Human umbilical cord mesenchymal stem cells-derived exosomes attenuate burn-induced acute lung injury via inhibiting ferroptosis.

Our previous study has shown that exosomes derived from human umbilical cord mesenchymal stem cells (hUCMSCs-exo) alleviated burn-induced acute lung injury (ALI). In this study, we explored a novel mechanism by which hUCMSCs-exo contributed to the inhibition of burn-induced ALI. The ALI rat model with severe burn was established for the in vivo experiments, and rats PMVECs were stimulated with the serum from burn-induced ALI rats for the in vitro experiments. The pathological changes of lung tissues were evaluated by HE staining; the cell viability was measured using CCK-8; the iron level and Fe2+ concentration were assessed using Iron Assay Kit and Fe2+ fluorescence detection probe; the mRNA expression of SLC7A11 and GPX4 were measured by qRT-PCR; the protein levels of SLC7A11, GPX4, Nrf2 and HO-1 were detected by western blot. Both the in vivo and in vitro experiments revealed that ferroptosis was significantly induced in burn-induced ALI, which as verified by increased iron level and Fe2+ concentration, and decreased SLC7A11 and GPX4 mRNA and protein levels. Furthermore, both hUCMSCs-exo and Fer-1 (the inhibitor of ferroptosis) alleviated lung inflammation and up-regulated protein levels of Nrf2 and HO-1 in the lung tissues of burn-induced ALI rats. These results suggested that hUCMSCs-exo exhibited a protective role against burn-induced ALI by inhibiting ferroptosis, partly owing to the activation of Nrf2/HO-1 pathway, thus providing a novel therapeutic strategy for burn-induced ALI.

Pseudogene CSPG4P12 inhibits colorectal cancer progression by attenuating epithelial-mesenchymal transition.

Colorectal cancer is one of the most common malignant cancers. Pseudogenes have been identified as oncogenes or tumor suppressor genes in the development of various cancers. However, the function of pseudogene CSPG4P12 in colorectal cancer remains unclear. Therefore, the aim of this study was to investigate the potential role of CSPG4P12 in colorectal cancer and explore the possible underlying mechanism. The difference of CSPG4P12 expression between colorectal cancer tissues and adjacent normal tissues was analyzed using the online Gene Expression Profiling Interactive Analysis 2 (GEPIA2) database. Cell viability and colony formation assays were conducted to evaluate cell viability. Transwell and wound healing assays were performed to assess cell migration and invasion capacities. Western blot was used to measure the expression levels of epithelial-mesenchymal transition-related proteins. Colorectal cancer tissues had lower CSPG4P12 expression than adjacent normal tissues. The overexpression of CSPG4P12 inhibited cell proliferation, invasion, and migration in colorectal cancer cells. Overexpressed CSPG4P12 promoted the expression of E-cadherin, whereas it inhibited the expression of vimentin, N-cadherin, and MMP9. These findings suggested that CSPG4P12 inhibits colorectal cancer development and may serve as a new potential target for colorectal cancer.

Seasonal human coronavirus NL63 epidemics in children in Guilin, China, reveal the emergence of a new subgenotype of HCoV-NL63.

Introduction: Seasonal human coronavirus NL63 (HCoV-NL63) is a frequently encountered virus linked to mild upper respiratory infections. However, its potential to cause more severe or widespread disease remains an area of concern. This study aimed to investigate a rare localized epidemic of HCoV-NL63-induced respiratory infections among pediatric patients in Guilin, China, and to understand the viral subtype distribution and genetic characteristics. Methods: In this study, 83 pediatric patients hospitalized with acute respiratory infections and positive for HCoV-NL63 were enrolled. Molecular analysis was conducted to identify the viral subgenotypes and to assess genetic variations in the receptor-binding domain of the spiking protein. Results: Among the 83 HCoV-NL63-positive children, three subgenotypes were identified: C4, C3, and B. Notably, 21 cases exhibited a previously unreported subtype, C4. Analysis of the C4 subtype revealed a unique amino acid mutation (I507L) in the receptor-binding domain of the spiking protein, which was also observed in the previously reported C3 genotype. This mutation may suggest potential increases in viral transmissibility and pathogenicity. Discussion: The findings of this study highlight the rapid mutation dynamics of HCoV-NL63 and its potential for increased virulence and epidemic transmission. The presence of a unique mutation in the C4 subtype, shared with the C3 genotype, raises concerns about the virus's evolving nature and its potential public health implications. This research contributes valuable insights into the understanding of HCoV-NL63's epidemiology and pathogenesis, which is crucial for effective disease prevention and control strategies. Future studies are needed to further investigate the biological significance of the observed mutation and its potential impact on the virus's transmissibility and pathogenicity.

Spatial and diel variations of bacterioplankton and pico-nanoeukaryote communities and potential biotic interactions during macroalgal blooms.

We investigated spatial heterogeneity and diel variations in bacterioplankton and pico-nanoeukaryote communities, and potential biotic interactions at the extinction stage of the Ulva prolifera bloom in the Jiaozhou Bay, Yellow Sea. It was found that the presence of Ulva canopies significantly promoted the cell abundance of heterotrophic bacteria, raised evenness, and altered the community structure of bacterioplankton. A diel pattern was solely significant for pico-nanoeukaryote community structure. >50 % of variation in the heterotrophic bacterial abundance was accounted for by the ratio of Bacteroidota to Firmicutes, and dissolved organic nitrogen effectively explained the variations in cell abundances of phytoplankton populations. The factors representing biotic interactions frequently contributed substantially more than environmental factors in explaining the variations in diversity and community structure of both bacterioplankton and pico-nanoeukaryotes. There were higher proportions of eukaryotic pathogens compared to other marine systems, suggesting a higher ecological risk associated with the Ulva blooms.

Pseudogene CSPG4P12 inhibits colorectal cancer progression by attenuating epithelial-mesenchymal transition

Colorectal cancer is one of the most common malignant cancers. Pseudogenes have been identified as oncogenes or tumor suppressor genes in the development of various cancers. However, the function of pseudogene CSPG4P12 in colorectal cancer remains unclear. Therefore, the aim of this study was to investigate the potential role of CSPG4P12 in colorectal cancer and explore the possible underlying mechanism. The difference of CSPG4P12 expression between colorectal cancer tissues and adjacent normal tissues was analyzed using the online Gene Expression Profiling Interactive Analysis 2 (GEPIA2) database. Cell viability and colony formation assays were conducted to evaluate cell viability. Transwell and wound healing assays were performed to assess cell migration and invasion capacities. Western blot was used to measure the expression levels of epithelial-mesenchymal transition-related proteins. Colorectal cancer tissues had lower CSPG4P12 expression than adjacent normal tissues. The overexpression of CSPG4P12 inhibited cell proliferation, invasion, and migration in colorectal cancer cells. Overexpressed CSPG4P12 promoted the expression of E-cadherin, whereas it inhibited the expression of vimentin, N-cadherin, and MMP9. These findings suggested that CSPG4P12 inhibits colorectal cancer development and may serve as a new potential target for colorectal cancer.

Characteristics of innate, humoral and cellular immunity in children with non-severe SARS-CoV-2 infection.

The symptoms of children infected with SARS-CoV-2 are mainly asymptomatic, mild, moderate, and a few severe cases. To understand the immune response characteristics of children infected with SARS-COV-2 who do not develop severe cases, 82 children infected with the SARS-CoV-2 delta strain were recruited in this study. Our results showed that high levels of IgG, IgM, and neutralization antibodies appeared in children infected with SARS-CoV-2. SARS-CoV-2 induced upregulation of both pro-inflammatory factors including TNF-α and anti-inflammatory factors including IL-4 and IL-13 in the children, even IL-10. The expression of INF-α in infected children also showed a significant increase compared to healthy children. However, IL-6, one of the important inflammatory factors, did not show an increase in infected children. It is worth noting that a large number of chemokines reduced in the SARS-CoV-2-infected children. Subsequently, TCR Repertoire, TCRß bias, and preferential usage were analyzed on data of TCR next-generation sequencing from 8 SARS-CoV-2-infected children and 8 healthy controls. We found a significant decrease in TCR clonal diversity and a significant increase in TCR clonal expansion in SARS-CoV-2-infected children compared to healthy children. The most frequent V and J genes in SARS-CoV-2 children were TRBV28 and TRBJ2-1. The most frequently VßJ gene pairing in SARS-CoV-2 infected children was TRBV20-1-TRBJ2-1. The strong antiviral antibody levels, low expression of key pro-inflammatory factors, significant elevation of anti-inflammatory factors, and downregulation of many chemokines jointly determine that SARS-CoV-2-infected children rarely develop severe cases. Overall, our findings shed a light on the immune response of non-severe children infected with SARS-CoV-2.

Influence of COVID-19 pandemic on the virus spectrum in children with respiratory infection in Xuzhou, China: a long-term active surveillance study from 2015 to 2021.

BACKGROUND: To investigate the impact of the coronavirus disease 2019 (COVID-19) outbreak on the prevalence of respiratory viruses among pediatric patients with acute respiratory infections in Xuzhou from 2015-2021. METHODS: Severe acute respiratory infection (SARI) cases in hospitalized children were collected from 2015-2021 in Xuzhou, China. Influenza virus(IFV), respiratory syncytial virus (RSV), human parainfluenza virus type 3(hPIV-3), human rhinovirus (hRV), human adenovirus(hAdV), human coronavirus(hCoV) were detected by real-time fluorescence polymerase chain reaction(RT-qPCR), and the results were statistically analyzed by SPSS 23.0 software. RESULTS: A total of 1663 samples with SARI were collected from 2015-2021, with a male-to-female ratio of 1.67:1 and a total virus detection rate of 38.5% (641/1663). The total detection rate of respiratory viruses decreased from 46.2% (2015-2019) to 36% (2020-2021) under the control measures for COVID-19 (P < 0.01). The three viruses with the highest detection rates changed from hRV, RSV, and hPIV-3 to hRV, RSV, and hCoV. The epidemic trend of hPIV-3 and hAdV was upside down before and after control measures(P < 0.01); however, the epidemic trend of RV and RSV had not changed from 2015 to 2021(P > 0.05). After the control measures, the detection rate of hPIV-3 decreased in all age groups, and the detection rate of hCoV increased in all except the 1 ~ 3 years old group. CONCLUSIONS: Implementing control measures for COVID-19 outbreak curbed the spread of respiratory viruses among children as a whole. However, the epidemic of RV and RSV was not affected by the COVID-19 control policy.

Inhibitor of CD147 Suppresses T Cell Activation and Recruitment in CVB3-Induced Acute Viral Myocarditis.

Viral myocarditis (VMC) is a common disease characterized by cardiac inflammation. AC-73, an inhibitor of CD147, disrupts the dimerization of CD147, which participates in the regulation of inflammation. To explore whether AC-73 could alleviate cardiac inflammation induced by CVB3, mice were injected intraperitoneally with AC-73 on the fourth day post-infection (dpi) and sacrificed on the seventh dpi. Pathological changes in the myocardium, T cell activation or differentiation, and expression of cytokines were analyzed using H&E staining, flow cytometry, fluorescence staining and multiplex immunoassay. The results showed that AC-73 alleviated cardiac pathological injury and downregulated the percentage of CD45+CD3+ T cells in the CVB3-infected mice. The administration of AC-73 reduced the percentage of activated CD4+ and CD8+ T cells (CD69+ and/or CD38+) in the spleen, while the percentage of CD4+ T cell subsets in the spleen was not changed in the CVB3-infected mice. In addition, the infiltration of activated T cells (CD69+) and macrophages (F4/80+) in the myocardium also decreased after the AC-73 treatment. The results also showed that AC-73 inhibited the release of many cytokines and chemokines in the plasma of the CVB3-infected mice. In conclusion, AC-73 mitigated CVB3-induced myocarditis by inhibiting the activation of T cells and the recruitment of immune cells to the heart. Thus, CD147 may be a therapeutic target for virus-induced cardiac inflammation.

Discovery of the First Raptor (Regulatory-Associated Protein of mTOR) Inhibitor as a New Type of Antiadipogenic Agent.

Raptor, a regulatory-associated protein of mTOR, has been genetically proved to be an important regulator in lipogenesis. However, its druggable potential is rarely investigated, largely due to the lack of an inhibitor. In this study, the antiadipogenic screening of a daphnane diterpenoid library followed by target fishing led to the identification of a Raptor inhibitor, 1c (5/7/6 carbon ring with orthoester and chlorine functionalities). Pharmacodynamic studies verified that 1c is a potent and tolerable antiadipogenic agent in vitro and in vivo. Mechanistic studies revealed that the targeting of Raptor by 1c could block the formation of mTORC1 and then downregulate the downstream S6K1- and 4E-BP1-mediated C/EBPs/PPARγ signaling, eventually retarding adipocyte cell differentiation at the early stage. These findings suggest that Raptor can be explored as a novel therapeutic target for obesity and its related complications, and 1c as the first Raptor inhibitor may provide a new therapeutic option for these conditions.

Diversity Analysis of Tick-Borne Viruses from Hedgehogs and Hares in Qingdao, China.

Tick-borne viruses (TBVs) have attracted increasingly global public health attention. In this study, the viral compositions of five tick species, Haemaphysalis flava, Rhipicephalus sanguineus, Dermacentor sinicus, Haemaphysalis longicornis, and Haemaphysalis campanulata, from hedgehogs and hares in Qingdao, China, were profiled via metagenomic sequencing. Thirty-six strains of 10 RNA viruses belonging to 4 viral families, including 3 viruses of Iflaviridae, 4 viruses of Phenuiviridae, 2 viruses of Nairoviridae, and 1 virus of Chuviridae, were identified in five tick species. Three novel viruses of two families, namely, Qingdao tick iflavirus (QDTIFV) of the family of Iflaviridae and Qingdao tick phlebovirus (QDTPV) and Qingdao tick uukuvirus (QDTUV) of the family of Phenuiviridae, were found in this study. This study shows that ticks from hares and hedgehogs in Qingdao harbored diverse viruses, including some that can cause emerging infectious diseases, such as Dabie bandavirus. Phylogenetic analysis revealed that these tick-borne viruses were genetically related to viral strains isolated previously in Japan. These findings shed new light on the cross-sea transmission of tick-borne viruses between China and Japan. IMPORTANCE Thirty-six strains of 10 RNA viruses belonging to 4 viral families, including 3 viruses of Iflaviridae, 4 viruses of Phenuiviridae, 2 viruses of Nairoviridae, and 1 virus of Chuviridae, were identified from five tick species in Qingdao, China. A diversity of tick-borne viruses from hares and hedgehogs in Qingdao was found in this study. Phylogenetic analysis showed that most of these TBVs were genetically related to Japanese strains. These findings indicate the possibility of the cross-sea transmission of TBVs between China and Japan.

Effect of Electroacupuncture Added to Pelvic Floor Muscle Training in Women with Stress Urinary Incontinence: A Randomized Clinical Trial.

BACKGROUND: Pelvic floor muscle training (PFMT) is a first-line conservative therapy for stress urinary incontinence (SUI). Electroacupuncture (EA) has been used to treat SUI recently. OBJECTIVE: To compare the effectiveness of PFMT + EA versus PFMT + sham EA for SUI in women. DESIGN, SETTING, AND PARTICIPANTS: A prospective, multicenter, randomized, controlled clinical trial was conducted at four hospitals in China involving 304 women with SUI from May 20, 2014 to November 21, 2017. Data were analyzed from April 20 to December 21, 2018. INTERVENTION: Participants were randomized to receive 8 wk of PFMT+ EA (n = 154) or PFMT + sham EA (n = 150). OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: The primary outcome was the change in the amount of urine leakage measured on a 1-hr pad test. Student's t test, the χ2 test, and the Wilcoxon rank-sum test were used for data analysis. RESULTS AND LIMITATIONS: Among the 304 participants randomized, 286 completed the study. The mean age was 57.6 yr (standard deviation [SD] 8.9) for the PFMT + sham EA group and 57.2 yr (SD 9.1) for the PFMT + EA group. The mean urine leakage at baseline was 13.6 g for the PFMT + sham EA group and 13.9 g for the PFMT + EA group. After the 8-wk intervention, the PFMT + EA group had a greater decrease in mean urine leakage (-9.8 g) than the PFMT + sham EA group (-5.8 g) with a mean difference of 4.0 g (95% confidence interval [CI] 0.8-7.2). Significantly more patients experienced a ≥50% reduction in urine leakage and the mean number of incontinence episodes in 24 h in the PFMT + EA group than in the PFMT + sham EA group (26.3%, 95%CI 15.8-36.8%). The PFMT + EA group experienced better improvement in participant-reported SUI severity at 6 wk (p < 0.001) and 8 wk (p < 0.001) and self-evaluated therapeutic effects at 2-32 wk (p < 0.001) after the intervention. Lack of measurement of the amount of urine leakage during follow-up is a limitation. CONCLUSIONS: In this randomized clinical trial, 8-wk combined treatment with PFMT + EA led to a greater improvement in SUI symptoms and better outcomes than with PFMT + sham EA. PATIENT SUMMARY: We evaluated the effectiveness and safety of pelvic floor muscle training combined with electroacupuncture for stress urinary incontinence in women, Our results show that this is a promising therapeutic approach for the treatment of stress urinary incontinence.

The Viral Load of Human Cytomegalovirus Infection in Children following Hematopoietic Stem Cell Transplant by Chip Digital PCR.

Objective: To detect viral load in human cytomegalovirus (HCMV) infection children after hematopoietic stem cell transplant (HSCT) by chip digital PCR (cdPCR). Methods: The plasmid pUC57-UL83 containing the HCMV-UL83 gene and HCMV AD169 strain were used to evaluate the sensitivity of cdPCR. Either HSV-1, HSV-2, VZV, EBV, HHV-6, or HHV-7 was used to evaluate the specificity of HCMV cdPCR. The cdPCR was compared with quantitative PCR (qPCR) by detecting HCMV infection in 125 children's whole blood samples following HSCT. Results: The limit of detection (LOD) of HCMV cdPCR was 103 copies/ml and the qPCR LOD was 297 copies/ml for plasmid pUC57-UL83. The result of HCMV cdPCR was 146 copies/ml for the HCMV AD169 strain, indicating that the sensitivity of cdPCR was higher than that of qPCR. There is no cross-reaction between HCMV cdPCR and other herpes viruses. The incidence of HCMV infection was 30.40% in 125 children following HSCT by cdPCR. The range of the HCMV viral load was from 107 copies/ml to 6600 copies/ml by cdPCR. Conclusions: cdPCR is more sensitive than qPCR for detecting HCMV viral load. Furthermore, the cdPCR could be used to detect the viral load of HCMV infection before or after HSCT in children.

DNA Holliday Junction: History, Regulation and Bioactivity.

DNA Holliday junction (HJ) is a four-way stranded DNA intermediate that formed in replication fork regression, homology-dependent repair and mitosis, performing a significant role in genomic stability. Failure to remove HJ can induce an acceptable replication fork stalling and DNA damage in normal cells, leading to a serious chromosomal aberration and even cell death in HJ nuclease-deficient tumor cells. Thus, HJ is becoming an attractive target in cancer therapy. However, the development of HJ-targeting ligand faces great challenges because of flexile cavities on the center of HJs. This review introduces the discovery history of HJ, elucidates the formation and dissociation procedures of HJ in corresponding bio-events, emphasizes the importance of prompt HJ-removing in genome stability, and summarizes recent advances in HJ-based ligand discovery. Our review indicate that target HJ is a promising approach in oncotherapy.

Identification of an IRES within the coding region of the structural protein of human rhinovirus 16.

As an alternative mechanism for cap-dependent (m7GpppN) translation, internal ribosome entry site (IRES)-dependent translation has been observed in the 5' untranslated regions (5' UTR) and coding regions of a number of viral and eukaryotic mRNAs. In this study, a series of 5' terminal truncated structural protein genes that were fused with GFP was used to screen for potential IRESs, and IRESs were identified using a bicistronic luciferase vector or GFP expression vector possessing a hairpin structure. Our results revealed that a putative IRES was located between nt 1982 and 2281 in the VP3 coding region of the human rhinovirus 16 (HRV16) genomes. We also demonstrated that effective IRES-initiated protein expression in vitro did not occur through splicing sites or cryptic promoters. We confirmed that thapsigargin (TG), an inducer of endoplasmic reticulum stress (ERS), facilitated increased IRES activity in a dose-dependent manner. Additionally, the secondary structure of the IRES was predicted online using the RNAfold web server.

The genetic and epigenetic regulation of CD55 and its pathway analysis in colon cancer.

Background: CD55 plays an important role in the development of colon cancer. This study aims to evaluate the expression of CD55 in colon cancer and discover how it is regulated by transcriptional factors and miRNA. Methods: The expression of CD55 was explored by TIMER2.0, UALCAN, and Human Protein Atlas (HPA) databases. TRANSFAC and Contra v3 were used to predict the potential binding sites of transcription factors in the CD55 promoter. TargetScan and starBase v2.0 were used to predict the potential binding ability of miRNAs to the 3' untranslated region (3'UTR) of CD55. SurvivalMeth was used to explore the differentially methylated sites in the CD55 promoter. Western blotting was used to detect the expression of TFCP2 and CD55. Dual-luciferase reporter assay and chromatin immunoprecipitation (ChIP) assay were performed to determine the targeting relationship of TFCP2, NF-κB, or miR-27a-3p with CD55. CD55-related genes were explored by constructing a protein-protein interaction (PPI) network and performing pathway analysis by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG). Results: CD55 was highly expressed in colon cancer tissues. The mRNA and protein expression levels of TFCP2 were reduced by si-TFCP2. NF-κB mRNA was obviously reduced by NF-κB inhibitor and increased by NF-κB activator. CD55 protein was also inhibited by miR-27a-3p. Dual-luciferase reporter assays showed that after knocking down TFCP2 or inhibiting NF-κB, the promoter activity of CD55 was decreased by 21% and 70%, respectively; after activating NF-κB, the promoter activity of CD55 increased by 2.3 times. As TFCP2 or NF-κB binding site was mutated, the transcriptional activity of CD55 was significantly decreased. ChIP assay showed that TFCP2 and NF-κB combined to the promoter of CD55. The luciferase activity of CD55 3'UTR decreased after being co-transfected with miR-27a-3p mimics and increased by miR-27a-3p antagomir. As the miR-27a-3p binding site was mutated, we did not find any significant effect of miR-27a-3p on reporter activity. PPI network assay revealed a set of CD55-related genes, which included CFP, CFB, C4A, and C4B. GO and KEGG analyses revealed that the target genes occur more frequently in immune-related pathways. Conclusion: Our results indicated that CD55 is regulated by TFCP2, NF-κB, miR-27a-3p, and several immune-related genes, which in turn affects colon cancer.

Identification of cryptic putative IRESs within the ORF encoding the nonstructural proteins of the human rhinovirus 16 genome.

Internal ribosome entry site (IRES)-dependent translation is a mechanism distinct from 5' cap-dependent translation. IRES elements are located mainly in the 5' untranslated regions (UTRs) of viral and eukaryotic mRNAs. However, IRESs are also found in the coding regions of some viral and eukaryotic genomes to initiate the translation of some functional truncated isoforms. Here, five putative IRES elements of human rhinovirus 16 (HRV16) were identified in the coding region of the nonstructural proteins P2 and P3 through fusion with green fluorescent protein (GFP) expression vectors and bicistronic vectors with a hairpin structure. These five putative IRESs were located at nucleotide positions 4286-4585, 5002-5126, 6245-6394, 6619-6718, and 6629-6778 in the HRV16 genome. The functionality of the five IRESs was confirmed by their ability to initiate GFP expression in vitro. This suggests that an alternative mechanism might be used to increase the efficiency of replication of HRV16.

Genotype and mutation patterns of macrolide resistance genes of Mycoplasma pneumoniae from children with pneumonia in Qingdao, China, in 2019.

OBJECTIVES: This study assessed the incidence and resistance of Mycoplasma pneumoniae (MP) in children in Qingdao, China, in 2019. METHODS: We detected MP infection in 78 pharyngeal swabs from children with pneumonia by qPCR. The RepMP4 element in the P1 adhesin gene, domain V of the 23S rRNA gene, and the L4/L22 ribosomal proteins were amplified by nested PCR. Evolutionary analysis was conducted based on the P1 gene sequence. Resistance mutations in domain V of the 23S rRNA gene and L4/L22 ribosomal proteins were analysed. RESULTS: The incidence of MP infection in children with pneumonia was 59.0% (46/78). The mean duration of MP infection was longer than that of non-MP infection. According to P1 gene sequencing of 21 samples, 12 (57.1%) were type 1 and 9 (42.9%) were type 2. Drug resistance mutations A2063G in domain V of 23S rRNA gene and T508C in L22 were identified from all sequenced MP. However, mutations at positions 2064 and 2617 were not found in this study. C162A mutation appeared in most type 2 samples. A430G mutation appeared in one type 1 sample and in several type 2 samples. T279C mutation in L22 was mostly found in type 2 samples. CONCLUSION: The incidence of MP infection was 59.0% in children with pneumonia in Qingdao in 2019. Type 1 MP infection was slightly more common than type 2, indicating that the genotype of MP is gradually shifting from type 1 to type 2. Macrolide resistance mutation A2063G could be detected in all sequenced MP.

Long Distance Transmission of SARS-CoV-2 from Contaminated Cold Chain Products to Humans - Qingdao City, Shandong Province, China, September 2020.

What is already known about this topic? Though coronavirus disease 2019 (COVID-19) has largely been controlled in China, several outbreaks of COVID-19 have occurred from importation of cases or of suspected virus-contaminated products. Though several outbreaks have been traced to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) isolated on the outer packaging of cold chain products, live virus has not been obtained. What is added by this report? In September 2020, two dock workers were detected as having asymptomatic SARS-CoV-2 infection using throat swabs during routine screening in Qingdao, China. Epidemiological information showed that the two dock workers were infected after contact with contaminated outer packaging, which was confirmed by genomic sequencing. Compared to the Wuhan reference strain, the sequences from the dock workers and the package materials differed by 12-14 nucleotides. Furthermore, infectious virus from the cold chain products was isolated by cell culture, and typical SARS-CoV-2 particles were observed under electron microscopy. What are the implications for public health practice? The international community should pay close attention to SARS-CoV-2 transmission mode through cold chain, build international cooperative efforts in response, share relevant data, and call on all countries to take effective prevention and control measures to prevent virus contamination in cold-chain food production, marine fishing and processing, transportation, and other operations.

VE-822, a novel DNA Holliday junction stabilizer, inhibits homologous recombination repair and triggers DNA damage response in osteogenic sarcomas.

Homologous recombination repair (HRR) is crucial for genomic stability of cancer cells and is an attractive target in cancer therapy. Holliday junction (HJ) is a four-way DNA intermediate that performs an essential role in homology-directed repair. However, few studies about regulatory mechanisms of HJs have been reported. In this study, to better understand the biological effects of HJs, VE-822 was identified as an effective DNA HJ stabilizer to promote the assembly of HJs both in vitro and in cells. This compound could inhibit the HRR level, activate DNA-PKCS to trigger DNA damage response (DDR) and induce telomeric DNA damage via stabilizing DNA HJs. Furthermore, VE-822 was demonstrated to sensitize the osteosarcoma cells to doxorubicin (Dox) by enhancing DNA damage and cellular apoptosis. This work thus reports one novel HJ stabilizer, and provide a potential anticancer strategy through the modulation of DNA HJs.