Inteins are unique protein insertion sequences capable of self-excision, enabling the covalent ligation of flanking extein peptides via amide bond formation. This process proceeds spontaneously without requiring external enzymes, cofactors, or chemical reagents, granting inteins exceptional biocompatibility and traceless performance in protein engineering applications. Split inteins represent a specialized and versatile subclass whose splicing domains are encoded by two separate gene fragments rather than a single continuous open reading frame. These fragments, known as the N-terminal (IntN) and C-terminal (IntC) split inteins, associate through non-covalent interactions including hydrophobic forces, hydrogen bonds, and van der Waals forces to assemble into an active three-dimensional structure, which then drives efficient extein ligation and enables protein trans-splicing. Protein trans-splicing mediated by split inteins has become a cornerstone for traceless protein ligation owing to its high specificity and irreversibility, fundamentally reshaping strategies for protein modification, assembly, and functional regulation. Compared with traditional chemical ligation methods, split intein systems require no complex chemical derivatization of peptide fragments and can operate efficiently at micromolar concentrations under physiological conditions, thus avoiding structural and functional damage caused by organic reagents. In contrast to enzymatic ligation tools such as sortase, split inteins eliminate the need for additional enzymes or cofactors, simplifying reaction systems, reducing costs, and minimizing non-specific side products. These distinctive advantages render split inteins highly promising for applications in chemical biology, synthetic biology, and biopharmaceutical development. In recent years, deepened mechanistic understanding has established structure-guided rational design as the primary approach to overcoming key limitations of split inteins, including intrinsic aggregation propensity, strict extein sequence dependence, and limited splicing efficiency. Bioinformatic tools have been used to identify aggregation-prone regions in the IntN fragment, and site-directed mutagenesis of hydrophobic residues, relocation of split sites, or removal of misfolding-prone sequences has substantially reduced in vitro aggregation and improved soluble expression and assembly activity. Rational engineering of catalytic residues and adjacent flexible loops has relaxed strict amino acid preferences at extein junctions, enhancing sequence tolerance and reducing the risk of functional impairment in target proteins. Consensus design based on multiple sequence alignments has yielded ultra-fast splicing variants such as Cfa DnaE and Cat-TerL, which exhibit significantly accelerated kinetics and improved tolerance to denaturing conditions. Meanwhile, advances in structural biology have further clarified the conformational dynamics and catalytic mechanisms of splicing, supporting the precise design of high-performance intein modules. On this basis, electrostatic interaction tuning and metagenomic screening have yielded multiple mutually orthogonal split intein pairs, enabling selective multi-fragment protein ligation and providing new routes for the efficient synthesis of large multi-domain functional proteins. With these engineered split inteins offering continuously improved performance and expanded applicability, protein trans-splicing has been widely applied in numerous cutting-edge areas of protein research and biomedicine. In gene delivery, split intein-based systems overcome the packaging limit of adeno-associated viral vectors, enabling the accurate reconstitution of large therapeutic proteins and base editors in target cells, thereby enhancing the efficacy and scope of gene therapy for genetic diseases. In internal protein sequence editing, split inteins mediate precise sequence replacement and modification in flexible regions or loops of target proteins, without the need for complex multi-step ligation and protein refolding involved in traditional protein semisynthesis. In protein-protein interaction studies, intein-mediated splicing covalently captures transient and weak intracellular complexes, enabling sensitive, high-throughput interaction detection and drug screening. In synthetic biology, conditionally controllable splicing systems support the construction of diverse intracellular and cell-surface biological logic gates for the precise regulation of cellular behavior. In mechanistic biochemical research, split inteins enable photocatalytic proximity labeling and site-specific tagging, allowing the preparation of homogeneous protein samples carrying precise post-translational modifications such as ubiquitination and polyglutamylation for chromatin interactome analysis and epigenetic studies. Moreover, covalent trapping strategies using split inteins stabilize transient enzymatic intermediates, providing unprecedented insights into molecular mechanisms such as nucleosome ubiquitination that are difficult to elucidate using conventional methods. This review systematically summarizes key technological advances in split inteins over the past decade, highlighting engineering strategies, mechanistic insights, and the development of orthogonal components. It comprehensively surveys emerging applications at the frontiers of protein research, analyzes current core challenges, and proposes future directions, particularly emphasizing artificial intelligence-driven de novo design and novel splicing pathways to break existing technical bottlenecks. By enabling traceless, efficient, and versatile protein manipulation, split inteins continue to serve as indispensable tools that drive innovation in protein engineering and fundamental life science research.

Objective This study reports on the obligatory parasitism of water mites Arrenurus sp. on Anopheles messeae at the Manzhouli Port, Inner Mongolia, China. Methods Duing July 2024, a survey on the mosquito diversity was conducted at the Manzhouli Port. Captured mosquitoes and their ectoparasites were identified to species level. Results A total of 1840 adult mosquitoes were collected, representing species from three genera: Culex(Cx. modestus, Cx. pipiens pallens), Aedes(Ae. dorsalis, Ae. flavidorsalis, Ae. flavescens), and Anopheles (An. messeae). Among all the mosqutioes specimens,3 out of 150 captured An. messeae were found to carry ectoparasitic mites, with number of 2,4,27 mites separately. Morphological and molecular identification reached the same result as water mites(Hydrachnidiae, Hydracrina). COI gene sequence showed 94% similarity with the closest species Arrenurus truncatellus. Conlusions Literature review suggests water mites are host-specific parasitism of mosquito species and herein with the first record of Arrenurus sp. parasiting on An. Messeae in the most high-latitude region globally.

ObjectiveTo clarify whether METTL14 mediates the core role of acupuncture at Neiguan (PC6) in promoting myelination and improving behavior in young autistic rats through gene intervention technology. MethodsThe ASD model was established by intraperitoneal injection of valproic acid (VPA) in pregnant rats. Male offspring were intracerebroventricularly injected with adenovirus-packaged METTL14 shRNA (sh-METTL14) or its control (sh-NC) on postnatal day 1, with a model group set as well. Subsequently, the juvenile rats were divided into model group, acupuncture group, acupuncture+sh-NC group, and acupuncture+sh-METTL14 group. The acupuncture group received acupuncture at Neiguan (PC6) from postnatal day 7, once daily for 21 consecutive days. Neurobehavioral changes were evaluated by behavioral tests; METTL14 knockdown efficiency and the expression of METTL14, METTL3, and PTEN were detected by quantitative real-time PCR (qRT-PCR) and Western blot (WB); PTEN m⁶A levels were measured by RNA immunoprecipitation-qPCR (RIP-qPCR); myelin ultrastructure, expression of myelin basic protein (MBP) and neurofascin 155 (NF155), and dendritic spine density were observed using transmission electron microscopy (TEM), enzyme-linked immunosorbent assay (ELISA), immunofluorescence, qRT-PCR, and primary neuron culture. ResultsBehaviorally, knockdown of METTL14 significantly counteracted the beneficial effects of acupuncture in improving self-grooming, open field exploration, three-chamber social interaction, and Morris water maze learning and memory (P<0.05, P<0.01). Compared with the acupuncture+sh-NC group, the acupuncture+sh-METTL14 group showed significantly decreased mRNA and protein expression of hippocampal METTL14 (P<0.01), and the upregulating effects of acupuncture on METTL3 and PTEN expression were reversed (P<0.01). Meanwhile, knockdown of METTL14 significantly inhibited the acupuncture-induced increase in PTEN m⁶A levels (P<0.01). Morphologically, knockdown of METTL14 attenuated the improvement of myelin structure by acupuncture, reversed the downregulation of MBP and upregulation of NF155 induced by acupuncture, and blocked the increase in dendritic spine density (P<0.05, P<0.01). ConclusionMETTL14 is a key molecule mediating the therapeutic effect of acupuncture at Neiguan. Acupuncture at Neiguan upregulates METTL14, thereby enhancing m⁶A methylation modification of PTEN mRNA to stabilize its expression, ultimately promoting myelin development and improving behavioral symptoms in ASD juvenile rats. This preliminarily reveals the modern biological connotation of “opening Xuanfu and dredging myelin”.

ObjectiveTo clarify whether METTL14 mediates the core role of acupuncture at Neiguan (PC6) in promoting myelination and improving behavior in young autistic rats through gene intervention technology. MethodsThe ASD model was established by intraperitoneal injection of valproic acid (VPA) in pregnant rats. Male offspring were intracerebroventricularly injected with adenovirus-packaged METTL14 shRNA (sh-METTL14) or its control (sh-NC) on postnatal day 1, with a model group set as well. Subsequently, the juvenile rats were divided into model group, acupuncture group, acupuncture+sh-NC group, and acupuncture+sh-METTL14 group. The acupuncture group received acupuncture at Neiguan (PC6) from postnatal day 7, once daily for 21 consecutive days. Neurobehavioral changes were evaluated by behavioral tests; METTL14 knockdown efficiency and the expression of METTL14, METTL3, and PTEN were detected by quantitative real-time PCR (qRT-PCR) and Western blot (WB); PTEN m⁶A levels were measured by RNA immunoprecipitation-qPCR (RIP-qPCR); myelin ultrastructure, expression of myelin basic protein (MBP) and neurofascin 155 (NF155), and dendritic spine density were observed using transmission electron microscopy (TEM), enzyme-linked immunosorbent assay (ELISA), immunofluorescence, qRT-PCR, and primary neuron culture. ResultsBehaviorally, knockdown of METTL14 significantly counteracted the beneficial effects of acupuncture in improving self-grooming, open field exploration, three-chamber social interaction, and Morris water maze learning and memory (P<0.05, P<0.01). Compared with the acupuncture+sh-NC group, the acupuncture+sh-METTL14 group showed significantly decreased mRNA and protein expression of hippocampal METTL14 (P<0.01), and the upregulating effects of acupuncture on METTL3 and PTEN expression were reversed (P<0.01). Meanwhile, knockdown of METTL14 significantly inhibited the acupuncture-induced increase in PTEN m⁶A levels (P<0.01). Morphologically, knockdown of METTL14 attenuated the improvement of myelin structure by acupuncture, reversed the downregulation of MBP and upregulation of NF155 induced by acupuncture, and blocked the increase in dendritic spine density (P<0.05, P<0.01). ConclusionMETTL14 is a key molecule mediating the therapeutic effect of acupuncture at Neiguan. Acupuncture at Neiguan upregulates METTL14, thereby enhancing m⁶A methylation modification of PTEN mRNA to stabilize its expression, ultimately promoting myelin development and improving behavioral symptoms in ASD juvenile rats. This preliminarily reveals the modern biological connotation of “opening Xuanfu and dredging myelin”.

The accumulation of uremic toxins such as urea nitrogen, blood creatinine, and uric acid of patients with renal failure in vivo would lead to aggravated kidney damage. In this study, coated aldehyde oxy-starch (CAO) was used as an adsorbent to investigate its in vitro adsorption performance on renal failure indexes for urea, indoxyl sulfate (INS), monomethylamine (MMA), dimethylamine (DMA), uric acid (UA), and creatinine (Cr). The effects of variables such as pH, temperature, concentration, dosage, and time on the adsorption capacity of CAO were systematically investigated, employing analytical techniques of high-performance liquid chromatography (HPLC) and gas chromatography (GC). The results revealed that CAO exhibited a strong adsorption capacity for urea, INS, and MMA, alongside a moderate adsorption capacity for DMA, UA, and Cr. The adsorption kinetics and thermodynamic studies indicated that the adsorption of urea and UA by CAO were fitted in pseudo-first-order kinetics, and the adsorption isotherm aligned with the Freundlich adsorption model. The enthalpy change ΔH of urea in adsorption was in the range of 40 to 60 kJ·mol^-1, which demonstrated the presence of strong adsorption force due to the interactions of coordinating groups. The ΔH of UA was greater than 80 kJ·mol^-1, indicating the generation of chemical bonds during the adsorption. Both of them, Gibbs free energy ΔG was less than 0, within the range of -20 to 0 kJ·mol^-1, suggested that the adsorption of urea and UA by CAO occurred spontaneously as physical adsorption process. The adsorption entropy ΔS of urea and UA was > 0, which indicated an increase in entropy throughout the adsorption. The infrared spectroscopygram showed the formation of a chemical bond, specifically the imine bond, following the adsorption of urea by CAO, thereby indicating a chemical reaction during the adsorption. This study elucidates the adsorption mechanism of CAO on various indexes of renal failure, providing a scientific basis for its clinical usage.

Objective:To investigate the situation of computed tomography(CT)equipment and socio economic development of various grades and classifications of medical institutions in Jiangsu Province,and to analyze the interrelationship between them.Methods:From October 20,2023 to November 20,2023,a questionnaire survey was conducted on imported and domestic CT equipment of various grades and classifications of medical institutions in 13 prefecture-level cities in Jiangsu Province through online questionnaire survey of"questionnaire star".The gross domestic product(GDP)of each prefecture-level city in Jiangsu province was used as an indicator of measuring the level of socio-economic development in the region.The CT number,the row number of detector,quality of image,the total examination case number of daily average and the daily average case number of single machine examination of medical institutions of various grades and classifications of 13 prefecture-level cities were used to conduct correlation analysis with GDP values of various districts.Results:A total of 910 questionnaires were distributed,and 512 questionnaires were retrieved.There were 482 valid questionnaires in the 512 questionnaires,and the valid rate was 94.15,which involved to 482 various grade and classification institutions of 13 prefecture-level cities in Jiangsu province.The number of imported and domestic CT equipment in the 13 prefecture-level cities of Jiangsu Province positively correlated with the GDP of each city(r=0.882,0.880,P<0.001).The number of imported CT equipment with 64 rows and more than 64 rows,and with less than 64 rows,and the number of domestic CT equipment with 64 rows and more than 64 rows,and with less than 64 rows all positively correlated with the GDP of each city(r=0.880,0.881,0.736,0.897,P<0.05).The total number of daily average of examinations for imported and domestic CT equipment of 13 prefecture-level cities positively correlated with the GDP of each city(r=0.774,0.814,P<0.05).There were no significant difference in the image quality and the daily average case number of single machine examination between the domestic CT equipment and the imported CT equipment(P>0.05).Conclusion:The medical institutions of city with high level of economic development have more quantitative and more high-end CT equipment,and the quality of image of domestic CT equipment is equal to that of imported CT equipment regardless of the high and low level of economic development.

Objective:To observe the clinical efficacy of the modified crowbar-assisted minimally invasive Chevron osteotomy for the treatment of hallux valgus.Methods:A total of 42 patients with hallux valgus who underwent modified crowbar-assisted minimally invasive Chevron osteotomy at Huashan Hospital of Fudan University for hallux valgus from January 2019 to July 2022 were retrospectively analyzed. There were 3 males and 39 females, aged 42.3±8.7 years (range, 26-60 years); 18 left-sided and 24 right-sided, with body mass index 22.9±2.3 kg/m 2. According to the size of the hallux valgus angle (HVA), 26 patients were divided into the mild group (15°≤HVA<20°) and 16 patients were divided into moderate group (20°≤HVA≤40°). All patients were treated with modified crowbar-assisted Chevron osteotomy. The preoperative and postoperative HVA, intermetatarsal angle (IMA), distal metatarsal articular angle (DMAA), visual analogue scale (VAS) and American Orthopaedic Foot and Ankle Society metatarsophalangeal interphalangeal scale (AOFAS Hallux MTP-IP scale) were compared. Results:All patients successfully completed the operation and were followed up for an average of 22.3±6.5 months (range, 18-30 months). The HVA, IMA, and DMAA in the mild group at the last follow-up were 6.6°±1.8°, 8.1°±1.8°, and 4.3°±1.1°, respectively, which were significantly lower than those before operation 17.8°±1.4°, 12.5°±1.5°, and 7.6°±2.4° ( P<0.05). The HVA, IMA, and DMAA in the moderate group at the last follow-up were 7.6°±2.1°, 8.8°±1.6°, and 4.8°±2.9°, respectively, which were significantly lower than those before operation 32.3°±3.5°, 14.8°±3.5°, and 12.7°±5.4° ( P<0.05). At the last follow-up, there was no significant difference in HVA, IMA, or DMAA between the two groups ( P>0.05). The differences of HVA, IMA, and DMAA before and after operation in the moderate group were 24.7°±2.6°, 6.0°±2.3°, and 7.9°±3.8°, respectively, which were greater than those in the mild group 11.2°±1.7°, 4.4°±1.6°, and 3.3°±1.6°, and the differences were statistically significant ( P<0.05). At the last follow-up, the VAS score of the mild group decreased from 2.6±2.0 before surgery to 0.4±0.2, and the difference was statistically significant ( t=6.014, P<0.001). The VAS score of the moderate group decreased from 3.2±2.2 before surgery to 0.4±0.3, the difference was statistically significant ( t=8.777, P<0.001). The preoperative AOFAS Hallux MTP-IP scale of the toe metatarsal joint in the mild group and the moderate group were 71.6±5.9 and 64.3±7.8, respectively, which increased to 93.3±6.0 and 92.3±6.0 at the last follow-up, and the difference was statistically significant ( P<0.05). At the last follow-up, there was no significant difference in AOFAS Hallux MTP-IP scale between the two groups ( P>0.05). Twenty-two of the 26 patients in the mild group were satisfied, and 14 of the 16 patients in the moderate group were satisfied, and the difference in satisfaction between the two groups was not statistically significant ( P>0.05). Conclusion:The clinical efficacy of the modified crowbar-assisted minimally invasive Chevron osteotomy in the treatment of hallux valgus is satisfactory, and it can effectively correct the hallux valgus deformity and improve the function of the metatarsophalangeal joint.

Objective:To explore the safety and efficacy of intraosseous regional administration (IORA) of vancomycin for preventing infection in primary total knee arthroplasty (TKA).Methods:A total of 124 patients with knee osteoarthritis undergoing TKA between February 2024 and May 2024 at nine hospitals were enrolled. Preoperative infection prophylaxis involved either IORA (0.5 g vancomycin administered via intraosseous regional infusion before incision) or intravenous infusion (1 g vancomycin via peripheral vein). The IORA group included 15 males and 47 females with a median age of 66.5 years (range, 60.0-70.0 years), while the intravenous group included 14 males and 48 females with a median age of 66.0 years (range, 61.8-70.3 years) years. Intraoperative samples were collected including fat and synovium tissues after incision, before prosthesis placement, and after tourniquet release; distal femoral cancellous bone during femoral osteotomy; proximal tibial cancellous bone during tibial osteotomy; proximal intercondylar cancellous bone before prosthesis placement; and peripheral blood from non-infused arms at surgery initiation and after tourniquet release. Vancomycin concentrations were measured using liquid chromatography-tandem mass spectrometry. Vital sign changes were recorded from admission to 5~10 minutes post-IORA (IORA group) or post-incision (intravenous group). Follow-ups were conducted on postoperative day 1 and 3, and at 1 and 3 months, to document complications including IORA-related adverse events, periprosthetic joint infections, surgical site infections, red man syndrome, acute kidney injury, deep vein thrombosis and so on.Results:Vancomycin concentrations in bone, fat, and synovial tissue samples were significantly higher in the IORA group than in the intravenous group ( P<0.05), while vancomycin concentrations in blood samples were significantly lower in the IORA group than in the intravenous group ( P<0.05). Only 7.3%(41/558) of tissue samples in the IORA group had vancomycin concentrations below 2.0 μg/g (the minimum inhibitory concentration of vancomycin against coagulase-negative staphylococcus), compared to 59.3%(331/558) in the intravenous group (χ 2=11.285, P<0.001). In the intravenous group, 16.9%(21/124) of blood samples had vancomycin concentrations exceeding 15.0 mg/L (the threshold associated with a significantly increased risk of nephrotoxicity), while all concentrations in the IORA group were below this threshold, the difference was statistically significant (χ 2=22.943, P<0.001). There were no statistically significant difference ( P>0.05) in vital signs changes before and after vancomycin administration between the two groups. Two patients in the intravenous group experienced incision exudate, while no other related complications occurred in either group. Conclusions:Compared to the traditional intravenous infusion of 1 g vancomycin, intraosseous injection of a low dose (0.5 g) of vancomycin achieves higher local tissue concentrations in the knee joint with a lower incidence of adverse reactions and is safe for infection prophylaxis. Despite guidelines not recommending the routine use of vancomycin for preventing infection after primary TKA, intraosseous injection of 0.5 g vancomycin may be considered intraoperatively for primary TKA in the following scenarios: patients in medical institutions with a high prevalence of methicillin-resistant staphylococcus aureus (MRSA) infections, patients with potential preoperative MRSA colonization, or patients with cephalosporin allergy.

Objective:To investigate clinical characteristics, treatment approaches, and prognosis of drug-induced hypersensitivity syndrome (DIHS) in children.Methods:A retrospective analysis was performed on clinical data from pediatric inpatients with DIHS in Department of Dermatology, Beijing Children's Hospital from 2009 to 2023. The clinical data included demographic characteristics, clinical manifestations, laboratory findings, treatment regimens, and outcomes.Results:A total of 103 children with DIHS were included, comprising 54 males (52.4%) and 49 females (47.6%), with ages ( M [ Q1, Q3]) of 2.3 (1.2, 4.5) years. Primary causative drugs were antibiotics (52 cases, 45.2%), antiepileptic drugs (41 cases, 35.7%), and nonsteroidal anti-inflammatory drugs (19 cases, 16.5%), with a median latency period of 12 days. All patients presented with rashes, including 72 (69.9%) with maculopapular rashes, 69 (67.0%) with edema (including 46 with facial edema). Lip involvement occurred in 25 cases (24.3%), and mucosal involvement was noted in 11 cases (10.7%). Additionally, 102 (99.0%) patients had fever, and 79 (76.7%) presented with lymphadenectasis. Eosinophilia was present in 64 cases (62.1%). Among 84 patients tested for atypical lymphocytes, 51 (60.7%) showed elevated percentages of atypical lymphocytes. Liver involvement was noted in 94 cases (91.3%), followed by pulmonary involvement in 31 (30.1%), gastrointestinal symptoms in 25 (24.3%), cardiac involvement in 14 (13.6%), renal involvement in 10 (9.7%), and pancreatic involvement in 7 cases (6.8%). Among 82 patients tested for blood immunocytes, 49 (59.8%) showed decreased percentages of B lymphocytes, and 69 (84.1%) showed decreased percentages of natural killer cells. Of 88 patients tested for serum immunoglobulins, 40 (45.5%) showed decreased IgA levels. Among 20 patients tested for serum cytokines, 15 (75.0%), 15 (75.0%), 13 (65.0%), and 12 (60.0%) showed elevated levels of interleukin (IL) -5, IL-6, IL-10, and interferon-γ, respectively. All patients received systemic glucocorticoid therapy, among whom 86 additionally received intravenous immunoglobulin therapy, 4 received Janus kinase inhibitors, and 3 received dupilumab. Five patients died, 9 developed hemophagocytic lymphohistiocytosis, 6 developed bronchiolitis obliterans, and 5 experienced long-term immune-related sequelae. Conclusions:Among these children with DIHS, antibiotics were the most common causative drugs, and the latency period could be shorter than 2 weeks. In addition to the common involvement of the liver and lungs, gastrointestinal and cardiac impairments were relatively frequent, while renal involvement was rare. Immunological features included decreased percentages of B lymphocytes and natural killer cells, reduced IgA levels, and elevated levels of cytokines such as IL-5, IL-6, IL-10, and interferon-γ.

Body weight abnormalities, including overweight, obesity, and underweight, have become a dual public health challenge in Chinese adults: overweight and obesity lead to a variety of chronic complications, while underweight increases the risks of malnutrition, sarcopenia, and organ dysfunction. To systematically address these issues, multidisciplinary experts in endocrinology, sports science, nutrition, and psychiatry from various regions have held multiple weight management seminars. Based on the latest epidemiological data and clinical evidence, they expanded the guideline to include assessment and intervention strategies for underweight, in addition to the core content of obesity management. This guideline outlines the etiological mechanisms, evaluation methods, and multidimensional management strategies for overweight and obesity, covering key areas such as diagnosis and assessment, medical nutrition therapy, exercise prescription, pharmacological intervention, and psychological support. It is intended to provide a scientific and standardized approach to weight management across the adult population, aiming to curb the rising prevalence of obesity, mitigate complications associated with abnormal body weight, and improve nutritional status and overall quality of life.