Toxicity warning and online monitoring of disinfection by-products in water by electroautotrophic biocathode sensors.

As a result of the 2019 coronavirus pandemic, disinfection byproducts generated by the extensive use of chlorine disinfectants have infiltrated the aquatic environment, severely threatening ecological safety and human health. Therefore, the accurate monitoring of the biotoxicity of aqueous environments has become an important issue. Biocathode sensors are excellent choices for toxicity monitoring because of their special electroautotrophic respiration functions. Herein, a novel electroautotrophic biosensor with rapid, sensitive, and stable response and quantifiable output was developed. Its toxicity response was tested with typical disinfection byproducts dichloromethane, trichloromethane, and combinations of both, and corresponding characterization models were developed. Repeated toxicity tests demonstrated that the sensor was reusable rather being than a disposable consumable, which is a prerequisite for its long-term and stable operation. Microbial viability confirmed a decrease in sensor sensitivity due to microbial stress feedback to the toxicants, which is expected to be calibrated in the future by the standardization of the biofilms. Community structure analysis indicated that Moheibacter and Nitrospiraceae played an important role in the toxic response to chlorine disinfection byproducts. Our research provides technical support for protecting the environment and safeguarding water safety for human consumption and contributes new concepts for the development of novel electrochemical sensors.

Antiviral Drugs Screening for Swine Acute Diarrhea Syndrome Coronavirus.

Coronaviruses as possible cross-species viruses have caused several epidemics. The ongoing emergency of coronavirus disease 2019 (COVID-19) caused by SARS-CoV-2 has posed severe threats to the global economy and public health, which has generated great concerns about zoonotic viruses. Swine acute diarrhea syndrome coronavirus (SADS-CoV), an alpha-coronavirus, was responsible for mass piglet deaths, resulting in unprecedented economic losses, and no approved drugs or vaccines are currently available for SADS-CoV infection. Given its potential ability to cause cross-species infection, it is essential to develop specific antiviral drugs and vaccines against SADS-CoV. Drug screening was performed on a total of 3523 compound-containing drug libraries as a strategy of existing medications repurposing. We identified five compounds (gemcitabine, mycophenolate mofetil, mycophenolic acid, methylene blue and cepharanthine) exhibiting inhibitory effects against SADS-CoV in a dose-dependent manner. Cepharanthine and methylene blue were confirmed to block viral entry, and gemcitabine, mycophenolate mofetil, mycophenolic acid and methylene blue could inhibit viral replication after SADS-CoV entry. This is the first report on SADS-CoV drug screening, and we found five compounds from drug libraries to be potential anti-SADS-CoV drugs, supporting the development of antiviral drugs for a possible outbreak of SADS-CoV in the future.

Overview of Breastfeeding Under COVID-19 Pandemic.

During the global pandemic of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), pregnant and lactating women are at higher risk of infection. The potential of viral intrauterine transmission and vertical transmission by breastfeeding has raised wide concerns. Breastmilk is rich in nutrients that contribute to infant growth and development, and reduce the incidence rate of infant illness and death, as well as inhibit pathogens significantly, and protect infants from infection. Although it is controversial whether mothers infected with COVID-19 should continue to breastfeed, many countries and international organizations have provided recommendations and guidance for breastfeeding. This review presents the risks and benefits of breastfeeding for mothers infected with COVID-19, and the reasons for the absence of SARS-CoV-2 active virus in human milk. In addition, the antiviral mechanisms of nutrients in breastmilk, the levels of SARS-CoV-2 specific antibodies in breastmilk from COVID-19 infected mothers and vaccinated mothers are also summarized and discussed, aiming to provide some support and recommendations for both lactating mothers and infants to better deal with the COVID-19 pandemic.

COVID-19 vaccine development: milestones, lessons and prospects.

With the constantly mutating of SARS-CoV-2 and the emergence of Variants of Concern (VOC), the implementation of vaccination is critically important. Existing SARS-CoV-2 vaccines mainly include inactivated, live attenuated, viral vector, protein subunit, RNA, DNA, and virus-like particle (VLP) vaccines. Viral vector vaccines, protein subunit vaccines, and mRNA vaccines may induce additional cellular or humoral immune regulations, including Th cell responses and germinal center responses, and form relevant memory cells, greatly improving their efficiency. However, some viral vector or mRNA vaccines may be associated with complications like thrombocytopenia and myocarditis, raising concerns about the safety of these COVID-19 vaccines. Here, we systemically assess the safety and efficacy of COVID-19 vaccines, including the possible complications and different effects on pregnant women, the elderly, people with immune diseases and acquired immunodeficiency syndrome (AIDS), transplant recipients, and cancer patients. Based on the current analysis, governments and relevant agencies are recommended to continue to advance the vaccine immunization process. Simultaneously, special attention should be paid to the health status of the vaccines, timely treatment of complications, vaccine development, and ensuring the lives and health of patients. In addition, available measures such as mix-and-match vaccination, developing new vaccines like nanoparticle vaccines, and optimizing immune adjuvant to improve vaccine safety and efficacy could be considered.

Molnupiravir and Its Antiviral Activity Against COVID-19.

The coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) constitutes a major worldwide public health threat and economic burden. The pandemic is still ongoing and the SARS-CoV-2 variants are still emerging constantly, resulting in an urgent demand for new drugs to treat this disease. Molnupiravir, a biological prodrug of NHC (ß-D-N(4)-hydroxycytidine), is a novel nucleoside analogue with a broad-spectrum antiviral activity against SARS-CoV, SARS-CoV-2, Middle East respiratory syndrome coronavirus (MERS-CoV), influenza virus, respiratory syncytial virus (RSV), bovine viral diarrhea virus (BVDV), hepatitis C virus (HCV) and Ebola virus (EBOV). Molnupiravir showed potent therapeutic and prophylactic activity against multiple coronaviruses including SARS-CoV-2, SARS-CoV, and MERS-CoV in animal models. In clinical trials, molnupiravir showed beneficial effects for mild to moderate COVID-19 patients with a favorable safety profile. The oral bioavailability and potent antiviral activity of molnupiravir highlight its potential utility as a therapeutic candidate against COVID-19. This review presents the research progress of molnupiravir starting with its discovery and synthesis, broad-spectrum antiviral effects, and antiviral mechanism. In addition, the preclinical studies, antiviral resistance, clinical trials, safety, and drug tolerability of molnupiravir are also summarized and discussed, aiming to expand our knowledge on molnupiravir and better deal with the COVID-19 epidemic.

Exploration and practice of blended teaching of cell biology experiments during the COVID-19 epidemic.

Since 2019, new coronavirus pneumonia has been widespread worldwide and has had a direct impact on human life. Meanwhile, it also has a huge impact on teaching in universities and hospitals, especially in experimental courses. Cell biology is not only an important part of biology but also one of the most dynamic frontier branches of modern life science, which is also a science based on experiments. It is necessary to promote the online and offline teaching during this special period. To explore and evaluate the blended teaching modes during the COVID-19 epidemic, we changed the previous single teaching mode of "teaching + experiment" and published courseware and learning requirements online before class, this kind of mode takes "theory + virtual demonstration experiment" in class as the main body and the reviewing and thinking after class as the summary. We also carried out offline practice on a small scale when the epidemic allowed and actively explored the comprehensive online and offline teaching modes, in and out of class. Through the hybrid teaching, the percentage distribution of students in high and moderate scores ranges were greatly increased, the blended teaching mode also greatly improves students' subjective initiative and highlights the development of students' personalized thinking and scientific research ability. The practice of this model not only ensures the health of teachers and students during the epidemic but also provides a new teaching exploration model and thinking for the development of experimental courses during the epidemic.

Understanding the Secret of SARS-CoV-2 Variants of Concern/Interest and Immune Escape.

The global pandemic of the coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), places a heavy burden on global public health. Four SARS-CoV-2 variants of concern including B.1.1.7, B.1.351, B.1.617.2, and P.1, and two variants of interest including C.37 and B.1.621 have been reported to have potential immune escape, and one or more mutations endow them with worrisome epidemiologic, immunologic, or pathogenic characteristics. This review introduces the latest research progress on SARS-CoV-2 variants of interest and concern, key mutation sites, and their effects on virus infectivity, mortality, and immune escape. Moreover, we compared the effects of various clinical SARS-CoV-2 vaccines and convalescent sera on epidemic variants, and evaluated the neutralizing capability of several antibodies on epidemic variants. In the end, SARS-CoV-2 evolution strategies in different transmission stages, the impact of different vaccination strategies on SARS-CoV-2 immune escape, antibody therapy strategies and COVID-19 epidemic control prospects are discussed. This review will provide a systematic and comprehensive understanding of the secret of SARS-CoV-2 variants of interest/concern and immune escape.

The UV/H2O2 Process Based on H2O2 In-situ Generation for Water Disinfection

Till now, the unprecedented global spread of novel coronavirus disease (nCOVID-19) threatened human health, economy as well as ecosystem services gravely. An efficient disinfection technology is highly demanded. Ultraviolet (UV)/H2O2 process seems like a potential candidate, in which H2O2 is an indispensable oxidant for HO· species production. In this work, UV/H2O2, which coupled with in-situ generated H2O2, was demonstrated as an effective process for disinfection than UV, which would play a significant role in sterilization and disinfection for water treatment. In addition, we investigated the effects of catalyst layer (CL) calcination on the performance of two-electron oxygen reduction reaction (ORR) for H2O2 generation. It is found that the two-electron ORR activity can be intensified by avoiding calcination of CL, which can be mainly due to much oxygen functional groups (C − O and C = O) as well as higher conductivity and reaction kinetics.

Value of swab types and collection time on SARS-COV-2 detection using RT-PCR assay.

OBJECTIVE: Low viral load from patients infected with SARS-CoV-2 during infection late stage easily lead to false negative nucleic acid testing results, thus having great challenges to the prevention and control of the current pandemic. In present study, we mainly aimed to evaluate specimen types and specimen collection timepoint on the positive detection of 2019 novel coronavirus from patients at infection late stage based on RT-PCR testing. METHODS: Paired nasopharyngeal swabs, nasal swabs, oropharyngeal swabs and anal swabs were collected from patients infected with SARS-CoV-2 during infection late stage before washing in the morning and afternoon on the same day. Then virus RNA was extracted and tested for 2019-nCoV identification by RT-PCR within 24 h. RESULTS: Viral load was low at late infection stage. Specimens collected before washing in the morning would increase the detection ratio of 2019-nCoV. Detection ratio of nasopharyngeal swab [65 (95 % CI: 49.51-77.87) vs 42.5(95 % CI: 28.51-57.8)] or nasal swab [57.5 (95 % CI: 42.2-71.49) vs 35 (95 % CI: 22.13-50.49)] is higher not only than oropharyngeal swab[22.5 (95 % CI: 12.32-37.5) vs 7.5 (95 % CI: 2.58-19.86)], but also anal swab[2.5 (95 % CI: 0.44-12.88) vs 5 (95 % CI: 1.38-16.5)]. CONCLUSIONS: In summary, our research discovers that nasopharyngeal or nasal swab collected before washing in the morning might be more suitable for detecting of large-scale specimens from patients infected with low SARS-CoV-2 load during infection late stage. Those results could facilitate other laboratories in collecting appropriate specimens for improving detection of SARS-CoV-2 from patients during infection late stage as well as initially screening.