1.Mechanism of Rehmannia glutinosa-medicated serum regulating BV2 microglia polarization to interfere with neuroinflammation
Ping TIAN ; Hongzhi AN ; Qian FEI ; Ruifeng LIANG ; Dan YANG ; Xuexia ZHANG ; Wenjing GE ; Yifei LIU ; Hongwei LI ; Deen HAN
China Pharmacy 2026;37(15):1979-1985
OBJECTIVE To study the mechanism of action of Rehmannia glutinosa-medicated serum (RG) in regulating lipopolysaccharide (LPS)-induced polarization of BV2 microglia to interfere with neuroinflammation. METHODS An in vitro neuroinflammation model of BV2 cells induced by LPS was established. Cells were divided into control group, LPS group, 10%RG group, 20%RG group, BAY 11-7082 [nuclear factor kappa B (NF-κB) inhibitor] group, and 20%RG+BAY 11-7082 group. Except for the control group, cells in all other groups were pretreated with corresponding drugs for 12 h and then stimulated with LPS for 24 h. The morphology of cells in each group was observed, and the fluorescence intensity of ionized calcium binding adaptor molecule 1 (Iba-1), inducible nitric oxide synthase (iNOS), CD206, the mRNA expression of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), IL-1β, iNOS, IL-4, IL-10, transforming growth factor-β (TGF-β), arginase-1 (Arg-1), and the Toll-like receptor 4 (TLR4)/NF-κB/NOD-like receptor thermal protein domain associated protein 3 (NLRP3) signaling pathway-related protein expression were detected. RESULTS Compared with the control group, the LPS group showed significant changes in cell morphology, exhibiting a typical M1 activated morphology. The fluorescence intensity of Iba-1 and iNOS, the relative expression levels of TNF-α, IL-6, IL-1β, iNOS mRNA, the relative expression levels of TLR4, NLRP3, caspase-1 p20, IL-1β p17 protein, and the phosphorylation levels of NF-κB p65 and inhibitor of nuclear factor kappa B α were significantly increased (P<0.05). The fluorescence intensity of CD206 and the relative expression levels of IL-4, IL-10, TGF-β, and Arg-1 mRNA were significantly reduced (P<0.05). Compared with the LPS group, the changes in the above indicators in the cells of the 10%RG group, 20%RG group, BAY 11-7082 group, and 20%RG+BAY 11-7082 group were significantly reversed (P<0.05), and there was no statistically significant difference in the comparison of the last three groups (P>0.05). CONCLUSIONS RG can effectively inhibit the overall activation of microglia and correct their M1/M2 polarization imbalance, and its mechanism may be closely related to the inhibition of excessive activation of the TLR4/NF-κB/NLRP3 signaling pathway.
2.A novel perioperative comprehensive care model for elderly patients with lung cancer
Daiping LI ; Rui LIANG ; Nan CHEN ; Peng JIAO ; Wenxin TIAN ; Yixiao CHEN ; Jirong YUE ; Birong DONG ; Lunxu LIU ; Ning GE
Chinese Journal of Clinical Thoracic and Cardiovascular Surgery 2026;33(09):1375-1387
With the accelerating aging of the population, the proportion of elderly patients with lung cancer continues to rise, presenting multiple challenges to perioperative management. This paper systematically reviews the clinical characteristics of elderly lung cancer patients. Based on the comprehensive geriatric assessment, it proposes incorporating seven major geriatric syndromes—frailty, delirium, sarcopenia, cognitive impairment, malnutrition, dysphagia, and mood disorders—into the core evaluation system. By integrating multimorbidity management with complication prevention and control, an integrated "geriatric syndrome-multimorbidity-complication" perioperative management model is constructed. Furthermore, this paper outlines stratified intervention strategies for geriatric syndromes, a "five-step" workflow for comorbidity management, and a comprehensive intervention pathway for complications across the preoperative, intraoperative, and postoperative phases. Multidisciplinary team (MDT) collaboration serves as the core mechanism to achieve individualized comprehensive treatment. This paper aims to provide a novel perioperative comprehensive treatment model for elderly lung cancer patients, which is centered on geriatrics, supported by multidisciplinary collaboration, and guided by precision medicine.
3.Development of the "Clinical Ethics" Course for the Eight-Year Clinical Medicine Program: Explorations and Practices by an Interdisciplinary Teaching Team
Jiangli HAN ; Yali CONG ; Qiong BAI ; Shu LI ; Guangkuan XIE ; Tongyan HAN ; Chuan MA ; Ying YAO ; Fei DONG ; Huilin LIU ; Rui WU ; Qinggang GE ; Liang WANG ; Yuxi XIA ; Shixian GU ; Xuan HE ; Ning SHEN
Medical Journal of Peking Union Medical College Hospital 2026;17(5):1223-1229
With the rapid advancement of medical technology and the increasing complexity of clinical environments, competence in clinical ethical decision-making has become an indispensable core competency for exemplary physicians. However, traditional medical ethics education has long been confronted with the persistent challenges of theory-practice dissociation and the disconnect between pedagogical settings and clinical realities. Thus, how to construct a "Clinical Ethics" curriculum that aligns with the objectives of training high-caliber medical professionals has emerged as a critical and challenging issue in current medical education reform. To effectively address this challenge, the Office of Education at Peking University Third Hospital, since 2021, has assembled a multidisciplinary "Clinical Ethics" teaching and management team comprising faculty from Peking University School of Humanities and key clinical specialists from the hospital. In 2022, the "Clinical Ethics" elective course was formally launched for fourth-year students in the eight-year MD program who had completed coursework in "Medical Ethics" and organ-system-based curricula, with the aim of exploring and operationalizing a pre-clinical ethics education model tailored for senior medical students. The course employs a modular instructional design encompassing "theoretical review-case-based deliberation-clinical workshop", which effectively facilitates the deep integration of medical humanities with clinical practice.Following four years of iterative refinement through the "plan-act-observe-reflect" cycle, the course has demonstrated positive outcomes in enhancing students' ethical awareness and decision-making capabilities, and has preliminarily established a sustainable collaborative mechanism among the multidisciplinary faculty team. This article systematically delineates the course development background, pedagogical model and methodological innovations, and the multidisciplinary collaborative framework, alongside reflections and summaries based on implementation outcomes, with the intent of providing references for the future development of "Clinical Ethics" curricula.
4.Expert consensus on infection prevention and control of Creutzfeldt-Jakob disease in medical institutions
Tianxiang GE ; Yangyang JIA ; Chunhui LI ; Jianrong HUANG ; Xiujuan MENG ; Xiaodong GAO ; Jingping ZHANG ; Fu QIAO ; Lijuan XIONG ; Hui LIANG ; Wei LI ; Haiyan LOU ; Wenjuan WU ; Tianxin XIANG ; Jiansen CHEN ; Biao ZHU ; Kaijin XU ; Zhihui ZHOU ; Hongliu CAI ; Meihong YU ; Yan ZHANG ; Yanwan SHANGGUAN ; Haiting FENG ; Hangping YAO ; Lei GUO ; Tieer GAN ; Weihong ZHANG ; Jimin SUN ; Ye LU ; Qun LU ; Meng CAI ; Jin SHEN ; Yunsong YU ; Anhua WU ; Liu-yi LI ; Tingting QU
Chinese Journal of Infection Control 2025;24(4):437-450
Creutzfeldt-Jakob disease(CJD)is a rapidly progressive and fatal neurodegenerative disorder caused by prions,with certain infectivity and iatrogenic transmission risks.With the rapid progress and application of new dia-gnostic biomarkers and detection methods,as well as the construction and improvement of surveillance and reporting systems,the detection of CJD in patients domestically and internationally has shown an increasing trend year by year.Due to its long incubation period and heterogeneity of early symptoms,early identification and diagnosis of the disease is difficult,increasing the risk of transmission within medical institutions.Currently,there is a lack of con-sensus on the infection prevention and control of CJD.In order to timely identify and diagnose CJD as well as effec-tively block its transmission in medical institutions,this consensus summarizes 15 clinical concerns and formulates 24 specific recommendations based on the latest domestic and international research findings and clinical evidence,as well as combines with clinical practice,aiming to standardize healthcare-associated infection prevention and control measures for CJD and reduce its transmission risk in medical institutions.
5.Incidence and Mortality of Liver Cancer in Fusui County of Guangxi Zhuang Autonomous Region in 2019 and Trend from 2011 to 2019
Yuman FAN ; Yunxi LI ; Jiangshi ZHAO ; Ji CAO ; Zihan ZHOU ; Qiulin LI ; Minhua RONG ; Lianying GE ; Chenglei YANG ; Xiumei LIANG ; Yingchun LIU ; Hongping YU
China Cancer 2025;34(3):195-202
[Purpose]To analyze the incidence and mortality of liver cancer in Fusui County of Guangxi Zhuang Autonomous Region in 2019 and the trend of change from 201 1 to 2019.[Meth-ods]Based on the incidence and mortality data of liver cancer in Fusui County from 2011 to 2019,the crude incidence rate,crude mortality rate,age-standardized rate by Chinese standard population(ASIRC/ASMRC),age-standardized rate by world standard population(ASMRW/ASM-RW),disability-adjusted life years(DALY),years of life lost(YLL),years of lived with disability(YLD)were calculated.The Joinpoint linear regression model was used to calculate the average annual percentage change(AAPC)of the ASIRC/ASMRC and DALY rate of liver cancer in Fusui County from 2011 to 2019.[Results]In 2019,there were 345 new cases and 298 deaths of liver cancer in Fusui County,accounting for 28.49%and 35.86%of all new cases and death cases of malignant tumors in Fusui County,respectively.The crude incidence rate,ASIRC and ASIRW were 74.71/105,67.55/105 and 65.63/105,respectively;the crude mortality rate,ASMRC and ASMRW were 64.53/105,58.78/105 and 56.88/105,respectively.In 2019,ASIRC/ASMRC of men were higher than those of women(105.32/105 and 95.67/105 for men;27.26/105 and 19.11/105 for women).The peak incidence and mortality rates were in the 65~69 and 80~84 age groups,re-spectively.The incidence rate of liver cancer in Fusui County declined from 82.50/105 in 2011 to 67.55/105 in 2019,with an AAPC of-3.01%(P=0.024),but the mortality rate did not have sig-nificant changes(AAPC=-1.44%,P=0.224).The rate of DALY decreased from 14.51/105 to 10.36/105,with an AAPC of-2.82%(P=0.050).[Conclusion]The incidence rate and DALY rate of liv-er cancer in Fusui County showed an overall decreasing trend from 2011 to 2019,but still re-mained at a high level.It is necessary to further strengthen the prevention,screening and early treatment of liver cancer in this region,especially for men and the elderly.
6.Clinical practice of minimally invasive daytime hepatectomy based on enhanced recovery after surgery whole-process management scheme
Jinghao LIN ; Yewei ZHANG ; Qijiang MAO ; Qifang LIU ; Zhaoyang GE ; Hongxia XU ; Renan JIN ; Xiao LIANG
Chinese Journal of Surgery 2025;63(4):331-337
Objective:To explore the clinical effect of the whole-process management scheme of daytime minimally invasive liver resection surgery based on the enhanced recovery after surgery (ERAS) concept.Methods:This is a retrospective case series study. The data of 55 patients who underwent minimally invasive daytime liver resection surgery under the ERAS concept at the Department of General Surgery,Sir Run Run Shaw Hospital, Zhejiang University School of Medicine from January 2023 to August 2024. There were 22 males and 33 females;aged (48.2±15.1) years (range: 16 to 77 years). All patients were classified as Grade 2 according to the American Society of Anesthesiologists physical status classification. Among them, 7 cases were complicated with liver cirrhosis and 10 cases had fatty liver. A multidisciplinary team was formed, consisting of surgeons, anesthesiologists, rehabilitation physicians, psychologists, pharmacists, acute pain management team, operating room nurses, day surgery ward nurses, and ERAS specialized nurses. After strict evaluation by surgeons and anesthesiologists, patients suitable for daytime liver resection surgery were implemented with the ERAS whole-process management plan for liver resection on the basis of routine nursing care.Results:Among the 55 patients, 50 were discharged smoothly within 48 hours, while 5 were transferred to specialized departments for further treatment due to not meeting the discharge criteria, with a smooth daytime discharge rate of 90.9%. Among the 50 patients, 30 underwent laparoscopic surgery and 20 underwent robotic-assisted surgery. The surgery time was (91.6±28.2)minutes(range:45 to 165 minutes), with the intraoperative blood loss of only (30.5±25.5)ml(range:5 to 100 ml). Pathological examination results showed that among the 50 patients, 13 cases had hepatocellular carcinoma, 21 cases had hepatic hemangioma, 4 cases had hepatic cyst, 8 cases had focal nodular hyperplasia, 1 case had low-grade dysplastic nodule, 1 case had hepatolithiasis, 1 case had lymphoma, and 1 case had vascular, fibrous and lymphoid tissue proliferation. There were 44.0% patients who were able to get out of bed on the day of surgery. The hospital stay was (1.8±0.4)days(range:1 to 2 days), and the hospitalization cost was (34 499±20 330)yuan(range:11 724 to 73 488 yuan). No complications requiring special treatment outside the conventional pathway were observed during the hospital stay and follow-up period. At the 2-week outpatient follow-up, no significant abnormalities were found in all patients, and the wound healing was good.Conclusions:The daytime liver resection surgery based on the ERAS whole-process management plan has shown good feasibility in clinical practice. It helps to simplify medical process, shorten hospital stay, and reduce medical costs.
7.Reconstruction of Gustilo ⅢC foot and ankle injury in emergency surgery with Flow-through anterolateral thigh myocutaneous flap combined with grafting of contralateral great saphenous vein
Liang YANG ; Rong ZHOU ; Jihui JU ; Zefeng NIU ; Zhongzheng LIU ; Liping GUO ; Zhijing LIU ; Qianheng JIN ; Chengwei GE
Chinese Journal of Microsurgery 2025;48(2):149-155
Objective:To investigate the clinical efficacy of combination of a Flow-through anterolateral thigh myocutaneous flap with a contralateral great saphenous vein grafting in reconstruction of Gustilo ⅢC foot and ankle injury in emergency surgery.Methods:This retrospective study analysed the clinical data of 9 patients who were admitted in the Department of Wound Repair Surgery, Suzhou Ruihua Orthopaedic Hospital between September 2021 and October 2023. All patients were diagnosed with Gustilo ⅢC foot and ankle injury and met the predefined inclusion criteria. The average age of the patients was 45 (26-64) years. The mean of Mangled Extremity Severity Score (MESS) was 8.2 points, with a range from 5 to 10 points. The wound area after debridement ranged from 15.5 cm×6.0 cm to 24.5 cm×12.5 cm, with the vascular occlusion or defect at 4.0-20.0 (mean, 6.3) cm in length. The size of the flap was 16.5 cm×7.0 cm-25.5 cm×13.5 cm. During surgery, segments of the great saphenous vein were excised in the length of 5.0-21.0 cm, at an approximately 6.5 cm in length. The Flow-through anterolateral thigh myocutaneous flap was employed to reconstruct the soft tissue defect and to establish vascular connections between the anterior or posterior tibial arteries and veins, with the vessels carried by the flap. Additionally, the contralateral great saphenous vein was taken to bridge the posterior or anterior tibial arteries and veins. Follow-ups were carried out by outpatient visits, telephone calls and WeChat interviews. The flap viability, limb blood circulation, wound healing at both donor and recipient sites, as well as functional recovery of the affected limbs was observed. Sensation recovery of the flap was assessed according to the rating standard established by the British Medical Research Council (BMRC) , while the function recovery of foot and ankle was evaluated using the American Orthopaedic Foot and Ankle Society (AOFAS) scale.Results:All flaps successfully survived without vascular complication. Eight affected limbs were effectively cured, while a calf that had an infection and necrosis of a long segment of tibia and fibula was amputated below-the-knee in the stage-II surgery. One of the donor sites of flap was covered with a medium-thickness skin graft from lower abdomen due to the large size of the flap, while the other donor sites were directly sutured and healed at first intention. One patient developed postoperative bone infection, which was successfully treated through re-debridement and antibiotic bone cement filling. Another patient experienced partial necrosis at the distal hallux due to a prolonged limb ischemia, and a stump repair surgery was performed. All patients were entered into the postoperative follow-up for 15.3 (6-24) months. At the final follow-up visit, satisfactory colour and texture were observed on all flaps, although minor oedema was present. Donor sites healed well and the donor limb function was not affected. Sensory evaluation rated S 2 in 5 flaps and S 3 in 3 flaps according to BMRC. Functional assessment of foot and ankle of the affected limb yielded excellent in 2 patients, good in 5 patients and fair in 1 patient according to AOFAS. Conclusion:Flow-through anterolateral thigh myocutaneous flap combined with a contralateral great saphenous vein grafting enables one-stage reconstruction for soft tissue defect and blood circulation of the affected limb. It is a good method in the treatment of Gustilo ⅢC foot and ankle injury in emergency surgery.
8.Clinical effects of free bilateral turbocharged anterolateral thigh flaps in tandem in repairing extensive wounds in the foot and ankle
Liang YANG ; Rong ZHOU ; Jihui JU ; Zefeng NIU ; Zhongzheng LIU ; Liping GUO ; Zhijin LIU ; Qianheng JIN ; Chengwei GE ; Guiyang WANG ; Lin YANG ; Junnan CHENG
Chinese Journal of Burns 2025;41(1):61-69
Objective:To explore the clinical effects of free bilateral turbocharged anterolateral thigh flaps in tandem in repairing extensive wounds in the foot and ankle.Methods:The study was a retrospective observational study. From April 2020 to June 2023, 12 patients with extensive wounds in the foot and ankle who met the inclusion criteria were admitted to the Department of Wound Repair Surgery of Suzhou Ruihua Orthopedic Hospital, including 8 males and 4 females, aged 21 to 65 years. The wound area after debridement ranged from 27 cm×14 cm to 37 cm×20 cm. The bilateral perforator flaps pedicled with either oblique or descending branches of the lateral circumflex femoral artery were designed and harvested based on the size and shape of the wounds. The individual flap incision area ranged from 16 cm×9 cm to 34 cm×12 cm. The non-homologous perforator of the flap on the one side was turbocharged by anastomosing it with the gross muscular branch or main vessel of the oblique or descending branch of the lateral circumflex femoral artery from the flap. Subsequently, the proximal end of the oblique or descending branch of the lateral circumflex femoral artery and its accompanying vein from the flap on the one side were connected end-to-end with either the anterior tibial artery and vein, posterior tibial artery and vein, or dorsal foot artery and vein in the recipient area, the distal end of the oblique or descending branch of the lateral circumflex femoral artery and its accompanying vein from the flap on the one side were anastomosed end-to-end with a source vessel originating from flap on the other side. The wounds in the flap donor areas were sutured directly. The number and source of perforators carried by the flaps and the duration of the flap repair surgery were recorded. The survival of the flap, the occurrence of vascular crisis, and the wound healing at both donor and recipient areas were observed after surgery. The flap condition, appearance and function of the affected limb were observed during follow-up. At the last follow-up, the sensory function of the flap was assessed using the British Medical Research Council's sensory rating standard, the foot and ankle function of the affected limb was evaluated according to the American Orthopedic Foot and Ankle Society scoring standard.Results:A total 24 flaps were successfully harvested, carrying 60 perforators, including 34 perforators from the oblique branch of the lateral circumflex femoral artery, 24 perforators from the descending branch of the lateral circumflex femoral artery, one perforator from the transverse branch of the lateral circumflex femoral artery, and one perforator from the direct branch of the femoral artery. The duration of the flap repair surgery ranged from 4.2 to 9.0 hours. The flaps of 12 patients exhibited complete survival after surgery. A total of two flaps of two patients experienced venous crisis after surgery but survived through emergency exploration. One patient encountered undesirable wound healing at the donor area of flap on the one side after surgery, which healed after dressing change, debridement, and suturing. The remaining patients' donor area wounds healed. Two patients displayed impaired wound healing in the recipient area, which improved after dressing change and resection of residual sequestrum, and the wounds in the recipient area of other patients healed successfully. During the follow-up of 4-26 months, the flaps demonstrated favorable color and texture, slight edematous appearance, and partial sensory recovery, as well as good aesthetic and functional restoration of the affected limbs. At the last follow-up, the sensory function of the flap was assessed as grade S2 in 9 cases and grade S3 in 3 cases; the foot and ankle function of the affected limb was evaluated as excellent in two cases, good in 9 cases, and fair in one case.Conclusions:The bilateral turbocharged anterolateral thigh flaps have numerous sources of perforators. By implementing supercharging of non-homologous perforators within the flap, the vascular supply to the flap is turbocharged, thereby mitigating the risk of extensive flap necrosis. The flap is an effective approach for repairing extensive wounds in the foot and ankle, resulting in improved function of the affected limb after repair.
9.Study of the correlation between bone density and degeneration parameters of small articular process of lumbar vertebra based on QCT
Jingjing LI ; Yutong LI ; Ping LIANG ; Jiaxi LIU ; Wei SUN ; Ge GAO ; Tao WU
China Medical Equipment 2025;22(4):53-57
Objective:To study the correlation between osteoporosis and the joint of small articular process of lumbar vertebra,and the correlation between bone mineral density(BMD)and various parameters of small joint based on quantitative computed tomography(QCT),so as to provide scientific basis for formulating clinically treatment strategies.Methods:This study included 63 patients who admitted to orthopedics of The Second Affiliated Hospital of Liaoning University of Traditional Chinese Medicine from December 2023 to March 2024 due to waist discomfort and lower limb pain.According to BMD standard of CT examination for lumbar vertebra,these patients were divided into normal BMD group(31 cases),osteopenia group(21 cases)and osteoporosis group(11 cases).All patients underwent CT scan on lumbar vertebra.The mode with body membrane were adopted to measure BMD,the area of left and right articular process,CT value,height after the scan was completed.Whether existed osteophytes,endplate inflammation and intervertebral disc herniation in each group were checked.Univariate Analysis of Variance(ANOVA)was employed to assess the differences among different BMD groups in age,gender,area of articular process,CT value and height.The Pathria grading system was adopted to assess the degeneration degree of intervertebral joint,and the Fisher's exact test was used to analyze the differences in degeneration scores of articular process among three groups.At the same time,the pairwise comparison between groups also was conducted.Spearman's rank correlation analysis was conducted to explore the correlation between BMD and the degeneration degree of intervertebral joint.Results:The BMD value of normal BMD group was(165.14±30.11)mg/cm3,and that of osteopenia group was(98.98±10.14)mg/cm3,and that of osteoporosis group was(58.62±18.73)mg/cm3.There was a statistically significant difference in BMD value among three groups(F=103.121,P<0.001),and there was a statistically significant difference in BMD value between normal BMD group and osteopenia group as the result of pairwise comparison between groups(t=10.018,P<0.001).There was statistically significant difference in BMD value between normal BMD group and osteoporosis group(t=12.989,P<0.001),and there was statistically significant difference in BMD value between osteopenia group and osteoporosis group(t=4.641,P<0.001).The areas of left and right upper articular process of normal BMD group were less than that of other two groups,and the differences of CT value and height of left and right upper articular process among three groups were significant(F=27.350,24.458,P<0.05),respectively.The CT value of normal BMD group was higher than that of other two groups,and CT values of right upper articular process of osteopenia group was significantly lower than that of osteoporosis group,and the difference was statistical significance(t=2.191,P<0.05).The heights of left and right upper articular processes of normal BMD group were lower than those of osteoporosis group,and the height of right upper articular process was lower than that of osteopenia group(t=2.331,-2.798,-2.618,P<0.05).There was a negative correlation between osteoporosis degree and the degeneration of articular process joints(r=-0.745,P<0.001).With the decreasing of BMD value,the degeneration of articular process joint gradually aggravated,and the ratios of osteophytes,endplate inflammation and intervertebral discs increased.Conclusion:There is a certain correlation between the osteoporosis and the degeneration of articular process joints of lumbar intervertebral disc.The ratios of osteophytes,endplate inflammation and intervertebral disc herniation increase,and both the area and height of the left and right articular process increase when the reduction of bone mass reaches to a serious degree.
10.Screening and enzyme activity analysis of chitinase-producing strains from tick-de-rived Bacillus
Gejile HU ; Fuli YU ; Jianzhong LIANG ; Yuxin LIU ; Chula KA ; Lageqi YI ; Rigele TE ; Rina SU ; Fang LIU ; Riletu GE
Chinese Journal of Veterinary Science 2025;45(7):1394-1401
The biological activity of chitinase in degrading chitin has garnered extensive attention,particularly for its potential applications in biological control.This study utilized four spore-form-ing Bacillus strains isolated from Dermacentor nuttalli ticks collected in the Hulunbuir region.Traditional bacterial culture methods were employed for isolation and identification,followed by 16S rRNA sequencing and phylogenetic analysis of the purified cultures.chitin-hydrolyzing strains were screened using colloidal chitin plates,and specific chitinase genes were detected via PCR.Fer-mentation was conducted at 37.0 ℃ for 4 d,and the supernatants were subjected to enzyme activity analysis using the DNS method.Four Gram-positive Bacillus strains were successfully isolated from tick tissue samples,they were identified as B.proteolyticus,B.paramycoides,B.thuringien-sis,and B.cereus,and renamed IMH/B-1,IMH/P-1,IMH/T-1,and IMH/C-1,respectively.PCR a-nalysis detected chitinase genes in B.proteolyticus and B.thuringiensis,while B.cereus and B.pa-ramycoides lacked these genes.However,three strains B.proteolyticus,B.thuringiensis,and B.ce-reus demonstrated significant(P<0.01)chitin degradation activity on colloidal chitin.Enzyme ac-tivity assays revealed that chitinase activity ranged from 1.292 to 2.032 U/mL,with B.proteolytic-us exhibiting the highest activity 2.032 U/mL,followed by B.cereus 1.496 U/mL and B.thuring-iensis 1.324 U/mL.This study provides a foundation for further research and application of chiti-nase-producing Bacillus strains.

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