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Human norovirus (HuNoV) is the most predominant viral agents of acute gastroenteritis. Point‐of‐care testing (POCT) based on lateral flow immunochromatography (LIFC) has become an important tool for rapid diagnosis of HuNoVs. However, low sensitivity and lack of quantitation are the bottlenecks of traditional LIFC. Thus, we established a rapid and accurate technique that combined immunomagnetic enrichment (IM) with LFIC to identify GII HuNoVs in fecal specimens. Before preparing immunofluorescent nanomagnetic microspheres and achieving the effect of HuNoV enrichment in IM and fluorescent signal in LFIC, amino‐functionalized magnetic beads (MBs) and carboxylated quantum dots (QDs) were coupled at a mass ratio of 4:10. Anti‐HuNoV monoclonal antibody was then conjugated with QDs‐MB. The limit of detection was 1.56 × 104 copies/mL, and the quantitative detection range was 1.56 × 104 copies/mL–1 × 106 copies/mL under optimal circumstances. The common HuNoV genotypes GII.2, GII.3, GII.4, and GII.17 can be detected, there was no cross‐reaction with various enteric viruses, including rotavirus, astrovirus, enterovirus, and sapovirus. A comparison between IM‐LFIC and RT‐qPCR for the detection of 87 fecal specimens showed a high level of agreement (kappa = 0.799). This suggested that the method is rapid and sensitive, making it a promising option for point‐of‐care testing in the future. [ABSTRACT FROM AUTHOR]

Norovirus is the primary foodborne pathogenic agent causing viral acute gastroenteritis. It possesses broad genetic diversity and the prevalence of different genotypes varies substantially. However, the differences in RNA‐dependent RNA polymerase (RdRp) activity among different genotypes of noroviruses remain unclear. In this study, the molecular mechanism of RdRp activity difference between the epidemic strain GII.17[P17] and the non‐epidemic strain GII.8[P8] was characterized. By evaluating the evolutionary history of RdRp sequences with Markov Chain Monte Carlo method, the evolution rate of GII.17[P17] variants was higher than that of GII.8[P8] variants (1.22 × 10−3 nucleotide substitutions/site/year to 9.31 × 10−4 nucleotide substitutions/site/year, respectively). The enzyme catalytic reaction demonstrated that the Vmax value of GII.17[P17] RdRp was 2.5 times than that of GII.8[P8] RdRp. And the Km of GII.17[P17] and GII.8[P8] RdRp were 0.01 and 0.15 mmol/L, respectively. Then, GII.8[P8] RdRp fragment mutants (A−F) were designed, among which GII.8[P8]‐A/B containing the conserved motif G/F were found to have significant effects on improving RdRp activity. The Km values of GII.8[P8]‐A/B reached 0.07 and 0.06 mmol/L, respectively. And their Vmax values were 1.34 times than that of GII.8[P8] RdRp. In summary, our results suggested that RdRp activities were correlated with their epidemic characteristics. These findings will ultimately provide a better understanding in replication mechanism of noroviruses and development of antiviral drugs. [ABSTRACT FROM AUTHOR]

• Axial back-and-forth-reflection (BFR) inside capillary was investigated. • A photometer based on axial -BFR inside capillary was proposed. • Optical-path enhancement of axial -BFR is more efficient than that of radial -BFR. • In comparison with radial -BFR, axial -BFR features low transmission loss. • The photometer features high sensitivity, compact, low cost and easy fabrication. As for photometry analysis, increasing the optical-path (OP) via multi-reflection is an effective method for improving the detection sensitivity. In this paper, a photometer based on axial multi-reflection between two end-faces of capillary was proposed and investigated. The probe light can be back and forth reflected inside the capillary, by employing apertured silver-mirrors at both ends of a metal-capillary. With designed aperture profile (i.e., a central disc-aperture and a peripheral ring-aperture) of the mirror, a 4.2-fold enhancement on OP was realized (i.e., OP is 4.2 times the capillary length). Moreover, the photometer was applied to detecting nitrite with a detection limit of 1 nM, which exhibits 8.6~15 fold improvement compared with that of previous photometers with similar capillary length and the same chromogenic reagent without sample enrichment. The photometer features compact, low cost and easy fabrication. [ABSTRACT FROM AUTHOR]

Human noroviruses (HuNoVs) have been found as the leading cause of acute gastroenteritis outbreaks in all age groups and are significantly correlated with the consumption of shellfish. In this study, the contamination of HuNoVs in shellfish was estimated through a systematic review and meta-analysis. Studies on the contamination of HuNoVs in shellfish were searched from PubMed, Web of Science, Embase, and Cochrane Library from January 2000 to August 2021. A total of 75 studies were included, and the pooled HuNoVs prevalence in shellfish was 29% (95% CI: 23–35) worldwide. As revealed by the results of the subgroup meta-analysis, the prevalence of dominant genogroup was variable, and 4% (95% CI: 3–6), 13% (95% CI: 10–17), with 7% (95% CI: 4–11) of the samples, respectively, contaminated by GI alone, GII alone, and GI&GII. The HuNoVs prevalence of shellfish in Europe, America, and Asia was 33% (95% CI: 24–43), 24% (95% CI: 7–47), and 27% (95% CI: 18–35), respectively, while only 10% (95% CI: 5–17) in Africa. Furthermore, the prevalence of HuNoVs in shellfish was the highest in spring (35%, 95% CI: 23–49) and winter (35%, 95% CI: 22–50), and the lowest in summer (11%, 95% CI: 5–18). Oysters, clams, and mussels had comparable HuNoVs prevalence of 28% (95% CI: 20–37), 27% (95% CI: 16–39) and 24% (95% CI: 17–32), respectively. The prevalence of HuNoVs in shellfish from harvest areas and markets was 30% (95% CI: 23–38) and 30% (95% CI: 19–41), respectively. The results of this study suggest a substantial burden of HuNoVs in shellfish worldwide, with GII.4 (92.86%) and GII.2 (46.43%) as the predominant genotypes. This study provides information regarding the contamination of HuNoVs in shellfish worldwide, which will contribute to the development of appropriate control measures to prevent shellfish-related HuNoVs gastroenteritis. • The pooled prevalence of human noroviruses in shellfish was found as 29% (95% CI: 23–35) worldwide. • GII.4 (92.86%, 26/28) was found as the most common genotype in shellfish. • Significant differences were found in the seasonal and geographical prevalence of human noroviruses in shellfish. [ABSTRACT FROM AUTHOR]

Oysters and mussels are important vectors for norovirus (NoV). An efficient pretreatment method for NoV detection in oysters based on ISO 15216-2:2019 was established in our previous work, but its effectiveness for other types of shellfish remains unknown. Therefore, this study systematically compared the differences between the standard and modified ISO methods in detecting NoV for oysters and mussels. Using the standard ISO method, the recovery rates of NoV in oysters (2.10 ± 0.80 %) and mussels (2.39 ± 0.56 %) were comparable (p > 0.05, unpaired t -test). In contrast, the virus recovery rates in oysters (19.83 ± 3.64 %) and mussels (46.96 ± 3.55 %) were both significantly improved by the modified method. Also, a significant difference was found between the virus recovery rates in two shellfish (p < 0.05, unpaired t -test), resulting in a 2.09-fold difference in their virus concentrations. Additionally, the limits of detection at 95 % probability of the modified ISO method for oysters and mussels could both reach 3.33 × 103 copies/g of digestive glands. Finally, the modified ISO method has been successfully applied in commercial oysters (14/27, 51.85 %) and mussels (15/23, 65.22 %), and the results indicated a significant difference in NoV recovery rates between two shellfish (p < 0.05, one-way analysis of variance). In summary, the modified ISO method showed higher virus recovery rates than the standard ISO method, which would be used as an essential tool for NoV detection in oysters and mussels. • We developed a new method that improves viral detection in oysters and mussels. • Our method provided a higher virus recovery rate than the standard ISO method. • There were significant differences in virus recovery between oysters and mussels using the new method. [ABSTRACT FROM AUTHOR]

• Non-epidemic norovirus genotype GII.8 virus-like particles (VLP) were expressed using the baculovirus-insect cell system. • Binding of GII.8 VLP to tissue blood group antigens (HBGAs) was observed. • The cross-reactivity of GII.8 VLP antiserum with other 27 (9 GI genotypes and 18 GII genotypes) capsid protein was evaluated. • Norovirus GII.8 strain antiserum had no cross-blocking effect on the binding of epidemic genotypes (GII.4, GII.17) to HBGA. • The existing vaccine candidate strain GI.1 antiserum and GII.4 antiserum had no cross-blocking effect on the binding of NoV GII.8 to HBGA. Noroviruses are causative agents of acute nonbacterial gastroenteritis epidemics worldwide. There are various genotypes, among which the non-epidemic genotype GII.8 can cause norovirus outbreaks. We previously demonstrated that the immunogenicity of GII.8 differed from that of epidemic variants. This study aimed to comprehensively compare the receptor profile and immunogenicity of the GII.8 variant with those of the epidemic variants. Using the baculovirus-insect cell expression system, we observed that recombinant capsid protein VP1 of the norovirus GII.8 GZ2017-L601 strain formed virus-like particles (VLPs) with a diameter of approximately 30 nm, as evidenced by transmission electron microscopy analysis. The GII.8 VLPs showed weak or moderate binding with all secretor histo-blood group antigens (HBGAs), but not with non-secretors, as evidenced by the HBGA-VLP binding test. The GII.8 VLP antiserum obtained from immunized BALB/c mice was tested for cross-reactivity with other norovirus genotypes (n = 28). The results showed that this antiserum demonstrated moderate cross-reactivity with GI.1, GII.3, and GII.15; however, no cross-reactivity with the epidemic variants of GII.2, GII.4, and GII.17 was observed. Additionally, the blocking-antibody activity of GII.8 antisera against GII.4 VLP-HBGAs and GII.17 VLP-HBGAs interactions and the cross-blocking of GII.8 VLP-HBGAs interactions by GI.1 and GII.4 antisera were evaluated using the HBGAs-VLP blocking test. However, no cross-blocking effect was observed. In summary, the characterization of norovirus GII.8 VLPs and derived antisera revealed that the GII.8 immunogenicity differed from that of epidemic variants. [ABSTRACT FROM AUTHOR]

In this paper, we present findings from four separate studies using different data sources and methods to examine Chinese attitudes toward the United States amid the COVID-19 pandemic. The empirical results consistently indicate a marked and significant decline in Chinese attitudes toward the US between late 2019 and the end of 2022. Using a quasi-experimental design and granular survey data that exploit daily variations in public opinion, we offer additional evidence that the decline in Chinese attitudes toward the United States followed a distinct pattern not true for Chinese attitudes toward other countries. Specifically, the rise in Chinese unfavorability toward the United States closely corresponded to the heightened Chinese attention to the pandemic's progression in the United States. These results collectively suggest a causal effect of COVID-19, shedding light on how public health crises, international relations, and media jointly shape the increasing enmity between the two great powers., Competing Interests: Competing interests statement:The authors declare no competing interest.

In order to increase the optical path and related sensitivity of photometers, multiple axial-reflection of parallel light-beam inside a capillary cavity is one of the most effective ways. However, there is a non-optimum trade-off between optical path and light intensity, e.g., smaller aperture on cavity mirror can increase multiple axial-reflection times (i.e., longer optical path) due to the lower cavity-loss, but it would also reduce coupling efficiency, light intensity, and related signal-to-noise ratio. Herein, an optical beam shaper, which is composed of two optical lenses with an apertured mirror, was proposed to focus the light beam (i.e., increasing coupling efficiency) without deteriorating beam parallelism and related multiple axial-reflection. Thus, by combining the optical beam shaper with a capillary cavity, large optical path enhancement (10-fold of capillary length) and high coupling efficiency (>65%) can be realized simultaneously, where the coupling efficiency was improved 50-fold. An optical beam shaper photometer (with a 7 cm long capillary) was fabricated and applied to detect water in ethanol with a detection limit of 12.5 ppm, which is 800-fold and 32∼80 fold lower than that of the commercial spectrometer (1 cm cuvette) and previous reports, respectively.

Objectives: We aimed to examine how COVID-19 incidence is associated with depressive symptoms in China, whether the association is transient, and whether the association differs across groups. Methods: We used a longitudinal sample from 2018 to 2020 waves of the China Family Panel Study. We constructed COVID-19 incidence rates as the number of new cases per 100,000 population in respondents' resident provinces in the past 7, 14, and 28 days when a respondent was surveyed. We performed linear or logistic regressions to examine the associations, and performed stratified analyses to explore the heterogeneity of the associations. Results: Our sample included 13,655 adults. The 7-day incidence rate was positively associated with the CES-D score (coef. = 2.551, 95% CI: 1.959-3.142), and likelihood of being more depressed (adjusted odds ratio = 6.916, 95% CI: 4.715-10.144). The associations were larger among those with less education, pre-existing depression, or chronic conditions. We did not find any significant association between the 14- or 28-day local incidence rates and depressive symptoms. Conclusion: The impact of COVID-19 incidence on mental health in China's general population was statistically significant and moderate in magnitude and transient. Disadvantaged groups experienced higher increases in depressive symptoms., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Zhou, Cai and Xie.)

Although noroviruses are the causative agents of most non-bacterial foodborne disease outbreaks, effective antivirals are currently unavailable. Certain probiotic strains have been reported as active antivirals for norovirus infections, but their mechanisms have not been fully elucidated. Herein, we examined the antiviral potential of 122 lactic acid bacteria isolates against murine norovirus (MNV), a human norovirus surrogate. A centenarian gut-derived strain, Limosilactobacillus fermentum PV22, exhibited the strongest MNV antagonism and reduced the viral titer by 2.23 ± 0.38 (log-value) in 5 min with stable activity at 25°C ( P < 0.01). Genome mining revealed that its antiviral activity can be attributed to the synthesis of γ-aminobutyric acid, and this finding was experimentally verified. Furthermore, we demonstrated the safety of the isolate and its high intestinal colonization ability. In conclusion, we discovered a centenarian gut-derived L. fermentum strain with strong anti-norovirus activity and identified its antiviral metabolite. Our results will offer new solutions for the prevention and treatment of food-related norovirus infections., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Li, Gao, Xue, Shang, Cai, Xie, Jiang, Chen, Zhang, Wang, Chen, Ding and Wu.)