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1.
Read Writ ; 35(8): 1975-2014, 2022.
Article in English | MEDLINE | ID: covidwho-1942511

ABSTRACT

The current study examined how Chinese characters were taught by primary grade teachers in Macao during online instruction resulting from the COVID-19 pandemic (i.e., emergency remote instruction). A random sample of 313 first to third grade teachers in public and private schools were surveyed about their instructional practices. Most teachers surveyed (72%) reported they taught a lesson about Chinese characters once every 3-4 weeks during emergency remote instruction, and 83% and 81% of teachers indicated they assigned homework for writing and reading characters, respectively, at the same rate. On average, they reportedly spent 97 min per week teaching students to write, read, and understand the meaning of new characters, devoting equal time to each of these skills. They also indicated students practiced writing and reading characters in class for 40 min per week. They further noted students were expected to spend 35 min a day practicing writing and reading characters for homework. While teachers reportedly used a variety of instructional practices for teaching characters (M = 30.38), the typical teacher applied less than one-half (N = 64) of practices assessed. Teachers reported use of asynchronous (online learning activities which can be completed at other times) and synchronous (real-time videos and audio/text) teaching methods and perceptions of adequacy of technical support predicted reported teaching practices. The findings from this study raise questions about the teaching of Chinese characters in Macao during emergency remote instruction.

2.
J Virol ; 96(14): e0065322, 2022 07 27.
Article in English | MEDLINE | ID: covidwho-1938007

ABSTRACT

Infectious bronchitis virus (IBV) is an avian coronavirus that causes infectious bronchitis, an acute and highly contagious respiratory disease of chickens. IBV evolution under the pressure of comprehensive and widespread vaccination requires surveillance for vaccine resistance, as well as periodic vaccine updates. Reverse genetics systems are very valuable tools in virology, as they facilitate rapid genetic manipulation of viral genomes, thereby advancing basic and applied research. We report here the construction of an infectious clone of IBV strain Beaudette as a bacterial artificial chromosome (BAC). The engineered full-length IBV clone allowed the rescue of an infectious virus that was phenotypically indistinguishable from the parental virus. We used the infectious IBV clone and examined whether an enhanced green fluorescent protein (EGFP) can be produced by the replicase gene ORF1 and autocatalytically released from the replicase polyprotein through cleavage by the main coronavirus protease. We show that IBV tolerates insertion of the EGFP ORF at the 3' end of the replicase gene, between the sequences encoding nsp13 and nsp16 (helicase, RNA exonuclease, RNA endonuclease, and RNA methyltransferase). We further show that EGFP is efficiently cleaved from the replicase polyprotein and can be localized in double-membrane vesicles along with viral RNA polymerase and double-stranded RNA, an intermediate of IBV genome replication. One of the engineered reporter EGFP viruses were genetically stable during passage in cultured cells. We demonstrate that the reporter EGFP viruses can be used to study virus replication in host cells and for antiviral drug discovery and development of diagnostic assays. IMPORTANCE Reverse genetics systems based on bacterial artificial chromosomes (BACs) are the most valuable systems in coronavirus research. Here, we describe the establishment of a reverse genetics system for the avian coronavirus strain Beaudette, the most intensively studied strain. We cloned a copy of the avian coronavirus genome into a BAC vector and recovered infectious virus in permissive cells. We used the new system to construct reporter viruses that produce enhanced green fluorescent protein (EGFP). The EGFP coding sequence was inserted into 11 known cleavage sites of the major coronavirus protease in the replicase gene ORF1. Avian coronavirus tolerated the insertion of the EGFP coding sequence at three sites. The engineered reporter viruses replicated with parental efficiency in cultured cells and were sufficiently genetically stable. The new system facilitates functional genomics of the avian coronavirus genome but can also be used for the development of novel vaccines and anticoronaviral drugs.


Subject(s)
Coronavirus Infections , Infectious bronchitis virus , Reverse Genetics , Animals , Chickens , Coronavirus Infections/veterinary , Genes, Reporter , Green Fluorescent Proteins , Infectious bronchitis virus/genetics , Peptide Hydrolases , Polyproteins , RNA, Viral/genetics
3.
EuropePMC; 2020.
Preprint in English | EuropePMC | ID: ppcovidwho-325536

ABSTRACT

Coronaviruses are identify in different species of animals, including camels, bats and avian. Avian infectious bronchitis virus (IBV) always infect and invade from the respiratory tract, where submucosal dendritic cells (DCs) are the first guard to defend it. However, different IBV subtypes, such as QX and M41, could suppress the function of dendritic cells and escape the degradation and presentation, which might help coronaviruses to transfer and migrant. Hence, it is necessary to illustrate the uncovered mechanisms how IBV inhibited the antigen-presentation of avian DCs. Initially, we compared two types IBV's function in activating avian bone marrow dendritic cells (BMDCs) and found that both IBV (QX and M41) did not significantly increase the expression of MHCII. Subsequent global analyses identified 21 significantly different expressed (DE) microRNAs and 2888 DE long non-coding RNAs (lncRNAs) in IBV M41 stimulated group, while IBV (QX) stimulation only identified 4 DE microRNAs and 1782 DE lncRNAs. Moreover, GO and KEGG analysis of microRNAs target and lncRNAs lead to endocytosis and cytokine-cytokine receptor interaction, which might contribute to the differences in pathogenicity of QX and M41. Meantime, a significant decrease of the m 6 A modification level in mRNA, but an increased in the ut RNA were observed in avian BMDCs upon the prevalent IBV (QX) infection. Interestingly, an opposite consequence was seen in avian BMDCs during the IBV (M41) infection. Further study found that both non-structural protein 7 (NSP7) and NSP16 inhibited the maturation and cytokines secretion of BMDCs, as well as their antigen-presentation ability. Lastly, we found that gga-miR21, induced and increased by both NSP7 and NSP16, inhibited the antigen presentation of avian BMDCs. Taken together, our results illustrated how IBV inhibited the antigen-presentation of avian DCs and provide a clue for the systemic transmission of the COVID-19.Funding Statement: This work was supported by the National Key Research and Development Program of China (2017YFD500706), the Jiangsu Excellent Youth Natural Science Foundation (BK20190077), the National Natural Science Foundation of China (No. 31702197) to J.L. Moreover, this work was also supported by National Natural Science Foundation of China (31930109 and 31772777), the Fundamental Research Funds for the Central Universities (JCQY201906) and A Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD) to Q.Y and Q.HY. Furthermore, this work was financially supported by the Fundamental Research Funds for the Central Universities (KJQN202060), the National Natural Science Foundation of China (31900907), the Natural Science Foundation of Jiangsu Province (BK20190528) to M.CDeclaration of Interests: The authors of this editorial have no conflicts of interest to declare. The authors have no other relevant affiliations or financial involvement in any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.Ethics Approval Statement: This study was approved by the Ethics Committee of Animal Experiments center of Nanjing Agricultural University. All animal studies were approve by the Institutional Animal Care and Use Committee of Nanjing Agricultural University (SYXK-2017-0007), and followed the National Institutes of Health guidelines for the performance of animalexperiments.

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