Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.4.37 (CNPase)
 539 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We describe a simple, rapid, and efficient method, based on separation on a Percoll centrifugation gradient, to purify glial progenitor cells from newborn rat brains. Cytofluorimetry analysis of the isolated cell population showed that 75 +/- 8 and 86 +/- 7% of the cells were A2B5- and R24-positive, respectively. Transmission electron microscopy examination of the purified cell population confirmed their homogeneity and illustrated their typical morphology, as previously described in situ. Assay of UDP-galactose-ceramide galactosyltransferase, 3'-phosphoadenosine 5'-phosphosulfate galactosylceramide sulfotransferase, and 2',3'-cyclic nucleotide 3'-phosphohydrolase activities showed that the levels of these enzymes were 446, 76, and 11 times lower, respectively, than the levels measured in mature oligodendrocytes. Low levels of mRNA coding for 2',3'-cyclic nucleotide 3'-phosphohydrolase and myelin proteolipid protein, but not for myelin basic protein, were present in the glial progenitor cells. At the time of isolation, 40% of the cells in the population were dividing, and the cells could easily be expanded in culture. After 3 weeks of culture in the presence of 1% fetal calf serum, 75% of the cells had differentiated into galactosylceramide-positive oligodendrocytes. When the culture took place in the presence of 10% fetal calf serum, only 2% of the cells expressed galactosylceramide, and 60% were glial fibrillary acidic protein-positive astrocytes; half of them were also A2B5 positive.
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PMID:Morphological, biochemical, and functional characterization of bulk isolated glial progenitor cells. 170 21

Oligodendroglia growth factor (OGF) is a 16-kDa soluble protein produced by neuronal cell lines. This factor, when incubated with brain glia in culture, selectively stimulates growth of oligodendroglia, the myelin-producing cells of the CNS. OGF infused into the cerebral cortex of the adult rat accelerates the production of myelin proteins as shown by increased specific activity of the myelin enzyme 2',3'-cyclic nucleotide 3'-phosphohydrolase (2',3'-CNPase), by stimulated synthesis of myelin basic protein, and by elevations in levels of myelin proteolipid protein RNA. The ability of OGF to induce myelin protein production in vivo suggests that neuron-secreted growth factors help to regulate myelin formation within the CNS.
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PMID:A growth factor from neuronal cell lines stimulates myelin protein synthesis in mammalian brain. 170 52

Investigations were carried out on the immunosuppressive effect of gramicidin S (GrS), a cyclic peptide antibiotic produced by Bacillus brevis, on the onset of experimental ocular neuritis and allergic encephalomyelitis in Lewis rats immunized with rat brain homogenates. The criteria for evaluation of the drug effect were changes in body weight, activity of 2',3'-cyclic nucleotide 3'-phosphohydrolase (CNPase), clinical manifestations such as paralysis of lower extremities and histopathological changes. Clinical symptoms and body weight reduction were effectively prevented by GrS treatment of immunized animals. The activity of the myelin marker enzyme CNPase was markedly decreased in the lumbar spinal cord of encephalitogen-immunized animals on day 16 (ie 16 days after immunization) and the decrease of enzymatic activity was partially prevented by GrS administration. On the other hand, the CNPase activity of the retrobulbar optic nerve of inoculated animals remained essentially the same as that of healthy control animals, although inflammatory changes were prominent in the optic nerve. Histopathological changes observed in the optic nerve and spinal cord of diseased animals were virtually absent in GrS-treated animals. A possible mechanism of the immunosuppressive activity of GrS is discussed.
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PMID:Immunosuppressive effect of gramicidin S on experimental ocular neuritis and allergic encephalomyelitis. 170 88

Parallel developmental studies of central nervous system myelin proteins and morphology (postnatal days 15-118; P15-118) confirm qualitative similarities but substantial quantitative differences between homozygous mld mice with Billings-Gagliardi and Wolf's 'USA' versus Matthieu's 'Swiss' genetic backgrounds. The USA mld/mld have fewer convulsions and significantly longer life span. While whole-brain homogenates from both Swiss and USA mld/mld show increases in myelin basic protein (MBP) and in 2',3'-cyclic nucleotide 3'-phosphohydrolase specific activity with age, at P50 and older the levels of both proteins are approximately twice as high in the Swiss. The number of optic nerve axons myelinated is always greater in Swiss mld/mld, and they have approximately twice as many myelin sheaths showing any apposition of cytoplasmic membrane faces (the location of the major dense line in normal myelin), except at the youngest age. Evidence is presented which suggests that these quantitative differences between Swiss and USA mld stocks most likely reflect different regulatory genes influencing the expression of the same (mld) allele, rather than the presence of a different allele at the MBP locus.
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PMID:Quantitative differences between homozygous 'USA' and 'Swiss' mld mutant mice. 171 20

Schwann cells are responsible for the maintenance of the peripheral myelin sheath and neurotoxic insult directed against these cells can result in demyelination with a concomitant loss of neural function. We have utilized several in vitro techniques to investigate the effects of neurotoxins on the complex interactions between SC and axons. SC may be isolated from fresh neonatal sciatic nerves and used to examine the effect of neurotoxins on the axonal membrane induction of SC proliferation and specific myelin protein mRNA expression. We have recently devised a method to obtain SC from frozen sciatic nerves. This method allows pooling of neonatal nerves to generate enough cells for subsequent study. We have also transfected primary Schwann cells with a plasmid containing the large T antigen to obtain a SC line suitable for neurotoxicology studies. The functional status of cultured SC may also be studied via expression of SC specific antigens such as glial fibrillary acidic protein, CNPase, S100, laminin, P0 and myelin basic protein. We also propose culturing SC with dorsal root ganglion neurons to investigate the effect of neurotoxins on all stages of SC maturation, from proliferation to the in vitro synthesis of a compact myelin sheath. These strategies will allow us to investigate the cellular mechanisms of neurotoxicity in the PNS.
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PMID:In vitro use of Schwann cells to elucidate neurotoxic injury. 174 36

The neurochemical effects of maternally administered cadmium (50 ppm through drinking water from 0 day of pregnancy) on the whole brain of offsprings exposed during gestation were studied in 7, 14 and 21 days old rats. The developmental pattern of body weight, protein, DNA and RNA contents in brain were not affected in Cd exposed pups of any age group. Brain weights were significantly reduced in exposed pups of postnatal age of 7 and 14 days but were comparable to controls in 21 days old pups. The content of Cd increased significantly in the brain of gestationally exposed pups of 7 days and remained almost stationary throughout the experimental period. The activity of Acetylcholinesterase, Na+, K(+)-ATPase, CNPase, 5'-Nucleotidase in the brain increased significantly from 7 to 21 days of age in control animals. In experimental pups, the activity of most of the enzymes was almost comparable to controls at 7 days of age except succinate dehydrogenase, which was significantly inhibited at 7, 14 and 21 days compared to controls. The activity of other enzymes was also significantly inhibited in the brain of experimental pups compared to controls of 21 days of age indicating marked retardation in the development of these enzymes. However, these changes had no correlation with the accumulation of Cd in the brain. These studies indicate that in utero exposure to Cd may retard the development of certain neurochemicals which may have long term implications on the brain functions.
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PMID:Gestational cadmium exposure and brain development: a biochemical study. 188 99

This study has dealt with the inhibition by lead of glutamine synthetase (GS) activity in homogenates of mixed glial primary cultures, 95% enriched in differentiating astrocytes. A 70% inhibition was observed with a lead concentration of only 2.5 microM. Prevention of the inhibition by addition of EDTA or dithiothreitol is compatible with the conclusion that the effect is mediated by binding of lead ion to sulfhydryl moieties of the enzyme. Among several other cations tested, only mercury, which has a similarly high binding affinity for sulfhydryl moieties, inhibited the enzyme. The inhibitory effect of lead was relatively specific, since no inhibition of another astrocytic marker enzyme, lactate dehydrogenase, of the oligodendroglial marker enzyme, 2',3'-cyclic nucleotide 3'-phosphohydrolase, or of the plasma membrane marker, Na,Ka-ATPase, was observed with concentrations of lead that produced a 70% decrease of GS. Because of the critical role of GS in regulation of extracellular glutamate, the findings raise the possibility that glutamate-induced neuronal injury is involved in the genesis of the cognitive defects associated with chronic low-level lead exposure in young children.
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PMID:Glutamine synthetase activity of developing astrocytes is inhibited in vitro by very low concentrations of lead. 197 58

Purified Newcastle disease virus (NDV) virions possess 2',3'-cyclic nucleotide 2'-phosphohydrolase (2'-CNPase) and 2',3'-cyclic nucleotide 3'-phosphohydrolase (3'-CNPase) activities. These enzyme activities cannot be removed from the virion even after extensive purification by chromatography on controlled-pore glass. In the intact virion, the 3'-CNPase activity was stimulated by Triton X-100, while the 2'-CNPase activity was partially inhibited. We have prepared the NDV subunits and have shown that 3'-CNPase was associated exclusively with the viral nucleocapsid. In contrast, the 2'-CNPase activity was associated with both the envelope as well as the nucleocapsid. A threshold amount of both enzyme activities was detected in viral M protein.
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PMID:Localization of 2',3'-decycling phosphodiesterases in the Newcastle disease virus virion. 198 76

In a previous paper (Burri et al., 1990), we have shown that experimental hyperphenylalaninemia (hyper-Phe) in 3-17 d-old rats leads to reduced myelinogenesis. Such treated rats recover during a 6 w low phenylalanine (Phe) period between days 17 and 59. In order to get more detailed information about the disturbed myelinogenesis and recovery, we measured in hyper-Phe rats the developmental pattern of two brain enzymes typical for myelination, cerebroside sulfotransferase (CST), and 2',3'-cyclic nucleotide 3'-phosphohydrolase (CNP), and other developmental parameters. Further, we correlated brain Phe levels with the brain damage in hyper-Phe rats, and we measured brain acetylcholinesterase (AChE) as a neuronal marker. Experimental hyper-Phe rats, injected between postnatal days 3 and 17 with alpha-methylphenylalanine and phenylalanine, showed a delayed age-dependent increase of CST activity, compared to that of controls. In hyper-Phe rats, CST peak activity was reached 2-4 d later, and was lower than in controls. The age-dependent decrease of the CST activity, however, started in test and control rats at the same time, at day 21. Between days 24 and 59, hyper-Phe rats had normal CST activity. CNP activity in hyper-Phe rats was lower than in controls from day 10 to 35, and recovered to normal values between days 35 and 59. Our results indicate that recovery from reduced myelinogenesis is possible after the period of fast myelination without compensatory increased CST activity. Further, the brain damage in test rats with Phe levels higher than average is more severe than in test rats with Phe levels lower than average; and there is no effect of hyperphenylalaninemia on brain neurons containing AChE.
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PMID:Reduced myelinogenesis and recovery in hyperphenylalaninemic rats. Correlation between brain phenylalanine levels, characteristic brain enzymes for myelination, and brain development. 209 83

Using an immunoblotting technique, we investigated changes in the concentrations of microtubule-associated protein 2, 200-kDa neurofilament, tubulin, myelin-associated glycoprotein, and 2':3'-cyclic nucleotide 3'-phosphodiesterase in the brains of 40 rats following occlusion of the left middle cerebral artery or sham operation. Compared with those 4 hours after surgery, concentrations of all proteins decreased significantly in the left hemisphere 3 days after surgery (p less than 0.01). Microtubule-associated protein 2 was the most susceptible to ischemia, and its mean +/- SEM concentration decreased to 23 +/- 9.4% of that in concurrent sham-operated controls. Degradation products of microtubule-associated protein 2 and myelin-associated glycoprotein were detected on the blots. Furthermore, in the contralateral hemisphere (where calpain might be activated), concentrations of these two proteins decreased to 57 +/- 12.0% and 83 +/- 4.3% of those in concurrent sham-operated controls, respectively, 3 days after surgery. Changes in the concentrations of cerebral proteins in the contralateral hemisphere are important for understanding clinical symptoms not attributable solely to the ipsilateral lesion following a focal cerebral stroke.
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PMID:Changes in the concentrations of cerebral proteins following occlusion of the middle cerebral artery in rats. 211 75


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