Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.1.1.7 (acetylcholinesterase)
28,390 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The development of the rat adrenal medulla was studied at the ultrastructural level with particular emphasis placed on early discrimination of different catecholamine-storing cells. The first granule-containing cells, phaeochromoblasts, were seen at day 15 of gestation migrating into the anlage of the cortex. These cells were characterized by a few small granules (80-120 nm in diameter) and a high nuclear to cytoplasmic ratio. Presumably due to differentiation into chromaffin cells, they were no longer present after the eight postnatal day. Maturation of phaeochromoblasts was indicated by an increase in number and size of their storage granules and a decrease in the nuclear to cytoplasmic ratio. Noradrenaline and adrenaline cell types were first clearly discernible at day 21 of gestation. Another cell type, a giant cell, was also recognized at this stage. In the adult animal, noradrenaline, two morphologically different types of adrenaline, and small granule-containing cells were observed. By applying acetylcholinesterase histochemistry, it was found that at day 17 of gestation a small population of granule-storing cells showed strong positive staining in the endoplasmic reticulum. In the adult animal this cell type was further characterized by small-storage granules. Other chromaffin cells began to show weak staining with the endoplasmic reticulum at day 19 of gestation. This staining appeared more frequently within adrenaline than noradrenaline cells. However, even in the adult animal many cells of both types were completely negative. It is concluded that acetylcholinesterase histochemistry is a useful method for early discrimination of small granule-containing cells in the developing rat adrenal medulla.
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PMID:Catecholamine-storing cells in the adrenal medulla of the pre- and postnatal rat. Acetylcholinesterase as a means for early discrimination of cell types. 724 40

The biosynthesis of acetylcholinesterase in mammalian erythroid cells during differentiation and maturation was studied using a cytochemical method. Acetylcholinesterase was actively synthesized in basophilic erythroblasts I and II, and polychromatophilic erythroblasts, where it was present in the nuclear membrane, endoplasmic reticulum and Golgi apparatus. In orthochromatophilic erythroblasts the enzyme was present only in the Golgi apparatus, thus suggesting the end of the biosynthesis of acetylcholinesterase at this stage of maturation. In mouse and human marrow, evidence was also found suggesting the secretion of acetylcholinesterase into the extracellular compartment. No acetylcholinesterase reaction product was found in cat erythroblasts.
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PMID:Acetylcholinesterase in mammalian erythroid cells. 733 59

The acylation of lysophosphatidylcholine by isolated subcellular fractions of guinea-pig cerebral cortex has been determined. The microsomal fraction contained the highest acylation activity, in terms of both specific and total activity. In all particulate fractions, including synaptic plasma membrane and mitochondria, there was a high correlation (correlation coefficient r = 0.90; P less than 0.001) between acylation and the activity of the microsomal enzyme, NADPH-cytochrome c reductase. No correlation existed between acylation and the activities of (Na+ + K+)-ATPase, acetylcholinesterase or succinate dehydrogenase. Acyl-CoA synthetase and lysophosphatidylcholine/acyltransferase, the individual enzymes responsible for acylation were enriched in the microsomal fraction. The activities of both enzymes in subcellular fractions correlated well with those of NADPH-cytochrome c reductase, with the exception that acyl-CoA synthetase activity in the mitochondrial fraction was largely independent of endoplasmic reticulum. Neither synaptic plasma membranes nor mitochondria appeared to possess significant amounts of acyltransferase activity. The results indicate that the acylation of lysophosphatidylcholine is confined to the endoplasmic reticulum, and that activity present in the synaptic plasma membrane or mitochondrial fraction is attributable to microsomal contamination.
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PMID:The acylation of lysophosphatidylcholine by subcellular fractions of guinea-pig cerebral cortex. 737 36

In the adult pigeon ciliary ganglia peculiar membrane-limited structures were constantly observed in the peripheral cytoplasm of choroid neurons. They are continuous with profiles of the endoplasmic reticulum and/or interconnected with each other. In addition they contain a marked acetylcholinesterase histochemical reaction. These data on the whole suggest that these structures are an integral part of the endoplasmic reticulum system, possibly acting as storing sites of proteic material moving along the pathways of the endoplasmic reticulum system.
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PMID:[Ultrastructural observations on choroid neurons of ciliary ganglia]. 744 52

Ultrastructural localization of acetylcholinesterase activity was studied in primary cultures of the substantia nigra microdissected from newborn rat brains. Light microscopic observations were also made on the characteristics of dopamine neurones and acetylcholinesterase containing cells in these cultures. Ultrastructurally acetylcholinesterase activity was localized in the nuclear envelope and rough endoplasmic reticulum of neurones, which had deeply infolded, round or oval nucleus, a prominent Golgi apparatus and varying amounts of rough endoplasmic reticulum. In the neuropil acetylcholinesterase activity was seen within microtubules of neuronal processes and in the rough endoplasmic reticulum of dendrites. The enzyme activity was also demonstrated within the nuclear envelope and rough endoplasmic reticulum of probably capillary endothelial cells. Dopaminergic neurones were identified on the basis of the green catecholamine fluorescence they exhibited. Small dopaminergic neurones could be observed and there was indirect evidence that these cells did not stain for acetylcholinesterase.
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PMID:Ultrastructural localization of acetylcholinesterase activity in primary cultures of rat substantia nigra. 746 13

Primary cultures prepared from embryonic chick pectoral muscle were subjected to heat shock, and the effect on acetylcholinesterase activity in the cultures was examined. A rapid recovery in enzyme activity was observed soon after an initial heat shock-induced drop and was shown to be independent of de novo synthesis of protein, since it could occur in the presence of an inhibitor of protein synthesis. Lectin binding and sucrose gradient centrifugation studies suggested that molecular monomers and dimers found in the endoplasmic reticulum are involved in the observed recovery of acetylcholinesterase activity. Enhanced activation of a pre-existing pool of inactive enzyme was clearly not the main agent of the recovery in enzymic activity. Recovery relied principally on restoration of the activity of previously active, heat-denatured acetylcholinesterase molecules found in the endoplasmic reticulum. Possible agents involved in the recovery of enzymatic activity might be heat shock proteins acting as molecular chaperones.
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PMID:The activity of an endoplasmic reticulum-localized pool of acetylcholinesterase is modulated by heat shock. 787 13

The interrelationship between signal-mediated endoplasmic reticulum retention and control of subunit assembly in secreted complex proteins was examined in recombinant 293 cells expressing human acetylcholinesterase (HuAChE). This was achieved by analyzing the mutual effects of co-residing retention and dimerization signals on enzyme secretion by transfected cells. The function of putative signals within the COOH-terminal tetrapeptide CSDL of HuAChE was examined by site-directed mutagenesis. The CSDL tetrapeptide carries the free cysteine (Cys-580) involved in subunit assembly, yet it fails to function as a KDEL-type retention signal. This was demonstrated by mutations that increase similarity to the canonical retention signal (substitution of CSDL by KSDL) or those that deviate from it (substitution to CSAL). Cells expressing both types of mutants exhibited cell-associated HuAChE levels identical to that of wild type enzyme. Appendage of an engineered KDEL retention signal to a dimerization-impaired HuA-ChE subunit (the C580A mutant) resulted in intracellular retention of large amounts of fully active enzyme not prone to proteolytic degradation. On the other hand, attachment of KDEL to a native, dimerization-competent HuAChE polypeptide did not lead to intracellular retention and allowed efficient secretion of enzyme to the cell growth medium. Yet, appendage of KDEL to the native HuAChE led to some retardation in the transport of enzyme molecules through the Golgi apparatus, as manifested by increase in cellular population of endo H-resistant dimers, when compared with wild type enzyme. Taken together, these results indicate (alpha) that sub-unit dimerization mediated by the COOH-terminal cysteine of HuAChE can reverse the signal-mediated retention by masking recognition of KDEL by its cognate receptor and (b) that the native sequences of the acetylcholinesterase subunit polypeptide do not appear to function as a coupled retention/dimerization signal in the control of secretion of assembled enzyme molecules.
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PMID:Reversal of signal-mediated cellular retention by subunit assembly of human acetylcholinesterase. 807 24

The development of neuron-like cholinergic immunophenotypes by adrenal chromaffin cells was studied in 10-week-old mouse adrenal medullary grafts. Fragments of chromaffin tissue were implanted into mouse hippocampus, and antibodies specific for neurofilaments (NF), neuron-specific enolase (NSE), choline acetyltransferase (ChAT), acetylcholinesterase (AChE), and phenylethanolamine-N-methyltransferase (PNMT) were applied to the grafts. Adrenal medulla grafts survived well and most of the transplanted cells were either round or polygonal. A minority of chromaffin cells elaborated an intermediate or sympathetic neuron phenotype. Chromaffin cells showed pronounced immunoreactivity for NSE in their perikarya and axon-like processes: immunoreactivity for NF was only found in a few processes. In adjacent immunohistochemically stained sections, the transplanted cells stained for ChAT and AChE. At the electron-microscope level, the immunohistochemical reactions for the two acetylcholine-related enzymes were mainly located on the endoplasmic reticulum and in cell processes. Immunoreactivity for PNMT was found to decline in transplanted chromaffin cells below that of normal adrenal medulla. These observations suggest that, in adrenal medullary grafts implanted into the hippocampus, chromaffin cells are endowed with neuron-like cholinergic immunophenotypes.
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PMID:Mouse adrenal chromaffin cells can transform to neuron-like cholinergic phenotypes after being grafted into the brain. 824 6

Toxicities of pesticidal mixtures in biological systems have not been explored adequately. Therefore, mixtures of ten widely used pesticides were evaluated for their toxicity in ICR male mice (21-24 g). Mice were given four mixtures of alachlor, aldrin, atrazine, 2,4-dichlorophenoxyacetic acid, DDT, dieldrin, endosulfan, lindane, parathion and toxaphene, at 0.01, 0.1, 1.0 and 10 ppm of each of these pesticides, in drinking water for 90 days ad libitum. Also, two mixtures at 2.5 and 5 mg kg-1 of each pesticide in 7.5% Tween-80 in water were administered to additional groups of mice by oral intubation daily for up to 14 days. In relation to the control, the 90-day exposure caused a dose-dependent increase in the liver/body weight ratio (3-44%), a decrease in the pentobarbital (60 mg kg-1, i.p.)-induced sleep time (11-79%) and an increase in the metabolism of aniline (233-399%), amidopyrine (79-231%), phenacetin (127-318%) and benzo[a]pyrene (286-1633%) in the 9000 g hepatic supernatants from the mixture-treated mice. Proliferation, dilatation and fragmentation of the endoplasmic reticulum and scattering of ribosomes were noticed with mixture livers. In the 5 mg kg-1 group, 90% of the animals died by Day 8; incidence of death was considerably less in the 2.5 mg kg-1 group. The serum cholinesterase activity was inhibited by ca. 50% in the 2.5 and 5 mg kg-1 groups on either one or both of Days 8 and 15; the liver/body weight ratio increased by 24-79% and the pentobarbital-induced sleep time decreased by 80-96%.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Toxicological evaluation of mixtures of ten widely used pesticides. 832 87

Transport and secretion of recombinant human acetylcholinesterase (rHuAChE) were studied in transfected human 293 cells expressing either the oligomerized soluble enzyme or a monomeric mutant derivative in which Cys-580 was substituted by alanine (C580A). In cells expressing the wild-type enzyme, the gradual assembly of newly synthesized intracellular rHuAChE monomers into oligomers occurs within the endoplasmic reticulum. Secretion of mature wild-type enzyme into the medium is efficient and appears to be exclusive to multimeric forms. Consistently, intracellular oligomers, but not monomers, are endoglycosidase H-resistant, indicating that only oligomers undergo terminal glycosylation in the wild-type enzyme. In contrast, in cells expressing the dimerization-defective C580A mutant, newly synthesized rHuAChE monomers undergo terminal glycosylation and are secreted into the medium as efficiently as wild-type multimers. No significant difference between the intracellular transport rates of wild-type rHuAChE oligomers and mutant C580A monomers was revealed by probing with specific lectins. In both systems, transport and processing prior to the trans-Golgi galactosylation compartment appear to be rate-limiting, whereas the following passage to the cell surface is rapid. In conclusion, we suggest that in the presence of a free cysteine at the COOH terminus of the rHuAChE polypeptide, secretion of monomers is not effectuated, whereas in its absence, monomers are exported from the endoplasmic reticulum and are capable of traversing the entire secretory pathway.
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PMID:Interrelations between assembly and secretion of recombinant human acetylcholinesterase. 841 26


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