662 research outputs found

    Spectrum Orbit Utilization Program Documentation: SOUP5 Version 3.8 User's Manual, Volume 2, Appendices a Through G

    Get PDF
    The appendixes of the user manual are presented. Input forms which may be used to prepare data for the SOUP5V3.4 of the R2BCSAT-83 data base are given. The IBM job control language which can be used to run the SOUP5 system from a magnetic tape is described. Copies of a run using the delivered tape and IBM OS/MVS Job Control Language card deck are illustrated. Numerical limits on scenario data requests are listed. Error handling, error messages and editing procedures are also listed. Instructions as to how to enter a protection ratio template are given. And relation between PARC prameter, channelization, channel families, and interference categories are also listed

    Type IV pilus of Myxococcus xanthus is a motility apparatus controlled by the frz chemosensory system

    Get PDF
    AbstractAlthough flagella are the best-understood means of locomotion in bacteria [1], other bacterial motility mechanisms must exist as many diverse groups of bacteria move without the aid of flagella [2–4]. One unusual structure that may contribute to motility is the type IV pilus [5,6]. Genetic evidence indicates that type IV pili are required for social gliding motility (S-motility) in Myxococcus, and twitching motility in Pseudomonas and Neisseria[6,7]. It is thought that type IV pili may retract or rotate to bring about cellular motility [6,8], but there is no direct evidence for the role of pili in cell movements. Here, using a tethering assay, we obtained evidence that the type IV pilus of Myxococcus xanthus functions as a motility apparatus. Pili were required for M. xanthus cells to adhere to solid surfaces and to generate cellular movement using S-motility. Tethered cells were released from the surface at intervals corresponding to the reversal frequency of wild-type cells when gliding on a solid surface. Mutants defective in the control of directional movements and cellular reversals (frz mutants) showed altered patterns of adherence that correlate reversal frequencies with tethering. The behavior of the tethered cells was consistent with a model in which the pili are extruded from one cell pole, adhere to a surface, and then retract, pulling the cell in the direction of the adhering pili. Cellular reversals would result from the sites of pili extrusion switching from one cell pole to another and are controlled by the frz chemosensory system

    The ‘CheA’ and ‘CheY’ domains of Myxococcus xanthus FrzE function independently in vitro as an autokinase and a phosphate acceptor, respectively

    Get PDF
    AbstractFrzE is a chemotaxis protein in Myxococcus xanthus which has sequence homology to two different chemotaxis proteins of enteric bacteria, CheA (autokinase) and CheY (phosphate acceptor) [Proc. Natl. Acad. Sci. USA 87 (1990) 5898–5902]. It was also shown that a recombinant FrzE protein was autophosphorylated when incubated in the presence of ATP and Mn2+ [J. Bacteriol. 172 (1990) 6661–6668]. In this study, we further investigated the biochemical properties of FrzE. Two recombinant proteins were produced: one containing only the ‘CheA’ domain of FrzE and the second only the ‘CheY’ domain. The CheA domain polypeptide contained the autokinase activity which was absent from the CheY domain polypeptide. The phosphorylated CheA domain polypeptide as well as the intact FrzE protein were able to transfer phosphate groups to the CheY domain peptide. These results indicate that FrzE has structural as well as functional homologies to CheA and CheY in a single polypeptide

    Nucleotide sequence of the myxobacterial hemagglutinin gene contains four homologous domains.

    Full text link

    Effect of indomethacin and adrenocorticotrophic hormone on renal function in man: An experimental model of inappropriate antidiuresis

    Get PDF
    Effect of indomethacin and adrenocorticotrophic hormone on renal function in man: An experimental model of inappropriate antidiuresis. The effect of prostaglandin synthesis inhibition on basal and ACTH-stimulated adrenal and renal function was investigated in normai volunteers. Data were collected during control and experimental study periods (13 days each). Adrenocorticotrophic hormone (Cosyntropin, 80 U/day) was administered i.v. on days 8 and 9 of each period. Indomethacin (150 mg/day) was given on days 5 through 13 of the experimental period. The subjects ate a constant diet containing 9 mEq of sodium, 100 mEq of potassium, and 2,500 ml of fluid daily. Indomethacin markedly inhibited urinary PGE excretion and plasma PGE concentration. The effect of ACTH alone as compared to the effect of ACTH and indomethacin showed: plasma sodium concentration, 139 ± 1 vs. 131 ± 3 mEg/liter (P < 0.01, mean ± SEM); plasma osmolality, 287 ± 3 vs. 270 ± 3 mOsm/liter (P < 0.01); free water clearance, 97 ± 66 vs. -1100 ± 380 ml/24hr (P < 0.01); urine volume, 2,000 ± 60 vs. 950 ± 200 ml/day (P < 0.01); and urine osmolality 282 ± 12 vs. 720 ± 144 mOsm/liter (P < 0.01). We conclude that the effects of ACTH and prostaglandin synthesis inhibition interact to result in inappropriate antidiuresis.Effet de l'indométhacine et de l'hormone adrénocorticotrope sur la fonction rénale chez l'homme: Un modèle expérimental d'antidiurèse inappropriée. L'effet de l'inhibition de la synthèse de prostaglandine sur la fonction surrénalienne basale et stimulée par l'ACTH et sur la fonction rénale a été étudié chez des sujets normaux volontaires. Les résultats ont été obtenus au cours de périodes contrôles et expérimentales de 13 jours chacune. De l'hormone adrénocorticotrope (Cosyntropin) a été administrée par voie i.v. les 8ème et 9ème jours de chaque période à raison de 80 U par jour. L'indométhacine, 150 mg/jour, a été donnée du 8ème au 13ème jour de la période expérimentale. Les sujets ont été soumis à un régime constant contenant 9 mEq de sodium, 100 mEq de potassium, et 2,500 ml de liquide par jour. L'indométhacine a fortement inhibé l'excrétion urinaire de PGE et abaissé la concentration plasmatique de PGE. L'effet de l'ACTH seul comparé à l'effet de l'ACTH associé à l'indométhacine a montré: une concentration plasmatique de sodium de 139 ± 1 vs. 131 ± 3 mEq/litre (P < 0,01) moyenne et SEM); une osmolalité plasmatique de 287 ± 3 vs. 270 ± 3 mOsm/litre (P < 0,01); une clearance de l'eau libre de 97 ± 66 vs. - 1100 ± 380 ml/24 hr (P < 0,01); un débit urinaire de 2,000 ± 60 vs. 950 ± 200 ml/jour (P < 0,01); et une osmolalité urinaire de 282 ± 12 vs. 720 ± 144 mOsm/litre (P < 0,01). Nous considérons que les effets de l'ACTH et de l'inhibition de la synthèse de prostaglandine se combinent pour déterminer une antidiurése inappropriée

    Investigation of continuous-time quantum walk by using Krylov subspace-Lanczos algorithm

    Get PDF
    In papers\cite{js,jsa}, the amplitudes of continuous-time quantum walk on graphs possessing quantum decomposition (QD graphs) have been calculated by a new method based on spectral distribution associated to their adjacency matrix. Here in this paper, it is shown that the continuous-time quantum walk on any arbitrary graph can be investigated by spectral distribution method, simply by using Krylov subspace-Lanczos algorithm to generate orthonormal bases of Hilbert space of quantum walk isomorphic to orthogonal polynomials. Also new type of graphs possessing generalized quantum decomposition have been introduced, where this is achieved simply by relaxing some of the constrains imposed on QD graphs and it is shown that both in QD and GQD graphs, the unit vectors of strata are identical with the orthonormal basis produced by Lanczos algorithm. Moreover, it is shown that probability amplitude of observing walk at a given vertex is proportional to its coefficient in the corresponding unit vector of its stratum, and it can be written in terms of the amplitude of its stratum. Finally the capability of Lanczos-based algorithm for evaluation of walk on arbitrary graphs (GQD or non-QD types), has been tested by calculating the probability amplitudes of quantum walk on some interesting finite (infinite) graph of GQD type and finite (infinite) path graph of non-GQD type, where the asymptotic behavior of the probability amplitudes at infinite limit of number of vertices, are in agreement with those of central limit theorem of Ref.\cite{nko}.Comment: 29 pages, 4 figure

    An atypical receiver domain controls the dynamic polar localization of the Myxococcus xanthus social motility protein FrzS

    Get PDF
    The Myxococcus xanthus FrzS protein transits from pole-to-pole within the cell, accumulating at the pole that defines the direction of movement in social (S) motility. Here we show using atomic-resolution crystallography and NMR that the FrzS receiver domain (RD) displays the conserved switch Tyr102 in an unusual conformation, lacks the conserved Asp phosphorylation site, and fails to bind Mg2+ or the phosphoryl analogue, Mg2+·BeF3. Mutation of Asp55, closest to the canonical site of RD phosphorylation, showed no motility phenotype in vivo, demonstrating that phosphorylation at this site is not necessary for domain function. In contrast, the Tyr102Ala and His92Phe substitutions on the canonical output face of the FrzS RD abolished S-motility in vivo. Single-cell fluorescence microscopy measurements revealed a striking mislocalization of these mutant FrzS proteins to the trailing cell pole in vivo. The crystal structures of the mutants suggested that the observed conformation of Tyr102 in the wild-type FrzS RD is not sufficient for function. These results support the model that FrzS contains a novel ‘pseudo-receiver domain’ whose function requires recognition of the RD output face but not Asp phosphorylation
    • …
    corecore