An eukaryotic expression system of Congjiang pigs IFN-λ1 was constructed to obtain its expression in CHO-K1 cells and the inhibition effect of Congjiang pig IFN-λ1 on PRRSV proliferation was verified. The eukaryotic expression plasmid pEGFP-PoIFN-λ1 was constructed from the pig IFN-λ1 gene fragment and transfected into CHO-K1 cells. Expression was detected by fluorescence microscopy and Western blotting. The influence on the proliferation of PRRSV was assessed. The results of the study showed that the recombinant plasmid pEGFP-PoIFN-λ1 was constructed correctly. After transfection, green fluorescent signal was detected in CHO-K1 cells by fluorescence microscopy. Western blot analysis revealed that in cells at different time periods after transfection, porcine IFN-λ1 was expressed, with the highest expression observed 36 h after transfection. The antiviral activity of the supernatant after 36 h of transfection was determined by the micro cytopathic inhibition method, and the biological activity was 2.1×103 U/mL. Quantitative PCR was used to detect the proliferation of PRRSV, and the results showed that Congjiang pigs IFN-λ1 significantly inhibited the mRNA expression of PRRSV and viral proliferation in a dose- and time-dependent manner. This study established a Congjiang pig IFN-λ1 eukaryotic expression system, and the quantitative PCR method showed that it has a significant inhibitory effect on the proliferation of PRRSV, which lays a foundation for the future production of antiviral drugs and clinical application.

Steel is basically used in construction, automobile, buildings, infrastructure, tools, ships, appliances, machines and weapons due to its good mechanical as well as metallurgical properties. Heat treatment of steels significantly enhance its mechanical and metallurgical properties due to the formation of various phases depending upon the type of steel used for specific application. In present study, blank of EN353 grade steel having different sizes were used to investigate the effect of heat treatment and microstructural changes. JMat-Pro software was used to predict the continuous cooling transformation behaviour of EN353 steel. Different phases such as bainite, perlite and other carbide inclusion can be observed in the microstructural examination. Pearlitic microstructure developed for the specimen of size 40×40×40 mm heated at 870°C for 2 hrs and then isothermal heating was performed for same specimen at 600°C for 73 min followed by air cooling.
Relevance Statement: Steel is an important material which is frequently used in almost all areas such as structure building, pressure vessels, transportation and many more other applications. Addition of alloying elements in parent steel significantly improve the metallurgical as well as mechanical properties. Steel properties like tensile strength, toughness, ductility, corrosion resistance, wear resistance, hardness, hot hardness, weldability, fatigue etc. significantly improved with the addition of alloying and heat treatment. Heat treatment processes can be used to improve the properties of steel which are frequently used in many manufacturing industries. Different grades of steels which are heat treated under a set of sequence of heating and cooling to change their physical and mechanical properties so that it can fulfil its function under loading condition. With the help of heat treatment process desired microstructure has been achieved which exhibit good mechanical properties of steels.