265 research outputs found

    A Note On Jump Symmetric n-Sigraph

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    For standard terminology and notion in graph theory we refer the reader to West; the nonstandard will be given in this paper as and when required. We treat only finite simple graphs without self loops and isolates

    Interactions of 3' terminal and 5' terminal regions of physalis mottle virus genomic RNA with its replication complex

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    Physalis mottle virus (PhMV) belongs to the tymogroup of positive-strand RNA viruses with a genome size of 6 kb. Crude membrane preparations from PhMV-infectedNicotiana glutinosa plants catalyzed the synthesis of PhMV genomic RNA from endogenously bound template. Addition of exogenous gnomic RNA enhanced the synthesis which was specifically inhibited by the addition of sense and antisense transcripts corresponding to 3' terminal 242 nucleotides as well as the 5' terminal 458 nucleotides of PhMV genomic RNA while yeast tRNA or ribosomal RNA failed to inhibit the synthesis. This specific inhibition suggested that the 5' and 3' non-coding regions of PhMV RNA might play an important role in viral replication

    Similarities in the genomic sequence and coat protein structure of plant virsuses

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    The genomic sequences of several RNA plant viruses including cucumber mosaic virus, brome mosaic virus, alfalfa mosaic virus and tobacco mosaic virus have become available recently. The former two viruses are icosahedral while the latter two are bullet and rod shaped, respectively in particle morphology. The non-structural 3a proteins of cucumber mosaic virus and brome mosaic virus have an amino acid sequence homology of 35% and hence are evolutionarily related. In contrast, the coat proteins exhibit little homology, although the circular dichroism spectrum of these viruses are similar. The non-coding regions of the genome also exhibit variable but extensive homology. Comparison of the brome mosaic virus and alfalfa mosaic virus sequences reveals that they are probably related although with a much larger evolutionary distance. The polypeptide folds of the coat protein of three biologically distinct isometric plant viruses, tomato Bushy stunt virus, southern bean mosaic virus and satellite tobacco necrosis virus have been shown to display a striking resemblance. All of them consist of a topologically similar 8-standard β-Barrel. The implications of these studies to the understanding of the evolution of plant viruses will be discussed

    Structure and assembly of Sesbania mosaic virus

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    Sesbania mosaic virus (SeMV) is a ss-RNA (4149 nt) plant sobemovirus isolated from farmer’s field around Tirupathi, Andhra Pradesh. The viral capsid (30 nm diameter) consists of 180 copies of protein subunits (MW 29 kDa) organized with icosahedral symmetry. In order to understand the mechanism of assembly of SeMV, a large number of deletion and substitution mutants of the coat protein (CP) were constructed. Recombinant SeMV CP (rCP) as well as the N-terminal rCP deletion mutant ΔN22 were found to assemble in E. coli into virus-like particles (VLPs). ΔN36 and ΔN65 mostly formed smaller particles consisting of 60 protein subunits. Although particle assembly was not affected due to the substitution of aspartates (D146 and D149) that coordinate calcium ions by asparagines, the stability of the resulting capsids was drastically reduced. Deletion of residues forming a characteristic β-annulus at the icosahedral 3-folds did not affect the assembly of VLPs. Mutation of a single tryptophan, which occurs near the icosahedral fivefold axis to glutamate or lysine, resulted in the disruption of the capsid leading to soluble dimers that resembled the quasi-dimer structure of the native virus. Replacement of positively charged residues in the amino terminal segment of CP resulted in the formation of empty shells. Based on these observations, a plausible mechanism of assembly is proposed

    Evolutionary relationship of alfalfa mosaic virus with cucumber mosaic virus and brome mosaic virus

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    The amino acid sequences of the non-structural protein (molecular weight 35,000; 3a protein) from three plant viruses-cucumber mosaic, brome mosaic and alfalfa mosaic have been systematically compared using the partial genomic sequences for these three viruses already available. The 3a protein of cucumber mosaic virus has an amino acid sequence homology of 33.7% with the corresponding protein of brome mosaic virus. A similar protein from alfalfa mosaic virus has a homology of 18.2% and 14.2% with the protein from brome mosaic virus and cucumber mosaic virus, respectively. These results suggest that the three plant viruses are evolutionarily related, although, the evolutionary distance between alfalfa mosaic virus and cucumber mosaic virus or brome mosaic virus is much larger than the corresponding distance between the latter two viruses

    Purification and kinetic mechanism of 5,10-metliyienetetrahydrofolate reductase from sheep liver

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    5,10-Methylenetetrahydrofolate reductase (EC 1.1.1.68) was purified from the cytosolic fraction of sheep liver by (NH4)2 SO4 fractionation, acid precipitation, DEAE-Sephacel chromatography and Blue Sepharose affinity chromatography. The homogeneity of the enzyme was established by sodium dodecyl sulphate-polyacrylamide gel electrophoresis, ultracentrifugation and Ouchterlony immunodiffusion test. The enzyme was a dimer of molecular weight 1,66,000 ± 5,000 with a subunit molecular weight of 87,000 ±5,000. The enzyme showed hyperbolic saturation pattern with 5-methyltetrahydrofolate. K 0.5 values for 5-methyltetrahydrofolate menadione and NADPH were determined to be 132 MM, 2.45 MM and 16 MM. The parallel set of lines in the Lineweaver-Burk plot, when either NADPH or menadione was varied at different fixed concentrations of the other substrate; non-competitive inhibition, when NADPH was varied at different fixed concentrations of NADP; competitive inhibition, when menadione was varied at different fixed concentrations of NADP and the absence of inhibition by NADP at saturating concentration of menadione, clearly established that the kinetic mechanism of the reaction catalyzed by this enzyme was ping-pong

    Arginine residues involved in binding of tetrahydrofolate to sheep liver serine hydroxymethyltransferase

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    The arginine residue(s) necessary for tetrahydrofolate binding to sheep liver serineh ydroxymethyltransferase were located by phenylglyoxal modification. The incorporation of [7-14C]phenylglyoxal indicated that 2 arginine residues were modified per subunit of the enzyme and the modification of these residues was prevented by tetrahydrofolate. In order to locate the sites of phenylglyoxal modification, the enzyme was reacted in the presence and absence of tetrahydrofolate using unlabeled and radioactive phenylglyoxal, respectively. The labeled phenylglyoxal-treated enzyme was digested with trypsin, and the radiolabeled peptides were purified by high-performance liquid chromatography on reversed-phase columns. Sequencing the tryptic peptides indicated that Arg-269 and Arg-462 were the sites of phenylglyoxal modification. Neither a spectrally discernible 495-nm intermediate (characteristic of the native enzyme when substrates are added) nor its enhancement by the addition of tetrahydrofolate, was observed with the phenylglyoxalmodified enzyme. There was no enhancement of the rate of the exchange of the α-proton of glycine upon addition of tetrahydrofolate to the modified enzyme as was observed with the native enzyme. These results demonstrate the requirement of specific arginine residues for the interaction of tetrahydrofolate with sheep liver serine hydroxymethyltransferase

    Interaction of cibacron blue F3G-A and procion red HE-3B with sheep liver 5,10-methylenetetrahydrofolate reductase

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    Cibacron Blue F3G-A, a probe used to monitor nucleotide binding domains in enzymes, inhibited sheep liver 5,10-methylenetetrahydrofolate reductase competitively with respect to 5-methyltetrahydrofolate and NADPH. The Ki values obtained by kinetic methods and the Kd value for the binding of the dye to the enzyme estimated by protein fluorescence quenching were in the range 0.9-1.2 μM. Another triazine dye, Procion Red HE-3B interacted with the enzyme in an essentially similar manner to that observed with Cibacron Blue F3G-A. These results as well as the interaction of the dye with the enzyme monitored by difference spectroscopy and intrinsic protein fluorescence quenching methods indicated that the dye was probably interacting at the active site of the enzyme by binding at a hydrophobic region

    Analisa Kesiapan Integrasi Jaminan Kesehatan Daerah (Jamkesda)

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    The implementation Of National Social Health Insurance by BPJS-Health that has been started on January,I, 2014 gives an impact to integrating local health insurance into national scheme.This study aims to describe implementation of local social health insurance as a basic in formulating policy model whichallows integration of local health insurance, particularly in the area of management, benefit packages, and government payed member in the frame of health decentralization policy. Study design is embeddedmulticases, using case study interpretatif method. Primary and secondary data were collected by explorativeapproach. Study area includes implementation of social local health insurance at 33 provinces, conducted in2013-2014. Results of this study show a gap in understanding and capacity of local authorities in managinglocal health insurance; various characteristics of local social health insurance in term of local monetarycapacity, benefit packages, management, and government payed member. This study recommends toaccomodate public health effort financing into benefit packages scheme, perception equalizing betweennational and local policy maker in understanding policy steps, and giving more flexibility forprovince/district/municipal in local social health insurance integration policy
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