L-citrulline is a nonprotein amino acid that plays an important role in human health and has great market demand. Although microbial cell factories have been widely used for biosynthesis, there are still challenges such as genetic instability and low efficiency in the biosynthesis of L-citrulline. In this study, an efficient, plasmid-free, non-inducible L-citrulline-producing strain of Escherichia coli BL21(DE3) was engineered by combined strategies. Firstly, a chassis strain capable of synthesizing L-citrulline was constructed by block of L-citrulline degradation and removal of feedback inhibition, with the L-citrulline titer of 0.43 g/L. Secondly, a push-pull-restrain strategy was employed to enhance the L-citrulline biosynthesis, which realized the L-citrulline titer of 6.0 g/L. Thirdly, the NADPH synthesis and L-citrulline transport were strengthened to promote the synthesis efficiency, which achieved the L-citrulline titer of 11.6 g/L. Finally, fed-batch fermentation was performed with the engineered strain in a 3 L fermenter, in which the L-citrulline titer reached 44.9 g/L. This study lays the foundation for the industrial production of L-citrulline and provides insights for the modification of other amino acid metabolic networks.
Citrulline/biosynthesis* ; Escherichia coli/genetics* ; Metabolic Engineering/methods* ; Fermentation ; NADP/biosynthesis*

ObjectiveTo determine the prevalence and determinants of Mycobacterium tuberculosis latent infection among primary and secondary school students in Cixi City, Zhejiang Province, so as to provide references for the prevention and control of tuberculosis in school settings. MethodsInterferon-γ release assay (IGRA) testing was performed to fourth-grade primary school students , as well as to those grade 7 and grade 10 students of the academic year 2024‒2025 in Cixi City. Individuals tested positive for IGRA were subsequently subjected to chest X-ray examination and sputum tests (including three smear microscopy examinations and one mycobaterial culture), and epidemiological investigations were carried out for confirmed cases. Infection rates were compared across student categories by χ² tests, while factors influencing infection were analysed through multivariate logistic regression. ResultsA total of 36 214 students completed tuberculosis screening, with an infection rate of 0.72% (260/36 214). The tuberculosis infection rates among fourth-grade primary school students, non boarding grade 7 students, boarding grade 7 students, grade 10 students of senior high school and of vocational high school were 0.68% (89/13 139), 0.75% (86/11 501), 0.51% (13/2 553), 0.76% (52/6 819), and 0.91% (20/2 202), respectively. Multivariate logistic regression analyses indicated that students with a history of close contact with tuberculosis patients (OR=21.435, P<0.001) had a higher risk of tuberculosis infection, students with a geographic origin outside Zhejiang Province (OR=1.485, P=0.002) had a higher risk of infection than those within Zhejiang Province. Furthermore, students from ethnic minority classes (OR=4.232, P<0.001) might be high-risk groups for tuberculosis infection in high school settings. One IGRA-positive student was confirmed as bacteriologically positive pulmonary tuberculosis by liquid culture of sputum collected one month later. ConclusionSchools should prioritize tuberculosis screening. Students with a history of close contact, those with a geographic origin outside Zhejiang Province, and those enrolled in minority classes should be taken as priority targets for future tuberculosis screening programmes. A tracking and follow-up system must be established for IGRA-positive students to prevent persistent transmission of Mycobacterium tuberculosis within the school settings.

Ischemic stroke is the leading cause of disability and mortality worldwide. The blood‒brain barrier (BBB) is the first line of defense after ischemic stroke. Disruption of the BBB induced by brain microvascular endothelial cells (BMECs) dysfunction is a key event that triggers secondary damage to the central nervous system, where blood-borne fluids and immune cells penetrate the brain parenchyma, causing cerebral edema and inflammatory response and further aggravating brain damage. Here, we develop a novel artificial mesenchymal stem cell (MSC) extracellular vesicles by integrating MSC membrane proteins into liposomal bilayers, which encapsulated miR-132-3p with protective effects on BMECs. The artificial extracellular vesicles (MSCo/miR-132-3p) had low immunogenicity to reduce non-specific clearance by the mononuclear phagocytosis system (MPS) and could target ischemia-injured BMECs. After internalization into the damaged BMECs, MSCo/miR-132-3p escaped the lysosomes via the H_II phase transition of 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE) and decreased cellular reactive oxygen species (ROS) and apoptosis levels by regulating the RASA1/RAS/PI3K/AKT signaling pathway. In the transient middle cerebral artery occlusion (tMCAO) models, MSCo/miR-132-3p targeted impaired brain regions (approximately 9 times the accumulation of plain liposomes at 12 h), reduced cerebral vascular disruption, protected BBB integrity, and decreased infarct volume (from 44.95% to 6.99%).

OBJECTIVE To investigate the anti-inflammatory effect of electroacupuncture in mice with chronic obstructive pul-monary disease(COPD)and its underlying mechanisms.METHODS Forty C57BL/6 mice were randomly divided into normal group,model group,electroacupuncture(EA)group,vagotomy group,and vagotomy+EA group,with 8 mice in each group.Except for the normal group,all groups were exposed to cigarette smoke for 12 weeks to establish a COPD model.After model establishment,the vagotomy group and the vagotomy+EA group underwent left cervical vagotomy before EA.EA treatment was performed at the Feishu(BL13)and Zusanli(ST36)acupoints once daily for 20 minutes for a total of 14 days.After EA,the pulmonary ventilation function of the mice was detected by a pulmonary function analysis system;lung tissue pathology was observed by HE staining;the levels of inter-leukin(IL)-6,tumor necrosis factor-α(TNF-α),IL-10,and transforming growth factor-β(TGF-β)in lung tissue were detected by ELISA;the expression of CD86 and CD206 proteins in lung tissue was detected by Western blot;the distribution of F4/80+CD86+(M1 type)and F4/80+CD206+(M2 type)cells in lung tissue was determined by flow cytometry;the expression of CD86 and CD206 in lung tissue was observed by immunofluorescence.RESULTS Compared with the normal group,the model group showed significantly decreased lung function(P<0.01),obvious lung pathological damage,increased M1 proportion,IL-6,TNF-α,CD86 content and expression(P<0.05,P<0.01),and decreased M2 proportion,IL-10,TGF-β,CD206 content and expression(P<0.01).Compared with the model group,the EA group showed varying degrees of improvement in lung function and pathology;the M1 proportion,IL-6,TNF-α,and CD86 were reduced(P<0.05,P<0.01),while the M2 proportion,IL-10,TGF-β,and CD206 were increased(P<0.05,P<0.01).The vagotomy group showed worsened lung function and pathology,increased IL-6,TNF-α,and CD86 content and expression(P<0.05,P<0.01),and decreased IL-10,TGF-β,and CD206 content and expression(P<0.05,P<0.01).Compared with the EA group,the vagotomy+EA group showed increased M1 proportion,IL-6,TNF-α,and CD86 content and expression(P<0.01),and decreased M2 proportion,IL-10,TGF-β,and CD206 content and expression(P<0.05,P<0.01).CONCLUSION EA at Feishu(BL13)and Zusanli(ST36)acupoints can improve lung function and pulmonary inflammation in COPD mice,promoting the polarization of alveolar macrophages from M1 to M2,which is mediated by the vagus nerve.

Vertebral refracture following percutaneous vertebral augmentation (PVA) is commonly seen in elderly patients with osteoporotic thoracolumbar compression fractures (OTLCF). It can lead to recurrent pain, loss of vertebral height, progression of kyphosis, and even neurological dysfunction, significantly impairing patients′ quality of life. Current diagnosis and treatment face multiple challenges, including high misdiagnosis rate, difficulty in choosing between surgical and non-surgical treatment options, lack of standardized surgical protocols, interference from intralesional bone cement during procedures, inadequate stability of internal fixation in osteoporotic bone, and suboptimal compliance of anti-osteoporotic therapy. Establishing a standardized diagnostic and therapeutic framework is urgently needed. To standardize the management process and improve outcomes for vertebral refractures after PVA in elderly OTLCF patients, Spinal Trauma Group of the Orthopedic Branch of Chinese Medical Doctor Association organized experts in the field to develop Guideline for the diagnosis and treatment of vertebral refracture after percutaneous vertebral augmentation in elderly patients with osteoporotic thoracolumbar compression fractures ( version 2025), based on current literature and clinical experience, and adhering to principles of scientific rigor and clinical applicability. A total of 11 recommendations were proposed, encompassing diagnosis, treatment, and rehabilitation of vertebral refracture after PVA in elderly patients with OTLCF, aiming to provide a foundation for a standardized management.

Objective: To explore the diagnosis, treatment and prognosis of primary prostatic signet ring cell carcinoma (SRCC), so as to provide reference for the clinical diagnosis and treatment. Methods: A retrospective analysis was conducted on the clinical data of 6 patients with primary prostatic SRCC treated in Nanjing Drum Tower Hospital during Nov.2020 and Sep.2024.The clinical manifestations, imaging features, treatment methods, histological characteristics and prognosis were summarized. Results: The average age of the patients was (72.00±4.28) years.Varying degrees of dysuria occurred in 4 patients. All patients underwent multi-parametric magnetic resonance imaging (mpMRI) examination before surgery, and the results indicated typical prostate cancer.Preoperative biopsies showed high-grade (Gleason 8-10) prostate acinar adenocarcinoma.Postoperative pathological diagnoses were mixed types of prostate acinar adenocarcinoma and SRCC, and no metastasis was found in the pelvic lymph nodes.All patients were followed up for 1 to 46 months after surgery and are currently alive.Robot-assisted laparoscopic radical prostatectomy only was performed in 3 cases; apalutamide and leuprolide/triptorelin was administered after surgery in 2 cases; bicalutamide + goserelin was administered after surgery in 1 case, who developed bladder metastasis of prostate cancer 24 months later, and the serum prostate-specific antigen (PSA) concentration decreased to a safe level (<0.2 ng/mL) after the use of darolutamide with radiotherapy.No recurrence or metastasis was found in the remaining patients. Conclusion: Primary prostatic SRCC is a rare and highly aggressive malignant tumor of the prostate.The diagnosis depends on pathological examinations due to lack of specific imaging features and clinical manifestations.The prognosis is poor, and there is currently no standardized treatment.The combined use of surgery, hormonotherapy and radiotherapy can help improve the survival rate of patients.

Vertebral refracture following percutaneous vertebral augmentation (PVA) is commonly seen in elderly patients with osteoporotic thoracolumbar compression fractures (OTLCF). It can lead to recurrent pain, loss of vertebral height, progression of kyphosis, and even neurological dysfunction, significantly impairing patients′ quality of life. Current diagnosis and treatment face multiple challenges, including high misdiagnosis rate, difficulty in choosing between surgical and non-surgical treatment options, lack of standardized surgical protocols, interference from intralesional bone cement during procedures, inadequate stability of internal fixation in osteoporotic bone, and suboptimal compliance of anti-osteoporotic therapy. Establishing a standardized diagnostic and therapeutic framework is urgently needed. To standardize the management process and improve outcomes for vertebral refractures after PVA in elderly OTLCF patients, Spinal Trauma Group of the Orthopedic Branch of Chinese Medical Doctor Association organized experts in the field to develop Guideline for the diagnosis and treatment of vertebral refracture after percutaneous vertebral augmentation in elderly patients with osteoporotic thoracolumbar compression fractures ( version 2025), based on current literature and clinical experience, and adhering to principles of scientific rigor and clinical applicability. A total of 11 recommendations were proposed, encompassing diagnosis, treatment, and rehabilitation of vertebral refracture after PVA in elderly patients with OTLCF, aiming to provide a foundation for a standardized management.