Prevalence of Mouse Norovirus in Experimental Mice in Beijing / 实验动物与比较医学

ObjectiveTo investigate the infection of mouse norovirus (MNV) in experimental mice raised under natural conditions from 19 biological companies in Beijing. MethodsThe mice used in this study were randomly selected from mice produced by 19 companies, and 14 mice of each strain and batch were combined into one cage, totaling 1 396 cages of 19 544 mice. The fecal samples from BALB/c, C57BL/6, ICR, KM, and BALB/c-nude mice were collected. TaqMan probe fluorescence quantitative PCR method was used to detect MNV infection of mice with MNV-1 primer, and whether the mice were infected with MNV was determined according to cycle threshold (Ct value). The chi-square test was used to analyze the difference of positive rate among the fecal samples from the five types of mice. The Ct values of the positive samples were statistically described; the non-parametric test was used to analyze the differences in Ct values among the five types of mice. Results A total of 1 396 fecal samples were collected. The positive rates of fecal MNV detection in BALB/c, C57BL/6, ICR, KM, and BALB/c-nude mice were 17.65%, 39.33%, 10.57%, 18.32% and 27.4%, respectively. According to the chi-square test results, the positive rate of fecal in C57BL/6 mice was higher than that in BALB/c, ICR, and KM mice (all P<0.05), and the positive rate of BALB/c-nude mice was higher than that in ICR and BALB/c mice (P<0.001, P＜0.05) . The viral load of BALB/c-nude or C57BL/6 mice was generally greater than that of KM mice (P<0.05). ConclusionMNV-1 primers can be applied to the detection of MNV infection in mice. The positive rate of MNV in five types of experimental mice in Beijing ranges from 10% to 40%, among which C57BL/6 mice and BALB/c-nude mice have higher positive rates of MNV than the others.

GP73 is a glucogenic hormone regulating SARS-CoV-2-induced hyperglycemia

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection induces new-onset diabetes and severe metabolic complications of pre-existing diabetes. The pathogenic mechanism underlying this is incompletely understood. Here, we provided evidence linking circulating GP73 with the exaggerated gluconeogenesis triggered by SARS-CoV-2 infection. We found that SARS-CoV-2 infection or glucotoxic condition increased the cellular secretion of GP73. Secreted GP73 trafficked to the liver and kidney to stimulate gluconeogenesis through cAMP/PKA pathway. By using global phosphoproteomics, we found a drastic remodeling of PKA kinase hub exerted by GP73. Notably, COVID-19 patients showed pathologically elevated plasma GP73, and neutralization of the secreted GP73 inhibited enhanced PKA signaling and glucose production associated with SARS-CoV-2 infection. GP73 blockade also reduced gluconeogenesis and lowered hyperglycemia in type 2 (T2D) diabetic mice. Therefore, our findings provide novel insight into the roles of GP73 as a key glucogenic hormone and mechanistic clues underlying the development of SARS-CoV-induced glucose abnormalities.

Evaluation of recombinant nucleocapsid and spike proteins for serological diagnosis of novel coronavirus disease 2019 (COVID-19)

BackgroundThe colloidal gold immunochromatography assay (GICA) is a rapid diagnostic tool for novel coronavirus disease 2019 (COVID-19) infections. However, with significant numbers of false negatives, improvements to GICA are needed. MethodsSix recombinant HCoV-19 nucleocapsid and spike proteins were prepared and evaluated. The optimal proteins were employed to develop a sandwich-format GICA strip to detect total antibodies (IgM and IgG) against HCoV-19. GICAs performance was assessed with comparison of viral RNA detection. ResultsRecombinant HCoV-19 proteins were obtained, including three prokaryotically expressed rN, rN1, rN2 nucleocapsid proteins, and three eukaryotically expressed rS1, rS-RBD, rS-RBD-mFc spike proteins. The recombinant proteins with the highest ELISA titers (rS1 and rS-RBD-mFc) against coronavirus-specific IgM and IgG were chosen for GICA development. The GICA has a sensitivity and specificity of 86.89% (106/122) and 99.39% (656/660), respectively. Furthermore, 65.63% (21/32) of the clinically confirmed but RT-PCR negative samples were GICA positive. ConclusionsThe eukaryotically-expressed spike proteins (rS1and rS-RBD-mFc) are more suitable than the prokaryotically expressed nucleocapsid proteins for HCoV-19 serological diagnosis. The GICA sandwich used to detect total antibodies is a powerful complement to the current standard RNA-based tests.

Detection of the Zaire Subtype of the Ebola Virus by Isothermal Multiple Self-matching Initiated Amplification / 病毒学报

Given the Ebola outbreak in West Africa and the risks of spread to other regions, a rapid, sensitive and simple method for the detection of the Ebola virus (EBOV) is of great significance for the prevention and control of Ebola. We developed a simple colorimetric isothermal multiple self-matching initiated amplification (IMSA) for rapid detection of the Zaire subtype of the Ebola virus (EBOV-Z). This method employed six primers that recognized seven sites of the EBOV-Z nucleoprotein gene for amplification of nucleic acids under isothermal conditions at 63 degrees C for 1 h. Amplification products were detected through visual inspection of color change by pre-addition of hydroxyl naphthol blue dye. Relative sensitivity was validated by detection of serial tenfold dilutions of virus-like particles containing the partial EBOV-Z nucleoprotein gene and mock clinical sample. Specificity of IMSA was validated by detection of the plasma of 30 healthy volunteers, the dengue virus, and Japanese encephalitis virus. IMSA had comparable sensitivity to Reverse transcription-quantitative polymerase chain reaction (RT-qPCR), and cross-reaction with human plasma or other viruses was not observed. Reverse transcription-isothermal multiple self-matching initiated amplification (RT-IMSA) was also evaluated and compared in parallel with the commercial RT-qPCR kit for detection of EBOV-suspected samples of human blood in Sierra Leone. Sensitivity and specificity of the RT-IMSA was 91.4% and 100%, respectively. These data suggest that RT-IMSA is a valuable tool for the detection of the EBOV with the distinct advantages of simplicity and low cost compared with RT-qPCR.

Identification of novel transcripts and sRNA of Brucella melitensis by RNA-Seq / 中国人兽共患病学报

To identify novel transcripts and sRNA in genome of B .melitensis by transcriptome sequencing ,total RNA were extracted from B .melitensis culture and rRNA were removed .After the addition of adaptor ,RNA was reversely transcribed into cDNA ,which were then subjected to PCR amplification and sequencing .The generated reads were mapped to genome se‐quence of B .melitensis strain 16M .With the mapping results ,novel transcripts and sRNA were identified by bioinformatics methods .Sequencing results analysis showed that genome sequence was covered with the reads with good quality .A total of 773 genes were extended in their 5′and/or 3′ends of their original locations .Sixteen novel transcripts and 241 sRNAs candi‐dates were identified .RT‐PCR showed that some of the sRNAs were differentially expressed under stress conditions .In B . melitensis genome ,there is novel transcript which is not predicted .The sRNA does exist in B .melitensis and were expressed under different conditions .

Determination of OH Radicals in Acid Oxidation-Potential Water by Electron Paramagnetic Resonance / 环境与健康杂志

Objective To investigate whether ?OH radical species present in the acid oxidation-potential water (AOW). Methods Electron paramagnetic resonance spectroscopy (EPR) coupled with the spin trapping technique was used for determination of ?OH radicals. Results A seven-line spectrum characteristic of 5, 5-dimethyl-2-pyrrolidone-N-oxyl (DMPOX) was formed at first, at 60 min the spin adducted DMPO-OH with four-line spectrum characteristic and at 120 min, no spectrum was observed. Conclusion ?OH can be detected in AOW at 60 min and it may come from the interaction of active substance in the AOW.