ObjectiveTo investigate whether Huanglian Jiedutang can inhibit neutrophil infiltration in the brains of middle cerebral artery occlusion （MCAO） mice by regulating the expression of neutrophil-related chemokines in exosomes， thereby achieving therapeutic effects. MethodsA total of 130 male specific pathogen-free （SPF） C57BL/6J mice were randomly divided into four groups： Sham-operated group， MCAO model group， Huanglian Jiedutang group （6 g·kg^-1）， and Ginaton group （21.6 mg·kg^-1）， with 10 mice in the Ginaton group and 40 mice in each of the remaining three groups. Mice in the Huanglian Jiedutang group and the Ginaton group were administered the corresponding drugs by oral gavage once daily at a volume of 0.15 mL·（10 g）^-1 for 7 consecutive days， while the sham-operated and model groups received an equal volume of saline via the same route. After 7 days， MCAO surgery was performed. The distal and proximal ends of the right common carotid artery （CCA） were ligated， a small incision was made between the two ligatures， and a silicone rubber-coated monofilament with a rounded tip was inserted into the lumen to occlude the CCA. The filament was left in place for 1 h to establish a focal cerebral ischemia model. At 24 h after modeling， mice were evaluated. Neurological function was assessed using the Longa score. Cerebral infarct volume was measured by 2，3，5-triphenyltetrazolium chloride （TTC） staining. Cerebral blood flow was observed by laser speckle imaging. Hematoxylin and eosin （HE） staining and Nissl staining were used to observe pathological changes in brain tissues. Exosomes were isolated from mouse plasma and brain tissues by ultracentrifugation and molecular size exclusion and identified by electron microscopy， particle size analysis， and protein blotting. Long-chain RNA libraries of exosomes were constructed and sequenced. Real-time quantitative reverse transcription polymerase chain reaction （Real-time PCR） was used to detect the mRNA expression of inflammatory factors and neutrophil-related chemokines in exosomes from plasma and brain tissues of each group. Enzyme-linked immunosorbent assay （ELISA） was used to detect the protein expression of inflammatory factors and neutrophil-related chemokines in exosomes from brain tissues of each group. Immunohistochemistry was used to detect the expression of the neutrophil-specific protein myeloperoxidase （MPO） in the brains of mice in each group. ResultsCompared with the sham-operated group， the model group showed decreased neurological function scores （P<0.01）， obvious cerebral infarction （P<0.01）， reduced cerebral blood flow （P<0.01）， neuronal necrosis in the brain， and decreased numbers of Nissl bodies （P<0.01）. The mRNA expression levels of IL-1β， MPO， CXCL1， CXCL2， CXCL3， CXCL10， CCL2， and CCL3 in exosomes from plasma and brain tissues were significantly increased （P<0.05， P<0.01）. The protein expression levels of IL-1β， MPO， CXCL2， and CXCL10 in exosomes from brain tissues were increased （P<0.05， P<0.01）， and MPO-positive rates and mean optical density values in brain tissues were elevated （P<0.01）. Compared with the model group， the Huanglian Jiedutang group and the Ginaton group showed increased neurological function scores （P<0.05）， reduced cerebral infarct volume （P<0.01）， restored cerebral blood flow （P<0.01）， reduced necrotic cells in the brain， and increased numbers of Nissl bodies （P<0.01）. In the Huanglian Jiedutang group， the mRNA expression levels of IL-1β， MPO， CXCL1， CXCL2， CXCL3， CXCL10， CCL2， and CCL3 in exosomes from plasma and brain tissues were decreased （P<0.05， P<0.01）. The protein expression levels of IL-1β， MPO， CXCL2， and CXCL10 in exosomes from brain tissues were reduced （P<0.05， P<0.01）， and MPO-positive rates and mean optical density values in brain tissues were decreased （P<0.01）. ConclusionHuanglian Jiedutang can effectively regulate the expression of neutrophil-related chemokines in exosomes from plasma and brain tissues of MCAO mice， thereby reducing neutrophil infiltration in the brain and achieving therapeutic effects.

ObjectiveTo evaluate the therapeutic effects of Huanglian Jiedutang on cerebral infarction injury in a mouse model of middle cerebral artery occlusion （MCAO） and to explore its mechanism of action on oligodendrocytes， particularly its potential in myelin repair. MethodsMultiple experimental approaches were used to evaluate cerebral ischemic injury and the effects of drug intervention. Laser speckle imaging was used to detect changes in cerebral blood flow， 2，3，5-Triphenyltetrazolium chloride （TTC） staining was used to measure infarct volume， and neurological function was scored according to the Zea-Longa criteria. Brain tissues were routinely embedded in paraffin and subjected to HE and Nissl staining to observe tissue structure and neuronal damage. Animals were divided into a sham group （n=24）， model group （n=24）， Huanglian Jiedutang group （n=24）， and Ginkgo biloba extract （GBE） group （n=18）. After 1 week of acclimatization， intragastric administration was initiated. The sham and model groups received normal saline， the Huanglian Jiedutang group was administered 1.82 g·kg^-1， and the GBE group was administered 0.432 g·kg^-1 after preparation as a 2.16 g·L^-1 solution. All groups were treated for 5 consecutive days at a dose of 0.2 mL·（10 g）^-¹·d^-¹. The MCAO model was established after the final administration on day 6. Single-cell RNA sequencing was used to analyze brain tissue cellular composition and changes in oligodendrocyte subpopulations. Distinct subpopulations were identified by Uniform manifold approximation and projection （UMAP） dimensionality reduction and unsupervised clustering， and marker gene expression was analyzed. Pathway enrichment and causal inference were further performed using IPA. Finally， real-time quantitative PCR was used to verify mRNA expression changes of myelin-related genes. ResultsCompared with the sham group， the model group showed significantly increased neurological function scores （P<0.01）， significantly impaired blood flow （P<0.01）， significantly enlarged cerebral infarct area （P<0.01）， and pathological changes including disordered cortical structural arrangement， aggravated cytoplasmic vacuolization， and increased Nissl bodies. Compared with the model group， the Huanglian Jiedutang and GBE groups showed significantly decreased neurological function scores （P<0.01）， markedly restored blood flow levels （P<0.01）， significantly reduced cerebral infarct area （P<0.01）， and improvement in cortical structural disorder， alleviation of cytoplasmic vacuolization， and a reduction in Nissl bodies. Single-cell data showed that a myelin-associated oligodendrocyte （Mye-OL） subpopulation existed among oligodendrocytes， which was closely related to myelin generation. Compared with the sham group， the number of Mye-OL cells decreased in the model group. Compared with the model group， the number of Mye-OL cells increased in the Huanglian Jiedutang group. This subpopulation promoted the expression of myelin-related genes， including MOG， MBP， and MAG， via transcription factors such as OLIG1， OLIG2， NKX2-2， and SOX10， thereby regulating myelin generation， restoring cognition， and exerting therapeutic effects on acute cerebral infarction. Compared with the sham group， the mRNA expression levels of OLIG1， OLIG2， NKX2-2， and SOX10 were significantly downregulated in the model group （P<0.01）， and the mRNA expression levels of myelin-related genes， including MOG， MBP， and MAG， were also significantly downregulated （P<0.01）. In contrast， compared with the model group， the Huanglian Jiedutang and GBE groups showed significantly upregulated mRNA expression levels of OLIG1， OLIG2， NKX2-2， and SOX10 （P<0.01）， and significantly upregulated mRNA expression levels of myelin-related genes， including MOG， MBP， and MAG （P<0.01）. ConclusionHuanglian Jiedutang exerts therapeutic effects on acute cerebral infarction by regulating the OLIG1/2-NKX2-2-SOX10 signaling pathway to promote myelin generation by Mye-OL cells.

ObjectiveTo investigate the characteristics of metabolic reprogramming during cerebral ischemia-reperfusion injury using single-cell transcriptome sequencing， analyze the heterogeneity of microglial populations， and evaluate the interventional effects of Huanglian Jiedutang on metabolic abnormalities and neuroinflammation. MethodsA transient middle cerebral artery occlusion （tMCAO） model was used to establish ischemic stroke in mice. Local cerebral blood flow changes were monitored by laser speckle imaging. Neurological impairment was evaluated using the Zea-Longa score， and histopathological damage in brain tissue was observed by HE and Nissl staining. Animals were divided into a sham group， model group， Huanglian Jiedutang group， and Ginkgo biloba extract （GBE） group. After 1 week of acclimatization， intragastric administration was initiated. The sham and model groups received normal saline， the Huanglian Jiedutang group was administered 1.82 g·kg^-1， and the GBE group was administered 0.432 g·kg^-1 after preparation as a 2.16 mg/mL solution. All groups were treated for 5 consecutive days （0.2 mL/10 g/day）， and the tMCAO model was established on day 6 after the final administration. At the molecular level， single-cell RNA sequencing was performed on ischemic hemisphere tissue. Non-negative matrix factorization （NMF） was used to cluster microglial subpopulations， combined with differential expression analysis， metabolic reprogramming assessment， and inflammatory factor correlation analysis to elucidate their functional characteristics in ischemia-reperfusion injury. Transcription factor enrichment analysis was further conducted to identify key regulatory nodes. Finally， PCR was used to detect mRNA expression changes of relevant genes to validate the single-cell sequencing results. ResultsCompared with the sham group， the model group showed increased neurological function scores （P<0.01）， decreased blood flow levels （P<0.01）， disordered cortical structure， increased cytoplasmic vacuolization， and increased Nissl bodies. Compared with the model group， the Huanglian Jiedutang and GBE groups showed decreased neurological function scores （P<0.01）， increased blood flow levels （P<0.01）， alleviated cortical structural disorder， reduced cytoplasmic vacuolization， and decreased Nissl bodies. Single-cell analysis showed that microglia could be divided into five subpopulations. Among them， clusters 3 and 5 exhibited significant pro-inflammatory phenotypes， with marked activation of hypoxia and NF-κB signaling pathways， and were identified as pro-inflammatory subpopulations. Clusters 1 and 2 were enriched in Wnt/β-catenin and transforming growth factor（TGF）-β signaling pathways and exhibited prominent anti-inflammatory and reparative characteristics. Meanwhile， glycolysis-related genes， such as HK2， PFKP， and LDHA， were significantly upregulated in the pro-inflammatory subpopulations. Correlation analysis showed that the expression levels of inflammatory molecules were positively correlated with glycolysis-related gene expression levels， whereas the expression levels of reparative and anti-inflammatory molecules were negatively correlated with glycolysis-related gene expression levels， indicating that microglia rely on the glycolytic pathway for energy acquisition under ischemic conditions. Further single-cell transcriptome analysis revealed that Huanglian Jiedutang effectively downregulated key genes driving metabolic reprogramming （such as HK2， PFKP， and LDHA）， significantly reduced the proportion of microglial subpopulations accompanied by glycolytic reprogramming， and inhibited their transformation toward a damage phenotype， thereby reducing inflammatory injury. Meanwhile， compared with the sham group， the mRNA expression levels of interleukin （IL）-1β， IL-6， tumor necrosis factor（TNF）-α， CCL2， CXCL2， and CSF3 were significantly upregulated （P<0.01） in the model group， whereas the mRNA expression levels of endothelial- and pericyte-related functional genes， including RGS5， PECAM1， VEGFB， and NOS3， were significantly downregulated （P<0.01）. In contrast， compared with the model group， the Huanglian Jiedutang and GBE groups showed significantly decreased mRNA expression levels of IL-1β， IL-6， TNF-α， CCL2， CXCL2， and CSF3 （P<0.01）， and significantly increased mRNA expression levels of endothelial- and pericyte-related functional genes， including RGS5， PECAM1， VEGFB， and NOS3 （P<0.01）. ConclusionHuanglian Jiedutang exerts neuroprotective effects by regulating the metabolic reprogramming state of microglia and modulating their inflammatory levels， thereby inhibiting neuroinflammatory injury.

ObjectiveTo explore the potential mechanism of Xiaoqinglongtang（XQL） in the prevention and treatment of high altitude pulmonary edema（HAPE） by network pharmacology， molecular docking， and molecular dynamics simulation， and to verify it by in vivo animal model. MethodsIn this study， the active ingredients， drug targets， and HAPE-related targets of XQL were collected from BATMAN-TCM， GeneCards， and Online Mendelian Inheritance in Man（OMIM） databases. The protein-protein interaction（PPI） network was constructed by using intersection targets， and the core targets were screened and visualized by Cytoscape software. Functional annotation and pathway analysis of the intersection targets were performed by gene ontology （GO） and Kyoto encyclopedia of genes and genomes （KEGG） functional enrichment. AutoDock and GROMACS were used to evaluate the binding ability of active ingredients to key targets. In the experimental verification part， a mouse model of HAPE induced by hypobaric hypoxia（simulated 6 000 m altitude for 48 h） was established. The control effect was evaluated by hematoxylin-eosin（HE） staining， lung tissue water content， lung tissue wet/dry weight ratio， real-time quantitative polymerase chain reaction（Real-time PCR） detection of gene expression levels， and immunohistochemistry and Western blot detection of key protein expression. ResultsA total of 355 active ingredients of XQL， 2 142 targets， 716 HAPE-related targets， and 236 intersection targets were obtained by network pharmacology analysis. Key core targets such as interleukin （IL）-6， tumor necrosis factor （TNF）， protein kinase B1 （Akt1）， and hypoxia-inducible factor-1α （HIF-1α） were screened. The results of GO analysis of common targets involved 738 biological processes（BP）， 72 cellular components（CC）， and 135 molecular functions（MF）. KEGG analysis effectively enriched two important signaling pathways： Phosphoinositol 3-kinase （PI3K）/Akt and HIF-1α. The results of molecular docking and molecular dynamics simulation showed that the screened active ingredients had good binding ability with key targets. In the HAPE model induced by hypobaric hypoxia（6 000 m， 48 h）， the lung tissue water content， lung tissue wet/dry weight ratio， and pathological injury score of the model group were significantly increased（P<0.01）， accompanied by exudation of a large number of red blood cells in the alveoli and alveolar interstitium， a significant increase in inflammatory cells， a significant widening of the alveolar septum， and mutual fusion between the alveoli. The XQL administration group significantly improved the above pathological changes（P<0.01）. The results of inflammatory factor expression showed that compared with the control group， the model group showed significantly up-regulated expression of TNF-α， IL-6， and IL-1β in the lung tissue（P<0.01）. Compared with the model group， the XQL administration group had significantly decreased expression of inflammatory factors（P<0.05， P<0.01）. The mRNA expression of key pathway related genes PI3K， Akt1， mammalian target of rapamycin（mTOR）， and HIF-1α was significantly increased in the model group（P<0.01）， and decreased in a concentration-dependent manner after XQL administration（P<0.05， P<0.01）. The expression levels of key proteins PI3K， phosphorylation（p）-PI3K， Akt1， p-Akt1， mTOR， p-mTOR， and HIF-1α in lung tissue were analyzed by immunohistochemistry and Western blot. Compared with the blank group， the model group showed increased expression of key proteins（P<0.05， P<0.01）. Compared with the model group， the XQL administration group exhibited decreased expression of key proteins（P<0.05， P<0.01）. ConclusionXQL can reduce lung inflammation and improve HAPE. The mechanism may be related to the regulation of PI3K/Akt/mTOR and HIF-1α pathways. This study provides a new idea and a theoretical basis for the treatment of HAPE with XQL.

ObjectiveHeadspace solid-phase microextraction-gas chromatography-mass spectrometry（HS-SPME-GC-MS） and GC-triple quadrupole MS（GC-QqQ-MS） in combination with non-targeted and targeted metabolomics were employed to systematically analyze the chemical composition differences of Xihuangwan prepared with natural musk and artificial musk， and establish an identification system for them. MethodsThe volatile components of 9 batches of Xihuangwan samples from 8 manufacturers were analyzed by HS-SPME-GC-MS non-targeted metabolomics， and identified by comparing their MS data with the National Institute of Standards and Technology（NIST） spectral library. Orthogonal partial least squares-discriminant analysis（OPLS-DA） was used to identify differential volatile components of Xihuangwan prepared with natural musk and artificial musk. Additionally， GC-QqQ-MS targeted metabolomics was applied to quantify the levels of α-pinene， β-elemene， muscone， dehydroepiandrosterone， bornyl acetate， and octyl acetate in 27 batches of samples from 9 manufacturers. Cluster analysis， principal component analysis（PCA）， and partial least squares-discriminant analysis（PLS-DA） were conducted to further explore the differences in volatile components between Xihuangwan samples prepared with natural musk and artificial musk. ResultsNon-targeted metabolomics identified 291 volatile compounds in Xihuangwan， including alkanes， esters， alkanes， alcohols， ketones， naphthalenes and others. OPLS-DA analysis revealed distinct separation between Xihuangwan samples containing artificial musk（A1， C1， D1， E1， F1， G1， I1） and those containing natural musk（H1， H3）. A total of 30 differential metabolites were identified. The relative contents of these 30 differential metabolites were visualized using a radar chart， revealing significant differences in the levels of octanol， borneol acetate and muscone. Cluster analysis and PCA results from targeted metabolomics indicated that Xihuangwan could be classified into two distinct groups：one composed of natural musk（H1， H3） and the other of artificial musk， sample H2. PLS-DA identified muscone， octyl acetate， and dehydroepiandrosterone as key differential volatile components. Although no significant difference was observed in the content of octyl acetate between the two groups， statistically significant differences were found for muscone and dehydroepiandrosterone（P<0.05）. ConclusionMuscone and dehydroepiandrosterone can be used for the differentiation of Xihuangwan samples containing natural musk from those containing artificial musk. This study systematically and comprehensively analyzed the differences in the types and contents of major volatile components in Xihuangwan prepared with natural musk and artificial musk， providing a scientific basis for quality evaluation and control of Xihuangwan.

ObjectiveGastrodia elata has evolved ecological types with shortened rhizome internodes and diversified flower and fruit coloration in response to different altitudes. Studying the genetic mechanisms of different ecotype germplasm is significant for guiding variety breeding in different cultivation areas. MethodsThe bHLH gene family was identified based on the whole-genome datasets of G. elata f. elata and G. elata f. glauca. Subsequently， the gene family members were subject to analysis， including gene structure， chromosomal localization， cis-acting elements， gene synteny， and phylogeny. Combined with transcriptome data and quantitative Real-time PCR， the expression patterns of bHLH genes in the stems of the different G. elata ecotype germplasm were analyzed. Finally， correlation analysis was conducted between gene expression patterns and color to obtain the key bHLH genes regulating the color formation of stem. ResultsA total of 63 bHLH genes were identified in both G elata f. elata and G. elata f. glauca， unevenly distributed across 17 chromosomes and clustered into 16 subfamilies， with significant expansion in some family members. Obvious inversions of bHLH genes on the same chromosome and interchromosomal translocations were detected in the two ecotype germplasm. Among these genes， 12 bHLH genes （such as bHLH62-3 and bHLH74） were associated with the bright yellow color of G elata f. elata stem， while 9 bHLH genes （such as PIL13， UNE12， and bHLH130） were correlated with the red color of G. elata f. glauca stem. Compared to G. elata f. glauca， the bHLH48 expression level was significantly higher in flowers and scale leaves of G elata f. elata， and the bHLH62-3 expression level was significantly higher in all organs of G elata f. elata. ConclusionsFunctional pathway divergence of the bHLH family members has occurred across different chromosomes in G elata f. elata and G. elata f. glauca. Through synergism or antagonism with other genes， 21 bHLH genes participate in the coloration metabolic pathway regulation of stems， flowers， and fruits. Specifically， bHLH62-3 is involved in regulating stem color differentiation in the anthocyanin biosynthesis pathway of G. elata， thus relevant to the color formation of stem. Additionally， GebHLH48 positively regulates flowering-related pathways to promote the early-flowering phenotype of G. elata f. elata. These findings have laid the foundation for analyzing the genetic regulatory mechanisms underlying the color formation of the G. elata stem.

The Pharmacovigilance Guidelines for Clinical Application of Traditional Chinese Medicine Injections （hereinafter referred to as the Guidelines） were released by the China Association of Chinese Medicine， with the standard number T/CACM 1563.4—2024. It is the first specialized guideline in China on the approach to pharmacovigilance activities for the clinical application of traditional Chinese medicine injections （TCMIs）. The Guidelines were jointly developed by the Institute of Basic Research in Clinical Medicine， China Academy of Chinese Medical Sciences， along with 30 experts in TCM pharmacovigilance， clinical practice （TCM， as well as integrated traditional Chinese and Western medicine），and evidence-based medicine from across the country. This publication filled the gap in standard documents in this field， both domestically and internationally. The Guidelines were formulated according to GB/T1.1—2020 Directives for standardization—Part 1： Rules for the structure and drafting of standardizing documents， the WHO Handbook for Guideline Development，and other methodological norms. Based on international norms，national laws and regulations，and scientific research results in the field of pharmacovigilance， methods adopted included expert interviews，literature research，nominal group technique， and Delphi method. Then， key points for pharmacovigilance for TCM injections were summarized and clarified in the four critical sections of "monitoring"，"identification"，"assessment"，and "control". The development process of the Guidelines included project initiation， international registration， expert interviews， literature search， and evaluation. Based on the research results of these steps，a draft was formed and revised through multiple rounds of in-group expert discussion and peer evaluations by 56 external experts. After revisions by the working group based on the feedback， the final version was formed. The Guidelines came into effect on January 8，2024，providing suggestions and reference norms for pharmacovigilance in the clinical application of TCMIs. To further promote the application and popularization of the Guidelines and help pharmacovigilance personnel better understand the development process，this study elucidates the background，methodological framework，and key development steps of the Guidelines.

The Pharmacovigilance Guideline for Clinical Application of Chinese Patent Medicine for External Use （T/CACM 1563.5—2024）， the first guideline in China specializing for the clinical safety of Chinese patent medicines for external use， was led by the Institute of Basic Research in Clinical Medicine，China Academy of Chinese Medical Sciences，and jointly developed by more than 30 research institutions of medical sciences across the country. Aiming to standardize the pharmacovigilance activities in the clinical application of Chinese patent medicines for external use，the guideline systematically categorizes potential risks and proposes prevention and control measures that cover 11 core sections of risk monitoring and reporting， signal identification，as well as assessment and control， addressing the gap in domestic and international standardization of this field. The compilation of this guideline strictly adhered to international norms and domestic regulations， involving multiple rounds of expert consultations，hybrid interviews， and evidence integration （covering literature，medical insurance，essential medicine，pharmacopoeia data， and regulatory information）. With the scope of application defined to include medical institutions， pharmaceutical manufacturers and distribution enterprises，as well as regulatory authorities， the guideline focuses on key issues such as inherent medicine risks，quality risks，off-label use，risks of combination therapy，and the safety in special populations. During the compilation，core discrepancies such as the definition of application scope and quality risk control were addressed to ensure alignment with regulations such as the Drug Administration Law of the People's Republic of China and the Good Pharmacovigilance Practice. The guideline is registered internationally （PREPARE—2022CN463）. In the future，the implementation of the guideline will be promoted through hierarchical dissemination，dynamic revision，and post-effectiveness evaluation， contributing to rational clinical use and improved patient safety.

Objective To compare and analyze the changes in the use of lung cancer therapeutic drugs before and after the national initiation of health insurance negotiations, and to study the impact of a series of policies on the use of lung cancer drugs. Methods Descriptive statistical methods were used analyze the basic situation of lung cancer patients and the changes of corresponding therapeutic drugs in Peking University People's Hospital from 2014 to 2020, as well as to the hospital procurement data of lung cancer therapeutic drugs in the database of the Chinese Medicine Economic Information. Results From 2014 to 2020, the total cost per capita of lung cancer patients showed a trend of first increasing and then decreasing, increasing before the national drug negotiation and gradually decreasing after the negotiation. After 2017, the use of small ATC categories such as VEGF/VEGFR inhibitors and EGFR tyrosine kinase inhibitors increased significantly, along with a rise in the number of monoclonal antibody varieties. The DDDs of osimertinib, anlotinib, alectinib, crizotinib and other drugs in the medical insurance list increased significantly, and the average daily cost decreased significantly. Conclusion The number of hospitalization days for lung cancer patients had continued to shorten in recent years, and the structure of drug use had changed significantly. The adjustment of the medical insurance catalog had led to more innovative lung cancer drugs showing the trend of volume up and price down.

ObjectiveTo express and purify the endolysin PlyL from the Bacillus anthracis prophage LambdaBa02 in prokaryotic cells, and to explore its role in the detection of Bacillus anthracis, so as to provide a novel strategy for the specific and rapid detection of Bacillus anthracis.MethodsAccording to the sequence of Bacillus anthracis vaccine strain CVCC40205 registered in GenBank, the plyL gene was amplified by PCR with plyL gene-specific primers and inserted into the prokaryotic expression vector pET28a(+) to construct the recombinant expression plasmid pET28a(+)-His-plyL, which was then transformed into E.coli BL21(DE3) and induced by IPTG. The induced expression conditions were optimized to enhance soluble expression, and the recombinant PlyL protein was purified via nickel-affinity chromatography. The lytic activity of recombinant PlyL protein was assessed by measuring absorbance values, and an ELISA method was established to evaluate the sensitivity and specificity of Bacillus anthracis detection.ResultsThe recombinant expression plasmid pET28a(+)-His-plyL was confirmed to be correctly constructed by NdeⅠ and XhoⅠ double digestion and sequencing. The optimal induction conditions were 0. 5 mmol/L IPTG at 16 ℃ for 16 h. The relative molecular mass of the expressed recombinant PlyL protein was about 28 600. After purification and concentration, the final concentration of the protein was2. 55 mg/mL, and the purity reached 80. 6%. The purified recombinant PlyL protein could reduce the A_(600)value of Bacillus anthracis culture solution. The sensitivity of the preliminarily established ELISA method for detecting Bacillus anthracis was1 × 10~3 CFU/mL, and there was no cross-reactivity against closely related strains such as Bacillus cereus and Bacillus thuringiensis(P < 0. 000 1).ConclusionThe recombinant PlyL protein was successfully expressed and purified in prokaryotic cells, which exhibits both efficient lytic activity and species specificity, making it a promising novel tool for the rapid detection of Bacillus anthracis.