganization and loss of polarity. Microtubules were not seen as directly involved in the mechanisms of exocytosis. The secretion of milk fat globules is coupled to exocytosis and thereby is also inhibited by colchicine.

Animals↗

PubMed1995

Microsomal casein kinase II in endoplasmic reticulum- and Golgi apparatus-rich fractions of ROS 17/2.8 osteoblast-like cells: an enzyme that modifies osteopontin.

Osteopontin is an acidic phosphoprotein containing casein kinase II (CKII) phosphorylatable sites and an acidic amino acid cluster. The metabolically 32P-labelings of both serines and threonines in vitro in osteopontin immunoprecipitated from rat osteoblast-like ROS 17/2.8 cells may suggest that casein kinase II catalyzes this modification. The enzyme occurs in microsomal fractions of rat osteoblast-like ROS 17/2.8 cells. Subcellular fractions containing endoplasmic reticulum and Golgi apparatus were isolated by differential centrifugation and were identified according to their ultrastructures and the presence of marker enzymes such as glucose-6-phosphatase and thiamine pyrophosphatase, respectively. both fractions phosphorylated the partially dephosphorylated osteopontin and the specific substrate peptide RRREEETEEE. Endoplasmic reticulum-catalyzed peptide phosphorylation was 2.7 times lower than that of Golgi although both endoplasmic reticulum- and Golgi-catalyzed peptide reactions were 50% inhibited by 20 and 100 ng/ml heparin, respectively. Western blot analysis revealed that both fractions contained osteopontin and microsomal CKII. Furthermore, microsomal CKII was immunogold-labeled in endoplasmic reticulum and Golgi apparatus. Heparin inhibition and utilization of [gamma-32P]GTP as a phosphate donor by both fractions confirmed their capacity to phosphorylate osteopontin. The results suggest that microsomal CKII modifies the acidic matrix proteins during transportation. These matrix phosphoproteins may participate in the mineralization process of hard tissues.

Amino Acid Sequence↗

PubMed1988

Ultrastructural demonstration of lectin binding sites in the Golgi apparatus of rat epiphyseal chondrocytes.

Binding sites for wheat germ agglutinin (WGA), Dolichos biflorus agglutinin (DBA), Ricinus communis I agglutinin (RCA I) and Limax flavus agglutinin (LFA) have been ultrastructurally detected in rat epiphyseal chondrocytes by a post-embedding cytochemical technique using colloidal gold as marker. The four lectins labelled exclusively the Golgi apparatus of chondrocytes embedded in Lowicryl K4M resin by two different methods. WGA binding sites were localized in medial and trans cisternae as well as in immature secretory vesicles, whereas those for DBA were seen concentrated in cis and medial cisternae. Labelling with both RCA I and LFA lectins was distributed throughout all the cisternae of the Golgi stack, and the latter also in vesicles and tubules at the trans face. Neuraminidase pretreatment of the sections abolished LFA staining, decreased reaction with WGA and increased that with RCA I, while it did not affect DBA staining. After chondroitinase ABC treatment only the RCA I reaction was modified, revealing new binding sites in the trans Golgi face, secretory granules and extracellular matrix. These results indicate that the distribution of subcompartments in the Golgi apparatus of chondrocytes is different from that in cells secreting glycoproteins as major products.

Animals↗

PubMed1984

The nerves of the juxtaglomerular apparatus of man and other mammals contain the potent peptide NPY.

The juxtaglomerular apparatus, a neuroendocrine unit located in the vascular pole of the glomerulus and influencing blood pressure by the secretion of renin, is known to have a rich supply of monoaminergic nerve fibres. Neuropeptide Tyrosine (NPY), a newly discovered, potent, vasoconstrictor peptide of 36 amino acids, has been found by immunocytochemistry to be present in a dense plexus of fibres around the juxtaglomerular apparatus of man, monkey, mouse, hamster, rat and guinea pig. NPY-immunoreactivity was markedly depleted after chemical sympathectomy by 6-hydroxydopamine. The concentration of NPY within the whole mouse kidney was 29.6 +/- 6.8 pmol/g and fractionation of the extracts demonstrated that the NPY-like immunoreactivity co-eluted from the column in the same position as the porcine NPY standard. The role of this peptide in renal physiology and pathology now needs urgent investigation.

Animals↗

PubMed1978

Localization of somatostatin-like immunoreactivity in the Golgi apparatus of central and peripheral neurons.

With the indirect immunofluorescence technique of Coons and collaborators somatostatin-like immunoreactivity (SLI) was observed in certain neurons of the central and peripheral nervous system of the rat. In the cell bodies a strong SLI was observed with a distribution resembling that of the Golgi apparatus. In addition a weak SLI was diffusely distributed in the cytoplasm. After photography the sections processed for immunocytochemistry were stained with the thiamine pyrophosphatase technique of Novikoff and Goldfischer. The latter technique is assumed to be a specific marker for the Golgi complex. It was found that the strong SLI and the thiamine pyrophosphatase activity had an identical distribution. Thus, one pool of somatostatin appears to be localized to the Golgi apparatus.

Animals↗

PubMed1989

Lectin-gold cytochemistry of the Golgi apparatus in rabbit luteal cells, with special emphasis on the formation of a lysosomal-type membrane.

In rabbit luteal cells embedded in glycolmethacrylate and stained with PTA at low pH highly glycosylated membrane patches can be observed after vesiculation of the trans-Golgi network. As these membranes could be prelysosomal, their sialic acid content was investigated by post-embedding labeling with Limax flavus agglutinin (LFA)/fetuin-Au. Additional labeling of the Golgi apparatus was performed with Wheat germ agglutinin (WGA)/ovomucoid Au, Ricinus communis agglutininI (RCAI)/Au and Helix pomatia agglutinin (HPA)/Au. The sections were then counterstained with PTA at low pH, which allows a clear distinction between the elements of the trans-Golgi network (G2-G1) and the saccules of the stack (g). With WGA, LFA and RCAI the trans-Golgi network was observed to be clearly more reactive than the stack. After vesiculation most intense labeling was found over the highly glycosylated vacuolar membranes derived from the G2-element. The limiting membrane of lysosomes, the MvB's and the plasma membrane also reacted strongly. Colloidal gold particles were also found over the membranes of the vacuoles derived from G1. The Golgi stack showed a lower reactivity and label for all three lectins could be found over three to four saccules of the stack (g3-g4). The matrix of the lysosomes was slightly labeled. Labeling with HPA was absent from the trans saccules and was consistently found in the cis and cis-most (g4-g5) saccules of the stack. Some cytoplasmic vesicles near the cell border were also labeled. With our procedure the Golgi apparatus can easily be detected and it is apparent that in rabbit luteal cells the highest lectin reactivity is found in the trans-Golgi network.(ABSTRACT TRUNCATED AT 250 WORDS)

Agglutinins↗

PubMed1984

Cytochemical study on the effect of aluminum on neuronal Golgi apparatus and lysosomes.

Ultracytochemical reactions for enzymatic markers were applied to study the effect of aluminum on some cell organelles of neurons in the Ammon cortex and spinal cord in rabbits. The results showed that aluminum caused an appearance of secondary lysosomes and an increase in the number of lysosomes. The latter finding was endorsed by statistical analysis of Ammon neurons using a two-sided t-test. Concomitantly, decrease of the intensity of the reaction for thiamine pyrophosphatase (TPPase) and nucleoside diphosphatase (NDPase) in the Golgi apparatus was found. The reaction for NDPase in the endoplasmic reticulum remained unchanged. Cytochemical reactions for alkaline phosphatase and Mg2+-activated adenosine triphosphatase in the plasmalemma of neurons were negative both in control and in aluminum-treated animals. Our data point to the activation of the system of intracellular digestion and suppression of the enzymatic activities (NDPase, TPPase) of the Golgi apparatus in CNS neurons of rabbits treated with aluminum.

Acid Anhydride Hydrolases↗

PubMed1985

Qualitative and quantitative ultrastructural alterations in hepatocytes of rats prenatally exposed to ethanol with special reference to mitochondria, golgi apparatus and peroxisomes.

To assess the effect of ethanol on the liver of the offspring of alcohol-fed rats, the hepatocytes of newborn rats whose mothers were fed: a) a liquid diet containing alcohol, b) the same diet isocalorically balanced, or c) a chow diet, were analyzed using both quantitative and qualitative electron microscopy as well as cytophotometric and biochemical methods. Hepatocytes of chow-fed and pair-fed controls showed differences in the amounts of glycogen and lipids as well as in several stereologically measured variables including mitochondria, Golgi apparatus and smooth endoplasmic reticulum. These differences are probably due to the composition of the diet. Rats prenatally exposed to alcohol showed increases in the hepatocyte and mitochondria volumes and in the number of peroxisomes. Moreover, the Golgi apparatus of these cells appeared disorganized and composed exclusively of small size vesicles, suggesting an impairment of their function.

Animals↗

PubMed1994

Targeting of proteins to the Golgi apparatus.

The Golgi apparatus maintains a highly organized structure in spite of the intense membrane traffic which flows into and out of this organelle. Resident Golgi proteins must have localization signals to ensure that they are targeted to the correct Golgi compartment and not swept further along the secretory pathway. There are a number of distinct groups of Golgi membrane proteins, including glycosyltransferases, recycling trans-Golgi network proteins, peripheral membrane proteins, receptors and viral glycoproteins. Recent studies indicate that there are a number of different Golgi localization signals and mechanisms for retaining proteins to the Golgi apparatus. This review focuses on the current knowledge in this field.

Biological Transport↗

PubMed1979

Different aspects of membrane differentiation at the inner side (GERL) of the Golgi apparatus in rabbit luteal cells.

After luteinization, during the growth phase, rabbit luteal cells showed a well-developed Golgi apparatus, which was clearly reduced at the end of pseudo-pregnancy. During this whole period, acid phosphatase was demonstrated in the saccules (g) of the Golgi stack and in the innermost Golgi element (G2), which may be part of GERL. Between both acid phosphatase-positive compartments, a negative or slightly positive element (G1) was present paralleling the saccules of the Golgi stack. This element was composed of cisternal (G1 c) and perforated portions (G1 p) and directly bordered the thiamine pyrophosphatase-positive saccules of the Golgi stack (g1 -g2). Arylsulphatase activity was present in two saccules in the middle of the stack (g3 -g4) and in the innermost Golgi element (G2). In the acid phosphatase and arylsulphatase reactions the limiting membrane of the lysosomes was more reactive than the matrix. After phosphotungstic acid staining at a low pH, the inner elements of the Golgi apparatus (G1 and G2) and the border of the lysosomes were heavily contrasted. The lysosomal matrix and the other Golgi stack saccules were either almost unstained or displayed a clearly lower contrast. It is concluded that the cytochemical difference between Golgi (g) and GERL (G) membranes is most probably the result of a specific process of membrane differentiation, which takes place at G1. There is also evidence that the lysosomal matrix hydrolases may be formed in the saccules of the Golgi stack. The strongly phosphotungstic acid-positive inner elements are, although more extended, comparable in large part with the GERL elements as described in neurons (Novikoff et al., 1971).

Acid Phosphatase↗

PubMed1981

The axonal reticulum in the neurons of the superior cervical ganglion of the rat as a direct extension of the Golgi apparatus.

Adrenergic neurons from the superior cervical ganglion of the rat have been studied with the chromaffin reaction and the zinc iodide-osmium tetroxide method. Phosphotungstic acid staining at a low pH and a combined acid phosphatase reaction and phosphotungstic acid staining have also been performed on glycolmethacrylate-embedded tissue. The results indicate that phosphotungstic acid-positive elements lacking acid phosphatase activity are present at the inner side of the Golgi apparatus. These elements give rise directly to reticular differentiations, carrying catecholamines, or to tubular extensions, representing the origin of the axonal reticulum. On these tubules, reticular differentiations can again be formed at any level. In the cell body, the differentiations are mainly found close to the neurolemma. In the axons, they are especially abundant at the axon terminals. Large granules may be associated with the reticular differentiations and small and large granules may detach from them. It is concluded that the whole catecholamine-producing and/or -storing system in sympathetic neurons can be considered as a direct extension of the Golgi apparatus, set up for local catecholamine synthesis. The relative importance of small and large granules along this system may reflect th functional status of the nerve cell.

Acid Phosphatase↗

PubMed1984

Presence of an osmiophilic feltwork distinct from the Golgi apparatus in spinal ganglion cells of the rat.

Rat dorsal root ganglia were osmicated for 48 h at 42 degrees C in a 2% unbuffered aqueous solution of osmium tetroxide. In addition to the osmiophilic cis-element of the Golgi apparatus, the osmium stained a cytoplasmic structure which, although present in the perikaryon of all ganglionic neurons, was well developed in type B1 cells. In photographic stereopairs of 1-2 microns thick sections examined with the electron microscope at 100 kV, these osmiophilic elements appeared as long, wavy thread-like elements with fusiform enlargements. Their average diameter was smaller than that of the thinner cisternae of the smooth endoplasmic reticulum. Occasionally branched, these osmiophilic structures were oriented in all directions of space. When examined in 1.5-7 microns thick sections with a high voltage electron microscope, they formed an osmiophilic feltwork which extended from the juxtanuclear to the subplasmalemmal regions of the perikaryon. It was not connected with the osmiophilic cis-element of the Golgi apparatus. In sections of glutaraldehyde-fixed tissues impregnated with the double impregnation technique or postfixed with reduced osmium, the osmiophilic tubules were clearly distinguished from microtubules, cisternae of endoplasmic reticulum or endocytic structures.

Animals↗

PubMed1995

Three-dimensional organization of stable microtubules and the Golgi apparatus in the somata of developing chick sensory neurons.

Microtubules play a role important in regulating cell shape and in mediating organelle movements. These functions are especially important in elaborately branched neurons, which have many stable microtubules that are resistant to cold and to microtubule depolymerizing drugs. We examined the three-dimensional organization of microtubules in cell bodies of cultured chick embryo sensory neurons, using confocal laser scanning microscopy. Microtubules were visualized with antibodies against alpha-tubulin and post-translationally modified forms of alpha-tubulin that accumulate in older microtubules. Optical sections were collected through neuronal somata, and the images were reconstructed in three dimensions. In neuronal perikarya a dense network of older microtubules is co-localized with the Golgi apparatus. This complex of the Golgi and older microtubules usually lies beneath the cell nucleus and is oriented toward the substratum. From this region, older microtubules extend into each neurite. A cage of older microtubules extends around the nucleus to the top of the perikaryon. The stability of these microtubules was confirmed by their resistance to the depolymerizing drug, nocodazole. This arrangement of stable microtubules in a developing neuron provides a supporting cytoskeleton and a transport pathway for movement of cytoplasmic components between the Golgi apparatus, the perikaryon and developing neurites.

Animals↗

PubMed1995

Nitric oxide synthase is localized predominantly in the Golgi apparatus and cytoplasmic vesicles of vascular endothelial cells.

The localization of nitric oxide synthase (NOS) in vascular endothelial cells of submucosal blood vessels from the guinea-pig ileum was examined using NADPH diaphorase histochemistry at the light microscopic level, and endothelial NOS immunohistochemistry at the light and electron microscopic level. The pattern of staining observed following NADPH diaphorase histochemistry and endothelial NOS immunohistochemistry was identical. Endothelial cells of the arterioles, capillaries and venules showed small patches of intense, perinuclear staining. Under the electron microscope, endothelial NOS immunoreactivity was found predominantly in association with the Golgi apparatus and with the membranes of some vesicles. Small regions of the plasma membrane and the rough endoplasmic reticulum also showed some immunoreactivity. The presence of NOS in the Golgi apparatus and in vesicles raises the possibility that NOS may be exteriorized by endothelial cells, and hence that nitric oxide is synthesized extracellularly.

Animals↗

PubMed1987

Arrest of proteolipid transport through the Golgi apparatus in Jimpy brain.

Immunocytochemical investigations were performed on Jimpy and control mouse brains using three specific anti-myelin proteolipids antisera: immunoaffinity purified multivalent anti-(PLP + DM-20) proteolipid antibodies, anti-C-terminal hexapeptide 271-276 and anti-tridecapeptide 117-129 antisera. The results show that oligodendrocytes and myelin sheaths in normal mouse brain are labelled to the same extent by the three specific antisera; in contrast, in Jimpy brain these cellular structures are only stained by the multivalent antibodies and the site-specific, anti-tridecapeptide antiserum. The absence of labelling with C-terminal hexapeptide antiserum in mutant brain is interpreted as the result of either a large deletion or a point mutation producing a frameshift in the C-terminal part of the sequences of the proteolipids PLP and DM-20. Furthermore, we show that this mutation prevents the normal transport of proteolipid molecules through the Golgi apparatus. The existence of a minor, extra-Golgi apparatus metabolic route for proteolipids to myelin structures is also discussed.

Animals↗

PubMed1998

One hundred years of the Golgi apparatus: history of a disputed cell organelle.

In April 1898 at the Medico-Surgical Society of Pavia, Camillo Golgi communicated his finding of a novel intracellular structure, which he had detected in nerve cells by means of a variant of the "black reaction" he had developed earlier for the staining of the nervous tissue. On the basis of the "netlike" appearance and intracellular location of this structure, Golgi defined it as "internal reticular apparatus". The reality of the organelle was debated for fifty years, since some investigators believed that the structure, which was soon designated as Golgi apparatus, represented an artifact of metallic impregnation. The controversy was finally solved in the mid-1950s by studies based on electron microscopy. Linked to the cell organelle he had discovered, Golgi's contributions to cytology had a great impact on biomedical sciences of the twentieth century.

Animals↗