1.Performance evaluation of VA/HA/β-TCP scaffold and its therapeutic effects on infectious bone defects of mice
Ying LIU ; Hua WEN ; Haoyang DING ; Jiliang WANG ; Jun ZHAO
Chongqing Medicine 2025;54(10):2289-2295,2301
Objective To evaluate the drug-loading performance,biocompatibility,bone tissue compati-bility,and therapeutic efficacy of vancomycin(VA)-loaded hydroxyapatite(HA)/β-tricalcium phosphate(β-TCP)scaffolds in treating infectious bone defects in mice.Methods HA/β-TCP scaffolds were fabricated by using 3D printing technology,and VA was loaded onto the scaffolds via freeze-drying to create the composite VA/HA/β-TCP scaffolds.The scaffolds were observed by using scanning electron microscopy(SEM),and their encapsulation efficiency,drug-loading capacity,and release kinetics were assessed.An in vitro co-culture system was established with mouse embryonic osteoblasts(MC3T3-E1)and the scaffolds,The cells were di-vided into the control group(HA/β-TCP scaffolds)and the VA/HA/β-TCP group.Cell viability was assessed by using the methyl thiazolyl tetrazolium(MTT)assay,and osteocalcin(OCN)expression levels were meas-ured by ELISA at 7,12,and 14 days of co-culture.Antibacterial activity was evaluated through adhesion ex-periments.A mouse cranial defect model was constructed and implanted with the scaffolds for 4 weeks.Hema-toxylin and eosin(HE)staining was performed to observe material degradation and bone formation in the sur-rounding tissues.Results The VA/HA/β TCP scaffolds exhibited uniform pore size distribution and excel-lent drug-loading performance,with an encapsulation efficiency of 70.32%and an actual drug-loading rate of 30.53%,effectively loading VA.The scaffolds sustained VA release over 36 hours.Compared to the control group,MC3T3-E1 cell viability on the VA/HA/β-TCP scaffolds was significantly inhibited at 7 and 12 days of co-culture(P<0.01),but no significant difference in proliferation activity was observed between the two groups after 14 days(P>0.05).No significant differences in OCN expression levels were found in MC3T3-E1 cells on the VA/HA/β-TCP scaffolds compared to the control group at any time point(P>0.05).The VA/HA/β-TCP scaffolds demonstrated strong antibacterial properties,with significantly reduced numbers of Escherichia coli in the co-cultured bacterial solution and on the scaffold surface compared to the control group(P<0.001).Compared with the control group,the VA/HA/β-TCP group demonstrated significantly reduced cranial hemorrhage and inflammatory infiltration,alongside a marked increase in new bone tissue.Conclusion The VA/HA/β-TCP scaffolds exhibit excellent drug-loading performance,controlled drug re-lease,biocompatibility,antibacterial activity,and bone tissue compatibility,offering a novel approach for trea-ting bone infections.
2.Research progress in ultraviolet radiation-induced eye damage and therapeutic drugs
Jiliang CHEN ; Minghui CUI ; Yu WU ; Haobing YU ; Xiaoyu LIU ; Bo HU
Military Medical Sciences 2025;49(7):542-547
High intensity ultraviolet radiation exists in special military operation environments such as oceans,plateaus,polar regions and deserts,which is a leading contributor to eye damage and can lead to luminous keratitis,dry eyes,pterygium,cataract and macular degeneration.Ultraviolet radiation can cause acute and chronic injury to eyes by inducing DNA damage,oxidative stress and inflammatory reaction.The commonly used clinical drugs have played a role in relieving symptoms and promoting the repair of ocular tissues,but there are still limitations.The research on targeted therapeutic drugs,proteins and their derived peptides,vitamins and their coenzymes,as well as natural active ingredients of animals and plants has provided new ideas for the development of more effective drugs that can protect eyes from ultraviolet and for medical support to China's army in special environments.Based on the literature currently available,this paper reviews the eye injury caused by ultraviolet radiation and therapeutic drugs in terms of types of eye diseases,injury mechanisms,treatment strategies and drug development.
3.National bloodstream infection bacterial resistance surveillance report (2022) : Gram-negative bacteria
Zhiying LIU ; Yunbo CHEN ; Jinru JI ; Chaoqun YING ; Qing YANG ; Haishen KONG ; Haifeng MAO ; Hui DING ; Pengpeng TIAN ; Jiangqin SONG ; Yongyun LIU ; Jiliang WANG ; Yan JIN ; Yuanyuan DAI ; Yizheng ZHOU ; Yan GENG ; Fenghong CHEN ; Lu WANG ; Yanyan LI ; Dan LIU ; Peng ZHANG ; Junmin CAO ; Xiaoyan LI ; Dijing SONG ; Xinhua QIANG ; Yanhong LI ; Qiuying ZHANG ; Guolin LIAO ; Ying HUANG ; Baohua ZHANG ; Liang GUO ; Aiyun LI ; Haiquan KANG ; Donghong HUANG ; Sijin MAN ; Zhuo LI ; Youdong YIN ; Kunpeng LIANG ; Haixin DONG ; Donghua LIU ; Hongyun XU ; Yinqiao DONG ; Rong XU ; Lin ZHENG ; Shuyan HU ; Jian LI ; Qiang LIU ; Liang LUAN ; Jilu SHEN ; Lixia ZHANG ; Bo QUAN ; Xiaoping YAN ; Xiaoyan QI ; Dengyan QIAO ; Weiping LIU ; Xiusan XIA ; Ling MENG ; Jinhua LIANG ; Ping SHEN ; Yonghong XIAO
Chinese Journal of Clinical Infectious Diseases 2024;17(1):42-57
Objective:To report the results of national surveillance on the distribution and antimicrobial resistance profile of clinical Gram-negative bacteria isolates from bloodstream infections in China in 2022.Methods:The clinical isolates of Gram-negative bacteria from blood cultures in member hospitals of national bloodstream infection Bacterial Resistant Investigation Collaborative System(BRICS)were collected during January 2022 to December 2022. Antibiotic susceptibility tests were conducted by agar dilution or broth dilution methods recommended by Clinical and Laboratory Standards Institute(CLSI). WHONET 5.6 and SPSS 25.0 software were used to analyze the data.Results:During the study period,9 035 strains of Gram-negative bacteria were collected from 51 hospitals,of which 7 895(87.4%)were Enterobacteriaceae and 1 140(12.6%)were non-fermenting bacteria. The top 5 bacterial species were Escherichia coli( n=4 510,49.9%), Klebsiella pneumoniae( n=2 340,25.9%), Pseudomonas aeruginosa( n=534,5.9%), Acinetobacter baumannii complex( n=405,4.5%)and Enterobacter cloacae( n=327,3.6%). The ESBLs-producing rates in Escherichia coli, Klebsiella pneumoniae and Proteus spp. were 47.1%(2 095/4 452),21.0%(427/2 033)and 41.1%(58/141),respectively. The prevalence of carbapenem-resistant Escherichia coli(CREC)and carbapenem-resistant Klebsiella pneumoniae(CRKP)were 1.3%(58/4 510)and 13.1%(307/2 340);62.1%(36/58)and 9.8%(30/307)of CREC and CRKP were resistant to ceftazidime/avibactam combination,respectively. The prevalence of carbapenem-resistant Acinetobacter baumannii(CRAB)complex was 59.5%(241/405),while less than 5% of Acinetobacter baumannii complex was resistant to tigecycline and polymyxin B. The prevalence of carbapenem-resistant Pseudomonas aeruginosa(CRPA)was 18.4%(98/534). There were differences in the composition ratio of Gram-negative bacteria in bloodstream infections and the prevalence of main Gram-negative bacteria resistance among different regions,with statistically significant differences in the prevalence of CRKP and CRPA( χ2=20.489 and 20.252, P<0.001). The prevalence of CREC,CRKP,CRPA,CRAB,ESBLs-producing Escherichia coli and Klebsiella pneumoniae were higher in provinicial hospitals than those in municipal hospitals( χ2=11.953,81.183,10.404,5.915,12.415 and 6.459, P<0.01 or <0.05),while the prevalence of CRPA was higher in economically developed regions(per capita GDP ≥ 92 059 Yuan)than that in economically less-developed regions(per capita GDP <92 059 Yuan)( χ2=6.240, P=0.012). Conclusions:The proportion of Gram-negative bacteria in bloodstream infections shows an increasing trend,and Escherichia coli is ranked in the top,while the trend of CRKP decreases continuously with time. Decreasing trends are noted in ESBLs-producing Escherichia coli and Klebsiella pneumoniae. Low prevalence of carbapenem resistance in Escherichia coli and high prevalence in CRAB complex have been observed. The composition ratio and antibacterial spectrum of bloodstream infections in different regions of China are slightly different,and the proportion of main drug resistant bacteria in provincial hospitals is higher than those in municipal hospitals.
4.Expert consensus on clinical application of 177Lu-prostate specific membrane antigen radio-ligand therapy in prostate cancer
Guobing LIU ; Weihai ZHUO ; Yushen GU ; Zhi YANG ; Yue CHEN ; Wei FAN ; Jianming GUO ; Jian TAN ; Xiaohua ZHU ; Li HUO ; Xiaoli LAN ; Biao LI ; Weibing MIAO ; Shaoli SONG ; Hao XU ; Rong TIAN ; Quanyong LUO ; Feng WANG ; Xuemei WANG ; Aimin YANG ; Dong DAI ; Zhiyong DENG ; Jinhua ZHAO ; Xiaoliang CHEN ; Yan FAN ; Zairong GAO ; Xingmin HAN ; Ningyi JIANG ; Anren KUANG ; Yansong LIN ; Fugeng LIU ; Cen LOU ; Xinhui SU ; Lijun TANG ; Hui WANG ; Xinlu WANG ; Fuzhou YANG ; Hui YANG ; Xinming ZHAO ; Bo YANG ; Xiaodong HUANG ; Jiliang CHEN ; Sijin LI ; Jing WANG ; Yaming LI ; Hongcheng SHI
Chinese Journal of Clinical Medicine 2024;31(5):844-850,封3
177Lu-prostate specific membrane antigen(PSMA)radio-ligand therapy has been approved abroad for advanced prostate cancer and has been in several clinical trials in China.Based on domestic clinical practice and experimental data and referred to international experience and viewpoints,the expert group forms a consensus on the clinical application of 177Lu-PSMA radio-ligand therapy in prostate cancer to guide clinical practice.
5.Analysis of retinal and choroidal blood flow density in the macular areas of both eyes of children with mild monocular myopia
Jiliang NING ; Danxia LIU ; Shaofei XUE ; Xiaoyu LIU ; Jun XU
Journal of China Medical University 2024;53(3):224-229
Objective To assess retinal and choroidal blood flow density in the macular regions of children diagnosed with unilateral low myopia using optical coherence tomography angiography(OCTA).This study aimed to investigate the clinical significance of these mea-surements.Methods A cross-sectional study was conducted on 90 eyes of 45 children with monocular myopia and adolescents aged 8 to 14 years who visited the outpatient department of the Ophthalmology of Dalian Third People's Hospital between June 2022 and February 2023.Optometry was performed after a 1%cyclopentolate cycloplegic muscle paralysis.Eyes with spherical equivalent(SE)-3.00 D to-0.50 D were included in the myopia group,whereas those with SE-0.25 D to<+2.00 D were placed in the non-myopia group.The Master system was used to measure axial length(AL)and corneal curvature radius(CR),and to calculate AL/CR.Heidelberg spectral-domain optical coherence tomography(SD-OCT)was used to perform horizontal linear scanning of the macular area to obtain subfoveal choroidal thickness(SFCT).The OCTA module was used to obtain 3 mm×3 mm choroidal blood flow images,which were imported into ImageJ graphics processing software to obtain the blood flow densities of the superficial choroidal plexus(SCP),deep choroidal plexus(DCP),choroidal capillary(CC),and foveal avascular zone(FAZ).Pearson's correlation was used to examine the correlations between each blood flow parameter and age,AL,CR,AL/CR,and SFCT.Results The SE and SFCT of the myopia group were smaller(P<0.05)than those of the non-myopia group,whereas the AL and AL/CR were significantly larger(P<0.05)than those of the non-myopia group.The DCP blood flow density in the myopia group was significantly lower than that in the non-myopia group(P<0.01).There was no statistically sig-nificant difference between the residual blood flow parameters of the myopia and non-myopia groups(P>0.05).The Pearson's correlation analysis indicated that the SCP and DCP blood flow densities in the myopia group were positively correlated with SE(r= 0.611,0.731,P<0.05),negatively correlated with AL(r=-0.568,-0.712,P<0.05),and negatively correlated with AL/CR(r=-0.557,-0.564,P<0.05).The SCP and DCP blood flow densities were negatively correlated with AL/CR in the non-myopia group(r=-0.615,-0.656,P<0.05).The CC density and FAZ area in the two groups did not correlate with age,SE,AL,CR,AL/CR,or SFCT(P>0.05).Conclusion Com-pared to non-myopic eyes,the eyes of children with mild monocular myopia had lower DCP blood flow density.Moreover,retinal blood flow density in myopic eyes was correlated with SE,AL,and AL/CR,whereas retinal blood flow density in non-myopic eyes was only correlated with AL/CR.
6.National bloodstream infection bacterial resistance surveillance report(2022): Gram-positive bacteria
Chaoqun YING ; Yunbo CHEN ; Jinru JI ; Zhiying LIU ; Qing YANG ; Haishen KONG ; Haifeng MAO ; Hui DING ; Pengpeng TIAN ; Jiangqin SONG ; Yongyun LIU ; Jiliang WANG ; Yan JIN ; Yuanyuan DAI ; Yizheng ZHOU ; Yan GENG ; Fenghong CHEN ; Lu WANG ; Yanyan LI ; Dan LIU ; Peng ZHANG ; Junmin CAO ; Xiaoyan LI ; Dijing SONG ; Xinhua QIANG ; Yanhong LI ; Qiuying ZHANG ; Guolin LIAO ; Ying HUANG ; Baohua ZHANG ; Liang GUO ; Aiyun LI ; Haiquan KANG ; Donghong HUANG ; Sijin MAN ; Zhuo LI ; Youdong YIN ; Kunpeng LIANG ; Haixin DONG ; Donghua LIU ; Hongyun XU ; Yinqiao DONG ; Rong XU ; Lin ZHENG ; Shuyan HU ; Jian LI ; Qiang LIU ; Liang LUAN ; Jilu SHEN ; Lixia ZHANG ; Bo QUAN ; Xiaoping YAN ; Xiaoyan QI ; Dengyan QIAO ; Weiping LIU ; Xiusan XIA ; Ling MENG ; Jinhua LIANG ; Ping SHEN ; Yonghong XIAO
Chinese Journal of Clinical Infectious Diseases 2024;17(2):99-112
Objective:To report the results of national surveillance on the distribution and antimicrobial resistance profile of clinical Gram-positive bacteria isolates from bloodstream infections in China in 2022.Methods:The clinical isolates of Gram-positive bacteria from blood cultures in member hospitals of National Bloodstream Infection Bacterial Resistant Investigation Collaborative System(BRICS)were collected during January 2022 to December 2022. Antibiotic susceptibility tests were conducted by agar dilution or broth dilution methods recommended by Clinical and Laboratory Standards Institute(CLSI). WHONET 5.6 and SPSS 25.0 software were used to analyze the data.Results:A total of 3 163 strains of Gram-positive pathogens were collected from 51 member units,and the top five bacteria were Staphylococcus aureus( n=1 147,36.3%),coagulase-negative Staphylococci( n=928,29.3%), Enterococcus faecalis( n=369,11.7%), Enterococcus faecium( n=296,9.4%)and alpha-hemolyticus Streptococci( n=192,6.1%). The detection rates of methicillin-resistant Staphylococcus aureus(MRSA)and methicillin-resistant coagulase-negative Staphylococci(MRCNS)were 26.4%(303/1 147)and 66.7%(619/928),respectively. No glycopeptide and daptomycin-resistant Staphylococci were detected. The sensitivity rates of Staphylococcus aureus to cefpirome,rifampin,compound sulfamethoxazole,linezolid,minocycline and tigecycline were all >95.0%. Enterococcus faecium was more prevalent than Enterococcus faecalis. The resistance rates of Enterococcus faecium to vancomycin and teicoplanin were both 0.5%(2/369),and no vancomycin-resistant Enterococcus faecium was detected. The detection rate of MRSA in southern China was significantly lower than that in other regions( χ2=14.578, P=0.002),while the detection rate of MRCNS in northern China was significantly higher than that in other regions( χ2=15.195, P=0.002). The detection rates of MRSA and MRCNS in provincial hospitals were higher than those in municipal hospitals( χ2=13.519 and 12.136, P<0.001). The detection rates of MRSA and MRCNS in economically more advanced regions(per capita GDP≥92 059 Yuan in 2022)were higher than those in economically less advanced regions(per capita GDP<92 059 Yuan)( χ2=9.969 and 7.606, P=0.002和0.006). Conclusions:Among the Gram-positive pathogens causing bloodstream infections in China, Staphylococci is the most common while the MRSA incidence decreases continuously with time;the detection rate of Enterococcus faecium exceeds that of Enterococcus faecalis. The overall prevalence of vancomycin-resistant Enterococci is still at a low level. The composition ratio of Gram-positive pathogens and resistant profiles varies slightly across regions of China,with the prevalence of MRSA and MRCNS being more pronounced in provincial hospitals and areas with a per capita GDP≥92 059 yuan.
7.Application of floating acupuncture in the treatment of military training injuries
Weidong HE ; Weichuang CAI ; Liyang LIU ; Yong ZHANG ; Jiliang LIU ; Wuyan LIU ; Danying LIU ; Rong LI ; Shuangshi YANG
Journal of Navy Medicine 2024;45(8):806-809
Objective To explore the clinical effect of floating acupuncture on military training injuries,so as to provide reference for the prevention and treatment of military training injuries.Methods A total of 300 patients with ankle,knee,hip,lower back,neck and shoulder diseases caused by military training were divided into two groups.One group was treated with floating acupuncture,and the other group(control group)was treated with traditional physical therapy,medicine and acupuncture.Visual analogue scale(VAS)and Functional Movement Screening(FMS)were used to assess pain and functional movement before and after treatment,respectively.Results After treatment,VAS scores in the floating acupuncture subgroups were significantly lower than those in the control group,and FMS scores in the floating acupuncture subgroups were significantly higher than those in the control group(all P<0.05).Conclusion Floating acupuncture has significant effect on ankle,knee,hip,lower back,neck and shoulder diseases caused by military training,and it is worthy of popularization.
8.BRICS report of 2021: The distribution and antimicrobial resistance profile of clinical bacterial isolates from blood stream infections in China
Yunbo CHEN ; Jinru JI ; Zhiying LIU ; Chaoqun YING ; Qing YANG ; Haishen KONG ; Jiliang WANG ; Hui DING ; Haifeng MAO ; Yizheng ZHOU ; Yan JIN ; Yongyun LIU ; Yan GENG ; Yuanyuan DAI ; Hong LU ; Peng ZHANG ; Ying HUANG ; Donghong HUANG ; Xinhua QIANG ; Jilu SHEN ; Hongyun XU ; Fenghong CHEN ; Guolin LIAO ; Dan LIU ; Haixin DONG ; Jiangqin SONG ; Lu WANG ; Junmin CAO ; Lixia ZHANG ; Yanhong LI ; Dijing SONG ; Zhuo LI ; Youdong YIN ; Donghua LIU ; Liang GUO ; Qiang LIU ; Baohua ZHANG ; Rong XU ; Yinqiao DONG ; Shuyan HU ; Kunpeng LIANG ; Bo QUAN ; Lin ZHENG ; Ling MENG ; Liang LUAN ; Jinhua LIANG ; Weiping LIU ; Xuefei HU ; Pengpeng TIAN ; Xiaoping YAN ; Aiyun LI ; Jian LI ; Xiusan XIA ; Xiaoyan QI ; Dengyan QIAO ; Yonghong XIAO
Chinese Journal of Clinical Infectious Diseases 2023;16(1):33-47
Objective:To report the results of national surveillance on the distribution and antimicrobial resistance profile of clinical bacterial isolates from bloodstream infections in China in 2021.Methods:The clinical bacterial strains isolated from blood culture from member hospitals of Blood Bacterial Resistant Investigation Collaborative System (BRICS) were collected during January 2021 to December 2021. Antibiotic susceptibility tests were conducted by agar dilution or broth dilution methods recommended by Clinical Laboratory Standards Institute (CLSI). WHONET 5.6 was used to analyze data.Results:During the study period, 11 013 bacterial strains were collected from 51 hospitals, of which 2 782 (25.3%) were Gram-positive bacteria and 8 231 (74.7%) were Gram-negative bacteria. The top 10 bacterial species were Escherichia coli (37.6%), Klebsiella pneumoniae (18.9%), Staphylococcus aureus (9.8%), coagulase-negative Staphylococci (6.3%), Pseudomonas aeruginosa (3.6%), Enterococcus faecium (3.6%), Acinetobacter baumannii (2.8%), Enterococcus faecalis (2.7%), Enterobacter cloacae (2.5%) and Klebsiella spp (2.1%). The prevalence of methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant coagulase-negative Staphylococcus aureus were 25.3% and 76.8%, respectively. No glycopeptide- and daptomycin-resistant Staphylococci was detected; more than 95.0% of Staphylococcus aureus were sensitive to ceftobiprole. No vancomycin-resistant Enterococci strains were detected. The rates of extended spectrum B-lactamase (ESBL)-producing isolated in Escherichia coli, Klebsiella pneumoniae and Proteus mirabilis were 49.6%, 25.5% and 39.0%, respectively. The prevalence rates of carbapenem-resistance in Escherichia coli and Klebsiella pneumoniae were 2.2% and 15.8%, respectively; 7.9% of carbapenem-resistant Klebsiella pneumoniae was resistant to ceftazidime/avibactam combination. Ceftobiprole demonstrated excellent activity against non-ESBL-producing Escherichia coli and Klebsiella pneumoniae. Aztreonam/avibactam was highly active against carbapenem-resistant Escherichia coli and Klebsiella pneumoniae. The prevalence rate of carbapenem-resistance in Acinetobacter baumannii was 60.0%, while polymyxin and tigecycline showed good activity against Acinetobacter baumannii (5.5% and 4.5%). The prevalence of carbapenem-resistance in Pseudomonas aeruginosa was 18.9%. Conclusions:The BRICS surveillance results in 2021 shows that the main pathogens of blood stream infection in China are gram-negative bacteria, in which Escherichia coli is the most common. The MRSA incidence shows a further decreasing trend in China and the overall prevalence of vancomycin-resistant Enterococci is low. The prevalence of Carbapenem-resistant Klebsiella pneumoniae is still on a high level, but the trend is downwards.
9.Study on optimal pulse width of ultra-short pulse Er : YAG laser for improving dentin adhesion
Danjing Zhen ; Rong Xia ; Jiliang Xu ; Zihuan Sun ; Chun Liu ; Jinlan Yu
Acta Universitatis Medicinalis Anhui 2023;58(6):1056-1059,1063
Objective :
To explore the optimal pulse width of ultra-short pulse Er : YAG laser for improving dentin bonding strength.
Methods :
Forty isolated third molars were prepared in the shape of wedge defect in the neck,and the coronal plane was taken.The samples were randomly divided into 5 groups : group G0 was blank group,and groups G1-G4 were treated with 30 MJ,20 Hz Er : YAG laser,and the pulse width was set to 30,40,50 and 60 μs, respectively.The morphology of dentin surface was observed by scanning electron microscopy (SEM) ,and the ratio of calcium to phosphorus was detected by energy dispersive X-ray spectroscopy ( EDX) .The shear bond strength ( SBS) of each group and the fracture form under the type microscope were tested by the universal mechanical tes- ting machine.The effect of different pulse width on improving dentin bonding strength was evaluated.
Results :
SEM observation showed that the stained layer was removed after laser treatment with different pulse widths,and the den- tin tubules were opened to different degrees.The calcium-phosphorus ratio of dentin after laser treatment increased, and the difference of calcium-phosphorus ratio in G2 group was statistically significant (P<0. 05) .The mean value of SBS after the cold and hot cycle experiment was G2 >G3 >G1 >G4 >G0,and the difference between G2 group and G0 group,G1 group,G3 group and G4 group are statistically significant (P <0. 05 ) .The difference between group G0 and groups G1,G2,G3 and G4 was statistically significant (P<0. 05) .The main fracture forms of each group were type 1 and type 3.
Conclusion
The 30 MJ,20 Hz Er : YAG laser pulse width of 40 μs can significantly improve the bond strength of dentin.
10.Screening of marine resistant strain based on PKS and NRPS genes and the activity of its metabolites.
Liying ZHANG ; Junfeng LIU ; Jiliang DONG ; Liming JIN ; Yongbin XU ; Wei ZHENG ; Chunshan QUAN
Chinese Journal of Biotechnology 2022;38(12):4520-4535
Based on polyketide syntheses gene (PKS) and non-ribosomal peptide synthetases gene (NRPS), one strain with high anti-pathogenic activity was screened from 77 strains isolated from Arctic marine sediments and identified. By optimizing the composition of culture medium and fermentation conditions, the production of this strain's active metabolites was improved and the main metabolites were identified by HRMS, 1H NMR and 13C NMR. The antibacterial spectrum of the main metabolites and the effect of the metabolites on cucumber Fusarium wilt were also determined. The results showed that the strain was Bacillus velezensis and it showed growth promoting effect on plants. When the strain was cultured in 5 g/L maltose, 10 g/L tryptone, 10 g/L sodium chloride, at 30 ℃, 150 r/min for 60 h, the diameter of the inhibition zone increased from (16.23±0.42) to (24.42±0.57) mm. The metabolites of this strain mainly contain macrolide compound macrolactin A, which has antagonistic effect on a variety of pathogenic bacteria and fungi. Cucumber seedling experiments showed that the metabolites of this strain had a protective effect on cucumber Fusarium wilt, and showed a good potential for development and application as a biocontrol agent.
Polyketides/pharmacology*
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Fungi
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Bacteria
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Fusarium/genetics*
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Anti-Bacterial Agents/pharmacology*
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Peptide Synthases/genetics*


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