Background The emerging of psychological problems triggered by COVID-19 particularly in children have been extensively highlighted and emphasized, but original research in this respect is still lagging behind. Therefore, we designed this study to evaluate the impact of COVID-19 pandemic on mental health and the effectiveness and attitudes towards online education among Chinese children aged 7–15 years. Methods A detailed questionnaire, comprising of 62 questions was designed and parents or caretakers of 7 to 15 years old children were invited to participate via WeChat, a multi-purpose messaging, social media and mobile payment app, which is widely used by the Chinese population. A total of 668 parents across different regions of China were included. Results During COVID-19 pandemic, 20.7 and 7.2% children report experiencing post-traumatic stress disorder (PTSD) and depressive symptoms due to the COVID-19 pandemic. PTSD and SMFQ-P scores are significantly higher in middle school and boarding school students compared to primary and day school students. Multiple logistic regression analysis revealed that school system and province of origin are factors significantly associated with developing PSTD symptoms. 44.3% respondents feel online education is effective in gaining knowledge and improving practical and communications skills. 78.0% believe the online education system is efficient. Overall 79.8% respondents are satisfied and children can adapt to this new education system. During the COVID-19 pandemic, we found 1 in five children have PTSD and 1 in 14 children have depressive symptoms. Conclusion In summary, COVID-19 epidemic has caused PTSD and depression symptoms among Chinese children aged 7 to 15 years. In general, a large proportion of respondents are satisfied with online education, but still a substantial proportion of students are not comfortable with this new form of learning. Authorities should optimize online education systems and implement effective interventions to cope with the psychological effects of COVID-19 on children, as it is affecting the global population and remains uncertain when it will end.

Silk glands are specialized in the synthesis of several secretory proteins. Expression of genes encoding the silk proteins in Bombyx mori silk glands with strict territorial and developmental specificities is regulated by many transcription factors. In this study, we have characterized B. mori sage, which is closely related to sage in the fruitfly Drosophila melanogaster. It is termed Bmsage; it encodes transcription factor Bmsage, which belongs to the Mesp subfamily, containing a basic helix–loop–helix motif. Bmsage transcripts were detected specifically in the silk glands of B. mori larvae through RT-PCR analysis. Immunoblotting analysis confirmed the Bmsage protein existed exclusively in B. mori middle and posterior silk gland cells. Bmsage has a low level of expression in the 4th instar molting stages, which increases gradually in the 5th instar feeding stages and then declines from the wandering to the pupation stages. Quantitative PCR analysis suggested the expression level of Bmsage in a high silk strain was higher compared to a lower silk strain on day 3 of the larval 5th instar. Furthermore, far western blotting and co-immunoprecipitation assays showed the Bmsage protein interacted with the fork head transcription factor silk gland factor 1 (SGF1). An electrophoretic mobility shift assay showed the complex of Bmsage and SGF1 proteins bound to the A and B elements in the promoter of fibroin H-chain gene(fib-H), respectively. Luciferase reporter gene assays confirmed the complex of Bmsage and SGF1 proteins increased the expression of fib-H. Together, these results suggest Bmsage is involved in the regulation of the expression of fib-H by being together with SGF1 in B. mori PSG cells.

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Saline-alkali stress seriously restricts rice growth, development, and production in northern China. The damage of alkaline stress on rice is much greater than that of salt due to ion toxicity, osmotic stress, and especially high pH. As a signal molecule, melatonin (N-acetyl-5-methoxytryptamine, MT) mediates many physiological processes in rice and participates in protecting rice from abiotic stress. The potential mechanism of exogenous melatonin-mediated alkaline stress tolerance is still largely unknown. In this study, the effects of melatonin on the morphological change, physiological property, and corresponding genes expression in rice seedlings were analyzed under alkaline stress (20 mmol L−1, pH 9.55). The results showed that the expression levels of MT synthesis genes (TDC2, T5H, SNAT, ASMT1, and ASMT2) were induced by both exogenous MT and alkaline stress treatment. The cell membrane was protected by MT, and the MT furtherly play role in scavenging reactive oxygen species (ROS), reducing lipoxygenase (LOX) activity, and malondialdehyde (MDA) content. The scavenging of ROS by melatonin is attributed to the coupling of the improvement of redox homeostasis and the enhancement of antioxidant enzyme activity and antioxidant content by upregulating the transcriptional levels of antioxidase genes. In the meantime, MT pretreatment promoted the accumulation of free proline, sucrose, and fructose by regulating the OsP5CS, OsSUS7, and OsSPS1 gene expression level and increased chlorophyll content upregulating the expression of chlorophyll synthesis-related genes. Ultimately, the alleviating effect of exogenous melatonin on alkaline stress was reflected in increasing the leaf relative water content (RWC) and root-shoot ratio and reducing the leaf tip wilt index (TWI) through a series of physiological and biochemical changes. Melatonin pretreatment changed the expression level of MT synthesis genes which might contribute to MT synthesis in rice, consequently, activated the ROS scavenging system and alleviating the damage of alkaline stress on rice seedlings. Our study comprehensively understands the alleviating effect of exogenous melatonin on rice under alkaline stress.