Progress in diagnosis and treatment of gangrenous cholecystitis / 中华外科杂志

Gangrenous cholecystitis is a kind of acute cholecystitis, whose course of disease progresses rapidly, early diagnosis is difficult and mortality is high, and clinicians are prone to misdiagnosis and missed diagnosis in clinical work.However, gangrenous cholecystitis has been ignored in various guidelines.This paper systematically summarized the pathogenesis, pathological manifestations, epidemiology, clinical diagnosis and treatment of gangrenous cholecystitis, hoping to provide a complete and clear diagnosis and treatment process for clinicians.

Two new triterpenes from Maytenus guangxiensis with their antiproliferative activity / 药学学报

Four triterpenoids were isolated and purified from the 95% ethanol extract of Maytenus guangxiensis by silica gel column chromatography, Sephadex LH-20 column chromatography, MCI column chromatography and preparative RP-HPLC. Their structures were determined from their physicochemical properties and spectral data. They were identified as maytguanone A (1), maytguanone B (2), 11α-methoxyurs-12-ene-1β,3β-diol (3), lup-20(29)-ene-3β,11α-diol (4). Compounds 1 and 2 are new triterpenoids, along with compounds 3 and 4 were isolated from M. guangxiensis for the first time. The cytotoxicity of compounds 1, 3 and 4 was evaluated using the MTT procedure with three cancer cell lines. The results show that compound 3 displayed good inhibitory effects against HeLa, with an IC50 of 10.68 μmol·L-1.

Analysis of mortality surveillance of residents in Minhang District of Shanghai from January to April in 2016-2020 / 上海预防医学

Objective:To characterize the mortality rate of residents in Minhang District of Shanghai from January to April in 2016-2020， and to determine the change in the epidemic Coronavirus Disease 2019 （COVID-19） in 2020. Methods:Data of mortality surveillance was collected from the death registry of Shanghai residents. Cause of death was coded and classified per the International Classification of Diseases （ICD-10）. The standardized mortality rate was calculated based on the standard population of China in 1990. The analysis was performed by Excel 2016 and SPSS 20.0. Results:From 2016 to 2020， the average crude mortality rate of residents was 281.75/100 000 from January to April in Minhang District of Shanghai， and the standardized mortality rate was 66.57/100 000. The top five causes of death in the latest five years were cardiovascular diseases， tumor， respiratory diseases， endocrine diseases， and injury and poisoning. The mortality rate was the lowest from January to April in 2020 in the past five years； furthermore， the mortality rate of respiratory system diseases has decreased significantly. Conclusion:Sex， age， place and causes of death in residents are consistent from January to April across years in Minhang District of Shanghai. However， there are minor differences in 2020， which may be attributable to the epidemic of COVID-19.

A new polyacetylene from the stems and leaves of Chrysanthemum morifolium Ramat / 药学学报

Eight polyacetylenes were isolated from the extract of the stems and leaves of Chrysanthemum morifolium by various chromatographic methods. Their structures were determined as 2E,4E,12Z-tetradecatriene-1-pyrrolidine-1-oxo-8,10-diynoic (1), tetradeca-2E,4E,12E-trien-8,10-diynoic acid pyrrolidide (2), tetradeca-2E,4E-dien-8,10-diynoic acid pyrrolidide (3), tetradeca-2E,4E,10Z-trien-8-ynoic acid pyrrolidide (4), 2E,4E,12E-tetradecatriene-8,10-diynoic acid isobutylamide (5), 2E,4E-undecyldiene-8,10-diynoic acid isobutylamide (6), 2E,4E,10E-N-isobutyl-2,4,10-tetradecatrien-8-ynoic acid amide (7), and undeca-2E,4E-diene-8,10-diynoic acid phenylethylamide (8) by spectroscopic methods, including UV, IR, ESI-MS, HR-ESI-MS, 1D and 2D NMR spectra. Among them, compound 1 is a new polyacetylene, and compounds 2-8 were isolated from this plant for the first time. Compounds 5-8 inhibited the proliferation of A549 cell significantly at certain concentration, showing potent antitumor activity.

Differences of Structural Plasticity between Hemispheres during Rehabilitation for Subacute Stroke / 中国康复理论与实践

Objective:To explore the differences in plasticity mechanism of cortical structure between hemispheres during rehabilitation for stroke patients at subacute stage. Methods:From October 20, 2018 to February 1, 2020, 22 patients with first-onset subcortical ischemic stroke completed the assessments of MRI and clinical evaluation at admission, and after one and two months of rehabilitation. Cortical surface area, thickness, and volume were measured to evaluate cortical structure plasticity. Two-way repeated measures analyses of variance were implemented to estimate dynamic cortical morphology changes and differences between hemispheres. Results:A significant time effect occurred between admission and after one month of rehabilitation for both hemispheres. Cortical surface area, thickness and volume for most regions in both hemispheres gradually decreased, while parahippocampal gyrus thickness and volume increased. The surface area and volume of postcentral gyrus was significant between both hemispheres (F > 4.305, P < 0.05), in which ipsilesional hemisphere was lower than contralesional hemisphere. The reduction of the thickness (r = -0.474, P = 0.026) and volume (r = -0.432, P = 0.044) of postcentral gyrus in ipsilesional hemisphere was negatively correlated with the recovery rate of motor function. Conclusion:There are differences in cortical structure plasticity during stroke rehabilitation between hemispheres. Cortical morphology markedly changes in the first two months poststroke. The greater the reduction in thickness and volume of postcentral gyrus in ipsilesional hemisphere is, the worse the recovery of motor function may be.

Effect of Individualized Occupational Therapy on Occupational Performance of Patients with Schizophrenia / 中国康复理论与实践

Objective:To explore the effect of individualized occupational therapy on occupational performance of schizophrenic patients. Methods:From 2016 to 2018, 30 schizophrenic patients hospitalized over one year in Beijing Anding Hospital were randomly divided into control group (n = 15) and experimental group (n = 15). The control group was given routine group work activities, and the experimental group was given individualized occupational therapy, 30 minutes a time, once a day, five days a week for four weeks. The Comprehensive Occupational Therapy Evaluation Scale (COTE) was used to evaluate the occupational performance of schizophrenic patients before and after treatment。 Results:The difference value of COTE score was higher in the experimental group than in the control group (t = 3.842, P < 0.01), especially for interpersonal communication behavior and task behavior (t > 3.106, P < 0.01). Conclusion:Individualized occupational therapy could improve the occupational performance of patients with schizophrenia.

Cloning and analysis of CoDXR gene in Cornus officinalis / 中草药

Objective: To clone the full-length cDNA sequence of CoDXR, a key enzyme gene of Cornus officinalis, and provide a basis for further study of C. officinalis. Methods: In this study, we used the transcript sequence c147202_g1 from the transcriptome data of C. officinalis obtained in our laboratory as template, designed specific primers through Primer Premier 5.0, cloned the full-length cDNA sequence of C. officinalis DXR gene by RT-PCR technology, and the bioinformatics analysis and function prediction were carried out through the relevant bioinformatics software. Results: The results showed that the CoDXR gene was 1 505 bp in length and the ORF was 729 bp in length, encoding 242 amino acids. The results of predictive analysis of CoDXR protein by SignalP4.0Server and HMMTOP showed that the protein was a hydrophobic protein without signal peptide and transmembrane region. Phylogenetic tree analysis showed that the CoDXR protein had the highest similarity to the DXR protein sequence of Camellia sinensis. Conclusion: In this study, the key enzyme gene CoDXR was successfully cloned based on the sequencing of the C. officinalis transcriptome, and related bioinformatics analysis was carried out. The results of this study laid the foundation for further study on the function of CoDXR gene in the terpenoid synthesis pathway of C. officinalis.

Preparation and bioactivity of chitosan oligosaccharide: research advances / 国际药学研究杂志

Chitosan oligosaccharide(COS)is the N-acetyl-D-glucosamine and D-glucosamine oligomer linked to β(1→4)glycoside bond, which is an amino oligosaccharide with positive charge. GOS can be prepared via the deacetylation and hydrolysis of chitin from the exoskeleton of arthropod and insect and the cell wall of fungi. GOS is soluble in water, not cytotoxic, easy to be absorbed through intestinal tract, and mainly excreted from urine. COS and its derivatives have been known to have a variety of biological activities, including the anti-inflammatory, immunomodulatory, neuroprotective and antioxidant activities. This paper reviews the research progress in the preparation method, pharmacokinetics, bioactivity and the safety of GOS in recent years, hoping to provide a reference for related future researches.

Evaluation of 3D Measuring Methods for Body Surface Damage and Scars / 法医学杂志

Objective To assess the accuracy and reliability of the two 3D measuring methods, structured-light scanning and single-camera photogrammetry in forensic body surface damage and scar measurement. Methods The measuring results of 86 injuries by the ruler method, structured-light scanning and single-camera photogrammetry were compared and evaluated. The area measuring results of 13 simulated scars by the structured-light scanning, single-camera photogrammetry, Photoshop lasso pixel method and PDF reading software were compared and evaluated. The time consumed was recorded. The known specification information of the stickers was used as the standard value to compare the measuring accuracy of the ruler method, structural-light scanning and single-camera photogrammetry, and to calculate the root mean square error （RMSE）. The consistency evaluation of intraclass correlation coefficient （ICC） for the repeatability of 3 measuring results obtained by different operators and the same operator. Results The differences in results of the two 3D measuring methods and the ruler method had no statistical significance; the differences between measuring results made by the structured-light scanning, single-camera photogrammetry and PDF reading software and that of the Photoshop lasso pixel method had no statistical significance. The post-processing of the single-camera photogrammetry consumed more time than that of other methods. When the long-distance group （10-40 cm） was measured, the results obtained by the ruler method were shorter than the standard value. The RMSE value results were structured-light scanning < single-camera photogrammetry < ruler method. The ICC value intragroup and intergroup were greater than 0.99. Conclusion Both structured-light scanning and single-camera photogrammetry can be applied in recording and measuring forensic body surface damage. The former has better performance in measurement accuracy and stability, while the latter has better color performance but longer post-processing time.

A new alkaloid from Rehmanniae Radix Preparata / 药学学报

The chemical constituents of Rehmanniae Radix Preparatawere prepared according to the traditional method of "jiu zheng jiu shai" and investigated using multiple chromatographic methods. Six alkaloids were isolated and their structures were elucidated from spectral data and physicochemical properties, as follows: rehmanniae alkaloid A (4-{[(5-O-á-D-galactopyranosyloxy)methyl]-1H-pyrrole-2-carbaldehyde-1-yl}butyric acidmethyl ester) (1), baimantuoluoamide B (2), capparisine C (3), harman-3-carboxylic acid (4), (2S)-1-[2-(furan-2-yl)-2-oxoethyl]-5-oxopyrrolidine-2-carboxylate (5), and 1-[2-(furan-2-yl)-2-oxoethyl]pyrrolidin-2-one (6). Among them, compound 1 is a new alkaloid. Compounds 2-6 were newly isolated from Rehmannia glutinosa Libosch.The effect of compounds 1-6 on NRK-52e cell injury induced by LPS was investigated. The results show that compounds 1-3 exhibit protective effects against LPS-induced damage to NRK-52e cells.

Analysis of Cytogenetic Characteristics and Clinical Prognosis in 236 Patients with Myelodysplastic Syndrome / 中国实验血液学杂志

OBJECTIVE@#To investigate the relationship of cytogenetic features, clinical characteristics and prognosis in patients with myelodysplastic syndrome.@*METHODS@#The clinical characteristics and prognosis of 236 patients with MDS admitted to the Affiliated Hospital of Xuzhou Medical University from January 2013 to September 2017 were analyzed retrospectively, the follow-up observation and correlation analysis were performed.@*RESULTS@#There were 33 cases of refractory cytopenia with unilateral dysplasia (RCUD), 8 cases of refractory anemia with ring-shaped iron granulocytes (RARS), 70 cases of refractory cytopenia with multiple dysplasia (RCMD), 23 cases of refractory anemia (RA), 46 cases of refractory anemia with excessive blasts (RAEB-1), 48 cases of (RAEB-2), MDS-U 2 cases, simple del(5q) 6 cases. The detection analysis showed that the chromosome abnormality rate and complex chromosome abnormality rate in RAEB group (RAEB-1 + RAEB-2) and in non-RAEB group (RARS+RCMD+RCUD+RA) were 48.94% vs 43.94%, and 18.09% vs 12.69%, respectively, which were no statistically different. The grouping according to IPSS-R and IPSS showed that the chromosome abnormality rate gradually increased along with enhancement of risk stratifi-cation (P<0.05). The cytogenetic characteristics analysis showed that a total of 108 cases had chromosomal abnormalities, the detection rate was 45.76%, Out of 108 cases, 36 cases had complicated karyotypes, accounted for 15.25% of all patients. The types of chromosomal abnormalities mainly include numbers, structural abnormalities and mixed abnormalities. The chromosome abnormality with the highest detection rate was +8, accounted for 30.56% (33/100) of patients with chromosome abnormalities; followed by -7/7q-, del(5q), del(20q), etc. -7/7q-chromosome abnormalities accounted for 29.63% of all karyotypic abnormalities (including -7/7q-chromosome abnormalities alone and other chromosome abnormalities). The median age of the patients with MDS was 61 (13-88) years old, and the male-female ratio was 1.36∶1. Analysis of blood cell characteristics showed that the three lines were reduced or increased to varying degrees. The median WBC count was 2.8 (0.3-267.1)×10/L, the median Hb level was 69 (20-156) g/L, and the median Plt count was 55 (2-1733)×10/L. The 1 year OS rate in 32 cases of chromosome 7 abnormality and 128 cases of normal chromosome was 25% and 44.53%, respectively, the difference was statistically significant (χ=4.05, P<0.05) .@*CONCLUSION@#Chromosome karyotype is an independent factor affecting the prognosis of patients with MDS. It is important for the diagnosis, treatment and prognosis evalnation of patients with MDS. The overall prognosis of patients with abnormal chromosome 7 is poor. .

Flavonoids with PTP1B inhibition from Broussonetia papyrifera / 中国中药杂志

Eleven flavonoids were isolated from the twigs of Broussonetia papyrifera by column chromatography over silica gel,ODS,MCI gel,and Sephadex LH-20,as well as RP-HPLC.Their structures were identified by spectroscopic methods including NMR,MS,UV,and IR as broupapyrin A(1),5,7,3',4'-tetrahydroxy-3-methoxy-8-geranylflavone(2),8-prenylquercetin-3-methyl ether(3),broussonol D(4),broussoflavonol B(5),uralenol(6),broussonol E(7),8-(1,1-dimethylallyl)-5'-(3-methylbut-2-enyl)-3',4',5,7-tetrahydroxyflanvonol(8),broussoflavonol E(9),4,2',4'-trihydroxychalcone(10),and butein(11).Compound 1 is a new isoprenylated flavonol.Compounds 3,6,10,and 11 were obtained from the genus Broussonetia for the first time,and 4 and 7 were firstly discovered in B.papyrifera.Compounds 1-5 and 7-9 showed significant inhibitory effects on PTP1 B with IC50 values ranging from(0.83±0.30) to(4.66±0.83) μmol·L-1.

Ideal Cardiovascular Health is Inversely Associated with Subclinical Atherosclerosis: A Prospective Analysis / 生物医学与环境科学（英文）

OBJECTIVE@#Ideal cardiovascular health (CVH) could predict a lower risk of developing cardiovascular diseases. This study was conducted to investigate the association between ideal CVH and subclinical atherosclerosis in a population cohort of Chinese adults aged ⪖ 40 years.@*METHODS@#This study was designed as a cross-sectional analysis of 8,395 participants who had complete data at baseline and a prospective analysis of 4,879 participants who had complete data at 4.3 years of follow-up. Ideal CVH metrics were defined according to the American Heart Association. Subclinical atherosclerosis was evaluated by plaques in carotid arteries, carotid intima-media thickness (CIMT), brachial-ankle pulse wave velocity (baPWV), and urinary albumin-to-creatinine ratio (UACR).@*RESULTS@#Both the prevalence and incidence of atherosclerosis measures were found to be decreased with increasing numbers of ideal CVH metrics at baseline (all P values for trend < 0.01). The levels of CIMT and UACR at follow-up showed an inverse and significant association with the numbers of ideal CVH metrics at baseline (both P values for trend < 0.05) but a borderline significant association with baPWV (P for trend = 0.0505). Taking participants with 0-1 ideal metric as reference, we found that participants with 5-6 ideal metrics had significantly lower risks of developing carotid plaques (odds ratio, OR = 0.46; 95% confidence interval, CI 0.27-0.79), increased CIMT (OR = 0.60; 95% CI 0.42-0.84), and increased baPWV (OR = 0.57; 95% CI 0.34-0.97) after full adjustments. A significant interactive effect of age and CVH was detected on CIMT and baPWV progression (both P values for interaction < 0.05).@*CONCLUSION@#The numbers of ideal CVH metrics showed a significant and inverse association with the risk of developing subclinical atherosclerosis in middle-aged and elderly Chinese adults, whereas its dose-response effect was attenuated in individuals aged ≥ 60 years and partially weakened in male participants.

Finite-element analysis of mandibular first molar with two marginal designs of endocrown for the repair of different defects / 华西口腔医学杂志

OBJECTIVE@#This study aimed to evaluate the stress distribution of the mandibular first molar with different thicknesses and heights of the axial wall restored by the endocrown with two marginal designs and thus provide a theoretical basis for selecting clinical preparation through the finite-element method.@*METHODS@#Two marginal endocrowns of the mandibular first molar with different axial-wall thicknesses (t=1, 2, 3 mm) and heights (h=2, 3, 4 mm) were established. Group A was the butt-joint design, whereas group B was the shoulder-surrounded design. After applying vertical and oblique loads , the size and distribution of the maximum principal stress and equivalent stress of residual tooth tissue were recorded.@*RESULTS@#The maximum principal stress and equivalent stress distribution of residual tooth tissue were similar among different models. Group A showed a lower maximum principal stress and equivalent stress than group B at the same thickness and height under vertical load. Meanwhile, under oblique load, the maximum principal stress values of groups A and B decreased with increased thickness at constant height. Group A showed lower equivalent stress than group B at the same thickness and height of 2 and 
3 mm. However, when the height was 4 mm, the trend was reversed.@*CONCLUSIONS@#In mastication, when bearing the vertical force, the retention of the butt-joint marginal endocrown preferred to the shoulder-surrounded one. Given the higher axial wall of the shoulder-surrounded marginal endocrown, it showed better ability to bear the oblique force than the butt-joint one.

Enantiomeric pairs of meroterpenoids from Rhododendron fastigiatum / 中国天然药物

Five pairs of optically pure meroterpenoid enantiomers (1a/1b-5a/5b) and two known compounds (6 and 7) were isolated from Rhododendron fastigiatum. Compounds 1a/1b-5a/5b were resolved from naturally scalemic mixtures by chiral HPLC. Their structures were elucidated by spectroscopic methods, X-ray crystallographic experiments, and ECD analyses. Compounds 1a/1b, 2a/2b, 3b, 4a/4b, and 5a/5b were new meroterpenoids with different polycyclic systems. Two enantiomeric pairs (2a/2b and 3a/3b), 6, and 7 exhibited inhibitory effects on protein tyrosine phosphatase 1B (PTP1B) in vitro.

Analysis of Metabolic Components of Estrogenic Sites of Cuscuta chinensis in Serum and Feces of Rats / 中国药学杂志

OBJECTIVE: To identify the metabolites of Cuscuta chinensis in the serum and feces of rats with estrogenic estrogen, and to provide the basis for elucidating the pharmacological basis of its efficacy. METHODS: Using the HPLC-ESI-MS/MS technique, the molecular weight and molecular formula of the compounds were preliminarily estimated by the first-order mass spectrometry, and the chemical constituents of serum and feces were characterized by the retention time of the standard, the fragment ion information, the fragmentation law of mass spectrometry and the reference data. RESULTS: Five prototypic components and 4 metabolites were identified in the serum. A total of 11 chemical constituents were identified in the feces after administration, including 5 prototype components and 6 metabolites. CONCLUSION: Through the comparative analysis between serum and feces, the main metabolic pathways of Cuscuta chinensis compound are deduced, which provides reference for the basic research on the estrogenic substance of Cuscuta chinensis.

Qualitative analysis of metabolites of ethanol extract of Cuscuta chinensis by HPLC-Q/TOF MS/MS / 中草药

Objective To qualitatively analyze the chemical constituents in rats after intragastric administration of estrogenically active ethanol extract of Cuscuta chinensis. Methods The high performance liquid chromatography quadrupole time-of-flight mass spectrometry (HPLC-Q/TOF MS/MS) was used to identify the prototypes and metabolites in rat urine. Results Twelve chemical constituents were identified in the drug-containing urine, including six prototypes and six metabolites. The prototypes are kaemoferol-3-β-D-glucuronide, 6-O-(E)-p-coumaroyl-β-D-fructofuranosyl-(2→1)-α-D-glucopyranoside, aempferol-7-rhamnoside, chlorogenic acid, and apigenin. The metabolites are p-hydroxycinnamic acid, p-hydroxyphenylpropionic acid, isorhamnetin, kaempferol-3-O-glucoside, acetyl caffeic acid, and quercetin sulfate. Conclusion The method of HPLC-Q/TOF MS/MS is simple and rapid for the analysis of prototype components and metabolites in rats urine after oral administration of ethanol extract of C. chinensis, providing the basis for further clarification of the estrogen material basis of C. chinensis.

Septation of the Intrapericardial Arterial Trunks in the Early Human Embryonic Heart / 中华医学杂志(英文版)

<p><b>Background</b>Outflow tract (OFT) septation defects are a common cause of congenital heart disease. Numerous studies have focused on the septation mechanism of the OFT, but have reported inconsistent conclusions. This study, therefore, aimed to investigate the septation of the aortic sac and the OFT in the early embryonic human heart.</p><p><b>Methods</b>Serial sections of 27 human embryonic hearts from Carnegie stage (CS) 10 to CS19 were immunohistochemically stained with antibodies against α-smooth muscle actin (α-SMA) and myosin heavy chain.</p><p><b>Results</b>At CS10-CS11, the OFT wall was an exclusively myocardial structure that was continuous with the aortic sac at the margin of the pericardial cavity. From CS13 onward, the OFT was divided into nonmyocardial and myocardial portions. The cushion formed gradually, and its distal border with the OFT myocardium was consistently maintained. The aortic sac between the fourth and sixth aortic arch arteries was degenerated. At CS16, the α-SMA-positive aortopulmonary septum formed and fused with the two OFT cushions, thus septating the nonmyocardial portion of the OFT into two arteries. At this stage, the cushions were not fused. At CS19, the bilateral cushions were fused to septate the myocardial portion of the OFT.</p><p><b>Conclusions</b>Data suggest that the OFT cushion is formed before the aortopulmonary septum is formed. Thus, the OFT cushion is not derived from the aortopulmonary septum. In addition, the nonmyocardial part of the OFT is septated into the aorta and pulmonary trunk by the aortopulmonary septum, while the main part of the cushion fuses and septates the myocardial portion of the OFT.</p>

Clinical Value of Pulmonary Artery Parameters and Pulmonary Valve Annulus Z Scores for Choosing the Type of Operation in Complete Repaire of Pediatric Tetralogy of Fallot / 中国循环杂志

Objective: To investigate the clinical value of transthoracic echocardiography (TTE) measured pulmonary artery parameters and pulmonary valve annulus Z scores for choosing the type of operation in complete repair of pediatric tetralogy of Fallot (TOF) Methods: A total of 143 patients received complete repair of pediatric TOF in our hospital were retrospectively studied. The patient's median age was 8 (1-171) months. Based on the type of operation, patients were divided into 2 groups: Trans-annular patch group, n=100 and Valve sparing repair group, n=43. Conventional TTE parameters, right ventricular outflow parameters and pulmonary valve annulus Z scores were compared between 2 groups; pulmonary valve annulus diameters measured by TTE and surgery were studied by correlation analysis. Results: Compared with Valve sparing repair group, Trans-annular patch group had decreased left ventricular end diastolic diameter (23.14±3.82) mm vs (25.23±4.56) mm, pulmonary valve annulus diameter (8.52±2.18) mm vs (10.01±2.61) mm and main pulmonary artery diameter (67.31 vs 82.91) all P<0.05. With reduced value of pulmonary valve annulus Z scores, the constituent ratio in Trans-annular patch group was gradually increasing and in Valve sparing repair group was gradually decreasing, all P<0.05. Correlation analysis indicated that pulmonary valve diameters measured by TTE and surgery had moderate agreement (r=0.581, P<0.001). Conclusion: TTE measured pulmonary valve annulus diameter, main pulmonary artery diameter and pulmonary valve annulus Z scores were the objective parameters provided to surgeon at pre-operation, which had clear clinical value.

FlaA gene deletion of LM90 SB2 inducing sheep encephalitis and the influence on virulence / 中国人兽共患病学报

The flagellin of Listeria monocytogenes is encoded by flaA gene;there is no detail report about the influence of flaA gene on the virulence of LM90 SB2.FlaA gene-deleted strain was constructed successfully with recombination technology.The influence of FlaA on LM90 SB2 virulence was evaluated by motility,BF formation,LD50,etc.Results showed that the colony morphology did not change,gene-deleted strain still had good genetic stability,but its growth was slow and the motility was decreased in the environment at 25 ℃,the morphological structure of the mutant BF was looser and incomplete,LD50 was increased from 4.27 × 106 cfu to 1.62 × 107 cfu.Results indicated that the flaA gene affected the flagellar formation of LM90 SB2 significantly,the ability of the BF formation and the virulence of the flaA deleted strain were decreased obviously.