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1.
Chitinase was purified from the culture medium of Bacillus licheniformis SK-1 by colloidal chitin affinity adsorption followed by diethylamino ethanol-cellulose column chromatography. The purified
enzyme showed a single band on sodium dodecyl sulfate polyacrylamide gel electrophoresis. The molecular size and pI of chitinase 72 (Chi72) were 72 kDa and 4.62 (Chi72) kDa, respectively. The purified chitinase revealed two activity optima
at pH 6 and 8 when colloidal chitin was used as substrate. The enzyme exhibited activity in broad temperature range, from
40 to 70°C, with optimum at 55°C. It was stable for 2 h at temperatures below 60°C and stable over a broad pH range of 4.0–9.0
for 24 h. The apparent K
m and V
max of Chi72 for colloidal chitin were 0.23 mg ml−1 and 7.03 U/mg, respectively. The chitinase activity was high on colloidal chitin, regenerated chitin, partially N-acetylated chitin, and chitosan. N-bromosuccinamide completely inhibited the enzyme activity. This enzyme should be a good candidate for applications in the
recycling of chitin waste. 相似文献
2.
D Koylu S Sarrafpour J Zhang S Ramjattan MJ Panzer SW Thomas Iii 《Chemical communications (Cambridge, England)》2012,48(76):9489-9491
This paper describes thin films comprising acenes dispersed in a conjugated polymeric host that have a ratiometric photoluminescence response to singlet oxygen. These films also respond to irradiation of protein-bound sensitizers, which represents a solution to the problem of protein-conjugated polymer non-specific interactions. 相似文献
3.
M. Sanderova K. Sandera V. Stehlik K. Gandera L. Sattler J. E. Mull I. Lorge I. Sorgato F. Pridal A. Conlin C. Smolenski T. Pietrzykowski V. Dejmek F. Stern F. Kryz R. Ofner W. R. Fetzer J. W. Evans W. Z. Hassid M. Nurmia F. W. Zerban W. J. Hughes M. H. Wiley J. N. Taran Mary Scott E. S. West E. Roboz G. Vavrinecz M. Nordlund D. A. Magraw C. W. Sievert F. Massa M. Kminek S. Sanya H. Riehm H. C. S. de Whalley Ö. Fernández M. de Mingo G. Oschmjan M. Kudrjawzewa W. B. Sinclair E. T. Bartholomew K. P. Jácobsohn J. Mayrhofer E. Jekel A. Josz S. Molirískij 《Analytical and bioanalytical chemistry》1937,108(11-12):445-455
4.
Gaussian modifications of the neutrino energy loss (NEL) by electron capture on the strongly screening nuclides 55Co and 56Ni are investigated. The results show that in strong electron screening (SES), the NEL rates decrease without modifying the Gamow-Teller (G-T) resonance transition. For instance, the NEL rates of 55Co and 56Ni decrease more than two and three orders of magnitude for ρ7=5.86, T9≤5, Ye=0.47, Δ=6.3, respectively. In contrast, due to Gaussian modification, the NEL rates increase about two orders of magnitude in SES. Due to SES, the maximum values of the C-factor (in %) on NEL of 55Co, 56Ni are of the order of 99.80%, 99.56% at ρ7=5.86 Ye=0.47 and 99.60%, 99.65% at ρ7=106 Ye=0.43, respectively. 相似文献
5.
Microbubble mediated sonoporation of cells in suspension: Clonogenic viability and influence of molecular size on uptake 总被引:1,自引:0,他引:1
This work investigates whether the application of sonoporation is limited by the size of a macromolecule being delivered and by the ability of cells to proliferate following uptake. KHT-C cells in suspension were exposed to variations in ultrasound pressure (0-570 kPa) and microbubble shell-type (lipid and protein) at fixed settings of 500 kHz centre frequency, 32 μs pulse duration, 3 kHz pulse repetition frequency and 2 min insonation. Reversible permeability (PR), defined as the number of cells stained with FITC-dextran and unstained with propidium iodide (i.e., PI-viable), was measured with flow cytometry for marker molecules ranging from 10 kDa to 2 MDa in size. Viable permeability (PV) defined as the number of permeabilised cells that maintained their ability to proliferate, was measured by clonogenic assay. Comparable intracellular delivery of all sizes of molecules was achieved, indicating that intracellular delivery of common therapeutic drugs may not be limited by molecular size. Maximum PR’s of 80% (at 10 kDa) and 55% (at 10 kDa) were achieved with lipid coated bubbles at 3.3% v/v and protein coated bubbles at 6.7% v/v concentrations. The PI-viability was approximately 80% at 570 kPa in both cases. The maximum PV achieved with both agents was 22%, while inducing a lower overall clonogenic viability with the lipid (39%) compared to the protein (56%) shelled bubbles. This study demonstrates that large macromolecules, up to 2 MDa in size, can be delivered with high efficiency to cells which undergo reversible permeabilisation, maintaining long-term viability in approximately half of the cells. 相似文献
6.
Tornøe CW Sanderson SJ Mottram JC Coombs GH Meldal M 《Journal of combinatorial chemistry》2004,6(3):312-324
A library consisting of about half of 800 000 possible peptidotriazoles on 450 000 beads was prepared by solid-phase peptide synthesis combined with a regiospecific copper(I)-catalyzed 1,3-dipolar cycloaddition between a resin-bound alkyne and a protected amino azide. The central [1,2,3]-triazole was flanked on each side by two randomized amino acids introduced in a combinatorial approach. Importantly, the formation of the triazole could be performed quantitatively in a randomized fashion. The library was screened on solid phase for inhibitory effect against a recombinant cysteine protease, Leishmania mexicana CPB2.8DeltaCTE and sorted by a high-throughput instrument, COPAS beadsorter (up to 200 000 beads/h). Forty-eight hits were analyzed by MALDI-TOF MS providing structural information about the protease specificity, and 23 peptidotriazoles were resynthesized and evaluated in solution, with the best inhibitor displaying a K(i) value of 76 nM. A one-pot procedure was used to convert Fmoc-amino azides into their corresponding Boc derivatives. The crucial influence of weak interactions with a spacer used for detection by MALDI-TOF MS on screening results was observed. 相似文献
7.
We prove that three independent fuzzy systems can uniformly approximate Bayesian posterior probability density functions by approximating the prior and likelihood probability densities as well as the hyperprior probability densities that underly the priors. This triply fuzzy function approximation extends the recent theorem for uniformly approximating the posterior density by approximating just the prior and likelihood densities. This approximation allows users to state priors and hyper-priors in words or rules as well as to adapt them from sample data. A fuzzy system with just two rules can exactly represent common closed-form probability densities so long as they are bounded. The function approximators can also be neural networks or any other type of uniform function approximator. Iterative fuzzy Bayesian inference can lead to rule explosion. We prove that conjugacy in the if-part set functions for prior, hyperprior, and likelihood fuzzy approximators reduces rule explosion. We also prove that a type of semi-conjugacy of if-part set functions for those fuzzy approximators results in fewer parameters in the fuzzy posterior approximator. 相似文献
8.
本文的主要结果如下:(1)环R关于其乘法封闭子集S满足左Ore条件当且仅当R[σ1,σ2,…,σt]关于其相应乘法封闭子集S[σ1,σ2,…,σt]满足左Ore条件.(2)若R关于其乘法封闭子集S满足左Ore条件,S^-1 R是R关于S的左分式环,其自然同态为φ:R→S^-1R,则存在环同态φ:R[σ1,σ2,…,σt]→S[σ1,σ2,…,σt]^-1 R[σ1,σ2,…σt]使得(S-1R)[φ(σ1),φ-(σ2),…φ(σt)]≌S[σl,σ2,…,σt]^-1R[σ1,σ2,…σt]。 相似文献
9.
Dr. Sanya Pachisia Dr. Hina Goyal Aashish Dr. Gulshan Kumar Prof. Rajeev Gupta 《ChemCatChem》2024,16(2):e202301123
This work presents synthesis and characterization of two cobalt-based coordination polymers (CPs) prepared by using two positionally related pyridine-2,6-dicarboxamide fragment-based ligands containing appended arylcarboxylic acid groups. While arylcarboxylate groups of ligands coordinate to the Co(II) ions to produce 2D CPs; the amidic N−H groups remain free and generate large cavities lined with hydrogen bonds. Such hydrogen bonding cavities based CPs were found to reversibly adsorb molecular iodine. The Lewis acidic Co(II) ions and metal-coordinated labile solvent molecules in CPs promoted noteworthy heterogeneous catalysis for Friedel crafts reactions as well as multicomponent condensation reactions. 相似文献
10.
We present two ZnII‐ and CdII‐based coordination polymers (CPs), L ‐Zn and L ‐Cd , offering H‐bonding‐based cavities of varying dimensions. Both CPs were used for the highly selective detection of S2O72? and Fe3+ ions where H‐bonding based cavities played an important role. Fluorescence quenching, competitive binding studies and binding parameters substantiated significant recognition of S2O72? and Fe3+ ions by both CPs. 相似文献