Studies on carbohydrate moieties of the glycoprotein, glucoamylase II of Aspergillus niger: nature of carbohydrate-peptide linkage and structure of oligosaccharides

Electrophoretically homogeneous type 1 (GP-C1 and GP-C2), type 2 (GP-C3a and GP-C3b,) and type 3 (GP-D1, and GP-D2) glycopeptides from Aspergillus niger glucoamylase II (Manjunath and Raghavendra Rao, preceding paper) were separately treated with alkaline borohydride. The (β-eliminated oligosaccharides were subjected to single and sequential digestion with specific glycosidases and the products analysed by gas liquid chromatography. The studies revealed that carbohydrate moieties were present as mannose, Man-Man-, and trisaccharide structures, namely, (a) GIc-Man-Man-, (b) Gal-Man-Man, (c) Man-Man-Man-, (d) GlcNAc-Man-Man-, and (e) Xyl-Man-Man. None of the glycopeptides contained all the trisaccharide structures (a) to (e). Type 1 glycopeptide contained structures (a), (b) and (c); type 2, (a) and (d) and type 3, (a), (b) and (e). The number of carbohydrate units (mono-, di-and trisaccharides) present in the major glycopeptides was determined and tentative structures for the glycopeptides proposed. Carbohydrate units appeared to occur in clusters of 4 to 7 in each glycopeptide, a structure unique to the carbohydrate moiety in Aspergillus niger glucoamylase. Based on carbohydrate analysis and yields of glycopeptide, the number of units of each type of glycopeptide present in glucoamylase II was tentatively calculated to give two of type Man:Glc:Gal = 12-15:l:l, one of type Man:Glc:GlcN = 10-l1:1:2 and one of type Man :GIc :Gal:Xyl = 4-8:0.1:0.5-0.8:0.3-1 glycopeptides

Comparative studies on glucoamylases from three fungal sources

Five commercial preparations of glucoamylases (three from Aspergillus niger, one each from Aspergillus foetidus and Aspergillus candidus) were purified by ultrafiltration, Sepharose-gel filtration and DEAE-sephadex chromatography. Two forms of the enzyme, namely glucoamylase I and glucoamylase II were obtained from the fungi except from one strain of A. Niger. All the enzymes appeared homogeneous by electrophoresis and ultracentrifugation. The specific activities varied between 85 and 142 units. The pH and temperature optima were between 4 and 5, and 60°C respectively. The molecular weight as determined by the sodium dodecyl sulphate-polyacrylamide gel electrophoresis ranged from 75,000 to 79,000 for glucoamylase I and 60,000 to 72,000 for glucoamylase II. Only A. niger glucoamylases contained phenylalanine at the N-terminal end. The amino acid composition of the enzymes was generally similar. However, A. niger and A. foetidus glucoamylases, in contrast to A. candidus enzymes, contained greater percentage of acidic than of basic amino acids. The enzymes contained 15 to 30% carbohydrate and 49 to 57 residues of monosaccharides per mol. A. niger enzymes contained mannose, glucose, galactose, xylose and glucosamine but the A. candidus enzyme lacked xylose and glucose and only xylose was absent in A, foetidus enzymes. Majority of the carbohydrate moieties were O-glycosidically linked through mannose to the hydroxyl groups of seline and threonine of the polypeptide chain

Studies on carbohydrate moieties of Aspergillus niger glucoamylase. II: Isolation, purification and characterization of glycopeptides

Six glycopeptide fractions namely GP-C1, GP-C2, GP-C3a, GP-C3b, GP-D, and GP-D2 were isolated after exhaustive digestion of glucoamylase II (Glucozyme) from Aspergillus niger with pronase. They were purified using gel-filtration. high-voltage paper electrophoresis and ion-exchange chromatography on Dowex-50 and Dowex-1. They appeared homogeneous on electrophoresis under different conditions of pHs. The molecular weights ranged from 1600 and 4000 for these glycopeptides. Ally of them contained serine at the N-terminal end. Serine and threonine were the major amino acids with glycine, alanine, proline and tryosine present as minor constituents. Carbohydrate analysis revealed the presence of different sugars. Based on this, the glycopeptides were grouped into three types: (1) GP-C1 and GP-C2 containing mannose, glucose and galactose; (2) GP-C3a, and GP-C3b,containing mannose glucose and glucosamine; and (3) GP-D1 and GP-D2, containing mannose. glucose, galactose and xylose. Most sugar constituents in each glycopeptide occured in non-integral ratios implying a microheterogeneity of the carbohydrate moiety in Aspergillus niger glucoamylase II

Bilarge neutrino mixing from supersymmetry with high-scale nonrenormalizable interactions

We suggest a supersymmetric (SUSY) explanation of neutrino masses and mixing, where nonrenormalizable interactions in the hidden sector generate lepton number violating Majorana mass terms for both right-chiral sneutrinos and neutrinos. It is found necessary to start with a superpotential including an array of gauge singlet chiral superfields. This leads to nondiagonal $\Delta L = 2$ mass terms and almost diagonal SUSY breaking $A$-terms. As a result, the observed pattern of bilarge mixing can be naturally explained by the simultaneous existence of the seesaw mechanism and radiatively induced masses. Allowed ranges of parameters in the gauge singlet sector are delineated, corresponding to each of the cases of normal hierarchy, inverted hierarchy and degenerate neutrinos.Comment: 19 pages, 5 figures. Minor modifications are made in the title and the text, some new references are added. To appear in this form in Physical Review

ADVANCED RECEIVER ARCHITECTURES IN RADIOFREQUENCY APPLICATIONS

The general principles of several types of receivers fall under the two main headings of TRF (tuned radio frequency)receivers, where the received signal is processed at the incoming frequency right up to the detector stage, and the superhet(supersonic heterodyne) receiver, where the incoming signal is translated (sometimes after some amplification at theincoming frequency) to an intermediate frequency for further processing. There are however, a number of variants of each ofthese two main types. Regeneration (‘reaction’ or ‘tickling’) may be applied in a TRF receiver, to increase both its sensitivityand selectivity. This may be carried to the stage where the RF amplifier actually oscillates – either continuously, so that thereceiver operates as a synchrodyne or homodyne, or intermittently, so that the receiver operates as a super-regenerativereceiver, both of which have been described previously. The synchrodyne or homodyne may be considered alternatively as asuperhet, where the IF (intermediate frequency) is 0 Hz. In this paper we present the new type of receiver architectureswhich work in radiofrequencies.Keywords: supersonic heterodyne, tuned radio frequency

Adverse drug reactions due to cancer chemotherapy in a tertiary care hospital in south Karnataka: a prospective observational study

Background: Cancer is a multi-cellular disease which can arise from any cell type and organs. Adverse drug reactions (ADR) are undesirable consequence of cancer chemotherapeutic drugs. A great importance has to be given for their assessment, detection, monitoring, reporting and preventing these ADR for the beneficial effects of the patients. So the present study was undertaken for the purpose of detecting and quantifying those adverse reactions which is of some importance in therapeutic setting.Methods: A prospective observational study conducted in chemotherapy ward, male and female patients of any age receiving cancer chemotherapy and presenting with ADR’s in duration of 3 months.Results: 160 patients were observed. Out of 160 patients 123 presented with ADR’s. Most common ADR’s were loss of appetite (67.6), diarrhea (61.8%), vomiting (21.5%), nausea (17.7%), anemia (24.7%). Cisplatin, paclitaxel, oxaliplatin, doxorubicin, gefitinib are common drugs causing ADR’s.Conclusions: Cancer chemotherapeutic drugs are associated with various adverse reactions. This study shows the importance of active monitoring of these reactions and measures to prevent their effects early in the treatment of cancer

ADVANCED RECEIVER ARCHITECTURES IN RADIO-FREQUENCY APPLICATIONS

The general principles of several types of receivers fall under the two main headings of TRF (tuned radiofrequency) receivers, where the received signal is processed at the incoming frequency right up to the detector stage, and thesuperhet (supersonic heterodyne) receiver, where the incoming signal is translated (sometimes after some amplification atthe incoming frequency) to an intermediate frequency for further processing. There are however, a number of variants ofeach of these two main types. Regeneration (‘reaction’ or ‘tickling’) may be applied in a TRF receiver, to increase both itssensitivity and selectivity. This may be carried to the stage where the RF amplifier actually oscillates – either continuously,so that the receiver operates as a synchrodyne or homodyne, or intermittently, so that the receiver operates as a superregenerativereceiver, both of which have been described previously. The synchrodyne or homodyne may be consideredalternatively as a superhet, where the IF (intermediate frequency) is 0 Hz. In this paper we present the new type of receiverarchitectures which work in radiofrequencies.Keywords: Supersonic Heterodyne, Tuned Radio Frequency

Supergravity can reconcile dark matter with lepton number violating neutrino masses

Supersymmetry offers a cold dark matter candidate, provided that lepton number is {\em not violated by an odd number of units}. On the other hand, lepton number violation by even (two) units gives us an attractive mechanism of neutrino mass generation. Here we offer an explanation of this, in a supergravity framework underlying a supersymmetric scenario, the essential feature being particles carrying lepton numbers, which interact only gravitationally with all other known particles. It is shown that one can have the right amount of $\Delta L = 2$ effect giving rise to neutrino masses, whereas the lifetime for $\Delta L = 1$ decays of the lightest supersymmetric particle can be prolonged beyond the present age of the universe.Comment: 8 pages, significant changes in the conceptual ideas and presentation of the paper, minor chages in the title and abstract, added few references. This is to appear in Physical Review

Meningioma - a Cause of Sudden Death

Background: Sudden unexpected death of an apparently healthy individual is an expected event in the life of a forensic expert. Neurological causes account for only 15% of all sudden deaths of which deaths from an undiagnosed primary intracranial neoplasm is exceptionally rare. Meningioma is a common intracranial tumor and it is rarely associated with sudden, unexpected deaths.Case Report: We report one such case of sudden death in a 32-year old male with an olfactory meningioma without any prior history of neurological symptoms raising queries regarding the cause of death.Conclusion: This case illustrates the possibility of meningioma remaining silent till middle age and can present with sudden onset of seizures which may lead to fatality

Kinetics and mechanism of oxidation of erythro-series pentoses and hexoses by N-chloro-p-toluenesulfonamide

The kinetics and mechanism of oxidation of D-glucose, D-mannose, D-fructose, D-arabinose, and D-ribose with chloramine-T in alkaline medium were studied. The rate law, rate = k Chloramine-T] Sugar] HO-](2), was observed. The rate of the reaction was influenced by a change in ionic strength of the medium, and the dielectric effect was found to be negative. The latter enabled the computation of d(AB), the size of the activated complex. The reaction rate was almost doubled in deuterium oxide. Activation energies were calculated from the Arrhenius plots. HPLC and GLC-MS analyses of the products indicated that the sugars were oxidized to a mixture of aldonic acids, consisting of arabinonic, ribonic, erythronic, and glyceric acids. Based on these data, a plausible mechanism involving the aldo-enolic anions of pentoses and keto-enolic anions of hexoses is suggested. (C) 1998 Elsevier Science Ltd. All rights reserved