One-step purification of lactoperoxidase from bovine milk by affinity chromatography

Sulphanilamide was determined to be a new inhibitor of lactoperoxidase (LPO) with an IC₅₀ of 0.848.10⁻⁵ M. The K_i for sulphanilamide was determined to be 3.57.10⁻⁵ M and sulphanilamide showed competitive inhibition, which makes it a suitable ligand for constructing a Sepharose 4B-l-tyrosine affinity matrix. The affinity matrix was synthesised by coupling sulphanilamide as the ligand and l-tyrosine as the spacer arm to a cyanogen bromide (CNBr)-activated-Sepharose 4B matrix. Lactoperoxidase was purified 409-fold from the synthesized affinity matrix in a single step, with a yield of 62.3% and a specific activity of 40.9 EU/mg protein. The enzyme activity was measured using ABTS as a chromogenic substrate (pH 6.0). The degree of LPO purification was monitored by SDS–PAGE and its R_z (A₄₁₂/A₂₈₀) value. The R_z value for the purified LPO was found to be 0.7. Maximum binding was achieved and K_m and V_max values were determined.     

Analysis‐preserving video microscopy compression via correlation and mathematical morphology

The large amount video data produced by multi‐channel, high‐resolution microscopy system drives the need for a new high‐performance domain‐specific video compression technique. We describe a novel compression method for video microscopy data. The method is based on Pearson's correlation and mathematical morphology. The method makes use of the point‐spread function (PSF) in the microscopy video acquisition phase. We compare our method to other lossless compression methods and to lossy JPEG, JPEG2000, and H.264 compression for various kinds of video microscopy data including fluorescence video and brightfield video. We find that for certain data sets, the new method compresses much better than lossless compression with no impact on analysis results. It achieved a best compressed size of 0.77% of the original size, 25× smaller than the best lossless technique (which yields 20% for the same video). The compressed size scales with the video's scientific data content. Further testing showed that existing lossy algorithms greatly impacted data analysis at similar compression sizes. Microsc. Res. Tech. 78:1055–1061, 2015. © 2015 Wiley Periodicals, Inc.     

N‐Benzyl‐4‐((heteroaryl)methyl)benzamides: A New Class of Direct NADH‐Dependent 2‐trans Enoyl–Acyl Carrier Protein Reductase (InhA) Inhibitors with Antitubercular Activity

Isoniazid (INH) remains one of the cornerstones of antitubercular chemotherapy for drug‐sensitive strains of M. tuberculosis bacteria. However, the increasing prevalence of multidrug‐resistant (MDR) and extensively drug‐resistant (XDR) strains containing mutations in the KatG enzyme, which is responsible for the activation of INH into its antitubercular form, have rendered this drug of little or no use in many cases of drug‐resistant tuberculosis. Presented herein is a novel family of antitubercular direct NADH‐dependent 2‐trans enoyl–acyl carrier protein reductase (InhA) inhibitors based on an N‐benzyl‐4‐((heteroaryl)methyl)benzamide template; unlike INH, these do not require prior activation by KatG. Given their direct InhA target engagement, these compounds should be able to circumvent KatG‐related resistance in the clinic. The lead molecules were shown to be potent inhibitors of InhA and showed activity against M. tuberculosis bacteria. This new family of inhibitors was found to be chemically tractable, as exemplified by the facile synthesis of analogues and the establishment of structure–activity relationships. Furthermore, a co‐crystal structure of the initial hit with the enzyme is disclosed, providing valuable information toward the design of new InhA inhibitors for the treatment of MDR/XDR tuberculosis.     

Morphology, ultrastructure, and implied function of ciliated sensory structures on the developmental stages of Merizocotyle icopae (Monogenea: Monocotylidae)

Experimental infections were used to track the fate of the dorsal sensilla of Merizocotyle icopae (Monogenea: Monocotylidae) from nasal tissue of the shovelnose ray, Rhinobatos typus (Rhinobatidae). Scanning and transmission electron microscopy revealed that 3 types of uniciliate dorsal sensilla exist at different times in the development of the monogenean. Type 1 sensilla have little or no invagination where the cilium exits the distal end of the dendrite and possess a ring of epidermis surrounding the cilium distal to the invagination. Type 2 sensilla have a deep invagination where the cilium exits the dendrite. Type 3 sensilla can be distinguished from the other types by the shape of the dendrite. The larvae have predominantly Type 1 dorsal sensilla, most of which are lost approximately 24 h after infection and a few Type 2 sensilla, which are retained. Additional Type 2 sensilla (termed Adult Type 2 sensilla), which are slightly different morphologically from the Type 2 sensilla of the larvae, form in later stages of development. Numerous Type 3 sensilla are unique to the dorsal surface of adults. Loss of all Type 1 sensilla upon attachment to the host, R. typus, suggests that these may be chemo- or mechanoreceptors responsible for host location by the swimming infective larvae. Type 2 sensilla appear to be important in the larvae, juveniles, and adults whereas the modality mediated by Type 3 is specific to adults.     

美国乳清蛋白在运动营养方面的作用

<正> 运动员追求的是在竞赛中表现突出或最大程度地发挥个人潜能,而营养选择会影响运动员的表现,膳食混合物也会提高运动员的表现,这一认识激发了人们对于运动营养补足剂的兴趣。研究报告表明,乳清蛋白可以给运动员提供许多独特的益处,能促进快速恢复、增强免疫、提高训练成绩。临床试验表明,在膳食中加入乳清蛋白可直接提高运动员的表现。     

Three-dimensional non-isothermal model development of high temperature PEM Fuel Cells

A three-dimensional non-isothermal mathematical model is developed in a triple mixed serpentine flow multichannel domain for a high temperature PEM Fuel Cell having a phosphoric acid doped PBI membrane as electrolyte and an active area of 25 cm² within Comsol Multiphysics. The inlet temperatures of cathode and anode reactants are taken as 438 K. Model predicts pressure, and temperature distribution along the channels and membrane current density distribution over the membrane electrodes. The model results are obtained at two different operation voltages, 0.45 V and 0.60 V. Resulting average current densities are respectively 0.313 A cm^?2 and 0.224 A cm^?2. The non-isothermal model results are compared to isothermal model results from a previous study and various other single channel non-isothermal model results available in the literature. The pressure drop at cathode compartment is predicted to be 6500 Pa, whereas it is found to be 6400 Pa for the isothermal model. The temperature difference within the system is found to be 0.18 K for the operation voltage of 0.6 V, whereas this value increases to 0.31 K for the operation voltage of 0.45 V. The temperature difference isocontours are illustrated for the whole cell. Considering changes in temperature, one can employ isothermal operation assumption for this system as an approximation and simplification for the governing equations, since the variation in the temperature within the cell is less than 1 K. It should be emphasized that multichannel model predictions are more realistic compared to single channel models. The model developed here can be extended to larger electrode active area and different multichannel configurations.     

Ultrathin polypyrrole films on self-assembled monolayers as an efficient ultramicroelectrode assay

In this work, we investigated the effect of electrodeposition of polypyrrole (PPy) films on two different self-assembled monolayers (SAMs) modified gold electrode for the electrochemical construction of ultramicroelectrode (UME). In order to obtain SAM modified surfaces, 4-mercapto-1-butanol and 11-mercaptoundecanoic acid were used. The effect of these two chains on pyrrole electropolymerization was compared. Electropolymerization of pyrrole on SAM modified Au electrode was carried out by using cyclic voltammetry (CV) and constant potential electrolysis. To investigate the UME formation, the obtained surfaces were tested in Fe(CN)₆^3−/4− redox system. UMEs were characterized using scanning electron microscopy energy-dispersive X-ray spectroscopy, attenuated total reflectance fourier transform infrared spectroscopy and electrochemical impedance spectroscopy. The designed UME was applied as an immobilization matrix to entrap a redox protein, Hemoglobin (Hb), as a model. Direct electron transfer between this protein and the fabricated thiol modified PPy based UME was achieved, which is very challenging on bare electrode surfaces. With this study, a simple, low-cost and reproducible UME production way has been successfully accomplished and Hb modified UME is promising for different bioanalytical applications, for instance; cellular hydrogen peroxide or nitrite sensing.     

A DNA-based demonstration of a three-host life-cycle for the Bivesiculidae (Platyhelminthes: Digenea)

Immature bivesiculid trematodes collected from the intestine of Thlalassoma lunare (Labridae) are shown to be morphologically consistent with adults of Bivesicula claviformis from Epinephelus fasciatus (Serranidae). In addition, the immature bivesiculids have the same sequence for the second internal transcribed spacer of the ribosomal DNA. Comparison with three other species of Bivesiculidae showed differences of between 23% and 30%. These results show that bivesiculids may have three-host life-cycles in addition to the two-host life-cycles that have been demonstrated previously. The three-host life-cycle enables bivesiculids to infect large carnivorous fishes.