2,917 research outputs found

    Characterisation of serine proteinase inhibitors in dry seeds of cultivated pasture grass species : a thesis presented in partial fulfilment of the requirements for the degree of Master of Philosophy in Plant Biology and Biotechnology at Massey University, Palmerston North, New Zealand

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    Content removed due to copyright restriction: Tasneem, M., Cornford, C. A., & McManus, M. T. (1994). Characterization of serine proteinase inhibitors in dry seeds of cultivated pasture grass species. Seed Science Research, 4(3), 335-345. Tasneem, M., Cornford, C.A., McManus, M.T., White, D.W.R. (1993). "Purification and characterisation of a proteinase inhibitor from lolium perenne L." Proceedings of the XVII International Grassland Congress : 8-21 February 1993, Palmerston North, New Zealand, Hamilton, New Zealand, Lincoln, New Zealand, Rockhampton, Australia. (1993). Palmerston North, N.Z. : The Association, c1993.A chymotrypsin inhibitor has been partially purified from Lolium perenne cv. Grasslands Ruanui that is stable at pH 3 and after heating at 80°C for 10 minutes (acid/heat stable). The inhibitor had a native molecular weight of ca. 20-22 kDa determined using a 2.5 cm x 100 cm Sephadex G-75 column and gel electrophoresis indicated that it may be comprised of two subunits that had molecular weights of ca. 11 kDa and 12 kDa. To determine the occurrence of such inhibitors in other grass species, a survey of seeds from several cultivars of pasture grass species was conducted. Seeds of two cultivars of Festuca arundinaceae, cv. Grasslands Garland and cv. Grasslands Roa have been found to contain the most potent chymotrypsin inhibitory activity of the species surveyed. Seeds of two cultivars of an economically-important genus, Lolium, L. perenne cv Grasslands Ruanui and L. x boucheanum cv Grasslands Greenstone also exhibited significant chymotrypsin inhibitory activity, and so these four species were studied further. Using a 2.5 cm x 100 cm gel filtration column, chymotrypsin inhibitory activity eluted as two peaks in all four cultivars examined which had native molecular weights of ca. 20-22 kDa for peak I and ca. 10-12 kDa for peak II. A ca. 12 kDa chymotrypsin inhibitor was observed in peak 1 of F. arundinaceae cv. Grasslands Garland during gel electrophoresis, and was further purified by ion exchange chromatography. Twelve amino acid residues were sequenced from the N-terminal and the protein was found to be homologous with members of the cereal α-amylase inhibitor family. To purify this activity further, a 10 cm x 100 cm gel filtration column was used. This time trypsin inhibitory activity was also assayed and for all four cultivars, both chymotrypsin and trypsin inhibitory activities co-eluted within two peaks, both with similar molecular weights (peak I, 20-22 kDa and peak II, 10-12 kDa) to that observed previously using the smaller gel filtration column. Gel electrophoresis of peak I from all the four cultivars revealed at least six comparatively lower molecular weight chymotrypsin inhibitors ranging from ca. 12 kDa to 3 kDa for the Festuca cultivars, and at least two ranging from ca. 8 kDa and 12 kDa for the Lolium cultivars. However, higher molecular weight trypsin inhibitors were present in Peak I with 5 inhibitors ranging from ca. 12-18 kDa for Festuca, and three ranging from ca. 12-16 kDa for Lolium. Peak II from all the four cultivars contained only one 12 kDa inhibitor band. The 12 kDa inhibitor is active against both trypsin and chymotrypsin. The 12 kDa inhibitor from peak II of F. arundinaceae cv. Grasslands Garland was purified further using an anhydro-trypsin affinity chromatography and then to homogeneity by reverse-phase HPLC. Two inhibitory peaks were separated that had dual trypsin/chymotrypsin inhibitory activity and had an identical 20 amino acid residues at the N-terminal. The two inhibitor polypeptides were found to be homologous to members of the barley trypsin inhibitor family, but did not share homology with the ca. 12 kDa inhibitor protein purified by ion exchange from gel filtration peak I

    G2G_2 holonomy metrics and wrapped D6-branes

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    We determine torsion class constraints for the supergravity background produced by D6-branes wrapping special Lagrangian cycles in a Calabi-Yau 3-fold. We employ a recently introduced method which involves probing the putative background by all possible supersymmetric brane configurations. We then lift this background to 11-dimensions to a product of 4-d Minkowski space and a 7-fold of G2-holonomy. The latter is a particular U(1) bundle over an almost complex manifold of SU(3) structure with specific torsion class constraints. We construct the closed 3- and 4-forms which calibrate the 3- and 4-cycles in the G2-holonomy manifold.Comment: 21 pages, references adde

    The monetary transmission mechanism in Pakistan: a sectoral analysis

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    The present paper takes a first step in investigating the monetary transmission mechanism in Pakistan at a sectoral level. Using quarterly data spanning from 1973:1 to 2003:4, we examine whether monetary policy shocks have different sectoral effects. Taking note of structural transformation of the economy and the monetary and financial reforms during 1990s, we also assess whether the reform process has notable impact on the monetary transmission mechanism. We find evidence supporting sector-specific variation in the real effects of monetary policy. Our results also suggest significant changes in the transmission of monetary shock to real sector of the economy during post-reform period.Monetary transmission mechanism; VAR; Pakistan; Sectoral analysis

    Calibrations, Torsion Classes and Wrapped M-Branes

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    The present work has two goals. The first is to complete the classification of geometries in terms of torsion classes of M-branes wrapping cycles of a Calabi-Yau. The second goal is to give insight into the physical meaning of the torsion class constraints. We accomplish both tasks by defining new energy minimizing calibrations in M-brane backgrounds. When fluxes are turned on, it is these calibrations that are relevant, rather than those which had previously been defined in the context of purely geometric backgrounds

    The Geometry of M-Branes Wrapping Special Lagrangian Cycles

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    We characterize the geometry produced by M5-branes wrapping a Special Lagrangian 3-cycle in a Calabi-Yau 3-fold. The presence of the brane replaces the the Calabi-Yau by a real manifold with an almost complex structure. We show that, in this classification, a distinguished (1,1) form as well as a globally defined (3,0) form play an important role. The requirements of supersymmetry preservation impose constraints on these structures which can be used to classify the background.Comment: 17 pages, correct versio

    Evaluating Real World Income Distributions behind the Veil of Ignorance - How Risk Averse do you have to be to Prefer Europe over the US?

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    The paper uses a veil of ignorance approach and income distribution data of developed countries to arrive at inequality corrected income rankings. While a risk neutral individual (based on year 2000 data) would have preferred to be born into the US rather than any European country in our sample except Luxembourg, a coefficient of relative risk aversion of 2 suffices to make several European countries look preferable. The paper also sheds light on the risk corrected average income on a gender basis and scans for times of diminished expectations, i.e. periods where the expected utility of being born into a country has reduced over time.income distribution, veil of ignorance, cross country comparison
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