Improving the Behavioral Intention of Continuous Online Learning Among Learners in Higher Education During COVID-19.

The COVID-19 pandemic caused colleges and universities to rely heavily on online learning to continue knowledge dissemination to learners. This study used the second-generation model of unified theory of acceptance and use of technology (UTAUT2) to comprehensively analyze the mediating effects of self-efficacy, which affects learners' effective use of online tools for learning, and capability of metacognition and self-regulation, which can independently adjust learning progress into the UTAUT2 model, on the learner's willingness to continue online learning [i.e., their behavioral intention (BI)] by constructing a UTAUT2-based e-learning model. This study administered questionnaires to undergraduates in universities in East China to collect data. The effects of performance expectancy, effort expectancy (EE), social influence (SI), and facilitating conditions (FCs), hedonic motivation (HM), price value (PV), and habits on BI (directly or through mediators) were analyzed through data analysis and structural equation modeling, and the UTAUT2-based e-learning model was accordingly modified. The results indicated that the self-efficacy enhanced the effects of EE, SI, FCs, HM, and PV on learners' BI; that metacognition and self-regulation (MS) capabilities enhanced the effects of EE on learners' BI; and that habits had a direct and strong effect on BI. This study also provided some suggestions to enhance higher education learners' willingness to continue online learning, such as improving social recognition and support, careful design of teaching content, easy-to-use technology, financial support. These results and suggestions may guide colleges and universities in conducting, continuing, or enhancing online education, particularly as the pandemic continues.

Identification and expression analysis of caffeoyl-coenzyme A O-methyltransferase family genes related to lignin biosynthesis in tea plant (Camellia sinensis).

Tea plant, an economically important crop, is used in producing tea, which is a non-alcoholic beverage. Lignin, the second most abundant component of the cell wall, reduces the tenderness of tea leaves and affects tea quality. Caffeoyl-coenzyme A O-methyltransferase (CCoAOMT) involved in lignin biosynthesis affects the efficiency of lignin synthesis and lignin composition. A total of 10 CsCCoAOMTs were identified based on tea plant genome. Systematic analysis of CCoAOMTs was conducted for its physicochemical properties, phylogenetic relationships, conserved motifs, gene structure, and promoter cis-element prediction. Phylogenetic analysis suggested that all the CsCCoAOMT proteins can be categorized into three clades. The promoters of six CsCCoAOMT genes possessed lignin-specific cis-elements, indicating they are possibly essential for lignin biosynthesis. According to the distinct tempo-spatial expression profiles, five genes were substantially expressed in eight tested tissues. Most CsCCoAOMT genes were expressed in stems and leaves in three tea plant cultivars 'Longjing 43,' 'Anjibaicha,' and 'Fudingdabai' by RT-qPCR detection and analysis. The expression levels of two genes (CsCCoAOMT5 and CsCCoAOMT6) were higher than those of the other genes. The expression levels of most CsCCoAOMT genes in 'Longjing 43' were significantly higher than that those in 'Anjibaicha' and 'Fudingdabai.' Correlation analysis revealed that only the expression levels of CsCCoAOMT6 were positively correlated with lignin content in the leaves and stems. These results lay a foundation for the future exploration of the roles of CsCCoAOMTs in lignin biosynthesis in tea plant.

Effects of shading on lignin biosynthesis in the leaf of tea plant (Camellia sinensis (L.) O. Kuntze).

Shading can effectively reduce photoinhibition and improve the quality of tea. Lignin is one of the most important secondary metabolites that play vital functions in plant growth and development. However, little is known about the relationship between shading and xylogenesis in tea plant. To investigate the effects of shading on lignin accumulation in tea plants, 'Longjing 43' was treated with no shading (S0), 40% (S1) and 80% (S2) shading treatments, respectively. The leaf area and lignin content of tea plant leaves decreased under shading treatments (especially S2). The anatomical characteristics showed that lignin is mainly distributed in the xylem of tea leaves. Promoter analysis indicated that the genes involved in lignin pathway contain several light recognition elements. The transcript abundances of 12 lignin-associated genes were altered under shading treatments. Correlation analysis indicated that most genes showed strong positive correlation with lignin content, and CsPAL, Cs4CL, CsF5H, and CsLAC exhibited significant positively correlation under 40% and 80% shading treatments. The results showed that shading may have an important effect on lignin accumulation in tea leaves. This work will potentially helpful to understand the regulation mechanism of lignin pathway under shading treatment, and provide reference for reducing lignin content and improving tea quality through shading treatment in field operation.

Identification and Analysis of Genes Involved in Auxin, Abscisic Acid, Gibberellin, and Brassinosteroid Metabolisms Under Drought Stress in Tender Shoots of Tea Plants.

Endogenous phytohormones auxin (indole-3-acetic acid [IAA]), abscisic acid (ABA), gibberellin (GA3), and brassinosteroid (BR) play a role in responses to drought stress in higher plants. Tea plant is one of the major economic corps worldwide. The tender shoots of tea plants are the main source for tea production. The effects of drought stress on endogenous IAA, ABA, GA3, and BR metabolisms in tender shoots of tea plants need to be illustrated. In this study, a total of 17 IAA-related genes, 17 ABA-related genes, 18 GA3-related genes, and 8 BR-related genes were identified under drought stress in tender shoots of tea plants, respectively. By using a combination of phytohormone determination, phylogenetic tree construction and sequence analysis, gene expression profiles, functional classification, Kyoto encyclopedia of genes and genomes enrichment, and distribution of genes analysis, we have demonstrated that IAA, ABA, GA3, and BR metabolisms might participate in the regulation of the response to drought stress in tender shoots of tea plants. The expression level of CsLYCE negatively correlated with ABA accumulation under drought stress. Our findings could shed new light on the effects of drought stress on the IAA, ABA, GA3, and BR metabolisms in tender shoots of tea plants.

[Effects of Marsdenia tenacissima extract on proliferation and apoptosis of hematologic neoplasm cell line cells].

OBJECTIVE: To investigate the effects of the extract from Marsdensia tenacissima on proliferation and apoptosis of human hematologic neoplasm cell line cells. METHODS: Raji, NB4 and K562 cells were treated in vitro with different concentrations of the extract from Marsdensia tenacissima, including different ethanol elution components and C21 steroidal saponin monomer compounds, for different periods. Tumor cell proliferation was measured by MTT colorimetric assay and its apoptosis was determined by the flow cytometry (FCM). RESULTS: Firstly, with higher concentrations, 100 microg/mL and 200 microg/mL, 70% ethanol eluate from Marsdensia tenacissima inhibited the proliferation of Raji, NB4 and K562 cells significantly, in a dose and time dependent manner, compared with 30% and 50% ethanol elution components from Marsdensia tenacissima (P < 0.05). Secondly, four C21 steroidal saponin monomer compounds, tenacissosides B,C,I and marsdenoside K, also inhibited the proliferation of Raji, NB4 and K562 cells in vitro significantly, in a dose and time dependent manner, compared with that of control group (P < 0.05). Among them, tenacissoside C showed the strongest inhibition effects on proliferation of these cells under all experimental conditions compared with the other three C21 steroidal saponin monomer compounds (P < 0.05). Furthermor, the IC50 of tenacissosides C on proliferation of Raji, NB4 and K562 cells were 64.1 micromol/L, 70.4 micromol/L and 105.8 micromol/L, respectively. Finally, after Raji, NB4 and K562 cells were treated with 98.4 micromol/L tenacissoside C for 24 h and 48 h, the early apoptosis rates and late apoptosis rates of these tumor cells increased markedly, compared with the control group (P < 0.05). CONCLUSION: The extract from Marsdensia tenacissima, including different ethanol elution components and C21 steroidal saponin monomer compounds, may inhibit the proliferation of some human hematologic neoplasm cell line cells and induce these tumor cells apoptosis in vitro, especially tenacissoside C, one of the C21 steroidal saponin monomer compounds, showed the strongest effects on proliferation of these tumor cells when compared with other ones, with the strongest inhibition activities on human Burkitt's lymphoma cell line Raji cells.

[Antitumor effects of matrix protein of vesicular stomatic virus on EL4 lymphoma mice].

OBJECTIVE: To explore antitumor effects of plasmid pcDNA3. 1-MP encoding matrix protein of vesicular stomatitis virus (VSV) complexed with cationic liposome (DOTAP:CHOL) in mice with EL4 lymphoma. METHODS: C57BL/6 mouse model with EL4 lymphoma was established. Sixty mice bearing EL4 lymphoma were divided randomly into five groups including Lip-MP, Lip-pVAX, Lip, ADM and NS groups, which were intravenously injected with liposome-pcDNA 3. 1-MP complex, liposome-pVAX complex, empty liposome, Adriamycin and normal saline respectively every three days. Tumor volumes and survival time were monitored. Microvessel density and tumor proliferative index in tumor tissues were determined by CD31, Ki-67 immunohistochemistry staining, meanwhile the tumor apoptosis index was measured by TUNEL method. RESULTS: From 6 days after treatments on, the tumor volume in Lip-MP group was much smaller than that in Lip-pVAX, Lip and NS group (P < 0.05). The median survival time of mice in Lip-MP group, 44 days after inoculation of tumor cells, was significantly higher than that in other groups (P < 0.05), which was 39 days, 38.5 days and 34 days in Lip-pVAX, Lip and NS groups respectively. The MVD value in tumor tissues in Lip-MP group was less than that in Lip-pVAX, Lip and NS groups (P < 0.05). Ki67 staining revealed that Lip-MP complex apparently suppressed the proliferation of EL4 tumor cells in vivo (P < 0.05). TUNEL assays showed that apoptosis index of tumor cells in Lip-MP group, 10.60 +/- 1.71, was much higher than that in other three groups (P < 0.05). CONCLUSIONS: Lip-MP complex, the plasmid encoding matrix protein of VSV (VSV-MP) encapsulated in cationic liposome, significantly inhibited the growth of tumor and prolonged the survival of mice bearing EL4 lymphoma, which may be related to the induction of tumor cell apoptosis, inhibition of tumor angiogenesis, and suppression of tumor cell proliferation.

[Gene cloning of mIFN-gamma and construction of recombinant adenovirus].

OBJECTIVE: To develop a rapid and efficient method for preparing recombinant adenovirus containing mouse IFN-gamma (mIFN-gamma) gene by homologous recombination in E. coli. in order to build a foundation for research into gene therapy of liver fibrosis. METHODS: The target gene mIFN-gamma was amplified by using PCR from the vector pORF5-mIFN-gamma. Once verified, it was cut out by double endonucleases, then connected to the shuttle vector pAdTrack-CMV. The newly constructed vector was linearized by Pme I following transformation to the E. coli. BJ5183, which contained the backbone vector pAdEasy-1. The correct recombinant pAd-mIFN-gamma was selected by endonucleases and by Kanamycin resistance. Again it was linearized with Pac I , then transfected to AD-293 cells by means of Calcium Phosphate method. Finally, the target gene IFN-gamma was identified by PCR and Western blot methods. RESULTS: The target gene mIFN-gamma amplified by PCR was identified by DNA sequencing, which proved that the mIFN-gamma gene consisted of 468 nucleotides and was completely the same with the sequence published on the GenBank. The adenoviral vector constructed by homologous recombination had the gene of interest and the viral could be examined 4-6 days after transfection, and the green fluorescence intensity became greater at about 8-11 days. The adenovirus obtained at the 12th day was digested by protease K and then was amplified by PCR and identified by Western blot. The two methods proved that the adenovirus encoded the target gene mIFN-gamma. CONCLUSION: Preparing recombinant adenovirus containing mIFN-gamma gene by homologous recombination in E. coli. Is a rapid and efficient method. The Ad-mIFN-gamma can be propagated in 293 cell line. It may be used as a novel agent for gene therapy in liver fibrosis.