Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.1.53 (sialidase)
 2,694 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A battery of horseradish peroxidase-conjugated lectins (Con A, WGA and DBA), as well as conventional histochemical techniques (PAS, saponification, Alcian Blue pH 0.1, 1, 2.5, chlorhydric hydrolisis, sialidase, Bromophenol blue, Tioglycollate reduction and Ferric-ferricyanide-FeIII) were used to study the content and distribution of carbohydrates, proteins and glycoconjugate sugar residues on the skin and on the lymphocystis-infected cells of gilthead seabream, Sparus aurata. Variable amounts of glycoproteins containing sialic acid, N-acetyl-D-glucosamine, N-acetyl-D-galactosamine, mannose and/or glucose residues were observed in the cuticle and mucous cells of the corporal skin, tails and fins. Germinative and epithelial cells of the epidermis contained glycogen, proteins, carboxylated groups, as well as glycoproteins with mannose and/or glucose and N-acetyl-D-galactosamine residues. Hyaline capsule of the mature lymphocystis-infected cells was strongly stained with PAS, Alcian Blue (pH 0.5 and 2.5) and weakly positive with Alcian Blue (pH 1). Con A reacted with the granular cytoplasm, specially around hyaline capsule, and with the basophilic intracytoplasmic inclusions developed in mature lymphocystis-infected cells of Sparus aurata skin. These sugar residues (mannose and/or glucose), as well as N-acetyl-D-glucosamine and/or sialic acid and N-acetyl-D-galactosamine were not detected in the hyaline capsule of the lymphocystis disease.
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PMID:Histochemical study of lymphocystis disease in skin of gilthead seabream, Sparus aurata L. 947 32

We examined a patient with adult onset sialidosis using N-isopropyl-p-123I-iodoamphetamine single photon emission computed tomography (SPECT) and 18F-2-fluoro-2-deoxy-D-glucose positron emission tomography (PET). A 41-year-old [correction of 47] man was admitted to our hospital because of the involuntary movement of his extremities and gait disturbance. On admission, he exhibited action myoclonus in his face and extremities with cerebellar ataxia. Ophthalmoscopy revealed cherry-red spots on his retina. Enzymological analysis of his leucocytes and skin fibroblasts revealed primary sialidase deficit. Brain MRI showed no abnormal findings. Brain SPECT showed decreased cerebral blood flow in the cortex of bilateral occipital lobes, and PET study revealed decreased glucose metabolism in the cortex of bilateral occipital lobes. This case is the thirteenth patient of adult onset sialidosis in Japan. As far as we know, there are no previous reports of SPECT or PET on sialidosis patients. Why the cerebral blood flow and glucose metabolism was decreased in the occipital lobe region remains obscure. From the literatures, we suppose that the onset time of neuronal tissue degeneration or the sensitivity to cumulative metabolites in the occipital region may be different from those in other regions. Further studies are required to confirm abnormalities of cerebral blood flow and metabolism in sialidosis.
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PMID:[Neuroradiological findings on cerebral blood flow and metabolism of a case of adult onset sialidosis]. 950 67

Various aryl and alkyl alpha-glycosides of KDN were synthesized and tested as substrates for their susceptibility to a deaminoneuraminic acid (KDN)-specific sialidase from Sphingobacterium multivorum, designated KDNase Sm. The synthetic KDN-glycosides were all hydrolyzed by the action of KDNase Sm. A hydroxyl group at C-5 position of KDN was required for the recognition by the enzyme, and was shown not to be replaced by an amino- or an acylamino group for the enzymatic recognition. These synthetic KDN-glycosides were also examined for their inducing activity of KDNase in S. multivorum and were shown to induce the KDNase activity effectively when the bacterium was cultured minimum salt medium containing both 0.1% glucose and 0.1% various KDN-glycosides. No KDNase activity was induced by the KDN-glycosides without 0.1% glucose. This is the first case of using synthetic KDN-glycosides as inducers of KDNase Sm.
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PMID:Induction of KDNase Sm, a deaminoneuraminic acid (KDN) residue-specific sialidase from Sphingobacterium multivorum, using synthetic KDN-glycosides. 970 55

African trypanosomes have been shown previously to undergo efficient transformation from bloodstream forms to procyclic (insect dwelling) forms in vitro by adding citrate and/or cis-aconitate to the culture medium and lowering incubation temperature to 27 degrees C. In this paper, it is shown that strain 427 monomorphic bloodstream forms of Trypanosoma brucei grown in axenic culture at 37 degrees C can be transformed to procyclic forms by simply replacing the glucose carbon source in the culture medium with glycerol. The removal of glucose from the medium results in the loss of the variant surface glycoprotein, the acquisition of cell surface procyclic acidic repetitive protein, the synthesis of procyclic-specific glycosylphosphatidylinositol precursors and the acquisition of substantial resistance to salicyl hydroxamic acid and glycerol within 72 h. A procyclic-specific cytoskeletal protein, known to be a marker of the late stage of transformation, is fully expressed by 96 h but full trans-sialidase activity appears only after 18-30 days. The transformation process described here is slower and less efficient than that previously described for monomorphic trypanosomes, using citrate and/or cis-aconitate and temperature shift as triggers. However, the separation of the transformation process from these stimuli is significant and the effects of glucose deprivation described here may reflect some of the events that occur in vivo in the tsetse fly midgut, where glucose levels are known to be very low.
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PMID:Transformation of monomorphic Trypanosoma brucei bloodstream form trypomastigotes into procyclic forms at 37 degrees C by removing glucose from the culture medium. 971 13

A hemagglutinin was purified from the cotyledons of Japanese chestnut (Castanea crenata Sieb. et Zucc.) by affinity chromatography on asialo-fetuin Sepharose 4B column followed by anion-exchange and gel permeation chromatography. The hemagglutinating activity of Castenea crenate agglutinin (CCA) was strong for sialidase-treated human erythrocytes, but was inhibited by mannose, glucose, and their derivatives as well as by glycoproteins having an N-linked complex carbohydrate type. The apparent M(r) of intact CCA was determined to be ca 257,000 by gel filtration using a Superose 12 column. In SDS-PAGE, under reducing and non-reducing conditions, CCA migrated as a single band of M(r) 37,000. Therefore, the intact CCA may be composed of six or eight identical subunits without disulfide bonds. In addition, CCA showed strong mitogenic activity similar to other lectins. The N-terminal amino acid of CCA may be blocked since no amino acid was detected by direct sequence analysis. Amino acid analysis showed that CCA was rich in glycine, but did not contain cysteine residues. Some properties of CCA were similar to mannose/glucose-specific legume lectins, but our data suggest that the molecular structure of CCA is different.
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PMID:Purification and characterization of a mannose/glucose-specific lectin from Castanea crenata. 977 92

The inhibitory effects of various sulfated compounds on the activities of sialidases purified from porcine liver and human placenta were investigated. Among the sulfated compounds tested, heparin, dextran sulfate, condroitin sulfates and sulfatide significantly inhibited the 4-methylumbelliferyl-alpha-N-acetylneuraminic acid (4-MU-NeuAc) sialidase activities of the two enzyme preparations, but glucose 6-sulfate and glucosamine 6-sulfate did not. Potassium sulfate showed an inhibitory effect only at high concentrations. When the sialidase activities were measured using natural substrates, the sialidase activities for the (alpha2-3) and (alpha2-6) sialyllactoses, and colominic acid, were markedly inhibited by heparin and sulfatide similar to 4-MU-NeuAc, although the fetuin sialidase activity was not significantly influenced by them. The sialidase activity hydrolyzing GM3 was strongly inhibited by heparin, but not by sulfatide.
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PMID:Effect of sulfated compounds on acid sialidase. 985

Clostridium perfringens can obtain sialic acid from host tissues by the activity of sialidase enzymes on sialoglycoconjugates. After sialic acid is transported into the cell, sialic acid lyase (NanA) then catalyzes the hydrolysis of sialic acid into pyruvate and N-acetylmannosamine. The latter is converted for use as a biosynthetic intermediate or carbohydrate source in a pathway including an epimerase (NanE) that converts N-acetylmannosamine-6-phosphate to N-acetylglucosamine-6-phosphate. A 4.0-kb DNA fragment from C. perfringens NCTC 8798 that contains the nanE and nanA genes has been cloned. The identification of the nanA gene product as sialic acid lyase was confirmed by overexpressing the gene and measuring sialic acid lyase activity in a nanA Escherichia coli strain, EV78. The nanA gene product was also shown to restore growth to EV78 in minimal medium with sialic acid as the sole carbon source. By using Northern blot experiments, it was demonstrated that the nanE and nanA genes comprise an operon and that transcription of the operon in C. perfringens is inducible by the addition of sialic acid to the growth medium. The Northern blot experiments also showed that there is no catabolite repression of nanE-nanA transcription by glucose. With a plasmid construct containing a promoterless cpe-gusA gene fusion, in which beta-glucuronidase activity indicated that the gusA gene acted as a reporter for transcription, a promoter was localized to the region upstream of the nanE gene. Primer extension experiments then allowed us to identify a sialic acid-inducible promoter located 30 bp upstream of the nanE coding sequence.
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PMID:Cloning, sequence, and transcriptional regulation of the operon encoding a putative N-acetylmannosamine-6-phosphate epimerase (nanE) and sialic acid lyase (nanA) in Clostridium perfringens. 1041 49

The effect of ammonium chloride was determined on a culture of CHO cells transfected with the human erythropoietin (EPO) gene. Cell growth was inhibited above a culture concentration of 5 mM NH(4)Cl with an IC-50 determined to be 33 mM. The specific production of EPO increased with the addition of NH(4)Cl above 5 mM. At 10 mM NH(4)Cl, the final cell density after 4 days in culture was significantly lower but the final yield of EPO was significantly higher. This appeared to be due to continued protein production after cell growth had ceased. The metabolic effects of added NH(4)Cl included higher specific consumption rates of glucose and glutamine and an increased rate of production of alanine, glycine, and glutamate. The EPO analyzed from control cultures had a molecular weight range of 33-39 kDa and an isoelectric point range of 4.06-4.67. Seven distinct isoforms of the molecule were identified by two-dimensional electrophoresis. This molecular heterogeneity was ascribed to variable glycosylation. Complete enzymatic de-glycosylation resulted in a single molecular form with a molecular mass of 18 kDa. Addition of NH(4)Cl to the cultures caused a significant increase in the heterogeneity of the glycoforms as shown by an increased molecular weight and pI range. Enzymatic de-sialylation of the EPO from the ammonia-treated and control cultures resulted in identical electrophoretic patterns. This indicated that the effect of ammonia was in the reduction of terminal sialylation of the glycan structures which accounted for the increased pI. Selective removal of the N-glycan structures by PNGase F resulted in two bands identified as the O-glycan linked structure (19 kDa) and the completely de-glycosylated structure (18 kDa). The proportion of the O-linked glycan structure was reduced, and its pI increased in cultures to which ammonia was added. Thus, the glycosylation pattern altered by the presence of ammonia included a reduction in terminal sialylation of all the glycans and a reduction in the content of the O-linked glycan. The addition of a sialidase inhibitor to the cultures had no effect on the ammonia-induced increase in EPO heterogeneity. Also, the effect of ammonia on glycosylation could not be mimicked using the weak base chloroquine in our system.
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PMID:Effects of ammonia on CHO cell growth, erythropoietin production, and glycosylation. 1074 5

Quantitative data are presented on the influences of hyper-gravity (3 +/- 1g) and of simulated weightlessness (approximately 0g) during early ontogeny of cichlid fish (Oreochromis mossambicus) and clawed toad (Xenopus laevis, Daudin) demonstrating changes in the swimming behaviour and the brain energy and plasma membrane metabolism. After return to 1g conditions, hyper-g reared fish and toads express the well known "loop-swimming" behaviour. By means of a computer based video analyzing system different types of swimming movements and velocities were quantitatively determined. Analyses of the brain energy and plasma-membrane metabolism of hyper-g fish larvae demonstrated an increase in energy availability (glucose 6Pi dehydrogenase, G-6P-DH), a decrease of cellular energy transformation (creatine kinase activity, CK) but no changes in energy consumptive processes (e.g. ATPases) and cytochrome oxidase activity (Cyt.-Ox). In contrast hypo-g fish larvae showed a slight increase in brain CK activity. In addition, unlike 1g controls, hyper-g fish larvae showed pronounced variations in the composition (=polarity) of sialoglycosphingolipids (=gangliosides), typical constituents of the nerve cell membranes, and a slight increase in the activity of sialidase, the enzyme responsible for ganglioside degradation.
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PMID:Behavioural and biochemical investigations of the influence of altered gravity on the CNS of aquatic vertebrates during ontogeny. 1153 32

Sialidase from Entamoeba histolytica was purified to apparent electrophoretic homogeneity by chromatography on hydroxyapatite, reactive brown agarose, fetuin/agarose and by fast performance liquid chromatography on a MonoQ column. The enzyme had a molecular mass of 65 kDa, as determined by SDS-PAGE. It had an optimum pH of 5.5 and was maximally active at 37 degrees C. It required Ca(2+) and Mg(2+) for activation but was strongly inhibited by Cu(2+), Fe(2+) and Zn(2+). The E. histolytica sialidase exhibited high specificity for Neu5Acalpha2,3lac and methylumbelliferyl-Neu5Ac (4-MU-Neu5Ac) with K(m) values of 0.144 mM and 0.059 mM, respectively. The enzyme was not active against colomic acid and the gangliosides GM(1) and GD(1). It was activated in the presence of lactose and galactose, but was unaffected by glucose, sucrose and mannose. The enzyme was inhibited competitively by 2,3,didehydroneuraminic acid and para-nitro-phenyloxamic acid with inhibition binding constants ( K(i)) of 30 micro M and 185 micro M, respectively. The motility of intact E. hystolytica cells was enhanced about 6-fold in the presence of 0.05-0.1 mM Neu5Acalpha2,3lac, 4-MU-Neu5Ac and fetuin. However, the motility of the parasite was highly diminished when incubated with Neu5Acalpha2en and sialic acid-containing compounds. Lysed E. histolytica trophozoites were found to lack neuraminic acid.
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PMID:Characterization of sialidase from Entamoaeba hystolitica and possible pathogenic role in amebiasis. 1263 68


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