Improving Non-Line-of-Sight Identification in Cellular Positioning Systems Using a Deep Autoencoding and Generative Adversarial Network Model.

Positioning service is a critical technology that bridges the physical world with digital information, significantly enhancing efficiency and convenience in life and work. The evolution of 5G technology has proven that positioning services are integral components of current and future cellular networks. However, positioning accuracy is hindered by non-line-of-sight (NLoS) propagation, which severely affects the measurements of angles and delays. In this study, we introduced a deep autoencoding channel transform-generative adversarial network model that utilizes line-of-sight (LoS) samples as a singular category training set to fully extract the latent features of LoS, ultimately employing a discriminator as an NLoS identifier. We validated the proposed model in 5G indoor and indoor factory (dense clutter, low base station) scenarios by assessing its generalization capability across different scenarios. The results indicate that, compared to the state-of-the-art method, the proposed model markedly diminished the utilization of device resources and achieved a 2.15% higher area under the curve while reducing computing time by 12.6%. This approach holds promise for deployment in future positioning terminals to achieve superior localization precision, catering to commercial and industrial Internet of Things applications.

Biological and immunological characterization of major capsid protein VP1 from distinct GII.2 norovirus clusters.

Human noroviruses (HuNoVs) are a leading cause of acute viral gastroenteritis worldwide. Infectious outbreaks due to recombinant NoV genotype called GII.P16-GII.2 have been frequently reported since 2016. In this study, we expressed the major capsid protein VP1 from three GII.2 NoV strains using the recombinant baculovirus expression system. The assembly, histo-blood group antigen (HBGA)-binding patterns, and cross-blocking abilities of VP1 proteins were investigated. All the three NoV VP1 proteins successfully assembled into virus-like particles (VLPs). The HBGA-binding assay demonstrated a temporal binding pattern. The latest isolate bound to saliva samples of all blood types. Sequence alignment suggested that the observed gain in HBGA-binding ability was attributed to a limited number of amino acid mutations. Using chimeric VP1 proteins, we demonstrated that synergistic effects resulted in enhanced binding ability. Bile salts increased GII.2 VLP avidity for HBGAs except GII.2-2011/M1. In vitro blockade assay of salivary HBGA-VLP binding demonstrated the presence of cross-blocking effects among different strains. This study provides insight into the evolutionary binding characteristics and cross-blocking effects of GII.2 NoVs to facilitate the development of measures to control this type of viruses.

GII.6 norovirus major capsid protein VP1 derived from distinct clusters induce cross-blocking effects.

Unlike pandemic GII.4 norovirus, GII.6 norovirus shows limited sequence variation in its major capsid protein VP1. In this study, we investigated the VP1 expression profiles, binding abilities, and cross-blocking effects of three GII.6 norovirus strains derived from three distinct variants. Norovirus VP1 was expressed using a recombinant baculovirus expression system and characterized by transmission electron microscopy, mass spectrometry, salivary histo-blood group antigen (HBGA)-virus like particles (VLPs) binding and binding blockade assays. Mass spectrometry revealed the expected molecular weight (MW) of full-length proteins and degraded or cleaved fragments of all three VP1 proteins. Peptide mapping showed loss of 2 and 3 amino acids from the N- and C-terminus, respectively. Further, the co-expression of VP1 and VP2 proteins did not lead to extra fragmentation during mass spectrometry. Salivary HBGA-VLP binding assay revealed similar binding patterns of the three GII.6 VP1 proteins. Salivary HBGA-VLP binding blockade assay induced cross-blocking effects. Our results demonstrate similar binding abilities against salivary HBGAs and specific cross-blocking effects for GII.6 norovirus strains derived from distinct variants, suggesting that fewer GII.6 strains from different evolutionary variants are needed for the development of norovirus vaccines.

Identification of a norovirus GII-specific antigenic epitope.

Noroviruses (NoVs) are the chief cause of acute viral gastroenteritis worldwide. By employing the major capsid protein VP1 of a GII.6 NoV strain as an immunogen, we generated two monoclonal antibodies (mAbs) with wide-spectrum binding activities against NoV genogroup II (GII) VP1 proteins. One mAb (10G7) could bind to native and denatured GII-specific VP1 proteins. The other mAb (10F2) could bind to all tested native GII VP1 proteins, but not to denatured GII.3, GII.4, GII.7, or GII.17 VP1 proteins. Using GII.6/GII.4 fusion proteins, the mAb 10F2 binding region was confirmed to be located in the C-terminal P1 domain. An enzyme-linked immunosorbent assay based on peptides covering the P domain did not detect any binding. Using a panel of VP1 proteins with swapped regions, deletions, and mutations, the mAb 10F2 binding region was determined to be located between residues 496 and 513. However, the residue(s) responsible for its varied binding affinity for different denatured GII VP1 proteins remain to be identified. In summary, two NoV GII-specific cross-reactive mAbs were generated, and their binding regions were determined. Our results might facilitate the detection and immunogenic study of NoVs.

Characteristics of drug resistance mutations in ART-experienced HIV-1 patients with low-level viremia in Zhengzhou City, China.

Although most people living with HIV (PLWH) receiving antiretroviral therapy (ART) achieve continuous viral suppression, some show detectable HIV RNA as low-level viremia (LLV) (50-999 copies/mL). Drug resistance mutations (DRMs) in PLWH with LLV is of particular concern as which may lead to treatment failure. In this study, we investigated the prevalence of LLV and LLV-associated DRMs in PLWH in Zhengzhou City, China. Of 3616 ART-experienced PLWH in a long-term follow-up cohort from Jan 2022 to Aug 2023, 120 were identified as having LLV. Of these PLWH with LLV, we obtained partial pol and integrase sequences from 104 (70 from HIV-1 RNA and 34 from proviral DNA) individuals. DRMs were identified in 44 individuals. Subtyping analysis indicated that the top three subtypes were B (48.08%, 50/104), CRF07_BC (31.73%, 33/104), and CRF01_AE (15.38%, 16/104). The proportions of nucleoside reverse transcriptase inhibitors (NRTIs), non-nucleoside reverse transcriptase inhibitors (NNRTIs), protease inhibitors (PIs), and integrase strand transfer inhibitors (INSTIs) associated DRMs were 23.83% (24/104), 35.58% (37/104), 5.77% (6/104), and 3.85% (4/104), respectively, which contributed to an overall prevalence of 42.31% (44/104). When analyzed by individual DRMs, the most common mutation(s) were V184 (18.27%, 19/104), followed by V179 (11.54%, 12/104), K103 (9.62%, 10/104), Y181 (9.62%, 10/104), M41 (7.69%, 8/104), and K65R (7.69%, 8/104). The prevalence of DRMs in ART-experienced PLWH with LLV is high in Zhengzhou City and continuous surveillance can facilitate early intervention and provision of effective treatment.

Characterization of cleavage patterns and assembly of N-terminally modified GII.6 norovirus VP1 proteins.

When expressed in vitro, the major capsid protein VP1 of a norovirus (NoV) can self-assemble into virus-like particles (VLPs), and its N-terminus can tolerate foreign sequences without the assembly being affected. We explored the effects of adding an N-terminal sequence to the VP1 of a GII.6 NoV strain on its cleavage and assembly. Sequences of varying lengths derived from the minor capsid protein VP2 were added to the VP1 N-terminus. Using a recombinant baculovirus expression system, the fusion proteins were expressed, and their cleavage patterns and assembly were analyzed using mass spectrometry and transmission electron microscopy, respectively. All of the fusion proteins were successfully expressed and exhibited varying degrees of enzyme cleavage, most probably at the N-terminus. LC-MS results revealed that similar fragments were obtained for wild-type VP1 and fusion proteins, indicating that the cleavage sites were conserved. EM analysis indicated that VLPs of different sizes were successfully assembled for certain fusion proteins. The study data demonstrate that NoV VP1 can tolerate foreign sequences of a certain length at its N-terminus and that a conserved cleavage pattern exists, which might facilitate further investigation of the assembly and cleavage mechanisms of NoV.

Safety and immunogenicity of homologous prime-boost CoronaVac vaccine in people living with HIV in China: A multicenter prospective cohort study.

People living with HIV (PLWH) are particularly vulnerable to SARS-CoV-2. This multicentre prospective cohort study evaluated the long-term immunogenicity and safety of a third homologous dose of Sinovac CoronaVac in PLWH in China. A total of 228 PLWH and 127 HIV-negative controls were finally included and followed up for 6 months. Fewer participants reported mild or moderate adverse reactions, and no serious adverse events were observed. The median levels of neutralizing antibodies (nAbs) and immunoglobulin G against the receptor-binding domain of the spike protein (S-IgG) in PLWH (655.92 IU/mL, IQR: 175.76-1663.55; 206.83 IU/mL, IQR: 85.20-397.82) were comparable to those in control group (1067.16 IU/mL, IQR: 239.85-1670.83; 261.70 IU/mL, IQR: 77.13-400.75), and reached their peak at 4 weeks, exhibiting a delayed peak pattern compared to the 2-week peak in control group. After then, the immune titres gradually decreased over time, but most participants still maintained positive seroconversion at the 6-month mark. Multivariable generalized estimating equation analysis indicated that CD4+T cell count, HIV viral load, and antiretroviral therapy (ART) were independent factors strongly associated with immune response (each p < 0.05). We suggested that PLWH should maintain well-controlled HIV status through ART and receive timely administration of the second booster dose for optimal protection.

Increased prevalence of pretreatment drug resistance mutations in treatment-naïve people living with HIV-1 in Henan Province, China (2022/23).

Human deficiency virus type 1 (HIV-1) harboring drug resistance mutations (DRMs) before the initiation of antiretroviral therapy (ART) poses a serious threat to the efficacy of current ART regimens. Currently, the prevalence of pre-treatment drug resistance mutations (PDRMs) including transmitted DRMs (TDRMs) is not completely clear. Understanding this prevalence better should offer valuable data for clinical- and government-level decision-making. To closely monitor the PDRM trend in treatment-naïve people living with HIV/AIDS (PLWHA) in Henan Province, China, plasma samples from the patients seeking treatments at our hospital from January 2022 to February 2023 were collected for genotypic drug resistance testing. From the 645 patients whose samples were collected, partial pol and integrase gene sequences were obtained from 637 patients. Subtyping analysis indicated that the top-three most common subtypes, in descending order, were CRF07_BC (41.76%, 266/637), CRF01_AE (28.26%, 180/637), and B (20.41%, 130/637). PDRMs were observed in 5.18% (33/637), 6.28% (40/637), 0.31% (2/637), and 2.83% (18/637) cases for nucleoside reverse transcriptase inhibitors (NRTIs), non-nucleoside reverse transcriptase inhibitors (NNRTIs), protease inhibitors (PIs), and integrase strand transfer inhibitors (INSTIs), respectively; all these medications contributed to an overall PDRM prevalence of 11.93% (76/637). On analyzing individual PDRMs, we noted that the most commonly observed mutation(s) were K103S/N (3.77%, 24/637), M184I/V (3.14%, 20/637), followed by K65R (1.26%, 8/637), and V106A/M (1.10%, 7/637). PDRM prevalence in ART-naïve PLWHA of Henan Province is high and increased compared with that noted in previous years. However, evidence of cluster-linked outbreaks of PDRMs is lacking, suggesting that measures such as education about adherence and improved treatment strategies with a low incidence of failure can effectively reduce PDRM prevalence.

Identification of a GII.6 norovirus blockade antibody epitope.

Noroviruses (NoVs) are the leading agent that causes acute viral gastroenteritis worldwide. Sporadic cases of GII.6 NoV have been reported primarily in addition to occasional outbreaks. Using the major capsid protein VP1 of GII.6 NoV derived from three distinct clusters, we demonstrated three blockade monoclonal antibodies (mAbs, 1F7, 1F11, and 2B6) generated previously exhibited cluster-specific binding effects. Combining sequence alignment and blocking immune epitopes, we sequentially designed a total of 18 mutant proteins containing one, two, or three mutations, or swapped regions. Indirect enzyme-linked immunosorbent assay (ELISA) demonstrated that the three blocking mAbs lost or showed significantly reduced binding for H383Y, D387N, V390D, and T391D mutant proteins. Combining data from mutant proteins with swapping regions and point mutations, the binding region of the three mAbs was mapped to residues 380-395. Sequence alignment of this region showed within-cluster conservation and between-cluster variations, further strengthening the idea of blockade epitope-mediated evolution of NoV.

Pattern of infection and genotypes of human papillomavirus in Zhengzhou City based on a four-year (2015-2018) epidemiological study.

Persistent human papillomavirus (HPV) infection has been associated with the development of cervical cancer. To reduce the incidence of cervical cancer and promote awareness of HPV, a government-sponsored epidemiological study was conducted from 2015 to 2018 in Zhengzhou City. A total of 184,092 women aged 25-64 years were included, of which 19,579 were infected with HPV, reflecting a prevalence of 10.64 percent (19,579/184,092). The HPV genotypes found were classified as high-risk (13 genotypes) and low-risk (8 genotypes). Single and multiple infections were detected in 13,787 (70.42 percent) and 5,792 (29.58 percent) women, respectively. The five most common high-risk genotypes detected, listed in descending order, were HPV52 (2.14 percent; 3,931/184,092), HPV16 (2.04 percent; 3,756/184,092), HPV58 (1.42 percent; 2,607/184,092), HPV56 (1.01 percent; 1,858/184,092), and HPV39 (0.81 percent; 1,491/184,092). Meanwhile, the most common low-risk genotype was HPV53 (0.88 percent; 1,625/184,092). The prevalence of HPV gradually increased with age, with the highest occurring in women aged 55-64 years. The prevalence of single-type HPV infection decreased with age, whereas that of multiple-type HPV infection increased with age. This study indicates a high burden of HPV infection in women in Zhengzhou City.

The safety and immunogenicity of a two-dose schedule of CoronaVac, and the immune persistence of vaccination for six months, in people living with HIV: A multicenter prospective cohort study.

Background: People living with HIV (PLWH) are more vulnerable to SARS-CoV-2. However, evidence on the immunogenicity of coronavirus disease 2019 (COVID-19) vaccines in this population is insufficient. The objective of this study is to assess the immunogenicity and safety of the two-dose schedule of Sinovac CoronaVac for 6 months postvaccination in PLWH. Methods: We conducted a multicenter prospective cohort study among PLWH and HIV-negative adults in China. Participants who received two doses of CoronaVac prior to the recruitment were allocated into two groups and followed up for 6 months. The neutralizing antibodies (nAbs), immunoglobulin G against the receptor-binding domain of the spike protein (S-IgG), and gamma-interferon (IFN-γ) were measured to assess the associations among CoronaVac immunogenicity and related factors. Adverse reactions were collected to evaluate the safety profile of vaccination. Results: A total of 203 PLWH and 100 HIV-negative individuals were enrolled. A small portion of participants reported mild or moderate adverse reactions without serious adverse events. Median nAbs level in PLWH (31.96 IU/mL, IQR: 12.34-76.40) was lower than that in the control group (46.52 IU/mL, IQR: 29.08-77.30) at the 2-4 weeks postvaccination (P=0.002), and the same trend was presented for median S-IgG titer (37.09 vs. 60.02 IU/ml) (both P <0.05). The nAbs seroconversion rate in the PLWH group was also lower than in the control group (75.86% vs. 89.00%). After then, the immune responses reduced over time in term of only 23.04% of PLWH and 36.00% of HIV-negative individuals had a positive seroconversion for nAbs at 6-month. The multivariable generalized estimating equation analysis showed that PLWH with CD4+T count≥350 cells/µL presented higher immune response than PLWH with CD4+T count <350 cells/µL in terms of antibody seroconversion and titers. The immunogenicity did not differ in participants with low or high HIV viral load. The S-antigen specific IFN-γ immunity was generally stable and had a slow attenuation in both two groups for 6 months postvaccination. Conclusion: The Sinovac CoronaVac was generally safe and immunogenic in PLWH, but the immunity response was inferior and the antibodies vanished faster compared to HIV-negative individuals. This study suggested a shorter than 6-month interval of prime-boost vaccination for PLWH to ensure a better protection.

Consistency of drug-resistant mutations in plasma and peripheral blood mononuclear cells of patients with treatment-naïve and treatment-experienced HIV-1 infection.

Introduction: Genotypic drug resistance testing is cursrently recommended by the World Health Organization for all patients infected with human immunodeficiency virus type 1 (HIV-1) undergoing care or switching regimes due to failure with previous antiretroviral therapy (ART). Patients with human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS) who meet the criteria for free testing for genotypic drug resistance due to poor adherence in Henan Province may resume their previous regimens before resampling. Therefore, resistance testing based on plasma RNA can fail in a proportion of patients. Resistance testing based on peripheral blood mononuclear cells (PBMCs) is an alternative option. In this study, we investigated the differences in drug-resistant mutations (DRMs) between plasma HIV RNA and proviral DNA in treatment-experienced and treatment-naïve patients. Methods: Matched plasma RNA and proviral DNA samples of 66 HIV-1 infected treatment-naïve and 78 treatment-experienced patients were selected for DRM analysis and comparison. Results: DRMs were detected in 27.3% (18/66) of treatment-naïve and 80.8% (63/78) of treatment-experienced samples. Resistance to at least one drug was detected based on analysis of plasma RNA and proviral DNA in 7.6% (5/66) and 9.1% (6/66) of treatment-naïve patients and in 79.5% (62/78) and 78.2% (61/78) of treatment-experienced patients, respectively. Furthermore, 61/66 (92.4%) of treatment-naïve patients showed concordant RNA and DNA drug resistance. When drug resistance was defined as intermediate and high, the concordance of drug resistance profiles of paired RNA and proviral DNA samples derived from treatment-naïve patients were up to 97.0% compared with only 80.8% (63/78) in treatment-experienced patients. Discussion: Our data indicate that drug resistance testing based on plasma RNA or proviral DNA might be interchangeable in treatment-naïve patients, whereas plasma RNA-based testing remains the best choice for drug resistance analysis in patients with ART failure in clinical practice.

Towards artificial general intelligence via a multimodal foundation model.

The fundamental goal of artificial intelligence (AI) is to mimic the core cognitive activities of human. Despite tremendous success in the AI research, most of existing methods have only single-cognitive ability. To overcome this limitation and take a solid step towards artificial general intelligence (AGI), we develop a foundation model pre-trained with huge multimodal data, which can be quickly adapted for various downstream cognitive tasks. To achieve this goal, we propose to pre-train our foundation model by self-supervised learning with weak semantic correlation data crawled from the Internet and show that promising results can be obtained on a wide range of downstream tasks. Particularly, with the developed model-interpretability tools, we demonstrate that strong imagination ability is now possessed by our foundation model. We believe that our work makes a transformative stride towards AGI, from our common practice of "weak or narrow AI" to that of "strong or generalized AI".

Sequence addition to the N- or C-terminus of the major capsid protein VP1 of norovirus affects its cleavage and assembly into virus-like particles.

Norovirus (NoV) infection is a leading cause of non-bacterial gastroenteritis worldwide and there are currently no effective therapeutics available to target the virus. The norovirus major capsid protein VP1 is a potential candidate for the development of vaccines due to the similar morphology and immunogenicity of its assembled virus-like particles (VLPs) compared to native virions. In this study, we explored the effects of N- and C-terminal sequence additions to the VP1 of a GII.4 NoV during its assembly into VLPs. A series of sequences of different lengths derived from the minor capsid protein VP2 of the GII.4 NoV were added to the N- and C-terminus of VP1. The fusion proteins were expressed using a recombinant baculovirus expression system and the assembly of the expressed fusion proteins was subsequently observed under electron microscopy (EM). Our results indicated that all constructed fusion proteins were successfully expressed with different degrees of enzyme cleavage at the N-terminus. Electron microscopy revealed the successful assembly of VLPs of different sizes for all fusion proteins. An in vitro binding assay for VLP-histo-blood group antigens (HBGAs) indicated that all fusion proteins exhibited similar binding patterns compared with their wild-type VP1. Our results demonstrate that (Xi et al., 1990) [1] NoV VP1 can tolerate foreign sequences at its N- or C-terminus without affecting its ability to assemble into VLPs, and (Jiang et al., 1992) [2] that the cleavage pattern and effects of foreign sequences on the sizes of assembled VLPs observed in this study might represent important experimental data that can be used to elucidate VP1 self-assembly.

Expression of chimeric proteins based on a backbone of the GII.4 norovirus VP1 and their application in the study of a GII.6 norovirus-specific blockade epitope.

The surface-exposed loop regions of the protruding domain of the norovirus (NoV) major capsid protein VP1 can tolerate the insertion of foreign antigens without affecting its assembly into subviral particles. In this study, we investigated the tolerance of the surface-exposed loop region of the GII.4 NoV VP1 by replacing it with homologous or heterologous sequences. We designed a panel of constructs in which the amino acid sequence from position 298-305 of the GII.4 NoV VP1 was replaced by sequences derived from the same region of GI.3, GII.3, GII.6, and GII.17 NoVs as well as neutralizing epitopes of enterovirus type 71 and varicella-zoster virus. The constructs were synthesized and expressed using a recombinant baculovirus expression system. The expression of target proteins was measured by indirect enzyme-linked immunosorbent assay (ELISA), and the assembly of virus-like particles (VLPs) was confirmed by electron microscopy. Our results showed that all of the constructs expressed high levels of target chimeric proteins, and all of the chimeric proteins successfully assembled into VLPs or subviral particles. An in vitro VLP-histo-blood group antigen (HBGA) binding assay revealed that chimeric-protein-containing VLPs did not bind or showed reduced binding to salivary HBGAs, a ligand for NoV particles. The results of an in vitro VLP-HBGA binding blockade assay indicated that the predicted surface-exposed loop region of the GII.6 NoV VP1 may comprise a blockade epitope. In summary, the surface-exposed loop region of the GII.4 NoV VP1 can be replaced by foreign sequences of a certain length. Using this strategy, we found that the predicted surface-exposed loop region of GII.6 NoV VP1 might contain a blockade epitope.

Prevalence of integrase strand transfer inhibitor (INSTIs) resistance mutations in Henan Province, China (2018-2020).

BACKGROUND: Antiretroviral therapy (ART) regimens containing integrase strand transfer inhibitors (INSTIs) have become the recommended treatment for human immunodeficiency virus type 1 (HIV-1)-infected patients in the updated guidelines in China. In this study, we investigated the prevalence of acquired and transmitted INSTI-associated resistance of HIV-1 strains in the Henan Province (China) to provide guidance on the implementation of routine INSTI-associated HIV-1 genotypic resistance testing. METHODS: Serum samples from HIV-1-infected patients seeking treatment in our hospital from August 2018 to December 2020 were collected and the HIV-1 integrase gene coding sequence was amplified, sequenced and analyzed for INSTI resistance. RESULTS: We obtained integrase sequence data from a total of 999 HIV-1-infected patients, including 474 ART-naive patients, 438 ART-treated patients, and 87 patients with unknown treatment history. We detected INSTI resistance in 12 patients (1.2%, 12/999) of the study group, which included 9 ART-treated patients (2.05%, 9/438), with 6 being INSTI-treated (14.63%, 6/41) and 3 INSTI-naive (0.76%, 3/397) and 3 ART-naive (0.63%, 3/474) patients. The most common major resistance mutation was E138AK (0.5%, 5/999), while the most common accessory resistance mutation was E157Q (1.8%, 18/999). Phylogenetic analysis based on the HIV-1 integrase gene indicated that INSTI resistance was primarily detected in patients infected with HIV-1 subtype B. CONCLUSIONS: In conclusion, our study reveals that INSTI resistance is observed in INSTI-treated patients, as expected, and the prevalence of INSTI resistance in ART-naive patients in Henan Province is low. However, baseline INSTI resistance testing should be considered, as the prescription of INSTI-based regimens is anticipated to increase considerably in the near future.

Amino acid substitutions in VP2, VP1, and 2C attenuate a Coxsackievirus A16 in mice.

Coxsackievirus A16 (CVA16) is one of the major etiological agents of hand, foot and mouth disease (HFMD), a common acute infectious disease affecting infants and young children. Severe symptoms of the central nervous system may develop and even lead to death. Here, a plaque-purified CVA16 strain, L731-P1 (P1), was serially passaged in Vero cells for six times and passage 6 (P6) stock became highly attenuated in newborn mice. Genomic sequencing of the P1 and P6 revealed seven nucleotide substitutions at positions 1434 (C to U), 2744 (A to G), 2747 (A to G), 3161 (G to A), 3182 (A to G), 4968 (C to U), and 6064 (C to U). Six of these substitutions resulted in amino acid changes at VP2-T161 M, VP1-N102D, VP1-T103A, VP1-E241K, VP1-T248A, and 2C-S297F, respectively. P1-based infectious cDNA was generated to further investigate these virulent determinants. Independent reverse transcription-polymerase chain reaction (RT-PCR) amplifications for mutant constructions and plaque-purification of the P6 for isolation of variants were performed to determine dominant mutations and strains more related to attenuation. The virulent P1, attenuated P6, as well as a plaque purified strain (PP) and other four recombinant mutants, were inoculated into one-day-old BALB/c mice and the 50% lethal dose of each strain was determined. Comparison of virulence among these strains indicated that amino acid changes of VP1-N102D, VP1-E241K and 2C-S297F might be associated more closely with a high level attenuation of CVA16-L731-P6 than other mutations. Identification of novel residues associated with virulence may contribute to understanding of molecular basis of virulence of CVA16 and other enteroviruses.

Genomic and phylodynamic analysis of sapoviruses isolated in Henan Province, China.

In this study, we determined the near-complete and partial genome sequences of ten SaV isolates. Phylogenetic analysis based on full-length VP1 and RdRp nucleotide sequences indicated that nine isolates were of GI.1 and one was GII.3. Evolutionary dynamics analysis indicated that GI.1 and GII.3 SaVs evolved at different rates, the latter evolving more rapidly. Cluster analysis indicated that distantly related GI.1 SaVs were more similar in their amino acid compositions than were GII.3 SaVs. The data provided in this study may facilitate studies on SaV genomic diversity and epidemiological patterns in China and worldwide.