Background COVID-19 is a novel and highly virulent virus, which caused a rapid and massive onset of clinical trials in a short period of time.With the aim to obtain suggestions in the guidance on performing public health emergency clinical trials, and control this virus in China and other countries and for the prevention of the onset of other infectious viruses in the future. Methods COVID-19, SARS, MERS and Ebola clinical trials registered in the Chinese clinical trial registry and clinical trials.gov were collected and analyzed and intervention protocols were descriptively analyzed, focusing on the analysis and comparison of the drug used. The search period ended on February 24, 2020. Results The number of the registered COVID-19 clinical trials was 295. Among 203 intervention trials, 78.3% (159) were drug clinical trials. The 159 COVID-19 trials were designed and analyzed with the highest proportion of random, open control study [66.0% (105)], and blind randomized trials [13.8% (22)]. The drug mostly used was Lopinavir/Ritonavir (15.1%). The sample size median 100,IQR(interquartile range) 140. The number of the registered SARS was 6, MERS 15, and Ebola 97. Among 3 MERS and 19 Ebola drug intervention clinical trials, MERS and Ebola were randomized, blind, and placebo-controlled drug clinical trials accounting for 100% (3) and 31.6% (6), respectively, while SARS were vaccine trials, without drug intervention clinical trials registered. Conclusions Some of the COVID-19 clinical trials and drug selection performed are somewhat disordered, requiring greater attention to the needs, science assumptions, ethics and quality management of the clinical research. Thus, during the epidemic period, the country should deliver guidance on how to perform appropriate emergency clinical trials, design a scientifically based clinical trial program and focus on researching drugs or vaccines that have great potential.

HIV-1 deleted for the vif accessory gene encapsidates the cellular cytidine deaminase APOBEC3G. Upon infection, the encapsidated APOBEC3G induces G-->A mutations in the viral reverse transcripts. The G-->A mutations result either from C-->U deamination of the minus strand or deamination of both strands followed by repair of the plus strand. We report here that minus-strand deamination occurred over the length of the virus genome, preferentially at CCCA sequences, with a graded frequency in the 5'-->3' direction. APOBEC3G induced previously undetected C-->T mutations in the 5' U3 and the primer-binding site, both of which become transiently single-stranded during reverse transcription. In vitro, APOBEC3G bound and deaminated single-stranded DNA (ssDNA) but not double-stranded DNA (dsDNA) or DNA-RNA hybrids. We propose that the requirement for ssDNA accounts for the minus-strand mutations, the 5'-->3' graded frequency of deamination and the rare C-->T mutations.

BackgroundDaptomycin remains one of our last-line anti-staphylococcal agents. This study aims to characterize the genetic evolution to daptomycin resistance in S. aureus.MethodsWhole genome sequencing was performed on a unique collection of isogenic, clinical (21 strains) and laboratory (12 strains) derived strains that had been exposed to daptomycin and developed daptomycin-nonsusceptibility. Electron microscopy (EM) and lipid membrane studies were performed on selected isolates.ResultsOn average, six coding region mutations were observed across the genome in the clinical daptomycin exposed strains, whereas only two mutations on average were seen in the laboratory exposed pairs. All daptomycin-nonsusceptible strains had a mutation in a phospholipid biosynthesis gene. This included mutations in the previously described mprF gene, but also in other phospholipid biosynthesis genes, including cardiolipin synthase (cls2) and CDP-diacylglycerol-glycerol-3-phosphate 3-phosphatidyltransferase (pgsA). EM and lipid membrane composition analyses on two clinical pairs showed that the daptomycin-nonsusceptible strains had a thicker cell wall and an increase in membrane lysyl-phosphatidylglycerol.ConclusionPoint mutations in genes coding for membrane phospholipids are associated with the development of reduced susceptibility to daptomycin in S. aureus. Mutations in cls2 and pgsA appear to be new genetic mechanisms affecting daptomycin susceptibility in S. aureus.

Rapid rebound of plasma viremia in patients after interruption of long-term combination antiretroviral therapy (cART) suggests persistence of low-level replicating cells or rapid reactivation of latently infected cells. To further characterize rebounding virus, we performed extensive longitudinal clonal evolutionary studies of HIV env C2-V3-C3 regions and exploited the temporal relationships of rebounding plasma viruses with regard to pretreatment sequences in 20 chronically HIV-1-infected patients having undergone multiple 2-week structured treatment interruptions (STI). Rebounding virus during the short STI was homogeneous, suggesting mono-or oligoclonal origin during reactivation. No evidence for a temporal structure of rebounding virus in regard to pretreatment sequences was found. Furthermore, expansion of distinct lineages at different STI cycles emerged. Together, these findings imply stochastic reactivation of different clones from long-lived latently infected cells rather than expansion of viral populations replicating at low levels. After treatment was stopped, diversity increased steadily, but pretreatment diversity was, on average, achieved only >2.5 years after the start of STI when marked divergence from preexisting quasispecies also emerged. In summary, our results argue against persistence of ongoing lowlevel replication in patients on suppressive cART. Furthermore, a prolonged delay in restoration of pretreatment viral diversity after treatment interruption demonstrates a surprisingly sustained evolutionary bottleneck induced by punctuated antiretroviral therapy.HIV-1 ͉ latent reservoir ͉ structured treatment interruption ͉ viral diversity ͉ coreceptor usage