The presence of galactofuranose and ribose units in asparagine-linked oligosaccharides of the digenetic trypanosomatid Endotrypanum schaudinni.

It was found that the digenetic trypanosomatid Endotrypanum schaudinni transferred Man7GlcNAc2 in protein N-glycosylation. Endo-beta-N-acetylglucosaminidase H-sensitive oligosaccharides were identified as Man7GlcNAc2, Man6GlcNAc2, Rib1Man6GlcNAc2 and/or Gal1Man6GlcNAc2, Man5GlcNAc containing two galactose or ribose units or one of each residues, Rib1Man5GlcNAc2 and Gal1Man5GlcNAc2. The galactoses were in the furanose configuration. Endo-beta-N-acetylglucosaminidase H-resistant glycopeptides that were retained by concanavalin A-Sepharose and eluted with alpha-methylmannoside were found to contain mannose, galactofuranose and ribose units. The presence of galactofuranoses in N-glycoproteins has been reported previously in several monogenetic trypanosomatids but only in one digenetic parasite (Trypanosoma cruzi). This and a recent publication on the structure of Blastocrithidia culicis N-linked oligosaccharides are the first reports on the presence of ribose in eukaryotic glycoconjugates.

Characterization and partial purification of a novel enzymatic activity. UDP-GlcNAc:Ser-protein N-acetylglucosamine-1-phosphotransferase from the cellular slime mold Dictyostelium discoideum.

An enzymatic activity that transfers N-acetylglucosamine-1-phosphate residues from UDP-GlcNAc to serine units in proteins (UDP-GlcNAc:Ser-protein N-acetylglucosamine-1-phosphotransferase) was detected in membranes of the cellular slime mold Dictyostelium discoideum. The enzyme was partially purified by affinity chromatography in concanavalin A-Sepharose and ion exchange chromatography in a Mono Q column. The enzyme showed an absolute requirement for bivalent cations, Mn2+ being more effective than Mg2+. It had a broad optimum pH value (6.5-9.0). The Km for UDP-GlcNAc was 18 microM. In cell free assays it used apomucin and native or 8 M urea-denatured thyroglobulin but neither bovine serum albumin nor native or denatured uteroferrin as exogenous acceptors. Analysis of proteins isolated from cells grown in the presence of [32P]phosphate and from the culture medium showed that the majority of proteins bearing the structure Glc-NAc-1-P-Ser were secreted. In equilibrium density centrifugations of microsomes, the enzyme appeared in membranes having lighter densities than the enzyme that phosphorylates high mannose-type oligosaccharides. This showed that the activity that phosphorylates serine residues in proteins (UDP-GlcNAc:Ser-protein N-acetylglucosamine-1-phosphotransferase) is different from that phosphorylating protein-linked high mannose-type oligosaccharides (UDP-GlcNAc:glycoprotein N-acetylglucosamine-1-phosphotransferase).

Novel (rhamnosyl and ribosyl) and uncommon (xylosyl) monosaccharide residues are present in asparagine-linked oligosaccharides of the trypanosomatid Blastocrithidia culicis.

Blastocrithidia culicis is a trypanosomatid protozoon that transfers Man6GlcNAc2 in protein N-glycosylation. Compounds containing mannosyl, xylosyl, and rhamnosyl residues were found among the endo-beta-N-acetylglucosaminidase H-sensitive oligosaccharides of whole cell glycoproteins of this parasite. The compositions of some of them were as follows: Man5GlcNAc2, Man6GlcNAc2, Rha1Man5GlcNAc2, Rha2Man6GlcNAc2, Xyl1Rha2Man6-GlcNAc2, Xyl1Rha3Man6GlcNAc2, and Xyl2Rha3Man6-GlcNAc2. On the other hand, oligosaccharides containing mannosyl, xylosyl, rhamnosyl, and ribosyl units were liberated from endo-beta-N-acetylglucosaminidase-resistant glycopeptides upon treatment with N-glycanase. This is the first report on the presence of ribosyl units in eukaryote glycoconjugates, of rhamnosyl residues in asparagine-linked oligosaccharides, and of xylosyl units in high mannose-type compounds.

The presence in Trypanosoma cruzi microsomes of alpha(1,2), alpha(1,3) and alpha(1,6) mannosidase activities not involved in protein-linked Man9GlcNAc2 processing.

Trypanosoma cruzi microsomes were found to possess membrane-bound alpha(1,2), alpha(1,3) and alpha(1,6) mannosidase activities that had an almost neutral optimum pH value, did not require CaCl2 for activity and were inhibited by swainsonine but not by deoxymannojirimycin. A mannosidase activity that degraded p-nitrophenylmannoside and that was inhibited by swainsonine was also present in the parasite microsomes. Experiments performed with intact cells showed that processing of protein-linked Man9GlcNAc2 was inhibited by deoxymannojirimycin but not by swainsonine. It was concluded that the activities detected were not involved in protein-linked Man9GlcNAc2 processing.

P300 and CT scan in patients with chronic schizophrenia.

Twenty chronic male schizophrenic subjects aged 30-50 years were examined by an auditory event-related potential procedure for the evaluation of the P300 component, a CT scan and a neuropsychological test battery. The P300 latency was increased and its amplitude was reduced. CT scan measures showed lateral and third ventricle enlargement, and there was a global neuropsychological impairment. Poor neuropsychological performances were consistently associated with delayed P300 latencies, but not with CT scan measures. Ventricular enlargement was more pronounced among subjects with a negative family history for major psychiatric disorders.

Tourettism as clinical presentation of Huntington's disease with onset in childhood.

Infantile Huntington's disease (HD) shows a wide clinical heterogeneity. Here we describe the case of a child affected by HD who showed unusual neurological features consistent with tourettism. The absence of family history and persisting normal magnetic resonance imaging (MRI) results long after the onset of symptoms delayed the diagnosis of the disease. An MRI exam performed 26 months after disease onset disclosed bilateral atrophy in the putamen, suggesting HD. The diagnosis was confirmed by genetic analysis. The present report underlines the need to consider HD in childhood cases of unusual and even unfamiliar progressive movement disorders.

Affinity sites for N-acetyl-beta-D-glucosaminidase on the surface of rat epididymal spermatozoa.

The binding of N-acetyl-beta-D-glucosaminidase from rat epididymal fluid to the surface of spermatozoa from the cauda epididymis was measured in the presence of sugars, its phosphorylated derivatives, or after treatment of the cells or the enzyme with agents that alter the integrity of proteins or carbohydrates. The binding was saturable, with a Kd in the nanomolar range, was inhibited with phosphorylated derivates of fructose, and did not depend on Ca2+, showing that it is different from the mannose 6-P-recognizing system existing in other tissues for this and other acid hydrolases. Treatment of the cells with sodium periodate or trypsin inhibited the binding, showing that a glycoprotein of the plasmalemma is involved in the affinity site. Fructose or phosphorylated derivates were not detected in the proteins of the epididymal fluid with HPLC. However, with the method used, the presence of these compounds cannot be ruled out, if among the proteins of the fluid there are only a small number of acid hydrolases containing this sugar.