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Many prokaryotic viruses are temperate and their reactivation is tightly regulated. However, except for a few bacterial model systems, the regulatory circuits underlying the exit from lysogeny are poorly understood, especially in archaea. Here, we report a three-gene module which regulates the switch between lysogeny and replicative cycle in a haloarchaeal virus SNJ2 (family Pleolipoviridae). The SNJ2 orf4 encodes a winged helix-turn-helix DNA binding protein which maintains lysogeny through repressing the expression of the viral integrase gene intSNJ2. To switch to the induced state, two other SNJ2-encoded proteins, Orf7 and Orf8, are required. Orf8 is a homolog of cellular AAA+ ATPase Orc1/Cdc6, which is activated upon mitomycin C-induced DNA damage, possibly through posttranslational modification. Activated Orf8 initiates the expression of Orf7 which, in turn, antagonizes the function of Orf4, leading to the transcription of intSNJ2, thereby switching SNJ2 to the induced state. Comparative genomics analysis revealed that the SNJ2-like Orc1/Cdc6-centered three-gene module is common in haloarchaeal genomes, always present in the context of integrated proviruses. Collectively, our results uncover the first DNA damage signaling pathway encoded by a temperate archaeal virus and reveal an unexpected role of the widely distributed virus-encoded Orc1/Cdc6 homologs.

Duck is commonly used for premium meat adulteration. A simple, rapid, accurate, and affordable method is urgently needed for duck ingredient identification. Therefore, we developed two recombinase polymerase amplification (RPA) assays based on the duck-specific Cytb gene for rapid detection of duck ingredient in this study, and there were less than 30 min from sample to answer. Two RPA assays were validated to demonstrate good inter- and intra-species specificity. The real-time RPA could detect as low as 10 pg of duck DNA while the RPA combined with lateral flow test strips (LFS RPA) could detect down to 1 pg, and both could detect 0.1% duck meat adulteration. Then the two RPA assays applicability was confirmed using 113 different foods. The effects of background DNA and whole blood on RPA amplification were also analyzed, which did not affect the feasibility of the developed two RPA assays. The developed real-time RPA and LFS RPA would be promising user-friendly on-site detection methods for rapid detecting duck ingredient in different meat products.

Conventional AVO inversion employs Zoeppritz equations and various approximations to them to obtain the reflection coefficients of plane-waves, which are confined to a certain (small) angle range (mostly below $$40^{\circ }$$). However, near the critical angles (wide-angle), reflections at the post-critical angles provide much more potential for velocity and density inversion because of the large amplitudes and phases-shifted waveforms, while the Zoeppritz equations are not applicable anymore. Hence, there is a strong demand for the research into wide-angle AVO. With reflection coefficients at wide-angle corresponding to the features of rational function, we try to approximate the seismic data with vector fitting which is used to obtain the rational zero-pole and residual properties of wide-angle AVO. We apply this technique to classify AVO type and recognize the lithology. Our experiment shows that extending our research into wide-angle AVO is very promising in gathering richer data for a more accurate seismic analysis.

Background Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has become a public health emergency of international concern. SARS-CoV-2 RNA detection is the diagnostic criterion for coronavirus disease 2019 (COVID-19). Nevertheless, RNA detection has many limitations, such as being time-consuming and cost-prohibitive, and it must be performed in specialized laboratories. Virus antibody detection is a routine method for screening for multiple viruses, but data about SARS-CoV-2 antibody detection are limited. Method Throat swabs and blood were collected from 67 suspected SARS-CoV-2 infection patients at the Affiliated Hospital of Zunyi Medical University and Zunyi Fourth People’s Hospital isolated observation departments. Throat swab samples were subjected to SARS-CoV-2 RNA detection by real-time PCR. Blood was used subjected to SARS-CoV-2 IgG/IgM detection by an enzyme-linked immunosorbent assay (ELISA) and gold immunochromatography assay (GICA). Blood underwent C-reactive protein detection by immunoturbidimetry, and white blood cells, neutrophil percentages and lymphocyte percentages were counted and calculated, respectively. Clinical symptoms, age and lifestyle habits (smoking and drinking) in all patients were recorded. Data were analysed using SPSS version 19. The results were confirmed by T and χ2 tests; correlations with detection results were analysed by kappa coefficients. Odds ratio (OR) and corrected OR values were analysed by logistic regression. P Results Of the 67 patients included in this study, 26 were SARS-CoV-2 RNA-positive. GICA IgM sensitivity was 50.9% (13/26), and specificity was 90.2% (37/41). ELISA IgM sensitivity was 76.9% (20/26), and specificity was 90.2% (37/41). ELISA IgG sensitivity was 76.9% (20/26), and specificity was 95.1% (39/41). The kappa coefficients between RNA detection and ELISA IgG, ELISA IgM, and GICA IgM results were 0.741 (P P < 0.01) and 0.430 (P < 0.01), respectively. Conclusion Among the candidate blood indicators, serum IgG and IgM detected by ELISA had the best consistency and validity when compared with standard RNA detection; these indicators can be used as potential preliminary screening tools to identify those who should undergo nucleic acid detection in laboratories without RNA detection abilities or as a supplement to RNA detection.

Background Radiation-induced insufficiency fractures (IF) is frequently occult without fracture line, which may be mistaken as metastasis. Quantitative apparent diffusion coefficient (ADC) shows potential value for characterization of benign and malignant bone marrow diseases. The purpose of this study was to develop a nomogram based on multi-parametric ADCs in the differntiation of occult IF from bone metastasis after radiotherapy (RT) for cervical cancer. Methods This study included forty-seven patients with cervical cancer that showed emerging new bone lesions in RT field during the follow-up. Multi-parametric quantitative ADC values were measured for each lesion by manually setting region of interests (ROIs) on ADC maps, and the ROIs were copied to adjacent normal muscle and bone marrow. Six parameters were calculated, including ADCmean, ADCmin, ADCmax, ADCstd, ADCmean ratio (lesion/normal bone) and ADCmean ratio (lesion/muscle). For univariate analysis, receiver operating characteristic curve (ROC) analysis was performed to assess the performance. For combined diagnosis, a nomogram model was developed by using a multivariate logistic regression analysis. Results A total of 75 bone lesions were identified, including 48 occult IFs and 27 bone metastases. There were significant differences in the six ADC parameters between occult IFs and bone metastases (p std and ADCmean ratio (lesion/muscle) were identified as independent factors and were selected to generate a nomogram model. The nomogram model showed a better performance, yielded an AUC of 0.92, the sensitivity of 91.7%, the specificity of 96.3%, positive predictive value (PPV) of 97.8% and negative predictive value (NPV) of 86.7%, respectively. Conclusions Multi-parametric ADC values demonstrate potential value for differentiating occult IFs from bone metastasis, a nomogram based on the combination of ADCstd and ADCmean ratio (lesion/muscle) may provide an improved classification performance.

BackgroundSevere acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a new type of virus that firstly confirmed in Wuhan, China recently. SARS-CoV-2 mainly spread through droplets. Infection characteristics data of SARS-CoV-2 is still limited, especially about asymptomatic infection, familial aggregation infection and infection risk in family member.MethodsFrom 2nd January 2020 to 23th February 2020, we have screened 22,729 throat swab samples from individuals with either have contact history of imported personnel, out-of-city travel or residence history or flu-like symptoms during the past 14 days. SARS-CoV-2 RNA was extracted and detected by real-time PCR. Data were analyzed using SPSS version 19 (IBM, Armonk, NY, USA). The results were confirmed by the Pearson χ2 test; P ＜ 0.05 was considered statistically significant.Results35 SARS-CoV-2 positive patients were found, 22 were asymptomatic infection, and 31 were familial aggregation infection. Odds ratio of SARS-CoV-2 infection risk between family aggregated close contacts and overall close contacts was 29.40 (95％ confidence interval: 13.99 - 62.205, χ2 = 140.23, P ＜ 0.001); odds ratio of SARS-CoV-2 infection risk between family aggregated close contacts and non-family aggregated close contacts was 703.50 （95％ confidence interval: 89.53 - 5527.95, χ2 = 282.659, P ＜ 0.001). One SARS-CoV-2 positive patient infected 2.08 (25/12) people on average under social control without separate isolation.ConclusionsSocial control is effective in SARS-CoV-2 inhibition, but self-isolation and screening should be added as supplementary means to avoid familial aggregation infection and find out asymptomatic patients.

Okra is widely used as vegetable, food ingredient, and traditional medicine in China for various applications. The main healthy properties are accepted to originate from the high polysaccharide content of okra. In this study, a homogenous pectic polysaccharide WOP-2 was extracted, isolated, and purified from okra by DEAE-cellulose and Sepharose CL-6B column, and its molecular weight was estimated to be 580 kDa. Monosaccharide composition was analyzed to be Rha (21.4%), GalA (34.9%), Gal (29.6%), GlcA (4.5%), Glc (5.9%), and Ara (3.7%) by HPLC with PMP derivatization. Combined with NMR analysis, WOP-2 was elucidated to be a rhamnogalacturonan I backbone with type-II arabinogalactan side-chains substituted partly at O-4 of Rhap. WOP-2 exhibits significant anti-hyperglycemic activity on STZ-induced diabetic mice by inhibiting the lipid peroxidation chain reaction probably. Overall, these results provide new insight into structure–activity relationships of polysaccharide from okra and provide impetus towards the development of polysaccharide-based therapeutics on diabetes.

In order to eliminate the shielding effect of the coal seam on the sand body, better predict the sand body, comprehensively apply the seismic forward modeling method and frequency division technology to extract the low frequency signal in the suitable frequency range, the seismic information of the coal seam can be filtered out, and the sand body is retained. There is a school signal, and then according to the matching relationship between the low frequency signal and the sand body, the distribution range of the sand body can be well predicted, and then the seismic inversion method and the logging data of the new drilling are used to verify whether the sand body distribution is reasonable. The results show that the sand body interpretation conclusion of single well logging data has a good correspondence with the sand body distribution range predicted by reservoir prediction based on seismic low frequency properties. In the absence of well data to participate in the calculation, the reservoir prediction method based on the low-frequency properties of the earthquake can directly reflect the distribution range of the sand body, and the reliability of the predicted sand body boundary range is higher.