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)

Ancylostoma ceylanicum, the human hookworm parasite, exhibited significant secretion of cholinesterase when maintained in vitro in RPMI-1640 medium. Secretion of the enzyme was linear up-to 4 hours of incubation. About 40 percent of the total cholinesterase activity was localized in the soluble fraction, while remaining activity was associated with the particulate fraction of the nematode. Exposure of the hookworms to colchicine in vitro caused significant inhibition in secretion of the enzyme by the parasite with concomitant accumulation of cholinesterase within the adult worms. Vinblastine did not show noticeable effect on the enzyme secretion as well as activity within the parasite. Incubation of hookworms with some benzimidazole anthelmintics viz., mebendazole or albendazole significantly reduced the capacity of the worms to secrete cholinesterase and increase in enzyme activity within the parasite. Adult worms recovered from mebendazole treated hamsters exhibited about 3 fold greater activity of cholinesterase as well as significantly lower capacity to secrete cholinesterase in vitro as compared to the worms recovered from untreated animals. These observations indicate role of microtubules in the secretion of cholinesterase by hookworms and as a target for the action of benzimidazole anthelmintics.
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PMID:Secretory cholinesterase of Ancylostoma ceylanicum: effect of tubulin binding agents and benzimidazole anthelmintics. 173

A serum-free medium culture was developed in order to study the secretory behavior of neurons producing the melanin-concentrating hormone (MCH) precursor. The present results show that our culture conditions (supplemented RPMI 1640, poly-D-lysine substrate) are efficient in promoting attachment and growth of MCH neurons dissociated from rat fetal hypothalamus. These neurons acquire a differentiation stage in which neuropeptides of interest to us are expressed in a pattern similar to that observed on tissue sections: (1) coexpression of salmon MCH, growth-hormone-releasing factor (GRF37), alpha-melanocyte-stimulating hormone and acetylcholinesterase immunoreactivities, and (2) different intracellular distribution of salmon MCH and 1-37 sequence of GRF37 staining. Neurite growth was rapid and interneuronal connections were observed early. These observations suggest that our model of defined medium culture is suitable for functional investigations on MCH neurons.
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PMID:Expression of peptides derived from the melanin-concentrating hormone precursor in serum-free culture of rat fetal hypothalamic neurons: role of attachment factors. 180 58

Friend murine erythroleukemia cells (MELCs) have been reevaluated in terms of their nature and potential pathways of differentiation. MELC induced with 5 mmol/L hexamethylene bisacetamide (HMBA), in addition to expression of known markers of the erythroid phenotype, were also found to exhibit traits of the megakaryocytic lineage. Erythroid differentiation was shown by the typical synthesis and accumulation of hemoglobin (Hb); megakaryoblastoid differentiation of MELCs upon induction was shown by increased specific activity of acetylcholinesterase (AChE). Incubation of MELCs with 5 mmol/L HMBA in RPMI supplemented with 1% fetal calf serum (FCS) (instead of the usual 5%), induced cells to selectively express high levels of AChE (up to approximately 170 mU/mg protein) with little activation of Hb synthesis (less than 5% B+ cells). The increase in AChE levels was a general phenomenon affecting the whole cell population and approached its maximum within 3 days of incubation with the inducer. Subsequently, MELCs become committed to terminal division, undergoing growth arrest and expression of the megakaryocytic phenotype even after the removal of HMBA. There were no appreciable changes of basal AChE levels in MELCs that were either made resistant to HMBA or treated with 0.1 mmol/L hemin that activated differentiated erythroid function without commitment. Phorbol 12-myristate 13-acetate (PMA), known to repress induced Hb synthesis in these cells, did not prevent the full increase in AChE when incubated with MELCs 2 days before HMBA addition. HMBA-induced MELCs always underwent AChE increase that was more or less pronounced depending on the low or high serum content in culture, respectively. Conversely, Hb expression was permitted only when MELCs were transferred in the late phase or at the end of commitment from low to high serum media. Variations of FCS content in culture media proved to be a simple and reliable approach to change the MELC response to inducers and to modulate expression of either megakaryocytic or mixed erythromegakaryocytic phenotype. These findings suggested that MELC might be considered, at least, as a bipotential model of differentiation to be used for studies on regulation of either megakaryocytic or erythroid markers and on competition between the two hematopoietic lineages. In this regard, it was intriguing that AChE levels attained under selective induction (low serum) were always higher than under conditions allowing coexpression of both AChE and Hb (high serum). Moreover, MELCs were also found to bind the specific rat-antimouse platelet monoclonal antibody 4A5.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Identification and conditions for selective expression of megakaryocytic markers in Friend erythroleukemia cells. 767 Jan 6

The secretion of acetylcholinesterase (AChE) by female and male Heligmosomoides polygyrus was studied in different in vitro culture media. AChE secretion was increased in the presence of fetal calf serum or bovine serum albumin (BSA). In the absence of crowding effects, specific AChE activity in excretion/secretion products was higher for male (2.41 +/- 0.07 mumol min-1 l-1 mg-1) than for female (0.56 +/- 0.04 mumol min-1 mg-1) worms but on a per nematode basis both sexes showed comparable rates of secretion. Acetylthiocholine iodide was the favoured substrate of the enzyme. When the nematodes were incubated in vitro with albendazole (ABZ), ricobendazole (RBZ), mebendazole (MBZ), levamisole (LVM), morantel (MRT) or ivermectin (IVM), at concentrations from 1 mM to 10 nM, in RPMI medium for 2 or 6 h and then transferred to a drug-free medium (RPMI medium supplemented with 0.5% BSA) for 24 h or continuously exposed to the drugs in supplement-free medium (24 h), the concentration- and time-dependent inhibitory effects on AChE secretion were observed. The continued exposure to the drugs for all incubation periods (with a single exception for LVM 1 mM) produced the highest levels of inhibition. Under these conditions, the concentrations inhibiting the secretion of AChE by 50% (IC50) relative to drug-free controls were estimated. The IC50 values ranged from 0.012 microM (IVM) to 2.96 microM (MRT). The potential of this bioassay for the selective primary evaluation of new compounds with broad-spectrum anti-nematodal activity is discussed.
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PMID:The in vitro secretion of acetylcholinesterase by adult stages of Heligmosomoides polygyrus: the effects of broad-spectrum anthelmintics. 1078 Jan 68