Optimization and One-Step Purification of Recombinant V Antigen Production from Yersinia pestis

The purpose of this study was to develop an efficient and inexpensive method for the useful production of recombinant protein V antigen, an important virulence factor for Yersinia pestis. To this end, the synthetic gene encoding the V antigen was subcloned into the downstream of the intein (INT) and chitin-binding domain (CBD) from the pTXB1 vector using specific primers. In the following, the produced new plasmid, pTX-V, was transformed into E. coli ER2566 strain, and the expression accuracy was confirmed using electrophoresis and Western blotting. In addition, the effects of medium, inducer, and temperature on the enhancement of protein production were studied using the Taguchi method. Finally, the V antigen was purified by a chitin affinity column using INT and CBD tag. The expression was induced by 0.05 mM IPTG at 25 °C under optimal conditions including TB medium. It was observed that the expression of the V-INT�CBD fusion protein was successfully increased to more than 40 of the total protein. The purity of V antigen was as high as 90. This result indicates that V antigen can be produced at low cost and subjected to one-step purification using a self-cleaving INT tag. © 2020, Springer Science+Business Media, LLC, part of Springer Nature

Investigation about Structural and Optical Properties of Bulk and Thin Film of 1H-CaAlSi by Density Functional Method

Optical properties of bulk and thin film of 1H-CaAlSi for two directions (1,0,0) and (0,0,1) were studied. The calculations are carried out by Density Functional Theory (DFT) method using full potential. GGA approximation was used to calculate exchange-correlation energy. The calculations are performed by WIEN2k package. The results showed that the absorption edge is shifted backward 0.82eV in the thin film than the bulk for both directions. The static values of the real part of dielectric function for four cases were obtained. The static values of the refractive index for four cases are calculated too. The reflectivity graphs have shown an intensive difference between the reflectivity of the thin film and the bulk in the ultraviolet region

Observations of twinning in YBa2Cu3O6+x, 0 < x < 1, at high temperatures

We report here on the nature of the twinning associated with the tetragonal to orthorhombic I (T/OI) phase transition in YBCO, for temperatures between 500 and 600ºC. In situ neutron diffraction measurements show the coexistence of the T and split OI peaks in the vicinity of the transition. However, by direct numerical simulation, we show that this is to be expected from the twinned OI structure when the separation of adjacent twinning planes and the orthorhombicity both approach zero. It is demonstrated that the observed hkl-dependent peak broadening is consistent with this interpretation. A comparison of the measured and simulated peak shapes enables us to make an approximate estimate of the actual twin widths for a given orthorhombicity