1,359 research outputs found

    The Rhetorical Implications of Clementia in Cicero’s Caesarian Speeches

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    Cicero’s Caesarian speeches were delivered in 46-45 B.C. to Caesar after his victories in the Civil War. Caesar faced a number of critical issues as he dealt with the political and social aftermath of the years after 49 B.C., including what to do with the supporters of his enemies. Cicero, preeminent orator and a key political, was well-placed to speak on behalf of these individuals. Clementia, as an intrinsic theme, impinges upon social, political, and linguistic spheres and became a nexus for anxieties and manipulation between the senatorial and plebian orders. This research compares and contrasts the understanding, presentation, and use of clementia in these speeches, in a discussion set within the social, political, and linguistic contexts that lend this word its powerful significance. It is clear that clementia becomes a point of negotiation of power for Caesar and Cicero alike, the one asserting his political dominance, the other speaking as the social conscience of Rome

    The Motives for Moral Credit

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    To deserve credit for doing what is morally right, we must act from the right kinds of motives. Acting from the right kinds of motives involves responding both to the morally relevant reasons, by acting on these considerations, and to the morally relevant individuals, by being guided by appropriate attitudes of regard for them. Recent theories of the right kinds of motives have tended to prioritize responding to moral reasons. I develop a theory that instead prioritizes responding to individuals (through appropriate attitudes of regard for them) and argue that it better accounts for the basic features of the right kinds of motives – what we most fundamentally care about in judging whether persons deserve moral credit

    The prognostic value of cortical magnetic stimulation in acute middle cerebral artery infarction compared to other parameters

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    The prognostic value of magnetic evoked potentials (MEP), somatosensory evoked potentials (SSEP), age and radiological parameters was determined in 50 patients with acute middle cerebral artery infarction. We performed MEP and SSEP within 4 days and after 6 weeks and 3 months of the infarction and assessed clinical improvement by using the Barthel index (BI) and the Rankin scale. The localization and extent of the infarction was investigated by CT scanning or NMR. All parameters were correlated to clinical outcome and the prognostic significance of each parameter in addition to BI was determined. MEP, SSEP, and age were valuable prognostic parameters in predicting stroke outcome when used together with the BI. However, in stepwise regression analysis using all parameters simultaneously, only MEP and age significantly contributed to clinical outcome in addition to BI. Patients showed a better outcome when their MEP was normal or delayed, measured within 4 days of the infarction, compared to patients with absent MEP. Clinical outcome was better at a younger age

    CONTRACT FINISHING FOR NEW ENTRANTS IN PORK PRODUCTION

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    The pork production industry is a far different industry today than it was fifty, twenty, or even five years ago. On diversified Midwestern farms during the mid-to-late 20th century, the swine enterprise was labeled "the mortgage lifter". The hogs added value to home-produced feedstuffs such as corn and increased the income from a given acreage base. As farm mechanization and technology rapidly developed, farms became larger and less diversified as livestock disappeared from many farmsteads. In this paper, we address the question whether swine units can be introduced to non-livestock farms via a coordinated agreement for the grower-finisher phase and make these farms more profitable. To do this, we first describe some of the changes that have taken place in the pork industry. Second, production contracts and grower payments are introduced. Next, we move on to issues of manure management and the value of manure to non-livestock farms. Finally, in the Appendix, financial analyses for sample contract finishing contracts are laid out to help farmers determine if contract finishing could benefit their farming operations.Livestock Production/Industries,

    The remote substrate binding subsite-6 in cyclodextrin-glycosyltransferase controls the transferase activity of the enzyme via an induced-fit mechanism

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    Cyclodextrin-glycosyltransferase (CGTase) catalyzes the formation of alpha-, beta-, and gamma-cyclodextrins (cyclic alpha-(1,4)-linked oligosaccharides of 6, 7, or 8 glucose residues, respectively) from starch. Nine substrate binding subsites were observed in an x-ray structure of the CGTase from Bacillus circulans strain 251 complexed with a maltononaose substrate. Subsite -6 is conserved in CGTases, suggesting its importance for the reactions catalyzed by the enzyme. To investigate this in detail, we made six mutant CGTases (Y167F, G179L, G180L, N193G, N193L, and G179L/G180L). All subsite -6 mutants had decreased k(cat) values for beta-cyclodextrin formation, as well as for the disproportionation and coupling reactions, but not for hydrolysis. Especially G179L, G180L, and G179L/G180L affected the transglycosylation activities, most prominently for the coupling reactions. The results demonstrate that (i) subsite -6 is important for all three CGTase-catalyzed transglycosylation reactions, (ii) Gly-180 is conserved because of its importance for the circularization of the linear substrates, (iii) it is possible to independently change cyclization and coupling activities, and (iv) substrate interactions at subsite -6 activate the enzyme in catalysis via an induced-fit mechanism. This article provides for the first time definite biochemical evidence for such an induced-fit mechanism in the alpha-amylase family

    Crystallographic and Fluorescence Studies of the Interaction of Haloalkane Dehalogenase with Halide Ions. Studies with Halide Compounds Reveal a Halide Binding Site in the Active Site

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    Haloalkane dehalogenase from Xanthobacter autotrophicus GJ10 catalyzes the conversion of 1,2-dichloroethane to 2-chloroethanol and chloride without use of oxygen or cofactors. The active site is situated in an internal cavity, which is accesible from the solvent, even in the crystal. Crystal structures of the dehalogenase enzyme complexed with iodoacetamide, chloroacetamide, iodide, and chloride at pH 6.2 and 8.2 revealed a halide binding site between the ring NH's of two tryptophan residues, Trp-125 and Trp-175, located in the active site. The halide ion lies on the intersection of the planes of the rings of the tryptophans. The binding of iodide and chloride to haloalkane dehalogenase caused a strong decrease in protein fluorescence. The decrease could be fitted to a modified form of the Stern-Volmer equation, indicating the presence of fluorophors of different accessibilities. Halide binding was much stronger at pH 6.0 than at pH 8.2. Assuming ligand binding to Trp-125 and Trp-175 as the sole cause of fluorescence quenching, dissociation constants at pH 6.0 with chloride and iodide were calculated to be 0.49 +/- 0.04 and 0.074 +/- 0.007 mM, respectively. Detailed structural investigation showed that the halide binding site probably stabilizes the halide product as well as the negatively charged transition state occurring during the formation of the covalent intermediate

    Site-Directed Mutations in Tyrosine 195 of Cyclodextrin Glycosyltransferase from Bacillus circulans Strain 251 Affect Activity and Product Specificity

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    Tyrosine 195 is located in the center of the active site cleft of cyclodextrin glycosyltransferase (EC 2.4.1.19) from Bacillus circulans strain 251. Alignment of amino acid sequences of CGTases and alpha-amylases, and the analysis of the binding mode of the substrate analogue acarbose in the active site cleft [Strokopytov, B., et al. (1995) Biochemistry 34, (in press)], suggested that Tyr195 plays an important role in cyclization of oligosaccharides. Tyr195 therefore was replaced with Phe (Y195F), Trp (Y195W), Leu (Y195L), and Gly (Y195G). Mutant proteins were purified and crystallized, and their X-ray structures were determined at 2.5-2.6 Angstrom resolution, allowing a detailed comparison of their biochemical properties and three-dimensional structures with those of the wild-type CGTase protein. The mutant proteins possessed significantly reduced cyclodextrin forming and coupling activities but were not negatively affected in the disproportionation and saccharifying reactions. Also under production process conditions, after a 45 h incubation with a 10% starch solution, the Y195W, Y195L, and Y195G mutants showed a lower overall conversion of starch into cyclodextrins. These mutants produced a considerable amount of linear maltooligosaccharides. The presence of aromatic amino acids (Tyr or Phe) at the Tyr195 position thus appears to be of crucial importance for an efficient cyclization reaction, virtually preventing the formation of linear products. Mass spectrometry of the Y195L reaction mixture, but not that of the other mutants and the wild type, revealed a shift toward the synthesis (in low yields) of larger products, especially of beta- and gamma- (but no alpha-) cyclodextrins and minor amounts of delta-, epsilon-, zeta- and eta-cyclodextrins. This again points to an important role for the residue at position 195 in the formation of cyclic products

    Interaction of swine nursery and grow-finish space allocations on performance

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    Two experiments were conducted to evaluate the possible interaction of nursery space allocations and grow-finish space allocations in swine. In Exp. 1, crowding was achieved by varying the number of pigs per pen. During the nursery phase, decreasing the space allocation (0.16 m2/pig vs 0.25 m2/pig; 8 and 12 pens per treatment, respectively) by increasing the number of pigs per pen (18 vs 12) resulted in a decrease in daily feed intake (0.609 vs 0.683 kg/d; P \u3c 0.001) and daily gain (0.364 vs 0.408 kg/d; P \u3c 0.001). Pigs were mixed within nursery treatment groups and reassigned to grow-finish pens (6 pens per treatment) at the end of the 35-d nursery period providing either 0.56 m2/pig (14 pigs/pen) or 0.78 m2/pig (10 pigs/pen). Crowding during the grow-finish phase decreased daily feed intake (P \u3c 0.003) and daily gain (P \u3c 0.001). In Exp. 2, space allocations of 0.16 m2/pig vs 0.23 m2/pig during the nursery phase (24 pens per treatment) resulted in a decrease in daily feed intake (0.612 vs 0.654 kg/d; P \u3c 0.005) and daily gain (0.403 vs 0.430 kg/d; P \u3c 0.001). Pigs remained in the same (social) groups when moved to the grow-finish phase. Unlike Exp. 1, there was no effect of crowding during the grow-finish phase (0.60 m2/pig vs 0. 74 m2/pig) on daily feed intake or daily gain. The difference in results between experiments suggests that the response to crowding during the grow-finish phase may depend in part on whether pigs are mixed and sorted following movement from the nursery

    Three-dimensional Structure of L-2-Haloacid Dehalogenase from Xanthobacter autotrophicus GJ10 Complexed with the Substrate-analogue Formate

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    The L-2-haloacid dehalogenase from the 1,2-dichloroethane degrading bacterium Xanthobacter autotrophicus GJ10 catalyzes the hydrolytic dehalogenation of small L-2-haloalkanoic acids to yield the corresponding D-2-hydroxyalkanoic acids. Its crystal structure was solved by the method of multiple isomorphous replacement with incorporation of anomalous scattering information and solvent flattening, and was refined at 1.95-Å resolution to an R factor of 21.3%. The three-dimensional structure is similar to that of the homologous L-2-haloacid dehalogenase from Pseudomonas sp. YL (1), but the X. autotrophicus enzyme has an extra dimerization domain, an active site cavity that is completely shielded from the solvent, and a different orientation of several catalytically important amino acid residues. Moreover, under the conditions used, a formate ion is bound in the active site. The position of this substrate-analogue provides valuable information on the reaction mechanism and explains the limited substrate specificity of the Xanthobacter L-2-haloacid dehalogenase.

    X-ray structure of bovine pancreatic phospholipase A(2) at atomic resolution

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    Using synchrotron radiation and a CCD camera, X-ray data have been collected from wild-type bovine pancreatic phospholipase A(2) at 100 K to 0.97 Angstrom resolution allowing full anisotropic refinement. The final model has a conventional R factor of 9.44% for all reflections, with a mean standard uncertainty for the positional parameters of 0.031 Angstrom as calculated from inversion of the full positional least-squares matrix. At 0.97 Angstrom resolution, bovine pancreatic phospholipase A(2) reveals for the first time that its rigid scaffolding does not preclude flexibility, which probably plays an important role in the catalytic process. Functionally important regions (the interfacial binding site and calcium-binding loop) are located at the molecular surface, where conformational variability is more pronounced. A cluster of 2-methyl-2,4-pentanediol molecules is present at the entrance of the hydrophobic channel that leads to the catalytic site and mimics the fatty-acid chains of a substrate analogue. Bovine pancreatic phospholipase A(2) at atomic resolution is compared with previous crystallographic structures and with models derived from nuclear magnetic resonance studies. Given the high structural similarity among extracellular phospholipases A(2) observed so far at lower resolution, the results arising from this structural analysis are expected to be of general validity for this class of enzymes
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