Nucleic Acid Research Articles

Waste to protein: A systematic review of a century of advancement in microbial fermentation of agro-industrial byproducts.

Increasing global consumption of protein over the last five decades, coupled with concerns about the impact on emissions of animal-based protein production, has created interest in alternative protein sources. Microbial proteins (MPs), derived through the fermentation of agro-industrial byproducts, present a promising option. This review assesses a century of advancements in this domain. We conducted a comprehensive review and meta-analysis, examining 347 relevant research papers to identify trends, technological advancements, and key influencing factors in the production of MP. The analysis covered the types of feedstocks and microbes, fermentation methods, and the implications of nucleic acid content on the food-grade quality of proteins. A conditional inference tree model and Bayesian factor were used to ascertain the impact of various parameters on protein content. Out of all the studied parameters, such as type of feedstock (lignocellulose, free sugars, gases, and others), type of fermentation (solid, liquid, gas), type of microbe (bacteria, fungi, yeast, and mix), and operating parameters (temperature, time, and pH), the type of fermentation and microbe were identified as the largest influences on protein content. Gas and liquid fermentation demonstrated higher protein content, averaging 52% and 42%, respectively. Among microbes, bacterial species produced a higher protein content of 51%. The suitable operating parameters, such as pH, time, and temperature, were also identified for different microbes. The results point to opportunities for continued innovation in feedstock, microbes, and regulatory alignment to fully realize the potential of MP in contributing to global food security and sustainability goals.

Dynamic Covalent Boronate Chemistry Accelerates the Screening of Polymeric Gene Delivery Vectors via In Situ Complexation of Nucleic Acids.

Gene therapy provides exciting new therapeutic opportunities beyond the reach of traditional treatments. Despite the tremendous progress of viral vectors, their high cost, complex manufacturing, and side effects have encouraged the development of nonviral alternatives, including cationic polymers. However, these are less efficient in overcoming cellular barriers, resulting in lower transfection efficiencies. Although the exquisite structural tunability of polymers might be envisaged as a versatile tool for improving transfection, the need to fine-tune several structural parameters represents a bottleneck in current screening technologies. By taking advantage of the fast-forming and strong boronate ester bond, an archetypal example of dynamic covalent chemistry, a highly adaptable gene delivery platform is presented, in which the polycation synthesis and pDNA complexation occur in situ. The robustness of the strategy entitles the simultaneous evaluation of several structural parameters at will, enabling the accelerated screening and adaptive optimization of lead polymeric vectors using dynamic covalent libraries.

Prevalence and trends of Chlamydia trachomatis infection in female sex workers and men who have sex with men in China: a systematic review and meta-analysis

IntroductionChlamydia trachomatis infection can cause a significant disease burden in high-risk populations. This study aimed to assess the overall prevalence of C. trachomatis infection, and determine the long-term trends and geographic distribution of this infection among female sex workers (FSWs) and men who have sex with men (MSM) in China.MethodsThe PubMed, Web of Science, CNKI, Wanfang Data and VIP databases were searched from 1 January 1990 through 30 April 2023. Publications in which C. trachomatis infection was detected using nucleic acid amplification tests (NAATs) were included. The Q test and I2 statistics were used to assess the heterogeneity between studies. A random-effect model was used to estimate the pooled prevalence of C. trachomatis infection. Subgroup, meta-regression, and sensitivity analyses were performed to explore the sources of heterogeneity. Publication bias was evaluated using Egger’s test. Trend analysis of the prevalence was performed using the Jonckheere-Terpstra trend test method.ResultsSixty-one studies were eligible for inclusion (including 38 for FSWs and 23 for MSM). The pooled prevalence of C. trachomatis infection was 19.5% (95% CI: 16.4, 23.0) among FSWs and 12.7% (95% CI: 9.2, 17.7) in the rectum, 6.4% (95% CI: 5.3, 7.8) in the urethra and 1.3% (95% CI: 0.8, 2.1) in the oropharynx from MSM in China. The subgroup analyses showed that the sample size, study period, study region, specimen collection type, molecular diagnosis method, and recruitment site could explain some heterogeneity among studies of FSWs, and the publication language, study period, study region, molecular diagnosis method, and specimen collection anatomical site could explain some heterogeneity among studies of MSM. From 1998 to 2004, 2005 to 2009, 2010 to 2015, and 2016 to 2021, the pooled prevalence of C. trachomatis infection among FSWs were 30.3%, 19.9%, 21.4%, and 11.3%, respectively. For MSM, the pooled prevalence from 2003 to 2009, 2010 to 2015, and 2016 to 2022 were 7.8%, 4.7%, and 6.5%, respectively. However, no overall decline in the prevalence of C. trachomatis infection was observed among FSWs (z = -1.51, P = 0.13) or MSM (z = -0.71, P = 0.48) in China.ConclusionsThe prevalence of C. trachomatis infection was high in these two high-risk populations in China. The findings of this study provide evidence for the formulation of effective surveillance and screening strategies for the prevention and control of C. trachomatis infection among these two specific populations.

Templating Peptide Chemistry with Nucleic Acids: Toward Artificial Ribosomes, Cell-Specific Therapeutics, and Novel Protein-Mimetic Architectures.

In biology, nanomachines like the ribosome use nucleic acid templates to synthesize polymers in a sequence-specific, programmable fashion. Researchers have long been interested in using the programmable properties of nucleic acids to enhance chemical reactions via colocalization of reagents using complementary nucleic acid handles. In this review, we describe progress in using nucleic acid templates, handles, or splints to enhance the covalent coupling of peptides to other peptides or oligonucleotides. We discuss work in several areas: creating ribosome-mimetic systems, synthesizing bioactive peptides on DNA or RNA templates, linking peptides into longer molecules and bioactive antibody mimics, and scaffolding peptides to build protein-mimetic architectures. We close by highlighting the challenges that must be overcome in nucleic acid-templated peptide chemistry in two areas: making full-length, functional proteins from synthetic peptides and creating novel protein-mimetic architectures not possible through macromolecular folding alone.

Multiplexed Detection Strategies for Biosensors Based on the CRISPR-Cas System.

A growing number of applications require simultaneous detection of multiplexed nucleic acid targets in a single reaction, which enables higher information density in combination with reduced assay time and cost. Clustered regularly interspaced short palindromic repeats (CRISPR) and the CRISPR-Cas system have broad applications for the detection of nucleic acids due to their strong specificity, high sensitivity, and excellent programmability. However, realizing multiplexed detection is still challenging for the CRISPR-Cas system due to the nonspecific collateral cleavage activity, limited signal reporting strategies, and possible cross-reactions. In this review, we summarize the principles, strategies, and features of multiplexed detection based on the CRISPR-Cas system and further discuss the challenges and perspective.

Detection of MicroRNA-155 based on lambda exonuclease selective digestion and CRISPR/cas12a-assisted amplification

In numerous malignancies, miRNA-155 is overexpressed and has oncogenic activity because it is one of the most efficient microRNAs for inhibiting apoptosis in human cancer cells. As a result, the highest sensitive detection of the miRNA-155 gene is a technological instrument that can enable early cancer screening. In this study, a miRNA-155 biosensor was created to create a hairpin probe that can bind to the miRNA-155 gene using lambda nucleic acid exonuclease, which can cut the 5′ phosphorylated double strand, and by the DNA probe is recognized by the Cas12a enzyme, which then activates Cas12a to catalyze trans-cutting produces strong fluorescence. Research finding, the target concentration's logarithm and corresponding fluorescence intensity have a strong linear connection, and the limit of detection (LOD) of the sensing system was determined to be 8.3 pM. In addition, the biosensor displayed exceptional specificity, low false-positive signal, and high sensitivity in detecting the miRNA-155 gene in serum samples. This study's creation of a biosensor that has high sensitivity, good selectivity, and is simple to operate provides promising opportunities for research into biosensor design and early cancer detection.

Data-driven regularization lowers the size barrier of cryo-EM structure determination

Macromolecular structure determination by electron cryo-microscopy (cryo-EM) is limited by the alignment of noisy images of individual particles. Because smaller particles have weaker signals, alignment errors impose size limitations on its applicability. Here, we explore how image alignment is improved by the application of deep learning to exploit prior knowledge about biological macromolecular structures that would otherwise be difficult to express mathematically. We train a denoising convolutional neural network on pairs of half-set reconstructions from the electron microscopy data bank (EMDB) and use this denoiser as an alternative to a commonly used smoothness prior. We demonstrate that this approach, which we call Blush regularization, yields better reconstructions than do existing algorithms, in particular for data with low signal-to-noise ratios. The reconstruction of a protein–nucleic acid complex with a molecular weight of 40 kDa, which was previously intractable, illustrates that denoising neural networks will expand the applicability of cryo-EM structure determination for a wide range of biological macromolecules.

IFI207, a young and fast-evolving protein, controls retroviral replication via the STING pathway.

Mammalian AIM-2-like receptor (ALR) proteins bind nucleic acids and initiate production of type I interferons or inflammasome assembly, thereby contributing to host innate immunity. In mice, the Alr locus is highly polymorphic at the sequence and copy number level, and we show here that it is one of the most dynamic regions of the genome. One rapidly evolving gene within this region, Ifi207, was introduced to the Mus genome by gene conversion or an unequal recombination event a few million years ago. Ifi207 has a large, distinctive repeat region that differs in sequence and length among Mus species and even closely related inbred Mus musculus strains. We show that IFI207 controls murine leukemia virus (MLV) infection in vivo and that it plays a role in the STING-mediated response to cGAMP, dsDNA, DMXXA, and MLV. IFI207 binds to STING, and inclusion of its repeat region appears to stabilize STING protein. The Alr locus and Ifi207 provide a clear example of the evolutionary innovation of gene function, possibly as a result of host-pathogen co-evolution.IMPORTANCEThe Red Queen hypothesis predicts that the arms race between pathogens and the host may accelerate evolution of both sides, and therefore causes higher diversity in virulence factors and immune-related proteins, respectively . The Alr gene family in mice has undergone rapid evolution in the last few million years and includes the creation of two novel members, MndaL and Ifi207. Ifi207, in particular, became highly divergent, with significant genetic changes between highly related inbred mice. IFI207 protein acts in the STING pathway and contributes to anti-retroviral resistance via a novel mechanism. The data show that under the pressure of host-pathogen coevolution in a dynamic locus, gene conversion and recombination between gene family members creates new genes with novel and essential functions that play diverse roles in biological processes.

Magneto-fluorescent nanobiosensor with tetrahedral framework nucleic acid-confined aptamer for trace adenosine triphosphate detection

Accurate quantitation of trace-level ATP biomarkers often suffers from interference of sample matrix and remains a challenge. Herein, a novel magnetic biological nanosensor (MBNS) integrating tetrahedral framework nucleic acid (tFNA)-confined aptamers and ultrasensitive laser-induced fluorescence (LIF) was tailored and evaluated. The fluorescent aptamer nanoprobe hybridized with FAM-labelled cDNA was particularly incorporated into the inner cavity of tFNA, enabling a dual-mode mechanism that integrates molecular size selection and aptamer affinity recognition. By this strategy, the benefits of tFNA molecular sieve, the super sensitive properties of LIF, and the specific recognition of "aptamer gene codes" were integrated, as triggered the superior response of ATP. The structures, properties and reaction mechanism of tFNA, as well as tFNA modified with aptamer probe at different sites, were characterized in detail. A high level of anti-interference was achieved, shielding against non-specific adsorption even in matrices with high protein and analogue content, 103~105 times higher than ATP. The release of fluorescent beacon from aptamer probe was facilely driven by specific binding of ATP, and an ultra-sensitive detection of 75 pmol/L ATP was obtained without amplification. It was 2-3 orders of magnitude more sensitive than most fluorescent aptasensors. Applied to serum samples, the stability and reproducibility of the resultant aptasensor have been validated with the intra- and inter-assay RSD in 1.6~6.4% and -1.5~8.4%, respectively. Acceptable recoveries of 96.5~106.8% were achieved, consistent with the LC-MS method. It was expected to open a simple and efficient protocol for highly specific and ultrasensitive ATP detection in clinical diagnostics.

Eukaryotic Initiation Translation Factor 2A activation by cannabidiolic acid alters the protein homeostasis balance in glioblastoma cells

Eukaryotic Initiation Translation Factor 2A (EIF2A) is considered to be primarily responsible for the initiation of translation when a cell is subjected to stressful conditions. However, information regarding this protein is still incomplete. Using a combination of proteomic approaches, we demonstrated that EIF2A is the molecular target of the naturally occurring bioactive compound cannabidiolic acid (CBDA) within human glioblastoma cells. This finding allowed us to undertake a study aimed at obtaining further information on the functions that EIF2A plays in tumor cells. Indeed, our data showed that CBDA is able to activate EIF2A when the cells are in no-stress conditions. It induces conformational changes in the protein structure, thus increasing EIF2A affinity towards the proteins participating in the Eukaryotic Translation Machinery. Consequently, following glioblastoma cells incubation with CBDA we observed an enhanced neosynthesis of proteins involved in the stress response, nucleic acid translation and organization, and protein catabolism. These changes in gene expression resulted in increased levels of ubiquitinated proteins and accumulation of the autophagosome. Our results, in addition to shedding light on the molecular mechanism underlying the biological effect of a phytocannabinoid in cancer cells, demonstrated that EIF2A plays a critical role in regulation of protein homeostasis.

NETosis-Inspired Cell Surface-Constrained Framework Nucleic Acids Traps (FNATs) for Cascaded Extracellular Recognition and Cellular Behavior Modulation.

Upon pathogenic stimulation, activated neutrophils release nuclear DNA into the extracellular environment, forming web-like DNA structures known as neutrophil extracellular traps (NETs), which capture and kill bacteria, fungi, and cancer cells. This phenomenon is commonly referred to as NETosis. Inspired by this, we introduce a cell surface-constrained web-like framework nucleic acids traps (FNATs) with programmable extracellular recognition capability and cellular behavior modulation. This approach facilitates dynamic key chemical signaling molecule recognition such as adenosine triphosphate (ATP), which is elevated in the extracellular microenvironment, and triggers FNA self-assembly. This, in turn, leads to in situ tightly interwoven FNAs formation on the cell surface, thereby inhibiting target cell migration. Furthermore, it activates a photosensitizer-capturing switch, chlorin e6 (Ce6), and induces cell self-destruction. This cascade platform provides new potential tools for visualizing dynamic extracellular activities and manipulating cellular behaviors using programmable in situ self-assembling DNA molecular devices.

NETosis‐Inspired Cell Surface‐Constrained Framework Nucleic Acids Traps (FNATs) for Cascaded Extracellular Recognition and Cellular Behavior Modulation

AbstractUpon pathogenic stimulation, activated neutrophils release nuclear DNA into the extracellular environment, forming web‐like DNA structures known as neutrophil extracellular traps (NETs), which capture and kill bacteria, fungi, and cancer cells. This phenomenon is commonly referred to as NETosis. Inspired by this, we introduce a cell surface‐constrained web‐like framework nucleic acids traps (FNATs) with programmable extracellular recognition capability and cellular behavior modulation. This approach facilitates dynamic key chemical signaling molecule recognition such as adenosine triphosphate (ATP), which is elevated in the extracellular microenvironment, and triggers FNA self‐assembly. This, in turn, leads to in situ tightly interwoven FNAs formation on the cell surface, thereby inhibiting target cell migration. Furthermore, it activates a photosensitizer‐capturing switch, chlorin e6 (Ce6), and induces cell self‐destruction. This cascade platform provides new potential tools for visualizing dynamic extracellular activities and manipulating cellular behaviors using programmable in situ self‐assembling DNA molecular devices.

Importance of Biopolymers in Pharmaceutical and Medical Fields

Biopolymers have gained significant traction in the pharmaceutical and medical fields due to their unique properties and versatile applications. These naturally derived polymers exhibit remarkable characteristics such as biodegradability, biocompatibility, renewability, affordability, and availability. Their role in tissue engineering, wound healing, and biosensor development has been extensively explored. In tissue engineering, biopolymers serve as scaffolds or matrices, supporting cell growth, proliferation, and differentiation for both hard and soft tissue regeneration. Hard tissue scaffolds often incorporate biopolymers like collagen, chitosan, and gelatin, combined with bioactive ceramics like hydroxyapatite, mimicking the natural composition of bone. Soft tissue scaffolds employ biopolymers such as collagen, gelatin, elastin, and alginate, fabricated into hydrogels, fibrous meshes, or porous structures for applications like skin, vascular, cardiac, and nerve tissue regeneration. Biopolymers have demonstrated promising potential in promoting wound healing and tissue repair, creating moist wound dressings, absorbing exudates, and providing a favorable environment for tissue regeneration. Biopolymers like collagen, chitosan, and alginate have been investigated for this purpose. In biosensor development, biopolymers offer biocompatibility and the ability to immobilize biomolecules such as enzymes, antibodies, or nucleic acids, serving as matrices for biological recognition elements while maintaining their activity and stability

Systematic Review and Meta-analysis of the Association Between Mycoplasma Genitalium and Pelvic Inflammatory Disease (PID)

Abstract Background Differences in opinion concerning the contribution of Mycoplasma genitalium to pelvic inflammatory disease (PID) has resulted in inconsistencies across global testing and treatment guidelines. We conducted a systematic review and meta-analysis to determine the association between M. genitalium and PID and M. genitalium positivity within PID cases to provide a contemporary evidence base to inform clinical practice (PROSPERO registration: CRD42022382156). Methods PubMed, Embase, Medline, and Web of Science were searched to 1 December 2023 for studies that assessed women for PID using established clinical criteria and used nucleic acid amplification tests to detect M. genitalium. We calculated summary estimates of the (1) association of M. genitalium with PID (pooled odds ratio [OR]) and 2) proportion of PID cases with M. genitalium detected (pooled M. genitalium positivity in PID), using random-effects meta-analyses, with 95% confidence intervals (CI). Results Nineteen studies were included: 10 estimated M. genitalium association with PID, and 19 estimated M. genitalium positivity in PID. M. genitalium infection was significantly associated with PID (pooled OR = 1.67 [95% CI: 1.24–2.24]). The pooled positivity of M. genitalium in PID was 10.3% [95% CI: 5.63–15.99]. Subgroup and meta-regression analyses showed that M. genitalium positivity in PID was highest in the Americas, in studies conducted in both inpatient and outpatient clinic settings, and in populations at high risk of sexually transmitted infections. Conclusions M. genitalium was associated with a 67% increase in odds of PID and was detected in about 1 of 10 clinical diagnoses of PID. These data support testing women for M. genitalium at initial PID diagnosis.

Development of a highly sensitive ampicillin sensor utilizing functionalized aptamers.

To develop a sensitive and simple ampicillin (AMP) sensor for trace antibiotic residue detection, the influencing factors of the modification effect of nanogold-functionalized nucleic acid sequences (Adenine: A, Thymine: T) were comprehensively analyzed in this study, including the modification method, base length and type. It was found that under the same base concentration, longer chains are more likely to reach saturation than shorter chains; and when the base concentration and length are both the same, A exhibits a higher saturation modification level compared to T. Based on these research findings, a highly sensitive fluorescence aptamer sensor for detecting ampicillin was constructed using the optimized functionalized sequence (ployA6-aptamer) and experimental conditions (6 hours binding time between nucleic acid aptamer and complementary strand, pH 7 working solution, 20 minutes detection time) based on the principle of fluorescence resonance energy transfer. The sensor has a detection range of 0.18 ng ml-1 to 3.11 ng ml-1 for ampicillin, with a detection limit of 0.04 ng ml-1. It exhibits significant selectivity and achieves an average recovery rate of 98.71% in tap water and 91.83% in milk. This method can be used not only for residual ampicillin detection, but also for highly sensitive detection of various antibiotics and small biological molecules by replacing the aptamer type. It provides a research basis for the design of highly sensitive fluorescence aptamer sensors and further applications of nanogold@DNA composite structures.

Twin Scholarships of Glycomedicine and Precision Medicine in Times of Single-Cell Multiomics.

Systems biology and multiomics research expand the prospects of planetary health innovations. In this context, this mini-review unpacks the twin scholarships of glycomedicine and precision medicine in the current era of single-cell multiomics. A significant growth in glycan research has been observed over the past decade, unveiling and establishing co- and post-translational modifications as dynamic indicators of both pathological and physiological conditions. Systems biology technologies have enabled large-scale and high-throughput glycoprofiling and access to data-intensive biological repositories for global research. These advancements have established glycans as a pivotal third code of life, alongside nucleic acids and amino acids. However, challenges persist, particularly in the simultaneous analysis of the glycome and transcriptome in single cells owing to technical limitations. In addition, holistic views of the complex molecular interactions between glycomics and other omics types remain elusive. We underscore and call for a paradigm shift toward the exploration of integrative glycan platforms and analysis methods for single-cell multiomics research and precision medicine biomarker discovery. The integration of multiple datasets from various single-cell omics levels represents a crucial application of systems biology in understanding complex cellular processes and is essential for advancing the twin scholarships of glycomedicine and precision medicine.

Two-layer cascaded catalytic hairpin assemblies based on locked nucleic acids for one-step and highly sensitive ctDNA detection.

Enzyme-free signal amplification of catalytic hairpin assembly (CHA) has enabled sensitive detection of circulating tumor DNA (ctDNA) in early clinical diagnosis. Conventional CHA strategies are restrained by the limited amplification efficiency of the single-stage system, and signal leakage from "breathing" influence and nuclease degradation. Here, we introduced two-layer cascaded locked nucleic acid (LNA)-assisted CHA circuits with the intelligent incorporation of LNA in the hairpins and reporter for the highly sensitive one-step detection of scarce ctDNA. The target-triggered upstream CHA reaction continuously generates hybrid products to catalyze the downstream CHA reaction for transducing the primary sensing event, and the released target and the produced hybrid product trigger the next catalytic reaction round at the same time and finally cascade to amplify the target ctDNA fluorescence output signal. Meanwhile, the stronger binding affinity of the LNA-DNA duplex endows the two-layer LNA-assisted CHA system with thermodynamic stability and nuclease resistance, and thus our designed system exhibits an excellent detection performance for target ctDNA in the range from 2 pM to 5 nM with a low detection limit of 0.6 pM. Significantly, the two-layer LNA-assisted CHA circuits have been successfully implemented for the feasible analysis of clinical samples. This two-layer cascaded LNA-assisted CHA strategy provides a promising high sensitivity tool for one-step detection of scarce ctDNA from complex clinical samples and would facilitate the reconfiguration of DNA circuit-based DNA nanotechnology for the precise analysis of other biomarkers in clinical research fields.

Tetranuclear Polypyridylruthenium(II) Complexes as Selective Nucleic Acid Stains for Flow Cytometric Analysis of Monocytic and Epithelial Lung Carcinoma Large Extracellular Vesicles.

Selective staining of extracellular vesicles (EVs) is a major challenge for diagnostic and therapeutic applications. Herein, the EV labeling properties of a new class of tetranuclear polypyridylruthenium(II) complexes, Rubb7-TNL and Rubb7-TL, as phosphorescent stains are described. These new stains have many advantages over standard stains to detect and characterize EVs, including: high specificity for EV staining versus cell staining; high phosphorescence yields; photostability; and a lack of leaching from EVs until incorporation with target cells. As an example of their utility, large EVs released from control (basal) or lipopolysaccharide (LPS)-stimulated THP-1 monocytic leukemia cells were studied as a model of immune system EVs released during bacterial infection. Key findings from EV staining combined with flow cytometry were as follows: (i) LPS-stimulated THP-1 cells generated significantly larger and more numerous large EVs, as compared with those from unstimulated cells; (ii) EVs retained native EV physical properties after staining; and (iii) the new stains selectively differentiated intact large EVs from artificial liposomes, which are models of cell membrane fragments or other lipid-containing debris, as well as distinguished two distinct subpopulations of monocytic EVs within the same experiment, as a result of biochemical differences between unstimulated and LPS-stimulated monocytes. Comparatively, the staining patterns of A549 epithelial lung carcinoma-derived EVs closely resembled those of THP-1 cell line-derived EVs, which highlighted similarities in their selective staining despite their distinct cellular origins. This is consistent with the hypothesis that these new phosphorescent stains target RNA within the EVs.

Analysis of epidemiological characteristics of respiratory pathogens in children with influenza-like illnesses in a children's hospital in Beijing from 2022 to 2023

To investigate the status and epidemiological characteristics of respiratory pathogens infections in children with influenza-like illnesses (ILI) in Beijing Children's Hospital from 2022 to 2023. A dual amplification technique was used to detect nucleic acids of seven common respiratory pathogens, including influenza A virus (Flu A), influenza B virus (Flu B), mycoplasma pneumoniae (MP), respiratory syncytial virus (RSV), parainfluenza virus (PIV), adenovirus (ADV), and Chlamydia pneumoniae (CP), in outpatient and inpatient children (aged 0-18 years) with influenza-like symptoms who sought medical care at Beijing Children's Hospital, from January 2022 to March 2023. A total of 43 663 children were included in the study, of which 27 903 tested positive for respiratory pathogens with a total detection rate of 63.91%. Flu A had the highest detection rate of 69.93% (27 332/39 084), followed by MP about 13.22% (380/2 875). The total detection rate of RSV, PIV and ADV was 7.69% (131/1 704). Flu B had a detection rate of 0.16% (64/39 084). No CP was detected in this study. A total of 7 cases of dual infections were detected, with a detection rate of 0.41% (7/1 704). The Chi-square test was used to analyze the differences in detection rates of pathogens among different genders, age groups, and different seasons. Among the seven pathogens, only Flu A had statistically significant differences in gender (χ2=16.712, P<0.001). The detection rates of Flu A and MP showed an increasing trend with age (both P trend<0.001), while the detection rates of RSV and PIV showed a decreasing trend with age (both P trend<0.001). Flu A had its epidemic peak in winter and spring, with detection rates of 61.30% (3 907/6 374) and 77.47% (23 207/29 958) respectively; MP and PIV had higher detection rates in autumn (25.14% and 7.64% respectively); RSV showed a relatively higher detection rate in winter (8.69%); Flu B and ADV had lower detection rates throughout the study period (0.16% and 1.17% respectively). In conclusion, children with ILI in 2022-2023 were mainly infected with a single respiratory pathogen, and occasionally dual pathogen infections were observed. Among them, the detection rate of Flu A was the highest, and only Flu A showed a gender difference in detection rate. As the age of the children patients increased, the detection rate of Flu A and MP showed an increasing trend, while RSV and PIV showed a decreasing trend. The prevalence of Flu A, Flu B, MP, PIV, and RSV were seasonal.

Kinetics of Strand Displacement Reaction with Acyclic Artificial Nucleic Acids.

Toehold-mediated strand displacement (TMSD) reaction, one of the DNA nanotechnologies, has great potential as s biological programmable platform in the cellular environment. Various artificial nucleic acids have been developed to improve stability and affinity for biological applications. However, the lack of understanding of the kinetics of TMSD reaction among artificial nucleic acids has limited their applications. We herein systematically characterized the kinetics of TMSD reactions with acyclic xeno nucleic acids (XNAs): serinol nucleic acid (SNA), acyclic D-threoninol nucleic acid (D-aTNA), and acyclic L-threoninol nucleic acid (L-aTNA). We found that the strand displacement reactions by D-aTNA and by L-aTNA were highly dependent on temperature. D-aTNA and L-aTNA systems were orthogonal to each other, and chirality of the input can be switched by using SNA as an interface. We also applied TMSD reactions of XNAs to a seesaw gate amplification system which utilizes the orthogonality. This work will contribute to the developments of thermoresponsive and bioorthogonal nucleic acid circuits.