The nucleolus is a dynamic subnuclear structure, which is crucial to the normal operation of the eukaryotic cell. The porcine epidemic diarrhea virus (PEDV), coronavirus nucleocapsid (N) protein, plays important roles in the process of virus replication and cellular infection. Virus infection and transfection showed that N protein was predominately localized in the cytoplasm, but also found in the nucleolus in Vero E6 cells. Furthermore, by utilizing fusion proteins with green fluorescent protein (GFP), deletion mutations or site-directed mutagenesis of PEDV N protein, coupled with live cell imaging and confocal microscopy, it was revealed that, a region spanning amino acids (aa), 71–90 in region 1 of the N protein was sufficient for nucleolar localization and R87 and R89 were critical for its function. We also identified two nuclear export signals (NES, aa221–236, and 325–364), however, only the nuclear export signal (aa325–364) was found to be functional in the context of the full-length N protein. Finally, the activity of this nuclear export signal (NES) was inhibited by the antibiotic Lepomycin B, suggesting that N is exported by a chromosome region maintenance 1-related export pathway.

Transportation is the main way to solve the regional separation of supply and demand of China's coal resources. Aiming at the problem of coal transportation path selection, this paper constructs a comprehensive coal transportation path selection model, and selects ant colony algorithm as the main algorithm tool to solve the problem based on the actual coal transportation network in China. The model finds the optimal path and minimizes the transportation cost of the whole network under the condition that the supply of node is limited and the demand of each consumer place is satisfied. Therefore, it is of great practical and theoretical significance to improve the division and layout of the coal transportation market, make full use of the existing transportation conditions and reduce the logistics cost by studying the multimodal transport route selection of China's coal resources.