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)

Conley et al., in 1971, described a special type of melanoma characterized by a superficial melanic lesion at the onset; repeated local relapses as subcutaneous tumorations with an histological picture closely resembling an atypical fibroxantoma or fibrosarcoma. After a review of all the published material the autors presents a personal case with the clinical, histological and evolutive characteristics of this disease. The most interesting findings of the published case are the following: The special stains for the melanocytes (silver stain, Dopa, tyrosinase and cholinesterase) were all negative. There was an intense positivity for the lisosomal enzymes (non specific sterases, and acid phosphatases). The ultrastructural study of the tumoral tissues as well as the cells of cultures showed abundant cells with tumoral aspects, with prominent nucleoli somewhat dilated granular endoplasmic reticulum, myelin-like figures, lipidic vacuoles and abundant lisosomes. No melanosomes or premelanosomes were observed. Beside these tumoral cells abundant typical fibroblastic elements were found. There was a great amount of collagen fibers with periodicity superior to the normal. The conclusion is that the desmoplastic melanoma must be considered as a tumor of mesenchimatous origin intervening in its development multiple local and general factors.
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PMID:[Desmoplastic melanoma]. 34 19

The dermal cells in grey, xanthic, and white goldfish integuments were cytochemically characterized for the following enzymatic activities: tyrosinase, DOPA-oxidase, cytochrome oxidase, monoamine oxidase, peroxidase, non-specific esterase, cholinesterase, NAD-diaphorase, NADP-diaphorase, aryl sulfatase, nucleotide phosphodiesterase, beta-glucuronidase, acid phosphatase, alkaline phosphatase, adenosine triphosphatase, thiamine pyrophosphatase, glucose-6-phosphatase, aldolase, as well as succinate, malate, isocitrate, glutamate, glucose-6-phosphate, 6-phosphogluconate, alpha-glycerophosphate, alcohol, lactate, and beta-hydroxybutyrate dehydrogenases. It was found that the epidermis was a significant barrier to the access of cytochemical reaction substrates. Removal of the epidermal barrier provided dermal cell localizations of enzymatic activities which were reproducible. Further, alterations in reaction times and temperatures from the mammalian methodology provided conditions fe various integumental cells were compared for possible interrelationships. The basic foundations for future work with the dermis of poikilothermic vertebrates on an experimental basis were established. In addition, a previously undescribed non-pigmented dermal cell, the "x"-cell, was found to have enzymatic characteristics similar to both melanophores and lipophores. The "x"-cell may be the common precursor of both types of pigment cells.
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PMID:Cytochemical characterization of goldfish (Carassius auratus L.) dermis with special reference to the pigment cells. 82 86

Anural development in the ascidian Molgula occulta was examined using tissue-specific markers and interspecific hybridization. Unlike most ascidians, which develop into a swimming tadpole larva (urodele development), M. occulta eggs develop into a tailless slug-like larva (anural development) which metamorphoses into an adult. M. occulta embryos show conventional early cleavage patterns, gastrulation, and neurulation, but then diverge from the urodele developmental mode during larval morphogenesis. M. occulta larvae do not contain a pigmented sensory cell in their brain or form a tail with differentiated notochord and muscle cells. As shown by in situ hybridization with cloned probes and analysis of in vitro translation products, M. occulta embryos do not accumulate high levels of alpha actin or myosin heavy chain mRNA. In contrast, acetylcholinesterase is expressed in muscle lineage cells, indicating that various muscle cell features are differentially suppressed. M. occulta embryos also lack tyrosinase activity, suggesting that suppression of brain pigment cell differentiation occurs at an early step in development. M. occulta eggs fertilized with sperm from Molgula oculata (a closely related urodele species) develop into hybrid larvae exhibiting some of the missing urodele features. Some hybrid embryos develop tyrosinase activity and differentiate a brain pigment cell and a short row of notochord cells, and form a short tail. These urodele features appeared together or separately in different hybrid embryos suggesting that they develop by independent mechanisms. In contrast, alpha actin and myosin heavy chain mRNA accumulation was not enhanced in hybrid embryos. These results suggest that multiple mechanisms control anural development.
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PMID:Interspecific hybridization between an anural and urodele ascidian: differential expression of urodele features suggests multiple mechanisms control anural development. 212 92

The effect of ultraviolet (uv) light on embryonic development was examined in the ascidian Styela clava. uv irradiation (3.0 x 10(-3) J mm-2) of the entire surface of fertilized eggs during ooplasmic segregation prevented gastrulation, sensory cell induction, and embryonic axis formation. The uv-irradiated embryos completed ooplasmic segregation and cleaved normally, but vegetal blastomeres did not invaginate at the beginning of gastrulation, sensory cells in the larval brain did not develop tyrosinase or melanin pigment, and the larval tail did not develop. Endoderm, epidermis, and muscle cells differentiated in the uv-irradiated embryos, however, as evidenced by expression of endodermal alkaline phosphatase (AP), an epidermal-specific antigen, and alpha-actin, myosin heavy chain, and acetylcholinesterase (AChE) in muscle cells. Higher doses of uv light (6.0-9.0 x 10(-3) J mm-2) suppressed expression of the epidermal antigen and muscle cell markers, whereas the development of endodermal AP was insensitive. Irradiation at various times between fertilization and the 16-cell stage revealed that gastrulation, sensory cell differentiation, and axis formation are sensitive to uv light only during ooplasmic segregation. Irradiation of restricted regions of the zygote during ooplasmic segregation showed that the uv-sensitive components are localized in the vegetal hemisphere. The absorption characteristics of the uv-sensitive components suggest that they are nucleic acids. The results show that uv-sensitive components that specify gastrulation, sensory cell induction, and embryonic axis formation are localized in the vegetal hemisphere of Styela eggs.
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PMID:Ultraviolet irradiation during ooplasmic segregation prevents gastrulation, sensory cell induction, and axis formation in the ascidian embryo. 237 59

In order to clarify the histogenesis of clear cell sarcoma of tendons and aponeuroses (CCS), two cases of human and one nude mouse-transplanted CCS line were studied using an ultrastructural and enzyme cytochemical approach. Most of the tumour cells obtained from the primary and transplanted CCS demonstrated melanosomes in various stages of development within the cytoplasm, whereas no melanosomes could be identified in the metastatic CCS. However, cholinesterase and tyrosinase activities could be demonstrated not only in the melanotic primary and transplanted CCS but also in the amelanotic metastatic CCS. The results therefore support the hypothesis that CCS is a soft tissue tumour derived from the neural crest.
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PMID:Neural crest origin of clear cell sarcoma of tendons and aponeuroses. Ultrastructural and enzyme cytochemical study of human and nude mouse-transplanted tumours. 249 78

Cleavage-arrested embryos of the ascidian Ciona intestinalis were able to differentiate two tissue-specific enzymes-muscle acetylcholinesterase (EC 3.1.1.7) and brain pigment cell tyrosinase (EC 1.10.3.1). Cytochalasin B, colchicine, Colcemid, and podophyllotoxin were used as cleavage inhibitors at early embryonic stages up to the 64-cell stage. Only certain cells in the cleavage-arrested embryos developed these histochemically detectable enzymes, and this ability followed the cell lineage patterns for the two tissues. This result implies the presence of specific positional information in the egg cytoplasm that is differentially segregated during cleavage. There were distinct and separate puromycin and actinomycin D sensitivity periods for the occurrence of each enzyme during development of both normal and cleavage-arrested embryos. The segregated information is apparently neither the enzyme proteins nor RNA templates for enzyme synthesis, but is probably concerned with activation of appropriate genes.
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PMID:Segregation during ascidian embryogenesis of egg cytoplasmic information for tissue-specific enzyme development. 419 63

Molgula tectiformis is a new ascidian species recently described by Nishikawa (1991). In Otsuchi Bay, Iwate, Japan, they are easily obtainable from cages for culturing scallops. We report here that M. tectiformis is another example of a direct developer: their embryonic development is lacking the tadpole larva. The fertilized egg is orange and about 150 microns in diameter. At 18 degrees C, the egg cleaves at about 20 min intervals and gastrulation occurs about 5 hr after fertilization. In contrast to conventionally-developing ascidians, M. tectiformis does not form a tadpole larva. Immediately before hatching, three stolons or ampullae begin to extend from the tailless embryo. After hatching the stolons mediate the attachment of the juvenile body to the substratum. Histochemistry for tissue-specific enzyme activity did not detect muscle-specific acetyl-cholinesterase, endoderm-specific alkaline phosphatase, and pigment cell-specific tyrosinase. In addition, in situ hybridization could not prove the presence of muscle actin gene transcripts in the embryo. These results suggest that these larval tissues do not differentiate in M. tectiformis embryos. Because M. tectiformis is common and gravid year-around in Otsuchi Bay, this direct developer provides the opportunity for further analysis of molecular changes during evolution that cause an alternative mode of development.
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PMID:The recently-described ascidian species Molgula tectiformis is a direct developer. 925 52

Two-enzyme systems based on acetylcholinesterase (AChE) - a mono-enzyme system based on AChE, with p-aminophenyl acetate as substrate, and a bi-enzyme system based on AChE and tyrosinase, with phenyl acetate as substrate - have been studied for detection of organophosphate insecticides. The analytical performance and detection limits for determination of the pesticides were compared for the two AChE configurations. The enzyme loading, pH, and applied potential of the bi-enzyme system were optimised. When phenyl acetate was used as substrate for AChE activity the phenol generated by enzymatic hydrolysis was determined with a second enzyme, tyrosinase. Amperometric measurements were performed at 100 mV and -150 mV relative to the Ag/AgCl reference electrode for the mono-enzyme and bi-enzyme systems. Screen-printed sensors were used to detect the organophosphorus pesticides paraoxon and chlorpyrifos ethyl oxon; the detection limits achieved with phenyl acetate as substrate were 5.2x10(-3) mg L(-1) and 0.56x10(-3) mg L(-1), respectively.
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PMID:Detection of organophosphorus insecticides with immobilized acetylcholinesterase - comparative study of two enzyme sensors. 1220 38

Screen-printing technology for electrode fabrication enables construction of amperometric devices suitable for combination of several enzyme electrodes. To develop a biosensor array for characterisation of wastewaters, tyrosinase and horseradish peroxidase (HRP) or cholinesterase-modified electrodes were combined on the same array. The behaviour of the tyrosinase-modified electrode in the presence of hydrogen peroxide (required co-substrate for the HRP-modified electrode) and acetylthiocholine chloride (required co-substrate for cholinesterase) was studied. Performance of bi-enzyme biosensor arrays in the batch mode and in the flow-injection system are discussed.
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PMID:Screen-printed multienzyme arrays for use in amperometric batch and flow systems. 1285 95

Four wastewater samples of different treatment qualities; untreated, alarm, alert and normal, from a Swedish chemi-thermo-mechanical pulp mill and pure water were investigated using an amperometric bio-electronic tongue in a batch cell. The aim was to explore enzymatically modified screen-printed amperometric sensors for the discrimination of wastewater quality and to counteract the inherent drift. Seven out of eight platinum electrodes on the array were modified with four different enzymes; tyrosinase, horseradish peroxidase, acetyl cholinesterase and butyryl cholinesterase. At a constant potential the current intensity on each sensor was measured for 200s, 100s before injection and 100s after injection of the sample. The dynamic biosensor response curves from the eight sensors were used for principal component analysis (PCA). A simple baseline and sensitivity correction equivalent to multiplicative drift correction (MDC), using steady state intensities of reference sample (catechol) recordings, was employed. A clear pattern emerged in perfect agreement with prior knowledge of the samples explaining 97% of the variation in the data by two principal components (PCs). The first PC described the treatment quality of the samples and the second PC described the difference between treated and untreated samples. Horseradish peroxidase and pure platinum sensors were found to be the determinant sensors, while the rest did not contribute much to the discrimination. The wastewater samples were characterized by the chemical oxygen demand (COD), biological oxygen demand (BOD), total organic carbon (TOC), inhibition of nitrification, inhibition of respiration and toxicity towards Vibrio fischeri using Microtox, the freshwater alga Pseudokirchneriella subcapita and the freshwater crustacean Daphnia magna.
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PMID:Chemometric exploration of an amperometric biosensor array for fast determination of wastewater quality. 1620 74


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