Exploring Effects of Protease Choice and Protease Combinations in Enzymatic Protein Hydrolysis of Poultry By-Products

A study of the effects of single and combined protease hydrolysis on myofibrillar versus collagenous proteins of poultry by-products has been conducted. The aim was to contribute with knowledge for increased value creation of all constituents of these complex by-products. A rational approach was implemented for selecting proteases exhibiting the most different activity towards the major protein-rich constituents of mechanically deboned chicken residue (MDCR). An initial activity screening of 18 proteases on chicken meat, turkey tendons and MDCR was conducted. Based on weight yield, size exclusion chromatography (SEC) and SDS-PAGE, stem Bromelain and Endocut-02 were selected. Studies on hydrolysis of four different poultry by-products at 40 °C, evaluated by protein yield, SEC, and SDS-PAGE, indicate that the proteases’ selectivity difference can be utilized in tailor-making hydrolysates, enriched in either meat- and collagen-derived peptides or gelatin. Three modes of stem Bromelain and Endocut-02 combinations during hydrolysis of MDCR were performed and compared with single protease hydrolysis. All modes of the protease combinations resulted in a similar approximately 15% increase in product yield, with products exhibiting similar SEC and SDS-PAGE profiles. This shows that irrespective of the modes of combination, the use of more than one enzyme in hydrolysis of collagen-rich material can provide means to increase the total protein yield and ultimately contribute to increased value creation of poultry by-products.     

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Transition probabilities in Sm II via optical nutation

We have measured the transition probabilities for three lines in Sm II. The measurements are made by studying optical nutation with a fast Doppler switching technique in collinear laser spectroscopy on ion beams. The recorded nutation curves are fitted to a quantum-optical theoretical model, and the transition probabilities are extracted. For all three lines, the measured transition probabilities are more accurate than those of earlier published measurements.     

Aligned cellulose nanocrystals and directed nanoscale deposition of colloidal spheres

Cellulose nanocrystals are aligned in wrinkled polydimethylsiloxane templates and transferred to polyethyleneimine-coated silica surfaces in a printing process similar to microcontact printing. The highly aligned nanorods were deposited onto the surfaces with a line-to-line distance of 225–600 nm without loss of alignment. It was also possible to repeat the transfer process on the same surface at a 90-degree angle to create a network structure. This demonstrates the versatility of the technique and creates more options for advanced multilayering of materials. To demonstrate that the surface properties of the anionic cellulose nanorods were unaffected by the transfer process and to prove the concept of functionalizing transferred particles, cationic latex particles were electrostatically self-assembled onto the cellulose nanorods. The directed deposition of these particles resulted in excellent site specificity and the highest resolution to date for controlled deposition of colloids on an electrostatically patterned surface.     

Separation of neoglycoproteins with different degrees of glycosylation by boronate chromatography

Summary The separation of glycoproteins as glycoforms with specific degrees of glycosylation has been a problem until now. A technique involving boronate affinity chromatography has been developed to separate a heterogeneous sample of neoglycoprotein, chymotrypsin modified with maltose via reductive amination, into individual fractions with different degrees of glycosylation. Low-molecular-mass polyhydroxyl compounds, such as tris(hydroxymethyl)aminomethane (Tris), pentaerythritol, and triethanolamine proved efficient eluents due to their ability to form strong tridentate complexes with the boronate ligand. Compounds leading to either; too strong interaction with the boronate ligand (e. g. D-sorbitol and polyvinly alcohol), or too weak or no interaction (e. g. dextran) were not suitable eluents. The study provided the opportunity to probe further into the effect of glycosylation on the function of glycoproteins.     

Explicit Elastic Curves

The equilibria of thin rods are given by curves which are critical points of the modified total squared curvature. The critical curves are known as elastic curves. It is shown how all the elastic curves are given explicitly in terms of elliptic functions as soon as a certain set of three parameters is known. Every regular curve can be parametrized to have a constant speed but the parametrization is rarely known explicitly. Remarkably, all the elastic curves are here explicitly parametrized to have a constant speed. Curves with fixed distinct endpoints as well as closed curves are admitted. The tangent direction may be constrained at one, both, or neither of the endpoints. There are three major strands of formulas corresponding to: fixed length L, variable length without tension, and variable length with tension (let > 0 and add a term L to the total squared curvature). In the most complicated cases the three parameters are given as solutions to a non-linear system of three equations. In the least complicated case everything is given explicitly in terms of elliptic functions. If the length is variable and there is no tension, at least one of the parameters is completely determined (the elliptic modulus m = 1/2). Using the same set of parameters explicit formulas are given for: the length when it is variable, the total squared curvature, and the tangent angle along the elastic curve. A number of examples are presented which illustrate the full range of constraints.     

8-Bromo-6-alkylamino-2-trifluoromethyl-9H-purines with in vitro activity against influenza a virus

Several derivatives of 8-bromo-6-dimethylamino-2-trifluoromethyl-9H-purine ( 1 ) were synthesized for structure-activity relationship studies of anti-influenza A virus activity. The 8-bromopurines were prepared by reaction of the anion of the 6-alkylamino-2-trifluoromethylpurines with N-bromosuccinimide. Several compounds had anti-influenza activity comparable to ribavirin, but no in vivo activity was observed.     

三价铬丙二酸配合物[Cr(C3H2O4)(H2O)4][Cr(C3H2O4)2(H2O)2]·4H2O的合成、晶体结构及性质研究

在三重桥氧三核铬羧酸配合物的系列研究中,采用与铬的一元羧酸配合物类似的实验条件,以丙二酸为配体合成了不同构型的配合物[Cr(C₃H₂O₄)(H₂O)₄)][Cr(C₃H₂O₄)₂(H₂O)₂]·4H₂O,通过X射线衍射测定了其单晶结构,并对-COO的配位方式作了讨论,还研究了配合物的红外光谱、拉曼光谱、紫外可见光谱、质谱、磁化率等性质,探讨了性质与结构的关系,并由此论证了二元羧酸和铬形成的双齿螯合构型化合物的稳定性.     

Aggregation and interfacial properties of an isomerically pure alkylaryl sulfonate

Sodium dodecylorthoxylene sulfonate (SDOXS) was studied as an isomerically pure compound in micellar and microemulsion solutions. The particular isomer of SDOXS used in this work is one in which the sulfonate group is located ortho to the alkyl chain on the xylene ring. Aggregation of SDOXS in deuterated water was followed by specific conductivity and ²³Na NMR measurements at several temperatures. The aggregate size distribution at low concentrations agrees with the picture expected for ideal cooperative micellization but the data show deviations from this behavior at higher concentrations. This suggests either an increase in the average aggregation number with increasing concentration or an enhanced counterion binding at higher concentrations. ¹³C NMR spectra indicate that the benzene-ring motion slows down and the head-group solvation changes at high SDOXS concentrations or with the addition of electrolyte. A similar result was found for a microemulsion solution of SDOXS, n-octane, and NaCl brine. We discuss our results in view of the positional substitution pattern of the SDOXS aromatic ring.     

Collision-induced time shift of a dispersion-managed soliton and its minimization in wavelength-division-multiplexed transmission

The formula for the time shift of a dispersion-managed soliton that results from its collision with other solitons in different channels consists of two terms, one related to the frequency shift during collision, and the other related to the residual frequency shift after collision. It is found that an optimal relative delay exists between pulses in adjacent channels after each dispersion-managed span that balances the contributions from the two terms and minimizes the overall time shift, leading to a substantial improvement in transmission performance.