Global profiling of ribosomal protein acetylation reveals essentiality of acetylation homeostasis in maintaining ribosome assembly and function.

Acetylation is a global post-translational modification that regulates various cellular processes. Bacterial acetylomic studies have revealed extensive acetylation of ribosomal proteins. However, the role of acetylation in regulating ribosome function remains poorly understood. In this study, we systematically profiled ribosomal protein acetylation and identified a total of 289 acetylated lysine residues in 52 ribosomal proteins (r-proteins) from Salmonella Typhimurium. The majority of acetylated lysine residues of r-proteins were found to be regulated by both acetyltransferase Pat and metabolic intermediate acetyl phosphate. Our results show that acetylation plays a critical role in the assembly of the mature 70S ribosome complex by modulating r-proteins binding to rRNA. Moreover, appropriate acetylation is important for the interactions between elongation factors and polysomes, as well as regulating ribosome translation efficiency and fidelity. Dysregulation of acetylation could alter bacterial sensitivity to ribosome-targeting antibiotics. Collectively, our data suggest that the acetylation homeostasis of ribosomes is crucial for their assembly and function. Furthermore, this mechanism may represent a universal response to environmental signals across different cell types.

A novel glycine-rich peptide from Zophobas atratus, coleoptericin B, targets bacterial membrane and protects against Klebsiella pneumoniae-induced mastitis in mice.

OBJECTIVES: The growing occurrence of bacterial resistance has spawned the development of novel antimicrobial agents. Antimicrobial peptides, a class of small molecules with antimicrobial activity, have been regarded as the ideal alternatives to antibiotics. METHODS: In this study, we amplified a new type of Zophobas atratus coleoptericin (denoted coleoptericin B) through rapid amplification of cDNA ends (RACE) PCR and expressed recombinant Z. atratus coleoptericin B (rZA-col B) by prokaryotic expression. Subsequently, we evaluated the antimicrobial effect and biocompatibility of rZA-col B in vivo, investigated its antimicrobial mechanism, and assessed its therapeutic effect in a murine model of mastitis caused by MDR Klebsiella pneumoniae. RESULTS: The in vivo studies demonstrated that rZA-col B possesses broad-spectrum antimicrobial activity against both Gram-positive and Gram-negative bacteria. It exhibited less than 1.5% haemolysis and 10% cytotoxicity, even at a concentration of 128 µM. Additionally, rZA-col B had a minimal risk of inducing drug resistance. Furthermore, rZA-col B could disrupt the integrity of bacterial membranes, induce membrane permeabilization and ultimately lead to bacterial death. Importantly, rZA-col B also alleviated mastitis caused by MDR K. pneumoniae in a murine model by enhancing bacterial clearance, reducing neutrophil infiltration, decreasing TNF-α and IL-1ß expression, and protecting the mammary barrier. CONCLUSIONS: rZA-col B may be a promising antibacterial agent to combat MDR bacterial infection.

Linoleic acid: a natural feed compound against porcine epidemic diarrhea disease.

IMPORTANCE: Porcine epidemic diarrhea virus (PEDV) is a pig coronavirus that causes severe diarrhea and high mortality in piglets, but as no effective drugs are available, this virus threatens the pig industry. Here, we found that the intestinal contents of specific pathogen-free pigs effectively blocked PEDV invasion. Through proteomic and metabolic analyses of the intestinal contents, we screened 10 metabolites to investigate their function and found that linoleic acid (LA) significantly inhibited PEDV replication. Further investigations revealed that LA inhibited viral replication and release mainly by binding with PEDV NSP5 to regulate the PI3K pathway and, in particular, inhibiting AKT phosphorylation. In vivo experiments illustrated that orally administered LA protected pigs from PEDV challenge and severe diarrhea. These findings provide strong support for exploring antiviral drugs for coronavirus treatment.

Identification of a novel LFNG variant in a Chinese fetus with spondylocostal dysostosis and a systematic review.

Spondylocostal dysostosis (SCDO) encompasses a group of skeletal disorders characterized by multiple segmentation defects in the vertebrae and ribs. SCDO has a complex genetic etiology. This study aimed to analyze and identify pathogenic variants in a fetus with SCDO. Copy number variant sequencing and whole exome sequencing were performed on a Chinese fetus with SCDO, followed by bioinformatics analyses, in vitro functional assays and a systematic review on the reported SCDO cases with LFNG pathogenic variants. Ultrasound examinations in utero exhibited that the fetus had vertebral malformation, scoliosis and tethered cord, but rib malformation was not evident. We found a novel homozygous variant (c.1078 C > T, p.R360C) within the last exon of LFNG. The variant was predicted to cause loss of function of LFNG by in silico prediction tools, which was confirmed by an in vitro assay of LFNG enzyme activity. The systematic review listed a total of 20 variants of LFNG in SCDO. The mutational spectrum spans across all exons of LFNG except the last one. This study reported the first Chinese case of LFNG-related SCDO, revealing the prenatal phenotypes and expanding the mutational spectrum of the disorder.

TGF-ß1 reduces the differentiation of porcine IgA-producing plasma cells by inducing IgM+ B cells apoptosis via Bax/Bcl2-Caspase3 pathway.

Transforming growth factor ß1 (TGF-ß1) performs a critical role in maintaining homeostasis of intestinal mucosa regulation and controls the survival, proliferation, and differentiation of many immune cells. In this study, we discovered that the infection of porcine epidemic diarrhea virus (PEDV), a coronavirus, upregulated TGF-ß1 expression via activating Tregs. Besides, recombinant porcine TGF-ß1 decreased the percentage of CD21+ B cells within the lymphocyte population in vitro. We further found that TGF-ß1 reduced the IgA-secreting B cell numbers and also inhibited plasma cell differentiation. Additional investigations revealed that TGF-ß1 induced the apoptosis of IgM+ B cells in both peyer's patches (PPs) and peripheral blood (PB) through the activation of the Bax/Bcl2-Caspase3 pathway. Conversely, the application of the TGF-ß1 signaling inhibitor SB431542 significantly antagonized the TGF-ß1-induced reduction of IgA secretion and B cell apoptosis and restored plasma cell differentiation. Collectively, TGF-ß1 plays an important role in regulating the survival and differentiation of porcine IgA-secreting B cells through the classical mitochondrial apoptosis pathway. These findings will facilitate future mucosal vaccine designs that target the regulation of TGF-ß1 for the control of enteric pathogens in the pig industry.

Ribosome footprint profiling enables elucidating the systemic regulation of fatty acid accumulation in Acer truncatum.

BACKGROUND: The accumulation of fatty acids in plants covers a wide range of functions in plant physiology and thereby affects adaptations and characteristics of species. As the famous woody oilseed crop, Acer truncatum accumulates unsaturated fatty acids and could serve as the model to understand the regulation and trait formation in oil-accumulation crops. Here, we performed Ribosome footprint profiling combing with a multi-omics strategy towards vital time points during seed development, and finally constructed systematic profiling from transcription to proteomes. Additionally, we characterized the small open reading frames (ORFs) and revealed that the translational efficiencies of focused genes were highly influenced by their sequence features. RESULTS: The comprehensive multi-omics analysis of lipid metabolism was conducted in A. truncatum. We applied the Ribo-seq and RNA-seq techniques, and the analyses of transcriptional and translational profiles of seeds collected at 85 and 115 DAF were compared. Key members of biosynthesis-related structural genes (LACS, FAD2, FAD3, and KCS) were characterized fully. More meaningfully, the regulators (MYB, ABI, bZIP, and Dof) were identified and revealed to affect lipid biosynthesis via post-translational regulations. The translational features results showed that translation efficiency tended to be lower for the genes with a translated uORF than for the genes with a non-translated uORF. They provide new insights into the global mechanisms underlying the developmental regulation of lipid metabolism. CONCLUSIONS: We performed Ribosome footprint profiling combing with a multi-omics strategy in A. truncatum seed development, which provides an example of the use of Ribosome footprint profiling in deciphering the complex regulation network and will be useful for elucidating the metabolism of A. truncatum seed oil and the regulatory mechanisms.

Recruitment of C4b-binding protein is not a complement evasion strategy employed by Staphylococcus aureus.

Complement offers a first line of defence against infection through the opsonization of microbial pathogens, recruitment of professional phagocytes to the infection site and the coordination of inflammatory responses required for the resolution of infection. Staphylococcus aureus is a successful pathogen that has developed multiple mechanisms to thwart host immune responses. Understanding the precise strategies employed by S. aureus to bypass host immunity will be paramount for the development of vaccines and or immunotherapies designed to prevent or limit infection. To gain a better insight into the specific immune evasion mechanisms used by S. aureus we examined the pathogen's interaction with the soluble complement inhibitor, C4b-binding protein (C4BP). Previous studies indicated that S. aureus recruits C4BP using a specific cell-wall-anchored surface protein and that bound C4BP limits complement deposition on the staphylococcal surface. Using flow-cytometric-based bacterial-protein binding assays we observed no interaction between S. aureus and C4BP. Moreover, we offer a precautionary warning that C4BP isolated from plasma can be co-purified with minute quantities of human IgG, which can distort binding analysis between S. aureus and human-derived proteins. Combined our data indicates that recruitment of C4BP is not a complement evasion strategy employed by S. aureus.

Limited protection of pneumococcal vaccines against emergent Streptococcus pneumoniae serotype 14/ST876 strains.

PURPOSE: Streptococcus pneumoniae (Spn) is a major cause of child death. We investigated the epidemiology of S. pneumoniae in a pediatric fever clinic and explored the genomics basis of the limited vaccine response of serotype 14 strains worldwide. METHODS: Febrile disease and pneumonia were diagnosed following criteria from the WHO at the end of 2019 at a tertiary children's hospital. Spn was isolated by culture from nasopharyngeal (NP) swabs. The density was determined by lytA-base qPCR. Isolates were serotyped by Quellung and underwent antimicrobial susceptibility testing. Whole-genome sequencing was employed for molecular serotyping, MLST, antibiotic gene determination, SNP calling, recombination prediction, and phylogenetic analysis. RESULTS: The presence of pneumococcus in the nasopharynx (87.5%, 7/8, p = 0.0227) and a high carriage (100%, 7/7, p = 0.0123) were significantly associated with pneumonia development. Living with siblings (73.7%, 14/19, p = 0.0125) and non-vaccination (56.0%, 28/50, p = 0.0377) contributed significantly to the Spn carriage. Serotype 14 was the most prevalent strain (16.67%, 5/30). The genome analysis of 1497 serotype 14 strains indicated S14/ST876 strains were only prevalent in China, presented limited vaccine responses with higher recombination activities within its cps locus, and unique variation patterns in the genes wzg and lrp. CONCLUSION: With the lifting of the one-child policy, it will be crucial for families with multiple children to get PCV vaccinations in China. Due to the highly variant cps locus and distinctive variation patterns in capsule shedding and binding proteins genes, the prevalent S14/ST876 strains have shown poor response to current vaccines. It is necessary to continue monitoring the molecular epidemiology of this vaccine escape clone.

ZIF-67 on Sulfur-Functionalized Graphene Oxide for Lithium-Sulfur Batteries.

How to overcome the problem of fast capacity fading and low sulfur utilization is the key to promote the practical applications of lithium-sulfur (Li-S) batteries. Based on the fact that sulfur-functionalized graphene oxide (GO-S) can avoid the loss of sulfur/polysulfides through the strong C-S interaction, and the zeolitic imidazolate framework (ZIF-67) can capture sulfur and catalyze lithium polysulfide (Li2Sx, 4 ≤ x ≤ 8), the combination of ZIF-S (ZIF-67 after combining with sulfur) with GO-S can be expected to be an excellent electrode material for Li-S batteries due to the synergistic effect. Herein, ZIF-S@GO-S (n) nanocomposites (n = 1, 2, and 3 for the mass ratio of ZIF-67/GO of 4:1, 6:1, and 8:1, respectively) as the cathode materials in Li-S batteries were successfully fabricated, and ZIF-S@GO-S (2) showed better electrochemical performances and cycle stability with a high specific capacity of 1529.5 mA h g-1 at the initial cycle and 792 mA h g-1 after 500 cycles at 0.1 C (1 C = 1675 mA h g-1). The fact that ZIF-S@GO-S (n) can simultaneously improve the conductivity and utilization of S (C-S···S8 and C-S···SxLi2) and the conversion kinetics of Li2Sx (4 ≤ x ≤ 8) provides a new avenue for designing and fabricating promising cathodes for high-performance Li-S batteries.

Effects of subcutaneous immunotherapy in allergic rhinitis children sensitive to dust mites.

BACKGROUND: Subcutaneous immunotherapy (SCIT) is now the only treatment that can modify the natural course of allergic rhinitis (AR). However, not all children with AR benefit from SCIT. OBJECTIVE: To evaluate the efficacy of SCIT in dust-mites-induced AR children and explore correlative factors predicting treatment response to SCIT. METHODS: 225 children aged 4-17 years old with AR were recruited from January 2016 to September 2019, and monitored at baseline, 4, 12, and 24 months after the start of SCIT treatment. The visual-analogue-score (VAS) was used to assess the clinical symptoms. Multivariate binary logistic regression analyses and receiver operating characteristic curves were used to explore correlative factors in predicting the efficacy of SCIT. RESULTS: The significant declines in VAS started after 4 months of SCIT and continued to improve throughout the study compared with baseline. An increase in children's age (OR=0.688, 95%CI: 0.479-0.988) and those with allergic history (OR=0.097, 95%CI: 0.009-1.095) were negatively associated with the risk of poor efficacy. Polysensitized children were more likely to suffer poor efficacy (OR=15.511 95%CI: 1.319-182.355). The clinical response at month 4 (r=0.707) and month 12 (r=0.925) was related to that at month 24. The area under the curve (AUC) for improvement at month 4 and month 12 was 0.746 and 0.860, respectively. CONCLUSION: Our study confirmed the clinical efficacy of SCIT in AR children. Children with younger age, negative allergic history, and multiple allergens may predict a worse efficacy. The onset of action and the clinical response to SCIT in the second year can be predicted as early as by month 4.

Effect of peroxiredoxin 1 on the regulation of trophoblast function by affecting autophagy and oxidative stress in preeclampsia.

PURPOSE: PE is a pregnancy-specific syndrome and one of the main causes of maternal, fetal, and neonatal mortality. PRDX1 is an antioxidant that regulates cell proliferation, differentiation, and apoptosis. The aim of this study is to investigate the effect of PRDX1 on the regulation of trophoblast function by affecting autophagy and oxidative stress in preeclampsia. METHODS: Western blotting, RT-qPCR, and immunofluorescence were used to examine the expression of PRDX1 in placentas. PRDX1-siRNA was transfected to knockdown PRDX1 in HTR-8/SVneo cells. The biological function of HTR-8/SVneo cells was detected by wound healing, invasion, tube formation, CCK-8, EdU, flow cytometry, and TUNEL assays. Western blotting was used to detect the protein expression of cleaved-Caspase3, Bax, LC3II, Beclin1, PTEN, and p-AKT. DCFH-DA staining was used to detect ROS levels by flow cytometry. RESULTS: PRDX1 was significantly decreased in placental trophoblasts in PE patients. Following the exposure of HTR-8/SVneo cells to H2O2, PRDX1 expression was significantly decreased, LC3II and Beclin1 expression was notably increased, and ROS level was also markedly increased. PRDX1 knockdown impaired migration, invasion, and tube-formation abilities and promoted apoptosis, which was accompanied by an increased expression of cleaved-Caspase3 and Bax. PRDX1 knockdown induced a significant decrease in LC3II and Beclin1 expression, along with an elevated p-AKT expression and a decreased PTEN expression. PRDX1 knockdown increased intracellular ROS levels, and NAC attenuated PRDX1 knockdown-induced apoptosis. CONCLUSION: PRDX1 regulated trophoblast function through the PTEN/AKT signaling pathway to affect cell autophagy and ROS level, which provided a potential target for the treatment of PE.

Effect of prosocial behavior on school bullying victimization among children and adolescents: Peer and student-teacher relationships as mediators.

INTRODUCTION: In this study, we examined the relationship between prosocial behavior and school bullying victimization in children and adolescents. We also tested the mediating effects of peer alienation and student-teacher closeness, as well as the moderating effect of the educational stage. METHODS: In total, 538 children and adolescents were recruited from three suburban schools in Beijing, China (252 boys, 286 girls; mean age = 12.47; 237 elementary school students, 101 middle school students, and 200 high school students). The participants were asked to complete the measures of prosocial behavior, peer alienation, and student-teacher closeness at the initial time point and reported school bullying victimization 3 months later. RESULTS: We found that prosocial behavior was directly and negatively associated with traditional bullying victimization (i.e., physical, nonphysical, and relational); however, it had no direct association with cyberbullying victimization. Prosocial behavior was indirectly associated with school bullying victimization (except in the relational dimension) via peer alienation, but no indirect effect of student-teacher closeness was found. Besides, the associations between prosocial behavior, peer alienation, student-teacher closeness, and bullying victimization were found equally among elementary, middle, and high school students. CONCLUSIONS: The findings suggest that prosocial behavior is an important factor associated with decreased school bullying victimization, and peer relationships play a mediating role in this association. Our study extends the current understanding of prosocial behavior primarily as a consequence of child and adolescent development to an antecedent (of school bullying victimization), which contributes to a more comprehensive view of prosocial behavior.

The effect of occlusal disharmony on a chronic stress-induced animal model of gut microbiota dysbiosis.

BACKGROUND AND OBJECTIVES: Chronic stress (CS) is closely related to intestinal health. Occlusal disharmony (OD) is a risk factor for hypersensitivity to novel stress, and the relationship between OD and the intestinal system with or without other chronic stresses remains unclear. Therefore, the purpose of this study was to investigate whether OD affects the gut microbiota and the intestinal barrier in a CS-exposed animal model. METHODS: OD was induced by making a 0.5-mm-thick incision on the right maxillary molar. CS involved exposure to one stressor per day for 35 days. Sprague-Dawley rats were randomly divided into an untreated control group and OD-, CS- and OD + CS-treated groups. The behavioural tests, serum corticosterone level, gut microbiota composition and tight junction protein expression in colon tissue were measured on the 56th day to elucidate the effect of OD on animals under CS. RESULTS: Significant differences in performance on behavioural tests and serum corticosterone concentrations were observed on day 56 in the OD + CS group compared with the control group. Exposure to occlusal disharmony or chronic stress resulted in a change in the composition of the gut microbiota of rats. Differences in the expression of the tight junction proteins zonula occludens-1 and junctional adhesion molecule-A were observed in colon tissue from the OD + CS group compared with the control group. CONCLUSIONS: We concluded that the significant changes in performance on behavioural tests, serum corticosterone concentrations and microbiota dysbiosis and tight junction protein levels induced by OD with CS may indicate that OD is a potential factor promoting gut microbiota dysbiosis.

Vibronic and Cationic Features of 2-Fluorobenzonitrile and 3-Fluorobenzonitrile Studied by REMPI and MATI Spectroscopy and Franck-Condon Simulations.

Fluorinated organic compounds have superior physicochemical properties than general organic compounds due to the strong C-F single bond; they are widely used in medicine, biology, pesticides, and materials science. In order to gain a deeper understanding of the physicochemical properties of fluorinated organic compounds, fluorinated aromatic compounds have been investigated by various spectroscopic techniques. 2-fluorobenzonitrile and 3-fluorobenzonitrile are important fine chemical intermediates and their excited state S1 and cationic ground state D0 vibrational features remain unknown. In this paper, we used two-color resonance two photon ionization (2-color REMPI) and mass analyzed threshold ionization (MATI) spectroscopy to study S1 and D0 state vibrational features of 2-fluorobenzonitrile and 3-fluorobenzonitrile. The precise excitation energy (band origin) and adiabatic ionization energy were determined to be 36,028 ± 2 cm-1 and 78,650 ± 5 cm-1 for 2-fluorobenzonitrile and 35,989 ± 2 cm-1 and 78,873 ± 5 cm-1 for 3-fluorobenzonitrile, respectively. The density functional theory (DFT) at the levels of RB3LYP/aug-cc-pvtz, TD-B3LYP/aug-cc-pvtz, and UB3LYP/aug-cc-pvtz were used to calculate the stable structures and vibrational frequencies for the ground state S0, excited state S1, and cationic ground state D0, respectively. Franck-Condon spectral simulations for transitions of S1 ← S0 and D0 ← S1 were performed based on the above DFT calculations. The theoretical and experimental results were in good agreement. The observed vibrational features in S1 and D0 states were assigned according to the simulated spectra and the comparison with structurally similar molecules. Several experimental findings and molecular features were discussed in detail.

Effect of economic inequality on generosity: A social norm perspective.

Economic inequality has been found to reduce individuals' generosity in western contexts. However, whether this effect is cross-culturally consistent and its internal mechanism remain unclear, as well as how to mitigate this impact. Hence, we explored whether and why economic inequality may erode generosity in a sample of Chinese adults from the social norm perspective and introduced the equal allocation norm to mitigate this effect. Four online studies were conducted: two were correlational (Study 1: n = 300; Study 2: n = 568) and two were experimental (Study 3: n = 289; Study 4: n = 500). Results showed that economic inequality predicted less generosity in the dictator game, and perceived unequal allocation norm accounted for this effect. Moreover, introducing the equal allocation norm could buffer this negative effect. Findings suggest economic inequality impairs generosity, and making the equal allocation norm more salient may guide people to act more generously.

Altruistic behaviour decreases agent's unhealthy food intake: Based on the self-determination theory model of vitality.

This study explored whether altruistic behaviour would decrease agent's unhealthy food intake, and whether vitality and state self-control would sequentially mediate this effect based on the Self-Determination Theory Model of Vitality. It included 1019 college students in total across three studies. Study 1 was a laboratory experiment. By framing a physical task as a helping behaviour or a neutral experimental task, we examined whether these framed tasks impacted participants' subsequent unhealthy food intake levels. Study 2 was an online investigation measuring the relationship between donation (vs. no donation) behaviour and participant's estimated unhealthy food intake level. Study 3 was an online experiment with a mediation test. By random assignment of conducting a donation behaviour versus a neutral task, we examined whether these behaviours affected participants' vitality, state self-control, and estimated unhealthy food intake levels. In addition, we tested a sequential mediation model with vitality and state self-control as the mediators. Both unhealthy and healthy foods were included in Study 2 and 3. Results showed that altruistic behaviour could decrease agent's unhealthy (but not healthy) food intake, and this effect was sequentially mediated by vitality and state self-control. The findings highlight that altruistic acts may buffer agents against unhealthy eating behaviour.

Assembly and comparative analysis of the first complete mitochondrial genome of Acer truncatum Bunge: a woody oil-tree species producing nervonic acid.

BACKGROUND: Acer truncatum (purpleblow maple) is a woody tree species that produces seeds with high levels of valuable fatty acids (especially nervonic acid). The species is admired as a landscape plant with high developmental prospects and scientific research value. The A. truncatum chloroplast genome has recently been reported; however, the mitochondrial genome (mitogenome) is still unexplored. RESULTS: We characterized the A. truncatum mitogenome, which was assembled using reads from PacBio and Illumina sequencing platforms, performed a comparative analysis against different species of Acer. The circular mitogenome of A. truncatum has a length of 791,052 bp, with a base composition of 27.11% A, 27.21% T, 22.79% G, and 22.89% C. The A. truncatum mitogenome contains 62 genes, including 35 protein-coding genes, 23 tRNA genes and 4 rRNA genes. We also examined codon usage, sequence repeats, RNA editing and selective pressure in the A. truncatum mitogenome. To determine the evolutionary and taxonomic status of A. truncatum, we conducted a phylogenetic analysis based on the mitogenomes of A. truncatum and 25 other taxa. In addition, the gene migration from chloroplast and nuclear genomes to the mitogenome were analyzed. Finally, we developed a novel NAD1 intron indel marker for distinguishing several Acer species. CONCLUSIONS: In this study, we assembled and annotated the mitogenome of A. truncatum, a woody oil-tree species producing nervonic acid. The results of our analyses provide comprehensive information on the A. truncatum mitogenome, which would facilitate evolutionary research and molecular barcoding in Acer.

Genomic characterization and pathogenicity analysis of a porcine deltacoronavirus strain isolated in western China.

Porcine deltacoronavirus (PDCoV) is an enteric virus that was first identified in 2012. Although PDCoV has been detected worldwide, there is little information about its circulation in western China. In this study, fecal samples were collected from piglets with watery diarrhea in western China between 2015 and 2018 for the detection of PDCoV. The positive rate was 29.9%. A PDCoV strain (CHN/CQ/BN23/2016, BN23) was isolated and selected for further investigation. Phylogenetic analysis showed that this strain formed an individual cluster between the early Chinese lineage and the Chinese lineage. RDP4 and SimPlot analysis demonstrated that strain BN23 is a recombinant of Thailand/S5015L/2015 and CHN-AH-2004. The pathogenicity of BN23 was evaluated in 3-day-old piglets. Challenged piglets developed serious clinical signs and died at 3 days post-inoculation. Our data show that PDCoV is prevalent in western China and that strain BN23 is highly pathogenic to newborn piglets. Therefore, more attention should be paid to emerging PDCoV strains in western China.

Evaluation of RT-qPCR Primer-Probe Sets to Inform Public Health Interventions Based on COVID-19 Sewage Tests.

Sewage surveillance is increasingly employed as a supplementary tool for COVID-19 control. Experiences learnt from large-scale trials could guide better interpretation of the sewage data for public health interventions. Here, we compared the performance of seven commonly used primer-probe sets in RT-qPCR and evaluated the usefulness in the sewage surveillance program in Hong Kong. All selected primer-probe sets reliably detected SARS-CoV-2 in pure water at 7 copies per µL. Sewage matrix did not influence RT-qPCR determination of SARS-CoV-2 concentrated from a small-volume sewage (30 mL) but introduced inhibitory impacts on a large-volume sewage (920 mL) with a ΔCt of 0.2-10.8. Diagnostic performance evaluation in finding COVID-19 cases showed that N1 was the best single primer-probe set, while the ORF1ab set is not recommended. Sewage surveillance using the N1 set for over 3200 samples effectively caught the outbreak trend and, importantly, had a 56% sensitivity and a 96% specificity in uncovering the signal sources from new cases and/or convalescent patients in the community. Our study paves the way for selecting detection primer-probe sets in wider applications in responding to the COVID-19 pandemic.

Preparation and identification of monoclonal antibodies against porcine CD103.

Dendritic cells (DCs) play an important role in activating, regulating, and maintaining the immune response. CD103+ DCs, one of the DC subpopulations, mainly function in the mucosal immune response. They are responsible for capturing and carrying antigens to the relevant lymph nodes to activate the downstream immune responses. However, there is limited available information regarding the function of CD103+ DCs in the porcine mucosal immune response. In this study, two monoclonal antibodies (mAbs) against porcine CD103 were prepared, and their applications were evaluated by enzyme-linked immunosorbent assay (ELISA), indirect immunofluorescence assay (IFA), and flow cytometry. The produced mAbs (7F3 and 9H3) were both IgG1 subtype with κ chains in the light chain. The 7F3 recognizes a linear epitope (PDLRPRAQVYFSDLE) while 9H3 recognizes another linear epitope (QILDEGQVLLGAVGA). The prepared mAbs could be used in vivo to detect the cells expressing CD103 molecules, giving wide applications of both mAbs. In conclusion, this study successfully prepared 2 mAbs against CD103 protein, and they showed applicability in vivo experiments, which will provide the basis for the study of porcine mucosal immunity. KEY POINTS: • Preparation of monoclonal antibodies against porcine CD103 molecule • Analysis of the distribution of CD103 protein on different cells is possible • Exploration of the CD103+ DCs function in porcine mucosal immunity is possible.