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91.
Rasmus Skern-Mauritzen Petter Frost Sussie Dalvin Bj?rn Olav Kvamme Ingunn Sommerset Frank Nilsen 《BMC molecular biology》2009,10(1):44
Background
Trypsin-like serine proteases are involved in a large number of processes including digestive degradation, regulation of developmental processes, yolk degradation and yolk degradome activation. Trypsin like peptidases considered to be involved in digestion have been characterized in Lepeophtheirus salmonis. During these studies a trypsin-like peptidase which differed in a number of traits were identified. 相似文献92.
93.
PELDOR (or DEER; pulsed electron-electron double resonance) is an EPR (electron paramagnetic resonance) method that measures via the dipolar electron-electron coupling distances in the nanometre range, currently 1.5-8 nm, with high precision and reliability. Depending on the quality of the data, the error can be as small as 0.1 nm. Beyond mere mean distances, PELDOR yields distance distributions, which provide access to conformational distributions and dynamics. It can also be used to count the number of monomers in a complex and allows determination of the orientations of spin centres with respect to each other. If, in addition to the dipolar through-space coupling, a through-bond exchange coupling mechanism contributes to the overall coupling both mechanisms can be separated and quantified. Over the last 10 years PELDOR has emerged as a powerful new biophysical method without size restriction to the biomolecule to be studied, and has been applied to a large variety of nucleic acids as well as proteins and protein complexes in solution or within membranes. Small nitroxide spin labels, paramagnetic metal ions, amino acid radicals or intrinsic clusters and cofactor radicals have been used as spin centres. 相似文献
94.
Small diameter transosseous wires are main parts of the Ilizarov frame concept. Wire tensioning is essential to gain the necessary transversal stiffness, and the wire fixators are therefore important, coupling the wire to the ring. The ability of three different wire fixator designs to maintain wire tension under dynamic loading is described. The three fixator designs were combinations of two types of bolts and one washer. In a simplified frame set-up consisting of one ring and one wire, sixty wires were dynamically loaded in sequence with 200N for 450 times and wire tension was repeatedly measured. The tension loss employing the different fixator types at two wire pretension levels (883N, 1275N) was measured. Wire slippage in the fixators and the midpoint deflection angle of the wires were measured. Large differences in fixation ability were observed. Wire fixators holding a larger and rougher contact surface had significant smaller tension loss compared to fixators with a smaller and smother contact surface. Both plastic wire deformation and slippage causes tension loss with slippage as the main contributor. Wire fixators' design can be improved in order to maintain wire tension. Such improvement could be of clinical interest enhancing the mechanical stability of the fixator. 相似文献
95.
Trautsch J Rosseland BO Pedersen SA Kristiansen E Zachariassen KE 《Journal of insect physiology》2011,57(8):1123-1126
As the body fluid of freeze-tolerant organisms freezes, solutes become concentrated in the gradually smaller unfrozen fluid fraction, and dissolved trace metals may reach toxic levels. A dialysis technique was used to investigate the metal binding capacity of the low density fraction of the hemolymph from the freeze tolerant beetle Phyto depressus. The low density fraction, assumed to contain the ice nucleating lipoproteins, showed approximately 100 times greater capacity to bind metals (Cd 2+, Cu 2+ and Zn 2+) than the proteins albumin, hemoglobin and similar to metallothionein. The high metal binding capacity in the low density fraction raises the question if the ice nucleating lipoproteins might assist in detoxification of potentially toxic concentrations of metals that may occur when a large fraction of the bodyfluids of freeze tolerant insects freeze. This hypotheis is consistent with the fact that the lipoprotein ice nucleators are present in far greater amounts than required for ice nucleation, and also with the fact that the lipoprotein ice nucleators have a remarkably high content of amino acids with negatively charged residues that may act as metal binding sites. 相似文献
96.
Maiko Mori Marie Smedberg Maria Klaude Inga Tj?der ?ke Norberg Olav Rooyackers Jan Wernerman 《PloS one》2014,9(5)
Glutamine transport between tissues is important for the outcome of critically ill patients. Investigation of glutamine kinetics is, therefore, necessary to understand glutamine metabolism in these patients in order to improve future intervention studies. Endogenous glutamine production can be measured by continuous infusion of a glutamine tracer, which necessitates a minimum measurement time period. In order to reduce this problem, we used and validated a tracer bolus injection method. Furthermore, this method was used to measure the glutamine production in healthy volunteers in the post-absorptive state, with extra alanine and with glutamine supplementation and parenteral nutrition. Healthy volunteers received a bolus injection of [1-13C] glutamine, and blood was collected from the radial artery to measure tracer enrichment over 90 minutes. Endogenous rate of appearance (endoRa) of glutamine was calculated from the enrichment decay curve and corrected for the extra glutamine supplementation. The glutamine endoRa of healthy volunteers was 6.1±0.9 µmol/kg/min in the post-absorptive state, 6.9±1.0 µmol/kg/min with extra alanyl-glutamine (p = 0.29 versus control), 6.1±0.4 µmol/kg/min with extra alanine only (p = 0.32 versus control), and 7.5±0.9 µmol/kg/min with extra alanyl-glutamine and parenteral nutrition (p = 0.049 versus control). In conclusion, a tracer bolus injection method to measure glutamine endoRa showed good reproducibility and small variation at baseline as well as during parenteral nutrition. Additionally, we showed that parenteral nutrition including alanyl-glutamine increased glutamine endoRa in healthy volunteers, which was not attributable to the alanine part of the dipeptide. 相似文献
97.
Jacob M?rup Schlütter Ida Kirkegaard Olav Bj?rn Petersen Nanna Larsen Britta Christensen David M. Hougaard Steen K?lvraa Niels Uldbjerg 《PloS one》2014,9(9)
Objective
To identify factors influencing the number of fetal cells in maternal blood.Methods
A total of 57 pregnant women at a gestational age of weeks 11–14 were included. The number of fetal cells in maternal blood was assessed in 30 ml of blood using specific markers for both enrichment and subsequent identification.Results
Participants carrying male fetuses had a higher median number of fetal cells in maternal blood than those carrying female fetuses (5 vs. 3, p = 0.04). Certain cytokines (RANTES, IL-2 and IL-5) were significantly associated with the number of fetal cells in maternal blood.Conclusion
The number of fetal cells in maternal blood is associated with certain cytokines and fetal gender. 相似文献98.
99.
Edith Buchinger Daniel H. Knudsen Manja A. Behrens Jan Skov Pedersen Olav A. Aarstad Anne T?ndervik Svein Valla Gudmund Skj?k-Br?k Reinhard Wimmer Finn L. Aachmann 《The Journal of biological chemistry》2014,289(45):31382-31396
The bacterium Azotobacter vinelandii produces a family of seven secreted and calcium-dependent mannuronan C-5 epimerases (AlgE1–7). These epimerases are responsible for the epimerization of β-d-mannuronic acid (M) to α-l-guluronic acid (G) in alginate polymers. The epimerases display a modular structure composed of one or two catalytic A-modules and from one to seven R-modules having an activating effect on the A-module. In this study, we have determined the NMR structure of the three individual R-modules from AlgE6 (AR1R2R3) and the overall structure of both AlgE4 (AR) and AlgE6 using small angle x-ray scattering. Furthermore, the alginate binding ability of the R-modules of AlgE4 and AlgE6 has been studied with NMR and isothermal titration calorimetry. The AlgE6 R-modules fold into an elongated parallel β-roll with a shallow, positively charged groove across the module. Small angle x-ray scattering analyses of AlgE4 and AlgE6 show an overall elongated shape with some degree of flexibility between the modules for both enzymes. Titration of the R-modules with defined alginate oligomers shows strong interaction between AlgE4R and both oligo-M and MG, whereas no interaction was detected between these oligomers and the individual R-modules from AlgE6. A combination of all three R-modules from AlgE6 shows weak interaction with long M-oligomers. Exchanging the R-modules between AlgE4 and AlgE6 resulted in a novel epimerase called AlgE64 with increased G-block forming ability compared with AlgE6. 相似文献
100.