138 research outputs found

    Studies on the structure of hair-forming groups in Finnsheep

    Get PDF
    Recognition of hair-forming groups in the skin of sheep was dealt with by many scientists on almost all breeds of sheep in the world and in some particular countries. To the few breeds not yet investigated up to now in this respect belongs Finnsheep (F), and this substantiates the present attempt. The histological analysis was performed on skin sections taken by the biopsy method from 7 F of the Experiment Station Koluda Wielka. Upon fixing and staining skin preparations by the method generally applied, the microscopic examination of kinds of groups, number of primary (P) and secondary(S) follicles per 1 mm2 (nS/mm2 +nP/mm2) in all kinds of groups as well as density of follicles, i.e.nS/nP per 1 mm2, was carried out. In microscopic pictures of skin, documented by means of photographs, superiority of triple groups, the share of which amounted to 74.2 %, has been found. The share of quadruple groups was 11.4 %, of double groups 8.6 % and of hexal groups 5.1 %. The mean density of follicles, measured by the number of primary and secondary follicles per 1mm2 of skin, amounts to 14.1, which results from the share of 2.0 primary + 12.2 secondary follicles per 1 mm2. The value of the nS/nP ratio in particular groups was as follows: the highest ratio was for the triple group (6.0), in the double group it amounted to 5.8, in quadruple group to 5.6 and in the hexal group to 5.3. Thus, the mean density for this sheep breed amounts to 5.84. Differences in the above values between singles and groups appeared to be small and not proved statistically. The obtained results concerning the studied F skin traits are characteristics for the hair cover of longwoolled type

    Protein kinase C α and ε phosphorylation of troponin and myosin binding protein C reduce Ca2+ sensitivity in human myocardium

    Get PDF
    Previous studies indicated that the increase in protein kinase C (PKC)-mediated myofilament protein phosphorylation observed in failing myocardium might be detrimental for contractile function. This study was designed to reveal and compare the effects of PKCα- and PKCε-mediated phosphorylation on myofilament function in human myocardium. Isometric force was measured at different [Ca2+] in single permeabilized cardiomyocytes from failing human left ventricular tissue. Activated PKCα and PKCε equally reduced Ca2+ sensitivity in failing cardiomyocytes (ΔpCa50 = 0.08 ± 0.01). Both PKC isoforms increased phosphorylation of troponin I- (cTnI) and myosin binding protein C (cMyBP-C) in failing cardiomyocytes. Subsequent incubation of failing cardiomyocytes with the catalytic subunit of protein kinase A (PKA) resulted in a further reduction in Ca2+ sensitivity, indicating that the effects of both PKC isoforms were not caused by cross-phosphorylation of PKA sites. Both isozymes showed no effects on maximal force and only PKCα resulted in a modest significant reduction in passive force. Effects of PKCα were only minor in donor cardiomyocytes, presumably because of already saturated cTnI and cMyBP-C phosphorylation levels. Donor tissue could therefore be used as a tool to reveal the functional effects of troponin T (cTnT) phosphorylation by PKCα. Massive dephosphorylation of cTnT with alkaline phosphatase increased Ca2+ sensitivity. Subsequently, PKCα treatment of donor cardiomyocytes reduced Ca2+ sensitivity (ΔpCa50 = 0.08 ± 0.02) and solely increased phosphorylation of cTnT, but did not affect maximal and passive force. PKCα- and PKCε-mediated phosphorylation of cMyBP-C and cTnI as well as cTnT decrease myofilament Ca2+ sensitivity and may thereby reduce contractility and enhance relaxation of human myocardium

    Enzyme Promiscuity in Enolase Superfamily. Theoretical Study of o-Succinylbenzoate Synthase Using QM/MM Methods

    Get PDF
    The promiscuous activity of the enzyme o-succinylbenzoate synthase (OSBS) from the actinobacteria Amycolatopsis is investigated by means of QM/MM methods, using both density functional theory and semiempirical Hamiltonians. This enzyme catalyzes not only the dehydration of 2-succinyl-6R-hydroxy-2,4-cyclohexadiene-1R-carboxylate but also catalyzes racemization of different acylamino acids, with N-succinyl-R-phenylglycine being the best substrate. We investigated the molecular mechanisms for both reactions exploring the potential energy surface. Then, molecular dynamics simulations were performed to obtain the free energy profiles and the averaged interaction energies of enzymatic residues with the reacting system. Our results confirm the plausibility of the reaction mechanisms proposed in the literature, with a good agreement between theoretical and experimentally derived activation free energies. Our simulations unravel the role played by the different residues in each of the two possible reactions. The presence of flexible loops in the active site and the selection of structural modifications in the substrate seem to be key elements to promote the promiscuity of this enzyme.This work was supported by the Spanish Ministerio de Economia y Competitividad project CTQ2012-36253-C03-03 ́ and FEDER funds. K.S. thanks the Polish National Science Center (NCN) for Grant 2011/02/A/ST4/00246. The authors acknowledge computational facilities of the Servei d’Informatica ̀ de la Universitat de Valencia in the ̀ “Tirant” supercomputer, which is part of the Spanish Supercomputing Network

    Transcendental-Phenomenological Proof and Descriptive Metaphysics

    Get PDF
    Following P.F. Strawson's reading of Kant, the majority of the literature on transcendental arguments seeks to divorce such arguments from their original Kantian context. This thesis is concerned with Mark Sacks's recent defence of transcendental arguments, which takes a different approach. A critique is given of Sacks's work and extensions and modifications of his approach are recommended. It is proposed that certain difficulties encountered by Kant's transcendentally-ideal approach can be overcome with Hegelian solutions

    Studies on the structure of hair-forming groups in Finnsheep

    No full text
    vokkirjasto Aj-

    Thermal analysis of polysynthetic basic oils

    No full text
    corecore