Licorice-saponin A3 is a broad-spectrum inhibitor for COVID-19 by targeting viral spike and anti-inflammation

Currently,human health due to corona virus disease 2019(COVID-19)pandemic has been seriously threatened.The coronavirus severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)spike(S)protein plays a crucial role in virus transmission and several S-based therapeutic approaches have been approved for the treatment of COVID-19.However,the efficacy is compromised by the SARS-CoV-2 evolvement and mutation.Here we report the SARS-CoV-2 S protein receptor-binding domain(RBD)inhibitor licorice-saponin A3(A3)could widely inhibit RBD of SARS-CoV-2 variants,including Beta,Delta,and Omicron BA.1,XBB and BQ1.1.Furthermore,A3 could potently inhibit SARS-CoV-2 Omicron virus in Vero E6 cells,with EC50 of 1.016μM.The mechanism was related to binding with Y453 of RBD determined by hydrogen-deuterium exchange mass spectrometry(HDX-MS)analysis combined with quantum mechanics/molecular mechanics(QM/MM)simulations.Interestingly,phosphoproteomics analysis and multi fluorescent immunohistochemistry(mIHC)respectively indicated that A3 also inhibits host inflammation by directly modulating the JNK and p38 mitogen-activated protein kinase(MAPK)pathways and rebalancing the corresponding immune dysregulation.This work supports A3 as a promising broad-spectrum small molecule drug candidate for COVID-19.

Rapid Detection of Filoviruses by Real-time TaqMan Polymerase Chain Reaction Assays

Ebola virus （EBOV） and Marburg virus （MARV） are causative agents of severe hemorrhagic fever with high mortality rates in humans and non-human primates and there is currently no licensed vaccine or therapeutics. To date, there is no specific laboratory diagnostic test in China, while there is a national need to provide differential diagnosis during outbreaks and for instituting acceptable quarantine procedures. In this study, the TaqMan RT-PCR assays targeting the nucleoprotein genes of the Zaire Ebolavirus （ZEBOV） and MARV were developed and their sensitivities and specificities were investigated. Our results indicated that the assays were able to make reliable diagnosis over a wide range of virus copies from 103 to 109, corresponding to the threshold of a standard RNA transcript. The results showed that there were about 101 RNA copies per milliliter of virus culture supernatant, equivalent to 10,000 RNA molecules per infectious virion, suggesting the presence of many non-infectious particles. These data indicated that the TaqMan RT-PCR assays developed in this study will be suitable

Isolation and complete genome sequence of a novel virulent mycobacteriophage, CASbig

Dear Editor,Bacteriophages are powerful tools for investigating and manipulating their hosts(Fernandes et al.,2014).This holds particularly true for mycobacteriophages,which have facilitated the development of mycobacterial genetic systems and have generated tools for the clinical

Molecular dissection of phage lysin PlySs2: integrity of the catalytic and cell wall binding domains is essential for its broad lytic activity

The novel phage lysin PlySs2, is reported to be highly active against various bacteria, including staphylococci, streptococci and Listeria. However, the molecular mechanisms underlying its broad lytic spectrum remain to be established. In the present study, the lytic activity of the catalytic domain(CD, PlySc) and binding specificity of the cell wall binding domain(CBD, PlySb) of PlySs2 were examined. Our results showed that PlySc alone maintains very limited lytic activity. Enhanced green fluorescent protein(EGFP)-fused PlySb displayed high binding affinity to the streptococcal strains tested, including S.suis, S.dysgalactiae, and S.agalactiae, but not staphylococci, supporting its utility as a good CBD donor for streptococcal-targeted lysin engineering. EGFP-fused intact PlySs2 similarly displayed high affinity for streptococci, but not staphylococci. Notably, four truncated PlySb fragments showed no binding capacity. These findings collectively indicate that integrity of the PlySc and PlySb domains is an essential determinant of the broad lytic activity of PlySs2.

Developing a bacteriophage cocktail for biocontrol of potato bacterial wilt

Bacterial wilt is a devastating disease of potato and can cause an 80% production loss. To control wilt using bacteriophage therapy, we isolated and characterized twelve lytic bacteriophages from different water sources in Kenya and China. Based on the lytic curves of the phages with the pathogen Ralstonia solanacearum, one optimal bacteriophage cocktail, P1, containing six phage isolations was formulated and used for studying wilt prevention and treatment efficiency in potato plants growing in pots. The preliminary tests showed that the phage cocktail was very effective in preventing potato bacterial wilt by injection of the phages into the plants or decontamination of sterilized soil spiked with R. solanacearum. Eighty percent of potato plants could be protected from the bacterial wilt(caused by R. solanacearum reference strain GIM1.74 and field isolates), and the P1 cocktail could kill 98% of live bacteria spiked in the sterilized soil at one week after spraying.However, the treatment efficiencies of P1 depended on the timing of application of the phages, the susceptibility of the plants to the bacterial wilt, as well as the virulence of the bacteria infected,suggesting that it is important to apply the phage therapy as soon as possible once there are early signs of the bacterial wilt. These results provide the basis for the development of bacteriophagebased biocontrol of potato bacterial wilt as an alternative to the use of antibiotics.

Bacteriophages Isolated in China for the Control of Pectobacterium carotovorum Causing Potato Soft Rot in Kenya

Soft rot is an economically significant disease in potato and one of the major threats to sustainable potato production.This study aimed at isolating lytic bacteriophages and evaluating methods for and the efficacy of applying phages to control potato soft rot caused by Pectobacterium carotovorum.Eleven bacteriophages isolated from soil and water samples collected in Wuhan,China,were used to infect P.carotovorum host strains isolated from potato tubers showing soft rot symptoms in Nakuru county,Kenya.The efficacy of the phages in controlling soft rot disease was evaluated by applying individual phage strains or a phage cocktail on potato slices and tubers at different time points before or after inoculation with a P.carotovorum strain.The phages could lyse 20 strains of P.carotovorum,but not Pseudomonas fluorescens control strains.Among the 11 phages,Pectobacterium phage Wc5r,interestingly showed cross-activity against Pectobacterium atrosepticum and two phage-resistant P.carotovorum strains.Potato slice assays showed that the phage concentration and timing of application are crucial factors for effective soft rot control.Phage cocktail applied at a concentration of 1×10^9 plaque-forming units per milliliter before or within an hour after bacterial inoculation on potato slices,resulted in>90%reduction of soft rot symptoms.This study provides a basis for the development and application of phages to reduce the impact of potato soft rot disease.

Schaftoside inhibits 3CL^(pro)and PL^(pro)of SARS-CoV-2 virus and regulates immune response and inflammation of host cells for the treatment of COVID-19

It is an urgent demand worldwide to control the coronavirus disease 2019(COVID-19)pandemic caused by the severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)virus.The 3-chymotrypsin-like protease(3CL^(pro))and papain-like protease(PL^(pro))are key targets to discover SARS-CoV-2 inhibitors.After screening 12 Chinese herbal medicines and 125 compounds from licorice,we found that a popular natural product schaftoside inhibited 3CL^(pro)and PL^(pro)with IC_(50)values of 1.73±0.22 and 3.91±0.19μmol/L,respectively,and inhibited SARS CoV-2 virus in Vero E6 cells with EC_(50)of 11.83±3. 23μmol/L. Hydrogen-deuterium exchange mass spectrometry analysis, quantum mechanics/molecular mechanics calculations, together with site-directed mutagenesis indicated the antiviral activities of schaftoside were related with non-covalent interactions with H41, G143 and R188 of3CLpro, and K157, E167 and A246 of PLpro. Moreover, proteomics analysis and cytokine assay revealed that schaftoside also regulated immune response and inflammation of the host cells. The antiinflammatory activities of schaftoside were confirmed on lipopolysaccharide-induced acute lung injury mice. Schaftoside showed good safety and pharmacokinetic property, and could be a promising drug candidate for the prevention and treatment of COVID-19.

Enriched Opportunistic Pathogens Revealed by Metagenomic Sequencing Hint Potential Linkages between Pharyngeal Microbiota and COVID-19

As a respiratory tract virus,SARS-CoV-2 infected people through contacting with the upper respiratory tract first.Previous studies indicated that microbiota could modulate immune response against pathogen infection.In the present study,we performed metagenomic sequencing of pharyngeal swabs from eleven patients with COVID-19 and eleven Non-COVID-19 patients who had similar symptoms such as fever and cough.Through metagenomic analysis of the above two groups and a healthy group from the public data,there are 6502 species identified in the samples.Specifically,the Pielou index indicated a lower evenness of the microbiota in the COVID-19 group than that in the Non-COVID-19 group.Combined with the linear discriminant analysis(LDA)and the generalized linear model,eighty-one bacterial species were found with increased abundance in the COVID-19 group,where 51 species were enriched more than 8 folds.The top three enriched genera were Streptococcus,Prevotella and Campylobacter containing some opportunistic pathogens.More interestingly,through experiments,we found that two Streptococcus strains,S.suis and S.agalactiae,could stimulate the expression of ACE2 of Vero cells in vitro,which may promote SARS-CoV-2 infection.Therefore,these enriched pathogens in the pharynxes of COVID-19 patients may involve in the virus-host interactions to affect SARS-CoV-2 infection and cause potential secondary bacterial infections through changing the expression of the viral receptor ACE2 and/or modulate the host’s immune system.

Extensive evolution analysis of the global chikungunya virus strains revealed the origination of CHIKV epidemics in Pakistan in 2016

Chikungunya virus(CHIKV) is a mosquito-borne virus that causes epidemics widely in the world especially in the tropical and subtropical regions. Phylogenetic analysis has found that the CHIKV lineages were associated with the spatial and temporal distributions, which were related to the virus adaption to the major mosquito species and their distributions. In this study, we reported the complete genome sequences of eight CHIKV isolates from the outbreak in Pakistan last year. Then we reviewed the evolutionary history using extensive phylogenetic analysis, analyzed lineagespecific substitutions in viral proteins, and characterized the spreading pathway of CHIKV strains including the Pakistani strains. The results showed that the Pakistani stains belonged to the ECSA.IOL sub-lineage and derived from India. The genetic properties of the Pakistani strains including the adaptive substitution to vectors were further characterized, and the potential risks from the occurrence of CHIKV infection in Pakistan were discussed. These results provided better understanding of CHIKV evolution and transmission in the world and revealed the possible origination of the CHIKV outbreak and epidemic in Pakistan, which would promote the disease prevention and control in the identified countries and territories with the history of CHIKV infections as well as new regions with potential risk of CHIKV outbreaks.

Nanopore sequencing of African swine fever virus

Dear Editor,African swine fever(ASF)is one of the most pathogenic viral diseases in pigs caused by African swine fever virus(ASFV).The fatality rate is almost 100%,which brings huge economic losses to the hog industry in countries with epiepidemics(Galindo and Alonso,2017).China was the first Asian country to have an ASF epidemic,and it spread quickly across the country after the first epidemic was re・ported in August 2018(Ge et al.,2018).After that,Mongolia,Vietnam,Cambodia and North Korea also reported on the ASF epidemic in succession(OIE,2019).

Increased pathogenicity and aerosol transmission for one SARS-CoV-2 B.1.617.2 Delta variant over the wild-type strain in hamsters

During the two-year pandemic of coronavirus disease 2019(COVID-19), its causative agent, severe acute respiratory syndrome coronavirus 2(SARS-CoV-2), has been evolving. SARS-CoV-2 Delta, a variant of concern, has become the dominant circulating strain worldwide within just a few months. Here, we performed a comprehensive analysis of a new B.1.617.2 Delta strain(Delta630) compared with the early WIV04 strain(WIV04) in vitro and in vivo, in terms of replication, infectivity, pathogenicity, and transmission in hamsters. When inoculated intranasally, Delta630 led to more pronounced weight loss and more severe disease in hamsters. Moreover, 40%mortality occurred about one week after infection with 10^(4)PFU of Delta630, whereas no deaths occurred even after infection with 10^(5)PFU of WIV04 or other strains belonging to the Delta variant. Moreover, Delta630outgrew over WIV04 in the competitive aerosol transmission experiment. Taken together, the Delta630 strain showed increased replication ability, pathogenicity, and transmissibility over WIV04 in hamsters. To our knowledge, this is the first SARS-CoV-2 strain that causes death in a hamster model, which could be an asset for the efficacy evaluation of vaccines and antivirals against infections of SARS-CoV-2 Delta strains. The underlying molecular mechanisms of increased virulence and transmission await further analysis.

Rapid Acquisition of High-Quality SARS-CoV-2 Genome via Amplicon-Oxford Nanopore Sequencing

Genome sequencing has shown strong capabilities in the initial stages of the COVID-19 pandemic such as pathogen identification and virus preliminary tracing.While the rapid acquisition of SARS-Co V-2 genome from clinical specimens is limited by their low nucleic acid load and the complexity of the nucleic acid background.To address this issue,we modified and evaluated an approach by utilizing SARS-Co V-2-specific amplicon amplification and Oxford Nanopore Prometh ION platform.This workflow started with the throat swab of the COVID-19 patient,combined reverse transcript PCR,and multi-amplification in one-step to shorten the experiment time,then can quickly and steadily obtain high-quality SARS-Co V-2 genome within 24 h.A comprehensive evaluation of the method was conducted in 42 samples:the sequencing quality of the method was correlated well with the viral load of the samples;high-quality SARS-Co V-2 genome could be obtained stably in the samples with Ct value up to 39.14;data yielding for different Ct values were assessed and the recommended sequencing time was 8 h for samples with Ct value of less than 20;variation analysis indicated that the method can detect the existing and emerging genomic mutations as well;Illumina sequencing verified that ultra-deep sequencing can greatly improve the single read error rate of Nanopore sequencing,making it as low as 0.4/10,000 bp.In summary,high-quality SARS-Co V-2 genome can be acquired by utilizing the amplicon amplification and it is an effective method in accelerating the acquisition of genetic resources and tracking the genome diversity of SARSCo V-2.

ACE2-Targeting antibody suppresses SARS-CoY-2 Omicron and Delta variants

Dear Editor,The pandemic of COVID-19 continues worldwide with many variants arising,especially SARS-CoV-2 Delta(B.1.617.2)and Omicron(B.1.1.529)variants of concern(VOCs).According to WHO,Omicron has spread in almost all the countries with a doubling time less than Delta VOC.

SARS-CoV-2/COVID-19 laboratory biosafety practices and current molecular diagnostic tools

The ongoing severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)/coronavirus disease 2019(COVID-19)pandemic has crippled several countries across the globe posing a serious global public health challenge.Despite the massive rollout of vaccines,molecular diagnosis remains the most important method for timely isolation,diagnosis,and control of COVID-19.Several molecular diagnostic tools have been developed since the beginning of the pandemic with some even gaining emergency use authorization from the United States(US)Food and Drug Administration for in vitro diagnosis of SARS-CoV-2.Herein,we discuss the working principles of some commonly used molecular diagnostic tools for SARS-CoV-2 including nucleic acid amplification tests,isothermal amplification tests,and rapid diagnostic tests.To ensure successful detection while minimizing the risk of cross-infection and misdiagnosis when using these diagnostic tools,laboratories should adhere to proper biosafety practices.Hence,we also present the common biosafety practices that may ensure the successful detection of SARS-CoV-2 from specimens while protecting laboratory workers and non-suspecting individuals from being infected.From this review article,it is clear that the SARS-CoV-2 pandemic has led to an increase in molecular diagnostic tools and the formation of new biosafety protocols that may be important for future and ongoing outbreaks.

Detection, isolation, and characterization of chikungunya viruses associated with the Pakistan outbreak of 2016–2017

The chikungunya virus(CHIKV) is a mosquito-transmitted alphavirus, which has infected millions of people in Africa, Asia, Americas, and Europe since it reemerged in India and Indian Ocean regions in 2005–2006. Starting in the middle of November 2016, CHIKV has been widely spread, and more than 4,000 cases of infections in humans were confirmed in Pakistan. Here, we report the first isolation and characterization of CHIKV from the Pakistan outbreak. Eight CHIKV strains were newly isolated from human serum samples using a cell culture procedure. A full-length genome sequence and eight complete envelope(E1) sequences of CHIKV from Pakistan were obtained in this study. Alignment of the CHIKV E1 sequences revealed that the eight new CHIKV isolates were highly homogeneous, with only two nonsynonymous substitutions found at generally conserved sites(E99 and Q235). Based on the comparison of 342 E1 sequences, the two nonsynonymous mutations were located in well-recognized domains associated with viral functions such as the cell fusion and vector specificity, suggesting their potential functional importance. Phylogenetic analysis indicated that the CHIKV strains from Pakistan originated from CHIKV circulating in the Indian region. This study helps elucidate the epidemics of CHIKV in Pakistan and also provides a foundation for studies of evolution and expansion of CHIKV in South Asia.

Correction to: Rapid Acquisition of High-Quality SARS-CoV-2 Genome via Amplicon-Oxford Nanopore Sequencing

Correction to:Virologica Sinica(2021)36:901-912 https://doi.Org/10.1007/sl 2250-021-00378-8 The original version of article contains errors in Figure 4,Supplementary Figure S2,Supplementary Table S2,and the corresponding description in part 3 of“Results”section.

Strengthening global biosafety capacity The 2nd International Workshop on Biosafety Laboratory Management and Techniques held in Wuhan,China

On 15 October 2018,the 2nd International Workshop on Biosafety Laboratory Management and Techniques was opened in the Wuhan Institute of Virology(WIV),Chinese Academy of Sciences(CAS).A total of 24 scientists and technicians from 22 different countries including Bangladesh,Pakistan,Brazil,Bulgaria,Poland,Cambodia,Cameroon,Croatia.