Due to the spread of COVID-19 worldwide, a large number of universities had to close their campuses. To maintain teaching and learning during this disruption to the traditional teaching, most universities have adopted online teaching model. The current study aimed at investigating the efficacy of various online teaching modes as well as comparing a proposed combined model of online and flipped learning to other online and traditional models. The Learning under COVID-19questionnaire was designed and administered to undergraduate engineering students at Chengdu University of Information Technology (CUIT). The questionnaire included five parts: demographic questions, frequencies of online courses, types of online courses, the communication and Q&A in online classes and the effect of online classes, as well as the effect of combined model learning. The results of the study showed that, students were dissatisfied with online learning in general, and they were especially dissatisfied with the communication and Q&A modes. In addition, the combined model of online teaching with the flipped learning improved students' learning, attention, and evaluation of courses.

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Porcine reproductive and respiratory syndrome virus (PRRSV) 1 and 2 differ in their recognition of CD163. Substitution of porcine CD163 SRCR5 domain with a human CD163-like SRCR8 confers resistance to PRRSV 1 but not PRRSV 2. The deletion of CD163 SRCR5 has been shown to confer resistance to PRRSV 1 in vivo and both PRRSV 1 and 2 in vitro . However, the anti-PRRSV 2 activity of modifying the CD163 SRCR5 domain has not yet been reported. Here, we describe the highly efficient generation of two pig breeds (Liang Guang Small Spotted and Large White pigs) lacking a short region of CD163 SRCR5, including the ligand-binding pocket. We generated a large number of gene-edited Large White pigs of the F0 generation for use in viral challenge studies. The results of this study show that these pigs are completely resistant to infection by species 2 PRRSV, JXA1, and MY strains. There were no clinical symptoms, pathological abnormalities, viremia, or anti-PRRSV antibodies in the CD163 SRCR5-edited pigs compared to wild-type controls after viral challenge. Porcine alveolar macrophages (PAMs) isolated from CD163 SRCR5-edited Large White pigs also displayed resistance to PRRSV in vitro . In addition, CD163 SRCR5-edited PAMs still exhibited a cytokine response to PRRSV infection, and no significant difference was observed in cytokine expression compared to wild-type PAMs. Taken together, these data suggest that CD163 SRCR5-edited pigs are resistant to PRRSV 2, providing a basis for the establishment of PRRSV-resistant pig lines for commercial application and further investigation of the essential region of SRCR5 involved in virus infection.

Polycystic ovary syndrome (PCOS) can cause reproductive disorders that may affect oocyte quality from punctured follicles in human follicular fluid (HFF). The non-coding RNA family includes micro RNA (miRNA), piwi-interacting RNA (piRNA) and transfer RNA (tRNA); these non-coding RNA transcripts play diverse functions and are implicated in a variety of diseases and health conditions, including infertility. In this study, to explore the role of HFF exosomes in PCOS, we extracted and sequenced RNA from HFF exosomes of PCOS patients and compared the analysis results with those of non-PCOS control group. The HFF exosomes were successfully isolated and characterized in a variety of ways. The sequencing results of the HFF exosomal RNA showed that about 6.6% of valid reads in the PCOS group and 8.6% in the non-PCOS group were successfully mapped to the human RNA database. Using a hierarchical clustering method, we found there were ten small RNA sequences whose expression was significantly different between the PCOS and non-PCOS groups. We chose six of them to predict target genes of interest for further GO analysis, and pathway analysis showed that the target genes are mainly involved in biosynthesis of amino acids, glycine, serine and glycosaminoglycan, as well as threonine metabolism. Therefore, the small RNA sequences contained in HFF EXs may play a key role in the mechanism that drives PCOS pathogenesis, and thereby can act as molecular biomarkers for PCOS diagnosis in the future.

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Bone morphogenetic protein 15 (BMP15) is strongly associated with animal reproduction and woman reproductive disease. As a multifunctional oocyte-specific secret factor, BMP15 controls female fertility and follicular development in both species-specific and dosage-sensitive manners. Previous studies found that BMP15 played a critical role in follicular development and ovulation rate in mono-ovulatory mammalian species, especially in sheep and human, but study on knockout mouse model implied that BMP15 possibly has minimal impact on female fertility of poly-ovulatory species. However, this needs to be validated in other poly-ovulatory species. To investigate the regulatory role of BMP15 on porcine female fertility, we generated a BMP15-knockdown pig model through somatic nuclear transfer technology. The BMP15-knockdown gilts showed markedly reduced fertility accompanied by phenotype of dysplastic ovaries containing significantly declined number of follicles, increased number of abnormal follicles, and abnormally enlarged antral follicles resulting in disordered ovulation, which is remarkably different from the unchanged fertility observed in BMP15 knockout mice. Molecular and transcriptome analysis revealed that the knockdown of BMP15 significantly affected both granulosa cells (GCs) and oocytes development, including suppression of cell proliferation, differentiation, and follicle stimulating hormone receptor (Fshr) expression, leading to premature luteinization and reduced estradiol (E2) production in GCs, and simultaneously decreased quality and meiotic maturation of oocyte. Our results provide in vivo evidence of the essential role of BMP15 in porcine ovarian and follicular development, and new insight into the complicated regulatory function of BMP15 in female fertility of poly-ovulatory species.