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991.
992.
Christian Holmgren Louise Cornmark Gry Kalstad Lønne Katarzyna Chmielarska Masoumi Christer Larsson 《BMC biochemistry》2016,17(1):11
Background
Protein kinase C δ (PKCδ) is known to be an important regulator of apoptosis, having mainly pro- but also anti-apoptotic effects depending on context. In a previous study, we found that PKCδ interacts with the pro-apoptotic protein Smac. Smac facilitates apoptosis by suppressing inhibitor of apoptosis proteins (IAPs). We previously established that the PKCδ-Smac complex dissociates during induction of apoptosis indicating a functional importance. Because the knowledge on the molecular determinants of the interaction is limited, we aimed at characterizing the interactions between PKCδ and Smac.Results
We found that PKCδ binds directly to Smac through its regulatory domain. The interaction is enhanced by the PKC activator TPA and seems to be independent of PKCδ catalytic activity since the PKC kinase inhibitor GF109203X did not inhibit the interaction. In addition, we found that C1 and C2 domains from several PKC isoforms have Smac-binding capacity.Conclusions
Our data demonstrate that the Smac-PKCδ interaction is direct and that it is facilitated by an open conformation of PKCδ. The binding is mediated via the PKCδ regulatory domain and both the C1 and C2 domains have Smac-binding capacity. With this study we thereby provide molecular information on an interaction between two apoptosis-regulating proteins.993.
A generic type age‐structured fishery population model consisting of two harvestable age classes is formulated. Optimal harvest rates are determined with uniform fishing mortality and perfectly selective fishing, respectively. Selectivity allows for differentiating the fishing mortality among different age classes. Sustainable yield–biomass functions are developed, and the maximum sustainable yield (MSY) solutions are found under both exploitation schemes. The gain of perfectly selective fishing over uniform (or biomass) fishing is examined under various assumptions, and it is proved that the benefit of selective harvesting increases when the harvestable fish population becomes more heterogeneous in terms of weights, or values. In contrast to the surplus production model, or Clark model, the analysis also demonstrates that MSY with different age classes is not purely a biological concept. 相似文献
994.
Andersson K Ketteler G Bluhm H Yamamoto S Ogasawara H Pettersson LG Salmeron M Nilsson A 《Journal of the American Chemical Society》2008,130(9):2793-2797
Autocatalytic dissociation of water on the Cu(110) metal surface is demonstrated on the basis of X-ray photoelectron spectroscopy studies carried out in situ under near ambient conditions of water vapor pressure (1 Torr) and temperature (275-520 K). The autocatalytic reaction is explained as the result of the strong hydrogen-bond in the H2O-OH complex of the dissociated final state, which lowers the water dissociation barrier according to the Br?nsted-Evans-Polanyi relations. A simple chemical bonding picture is presented which predicts autocatalytic water dissociation to be a general phenomenon on metal surfaces. 相似文献
995.
Vigren E Kamińska M Hamberg M Zhaunerchyk V Thomas RD Danielsson M Semaniak J Andersson PU Larsson M Geppert WD 《Physical chemistry chemical physics : PCCP》2008,10(27):4014-4019
The dissociative recombination of fully deuterated protonated acetonitrile, CD(3)CND(+), has been investigated at the CRYRING heavy ion storage ring, located at the Manne Siegbahn Laboratory, Stockholm, Sweden. Branching fractions were measured at approximately 0 eV relative collision energy between the ions and the electrons and in 65% of the DR events there was no rupture of bonds between heavy atoms. In the remaining 35%, one of the bonds between the heavy atoms was broken. The DR cross-section was measured between approximately 0 eV and 1 eV relative collision energy. In the energy region between 1 meV and 0.1 eV the cross section data were best fitted by the expression sigma = 7.37 x 10(-16) (E/eV)(-1.23) cm(2), whereas sigma = 4.12 x 10(-16) (E/eV)(-1.46) cm(2) was the best fit for the energy region between 0.1 and 1.0 eV. From the cross section a thermal rate coefficient of alpha(T) = 8.13 x 10(-7) (T/300)(-0.69) cm(3) s(-1) was deduced. 相似文献
996.
Gannon G Larsson JA Greer JC Thompson D 《The journal of physical chemistry. B》2008,112(30):8906-8911
Solutions containing guanidinium chloride (GdmCl), or equivalently guanidine hydrochloride (GdnHCl), are commonly used to denature macromolecules such as proteins and DNA in, for example, microfluidics studies of protein unfolding. To design and study such applications, it is necessary to know the diffusion coefficients for GdmCl in the solution. To this end, we use molecular dynamics simulations to calculate the diffusion coefficients of GdmCl in water and in water-ethanol solutions, for which no direct experimental measurements exist. The fully atomistic simulations show that the guandinium cation Gdm (+) diffusion decreases as the concentration of both Gdm (+) and ethanol in the solution increases. The simulations are validated against available literature data, both transformed measured viscosity values and computed diffusion coefficients, and we show that a prudent choice of water model, namely TIP4P-Ew, gives calculated diffusion coefficients in good agreement with the transformed measured viscosity values. The calculated Gdm (+) diffusion behavior is explained as a dynamic mixture of free cation, stacked cation, and ion-paired species in solution, with weighted contributions to Gdm (+) diffusion from the stacked and paired states helping explain measured viscosity data in terms of atom-scale dynamics. 相似文献
997.
Dauphin Y Ball AD Cotte M Cuif JP Meibom A Salomé M Susini J Williams CT 《Analytical and bioanalytical chemistry》2008,390(6):1659-1669
A microstructural, mineralogical, and chemical study of the nacre–prisms boundary in the shells of Pinctada margaritifera shows that this boundary is not an abrupt transition, but that there exists a distinct fibrous layer with clear topographic
structures and evidence of growth lines. A three-step biomineralization process is proposed that involves changes in the chemical
and biochemical composition of the last growth increments of the calcite prisms, formation of the fibrous layer, and development
of regular tablets in the nacreous layer. 相似文献
998.
Three different SPE sorbents (weak cation exchange, mixed cation exchange, and hydrophobic-lipophilic balance polymers) were compared in terms of recovery, precision, and the effect of matrix components on analyte response for the determination of fluoroquinolones antibiotics. The influence of ethylenediaminetetraacetic acid disodium salt (Na2-EDTA) was as well tested. Two of the sorbents, hydrophilic-lipophilic balance (HLB) and weak cation exchange (WCX), turned out to be suitable for ultratrace analysis. HLB sorbent showed higher capacity for analyte trapping and better precision while weak cation exchange sorbent had a superior performance in terms of selectivity. In complex samples, the higher capacity of HLB was outweighed by the higher selectivity of WCX when considering the LODs of the methods. 相似文献
999.
The strontium content of serum, bone, marrow, and teeth was determined by inductively-coupled plasma mass spectrometry (ICP–MS).
Significant correlations were obtained after the data were subjected to quality assurance (QA) performed according to validated
procedures. After four weeks of treatment with strontium malonate, strontium levels increased from 76 ± 9 μg g−1 in placebo-treated dogs to levels of 7.2 ± 1.7 mg g−1, 9.5 ± 2.7 mg g−1, and 9.8 ± 2.7 mg g−1 in groups treated with 300, 1000, and 3000 mg kg−1 day−1, respectively. Strontium induced a highly significant increase in the bone formation marker, bone-specific alkaline phosphatase
(BSAP), and an excellent correlation was found with the bone-strontium content. In females, the placebo-treated group showed
a decrease in BSAP of 53%, whereas the three strontium malonate-treated groups showed an increase of 60, 276, and 278% for
the groups treated with 300, 1000, and 3000 mg kg−1 day−1, respectively. For males the corresponding values were −44%, +142%, +194%, and +247% increases in BSAP in the placebo, 300,
1000, and 3000 mg kg−1 day−1 groups respectively. 相似文献
1000.
Anders C. Hansen 《Journal of Functional Analysis》2008,254(8):2092-2126
We present several new techniques for approximating spectra of linear operators (not necessarily bounded) on an infinite-dimensional, separable Hilbert space. Our approach is to take well-known techniques from finite-dimensional matrix analysis and show how they can be generalized to an infinite-dimensional setting to provide approximations of spectra of elements in a large class of operators. We conclude by proposing a solution to the general problem of approximating the spectrum of an arbitrary bounded operator by introducing the n-pseudospectrum and argue how that can be used as an approximation to the spectrum. 相似文献