Development of an operational substrate for ZapA, a metalloprotease secreted by the bacterium Proteus mirabilis

The protease ZapA, secreted by Proteus mirabilis, has been considered to be a virulence factor of this opportunistic bacterium. The control of its expression requires the use of an appropriate methodology, which until now has not been developed. The present study focused on the replacement of azocasein with fluorogenic substrates, and on the definition of enzyme specificity. Eight fluorogenic substrates were tested, and the peptide Abz-Ala-Phe-Arg-Ser-Ala-Ala-Gln-EDDnp was found to be the most convenient for use as an operational substrate for ZapA. A single peptide bond (Arg-Ser) was cleaved with a Km of 4.6 µM, a k cat of 1.73 s-1, and a catalytic efficiency of 376 (mM s)-1. Another good substrate for ZapA was peptide 6 (Abz-Arg-Pro-Pro-Gly-Phe-Ser-Pro-Phe-Arg-Gln-EDDnp) which was cleaved at a single bond (Phe-Ser) with a Km of 13.6 µM, a k cat of 3.96 s-1 and a catalytic efficiency of 291 (mM s)-1. The properties of the amino acids flanking the scissile bonds were also evaluated, and no clear requirement for the amino acid residue at P1 was found, although the enzyme seems to have a preference for a hydrophobic residue at P2.Universidade de São PauloUniversidade Federal de São Paulo (UNIFESP)Universidade Estadual de São PauloInstituto ButantanUNIFESPSciEL

Porto Oscillation Code (POSC)

The Porto Oscillation Code (POSC) has been developed in 1995 and improved over the years, with the main goal of calculating linear adiabatic oscillations for models of solar-type stars. It has also been used to estimate the frequencies and eigenfunctions of stars from the pre-main sequence up to the sub-giant phase, having a mass between 0.8 and 4 solar masses. The code solves the linearised perturbation equations of adiabatic pulsations for an equilibrium model using a second order numerical integration method. The possibility of using Richardson extrapolation is implemented. Several options for the surface boundary condition can be used. In this work we briefly review the key ingredients of the calculations, namely the equations, the numerical scheme and the output.Comment: Accepted for publication in Astrophysics and Space Science

ZapA, a possible virulence factor from Proteus mirabilis exhibits broad protease substrate specificity

The opportunistic bacterium Proteus mirabilis secretes a metalloprotease, ZapA, considered to be one of its virulence factors due to its IgA-degrading activity. However, the substrate specificity of this enzyme has not yet been fully characterized. In the present study we used fluorescent peptides derived from bioactive peptides and the oxidized ß-chain of insulin to determine the enzyme specificity. The bradykinin- and dynorphin-derived peptides were cleaved at the single bonds Phe-Ser and Phe-Leu, with catalytic efficiencies of 291 and 13 mM/s, respectively. Besides confirming already published cleavage sites, a novel cleavage site was determined for the ß-chain of insulin (Val-Asn). Both the natural and the recombinant enzyme displayed the same broad specificity, demonstrated by the presence of hydrophobic, hydrophilic, charged and uncharged amino acid residues at the scissile bonds. Native IgA, however, was resistant to hydrolysis by ZapA.Universidade de São Paulo Instituto de Ciências Biomédicas Departamento de MicrobiologiaInstituto Butantan CEPID-FAPESP Centro de Toxinologia AplicadaUniversidade Federal de São Paulo (UNIFESP) CEPID-FAPESP Centro de Toxinologia AplicadaUniversidade Estadual Paulista CEPID-FAPESP Centro de Toxinologia AplicadaUNIFESP, CEPID-FAPESP Centro de Toxinologia AplicadaSciEL

Photoactivatable prodrugs of butyric acid based on new coumarin fused oxazole heterocycles

New coumarin fused oxazoles were investigated as photosensitive units for carboxylic acid groups using butyric acid as a model compound. 6-Oxo-6H-benzopyrano[6,7-d]oxazol-8-yl)methyl derivatives possessing various (hetero)aromatic substituents at position 2 of the heterocyclic system were used in the synthesis of ester conjugates of butyric acid. Photolysis at selected wavelengths in methanol/HEPES buffer (80:20) solutions, monitored by HPLC/UV and 1H NMR, produced the complete release of butyric acid. The shorter irradiation times for cleavage at longer wavelengths occurred for the conjugate with a 4-oxo-4H-benzopyran-2-yl substituent and thus (6-oxo-2-(4-oxo-4H-benzopyran-2-yl)-6H-benzopyrano[6,7-d]oxazol-8-yl)methyl has potential as a candidate photosensitive moiety for butyric acid prodrugs.Thanks are due to the Fundação para a Ciência e Tecnologia (FCT, Portugal) for financial support to the NMR portuguese network (PTNMR, Bruker Avance III 400-Univ. Minho), FCT and FEDER (European Fund for Regional Development)-COMPETE-QREN-EU for financial support to the research centre CQ/UM [PEst-C/QUI/UI0686/2013 (FCOMP-01-0124-FEDER-022716)] and a PhD grant to A.M.S.S. (SFRH/BD/80813/2011) is also acknowledged

Large atom number dual-species magneto-optical trap for fermionic 6Li and 40K atoms

We present the design, implementation and characterization of a dual-species magneto-optical trap (MOT) for fermionic 6Li and 40K atoms with large atom numbers. The MOT simultaneously contains 5.2x10^9 6Li-atoms and 8.0x10^9 40K-atoms, which are continuously loaded by a Zeeman slower for 6Li and a 2D-MOT for 40K. The atom sources induce capture rates of 1.2x10^9 6Li-atoms/s and 1.4x10^9 40K-atoms/s. Trap losses due to light-induced interspecies collisions of ~65% were observed and could be minimized to ~10% by using low magnetic field gradients and low light powers in the repumping light of both atomic species. The described system represents the starting point for the production of a large-atom number quantum degenerate Fermi-Fermi mixture

Nitrate Reductase And Glutamine Synthetase Activities In S1 Endogamic Families Of The Maize Populations Sol Da Manhã Nf And Catetão

The possibility of improving nitrogen use efficiency in maize was investigated using S1 endogamic families of the populations Sol da Manhã NF and Catetão. A simple 10 × 10 lattice design was adopted and the trials carried out at the experimental field of MITLA AGRÍCOLA LTDA, in Uberlândia, State of Minas Gerais, during the 1994/95 planting season. Based on grain production figures, the three best and three worst performing S1 endogamic families were selected for this study. These were pooled to form four sub-populations denominated NFB, NFR (the best and worst families, respectively, of the Sol da Manhã NF variety), CATB and CATR (the best and worst families, respectively, of the Catetão variety). Each of these sub-populations was evaluated under greenhouse conditions. The experimental design was factorial with treatments arranged in randomized blocks. Sample replicates consisted of pots with four plants. Feeding with modified Hoagland's nutrient solution began on the seventh day after sowing. The study involved four nitrogen regimes, where varying proportions of NO3 - and NH4 + were formulated, such that the nutrient solution contained the following mixtures: 75% NO3 -: 25% NH4 +; 25% NO3 -: 75% NH4 +; 50% NO3 -: 50% NH4 + (all high N mixtures) and 5% NO3 -: 5% NH4 + (low N mixture). Twenty-five days after planting, the activities of the enzymes nitrate reductase and glutamine synthetase (transferase and synthetase assays) were determined for the leaves using the third topmost expanded leaf of the four plants in each pot. The data show that glutamine synthetase (transferase assay) and nitrate reductase activities were efficient in discriminating the S1 endogamic families and could therefore be useful biochemical parameters in breeding programs seeking nitrogen use efficiency.13188102Alfoldi, Z., Pinter, L., Feil, B., Accumulation and partitioning of biomass and soluble carbohydrates in maize seedlings as affected by source of nitrogen, nitrogen concentration and cultivar (1992) Journal of Plant Nutrition, 15, pp. 2567-2583Balko, L.G., Russel, W.A., Effects of rates of nitrogen fertilizer on maize inbred lines and hybrid progeny-I. Prediction of yield response (1980) Maydica, 25, pp. 65-79Balko, L.G., Russel, W.A., Effects of rates of nitrogen fertilizer on maize inbred lines and hybrid progeny. II. Correlations among agronomic traits (1980) Maydica, 25, pp. 81-94Bänziger, M., Lafitte, H.R., Edmeades, G.O., Intergenotypic competition during evaluation of maize progenies under limited and adequate N supply (1995) Field Crops Research, 44, pp. 25-31Below, F.E., Gentry, L.E., Maize productivity as influenced by mixed nitrogen supplied before or after anthesis (1992) Crop Science, 32, pp. 163-168Beuchamp, E.G., Kannenberg, L.W., Hunter, R.B., Nitrogen accumulation and translocation in crop genotypes following silking (1976) Agronomy Journal, 68, pp. 418-422Cacco, G., Ferrari, G., Saccomani, M., Genetic variability of the efficiency of nutrient utilization by maize (Zea mays L.) (1983) Genetic aspects of plant nutrition, pp. 435-439. , SARIC, M.R. & LAUGHMAN, B.C. (Eds.) Martinus Nijhoff Publishers, The HagueChevalier, P., Schrader, L.E., Genotypic differences in nitrate absorption and partitioning of N among plant parts in maize (1977) Crop Science, 17, pp. 897-901Cregan, P.B., Van Berkum, P., Genetics of nitrogen metabolism and physiological/biochemical selection for increased grain crop productivity (1984) Theoretical and Applied Genetics, 67, pp. 97-111Eghball, B., Maranville, J.W., Root development and nitrogen influx of corn genotypes grown under combined water and nitrogen stress (1993) Agronomy Journal, 85, pp. 147-152Eichelberger, K.D., Lambert, R.J., Below, F.E., Hageman, R.H., Divergent phenotypic recurrent selection for nitrate reductase activity in maize. I. Selection and correlated responses (1989) Crop Science, 29, pp. 1393-1397Eichelberger, K.D., Lambert, R.J., Below, F.E., Hageman, R.H., Divergent phenotypic recurrent selection for nitrate reductase activity in maize. II. Efficient use of fertilizer nitrogen (1989) Crop Science, 29, pp. 1398-1402Feil, B., Thiraporn, R., Stamp, P., In vitro nitrate reductase activity of laboratory-grown seedlings as an indirect selection criterion for maize (1993) Crop Science, 33, pp. 1280-1286Ferguson, A.R., Sims, A.P.A., Inactivation in vivo of glutamine synthetase and NAD-specific glutamate dehydrogenase, its role in the regulation of glutamine synthesis in yeasts (1971) Journal of General Microbiology, 69, pp. 423-427Fernandes, M.S., Rossielo, O.P., Nitrogen mineral in plant physiology and plant nutrition (1995) Critical Reviews in Plant Sciences, 14, pp. 111-148Gentry, L.E., Below, F.E., Maize productivity as influenced by form and availability of nitrogen (1993) Crop Science, 33, pp. 491-497Hageman, R.H., Lambert, R.J., The use of physiological traits for corn improvement (1998) Corn and Corn Improvement. 3 ed., pp. 431-461. , SPRAGUE, G.F. (Ed.) American Society of Agronomy, MadisonJackson, W.A., Volk, R.J., Morgan, M.A., Pan, W.L., Teyker, R.H., Nitrogen uptake and partitioning by roots (1986) Proceeding of the First Annual Penn State Symposium in Plant Physiology, pp. 83-104. , SHANNON, J.C.KNIEVEL, D.P. & BOYER, C.D. (Eds.) American Society of Plant Physiology, BaltimoreJelenic, D., Sukalovic, H.T., The effect of nitrogen on the activity of some enzymes of nitrogen metabolism during ontogenesis of maize kernel hybrids (1983) Genetic aspects of plant nutrition, pp. 237-242. , SARIC, M.R. & LAUGHMAN, B.C. (Eds.) Martinus Nijhoff Publishers, The HagueKamprath, E.J., Moll, R.H., Rodrigues, N., Effects of nitrogen fertilization and recurrent selection on performance of hybrid population of corn (1982) Agronomy Journal, 74, pp. 955-958Lafitte, H.R., Edmeades, G.O., Improvement for tolerance to low soil nitrogen in tropical maize. I. Selection criteria (1994) Field Crops Research, 39, pp. 1-14Lafitte, H.R., Edmeades, G.O., Association between traits in tropical maize inbred lines and their hybrids under high and low soil nitrogen (1995) Maydica, 40, pp. 259-267Li, X.Z., Dawn, L.E., Clibertic, M., Oaks, A., Effect of glutamine on the induction of nitrate reductase (1995) Physiologia Plantarum, 93, pp. 740-744Machado, A.T., (1997) Perspectiva do melhoramento genético em milho (Zea mays L.) visando eficiência na utilização do nitrogênio, , Rio de Janeiro, Universidade Federal do Rio de Janeiro. 219p. Tese de DoutoradoMachado, A.T., Magalhães, J.R., Magnavaca, R., Silva, M.R., Determinação da atividade de enzimas envolvidas no metabolismo do nitrogênio em diferentes genótipos de milho (1992) Revista Brasileira de Fisiologia Vegetal, 4, pp. 45-47Machado, A.T., Magalhães, J.R., Melhoramento de milho para uso eficiente de nitrogênio sob condições de estresse (1995) Anais..., pp. 321-342. , SIMPÓSIO INTERNACIONAL SOBRE ESTRESSE AMBIENTAL: O MILHO EM PERSPECTIVA, 1992. Belo Horizonte. Sete Lagoas: EMBRAPA/CNPMSMagalhães, J.R., Huber, D.M., Growth and ammonium assimilation enzyme activity in response to nitrogen forms and pH control (1989) Journal of Plant Nutrition, 12, pp. 985-996Magalhães, J.R., Huber, D.M., Ammonium assimilation in different plant species as affected by nitrogen form and pH control in solution culture (1989) Fertilizer Research, 21, pp. 1-6Magalhães, J.R., Huber, D.M., Responses of ammonium assimilation enzymes to nitrogen treatments in different plant species (1991) Journal of Plant Nutrition, 14, pp. 175-185Magalhães, J.R., Fernandes, M.S., Absorção e metabolismo do nitrogênio sob condições de stress (1993) Anais..., pp. 249-266. , SIMPÓSIO BRASILEIRO DE NITROGÊNIO EM PLANTAS, 1., Rio de Janeiro, 1990. Rio de Janeiro: UFRRJMagalhães, J.R., Machado, A.T., Fernandes, M.S., Silveira, J.A.G., Nitrogen assimilation efficiency in maize genotypes under ammonia stress (1993) Revista Brasileira Fisiologia Vegetal, 5, pp. 163-166Magalhães, J.R., Machado, A.T., Biochemical parameters selecting maize for nitrogen assimilation efficiency under stress conditions (1995) Anais..., pp. 345-367. , SIMPÓSIO INTERNACIONAL SOBRE ESTRESSE AMBIENTAL: O MILHO EM PERSPECTIVA, 1992. Belo Horizonte. Sere Lagoas: EMBRAPA/CNPMSMolaretti, G., Bosio, M., Gentinetta, E., Motto, M., Genotypic variability for N-related traits in maize. Identification of inbred lines with high or low levels of NO3-N in the stalks (1987) Maydica, 32, pp. 309-323Moll, R.H., Kamprath, E.J., Effects of population density upon agrononic traits associated with genetic increases in yield of Zea mays L. (1977) Agronomy Journal, 69, pp. 81-85Moll, R.H., Jackson, A., Mikkelsen, A., Recurrent selection for maize grain yield: Dry matter and nitrogen accumulation and partitioning changes (1994) Crop Science, 34, pp. 874-881Mori, T.E.S., (1981) Metabolismo do nitrogênio durante a fase do desenvolvimento reprodutivo da soja, , Campinas: UNICAMP/Biologia Vegetal. 94p. Tese de MestradoMurulli, B.I., Paulsen, G.M., Improvement of nitrogen use efficiency and its relationship to other traits in maize (1981) Maydica, 26, pp. 63-73Pan, W.L., Kamprath, E.J., Moll, R.H., Jackson, W.A., Prolificacy in corn: Its effects on nitrate and ammonium uptake and utilization (1984) Soil Science Society of America Journal, 48, pp. 1101-1106Paterniani, E., Maize breeding in the tropics (1990) Critical Reviews in Plant Sciences, 9, pp. 125-154Pollmer, W.G., Eberhard, D., Klein, D., Dhillon, B.S., Genetic control of nitrogen uptake and translocation in maize (1979) Crop Science, 19, pp. 82-86Reed, A.J., Below, F.E., Hageman, R.H., Grain protein accumulation and the relationship between leaf nitrate reductase and protease activities during grain development in maize (Zea mays L.) (1980) Plant Physiology, 66, pp. 1179-1183Rhodes, D., Rendon, G.A., Stewart, G.R., The control of glutamine synthetase level in Lemna minor L. (1975) Planta, 125, pp. 201-211Rizzi, E., Balconi, C., Morselli, A., Motto, M., Genotypic variation and relationships among N-related traits in maize hybrid progenies (1995) Maydica, 40, pp. 253-258Salsac, L., Chaillou, S., Morot-Gaudry, J.F., Leisant, C., Jolivet, E., Nitrate and ammonium nutrition in plants (1987) Plant Physiology and Biochemistry, 25, pp. 805-812Sherrard, J.H., Lambert, R.J., Messmer, N.J., Bellow, F.E., Hageman, H., Plant breeding for efficient plant use of nitrogen (1984) Nitrogen in Crop Production, pp. 363-378. , HAUCK, R.D. (Ed.) ASA/CSSA/SSSA, MadisonSherrard, J.H., Lambert, R.J., Below, F.E., Dunand, R.T., Messmer, M.J., Willman, M.R., Winklels, C.S., Hageman, R.H., Use of physiological traits, especially those nitrogen metabolism, for selection in maize (1986) Biochemical Basis of Plant Breeding, pp. 109-130. , NEYRA, C.D. (Ed.) Boca Raton: CRCSmiciklas, K.D., Below, F.E., Role of nitrogen form in determining yield of field-grown maize (1992) Crop Science, 32, pp. 1220-1225Sodek, L., Mecanismos bioquímicos de enchimento de grãos em leguminosas (1989) Anais..., 1989, pp. 115-121. , REUNIÃO BRASILEIRA DE FISIOLOGIA VEGETAL, 2., Piracicaba. Piracicaba: SBFV/ESALQTsai, C.Y., Huber, D.M., Glover, D.V., Warren, W.L., Relationship of N deposition to grain yield and N response of three maize hybrids (1984) Crop Science, 24, pp. 277-28

The Fueling and Evolution of AGN: Internal and External Triggers

In this chapter, I review the fueling and evolution of active galactic nuclei (AGN) under the influence of internal and external triggers, namely intrinsic properties of host galaxies (morphological or Hubble type, color, presence of bars and other non-axisymmetric features, etc) and external factors such as environment and interactions. The most daunting challenge in fueling AGN is arguably the angular momentum problem as even matter located at a radius of a few hundred pc must lose more than 99.99 % of its specific angular momentum before it is fit for consumption by a BH. I review mass accretion rates, angular momentum requirements, the effectiveness of different fueling mechanisms, and the growth and mass density of black BHs at different epochs. I discuss connections between the nuclear and larger-scale properties of AGN, both locally and at intermediate redshifts, outlining some recent results from the GEMS and GOODS HST surveys.Comment: Invited Review Chapter to appear in LNP Volume on "AGN Physics on All Scales", Chapter 6, in press. 40 pages, 12 figures. Typo in Eq 5 correcte

Measurement of D*+/- meson production in jets from pp collisions at sqrt(s) = 7 TeV with the ATLAS detector

This paper reports a measurement of D*+/- meson production in jets from proton-proton collisions at a center-of-mass energy of sqrt(s) = 7 TeV at the CERN Large Hadron Collider. The measurement is based on a data sample recorded with the ATLAS detector with an integrated luminosity of 0.30 pb^-1 for jets with transverse momentum between 25 and 70 GeV in the pseudorapidity range |eta| < 2.5. D*+/- mesons found in jets are fully reconstructed in the decay chain: D*+ -> D0pi+, D0 -> K-pi+, and its charge conjugate. The production rate is found to be N(D*+/-)/N(jet) = 0.025 +/- 0.001(stat.) +/- 0.004(syst.) for D*+/- mesons that carry a fraction z of the jet momentum in the range 0.3 < z < 1. Monte Carlo predictions fail to describe the data at small values of z, and this is most marked at low jet transverse momentum.Comment: 10 pages plus author list (22 pages total), 5 figures, 1 table, matches published version in Physical Review