1.Characteristics of gut microbiota determine effects of specific probiotics strains in patients with functional constipation.
Haohao ZHANG ; Lijuan SUN ; Zhixin ZHAO ; Yao ZHOU ; Yuyao LIU ; Nannan ZHANG ; Junya YAN ; Shibo WANG ; Renlong LI ; Jing ZHANG ; Xueying WANG ; Wenjiao LI ; Yan PAN ; Meixia WANG ; Bing LUO ; Mengbin LI ; Zhihong SUN ; Yongxiang ZHAO ; Yongzhan NIE
Chinese Medical Journal 2024;137(1):120-122
2.Inhibition of TRAF6 ameliorates myocardial inflammatory injury and cardiac dysfunction via regulating cardiomyocyte inflammation in sepsis mice
Ying ZHOU ; Dajun JIANG ; Yong TIAN ; Yongxiang GU ; Guohui YANG
The Journal of Practical Medicine 2024;40(5):608-614
		                        		
		                        			
		                        			Objective To explore the effects of TRAF6 inhibition on autophagy,myocardial inflammation and cardiac function in septic mice.Methods Twenty-four male Kunming mice were randomly divided into 4 groups:sham,sham + C25-140(sham+C),cecal ligation and puncture(CLP),and cecal ligation and puncture+C25-140(CLP+C)group.Sham+C group and CLP+C group were intraperitoneally injected with C25-140 after operation.LVEF and LVFS were evaluated by ultrasound 24 hours after operation.Serum TNF-α and IL1-β were measured by ELISA.HE staining was used to evaluate myocardial inflammatory response.Autophagosomes and mitochondrial microstructure of cardiomyocytes were observed by transmission electron microscopy.TRAF6 mRNA in myocardial tissue was detected by qPCR.The expression of TRAF6,P62,Beclin-1 and LC3B protein was detected by W-B.The effect of C25-140 on myocardial injury in the septic mice was observed by inhibiting autophagy with 3-MA.Results Compared with the sham group,the levels of TRAF6 mRNA and TRAF6 in the myocardial tissue in the CLP group were significantly increased(P<0.05)and the serum TNF-α and IL1-β concentrations were signifi-cantly increased(P<0.05).Meanwhile,the myocardial tissue HE staining showed inflammatory cell infiltration and the LVEF and LVFS levels were significantly decreased in the CLP group(P<0.05).Compared with CLP group,the CLP+C group showed that the expression of TRAF6 mRNA and TRAF6 protein decreased(P<0.05),serum TNF-α and IL1-β decreased(P<0.05),myocardial histopathological myocardial inflammatory cell infiltration decreased,the LVEF and LVFS levels increased(P<0.05).Electron microscopy showed that the mitochondrial swelling decreased,autophagosomes increased,expression of Beclin-1 and LC3Ⅱ/Ⅰ increased,and P62 expression decreased(P<0.05).As compared with CLP+C group,the CLP+C+3-MA group showed that obvious inflamma-tory cell infiltration in the myocardial pathology and the LVEF and LVFS levels decreased after 3-MA inhibited autophagy(P<0.05).Conclusion Inhibition of TRAF6 can not only ameliorate myocardial inflammatory injury and cardiac dysfunction in septic mice,but promote the involvment of cardiomyocyte autophagy in provention from sepsis-induced myocardial injury.
		                        		
		                        		
		                        		
		                        	
3.Focusing on preoperative evaluation for cataractous eyes after implantable collamer lens
Xiaoying WANG ; Xingtao ZHOU ; Xiangjia ZHU ; Yongxiang JIANG ; Xun CHEN
Chinese Journal of Experimental Ophthalmology 2024;42(3):219-223
		                        		
		                        			
		                        			With increasing age, more and more patients with posterior chamber intraocular lens (ICL) implantation are facing the threat of cataracts to their visual acuity.When examining the eyes of cataract patients after ICL surgery, attention should be paid to whether the density of corneal endothelial cells is greater than 2 000 cells/mm 2, the state of the anterior chamber angle, and whether there are fundus abnormalities such as retinal detachment and choroidal neovascularization.When conducting eye biometry measurement, attention should be paid to the measurement starting and ending lines of anterior chamber depth and lens thickness.If patients undergo ICL combined with corneal refractive surgery, they should be examined with two or more devices to obtain corneal refractive power according to the examination requirements after corneal laser vision correction.When selecting the type of intraocular lens, consideration should be given to the histological characteristics of high myopia.Compared to C- and L- loops, plate-haptic is relatively more stable in patients with high myopia accompanied by large capsules and larger diameters of continuous curvilinear capsulorhexis.Kane, Barrett Universal Ⅱ, Olsen, Hill-RBF formulas for calculating the refractive power of intraocular lenses are more accurate in people with long axial length.It is recommended to perform ICL removal simultaneously with phacoemulsification and intraocular lens implantation, preferably with a surgical incision greater than 2.6 mm.Femtosecond laser assisted cataract extraction surgery, although superior to traditional phacoemulsification in reducing corneal endothelial cell loss, reducing corneal edema, and high-quality capsulorhexis, can cause incomplete capsulorhexis and fragmentation due to the cavitation bubbles, manual adjustment of location, and the impact of lower vault.It is recommended to use it with caution.Ophthalmologists should fully understand and pay attention to the characteristics and difficulties of cataract surgery after ICL surgery, communicate fully with patients, and make personalized surgery to achieve better visual outcomes.
		                        		
		                        		
		                        		
		                        	
4.Metformin pretreatment induces cardiac autophagy to reduce myocardial injury in septic mice
Yong TIAN ; Ying ZHOU ; Yongxiang GU ; Guohui YANG
Chinese Journal of Tissue Engineering Research 2024;28(28):4469-4476
		                        		
		                        			
		                        			BACKGROUND:Sepsis complicated by myocardial injury is characterized by a high mortality.Metformin can prevent sepsis-induced myocardial dysfunction by exerting anti-inflammatory effects,improving oxidative stress,and reducing apoptosis.However,it is unclear whether metformin-induced autophagy plays an important role in the protective effect against sepsis-induced myocardial injury. OBJECTIVE:To explore the effect of metformin pretreatment on myocardial injury in septic mice. METHODS:A total of 40 male Kunming mice were randomly divided into sham operation group,model group,metformin group,and metformin+ 3-methyladenine group,with 10 mice in each group.The latter two groups were intraperitoneally injected with metformin for 14 days at a fixed time every day,and the metformin+3-methyladenine group was intraperitoneally injected with 3-methyladenine 1 hour before modeling.Twenty-four hours after the last injection of metformin,cecal ligation and perforation were used to construct a model of myocardial injury in septic mice.The sham operation group was not ligated and perforated.All mice were sacrificed 24 hours after surgery,and blood and myocardial specimens were collected.The levels of inflammatory factors and myocardial injury markers in serum were detected by ELISA.The mRNA expression of autophagy markers LC3B and p62 in myocardial tissue was detected by RT-qPCR.The protein expression of LC3B,Beclin-1,p62,p-AMPK,and AMPK in myocardial tissue was detected by western blot.The pathological changes in myocardial tissue were detected by hematoxylin-eosin staining. RESULTS AND CONCLUSION:Autophagy was inhibited in septic mice with myocardial injury.Compared with the sham operation group,the levels of serum tumor necrosis factor-α,interleukin-1β,interleukin-6,creatine kinase isoenzyme,and troponin T were increased in the model group(P<0.05),but there was no significant difference in p62,LC3Ⅱ/LC3Ⅰ,and p-AMPK/AMPK between the two groups(P>0.05).Compared with the model group,the levels of tumor necrosis factor-α,interleukin-6,creatine kinase isoenzyme,troponin T,and p62 were decreased in the metformin group(P<0.05),while LC3Ⅱ/LC3Ⅰ,p-AMPK/AMPK and Beclin-1 level were increased(P<0.05).Compared with the metformin group,the levels of tumor necrosis factor-α,interleukin-6,creatine kinase isoenzyme,troponin T,and p62 were increased in the metformin+3-methyladenine group(P<0.05),while LC3Ⅱ/LC3Ⅰ and Beclin-1 level were decreased(P<0.05).Myocardial hematoxylin-eosin staining indicated that myocardial fibers arranged normally in the sham operation group,but disorderedly in the model group,with interstitial edema and a large number of infiltrated inflammatory cells.A small amount of vacuolar changes were observed in the metformin group.The arrangement of myocardial fibers in the metformin+3-methyladenine group was slightly disordered,with more vacuolar changes.To conclude,metformin pretreatment may reduce myocardial injury in septic mice by activating the AMPK signaling pathway and inducing autophagy.
		                        		
		                        		
		                        		
		                        	
5.Protective mechanism of metformin-induced cardiomyocyte autophagy on myocardial injury in septic mice
Yong Tian ; Ying Zhou ; Yongxiang Gu ; Guohui Yang
Acta Universitatis Medicinalis Anhui 2024;59(1):92-98
		                        		
		                        			Objective    :
		                        			To investigate the possible mechanism of metformin  (Met)  -induced  cardiomyocyte autoph- agy in protecting myocardial injury in septic mice.
		                        		
		                        			Methods    :
		                        			 The model of myocardial injury in septic mice was es- tablished by cecal ligation and puncture  ( CLP) .Sixty  Kunming  mice were  randomly divided into sham operation  group  (Sham group) ,model  group   ( CLP  group) ,model  + dimethyl  sulfoxide   ( DMSO)  group  ( CLP  + DMSO  group) ,model + metformin  (Met)  group  (Met  group) ,model + Met + 3-methyladenine  (3-MA)  group  (Met + 3- MA group) ,model + Met + compound C  ( CC) group  (Met + CC  group) ,with 10 mice in each group.The Met, Met + 3-MA and Met + CC groups were intraperitoneally injected with Met  (200 mg / kg) once a day for 2 weeks be- fore modeling.The Met + 3-MA group was intraperitoneally injected with 3-MA  ( 10  mg / kg) 1  h before surgery.   The Met + CC group was intraperitoneally injected with CC  (20  mg / kg) 30 min before surgery.The model was es- tablished 24 h after the last injection of Met.The heart and blood of all mice were collected 24 h after surgery.The  Western blot technique was  employed  to  assess  the  relative  expression  levels  of  microtubule-associated  protein  1  light chain 3  (LC3) isoforms,namely LC3 I and LC3 II,autophagy effector protein 1  (Beclin-1) ,ubiquitin-bind- ing protein 62  (p62) ,B-cell lymphoma / leukemia-2  (Bcl-2) ,Bcl-2-associated X protein (Bax) ,adenosine mono- phosphate  (AMP) kinase  (AMPK) and phosphorylated AMPK (p-AMPK) .Myocardial pathological changes were  observed by hematoxylin-eosin  (HE)  staining.The  changes of myocardial mitochondria and autophagosomes were  observed by electron microscopy.Hematoxylin-eosin  (HE) staining was used to observe the pathological changes of  myocardium. Electron  microscopy  was  used  to  observe the changes of  myocardial mitochondria and autophago- somes. 
		                        		
		                        			Results    :
		                        			   Compared  with  Sham  group,the relative protein expression of Beclin-1,p62,p-AMPK / AMPK  and LC3 II / LC3 I in CLP and CLP + DMSO groups had no statistical significance,but Bax increased and Bcl-2 de- creased in CLP group  (P<0. 01) .Compared with CLP group,the relative expression of Beclin-1 protein and LC3  II / LC3 I in Met group increased and p62 decreased  (P<0. 01) ,Bax decreased and Bcl-2 increased  (P<0. 01) .   Compared with Met group,the relative protein expression of Beclin-1 and LC3 II / LC3 I in Met + 3-MA group de- creased and p62 increased  (P<0. 05) ,Bax increased and Bcl-2 decreased  (P<0. 05) .Besides,the relative pro- tein expression of p-AMPK / AMPK in Met + CC group decreased  (P<0. 05) .HE  staining showed that there was  no disorder in myocardial fibers in Sham group,and a large number of inflammatory cells infiltrated the myocardial  fibers of CLP group in a clear disorder.The Met group showed vacuolar changes in the myocardium,while the Met  + 3-MA group showed disordered arrangement of myocardial fibers and a small amount of inflammatory cell infiltra- tion.Under electron microscopy,the morphology of myocardial mitochondria in the Sham group was normal,while  in the CLP group,the arrangement of mitochondrial cristae was disordered with vacuolar changes,and occasional  autophagosomes were observed.Mitochondria in Met group showed slight swelling and a large number of autophago- somes.The mitochondria in the Met + 3-MA group showed significant swelling with a small amount of autophago- somes.
		                        		
		                        			Conclusion    
		                        			The protective effect of metformin on myocardial injury in septic mice can reduce cardiomyo- cyte apoptosis and improve mitochondrial damage by activating AMPK signaling pathway to induce autophagy.
		                        		
		                        		
		                        		
		                        	
6.Pathophysiological characteristics of mice with diabetes combined with SARS-CoV-2 spike protein infection
Xiaoyue SU ; Jingxuan LI ; Ying LIN ; Yongxiang ZHANG ; Zhiyong XIAO ; Wenxia ZHOU
Chinese Journal of Pharmacology and Toxicology 2024;38(6):410-419
		                        		
		                        			
		                        			OBJECTIVE To establish a mouse model of diabetes mellitus(DM)combined with severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)infection to investigate the important pathophysiological changes in the development of DM combined with SARS-CoV-2 infection.METHODS Wild-type(WT)mice and transgenic mice expressing the human angiotensin-converting enzyme 2 receptor driven by the cytokeratin-18 gene promoter(K18-hACE2)were randomly divided into the control group,DM group,SARS-CoV-2 spike protein(S)infection group and DM combined with S protein infection group,with 10 to 12 mice in each group.All the mice were induced by 10 weeks of high-fat diet combined with 40 mg·kg-1 streptozotocin(STZ)for 3 days by ip,except those in the control group or S protein infection group.The control group was given the same volume of 0.1 mol·L-1 sodium citrate buffer.Mice in the S protein infection group and DM+S protein infection group were additionally given 50 μL mixture of 15 μg SARS-CoV-2 spike protein and 1 g·L-1 polyinosinic-polycytidylic acid(poly[I:C])via intranasal drops,while the control group was given an equal volume of sterile water.The glucose tolerance level and pancreatic islet β cell function of mice were evaluated via oral glucose tolerance test at the 6th week of high-fat feeding and 1 week after the administration of STZ by ip.From the 6th week of high-fat feeding to 2 weeks after the administration of STZ,the random blood glucose and fasting blood glucose of mice were measured by a blood glucose meter.Blood samples were taken from subman-dibular veins of 3 mice in each group at 24,48 and 120 h after S protein infection,and lung tissues were taken after euthanization.The pathological changes of lungs of DM mice before and after S protein infection were observed by HE staining.Except for the DM group,blood samples were collected before S protein infection and at 6,24,48,72 and 120 h after infection.The levels of plasma interleukin 1β(IL-1β),IL-2,IL-6,IL-10,IL-17,interferon gamma-induced protein 10(IP-10),interferon γ(IFN-γ),tumor necrosis factor α(TNF-α),monocyte chemotactic protein-1(MCP-1)and granulocyte-colony stimulating factor(G-CSF)were detected by Luminex.The plasma levels of heparan sulfate(HS)were measured by enzyme-linked immunosorbent assay.The levels of cytokines and HS were correlated with the degree of pathological damage by Spearman correlation analysis.RESULTS STZ and high-fat diet could induce DM-like expression in mice,and the random blood glucose(P<0.01)and fasting blood glucose(P<0.05)after 1 week in the hACE2-DM group were significantly higher than in the WT-DM group,and the degree of islet function damage in hACE2-DM mice was significantly higher than that of WT-DM mice(P<0.05).Compared with the DM group,the DM+S group showed more severe pulmonary pathological changes after S protein infection,accompanied by a large number of inflammatory infiltrations and thickening of lung interstitial.Compared with the control group,the levels of pro-inflammatory cytokines G-CSF,IL-6 and IP-10 in the plasma of the WT-S group were significantly increased at 6 h after S pro-tein infection(P<0.01),and those of pro-inflammatory cytokine IL-17 and anti-inflammatory cytokine IL-10 were significantly increased at 24 h after S protein infection(P<0.05).Compared with the control group,the plasma levels of pro-inflammatory cytokines IL-1β,IL-6,TNF-α,MCP-1,G-CSF and IP-10 in the hACE2-S group were significantly increased at 6 h after S protein infection(P<0.05,P<0.01).IL-17 was significantly increased at 24 h and 6 h after S protein infection in the WT-DM+S group and hACE2-DM+S group,respectively(P<0.01,P<0.05).In the hACE2-DM+S group,IFN-γ and IL-1β were signifi-cantly increased in delay to 48 h(P<0.05,P<0.01),and MCP-1 was significantly increased in delay to 72h(P<0.05).Compared with the control group,the level of HS in the plasma of the WT-S group increased significantly(P<0.05,P<0.01)at 6 h and 24 h after S protein infection,but began to decrease at 48 h.At the same time,compared with the WT-S group,the HS level in the WT-DM+S group was slightly increased at 6 h after infection and decreased at 24 h.Compared with the control group,the HS level in the hACE2-S group was significantly increased at 24 h(P<0.01),as was the case with the WT-S group 24 h,48 h and 120 h after S protein infection.At 6 h,24 h and 48 h after S protein infection,the plasma HS level of the hACE2-DM+S group was significantly increased(P<0.01,P<0.05),and the duration of the increase was longer than in the hACE2-S group.Moreover,the levels of IL-1β,IL-10,MCP-1,IP-10,G-CSF and HS in plasma were positively correlated with the degree of lung dam-age in the DM+S group.CONCLUSION In this study,the mouse model of diabetes combined with SARS-CoV-2 spike protein infection has mimicked part of the pathophysiological features of clinical patients,mainly manifested as blunted immune response and elevated HS levels with longer duration to infection alone.IL-1β,IL-10,MCP-1,IP-10,G-CSF and HS may keep track of the course of disease in patients with diabetes combined with SARS-CoV-2 infection.
		                        		
		                        		
		                        		
		                        	
7.Damage effect and mechanisms of cyclophosphamide to human neuroblastoma SH-SY5Y cells
Jiajia LI ; Jiao WANG ; Wenyi XIAO ; Donghui WEI ; Yongxiang ZHANG ; Ning JIANG ; Wenxia ZHOU
Chinese Journal of Pharmacology and Toxicology 2024;38(8):561-574
		                        		
		                        			
		                        			OBJECTIVE To investigate the damage effect and mechanisms of cyclophosphamide(CTX)and its active metabolite derivative 4-hydroperoxycyclophosphamide(4-HC)to human neuroblas-toma SH-SY5Y cells.METHODS SH-SY5Y cells were treated with CTX[0(cell control),0.01,0.1,1,5,10,20,40 and 80 mmol·L-1]and 4-HC[0(cell control),0.01,0.1,1,5,10,20,40 and 80 μmol·L-1]for 48 h.Cell confluence and morphology were observed by the IncuCyte ZOOM system.Cell viability was assessed by CCK-8 assay.Lactate dehydrogenase(LDH)release was measured by LDH assay kit.SH-SY5Y cells were treated with CTX(0,1,5,10 and 20 mmol·L-1)and 4-HC(0,1,5,10 and 20 μmol·L-1)for 48 h before cell proliferation was analyzed by 5-ethynyl-2′-deoxyuridine(EdU)staining assay.Immunofluorescence was employed to assess the levels of the DNA double-strand break marker γ-H2AX and to evaluate changes in mitochondrial membrane potential.SH-SY5Y cells were treated with CTX(0,1,5 and 10 mmol·L-1)and 4-HC(0,1,5 and 10 μmol·L-1)for 48 h,and the alterations in glycolysis and oxidative phosphorylation levels were analyzed using the Seahorse XFe96 Analyzer.RESULTS Compared with the cell control group,cell confluence and cell viability were significantly reduced in the CTX and 4-HC groups(P<0.01),and the half-maximal inhibitory concentrations(IC50)for CTX and 4-HC were 4.44 mmol·L-1 and 4.78 μmol·L-1,respectively.The release rate of LDH was signif-icantly increased while the percentage of EdU+cells was significantly reduced in the CTX and 4-HC groups(P<0.01).The percentage of γ-H2AX+cells was significantly increased and mitochondrial membrane potential significantly decreased in the CTX and 4-HC group(P<0.05).Treatment with CTX and 4-HC resulted in reduced levels of maximum glycolytic capacity,glycolytic reserve,maximal respi-ration,and ATP production(P<0.05).CONCLUSION CTX and 4-HC exert significant cytotoxic effects on SH-SY5Y cells by disrupting cell membrane structure,impeding cell proliferation,and reducing cell viability.The mechanisms underlying these effects may involve intracellular DNA damage,disturbance of energy metabolism and mitochondrial dysfunction.
		                        		
		                        		
		                        		
		                        	
8.Clinical guidelines for the diagnosis and treatment of osteoporotic thoracolumbar vertebral fracture with kyphotic deformity in the elderly (version 2024)
Jian CHEN ; Qingqing LI ; Jun GU ; Zhiyi HU ; Shujie ZHAO ; Zhenfei HUANG ; Tao JIANG ; Wei ZHOU ; Xiaojian CAO ; Yongxin REN ; Weihua CAI ; Lipeng YU ; Tao SUI ; Qian WANG ; Pengyu TANG ; Mengyuan WU ; Weihu MA ; Xuhua LU ; Hongjian LIU ; Zhongmin ZHANG ; Xiaozhong ZHOU ; Baorong HE ; Kainan LI ; Tengbo YU ; Xiaodong GUO ; Yongxiang WANG ; Yong HAI ; Jiangang SHI ; Baoshan XU ; Weishi LI ; Jinglong YAN ; Guangzhi NING ; Yongfei GUO ; Zhijun QIAO ; Feng ZHANG ; Fubing WANG ; Fuyang CHEN ; Yan JIA ; Xiaohua ZHOU ; Yuhui PENG ; Jin FAN ; Guoyong YIN
Chinese Journal of Trauma 2024;40(11):961-973
		                        		
		                        			
		                        			The incidence of osteoporotic thoracolumbar vertebral fracture (OTLVF) in the elderly is gradually increasing. The kyphotic deformity caused by various factors has become an important characteristic of OTLVF and has received increasing attention. Its clinical manifestations include pain, delayed nerve damage, sagittal imbalance, etc. Currently, the definition and diagnosis of OTLVF with kyphotic deformity in the elderly are still unclear. Although there are many treatment options, they are controversial. Existing guidelines or consensuses pay little attention to this type of fracture with kyphotic deformity. To this end, the Lumbar Education Working Group of the Spine Branch of the Chinese Medicine Education Association and Editorial Committee of Chinese Journal of Trauma organized the experts in the relevant fields to jointly develop Clinical guidelines for the diagnosis and treatment of osteoporotic thoracolumbar vertebral fractures with kyphotic deformity in the elderly ( version 2024), based on evidence-based medical advancements and the principles of scientificity, practicality, and advanced nature, which provided 18 recommendations to standardize the clinical diagnosis and treatment.
		                        		
		                        		
		                        		
		                        	
9.Named Entity Recognition of Traditional Chinese Medicine Ancient Records Based on Multi-feature Fusion
Luyao ZHANG ; Jianhua SHU ; Peng WANG ; Hongxing KAN ; Yongxiang XU ; Jie ZHOU ; Shuxuan TANG
Journal of Medical Informatics 2024;45(11):50-58
		                        		
		                        			
		                        			Purpose/Significance To construct a named entity corpus of traditional Chinese medicine(TCM)ancient records,and to improve the recognition accuracy and applicability of the general domain named entity recognition(NER)model in the field of TCM ancient records.Method/Process Annotation standards for entities in TCM ancient records are formulated,and 2 384 Xin'an medical records are annotated.A RoBERTa-BiLSTM-CRF model is developed,and word vectors with semantic features are generated using the RoBERTa pre-trained language model.The BiLSTM-CRF model is used to learn the global semantic features of sequences and decode and output the optimal label sequence.Dictionary and rule features are incorporated to enhance the model's capability to recognize entity boundaries and categories.Result/Conclusion The model shows a good recognition effect on the named entity corpus of Xin'an medical cases.Integration of domain terminology dictionaries and rule-based features improves the overall Fl score to 72.8%.
		                        		
		                        		
		                        		
		                        	
10.Characterization of the depsidone gene cluster reveals etherification, decarboxylation and multiple halogenations as tailoring steps in depsidone assembly.
Jiafan YANG ; Zhenbin ZHOU ; Yingying CHEN ; Yongxiang SONG ; Jianhua JU
Acta Pharmaceutica Sinica B 2023;13(9):3919-3929
		                        		
		                        			
		                        			Depsides and depsidones have attracted attention for biosynthetic studies due to their broad biological activities and structural diversity. Previous structure‒activity relationships indicated that triple halogenated depsidones display the best anti-pathogenic activity. However, the gene cluster and the tailoring steps responsible for halogenated depsidone nornidulin ( 3) remain enigmatic. In this study, we disclosed the complete biosynthetic pathway of the halogenated depsidone through in vivo gene disruption, heterologous expression and in vitro biochemical experiments. We demonstrated an unusual depside skeleton biosynthesis process mediated by both highly-reducing polyketide synthase and non-reducing polyketide synthase, which is distinct from the common depside skeleton biosynthesis. This skeleton was subsequently modified by two in-cluster enzymes DepG and DepF for the ether bond formation and decarboxylation, respectively. In addition, the decarboxylase DepF exhibited substrate promiscuity for different scaffold substrates. Finally, and interestingly, we discovered a halogenase encoded remotely from the biosynthetic gene cluster, which catalyzes triple-halogenation to produce the active end product nornidulin ( 3). These discoveries provide new insights for further understanding the biosynthesis of depsidones and their derivatives.
		                        		
		                        		
		                        		
		                        	
            

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