Porcine transmissible gastroenteritis virus (TGEV) and porcine epidemic diarrhea virus (PEDV) are the causative agents of highly fatal acute diarrhea in pigs, resulting in enormous losses in the pig industry worldwide. To develop an effective bivalent oral vaccine against TGEV and PEDV infection, the D antigenic site of the TGEV spike (S) protein and the major antigen site (core neutralizing epitope—COE) of the PEDV S protein were used as immunogens, and the enhanced green fluorescent protein (eGFP) gene was used as a reporter to construct genetically engineered Lactobacillus casei rLpPGF-T7g10-eGFP-6D-COE. The expression of proteins of interest by the recombinant L. casei was confirmed by confocal laser scanning microscopy and a Western blot assay, and the immunogenicity of rLpPGF-T7g10-eGFP-6D-COE in orally immunized mice was evaluated. The results showed that levels of anti-PEDV and anti-TGEV serum immunoglobulin G (IgG) and mucosal secreted immunoglobulin A (sIgA) antibodies obtained from the mice immunized with rLpPGF-T7g10-eGFP-6D-COE, as well as the proliferation levels of lymphocytes, were significantly higher than those in mice orally administered phosphate-buffered saline (PBS) or rLpPG-T7g10. Moreover, the serum IgG antibodies showed neutralizing effects against PEDV and TGEV. Our data suggest that the antibiotic resistance-free genetically engineered L. casei bivalent oral vaccine provides a safe and promising strategy for vaccine development against PEDV and TGEV.

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A high percentage of high-ash fine slime materials can deteriorate flotation selectivity through surface covering. This covering of the surface is one of the issues that need to be addressed for efficient flotation processing of difficult-to-separate and high-ash coals. In this study, we investigated the depression effect of SPP on high-ash fine mud by flotation kinetic tests. We also revealed the mechanism of SPP depression of fine slime flotation and enhanced flotation selectivity of difficult-to-separate and high-ash coals by means of Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), and Atomic Force Microscopy (AFM) analyses. The results showed that under the best condition of SPP dosage, clean coal with 9.75% ash content and 76.76% yield was obtained. Compared to the blank group, the ash content of the clean coal decreased by 2.39%, while the yield was only reduced by 2.18% in the presence of SPP. The reason for this was that the addition of SPP enhanced the stripping and dispersion of the gangue from the coal particle surface. The result was a reduction in the cover of the coal grain surface and an increase in the hydrophobic sites on the coal surface, thereby depressing the non-selective flotation of the gangue and enhancing the adsorption of the collector on the coal surface. The ash content of the flotation concentrate decreased, but the yield remained almost unchanged, which was the main reason for the better performance of SPP as a depressant compared to conventional depressants.